Dissertations / Theses on the topic 'Terrestrial invertebrate'

A bacterial challenge assay was developed utilizing the earthworm, Lumbricus terrestris, in order to assess potential immunotoxic effects from exposure to specific polychlorinated biphenyl congeners. Earthworms were inoculated with Aeromonous hydrophila, establishing a 10-day LD50. In vitro assays for effects of PCBs on phagocytosis agreed with mammalian studies, demonstrating potent suppression of phagocytosis by the non-coplanar PCB congener 138 and no suppression by the coplanar congener 126. However, when the effects of the two PCB congeners were evaluated for suppression of resistance to a whole animal infection challenge assay, coplanar PCB 126 decreased the ability of L. terrestris to withstand infection while non-coplanar PCB 138 did not.

Plans currently exist to extend the range of native woodland within the Scottish Highlands. The effects of such an expansion on birds, mammals and above ground invertebrates have been previously been investigated, but little consideration has been given to soil invertebrates. This research looks at effects of Scots pine (Pinus sylvestris) regeneration on the meso- and macro- soil invertebrate communities. Within the Abernethy Forest Reserve (the largest remaining tract of native Scots pine woodland within the UK) mature woodland (pine-dominated) and moorland (Calluna vulgaris-dominated) sites were chosen on the three soil types present; an iron podzol, humus-iron podzol and peat. Three intermediate regeneration sites, upon two of the soil types, were also selected based on tree density and diameter at breast height (dbh). Together these sites formed two transects representing succession from moorland to mature woodland on the two soil types. At each site soil invertebrates were collected to a depth of 0.1 in and pitfall traps set. Litter bags were placed at the woodland and moorland sites to examine invertebrate succession during Pinus and Calluna litter decomposition. All invertebrates were identified to order and oribatid mites identified further using the morphospecies technique. The influences of soil type, depth, season and tree age on invertebrate communities were analysed using TWINSPAN and CANOCO. Results suggested that differences were present in invertebrate abundance and community structure between the two soil types, with more variation occurring along the peat transect than podzol transect. A number of oribatid morphospecies showed differences in density between transect sites and indicator species were present which separated the younger regenerating sites form older woodland. CANOCO analysis demonstrated that this was primarily due to changes in soil pH and temperature. In litter bags, Calluna showed significantly greater colonisation compared with Pinus at all sites and woodland litter bags supported a greater diversity of invertebrates than comparable moorland bags. Calluna litter is more complex than Pinus and may therefore provide a greater number of niches for invertebrates and shelter from prey. Differences between sites may be due to the presence of species adapted to utilising both litter types at the woodland end of the transect. In general concentrations of N and P significantly influenced the community composition within litter bags (pc0.05), but there were no significant relationships with other macronutrients. This work has shown that there are differences in the invertebrate community composition during the regeneration of Scots pine and decomposition of litter, however it is currently unclear whether these changes are truly successional.

Taking an ecosystem approach to fisheries requires the consideration of relevant ecological processes within research and assessment frameworks. Processes affecting ecosystem productivity can be categorized as biophysical (climate variability, primary production), exploitative (fishing), or trophodynamic (food web interactions). This dissertation incorporates these three governing processes to characterize spatiotemporal diversity and population abundance trends for multiple demersal fish and invertebrate species that inhabit the nearshore zone (15-30 ft. depth) along portions of the U.S. Atlantic east coast. Two large marine ecosystems (LMEs) encompass the U.S. East coast – the Southeast and Northeast U.S. Continental Shelf LMEs. The level of connectivity within and between these two ecosystems is well understood for some individual species, but not generally for the nearshore assemblage. The first research chapter of this dissertation is a spatial diversity analysis of 141 fish and invertebrate species that inhabit nearshore waters from Florida to New York. Latitudinal diversity patterns revealed multiple biotic ecotones, or areas of high species turnover. An ecotone was evident in northern spring near the Cape Hatteras border of the two LMEs, but this barrier dissipated as water temperatures homogenized and assemblage connectivity between ecosystems increased throughout the year. Multiple other biotic ecotones were evident within the Southeast U.S. LME and were explained by seasonality and the proximity and area of adjacent estuarine habitat. The second and third research chapters of this dissertation focus on explaining temporal abundance trends for multiple nearshore fish and invertebrate species within the Southeast U.S. LME. For the second research chapter, abundance trends for 71 species were analyzed during 1990-2013 within a univariate time series modeling framework with the goal of determining the relative importance of climate variability and fishing pressure as governing influences on abundance. A decrease in bycatch mortality explained changes for multiple species, while climate variability governed the dynamics for others. Multivariate ordination revealed similar trends for groups of taxonomically related species, indicating governing processes act on species with similar life histories. An extension of results from the second research chapter, research chapter three explores trophic interactions between the bonnethead shark (Sphyrna tiburo) and five of its prey species within Southeast U.S. LME nearshore waters. Multivariate time series modeling supports a negative effect of bycatch on bonnetheads, and population-level predation effects of larger sharks on multiple prey species. Abundance trends for most prey species were also explained by environmental variability associated with the Pacific Decadal Oscillation, although trophic effects were stronger. This body of work incorporates relevant ecological factors in characterizing diversity and abundance trends for fish and invertebrate species comprising the nearshore demersal assemblage within Southeast and Northeast U.S. LMEs. Results indicate seasonal connectivity between LMEs that require further exploration at multiple spatial scales. Abundance time series modeling for multiple species in the Southeast U.S. LME reveals that fishing and trophodynamics may be relatively more influential drivers than climate variability in this sub-tropical system.

Terrestrial invertebrates were surveyed from south coast heathland environments, Gull Rock and Waychinicup National Park. These study sites chosen from within these two regions consist of both healthy and Phytophthora cinnamomi infected vegetation. Phosphite was being aerially applied to parts of these sites as a preventative treatment for the further spread of Phytophthora dieback disease into healthy areas. The experiment aimed to sample terrestrial invertebrate communities using pitfall traps and a foliage beating technique in Phytophthora dieback affected areas and healthy areas and also before and after phosphite application to assess any potential non-target impacts. Invertebrates were identified and analaysed at ordinal level classification and Coleoptera (beetles) were sorted to morphospecies to assess impacts at a finer taxonomic level. Shannon-Wiener Index of Diversity, Sorenses Index of Similarity, Multi-dimesional Scaling, Multi-variate ANOVA and Univariate ANOV A were all used to decide whether there were any impacts of Phytophthora dieback and Phosphite Application of the invertebrates collected. Analysis revealed strong seasonal effects within data but no trends eluding to impact of Phytophthora dieback or Phosphite application.

According to the exploitation ecosystem hypothesis (EEH), terrestrial ecosystems are characterized by well defined trophic levels and strong trophic interactions with community level tropic cascades. In unproductive terrestrial habitats as tundra heaths, the energy shunt from litter and apparent competition between herbivores and detritivores are expected to be important for the structure and dynamics of the invertebrate community. The aim of this study was to test this hypothesis by investigating if plant litter accumulation was affecting the invertebrate community on a nutrient-poor tundra heath. The study was performed during one summer on the highland part of Joatka research area, in the north of Norway.

The experimental area included 16 plots (100 m² each), of which 12 had been littermanipulated. On four plots the amount of litter was increased by 100 %, on four by 200 % and on four by 400 %. Four plots were untreated and used as control plots. Invertebrates were collected by emergence traps (which cover an area of 1 m²), one trap on each plot and one pitfall trap inside each emergence trap. During the study period, traps were emptied and moved twice, resulting in three sampling periods. The invertebrates collected were counted and their length was measured, than all invertebrates were sorted into taxa and trophic guilds. During the study period, herbivore grazing damage was investigated on all 16 experimental plots, signs of herbivores on leaves of vascular plants in an area covering 3 m2 per plot were noted, for every leaf with signs of herbivory the percentage of leaf area removed was estimated.

Plant biomass and plant species composition were estimated in all experimental plots by harvesting above-ground plant parts. In each plot, two squares were randomly chosen and all biomass in this square was collected. Plant biomass was sorted in to following groups: dwarf birch, billberry, Salix herbacea, Salix spp, graminoids, herbs, lichens, mosses and dwarf shrub. Before weighing the plant material, it was stored in paper bags at room temperature and then dried for 48 h at 40°C. In order to detect fertilisation effects, all bilberry shoots that had been produced during the actual summer were separately weighted when analyzing the plant biomass.

The result showed that the invertebrate community in this area is dominated by carnivores while detritivores, parasitoids and herbivores are quite rare, this was in accordance with previous studies made in the area. Litter manipulation did not create any significant variation in the community structure, but there was a slight tendency that carnivore biomass increased and biomass of herbivores decreased when litter was added to the system. In contrary to this,

gracing activity especially on dwarf willow (Salix herbacea) increased in plots were 100 % and 200 % more litter was added. There is a positive correlation between biomass of herbivores and detritivores but the reason for this seems unclear. No fertilisation effect was detected in litter manipulated plots. The structure and dynamics of the actual community could not be described by the food web theory EEH and energy shunt from litter and apparent competition between herbivores and detritivores. It seems to be several complicating factors to take into consideration when describing this community.

The aim of this work is to analyze if a change in the benthic community can be detected two years after a restoration of a small stream. The samples were taken in a small stream at Tinnerö Eklandskap just south of Linköping. In addition to the restored area, two reference sites upstream and downstream of the restored area were sampled to compare to the restored site. The method used for sampling of benthic fauna in the stream was kick sampling. ASPT, Berger-Parker and Renkonen-indices were used to find out if there was any difference between the reference areas and the restored area. In addition to indices, rank-abundance curves and species lists were made to see if there was any trend difference between the different areas. The only index that showed a difference between the different areas was Berger-Parker diversity index. The reason why there were no greater differences between the areas may be due to the fact that two years is too short to allow time for the benthos to re-colonize the restored area.

The extremely inhospitable Antarctic ecosystems confine plants and invertebrates to sparse and restricted ice-free areas. These species survived for millions of years in isolated refugia where population divergence and differentiation can occur, potentially resulting in speciation. The limited dispersal abilities of invertebrate species combined with their specific habitat requirements and the substantial geographical barriers can drastically reduce the gene flow between different populations, resulting in high genetic differentiation between clusters of individuals. With more than 100 described species, mites are surely the most diverse invertebrate group of Continental Antarctica. Among them, the free-living genus Stereotydeus Berlese, 1901 (Acari: Prostigmata) is represented by 6 Antarctic species of which 5 occur along the coastal zones of Victoria Land and the Transantarctic Mountains. In order to examine the biodiversity and the phylogeographic distribution ranges of Stereotydeus spp. across Victoria Land, I conducted an integrated analysis of the genus through phylogenetic, morphological and population genetics studies on specimens collected from nine localities in Victoria Land. I sequenced the second part of the cytochrome c oxidase subunit I mitochondrial gene (cox1) and a fragment of the 28S ribosomal RNA-encoding gene using mite-specific primers. I morphologically identified and described two novel Stereotydeus species from central and south Victoria Land. While the relationships between the cox1 haplotypes from North Victoria Land are well defined, the distribution of the central-southern species appears more complex. This suggests a possible common evolutionary history in many isolated glacial refugia, with scarce gene flow even within populations probably resulting from inter/intra-specific events influenced by several abiotic/biotic factors. Recent threats to Antarctic biodiversity like accelerated climate change, pollution, biological invasions and the increase of human activities have caused increased calls for adequate conservation measures. Establishing a new distribution map for the Stereotydeus species of Victoria Land may help lay the foundations for future decisions in matters of protection and conservation of the unique terrestrial fauna of Antarctica.

