Dissertations / Theses on the topic 'Eucalypt woodland'

The goal of this work was to quantify the effects of eucalypt woodland blocks on the productivity of native pastures. This research was conducted on the Southern Tablelands of New South Wales. Tree planting or retention is seen by many as an important tool in addressing the problems of soil degradation resulting from clearing and pasture improvement that threaten the sustainability of pasture systems. In particular these are dry land salinity and erosion, both of which affect large areas of agricultural lands in the south east of Australia. Whilst native tree cover remains over substantial portions of Australian pasture lands, mainly on steeper slopes and poorer soils, little has been done to measure the effects of trees on pasture productivity and soil fertility on the Southern Tablelands. Previous studies in other areas have shown a range of effects�from facilitation to inhibition�of pasture growth in the presence of trees. Soil fertility beneath trees has been shown by a number of workers to be elevated in comparison with situations in the open. Given that the range of effects may be highly site dependent, application of results from one area to another may not be valid. Thus it is necessary to measure tree effects on a regional scale if results are to be reliable. Pasture productivity was assessed over a two year period on four sites in the vicinity of Bungendore, New South Wales. A pair of plots was selected on each site, one plot in a block of eucalypt woodland, and the other nearby in an exposed, open situation. Plots were chosen to be as similar to each other as possible with the exception of tree cover. Treed plots had a tree basal area of between 10 and 20 m2 ha-1 and plots had an area of 900 m2. Two of the sites were on granitic soils and had a tree cover consisting predominantly of Eucalyptus pauciflora. The remaining two sites were on soil derived from sedimentary rocks with tree cover consisting mainly of E. mannifera, E. dives and E. melliodora. Perennial native pasture species present were similar across all sites, although their relative contributions to standing biomass varied between sites. As the plots were grazed during the period of measurement, productivity and offtake were measured seasonally using exclosure cages on each plot. Pasture standing biomass was assessed using the comparative yield technique. Microclimate was monitored in each plot by automatic weather stations. Soil moisture to a depth of 45 cm was measured by time domain reflectometry using permanent probes in each plot. Ten additional survey plots on each site, covering the range of tree basal area from 0 - 30 m2 ha-1, were assessed each season in the second year for standing biomass, soil fertility and pasture quality; expressed by nitrogen content and dry matter digestibility. Pasture floristics were measured using the dry-weight-rank method. These additional plots were chosen to be as representative of the paddocks as possible. Over the two years that productivity was measured, it was found to be higher under trees than in the open. This was predominantly due to higher winter and spring growth within treed plots. Grazing offtake was also found to be higher under trees, partly accounting for lower standing biomass found in the treed plots. Wind run, evapotranspiration and photosynthetically active radiation were all reduced by the presence of trees. Beneficial effects of shelter from winds may largely explain the higher productivity observed in the treed plots, and could outweigh negative effects of below ground competition and radiation interception by tree canopies at low to moderate tree densities. Soil moisture was not affected by the presence of trees. Soil fertility also did not differ between treed and open plots nor was there any difference in pasture nitrogen content or dry matter digestibility. On the sites where soils were derived from sedimentary rocks, pasture floristics were found to be related to tree basal area. Themeda ausfralis biomass was negatively related to tree basal area, and was partially replaced by large tussock species such as Poa sieberiana and Chionochloa pallida. A reduction of pasture quality resulted, particularly as the latter species is not grazed to any significant extent. Given the desirability of having deep rooted perennial components in grazing lands, the results of this study indicate that it may be possible to utilise trees to assist in preventing or reducing a range of adverse environmental consequences arising from agricultural activities, without unduly compromising pasture productivity. Additionally, the wide range of environmental conditions provided by a mix of treed and open pasture promotes a higher degree of heterogeneity of the herbaceous layer. This may assist in maintaining productivity over a greater range of climatic conditions than would be the case with a more homogeneous pasture.

In this thesis I present and test a methodology for developing a stand scale index of structural complexity. If properly designed such an index can act as a summary variable for a larger set of stand structural attributes, providing a means of ranking stands in terms of their structural complexity, and by association, their biodiversity and vegetation condition. This type of index can also facilitate the use of alternative policy instruments for biodiversity conservation, such as mitigation banking, auctions and offsets, that rely on a common currency – the index value – that can be compared or traded between sites. My intention was to establish a clear and documentable methodology for developing a stand scale index of structural complexity, and to test this methodology using data from real stands.¶ As a starting point, I reviewed the literature concerning forest and woodland structure and found there was no clear definition of stand structural complexity, or definitive suite of structural attributes for characterising it. To address this issue, I defined stand structural complexity as a combined measure of the number of different structural attributes present in a stand, and the relative abundance of each of these attributes. This was analogous to approaches that have quantified diversity in terms of the abundance and richness of elements. It was also concluded from the review, that stand structural complexity should be viewed as a relative, rather than absolute concept, because the potential levels of different structural attributes are bound within certain limits determined by the inherent characteristics of the site in question, and the biota of the particular community will have evolved to reflect this range of variation. This implied that vegetation communities with naturally simple structures should have the potential to achieve high scores on an index of structural complexity.¶ I proposed the following five-stage methodology for developing an index of stand structural complexity: 1. Establish a comprehensive suite of stand structural attributes as a starting point for developing the index, by reviewing studies in which there is an established relationship between elements of biodiversity and structural attributes. 2. Develop a measurement system for quantifying the different attributes included in the comprehensive suite. 3. Use this measurement system to collect data from a representative set of stands across the range of vegetation condition (highly modified to unmodified) and developmental stages (regrowth to oldgrowth) occurring in the vegetation communities in which the index is intended to operate. 4. Identify a core set of structural attributes from an analysis of these data. 5. Combine the core attributes in a simple additive index, in which attributes are scored relative to their observed levels in each vegetation community.¶ Stage one of this methodology was addressed by reviewing a representative sample of the literature concerning fauna habitat relationships in temperate Australian forests and woodlands. This review identified fifty-five studies in south-east and south-west Australia, in which the presence or abundance of different fauna were significantly (p<0.05) associated with vegetation structural attributes. The majority of these studies concerned bird, arboreal mammal, and ground mammal habitat requirements, with relatively fewer studies addressing the habitat requirements of reptiles, invertebrates, bats or amphibians. Thirty four key structural attributes were identified from these fifty-five studies, by grouping similar attributes, and then representing each group with a single generic attribute. This set, in combination with structural attributes identified in the earlier review, provided the basis for developing an operational set of stand level attributes for the collection of data from study sites.¶ To address stages two and three of the methodology, data were collected from one woodland community –Yellow Box-Red Gum (E. melliodora-E. Blakelyi ) – and two dry sclerophyll forest communities – Broadleaved Peppermint-Brittle Gum (E. dives-E. mannifera ), Scribbly Gum-Red Stringybark (E. rossii E. macrorhyncha ) – in a 15,000 km2 study area in the South eastern Highlands Bioregion of Australia. A representative set of 48 sites was established within this study area, by identifying 24 strata, on the basis of the three vegetation communities, two catchments, two levels of rainfall and two levels of condition, and then locating two sites (replicates) within each stratum. At each site, three plots were systematically established, to provide an unbiased estimate of stand level means for 75 different structural attributes.¶ I applied a three-stage analysis to identify a core set of attributes from these data. The first stage – a preliminary analysis – indicated that the 48 study sites represented a broad range of condition, and that the two dry sclerophyll communities could be treated as a single community, which was structurally distinct from the woodland community. In the second stage of the analysis, thirteen core attributes were dentified using the criteria that a core attribute should:¶ 1. Be either, evenly or approximately normally distributed amongst study sites; 2. Distinguish between woodland and dry sclerophyll communities; 3. Function as a surrogate for other attributes; 4. Be efficient to measure in the field. The core attributes were: Vegetation cover <0.5m Vegetation cover 0.5-6.0m; Perennial species richness; Lifeform richness; Stand basal area of live trees; Quadratic mean diameter of live stems; ln(number of regenerating stems per ha+1); ln(number of hollow bearing trees per ha+1);ln(number of dead trees per ha+1);sqrt(number of live stems per ha >40cm dbh); sqrt(total log length per ha); sqrt(total largelog length per ha); Litter dry weight per ha. This analysis also demonstrated that the thirteen core attributes could be modelled as continuous variables, and that these variables were indicative of the scale at which the different attributes operated.¶ In the third and final stage of the analysis, Principal Components Analysis was used to test for redundancy amongst the core attributes. Although this analysis highlighted six groupings, within which attributes were correlated to some degree, these relationships were not considered sufficiently robust to justify reducing the number of core attributes.¶ The thirteen core attributes were combined in a simple additive index, in which, each attribute accounted for 10 points in a total index value of 130. Attributes were rescaled as a score from 0-10, using equations that modelled attribute score as a function of the raw attribute data. This maintained a high correlation (r > 0.97, p< 0.0001) between attribute scores and the original attribute data. Sensitivity analysis indicated that the index was not sensitive to attribute weightings, and on this basis attributes carried equal weight. In this form my index was straightforward to apply, and approximately normally distributed amongst study sites.¶ I demonstrated the practical application of the index in a user-friendly spreadsheet, designed to allow landowners and managers to assess the condition of their vegetation, and to identify management options. This spreadsheet calculated an index score from field data, and then used this score to rank the site relative to a set of reference sites. This added a regional context to the operation of the index, and is a potentially useful tool for identifying sites of high conservation value, or for identifying sites where management actions have maintained vegetation quality. The spreadsheet also incorporated the option of calculating an index score using a subset of attributes, and provided a measure of the uncertainty associated with this score.¶ I compared the proposed index with five prominent indices used to quantify vegetation condition or habitat value in temperate Australian ecosystems. These were: Newsome and Catling’s (1979) Habitat Complexity Score, Watson et al.’s (2001) Habitat Complexity Score, the Site Condition Score component of the Habitat Hectares Index of Parkes et al. (2003), the Vegetation Condition Score component of the Biodiversity Benefits Index of Oliver and Parkes (2003), and the Vegetation Condition Score component of the BioMetric Assessment Tool of Gibbons et al. (2004). I found that my index differentiated between study sites better than each of these indices. However, resource and time constraints precluded the use of a new and independent data set for this testing, so that the superior performance of my index must be interpreted cautiously.¶ As a group, the five indices I tested contained attributes describing compositional diversity, coarse woody debris, regeneration, large trees and hollow trees – these were attributes that I also identified as core ones. However, unlike these indices, I quantified weeds indirectly through their effect on indigenous plant diversity, I included the contribution of non-indigenous species to vegetation cover and did not apply a discount to this contribution, I limited the direct assessment of regeneration to long-lived overstorey species, I used stand basal area as a surrogate for canopy cover, I quantified litter in terms of biomass (dry weight) rather than cover, and I included the additional attributes of quadratic mean diameter and the number of dead trees.¶ I also concluded that Parkes et al. (2003), Oliver and Parkes (2003), and Gibbons et al. (2004), misapplied the concept of benchmarking, by characterising attributes in terms of a benchmark range or average level. This ignored processes that underpin variation at the stand level, such as the increased development of some attributes at particular successional stages, and the fact that attributes can respond differently to disturbance agents. It also produced indices that were not particularly sensitive to the differences in attribute levels occurring between stands. I suggested that a more appropriate application of benchmarking would be at the overarching level of stand structural complexity, using a metric such as the index developed in this thesis. These benchmarks could reflect observed levels of structural complexity in unmodified natural stands at different successional stages, or thresholds for structural complexity at which a wide range of biota are present, and would define useful goals for guiding on-ground management.