The overall aim of this study was to explore the systematics and biogeographic patterns of the freshwater crayfish genus Engaewa Riek, a strongly burrowing freshwater crayfish restricted to the coastal corner of south-western Australia (SWA). The genus Engaewa is a Gondwanan relict with great potential as a marker of historical processes, due to its high habitat specificity and low dispersal ability. This study comprises an extensive taxonomic and phylogenetic revision of the genus Engaewa (using both molecular and morphological data), a detailed study of its distribution and uses the knowledge gained to explore biogeographic patterns in the biodiversity hotspot of SWA. The molecular analyses undertaken in this project support the monophyly of the genus Engaewa. They also, combined with a re-evaluation of morphological characters, support the recognition of (at least) two new species in addition to the five currently described species. Diagnostic morphological characters for the current species and two additional previously undescribed species, along with an updated taxonomic key, are presented. Engaewa species possess a genetic structure that is highly unusual and is characterised by particularly low intra-population diversity, and very high interpopulation diversity on a scale seemingly not observed in freshwater crayfish before. Based on the updated species designations, the ecology, distribution and conservation status of each species level lineage are also reviewed in this study. A biogeographic interpretation of the phylogenetic trees and population analyses/summary statistics from the genetic data is consistent with a scenario wherein lineages within this genus have undergone cyclical periods of expansion followed by contraction into refugia, in response to repeated changes in both climate and sea-level. This cyclical process concurs with the Taxon Pulse Hypothesis and has driven lineage diversification, via vicariant speciation, causing rapid bursts of speciation within the genus. This study has identified a number of refugia (from periods of inhospitable climate) centered on locations within the Cape-to-Cape region of SWA (i.e. between Cape Naturaliste and Cape Leeuwin) and on the south coast (specifically the region around the town of Walpole), which are supported by information from other taxa likewise adapted to mesic habitat, such as other freshwater crayfish, slaters, frogs, orchids and sedges. Not only does this study recognise biogeographic concordance between these taxa in SWA, it highlights a possible central role for Engaewa in creating habitat for other taxa.

Tetrodotoxin (TTX) is a potent neurotoxin that acts by blocking the pore region of voltage-gated sodium channels in nerve and muscle tissue. This causes paralysis, and often death due to asphyxiation. Interestingly, TTX is found in an array of organisms ranging from bacterial species to vertebrates. Further, TTX is found in both aquatic and terrestrial environments. This range of taxa and environments has led to three common lines of study for ecological research on this toxin: production, predation, and identification of novel TTX bearing taxa. I began my research by also refining a Competitive Inhibition Enzymatic Immunoassay technique for fast, easy, and inexpensive quantification of TTX. I then focused on the three previously mentioned areas of research. Female newts (Taricha granulosa) are known to endow their eggs with TTX in order to protect them from predation. I looked at whether females allocated TTX to their eggs evenly over three years in captivity and compared those levels to TTX levels in eggs directly after capture. I found that eggs had lower levels of TTX following initial capture, but those levels did not change over the next three years. This provides evidence that TTX is endogenously produced in this species. Because of the high levels of TTX in newts, there are few known predators. I observed river otters feeding on newts in a high elevation lake in Oregon. I found that these newts have very low levels of TTX, and that in general high elevation populations in Oregon have low levels of TTX relative to low elevation populations. Finally, I documented TTX in two species of terrestrial flatworm (Bipalium adventitium and Bipalium kewense). Tetrodotoxin has never before been identified in a terrestrial invertebrate species. Further, I found evidence that suggests that TTX is used for both defense and prey capture in these worms. These studies add to our understanding of the evolution of TTX and how it influences interactions between organisms and their biotic and abiotic environments.

Rain forest canopies are renowned for their very high biodiversity and the critical role they play in key ecological processes and their influence on global climate. Despite that New Zealand supports one of the most diverse and extensive epiphyte flora of any temperate forest system, few studies have investigated epiphyte communities and their invertebrate fauna along with factors that influence their distribution and composition. This thesis represents the first comprehensive study of entire epiphyte communities and their resident invertebrate fauna in the canopy of New Zealand’s indigenous forests. The aim of this study was to determine spatial patterns of epiphyte and invertebrate species richness, abundance and community composition in relation to abiotic variables, and in particular, the responses of these communities to elevated temperature and rainfall. This study was carried out in coastal lowland podocarp-broadleaved forests at two sites on the West Coast of the South Island of New Zealand. Samples from 120 mat-forming epiphyte assemblages located on inner canopy branches of 40 northern rata (Metrosideros robusta) trees were studied to characterise the component flora and fauna. Additionally, biomass, branch and tree characteristics and community responses to treatments designed to elevate temperature and rainfall to simulate predicted climate change were measured. This investigation revealed astonishing diversity and functional complexity of epiphyte and invertebrate life in this ecosystem. The 30.6 kg (dry weight) of epiphyte material collected contained a total of 567 species, 170 epiphyte and 397 invertebrate (excluding immature specimens and mites) species, including at least 10 species new to science and many undescribed species Epiphyte communities were found to be dominated by non-vascular plants (80 % of the total species richness), particularly liverworts and invertebrate communities were dominated with respect to abundance (~ 80 % of the total individuals) by Acari, Collembola and Hymenoptera (primarily ants) and functionally by scavengers and ants. Epiphyte and invertebrate communities were highly variable with respect to spatial patterning of species richness, abundance and composition across sites, among trees within sites and among branches within trees. Overall, a highly significant proportion, > 75 %, of the variance could be attributed to differences at the branch level, but these differences could not be explained by the environmental factors measured. There were no consistent relationships between the spatial pattern of epiphytes and invertebrates, or between vascular and non-vascular plants. However, there were significant positive correlations between epiphyte biomass and invertebrate species richness (r = 0.472; p < 0.0001) and abundance (r = -0.395; p < 0.0001), as well as non-living epiphyte biomass and scavenger species richness (r = 0.4; p < 0.0001). Microclimatic measurements taken on epiphyte mats were also highly variable with respect to temperature and relative humidity at similar physical locations within the same tree as well as across trees within sites. There was also considerable variation in the intensity and frequency of climatic extremes, although potentially harmful climatic conditions were experienced by all the epiphyte mats for which weather variables were measured. Negative correlations existed between both epiphyte and invertebrate community composition and increased temperatures expressed as cumulative degree days above 5˚C. However, variability was such that there was no direct evidence that increased temperature and rainfall treatments had an effect on invertebrate species richness, abundance or diversity. Northern rata host trees harbour an astonishingly diverse and complex canopy flora and fauna that is characterised by high spatial variability. Such variability highlights that to determine species distribution and community dynamics in canopy habitats in response to disturbance caused either by climate change or invasive species the structure of entire communities at different taxonomic and spatial scales, along with their responses to microclimatic factors, need to be studied. If such complexities are not taken into account, inappropriate interpretation may result in poor decisions concerning the conservation status, vulnerability and subsequent management of such unique ecosystems.

Terrestrial invertebrates are small poikilothermic ectotherms and are thus susceptible to chronic cold, rapid temperature change and desiccation. In the polar regions, where buffered microhabitat temperatures regularly fall below 0°C and water availability is low, they are particularly vulnerable. However, polar terrestrial invertebrates successfully exist within these climes. Using whole organism experimental techniques, this thesis aims to further understand the capacity of invertebrates to tolerate different stressors, the underpinning physiological adaptations, and the potential impact of continued climate change. For just the second time in a freeze-tolerant polar insect, rapid cold hardening is observed. Acclimation to sub-lethal low temperatures is also demonstrated, through depression of the critical thermal minimum (CTmin) and chill coma temperature. Contrasting strategies of desiccation tolerance vs. resistance are noted, as well as evidence of cross-tolerance to temperature stress. At the opposite extreme, water submergence experiments confirm the first example of an amphibious terrestrial midge. A remarkable capacity to tolerate high temperatures, including those that may occur as a result of climate change, is also observed. This body of work underscores the physiological flexibility of polar invertebrates, which allows them to flourish in environments considered too extreme and inhospitable for most terrestrial species.

Rivers play a vital role in human livelihoods and are likely to undergo substantial alteration due to climate and land use changes from an increasing human population. Mitigating the pressures facing rivers in the world requires scientists and environmental managers to understand the ecological mechanisms, and ultimately the strength, of connections between ecosystems. This understanding of connections between adjacent habitats will enable environmental managers to predict the consequences of perturbing these linkages in the future. In this thesis, aquatic-terrestrial linkages in rivers were investigated using ecologically meaningful variables including abundances, biomasses, stable isotopes and fatty acids. This study is part of a larger project entitled “Connectivity through allochthony: reciprocal links between adjacent aquatic and terrestrial ecosystems in South Africa”, in which a team of researchers assessed a variety of pathways connecting riverine and estuarine systems to land within a catchment in the Eastern Cape, South Africa. I conceptualised the flow of energy within a temperate southern hemisphere river (the Kowie River) within theoretical models of energy flow such as the River Continuum Concept (RCC; presents lotic systems as being longitudinally linked with food webs in shaded headwaters being principally driven by allochthonous energy, with the addition of autochthonous food as a minor carbon source in the lower reaches) and the Riverine Productivity Model (RPM; proposes consumers derive most of their energy from local production of phytoplankton, benthic algae and aquatic plants, as well as directly from riparian zones via terrestrial leaf litter). Using the RCC as a starting point, I collected macroinvertebrates (September 2012 to May 2013) along a longitudinal gradient and grouped them into functional feeding groups (FFGs). The results revealed that gatherers and filterers dominated in the Kowie River, and together represented 50 – 83% of the invertebrate assemblages. There was a general paucity of shredders (relative abundance was ≤ 10% across all sites and seasons). The changes in relative abundances of different FFGs did not follow predictions of the RCC along the longitudinal gradient, as there were no correlations of community structure with some physical attributes (stream width, canopy cover, distance of river) that changed along the river continuum. However, FFG abundances were related to water velocity, total dissolved solids and canopy cover. Broadly, the Kowie River data showed that changes in relative abundances of FFGs along the river continuum could not be explained by changes in physical attributes alone, and may be highly influenced by the availability of food and the chemistry of the stream. Analysis of stable carbon (δ13C) and nitrogen (δ15N) isotopes was used to estimate the contributions of algal and land-based production to consumers over space (six sites) and time (November 2012 to September 2013). Carbon contributions determined by the use of mixing models (Stable Isotope Analysis in R) revealed that consumers in the headwater assimilated mainly terrestrially-derived organic matter, with consumers in the middle and lower reaches assimilating autochthonous basal resources (macrophytes and algae). The findings from this river supported aspects of the RCC (at the headwaters; terrestrial organic matter made up 41% of consumer diets), but overall the data supported the predictions of the RPM (local production made the highest contributions of 50 – 86% to all FFGs across all seasons). The carbon isotopes of consumers and their food sources changed substantially every season, indicating that samples of food sources and consumers should be analysed many times throughout the year to capture that variability and to ensure that ephemeral components of the food web are not missed. To validate the findings from the isotope data, fatty acids were used as complementary tracers to determine the contributions of algal versus terrestrial organic matter to the consumers. Fatty acid tracers for terrestrial (Ʃω3/Ʃω6; 18:2ω6; 18:3ω3) vs aquatic (Ʃω3/Ʃω6; 20:5ω3) sources corroborated the findings from the isotope data set, as the mean ratio of Ʃω3/Ʃω6 in consumers was less than one at the headwaters (indicating allochthony), while middle and lower reaches were associated with Ʃω3/Ʃω6 > 1 (indicating autochthony). In addition to the tracer and FFG analyses for examining trophic connections between land and river, the bidirectional exchange of organisms between the riparian zone and the river was assessed using floating pyramidal traps (to measure emergence) and pan traps (for infalling invertebrates) placed at different sites in the river and the biomass in each trap was determined. The exchanges were variable over space and time, with emergence peaking in summer (169 to 1402 mg m-2 day-1) and declining in winter (3 to 28 mg m-2 day-1). Similarly, infalling invertebrates increased in summer (413 to 679 mg m-2 day-1) and declined in winter (11 to 220 mg m-2 day-1). Biomass measurements are indications of quantity that ignore nutritional quality, so I determined the bidirectional flow of invertebrates using absolute concentrations of physiologically important biochemical compounds (essential and polyunsaturated fatty acids). The fluxes of emergent and infalling arthropods peaked in summer (emergence = 0.3 to 18 mg m-2 day-1 and terrestrial infall = 0.3 to 3 mg m-2 day-1) and declined in winter (emergence = 0.01 to 0.51 mg m-2 day-1 and terrestrial infall = 0.01 to 0.03 mg m-2 day-1). However, during some seasons, no significant differences in polyunsaturated fatty acid flux in either direction were observed; this finding indicated the balance of reciprocal subsidisation via reciprocal flows of animals. Factors such as air temperature and algal productivity affected the reciprocal flows between adjacent habitats, with algal productivity being positively related to emergence while air temperature was positively correlated to infalling terrestrial invertebrates. This research enhances the growing body of literature on the function of riverine systems and offers some invaluable information on the flow of energy and the role played by invertebrates in translocating nutrients from terrestrial systems to aquatic systems and vice versa. This study unifies the concepts of the RCC and RPM and shows that these concepts are not limited only to large rivers, but are applicable to small southern temperate rivers too. However, some tenets of the theoretical models were challenged. For example, it challenges the proposition by the RCC that the fine particulate organic matter leaked from upstream breakdown of coarse particulate organic matter is predominantly allochthonous. Additionally, this study showed that in the headwaters, the RPM underestimated the role of autochthony. Overall, the results showed that the Kowie River and its riparian area are intrinsically connected. Once we understand the mechanisms controlling connections and subsidies across ecotones, we can then start to predict the consequences of disruptions to these connections by climate change and/or land use changes. To make predictions about future perturbations to rivers and riparian zones, studies like this, which considers the form and magnitude of subsidies, are needed to provide baseline information. Algal resources (e.g. epiphyton), macrophytes, riparian plants, terrestrial organisms and aquatic organisms all contributed to aquatic and terrestrial linkages in the Kowie River; therefore, it is important to conserve the different components of these ecosystems.