The vegetation of the Sydney Basin, Australia, is highly flammable and subject to a wide range of fire regimes. Sclerophyllous shrubs and sedges are common and in some vegetation types up to 70 % of fuel consumed during a fire can be live. Research into fire behaviour and fuel dynamics has been minimal. To address this issue this thesis investigated the principal factor affecting the ease of ignition and rate of combustion of individual fuel particles and fuel beds in bushfires: dead fine fuel moisture (FFM). Two common Sydney Basin vegetation types, eucalypt woodland and heathland, each with a history of problematic fire management, were measured in the field for diurnal fluctuations in FFM following rain, under conditions similar to when prescribed burns are conducted. The FFM components of current operational fire behaviour models were found to be inadequate for predictions of FFM and fire behaviour under these conditions. The equilibrium moisture content (EMC) of five fuel types from the field site was investigated in a laboratory study. An existing function describing EMC as a function of temperature and relative humidity was evaluated and found to be very accurate for these fuels. Two FFM predictive models incorporating this function were evaluated on the field data and the laboratory results were shown to be applicable to the estimation of FFM in the field. One model gave very accurate predictions of FFM below fibre saturation point, but its accuracy was reduced when screen level conditions were used instead of those measured at fuel level. A recent process-based model that accounts for rainfall showed promise for predicting when fuel is < 25 % FFM. Systematic problems with the radiation budget of this model reduced the accuracy of predictions and further refinement is required. Live fine fuel moisture content (LFMC) of common heathland shrubs and sedge was investigated over two years and found to be both seasonal and influenced by phenology. LFMC minima occurred in late winter and spring (August to October), and maxima were in summer (December to February) when new growth was recorded. The dominant near-surface fuel in mature heath was sedge. It was found to have little seasonal variation in its??? percentage dead but the percentage dead maxima occured at the same time as the LFMC minima of shrubs and sedge in both years. Simple instantaneous models for duff moisture content in woodland and heathland and LFMC and the percentage dead sedge in heathland were developed. The information gained by this study will form the basis for future development of fuel moisture models for prescribed burning guidelines and fire spread models specific to the vegetation communities of the Sydney Basin.