Little is known about the spatial distribution and abundance of tree holes in New Zealand’s native forests, or the invertebrate communities that they support. I found that tree holes were common on five endemic tree species, belonging to the families Fagaceae and Podocarpaceae in the mixed broadleaf-podocarp rainforest of Orikaka Ecological Area, Buller District, New Zealand. However, tree holes were not uniformly distributed throughout the forest, with more holes found on the three podocarp species, Prumnopitys ferruginea, P. taxifolia and Dacrycarpus dacrydioides, than on Nothofagus fusca or N. menziesii. Nevertheless, Nothofagus fusca had the largest holes of any of the tree species sampled and larger trees generally had larger holes. Large, hole-bearing Nothofagus fusca trees support a specialist hole-dwelling vertebrate fauna in New Zealand and worldwide, tree holes provide habitat for a range of invertebrate species. Using specially-designed emergence traps, I collected invertebrates emerging from naturally-occurring dry tree holes and compared this assemblage with invertebrates inhabiting leaf litter on the forest floor and those dispersing aerially throughout the study area. At the higher taxonomic resolution (i.e., Order or Class), community composition within the tree holes was highly variable, and there was no strong distinction between invertebrates from tree holes, leaf litter or Malaise traps. Moreover, although some beetle species emerging from tree holes were found exclusively in tree holes, most of these were represented by a single individual. Consequently, only minor differences in species composition were detected between beetle assemblages from tree holes, leaf-litter and those aerially dispersing throughout the forest. In contrast, the aquatic invertebrate assemblage within water-filled tree holes was highly distinctive from that in ground-based freshwater ecosystems, with only six aquatic taxa in common between all freshwater habitats. Using experimental water-filled tree-hole microcosms, I found that species richness and community composition within these microcosms were primarily driven by resource concentration, although habitat quality (i.e., water chemistry parameters) was also an important determinant of the identity and composition of colonising species. Overall, my study has shown that tree holes are common in the study area, and are likely to be more abundant in New Zealand’s indigenous forests than previously thought. Moreover, these generally small, discrete forest ecosystems support a diverse array of terrestrial invertebrates as well as a distinctive aquatic invertebrate community that is primarily structured by organic matter resource availability. These findings not only represent an important advance in our knowledge of New Zealand’s freshwater invertebrate biodiversity, but also highlight the need for further investigation into these unique forest canopy habitats which may well be at risk from deforestation and land use change.

Forests surrounding streams affect aquatic communities in numerous ways, contributing to energy fluxes between terrestrial and lotic ecosystems. The five papers in this thesis focus on woody debris, terrestrial invertebrates and light, three factors influenced by riparian zone structure, potentially affecting streams and brown trout (Salmo trutta). The individual strength of these stressors and their interactions with each other are not well studied, and their qualitative effects may differ both spatially and temporally as well as with the size-structure of specific fish populations. Using a combination of laboratory and field experiments, I examined the effects of woody debris, terrestrial invertebrates and light on prey availability and on the growth rates, diets and behavior of different size-classes of trout. My field experiments showed that addition of high densities of large wood affected trout growth in a positive way. This positive effect of large wood on trout growth may be related to prey abundance, as indicated by the high standing crop of aquatic macroinvertebrates on the wood. The positive effects on trout may also be related to decreased energy expenditures in wood habitats, as trout increased the ratio between numbers of prey captured and time spent active and that swimming activity and level of aggression decreased as wood densities were increased in a laboratory experiment. Terrestrial invertebrates are generally assumed to be a high quality prey resource for fish and my field experiments showed that reduction of terrestrial invertebrate inputs had a negative effect on trout growth. The availability of terrestrial prey in the stream was also coupled to trout diet and linked to growth, as fish with high growth rates had high proportions of terrestrial prey in their diets. Light, measured as PAR, did not have an effect on chlorophyll biomass, nor was there an effect on aquatic macroinvertebrates or trout. Hence, even if light levels were sufficient for increased photosynthesis, other factors such as low nutrient content may have limited the effects. Many of my results were dependent on fish-size. I observed, for example, that large trout had higher capture rates on surface-drifting terrestrial prey than small trout when prey densities were intermediate or high, but at low prey densities, the consumption of terrestrial prey by large and small trout were similar. Moreover, although large wood and terrestrial invertebrates affected growth of both small and large trout, the effects were generally more consistent for large trout. Although changes in riparian forests typically induce an array of interacting effects that certainly call for further research, the overall conclusion from this thesis is that many of the factors I have studied have profound effects on stream biota and trout. The positive effects from large wood also propose that adding trees to streams may partly compensate for negative effects associated with riparian deforestation.

The primary objectives of this research were therefore to evaluate polybrominated diphenyl ether (PBDE) bioavailability to ecologically distinct soil invertebrates exposed to Penta-BDE-treated consumer polyurethane foam (PUF) products and biosolid products with incurred PBDEs. In laboratory bioassays, earthworms (Eisenia fetida) bioaccumulated SigmaPBDEs (47+99+100+183) up to 11,000 mug/kg lipid after 28 days from a mixture of artificial soil and anaerobically-digested sludge biosolid (ADB). Earthworms also bioaccumulated SigmaPBDEs (47+99+100+153+154+183) up to 13,500 and 838,000 mug/kg lipid after 28 d from a mixture of artificial soil and composted sludge biosolid (CB) and Penta-BDE-spiked artificial soil (SAS), respectively. No previous lab studies on bioaccumulation of PBDEs from sludge or sludge-amended soils have been published. Two publications, done by the same research group on the same sites in Sweden, do exist documenting incidental levels of PBDEs in worms collected from historically sludge-amended agricultural fields. In the current research, biota-soil accumulation factors (BSAFs) were appreciably higher (dependent upon dose) than those reported in these Swedish field studies. PBDE usage in Sweden has been much less intense than in North America. Increasing BSAFs with decreasing biosolids-amended soil burdens may indicate that PBDE constituents within these biosolid products may impact earthworms at relatively low levels in soil. The potential for a terrestrial arthropod, the house cricket ( Acheta domesticus) to take up PBDEs directly from consumer PUF was also evaluated in a laboratory bioassay. These insects frequent indoor spaces and discarded materials and hence may have increased access (and thus exposure) to PBDE-treated polymers. Cricket nymphs were reared in proximity to a commercially manufactured Penta-BDE-treated PUF. They accumulated SigmaPBDEs (47+85+99+100+153+154) up to 14,200 mug/kg lipid after 28 days. Non-depurated crickets ingested SigmaPBDE burdens up to 80,600 mug/kg lipid. Owing to the high PBDE content of the PUF (9% by weight) and the fact that much of it likely remained within the polymer matrix, cricket/PUF bioaccumulation factors (BAFs) were on the order of 10-4 to 10-3 for all PBDE congeners. to evaluate real-world biosolid-associated PBDE bioavailability in the soil-associated terrestrial environment, a food web bioaccumulation study was conducted within a Mid-Atlantic US agricultural soil ecosystem receiving long-term (>20 years) sludge amendments. Patterns of those with most intimate contact and reliance on the soil (e.g. earthworms) most closely reflected the soil/biosolid/commercial Penta-BDE fingerprint. PBDEs were BQL in the herbivorous grasshopper, in contrast to the closely related cricket, an omnivorous scavenger. Surprisingly, PBDEs were largely BQL in predaceous wolf spiders regardless of size or trophic level. Penta-BDE constituent biota-soil accumulation factors (BSAFs) ranged from 0.006 (crickets) to 1.2 (earthworms), while BDE-209 BSAFs ranged from 0.07 (earthworms) to 10.5 (millipedes). Lipid and TOC normalized PBDE burdens were strongly correlated for earthworms and ground beetles, perhaps indicative of attainment of steady state accumulation. In general, PBDE burdens decreased in the invertebrates with trophic level at the sludge-amended field. The pattern of carbon (delta13C) and nitrogen (delta 15N) stable isotopes in the taxa sampled suggests different trophic interactions at the non-sludge and sludge-applied fields. However, as only two sites were surveyed, a more exhaustive data set is needed in order to draw more definitive conclusions. Results of these studies provide unequivocal evidence that PBDEs accumulate in soils where biosolids are applied. They also demonstrate that PUF- and biosolid-associated PBDEs are bioavailable and are accumulated to varying degrees by ecologically diverse soil-associated invertebrates. as such, they may become available for uptake by higher order terrestrial consumers, including reptiles, mammals and birds. (Abstract shortened by UMI.).