Since the 1990’s Eucalyptus gomphocephala (tuart) has been suffering a significant decline in Yalgorup National Park, approximately 100 km south of Perth Western Australia. Symptoms range from chronic deterioration to sudden mass collapse. The role of Phytophthora pathogens was investigated because the progressive canopy thinning, dieback and heterogeneous distribution of the decline were similar to other forest declines caused by a range of Phytophthora species which are widespread throughout south-west Western Australia and worldwide. In combination with sampling for Phytophthora isolation, an initial diagnostic trial tested the effect of trunk applied phosphite, nutrients and combined phosphite and nutrients on natural stands of declining E. gomphocephala. Phosphite injection was used as a diagnostic tool to identify the possible role of Phytophthora pathogens because the chemical specifically suppresses Phytophthora pathogens and has no known direct fertilizer effect on the host. A range of nutrient treatments was also applied as a diagnostic tool to indicate what nutrient deficiencies may be involved in the decline. Initially no Phytophthora species were isolated from the treatment sites. However, individual and combined injection treatments of phosphite and nutrients improved the crown health over four years with the greatest improvement from treatments of phosphite and zinc sulphide. In combination with further rhizosphere sampling for Phytophthora species, the response of declining trees to phosphite application was further investigated in a second injection trial. Phosphite concentrations from 75 to 375 g phosphite/L improved crown health compared to the control, with the best improvement at 150 g phosphite/L. The positive response of declining trees to phosphite injection implicated a Phytophthora pathogen, despite no Phytophthora species being isolated at this time. Consequently further work was undertaken to determine the involvement of Phytophthora species. Concurrently to both injection trials, several seedling bioassays were conducted. The first bioassay tested the effect of pasteurising soil from a declining site within Yalgorup and healthy sites outside the Yalgorup woodland on E. gomphocephala seedlings grown ex situ. Seedling growth ex situ was not significantly reduced in nonpasteurised soil compared to the pasteurised soils from declining sites, and no Phytophthora species was isolated. To further investigate the disease the fine root and ectomycorrhizal systems of the largest main lateral root of 18 declining E. gomphocephala trees within Yalgorup were exposed using an air spade. Necrotic roots were sampled and the crown, fine root and ectomycorrhizal health were assessed. No Phytophthora species was isolated from necrotic roots; however, crown health of the declining trees was significantly correlated with the fine root and ectomycorrhizae density, suggesting that below ground damage could be involved in the decline. The relationship between the above and below ground health of the air spaded trees was investigated further using an in situ and ex situ seedling bioassay. In the in situ bioassay, seedlings were planted within the exposed root mats of the air spaded trees. In the ex situ bioassay, seedlings were grown within a glasshouse in pasteurised and non-pasteurised soil collected from the air spaded root mats. No Phytophthora species was identified in these bioassays, and seedlings grown ex situ in non-pasteurised soil showed no clear decline symptoms, but the health of the woodland trees was significantly correlated with seedling survival, foliar health and height of the seedlings An additional 32 sites throughout the E. gomphocephala range were sampled for the presence of Phytophthora pathogens using a modified sampling and isolation procedure. From this survey a new Phytophthora species was isolated from five sites from the roots of declining E. gomphocephala, E. marginata and Agonis flexuosa at Yalgorup National Park. Morphologically similar to P. citricola, the new Phytophthora species is unique based on phylogenetic analysis of the ITS and Cox1 gene regions and was named P. multivora. Phytophthora multivora has subsequently been isolated from all experimental sites showing tuart decline. Two experiments tested the pathogenicity of P. multivora to E. gomphocephala and E. marginata. The first experiment examined ex situ the pathogenicity of five P. multivora isolates and one P. cinnamomi isolate on the root systems of E. gomphocephala and one P. multivora isolate on the root system of E. marginata. In the second experiment, the pathogenicity of P. multivora to E. gomphocephala and E. marginata saplings was measured in situ using under-bark stem inoculation. Phytophthora multivora isolates caused significant fine root loss and lesion extension in under-bark inoculated stems of both E. gomphocephala and E. marginata. Phytophthora multivora was also reisolated from necrotic fine roots and lesions of inoculated saplings of both E. gomphocephala and E. marginata, thus satisfying Koch’s postulates. No seedlings died in these pathogenicity trials and P. multivora was not reisolated from beyond the fine roots. There was evidence that P. multivora significantly contributes to E. gomphocephala decline by episodically causing fine root damage leading to chronic deterioration of the trees.

Tall tuart (Eucalyptus gomphocephala) trees are a defining element of the landscape of Perth and the coastal plain to the north and south. However, with the health of some tuart stands deteriorating, most notably at Yalgorup south of Perth, concerns are heightening that the already fragmented tuart ecosystem will continue to contract, leaving a cultural and ecological scar in the landscape. Like many other eucalypt ecosystems, tuart woodlands have had a long association with fire and are believed to have been frequently burnt by the Aborigines prior to European settlement. Today, fragmentation and European land management practices have led to a lower frequency of fire across most remaining woodlands, but also episodes of intense fire at shorter intervals in some areas. Individual fire events as well as fire regimes have the potential to shape the structure, composition and extent of ecosystems, and eucalypt ecosystems are no different. Thus, the impact of fire and fire regimes on tuart health and regeneration was investigated in this study. A survey of the woodlands at Yalgorup revealed tuart decline was present across a range of sites with contrasting fire histories. Tuart health was poorest at the longest unburnt site (35 years) and the site burnt by frequent wildfire (three fires in 13 years), suggesting these extreme fire regimes had played a role in the decline. Nevertheless, low ratings of tree health at sites burnt approximately once per decade, point to factors other than fire playing a role in the decline of tuart at Yalgorup. The tuart populations at Yalgorup were dominated by individuals in larger size-classes and there was a significant negative relationship between tree size and the probability of tree mortality. In one stand in Yalgorup National Park, 38 % of the tuart saplings/trees had died. It follows that the regeneration and development of tuart seedlings into adults will need to occur within the next one to two decades if these woodlands are to persist. Seedling counts confirmed that tuart regeneration was virtually absent in unburnt areas, as is common with eucalypt species. Interpretations of size-class distributions suggested controlled burning contributed little to recruitment, whereas in areas subject to wildfire outside Yalgorup, tuart had regenerated in abundance such that size-class distributions were skewed towards the smaller size-classes. A repeat survey of plots established in 1976 supported anecdotal reports that the mid-storey tree peppermint (Agonis flexuosa) was increasing in density and height in Yalgorup. The skew towards the smallest size-class within peppermint populations at Yalgorup and the presence of seedlings ( > 200 seedlings ha-1) within areas not recently burnt (at least four years since fire) brought into focus the differing mode of regeneration for this species in comparison to tuart. In further contrast to tuart, mature peppermints were in good health with no dead trees reported in the population surveys. A possible role for competition in tuart decline was highlighted by significant negative correlation between peppermint density and tuart health. Together, these results suggest that a general drift from tuart woodland to peppermint forest appears entrenched. Comparative studies of the bark thickness, fire response and resprouting behaviour of tuart and peppermint illustrated the capacity of individuals of both species to persist with recurrent fire. As adults or juveniles, tuart and peppermint resprouted following complete canopy scorch, and often from crown branches: an ability not uncommon for co-occurring tree species and shrubs in this environment. Survival was between 75 and 100 % for fully-scorched tuarts in size-classes ranging from small saplings to trees across six sites. From the small sample of peppermints available for comparison, seedlings and small saplings appeared to be more vulnerable to mortality by fire; only 45 % of individuals with a diameter at breast height ¡Ü 1 cm survived following complete canopy scorch from a controlled burn. With thicker bark, a reliance on stem epicormic buds rather than a lignotuber for resprouting and a greater capacity for height growth, the fire resistance and post-fire recovery of tuart would be expected to differ from that for peppermint. Opportunities for managers to exploit these differences in their burning prescriptions so as to address the drift from tuart to peppermint dominance were outlined. In addition, results indicating a positive response in canopy condition for tuarts with < 10 % canopy scorch following a controlled burn imply that tuart vigour may benefit more immediately from fire. But, observations also revealed that spikes in intensity within controlled burns can damage large unhealthy trees and thereby accelerate the decline process. Thus, the application of fire to declining tuart stands needs to be conducted skillfully. Patterns of growth and survival for tuart and peppermint seedlings were linked to the contrasting ability of the species to establish at burnt and unburnt sites. The purported importance of ashbeds in tuart establishment was demonstrated; at the end of summer (February) at a recently burnt site (Golden Bay), the mean height of tuart seedlings on ashbeds was three times that for those off ashbeds, and the survival rate on and off the ashbeds was 35 % and 15 %, respectively. Therefore, while important, tuart seedlings were not dependent on ashbeds in this instance. The hardy nature of peppermint seedlings when compared to tuart was illustrated when the species were planted in an unburnt area of tuart-peppermint woodland at Yalgorup; nine months after planting, 38 % of the peppermint seedlings survived while only 9 % of the tuart survived. Most of the mortality was linked with the summer-drought period and it was suspected that peppermint seedlings were more drought tolerant. A complementary glasshouse experiment showed that tuart had a greater shoot:root ratio than peppermint, which may be one factor in the greater sensitivity of this species to drought. Further, this experiment revealed that with an increase in nutrient supply, the proportional increment in rooting depth for tuart (1.6 times) was significantly greater than for peppermint (0.3 times). An increased availability of nutrients in ashbeds following fire, particularly for phosphorous, was measured within tuart woodland. Therefore, it was inferred that the availability of nutrients was a critical factor increasing the growth, rooting depth and consequently the greater survival of tuarts on ashbeds. Overall, tuart was concluded to share the Competitor strategy (after Grime) in common with many other eucalypts: rapid growth and the attainment of a large size. On the other hand, peppermint exhibits some of the traits of the Stress Tolerator strategy (after Grime): low minimum resource requirements for growth and survival. The consequence of the increasing cover of peppermint on tuart establishment was explored in field experiments with planted tuart seedlings. No significant impact on seedling growth or survival was observed. There was a declining trend in the seedling growth rates under the high compared to the low peppermint density treatments as the second summer of the experiment was approached, although a statistical difference could not be shown. Peppermint density also had no significant influence on damage to the seedlings from insect attack or the foliar pathogen Mycosphaerella cryptica. Overall, insects and M. cryptica had only an incidental impact on the seedlings: the mean level of canopy damage per affected seedling was < 10 % for either of these two damage agents. Soil type, specifically whether growth occurred on an ashbed was demonstrated to be the most important factor in tuart growth and survival in the 18 months following planting. Although survival was superior on ashbeds (88 %), mean survival was > 50 % in unburnt soil 18 months after planting indicating the potential for restorative plantings to occur in some woodlands between fires. Tuart decline, and the role of altered fire regimes in the decline is complex and further avenues of research were emphasized. Nevertheless, the findings of this and other studies are sufficient to enable purposeful actions to conserve and restore tuart woodlands; recommendations regarding the application of fire with a view to these goals are presented in the final discussion.

The patterns of spatial distribution and abundance were investigated for moth assemblages in the eucalypt woodlands of the Sydney Basin. A total of 228 species of Lepidoptera, distributed among 25 families, were recorded from three national parks located on the perimeter of the Sydney metropolitan region.From within the eucalypt woodland habitat of the Sydney Basin, the study investigated the spatial variation of night-flying Lepidoptera present at several different scales of observation, from the trap level through to across the landscape. Assemblages varied with spatial scale, with uniformity occurring across the landscape as a whole, however becoming patchy at finer spatial scales. Multivariate and turnover analysis indicated that although heterogeneity of abundance and richness may vary significantly depending on spatial scale, sites and national parks contained their own unique suite of species in comparison to one another.The structure of the assemblages of moths in the eucalypt woodlands of the Sydney Basin can vary, and is dependant on the level of spatial scale of observation. Further study needs to be conducted at a range of temporal scales to ascertain the presence of patterns in the Lepidoptera communities in the Sydney region in order to contribute to the development of suitable conservation strategies in the Sydney Basin.