The potential relationship between riparian arachnids and aquatic insect productivity was assessed in forest streams throughout the central South Island of New Zealand. Initially, a survey was conducted of thirty seven, first-third order forest streams. Streams were selected to represent a range of benthic invertebrate standing crops (as a surrogate measure of "productivity") from Banks Peninsula streams with relatively high benthic invertebrate densities to acid mine drainage streams near Reefton that were almost devoid of aquatic life. At each site benthic invertebrate densities and biomass were measured in riffle habitats and adjacent gravel bars were sampled for terrestrial invertebrates. At a sub-set of 16 sites, a 20 metre longitudinal web-building spider survey was conducted along each bank of the stream. As an additional component, a 20 metre transect starting at the stream margin and running perpendicularly into the forest was used to survey the density of web-building spiders with increasing distance from the stream. Results from the survey of in-situ stream insect biomass and gravel bar invertebrates showed a strong relationship between aquatic insect biomass and the biomass of riparian arachnids (R2 = 0.42, P < 0.001) having accounted for potentially confounding factors such as stream size, elevation, substrate and disturbance. The 20 metre longitudinal survey showed that streams with the highest in-situ insect biomass had significantly higher densities of web-building spiders along their banks (R2 = 0.28, P < 0.05), having accounted for potential confounding variables of elevation, habitat architecture and stream and channel width. The stream to forest survey showed a strong exponential decay in web-building spider densities with increasing distance from the stream (R2 = 0.96, P < 0.0001). Regardless of stream productivity web-building spiders were most abundant at the stream margins and rapidly declined to very low densities 20 metres from the stream. In order to further test the relationship between riparian web-building spider densities and stream insect productivity, a stream fertilization experiment was conducted on six first-second order streams in the Maimai experimental catchment, Reefton. Three streams were enriched by the addition of a fertiliser solution mainly consisting of sodium nitrate for seven months, and the other three streams were used as controls. Water chemistry, benthic invertebrate communities, emerging aquatic adults, and the densities of web-building spiders along the stream corridor and in the forest were monitored in three seasons (spring, summer and autumn) over the course of the nutrient-addition. By the end of the experiment, conductivity was significantly higher in nutrient-addition streams than in the control streams (F = 80.5, P < 0.001), but chlorophyll concentrations showed no significant differences between treatments. Both benthic mayfly densities (F = 6.15, P < 0.05) and the biomass of adult aquatic dipterans (Chironomidae, Simuliidae) (F = 9.25, P < 0.01) were significantly higher in nutrient-addition streams in the last sampling round. Spiders recorded from intercept traps indicated that by the end of the experiment spider activity was significantly higher within 2.5 metres of the nutrient-addition streams (F = 5.70, P < 0.01). However, seasonal densities of web-building spiders along the stream margin and in the forest decreased with no significant differences observed between nutrient-addition and control streams. The results from these studies indicate that adult insects emerging from streams represent an important source of prey that could influence the biomass and abundance of riparian arachnids. Additionally, the results imply that stream productivity and size could mediate the strength of the interaction between riparian and stream habitats. Moreover, feedback mechanisms present in both systems could have implications for such interactions. The elevated densities of web-building spiders observed at the stream margin led to the proposal of the "Highway Robber" hypothesis. This hypothesis suggests that such higher densities of spiders are the result of increased insect activity along the stream corridor: the emergence of adult aquatic insects was predicted to vary less over temporal and spatial scales than that of terrestrial insects due to the poorly synchronized life histories in many New Zealand stream insects. I conclude by suggesting that there are numerous anthropocentric perturbations such as loss of heterogeneity, introduced species, pollution and habitat degradation that could undermine and decouple the intimate linkages between aquatic and terrestrial ecosystems.

Kantzoner längst vattendrag i skogen är en komplex och artrik miljö som är av stor vikt för flertalet arter. Ett stort hot mot kantzoner är skogsindustrin och främst kalavverkning som kan ha en negativ effekt på hela ekosystem. Det finns idag ingen lag som kräver att kantzoner längst vattendrag bevaras med det rekommenderas. En kalavverkning kan minska tillförsel av nedfall som terrestra invertebrater till vattendraget med så mycket som en tredjedel, även om en kantzon på 30 meter bevaras. Tillförsel av terrestra invertebrater till vattendragen är av stor vikt då det kan utgöra upp till 50% av energiintaget hos fisk. Frånvaro av terrestra invertebrater skulle kunna leda till en ökad biomassa av perifyton och en minskad tillväxt hos fisk. För att undersöka om kantzonernas bredd längst vattendrag i skogen påverkar nedfallet av invertebrater till vattendraget genomförs en fältstudie. 17 lokaler har besökts i studien där fällor placerats ut på två ställen längst en 100 meters sträcka. Fällornas innehåll sorterades sedan till ordning. Krontäckningen kontrollerades även på varje lokal och vegetationen inventerades. Regressionsanalys, HCA, PCA och korrelationsanalys utfördes. Efter analys indikerade resultatet på att det är vegetationens sammansättning som är den viktigaste faktorn. Lokaler med mycket örter och bar jord hade en större förekomst av individer och ordningar. Detta kan bero på att ett kalhygge släpper in mer ljus och värme. Avverkade områden kan ha högre näringsvärde vilket kan gynna flertalet arter. Lokalerna som besöktes i studien var förhållandevis ung produktionsskog vilket kan även ha spelat in då dessa skogar har en relativt låg biodiversitet. Vid planering och konstruktion av kantzoner längst skogliga vattendrag bör det prioriteras att skapa kantzoner av god ekologisk status.
Riparian forests is a complex and species-rich environment that is of great importance for many species. A big threat to the riparian forests is the forest industry and mainly clear-cut felling, which can have a negative effect on entire ecosystems. There is currently no law that requires that buffer zones along forest streams be preserved, it is however recommended. A clear cut can reduce the input of to the stream by as much as a third, even if a buffer zone of 30 meters is preserved. The input of terrestrial invertebrates to streams is of great importance as it can account for up to 50% of the energy intake of fish. An absence of terrestrial invertebrates could lead to increased periphyton biomass and reduced growth in fish. A field study was performed to investigate if the buffer width effects the input of terrestrial invertebrates. 17 sites were visited where traps were placed at two placed along a 100 stretch. The content of the traps was then sorted into order. The canopy cover was controlled, and the vegetation was inventoried. Regression analysis, HCA, PCA and correlation analysis was performed. After analysis, the results indicated that it is the composition of the vegetation that is the most important factor. Sites with a lot of herbs and bare soil had a greater presence of individuals and orders. This may be because clear cuts let in mor e light and heat, they can also have a higher nutritional value which can benefit several species. The sites visited in the study were relatively young production forest which also may have played a role as these forests have a relatively low biodiversity. When planning and constructing buffer zones along forest streams, it should be prioritized to creating buffer zones of good ecological status.

In a salinised landscape farm dams may represent the last truly freshwater surface resource, and therefore provide refuge habitats for the biota of wetlands affected by increasing salinity. One wetland threatened by increased salinity in south-west Western Australia is Lake Toolibin. It is listed as a Wetland of International Importance under the Ramsar Convention in recognition of its high conservation value, and remediation actions to halt (and possibly reverse) further increases in salinity are being undertaken at this wetland. Farm dams act as aquatic refugia if they convey resistance and/or resilience to the biotic communities of a disturbed habitat. This study proposed to investigate farm dams as potential refuge habitats from which aquatic macroinvertebrate species could recolonise Lake Toolibin. To do this the physico-chemistry and aquatic macroinvertebrate community of fourteen farm dams surrounding Lake Toolibin, and Lake Walbyring an adjacent wetland that has remained comparatively fresh, were sampled in autumn and spring 1998. Comparison was made to previous studies of Lake Toolibin and Lake Walbyring to detennine if aquatic macroinvcrtebrate species from these wetlands were found in the broader landscape. Results indicate that the aquatic macroinvertebrate communities of Lake Toolibin and Lake Walbyring have been altered by increasing salinity. Both the physico-chemical and aquatic macroinvertebrate data collected from farm dams indicate a high degree of heterogeneity between sites, which is considered to be typical of that throughout the wheatbelt region of Western Australia. Of the 80 aquatic macroinvertebrate taxa previously recorded at Lake Toolibin, 41 were recorded in the surrounding farm dams and 30 from Lake Walbyring, in spring 1998. Of the 38 taxa recorded at Lake Walbyring in spring, 16 were either not collected or were rare in surrounding farm dams at the corresponding time. The aquatic macroinvertebrate community composition of farm dams was dominated by species of Coleoptera, Hemiptera, Chironomidae and Ostracoda. All species recorded from farm dams and Lake Walbyring in 1998 were considered to be freshwater species tolerant of a wide range of salinities, and widely distributed throughout south-west Western Australia. It was concluded that, when considered as a mosaic of habitat types and not as isolated systems, farm dams are important refuge habitats for the aquatic macroinvertebrate species of Lake Toolibin. The farm dams will provide a mechanism for the maintenance of aquatic invertebrate species richness and abundance. Refuge farm dam habitats can therefore contribute to the conservation and management of wetland biodiversity in a salinized landscape such as the Western Australian wheatbelt.

The ground-dwelling invertebrate fauna of medium rainfall jarrah forest was surveyed in three forest blocks (Kingston, Warrup and Winnejup) approximately 25 km north-east of Manjimup in the south-west of Western Australia. Invertebrates were collected by means of pitfall traps on 18 sampling occasions over a period of 22 months (May 1994-March 1996). Approximately 500 000 invertebrates were collected from thirty-five Classes, sub Classes or Orders. The Blattodea, Orthoptera and Araneae were further identified to morphospecies and males and females were distinguished. The forest litter invertebrate community was dominated by Collembola (springtails) (60.8% of total abundance), the Formicidae (ants) (16.8%), Diptera (flies) (6.1%) Coleoptera (beetles) (4.7%) Apocrita (wasps), (2.8%), Araneae (spiders) (2.6%) Acarina (mites) (2.0%) Hemiptera (true bugs) (1.4%) Blattodea (cockroaches) (0.4%) and Orthoptera (crickets and grasshoppers) (0.4%). These accounted for 98% of the total abundance. Of the three taxa identified to morphospecies, spiders were the most diverse, with 31 families and 108 morphospecies present, followed by the grasshoppers and crickets with 3 subfamilies and 67 morphospecies and the cockroaches with 4 families and 32 morphospecies. Six arachnid families (the Actinopidae, Idiopidae, Micropholcommatidae, Nemesiidae, Orsolobidae and Toxopidae) with Gondwanan affinities were present. Marked seasonal trends were present, with overall invertebrate activity (excluding Collembola) highest during spring and lowest during winter. The main factors affecting activity were temperature and rainfall. Changes in the numerical dominance of the taxa occurred between seasons and between years. Marked spatial variability was also evident and appeared to be associated with changes in microclimatic conditions and small-scale spatial variations in habitat. The responses of these invertebrate communities to timber harvesting practices (clearing without post-harvest burn) were examined as part of a larger integrated study (the Kingston Project) conducted by the Western Australian Department of Conservation and Land Management (CALM). A modified BACI (Before/After Control/Impact) design was used. Twenty sites, 8 Internal Controls, 4 External Controls and 8 Impact sites were sampled simultaneously before and after logging. Sampling was undertaken on 8 occasions prior to logging and 10 following logging. Logging occurred between March and April 1995. No significant impacts on total invertebrate abundance and richness were observed after logging. Moreover, only five taxa, Blattodea, Coleoptera, Diptera, Hemiptera and Orthoptera, showed significant changes in abundance, with Blattodea being the most severely affected. Impacts detected by ordination were also of short duration, with post-logging communities resembling those of undisturbed sites after 10 months. Retrospective power analysis revealed that the experimental design used had sufficient power (0.8+) to detect a 30-40% change in total invertebrate abundance. Moreover, the design had power to detect changes of 10-50% for most taxa. Identification of three taxa to morphospecies revealed significant effects of logging, not only on the taxa found to be sensitive to this disturbance (Blattodea and Orthoptera), but also in Araneae, which had shown no impacts at the level of Order. However, for spiders at least, identification to the level of family was preferable to morphospecies as the impacts of logging were masked by environmental noise at those resolutions. The impact of logging on these assemblages was also only of a short duration. Logged sites followed the same seasonal patterns as control sites in the ordination plots, indicating that seasonal and inter-annual climatic changes appear to be more important determinants of community structure and function than a logging event.

Estuarine ecosystems are among the most biologically productive areas and they provide important ecosystem services such as erosion control, habitat and refugia for several species. These environments are characterized by the presence of a variety of organic matter sources due to their transitional position between rivers and the sea. The biotic compositions can undergo spatial and seasonal changes along the estuary due to the spatial and temporal fluctuations of environmental factors such as salinity, temperature and seston loads. Therefore, the different combinations of biotic and abiotic factors make each estuary a unique ecosystem. Because of this spatial and temporal complexity, the understanding of estuarine food web structure and which factors affect the trophic relationships within the ecosystem through space and time represent challenging tasks. Furthermore, estuaries are under an increasing number of anthropogenic perturbations because of the growing concentration of human populations in coastal areas. Knowledge of ecosystem structure and functioning is essential for effective conservation and management planning of coastal areas.In this dissertation, I combine the utilization of biological tracers to examine spatial and temporal variability in the food web structure within a small temperate and microtidal estuary located in South Africa. To this end, fatty acid profiles and stable isotope signatures were measured in several primary organic matter sources and consumers (including zooplankton, fishes and benthic invertebrates) during four consecutive seasons and in three different estuarine regions: upper, middle, and lower reaches. The three reaches had distinct habitat features of vegetation type and morphology, and in particular the lower reaches were colonized by the marsh grass Spartina maritima. Isotopic mixing models were used to estimate the relative contribution of each food source to the diets of invertebrates and fishes within the estuarine food web. The isotopic and fatty acid data showed similar results. In general, the lower reaches of the estuary were characterized by a higher deposition and assimilation by brachyuran crabs of carbon derived from marsh grass detritus, whiletowards the upper reaches a mixture of microphytobenthos and particulate organic matter (phytoplankton and detritus) was deposited and sustained the pelagic and benthic fauna. The highest deposition and assimilation of marsh grass detritus in the lower reaches of the estuary occurred during periods of low freshwater discharge (autumn and winter). In the upper reaches, microphytobenthos and suspended particulate organic matter were dominant basal food resources for the food web during all seasons. These results indicated that benthic consumers incorporated mainly local carbon sources from their local habitat.To clarify isotopic and fatty acid patterns I examined the trophic behaviour of the sesarmid crab Sesarma catenata through laboratory feeding experiments. Results from these experiments validated that decomposed leaves of riparian trees and the salt marsh plant S. maritima were the preferred food of the sesarmid crabs, potentially due to high bacterial loads. The remaining leaf material not assimilated by crabs, together with faecal material, are likely important subsidies for adjacent environments, hence representing an important energy pathway involving the microbial food chain. Furthermore, this dissertation showed the importance of mobile top predators as vectors energetically connecting distinct food chains within the estuary (i.e. littoral, benthic and pelagic). I concluded that a combination of physical (i.e. patterns of freshwater discharge and estuary morphology) and biological factors (i.e. organism feeding behaviour, mobility, primary productivity, the local vegetation type) influence the pattern of dominant primary organic matter sources, and therefore the food web structure along the estuarine environment. In particular, marsh grass detritus contributed substantially to the diets of estuarine fauna during periods of low freshwater discharge. Given the importance of the salt marsh habitat in providing trophic resources, it is important to preserve this environment to sustain the natural biota and ecosystem functioning.

Investigations were made examining the relationships between gastropod species richness and abundance across 20 phosphate and 20 natural lakes in Central Florida. In additional to lake category, age of phosphate lakes was used to determine if phosphate lakes ever approximate natural lakes. Additional physical, chemical, and biological parameters, including chlorophyll a, Ca, secchi, phosphorous, conductance, fish predation, and recreational lake use were investigated in order to determine if they affected gastropods with lake age. Comparisons were also made between gastropod species richness and average abundance and two groups of dominant vegetation categories: Panicum, a structurally complex macrophyte, and Typha, a less structurally complex macrophyte. After phosphate mining operations are completed, Florida state regulations require the establishment of ecologically viable habitat (created lakes) which reflects the properties of regional natural lakes including vegetation structure, littoral zone, bank slope, and lake depth. The littoral zone is part of the mandated structure of the lake, and is of considerable importance to the uptake, storage, transformation and release of nutrients. Within the littoral zone, gastropods are a critical link in the food web with implications for the long term structure and function of a lake. They are known for their close associations with macrophytes and are common environmental indicators since they have limited mobility, high diversity, are well studied, are representative of their habitat type and have a widespread geographic range. They are also an important food sources for many predators in aquatic environments, include migratory waterfowl and game fish. Gastropod species richness and abundance data were collected via standard net sweep methodology. Abundance was presented in catch per unit effort, therefore all abundance data were averages. Initial comparisons between gastropod species richness and average abundance yielded no significant differences between natural and phosphate lakes. However, when age was applied as a covariate, there was a significant difference between lake age as a continuous variable in species richness comparisons. Additionally, categorical comparisons between lakes older or younger than 30 years indicated significantly higher species richness and average abundance of gastropods in lakes phosphate lakes older than 30 years. Physical and chemical properties of the lakes did not appear to influence gastropod populations between lakes of different ages. Fish predation interactions did not indicate any significant influence either. However, the presence of boat ramps did indicate a positive relationship between average gastropod abundance and species richness and recreational lake use. Littoral zone macrophyte comparisons between dominant vegetation Typha and Panicum indicated a significantly positive relationship between gastropod species richness and average abundance in older phosphate lakes dominated by the more structurally complex Panicum macrophytes. Confidence in the Typha and Panicum results was confounded by lack of access to younger, Typha dominated, phosphate lakes. An increase in sample size for younger Typha lakes, with additional site access, may further support these findings.

Haematophagous parasites and disease vectors such as leeches, ticks, mites, lice, bed bugs, mosquitoes, and myiasis-causing fly larvae are common health problems in Lao Peoples Democratic Republic (Lao PDR). A main aim of my field work in Lao PDR in 2006-2010 was to document traditional knowledge among different ethnic groups about plants that people use to repel or to kill blood-feeding invertebrates. We carried out structured interviews in 66 villages comprising 17 ethnic groups, covering a range of ethnic group, throughout Lao PDR and recorded a total of 92 plant species - in 123 different plant-ectoparasite combinations - that are used as traditional repellents and/or as “pesticides” to kill "pest" invertebrates. Traditional use was confirmed in the scientific literature for 74 of these plant species, and for an additional 13 species based on literature on closely related species. We concluded that repellents and pesticides from many plant species are commonly used in the Lao countryside. We also investigated traditionally used Lao plants for their activity to repel or to kill certain disease vectors and parasites. Target organisms were mosquitoes (Diptera, Culicidae), fly larvae (Diptera, Cyclorrhapha) in fermented fish production, and terrestrial blood-sucking leeches (Hirudinea, Haemadipsidae). The potential mosquito repellent activities of essential oils of Croton roxburghii (Euphorbiaceae), Hyptis suaveolens (Lamiaceae), and Litsea cubeba (Lauraceae) were evaluated in the field near Vientiane. Oils at concentrations of 1.7-6.7 µg/cm2 were significantly repellent to Aedes, Armigeres and Culex attracted to human baits. The activities against fly larvae, infesting fermenting fish, of three plant species, Tadehagi triquetrum (Fabaceae), Uraria crinita (Fabaceae) and Bambusa multiplex (Poaceae) were investigated: When fresh material of the plants was added on top of fermenting fish infested with fly larvae significant proportions of the larvae were repelled or killed. The total protective effect, i.e., repellent and killing effect combined, of T. triquetrum, U. crinita, and B. multiplex was 60-83 %, 77-90 %, and 60-93 %, respectively. Field evaluation of the potential leech repellent activities of water extracts of Sapindus rarak (Sapindaceae), Catunaregam spathulifolia (Rubiaceae) and Vernonia elaeagnifolia, (Asteraceae) impregnated on stockings and worn by persons in two leech-infested biotopes revealed leech repellent activities of 82.6%, 62.6% and 63.0%, respectively. The corresponding repellencies of deltamethrin and diethyl-3-methyl-benzamide (DEET) were 73.1% and 88.4%, respectively. Identification of the active components in certain of the plants with the ultimate aim to develop more optimal, less costly repellents, insecticides, acaricides, and anti-leech compounds as alternatives to synthetic repellents and pesticides against blood-feeding insects, ticks, mites, and leeches is in progress.

Effekterna på öringens (Salmo trutta) diet till följd av en avverkning av kantzonsvegetationen har undersökts i ett fältexperiment, där två av de potentiella effekterna av en skogsavverkning simulerades. Fokus låg på de två faktorerna ökad ljusinstrålning och minskat nedfall av terrestra evertebrater. Ökad ljusinstrålning har simulerats med hjälp av montage av lysrör och nedfall av terrestra evertebrater med hjälp av plasttält. Frågeställningarna rör andelen terrester föda i olika behandlingar och årstider, dietskillnader mellan äldre och yngre öringindivider, skillnader i mängden akvatisk föda vid ökad ljusinstrålning samt en taxonomisk översikt av dietens sammansättning. Signifikanta skillnader mellan behandlingarna fanns, där individerna i kontrollbehandlingen åt signifikant mer terrester föda än individer i tältbehandlingen och den kombinerade tält- och ljusbehandlingen. Signifikanta skillnader fanns även mellan provtagningstillfällena där en högre andel terrester föda återfinns senare på säsongen. Inga signifikanta skillnader fanns med avseende på andelen terrester föda mellan äldre och yngre individer, ej heller mellan mängd akvatisk föda mellan de olika behandlingarna. Den akvatiska födan var mer varierad och divers än den terrestra, och daggmaskar (Lumbriculidae) var en mycket vanlig födopartikel.

The effects on the diet of brown trout (Salmo trutta) of a clear cutting of the riparian vegetation has been investigated in a field-experiment, where two of the potential effects of a clear cut were simulated. The focus was placed on the two factors increased light and input of terrestrial invertebrates. The increase of ligth was manipulated by placing fluorescent lights over the brook and the input of terrestrial invertebrates was manipulated by placing plastic tents over the brook. Issues discussed are the percentage terrestrial food in the different treatments and at the different times of sampling, differences in the percentage terrestrial food between older and younger individuals of brown trout, differences in the amount of aquatic food in the light-treatment and a taxonomic summary of the composition of the diet. There were significant differences between the the different treatments, where the individuals in the control treatment ate significantly more terrestrial food as compared to the individuals in the tent and in the combined light and tent treatment. There was also a significant difference between the different times of sampling, more terrestrial food was consumed later in the season. No sigificant differences were detected between older and younger individuals concerning the percentage of terrestrial food eaten, nor between the different treatments concearning the amount of aquatic food consumed. The aquatic food showed a wider variation and was more diverse as compared to the terrestrial food, and earthworms (Lumbriculidae) was a very common food item.

Distúrbios são eventos que modificam os processos e a biodiversidade presentes em um ecossistema. Estas mudanças dão origem a um processo de sucessão ecológica, onde o tempo de retorno a o estado anterior ao distúrbio e chamado de resiliência. Organismos bioindicadores são ferramentas amplamente utilizadas na compreensão destas relações entre os distúrbios e os ecossistemas. Campos são ecossistemas altamente diversos, que podem possuir importante relação com o distúrbio de fogo, sendo este possivel responsável por modelar sua distribuição e propriedades ecológicas. Os artrópodes são componentes importantes da biodiversidade, e possuem respostas rápidas aos distúrbios, características que os tornam ferramentas importantes no monitoramento desta. Dentre estes a ordem Hemiptera é recorrentemente utilizada como bioindicadora de distúrbios, devido ao fato de sua diversidade estar diretamente ligada à diversidade da vegetação onde estes se encontram. Neste estudo explorei as respostas da comunidade de artrópodes ao distúrbio causado pelo fogo, sendo este o tema do primeiro capítulo desta dissertação, e no segundo capítulo, aspectos da diversidade taxonômica e funcional da ordem Hemiptera (Heteroptera e Auchenorryncha) foram utilizados como ferramentas de compreensão dos efeitos do fogo sobre o ecossistema campestre. O experimento de fogo foi conduzido na Estação Experimental Agronômica da UFRGS em Eldorado do Sul. Instalei sete blocos de unidades experimentais, constituídos por duas parcelas de 10 x 10 m, sendo uma delas queimada em dezembro/2009. Realizei amostragens em quatro períodos: antes da queima e um, seis e 12 meses após a queima. Utilizei armadilhas pitfall no solo (cinco por parcela), e rede de varredura na vegetação (quatro transectos em cada parcela). Os artrópodes coletados foram classificados em ordens e contabilizados. Para a ordem Hemiptera classifiquei os adultos em famílias e os jovens em subordem, e para todos os indivíduos medi atributos morfológicos funcionais. No primeiro capítulo conclui-se que a comunidade de artrópodes responde às mudanças ambientais causados pelo fogo, com respostas distintas entre ordens, e entre os níveis da vegetação e sobre o solo. No solo, a resiliência dos artrópodes foi mais lenta do que em artrópodes da vegetação, provavelmente devido à reconstituição da camada de serrapilheira acontecer posteriormente à regeneração da vegetação, através da deposição de matéria orgânica morta. No segundo capítulo concluo que os efeitos do fogo sobre a vegetação campestre afetaram a comunidade de Hemiptera aumentando a abundância e diversidade deste grupo, padrão este que segue a diversificação da vegetação. Quanto aos atributos, o principal atributo selecionado foi aparelho sugador maior nas áreas queimadas. O período de desenvolvimento em que os organismos se encontram, adulto ou imaturo, parece ter sido mais fortemente selecionado pelas alterações do fogo.
Disturbances are events that modify processes and biodiversity present in an ecosystem. These changes lead to an ecological succession process, where the time to return to pre-disturbance state is called resilience. Bioindicators are tools widely used to understand these relationships between disturbances and ecosystems. Grasslands are highly diverse ecosystems and fire disturbance is an important factor there, responsible for shaping their distribution and ecological properties. Arthropods are key biodiversity components, and have fast responses to disturbances. These characteristics make them important tools for biodiversity monitoring. Among arthropods, the order Hemiptera is recurrently used as a bioindicators of disturbance, because their diversity is directly linked to vegetation diversity. This study explored the effects of fire on the arthropod community, which is the theme of the first chapter of this dissertation, and in the second chapter, aspects of taxonomic and functional diversity of the order Hemiptera (Heteroptera and Auchenorryncha) were used to understand the fire effects on the grasslands. Fire experiment was conducted at Estação Agronômica Experimental da UFRGS in Eldorado do Sul. I installed seven blocks of experimental units (two plots of 10 x 10 m) and one plot of each were burned in December 2009. Samplings occurred in four periods: before fire and one, six and 12 months after fire. I used pitfall traps in the soil (five per plot), and in vegetation we use sweep net (four transects in each plot). Arthropods collected were identified into orders. I classified the order Hemiptera adults in families and the young in suborders, and for each individual i measured functional morphological attributes. From the first chapter we conclude that the arthropod assemblage responds to environmental changes caused by fire, with distinct responses among arthropod orders and between the vegetation and ground levels. On the ground, arthropod community resilience is slower than for vegetation arthropods, probably due to a delay in the comeback of the litter soil layer which is subsequent to the regeneration of the vegetation, through deposition of dead organic matter. In the second chapter I conclude that the effects caused by fire affected the Hemiptera community, increasing abundance and diversity of this group. For functional attributes, the sucking apparatus was selected most in burned areas. The developmental period of the organisms, either adult or immature, seems to have been more strongly selected by fire-induced changes.