Resumo: O Eucalyptus urophylla destaca-se pelo potencial de utilização de sua madeira, pela sua plasticidade de adaptação a diferentes condições ambientais brasileiras e por ser tolerante ao cancro do eucalipto (Cryphonectria cubensis). A utilização de sementes melhoradas se faz necessária, considerando o iminente déficit florestal que começou no Brasil, a partir de 2004, em função da demanda por madeira ser maior que a sua oferta. Entretanto, o melhoramento dessa espécie, no Brasil, depende da existência de variabilidade genética das populações introduzidas, a qual evita a ocorrência de depressão endogâmica. O presente trabalho visa o estudo genético de uma população base de E. urophylla, originária de Flores e Timor, e instalada em Selvíria-MS. Estudou - se a variabilidade genética dessa população através de análises quantitativas. Dessa forma, os objetivos específicos do estudo foram: a) estimar a variabilidade genética para os principais caracteres silviculturais; b) estimar possíveis ganhos na seleção, utilizando-se da seleção entre e dentro de progênies e do Índice Multi-efeitos, analisando o efeito do desbaste em uma população base de E. urophylla. O experimento foi instalado em 17 de março de 1992, na Fazenda de Ensino, Pesquisa e Extensão da Faculdade de Engenharia, Campus de Ilha Solteira (FE/UNESP), localizada no município de Selvíria - MS. O teste de progênies foi instalado obedecendo a um delineamento experimental em Látice 8x8, quíntuplo, parcialmente balanceado, com 64 progênies provenientes da Estação Experimental do Instituto de Pesquisas e Estudos Florestais (IPEF/ESALQ/USP), localizada no município de Anhembi - S.P. As parcelas contêm oito árvores, no espaçamento de 3,0 x 3,0 metros. Os caracteres quantitativos avaliados e analisados foram: 1- diâmetro à altura do peito (DAP); 2- altura total da planta (H); 3- tipo de ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The Eucalyptus urophylla is detached for its wood potential of utilization for its plasticity of plasticity of adaptation in different Brazilian's environmental conditions and for being tolerant towards the eucalyptus canker (Cryphonectria cubensis). The utilization of improved seeds is needed, considering the imminent woodland's deficit that started in Brazil, in 2004, since the heavy Wood demand was higher than it offers. However the improvements of this specie in Brazil, depends on the existence of genetic variability of the installed populations, which avoids the occurrence of endogamous depression. The present report aims at the genetic study of a base population of E. urophylla, originated from Flores e Timor, and installed in Selvíria-MS. Its genetic variability was studied through quantitative analysis. This way, the specific objectives of this report was: a) Guess the genetic variability for the main silvicultural characters; b) Guess possible earnings in the selection, utilizing this selection among and inside the progenies and inside the progenies and the index of multi-effects, analyzing the skive effect in a base population of E. urophylla. The experiment was installed on March 17th of 1992, on the engineering university's farm of teaching, researches, and extension, campus in Ilha Solteira (FE/UNESP), located in Selvíria - MS. The progenies test was installed obeying an experimental delineation in lattice of 8x8, quintuplet, partially balanced with 64 progenies which came from the experimental station in the woodland's institute of researches and studies, (IPEF/ESALQ/USP), located in of Anhembi - SP. The parcels have 8 trees, in a space of 3,0 x 3,0 meters. The evaluated and analyzed quantitative characters was: 1-Diameter at chest's height (DAP); 2-Total plant's height (H); 3-Kind of bark (CAS); 4- Shape of the shank (FOR); 5- Bifurcation; 6- Survival (SOBR) ... (Complete abstract click electronic access below)
Orientador: Miguel Luiz Menezes Freitas
Coorientador: Mario Luiz Teixeira de Moraes
Banca: Pedro Cesar dos Santos
Banca: Ananda Virgínia de Aguiar
Mestre

The floristic survey and analysis of 100 plots in pure salmon gum woodland in the Great Western Woodlands (GWW) region of Western Australia contributed to the classification of salmon gum communities across south–western Australia. Gradients in annual mean rainfall and temperature, and seasonal rainfall patterns influence the floristic patterns and delineation of five range-wide communities. Strong differences were detected between Wheatbelt and GWW communities, confirming the threatened status of the Wheatbelt salmon gum woodlands.