Despite dramatic morphological differences between animals from different taxa, several important features in organization and sensory system processing are similar across animals. Because of this similarity, a number of different organisms including mammals, insects, and decapod crustaceans serve as valuable model systems for understanding general principles of environmental effects. This research examines intrinsic and extrinsic factors by behaviorally and physiologically means to identify the impact of environmental conditions on two distinct crayfish species- Procambarus clarkii (surface) and Orconectes australis packardi (cave). The research identified behavioral and physiological responses in these two morphological and genetically distinct species. The studies also examined multiple levels of complexity including social behavior, an autonomic response, chemosensory capabilities and neuronal communication, identified comparative similarities/differences, addressed learning and environmental influences on learning and examined behavioral and cellular responses to high levels of carbon dioxide. I found environmental factors directly influence crayfish behavior of social interactions. Interactions were more aggressive, more intense and more likely to end with a physical confrontation when they took place 'in water' than 'out of water'. The modified social interaction resulted in a altered fighting strategy. A study on motor task learning was undertaken which showed similar learning trends among these crayfish species despite their reliance on different sensory modalities. I also demonstrated learning was dependent on perceived stress by the organism. Previously trained crayfish inhibited from completing a task showed significant increase in an autonomic stress response. Studies on the behavioral and physiological responses to CO2 revealed that high [CO2] is a repellent in a concentration dependent manner. The autonomic responses in heart rate and an escape tailflip reflex shows complete cessation with high [CO2]. A mechanistic effect of CO2 is by blocking glutamate receptors at the neuromuscular junction and through inhibition of the motor nerve within the CNS.

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Invertebrados terrestres podem ser empregados como biomonitores para a avaliação da qualidade ambiental de áreas urbanas devido à capacidade de absorver substâncias químicas do ambiente por meio da alimentação ou contato direto. Ainda são poucos os estudos realizados utilizando insetos como biomonitores, mesmo sendo bastante relevantes ao considerar seu papel ecológico e densidade populacional elevada. Este trabalho foi realizado com o intuito de utilizar invertebrados terrestres como biomonitores nas áreas urbanas Manguezal Memorial Arcoverde, Reserva da Mata do Frio e Campus Tecnológico do Nordeste, todas localizadas em Pernambuco. Para fins de monitoração de impactos ambientais, foram utilizados padrões de referência para estudos ambientais da classe Insecta obtidos no Refúgio Ecológico Charles Darwin, Igarassu, Pernambuco, unidade conservação com maior grau de conservação. A coleta dos invertebrados para realização do estudo foi executada utilizando-se armadilhas com iscas de mel, laranja, sardinha e carne putrefata a fim de atrair animais com diferentes hábitos alimentares. Após a coleta, os invertebrados foram lavados e em seguida, separados em nível de ordem para realização das análises químicas. A maior diversidade de ordens de invertebrados terrestres foi encontrada na Reserva da Mata do Frio, enquanto a ordem mais abundante coletada nas áreas urbanas estudadas foi Hymenoptera. Porções-teste de 0,1 g de massa seca foram analisadas por Espectrometria de Fluorescência de Raios-X por Dispersão de Energia (EDXRF), Espectrometria de Massas com Plasma Indutivamente Acoplado (ICP-MS) e Absorção Atômica por Forno de Grafite (GFAAS). A qualidade do procedimento analítico foi avaliada utilizando-se de porções-teste dos materiais de referência SRM 2976, SRM 8414, SRM 8415 e IAEA 336. As técnicas analíticas empregadas permitiram a determinação da concentração dos elementos químicos As, Cd, Cl, Co, Cr, Cu, Fe, K, Mo, P, Pb, S, Sb, Th, U e Zn nos invertebrados das áreas urbanas estudadas. O manguezal Parque Memorial Arcoverde apresentou maiores características de ambiente impactado, devido às elevadas concentrações de Cd, Co, Cu, Mo, S, Sb e Zn nos invertebrados analisados. Na Reserva da Mata do Frio, foram obtidas concentrações superiores dos elementos químicos Cl, Cu, K e Zn, enquanto que, no Campus Tecnológico do Nordeste, o elemento químico Cd se destacou por apresentar concentração superior a faixa esperada em amostras de Hymenoptera. Considerando a relativa facilidade de coleta e análise, diversos ecossistemas puderam ser avaliados convenientemente utilizando invertebrados terrestres.
Terrestrial invertebrates can be employed as biomonitors for the environmental quality assessment in urban areas due to the ability of uptake of chemical substances through food or direct contact. Moreover, there are few studies using insects as biomonitors, even though their relevance owing to their ecological role and high population density. This work has utilized terrestrial invertebrates as biomonitors in the urban areas Parque Memorial Arcoverde, Reserva da Mata do Frio and Campus Tecnológico do Nordeste, located in the Pernambuco State, Brazil. Reference standards for environmental studies of class Insecta obtained in the Refúgio Ecológico Charles Darwin, Igarassu, Pernambuco, Brazil, a conservation unit of high conservation level, were used for environmental impact monitoring purposes. Invertebrates were sampled by using traps with honey, orange, sardine and rotten meat as attractive for animals of different food habits. After, the invertebrates were washed and then separated at the order level in order to analyze the chemical elements. The greatest diversity of orders was found in the Reserva da Mata do Frio, while the most abundant order in the studied urban areas was Hymenoptera. Test portions of 0.1 g were analyzed by Energy Dispersive X-Ray Fluorescence Spectroscopy (EDXRF), Inductively Coupled Plasma Mass Spectrometry (ICPMS) and Graphite Furnace Atomic Absorption (GFAAS). The quality of the analytical procedure was evaluated using the reference materials SRM 2976, SRM 8414, 8415 and IAEA 336. The analytical techniques employed here allowed the determination of As, Cd, Cl, Co, Cr, Cu, Fe, K, Mo, P, Pb, S, Sb, Th, U and Zn in the invertebrates from the studied urban areas. The Parque Memorial Arcoverde mangrove was considered one of the most impacted areas according to the high concentrations of Co, Cu, Mo, S, Sb and Zn determined in the invertebrates. For the Reserva Mata do Frio, it was observed the highest concentrations of the chemical elements Cl, Cu, K and Zn, while one invertebrate sample from the Campus Tecnológico do Nordeste accumulated Cd above the expected range. Considering the relative facility of sampling and analysis, diverse ecosystems could be appropriately assessed by means of terrestrial invertebrates.

Riparian vegetation along streams and rivers affects the aquatic community in numerous ways and often operates as a link for energy flux between forest and streams. The studies presented in this licentiate thesis focus on light and terrestrial invertebrates, two factors influenced by riparian zone structure, which potentially affect stream ecosystems and thus also brown trout (Salmo trutta). Paper I is a laboratory experiment where I study size dependent foraging behavior on surface-drifting terrestrial invertebrates and benthic invertebrates by brown trout. The results show a size-dependent difference in foraging ability with large trout being better able to use terrestrial surface prey than small trout. I argue that such ontogenetic foraging differences are due to both morphological constraints (eg. gape limitation) and size dependent behavioral differences related to predation risk. Paper II consists of a 5 month-long 2x2 factorial design field experiment where my objective was to examine the effects of terrestrial invertebrate input and solar radiation (PAR) on different trophic levels in a boreal headwater stream. More specifically, I followed the effects of increased light and decreased terrestrial invertebrate subsidies on periphyton, benthic macroinvertebrates and two size classes of the top fish predator, brown trout. The results showed that the reduction of terrestrial invertebrate input had size- and seasonal-dependent effects on trout, where large trout had lower growth rates than small trout, mainly in summer. Diet analyses of trout supported growth differences in that large trout in unmanipulated enclosures consumed relatively more terrestrial prey than large trout living in enclosures with reduced terrestrial inputs. A higher reliance on terrestrial prey subsidies by large trout compared to small may be explained by ontogenetic differences in foraging and habitat choice. Despite a 2.5-fold increase in PAR, light did not have an effect on chlorophyll a biomass, nor was there an effect on the density or composition of benthic macroinvertebrates. The lack of effects on primary production may be explained by very low nutrient levels in the stream.