Grazing by livestock has led to passive clearing of the majority of remaining areas of native vegetation on farmland (remnants) in the Collie river catchment in the south-west of Western Australia. Livestock grazing in these areas removes most of the understorey and prevents recruitment. This thesis documents the impact of livestock grazing on the vegetation dynamics of these remnants through changes to floristics and structure and effects on the soil. It also looks at the possibility of rehabilitation of degraded areas by assessing seed reserves in the soil seedbank and the regeneration of species with the exclusion of grazing. A review of the literature provided a background to this study and looks at the broader issues of the significance of remnants of native vegetation as well as the ecology of disturbance in terms of vegetation response and resilience and deals with the problems of management. Species diversity and richness have decreased with increased grazing intensity and these were negatively correlated with proportion of exotic species. Site ordination of a large sample of remnants placed sites in two major groups based on grazing intensity, with position of sites influenced by proportion of exotic species, proportion of perennial herbs and shrubs and species diversity and richness. Cover and abundance of native perennial species decreased, but increased for exotic annual species with a gradient of response between heavily grazed, lightly grazed and ungrazed sites. Other life form groups such as native annuals, geophytes and native grasses were not significantly affected by grazing. Perennial species that are able to resprout from an underground storage organ as well as germinate readily from seed appear the most resilient to grazing disturbance. Effects of grazing disturbance on the soil included increased surface soil compaction and water repellency as well as significant increases in concentrations of soil nutrients, particularly N and P. Age structure of overstorey species indicated that there has been a lack of recruitment at the heavily grazed sites for some time. Germination of overstorey species took place each year of the study but mortality of seedlings was high, with no seedlings surviving after one summer at the heavily grazed sites. Experiments on the soil seedbank showed a dominance of seed from exotic annual species and a lack of seed from native perennial species within the heavily grazed sites, indicating that natural regeneration is unlikely from this source. Heat treatment of soil samples showed a decrease in germination of exotic species and an increase in the germination of native species. After l to 3 years there was a significant increase in number and cover of native perennial species in exclosure plots, mainly from resprouting. The greatest increase in cover in exclosures was seen for native perennial grasses, while abundance of exotic annuals did not increase significantly compared to adjacent open plots. Time series ordination showed the movement of exclosure plots towards the ungrazed plots after three years, indicating the increase in floristic similarity between the exclosures and the ungrazed plots. This study has shown that grazing has resulted in a shift from a community dominated by native perennial species to one dominated by exotic annual species. High grazing intensity and short grazing history, climatic variability and effects on the soil are the major factors affecting the observed ·responses of the vegetation to grazing. Natural regeneration in degraded remnants is possible if livestock are excluded. Rehabilitation of some sites is also required and a procedure is suggested.

Made available in DSpace on 2014-06-11T19:29:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-31Bitstream added on 2014-06-13T18:39:35Z : No. of bitstreams: 1 souza_cs_me_ilha.pdf: 372222 bytes, checksum: a23d8dffc9394536874e4aba2dd0153a (MD5)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
O Eucalyptus urophylla destaca-se pelo potencial de utilização de sua madeira, pela sua plasticidade de adaptação a diferentes condições ambientais brasileiras e por ser tolerante ao cancro do eucalipto (Cryphonectria cubensis). A utilização de sementes melhoradas se faz necessária, considerando o iminente déficit florestal que começou no Brasil, a partir de 2004, em função da demanda por madeira ser maior que a sua oferta. Entretanto, o melhoramento dessa espécie, no Brasil, depende da existência de variabilidade genética das populações introduzidas, a qual evita a ocorrência de depressão endogâmica. O presente trabalho visa o estudo genético de uma população base de E. urophylla, originária de Flores e Timor, e instalada em Selvíria-MS. Estudou - se a variabilidade genética dessa população através de análises quantitativas. Dessa forma, os objetivos específicos do estudo foram: a) estimar a variabilidade genética para os principais caracteres silviculturais; b) estimar possíveis ganhos na seleção, utilizando-se da seleção entre e dentro de progênies e do Índice Multi-efeitos, analisando o efeito do desbaste em uma população base de E. urophylla. O experimento foi instalado em 17 de março de 1992, na Fazenda de Ensino, Pesquisa e Extensão da Faculdade de Engenharia, Campus de Ilha Solteira (FE/UNESP), localizada no município de Selvíria – MS. O teste de progênies foi instalado obedecendo a um delineamento experimental em Látice 8x8, quíntuplo, parcialmente balanceado, com 64 progênies provenientes da Estação Experimental do Instituto de Pesquisas e Estudos Florestais (IPEF/ESALQ/USP), localizada no município de Anhembi – S.P. As parcelas contêm oito árvores, no espaçamento de 3,0 x 3,0 metros. Os caracteres quantitativos avaliados e analisados foram: 1- diâmetro à altura do peito (DAP); 2- altura total da planta (H); 3- tipo de...