Created lakes are an end product of phosphate mining in Florida. Beginning in 1975, Florida reclamation rules set criteria for phosphate created lakes aiming to approximate the structure of natural lakes, and emphasizing extensive littoral zones with both emergent and submersed vegetation. Lake development relative to lake age and design were examined for 22 phosphate lakes representing a 40-year age trajectory, utilizing water quality and benthic invertebrate communities from littoral and deep-water locations (Chapter 1). The relative importance of morphometry and lake age in the development of littoral plant communities was examined using multiple vegetation surveys throughout the year, in a separate investigation of 39 littoral locations from 13 lakes reflecting age and morphometry gradients (Chapter 2). The same littoral locations were used to investigate benthic community composition in relation to emergent and submersed plant habitats (depth of 0.5 m and 1.5 m respectively), water quality, sediment characteristics, morphometry and lake age (Chapter 3). Phosphate lakes >5.5m deep are warm monomictic water bodies, stratifying from April to October/November, and developing thermoclines at approximately 4 m. Shallow lakes (<5.5 m deep) are polymictic. Phosphate lakes become eutrophic or hypertrophic immediately after creation and remain so through time. Unlike reservoirs, they do not go through a trophic surge, which is an initial period of great productivity that declines as sediment nutrient storage is exhausted. Among the 22 sampled lakes, epilimnetic physical and chemical water quality variables (Secchi depth, chlorophyll a, turbidity, pH) did not differ along the age trajectory. Only specific conductance declined significantly, 10-20 years after lake creation, most probably due to bank stabilization. All water quality variables were within the range of natural lakes in the region, and were most similar to urban rather than suburban or rural natural lakes. Benthic invertebrate abundance (total, Chironomidae, Oligochaeta, invertebrates other than Chironomidae and Oligochaeta) and taxa richness displayed great variability with lake age and did not differ among decadal lake groups at any depths examined (1 m, deepest point). Invertebrate abundance did not differ between littoral and deep habitats, except for lakes >10 years old, where littoral abundance was greater than deep-water abundace, suggesting faster colonization of the littoral zone. Littoral taxa richness was greater than richness in deep-water, which was attributed to taxa other than Chironomidae and Oligochaeta. Deep-water and most littoral habitats were dominated by Chironomidae, whereas Oligochaeta were occasionally dominant in the littoral zone. Dissolved oxygen was the variable explaining most variance of both littoral abundance and richness. Littoral macrophyte communities in phosphate lakes differed from natural Florida lakes. Although most phosphate lakes developed emergent littoral zones, submersed vegetation was absent, with few exceptions of the non-indigenous Hydrilla verticillata. Plants clustered in groups reflecting their hydrological designations. Frequently encountered plants classified either in the obligate wetland plant group, characterized by Typha, and inhabiting mostly intermediate-age lakes or the facultative wetland plant group, characterized by Panicum repens. Most plants in the latter group were bimodally distributed in youngest and oldest lakes, whereas few plants were ubiquitous. Littoral plant community composition was determined by both lake morphology and age, but the relative influence of these two components was not clear. Littoral plant composition was a good predictor of lake development. Morphometric (slope) and sediment characteristics (organic content, particle size) did not differ between the two littoral depths examined (0.5 m and 1.5 m). Slope correlated moderately but significantly with lake age, and organic content was low in all samples. Total littoral benthic invertebrate abundance and its major component Chironomidae, started from low values at newly created lakes and remained low or increased unpredictably with time. Total, Chironomidae, Oligochaeta and Gastropoda abundances did not differ between the depths of 0.5 m and 1.5 m, whereas taxa richness and the abundance of invertebrates other than Chironomidae, Oligochaeta, and Gastropoda was greater at the shallower depth (0.5 m).The relative effect of lake morphology versus age on benthic invertebrate composition was not clear. Total and Chironomidae abundance increased with lake age at 0.5 m, and bank slope at 1.5 m. Both littoral invertebrate abundance and richness in phosphate lakes were lower than in a natural, mesotrophic, macrophyte-dominated lake in the region, characterized by great Oligochaeta densities.

Minimising the potential impact of forest management requires an understanding of the key elements that maintain forest diversity and its role in ecological processes. Invertebrates are the most diverse of all biota and play important roles in maintaining forest processes. However, little is known about invertebrates in New Zealand's beech forests or the degree to which selective beech harvest might impact on their diversity and ability to carry out ecosystem processes. Studying ecosystem responses to disturbance is considered vital for understanding how ecosystems are maintained. One of the main objectives of this research was to assess whether litter-dwelling invertebrates were susceptible to the impacts of selective harvest and, if so, whether they could be used as indicators of forest health. Changes in invertebrate diversity could have important implications for nutrient cycling and primary production in forests. Litter-dwelling invertebrates contribute to the process of decomposition by increasing the surface area of the leaves, mixing soil organic matter and by infecting leaf particles with soil microbes. This investigation into the function of invertebrates in beech forest was carried out in the context of ecological theories which relate diversity to ecosystem stability and resilience. A replicated study was established in Maruia State Forest (South Island, New Zealand) to assess the potential biotic and abiotic impacts of sustainable beech harvest. Litter-dwelling invertebrates and environmental factors were monitored during 1997, before harvest, to determine how much variability there was between study sites. Specifically, litter pH, light intensity, litter fall, litter temperature, moisture as well as invertebrate abundance and diversity were compared before and after selective harvest. On 17 January 1998, two to three trees were selectively harvested from three of the nine study sites. On 15 February 1998 a similar number of trees were winched over or felled manually to create artificial windthrow sites. The remaining three undisturbed sites were used as controls. Invertebrates belonging to the detritivore guild were assessed from litter samples and a series of litter-bags containing pre-weighed leaf litter which were placed in each of the sites to assess rates of litter decomposition. Millipedes (Diplopoda: Polyzoniidae, Schedotrigonidae, Dalodesmidae, Habrodesmidae, Sphaerotheridae), earthworms (Oligochaeta: Annelida), tipulid larvae (Diptera: Tipulidae), weevils (Coleoptera: Curculionidae), moth larvae (Lepidoptera: Oecophoridae, Tortricidae and Psychidae), slaters (Isopoda: Styloniscidae), Oribatid mites (Acarina: Cryptostigmata) and landhoppers (Crustacea: Amphipoda) were extracted from the litter-bags and their abundance and diversity was compared between the three treatments. Weight loss from the litter-bags and the carbon and nitrogen content of litter were used to measure the rate of decomposition in each treatment. An additional study investigated whether exclusion of invertebrates from leaf litter resulted in reduced rates of decomposition. The results indicated that there was an increase in light intensity and a small increase in temperature following selective harvest and artificial windthrow. There was no significant difference in litter moisture or the amount of litter fall between the treatments. Invertebrate abundances were significantly affected by season but did not appear to be affected by selective harvest or artificial windthrow. The diversity of invertebrates remained relatively constant throughout the year, as did the rate of decomposition. When invertebrates were excluded from the leaf litter there was no consequential effect on the rate of litter decomposition. This suggests that there may be compensatory mechanisms taking place between the trophic levels of the food web to maintain processes and that direct links between invertebrates and decomposition are relatively weak. In conclusion, it appears that the effects of selective beech harvest on forest-floor processes were minimal and are comparable to those created by natural windthrow disturbance. It also appears that macroclimatic effects such as seasonal climatic effects have a large effect on forest biota. As none of the invertebrates studied appeared to be detrimentally affected by selective harvest and as there was no direct link demonstrated with decomposition, it was considered inappropriate to advocate the use of this group of invertebrates as indicators of sustainable forest management. The results from this study provide information which may help inform decisions on the future management of diversity in beech forest ecosystems.

Existe uma necessidade urgente em monitorar as respostas da biodiversidade e dos processos ecológicos a distúrbios e mudanças no uso da terra. Diversos estudos tem indicado que o uso da abordagem funcional da biodiversidade, baseada em atributos funcionais, facilita a compreensão sobre a organização dos organismos nas comunidades, da funcionalidade dos ecossistemas, e desta forma, auxilia na identificação das suas relações com fatores ambientais. No primeiro capítulo desta tese eu apresento o arcabouço teórico da ecologia funcional aplicada ao estudo dos invertebrados terrestres, e reviso o que são atributos funcionais, como usá-los na descrição e monitoramento das comunidades e o porquê, ressaltando a ligação dos invertebrados com processos ecológicos. Nos próximos capítulos eu apresento estudos experimentais avaliando as respostas funcionais de dois grupos de invertebrados - aranhas (Araneae) e tripes (Thysanoptera) - e de processos ecológicos influenciados por invertebrados (detritivoria e decomposição de serapilheira) ao distúrbio por fogo nos Campos Sulinos. As queimadas representam uma estratégia de manejo frequente nas pastagens naturais do RS, e carecem em estudos avaliando seus efeitos no ambiente, biodiversidade e processos. A investigação foi realizada com base em um experimento de queima controlada na Estação Agronômica da UFRGS, em Eldorado do Sul, RS. O design foi em blocos casualizados, com 14 parcelas experimentais de 10 x 10 m pareadas; sendo uma parcela de cada bloco queimada no final da primavera de 2009, e a outra, considerada como controle. Informações sobre invertebrados, processos ecológicos e propriedades abióticas do hábitat foram obtidas em todas parcelas antes do fogo (para a caracterização inicial), e 1 mês, 6-7 meses e 12 meses após o fogo. Para o estudo de caso com aranhas, eu classifiquei as comunidades em famílias, atributos de estratégias de caça e medi todos os indivíduos (1755) em atributos funcionais morfológicos, sendo incorporada toda a variabilidade intra e interespecífica, e fenológica das comunidades. Por outro lado, no estudo de caso com tripes, descrevi atributos funcionais (hábitos alimentares, requerimentos de hábitat e atributos morfológicos) por espécie de tripes (48 spp.), assumindo que a variação nos atributos funcionais é sempre maior entre espécies do que dentro da mesma espécie. Nos dois estudos de caso, eu encontrei padrões indicativos de filtragem ambiental, ou seja, o fogo e/ou as mudanças no hábitat induzidas pelo fogo, parecem ter atuado como um filtro, selecionando organismos com determinado conjunto de atributos em detrimento de outros. Esses padrões foram dependentes do período após a queima considerado, por exemplo: um mês após o fogo aranhas construtoras de teias irregulares e tripes fungívoros foram prejudicados, enquanto que aranhas caçadoras da vegetação, com grandes quelíceras, tripes fitófagos e associados com gramíneas aumentaram suas proporções. Para aranhas ainda verifiquei convergência de atributos ao gradiente de biomassa induzido pelo fogo (filtragem ambiental), e divergência de atributos ao gradiente de heterogeneidade da vegetação, indicativo de limitação de similaridade (i.e. aumento da coexistência de organismos funcionalmente diferentes e diminuição de competição). Finalmente com relação aos processos ecológicos, encontrei correlações interessantes acerca de seus agentes modeladores, e.g. entre a atividade de detritivoria com a decomposição de serapilheira, e desta com a equidade da vegetação em campo não queimado. Também mostro que os processos são sensíveis, mas resilientes, ao distúrbio por fogo, seguindo a recuperação da estrutura de hábitat. Adicionalmente, eu incorporei à tese um capítulo sobre uma técnica para avaliar o processo de detritivoria, denominado bait-lamina test, o qual avalia diretamente as taxas de alimentação de invertebrados detritívoros do solo. Neste estudo pioneiro nos campos do RS, esclareço alguns aspectos metodológicos que possam constituir uma base para futuras pesquisas. Contudo, com esta tese espero estar contribuindo com o conhecimento sobre as respostas das comunidades de invertebrados e dos processos ecológicos ao distúrbio por fogo nos Campos Sulinos. Em geral, posso concluir que a abordagem funcional trouxe muitos benefícios ao monitoramento da biodiversidade, e que há elevada resiliência das assembléias de aranhas e tripes, e dos processos de detritivoria e decomposição às queimadas de pequena escala nos campos.
There is a huge need of monitoring the responses of biodiversity and ecological processes to disturbances and land use changes. Several studies have indicated that the functional approach of biodiversity, based on functional traits, facilitates the understanding of community assembly and ecosystem functionality, and thus assists on the identification of their relationships with environmental factors. In the first chapter of this Thesis I present the functional ecology theory applied to studies on terrestrial invertebrates, and I review what functional traits are, how to use them in community description and monitoring, and why, highlighting the connections between invertebrates and ecological processes. In the following chapters I present experimental studies evaluating the functional responses of two invertebrate groups- spiders (Araneae) and thrips (Thysanoptera) – and ecological processes influenced by invertebrates (detritivory and litter decay) to fire disturbance in Campos grasslands. Burning represents a common strategy for pasture management in Rio Grande do Sul State, and there is a lack of studies regarding their effects on the environment, biodiversity and processes. Our investigation was performed based in a burning experiment at Estação Agronômica of UFRGS, Eldorado do Sul, RS. The design was blocked, with 14 experimental paired plots of 10 x 10 m. One plot from each block was burned at the end of spring 2009, and the other is considered a control plot. Information concerning invertebrates, ecological processes and abiotic habitat proprieties were obtained from all plots before fire (initial characterization) and 1 month, 6-7 months and 12 months after fire. For the spider study case, I classified the organisms in families, feeding strategy traits, and measured all spider individuals (1755) thus incorporating all intra and interspecific variability of the communities. On the other hand, in the thrips study case I described functional traits (feeding habits, habitat requirements, and morphological traits) per species (48 spp.), assuming that the variation on functional traits should be higher between species than within species. In both cases, I found patterns indicating environmental filtering, which means that fire and/or the fire-induced habitat changes acted as a filter, sorting organisms with a determined group of traits instead of others. These patterns were dependent on the period after fire considered. For example, one month after fire irregular web spider builders and fungivorous thrips were more uncommon than expected, while vegetation hunter spiders, with large chelicerae, and leaf feeder thrips and thrips associated to grasses increased their proportions. For spiders we also verified a trait-convergence pattern along the plant biomass gradient induced by fire (environmental filtering), and trait-divergence pattern along the vegetation heterogeneity gradient indicating limiting similarity (i.e. increase in coexistence of functionally different organisms, and reduction of competition). Finally, regarding ecological processes, I found interesting correlations on their drivers, e.g. between detritivory and litter decay, and between these with plant evenness in unburned grasslands. Also, I show that ecological processes are sensitive but resilient to fire, following habitat structure recovery. Additionally, I incorporate to the Thesis a methodology chapter about the bait-lamina test, which evaluates the feeding rates of soil detritivore invertebrates directly. In this pioneer study, I clarify some methodological aspects of measuring invertebrate detritivory that could help future research. Nevertheless, with this Thesis I hope to contribute to the understanding of invertebrate community and ecological processes responses to fire disturbance in South Brazilian grasslands. Overall, I can conclude that a functional approach brings many benefits to biodiversity monitoring, and also that spiders and thrips communities, and detritivory and decomposition processes are very resilient to the change brought by small scale grassland burning.

Le cycle des metastrongles comprend trois phases: - l'adulte vivant dans les poumons de sangliers, le degre d'infestation est fonction de l'age de l'hote; - les oeufs sont disperses par les feces des sangliers, l'expulsion des oeufs subit des variations saisonnieres; - les larves vivant dans les hotes intermediaires, les lombrics

Patterns of site occupancy among boreal stream insects were studied in central Sweden with focus on sparsely distributed species and the role of dispersal and niche limitations.

In the study of dispersal limitation, I found that effects of an extraordinarily harsh winter in small to medium-sized streams were strongest in sites located in small streams and far from lake outlets. Species richness and the total abundance of macroinvertebrates and trout returned to pre-disturbance levels after three years. However, some species showed slow recolonization and the proportion of holoaquatic taxa was still reduced after three years. In a second study, I found a positive correlation between site occupancy in stream caddisflies and morphological traits associated with fast and energy-efficient flight, whereas specialized spring caddisflies showed a negative correlation to these traits compared to stream species. This suggested that streams, but not springs, select for strong dispersal ability in caddisflies. In a survey of springs in central Sweden, hydrogeology was found to be a useful predictor of the occurrence of spring specialists. Two of these, Crunoecia irrorata Curtis and Parachiona picicornis (Pictet), were found exclusively in glaciofluvial springs, characterized by a stable discharge and temperature. Less specialized members of the spring fauna (i.e. species also occurring in streams, ponds or lakes) also occurred in moraine and limestone springs characterized by more unstable conditions.

Niche limitations were studied by contrasting large-scale distributions of closely related rare and common stoneflies. Differences in temperature requirements in the juvenile stages and life cycles suggested that the rare species, Isogenus nubecula Newman, was restricted by a limited tolerance to low stream temperatures, whereas the two common species, Isoperla grammatica (Poda) and Diura nanseni (Kempny), appeared to have a broader tolerance to climatic conditions in the study area. In a second study of niche limitations, macroinvertebrate assemblages in 88 streams in Central Sweden showed a nested distribution pattern. Most species deviating from expected distributions occurred in small streams, indicating competitive exclusion from species-rich sites, predator avoidance, or specialization to unique habitat features of small streams. In the last paper, the longitudinal distribution of filter-feeding caddisflies in a lake-outlet stream demonstrated patterns concordant to feeding specialization.

As a species domesticated only in the last century, agricultural cranberry plants (Vaccinium macrocarpon) remain little removed from their wild relatives. Thus, it is a potential model species for studies of the earliest stages of domestication; however, there is little available quantitative information on its wild population biology and ecology. As such information is vital to studies of the ecological changes occurring during domestication, the purpose of this study was to consolidate the relevant knowledge available and conduct a preliminary search for patterns in the invertebrate communities of wild bogs. The alpha diversity was found to be greater than the overall (gamma diversity), which is likely a result of the metric used and the fact that there was minimal overlap in rare species between bogs. In addition, alpha diversity was found to be significantly negatively correlated with bog age. Two pairs of species were found to be correlated with each other, Blunt-nosed (Limotettix vaccinia (Van Duzee)) and Sharp-nosed leafhopper (Scaphytopius sp.), along with fleabeetle (Sysena frontalis (F.)) and firebeetle (Cryptocephalus incertus (Oliv.). In addition, it was found that spiders are significantly more common in western bogs, while firebeetle is significantly more common in eastern bogs. However, this may be indicative of a correlation with bog age rather than a true correlation with geographic location. More work is needed to determine the true dynamics driving these findings, so that the information could eventually be used to improve the efficacy and decrease the environmental impact of pest management on agricultural bogs.

Till today, the expectations for the international market of engineered nanomaterials (NMs) are a continuous exponential grow. This is partly due to the number of applications that continues to increase. Inevitably this usage poses a risk for humans and the environment. The terrestrial compartment is at particular risk due to the presence of these materials in biosolids, remaining as a sink. Over the last decades progress has been made to improve the knowledge of NMs hazard and environmental risk assessment (ERA). Overall from the research made it was clear that results provided by most standard tests, that covered short term effects were not enough to evaluate effects of NMs. Hence data from long term exposures was urgently needed. Multigenerational exposures were highly recommended once they can provide information on post-generational and transgenerational effects. On the other hand, there was a continuously increase in the number of evidences that NMs can affect epigenetic mechanisms, and that epigenetics could help to explain multigenerational effects. So, epigenetics came as an important tool to include on the evaluation of NMs hazard and ERA. The aim of this thesis was to develop new ecotoxicity assays for the soil invertebrate standard model species Enchytraeus crypticus, to evaluate long term effects of NMs. Further it was aimed to investigate epigenetic effects, and other stress responses at different levels of biological organization, incurring from the long term exposures to NMs. Finally, it was intended to integrate all the data and build onto an adverse outcome pathway (AOP) framework. To cover long term effects, full life cycle (FLC) and multigenerational (MG) tests were developed for E. crypticus. Organisms were exposed to silver (Ag) NMs, coper oxide (CuO) NMs, Nanostructured Tungsten Carbide Cobalt (WCCo) and the corresponding ionic forms (for comparison). FLC exposures showed life stage effects which were specific for the NMs in relation to the ionic form. MG exposures showed different organisms´ responses between NMs and the ionic form, however for both forms there was transference of effects to subsequent exposed generations and unexposed generations, indicating transgenerational effects. Moreover, evaluation of epigenetic toxicity from these MG exposures was positive for both NMs and ionic form. Finally the integration of (eco)toxicoepigenetics data, at the several levels of biological organization, into the AOP framework proved to be very useful to distinguish different molecular initiating and key events, between NMs and the ionic form. In sum the research done during this thesis provided a stepping stone for the long term assessment effects of NMs in soil, and for the inclusion of evaluation of epigenetics in soil ecotoxicology.
Ainda nos dias de hoje as expectativas para o mercado internacional de nanomateriais (NMs) projectados é de um crescimento exponencial contínuo. Isto é em parte devido ao facto de que o número de aplicações para estes NMs continua a crescer. Inevitavelmente este uso acarreta risco para o ser humano e para o ambiente. Para o ambiente terrestre existe um risco acrescido devido á presença destes materiais em biossólidos, que permanecem como uma fonte de NMs. Nas últimas décadas tem-se feito progressos no sentido de melhorar o conhecimento sobre o perigo dos NMs e a avaliação do risco ambiental. Sobre a investigação realizada até então ficou claro que os resultados fornecidos pelos testes padrão, que incluíam efeitos de curta duração, não eram suficientes para avaliar os efeitos dos NMs. Assim sendo, dados sobre exposições de longa duração eram necessários urgentemente. Exposições multigeracionais eram particularmente recomendadas, uma vez que fornecem informação sobre os efeitos nas pósgerações e efeitos transgeracionais. Por outro lado, existia um aumento contínuo sobre o número de evidências que reportavam que os NMs podem afectar mecanismos de epigenética, ao mesmo tempo, a epigenética poderia ajudar a explicar os efeitos multigeracionais. Assim, a epigenética tornou-se uma ferramenta importante a incluir na avaliação do perigo e do risco ambiental dos NMs. O objectivo desta tese foi desenvolver novos ensaios de ecotoxicidade para o invertebrado de solo Enchytraeus crypticus, que é uma espécie modelo padronizada, para avaliar efeitos de longa duração dos NMs. Para além disso, tinha-se como objectivo investigar efeitos de epigenética e outras respostas gerais de stresse, nos diferentes níveis de organização biológica, que decorriam destas exposições de longa duração aos NMs. Finalmente pretendia-se também integrar todos os dados no formato de via metabólica adversa (VMA). Para a inclusão de efeitos de longa duração, testes de ciclo de vida completo (CVC) e multigeracionais (MG) foram desenvolvidos para o E. crypticus. Os organismos foram expostos a NMs de prata (Ag), NMs de óxido de cobre (CuO), carboneto de tungsténio e cobalto (WCCo) nanoestruturado e os correspondentes compostos na forma iónica (para comparação). As exposições de CVC mostraram efeitos específicos para os NMs em relação á sua forma iónica. As exposições MG mostraram diferentes respostas dos organismos para os NMs em relação á sua forma iónica, contudo para ambas as formas houve uma transferência de efeitos para as subsequentes gerações expostas e gerações não expostas, estas indicando efeitos transgeracionais. Para além disso, a avaliação da toxicidade epigenética nestas exposições MG foi positiva para os NMs e respectiva forma iónica. Finalmente a integração dos dados de (eco)toxicoepigenética, nos diferentes níveis de organização biológica, no formato de VMA, provou ser muito útil para distinguir entre NMs e a forma iónica, eventos moleculares e eventos chave. Em suma a investigação feita durante esta tese providenciou um suporte importante para a avaliação de efeitos de longa duração dos NMs no solo e, para a inclusão da avaliação epigenética na ecotoxicologia de solo.
Programa Doutoral em Biologia

Advances in farming technology, and the variety of modern agricultural practices, have the potential to reduce, maintain or improve biodiversity in an agricultural landscape. Environmentally sensitive farming systems are becoming more important on a local level, as climate change, declining biodiversity and habitat fragmentation impact the environment at a landscape scale. Invertebrates are important components of an agricultural landscape, playing numerous roles including pest control, plant protection, pollination, and carbon cycling. They are also an important food source for many reptiles, birds, mammals and other insects, making them a key component of the food chain. Ants in particular are useful tools in biodiversity monitoring as they are abundant in both disturbed and intact habitats, and their many functional groups help to illustrate their community structure at a given point in time. For these reasons, they can be used to demonstrate the short and long term impacts of land management in various environments, including rehabilitated mine sites, fire affected regions, and agricultural landscapes. Conducted on working farms, this study looked specifically at insect in the agricultural landscape, using 10 sheep pastures which have been restored with eucalypt plantings. Looking at species richness, relative abundance, and community structure, this study assessed the ant and beetle communities in these plantings and compares these to pasture control sites and nearby remnant woodland patch control sites. The influences of elevation, ground cover, soil clay, patch size, and age of planting were tested using regression analyses. It was found that leaf litter cover and weediness have a significant influence on invertebrate recolonisation of a restoration planting. Elevation was negatively correlated for all ant activity, whilst the age of the planting was positively correlated with ant abundance and species richness. This study shows that ants can be useful monitoring tools in agricultural landscapes, and specifically useful when assessing the effectiveness of on-farm restoration plantings. It also provides a better understanding of the influence of environmental variables on a restoration planting, which in turn can help inform land management decisions.