The Eucalyptus urophylla is detached for its wood potential of utilization for its plasticity of plasticity of adaptation in different Brazilian’s environmental conditions and for being tolerant towards the eucalyptus canker (Cryphonectria cubensis). The utilization of improved seeds is needed, considering the imminent woodland’s deficit that started in Brazil, in 2004, since the heavy Wood demand was higher than it offers. However the improvements of this specie in Brazil, depends on the existence of genetic variability of the installed populations, which avoids the occurrence of endogamous depression. The present report aims at the genetic study of a base population of E. urophylla, originated from Flores e Timor, and installed in Selvíria-MS. Its genetic variability was studied through quantitative analysis. This way, the specific objectives of this report was: a) Guess the genetic variability for the main silvicultural characters; b) Guess possible earnings in the selection, utilizing this selection among and inside the progenies and inside the progenies and the index of multi-effects, analyzing the skive effect in a base population of E. urophylla. The experiment was installed on March 17th of 1992, on the engineering university’s farm of teaching, researches, and extension, campus in Ilha Solteira (FE/UNESP), located in Selvíria - MS. The progenies test was installed obeying an experimental delineation in lattice of 8x8, quintuplet, partially balanced with 64 progenies which came from the experimental station in the woodland’s institute of researches and studies, (IPEF/ESALQ/USP), located in of Anhembi - SP. The parcels have 8 trees, in a space of 3,0 x 3,0 meters. The evaluated and analyzed quantitative characters was: 1-Diameter at chest’s height (DAP); 2-Total plant’s height (H); 3-Kind of bark (CAS); 4- Shape of the shank (FOR); 5- Bifurcation; 6- Survival (SOBR) ... (Complete abstract click electronic access below)

This thesis examines the effects of species, rainfall and soil type on tree biomass regressions, as well as the effects of stand dominance and structure on stand biomass regressions in north-east Australian woodlands. This was achieved by examining tree characteristics and biomass relationships for a series of woodland monitoring sites throughout the study area. This study utilised a modified data set from this permanent monitoring site network to provide structural attributes for trees and communities of varying composition in the grazed woodlands. These data were supplemented with environmental data and tree harvest data sets. Initially, the research reported in this thesis developed allometric and stand biomass regressions for Callitris glaucophylla communities. This research also demonstrated that changes in tree-form were not reflected in changes in the environment, nor did such changes reflect changes in tree biomass regressions for three eucalypt species. As a result, a common regression provides a robust estimate of total aboveground biomass of eucalypt trees in the study area. Thus expensive destructive harvesting can generally be avoided for minor eucalypt species. Finally, this study demonstrated a successful methodology that described the stand structure of all the grazed woodland sites based on tree heights. This methodology was developed to allow the expansion of a single stand regression to estimate stand biomass across the entire north-east Australian woodlands. The findings demonstrated in this study, combined with the long-term data from the permanent monitoring network sites, should enhance the estimation of carbon flux within eucalypt communities of north-east Australia’s grazed woodlands.

Forest ecosystems contribute substantially to biogeochemical processes on the earth. Understanding their responses to climate change is essential to the prediction of future climate as they could accelerate or decelerate the rates at which atmospheric CO2 concentrations and associated global temperatures are rising, depending on their carbon (C) storage capacity. However, very little is known about how mature forests respond to climate change, particularly those growing under P limitation, or NP co-limitation. This thesis aimed to investigate the effects of elevated (e)CO2 (ambient +150 ppm) on soil nutrient dynamics and understorey plant community composition in a novel field CO2 exposure experiment in a mature, P-limited, native Eucalyptus woodland (EucFACE). It also investigated the effects of elevated temperature (eTemp; ambient +3 °C) on soil nutrient dynamics using whole-tree chambers (WTCs) in which Eucalyptus tereticornis trees were grown. I found seasonally-dependent positive effects of eCO2 on the availability and turnover of soil N and P over an 18-month period, with concurrent higher concentrations of dissolved organic carbon (DOC) in soil solution and lower soil pH. P availability was enhanced to a greater extent than N, resulting in decreased N:P ratios. The WTC experiment showed that, whilst eTemp enhanced P turnover and availability, and increased DOC in soil solution, effects on N availability and turnover were not statistically significant. In the case of both eCO2 and eTemp, increased DOC alongside increased soil P availability and decreased soil N:P ratios, suggests that plants adjusted their C investment strategies as their demand for nutrients, particularly P, increased. The EucFACE experiment also showed that eCO2 increased C3 plant species abundance compared to C4, and decreased species diversity in the understorey community. This thesis provides novel insights into and empirical evidence of soil nutrient, particularly P, dynamics under P-limited ecosystems in a higher CO2 and warmer world.

The Rufous Treecreeper (Climacteris rufa), Yellow-plumed honeyeater (Lichenostomus ornatus) and the Western Yellow Robin (Eopsaltria griseogularis) are focal species and were investigated to assess the impacts of climate change and severe habitat fragmentation on the genetics and viability of remaining populations. This study was located within the west Australian wheatbelt where 93% of the native vegetation, including 97% of the York gum, wandoo and salmon gum woodlands have been cleared for agriculture (Saunders, et al., 1989) and where climate modelling predicts hotter and dryer weather conditions (CSIRO, 2005, IOCI, 2002). The Dryandra woodlands contains the largest native vegetation remnants in the central wheatbelt with a combined area of 28 066 ha and provides habitat for a diverse assemblage of flora and fauna many of which are in Decline, Threatened or Specially Protected (NWC, 1991). The effects of habitat loss and fragmentation on the gene flow and population structure on the Rufous Treecreeper, was assessed within the Dryandra woodlands and across a range of fragmented habitat spanning approximately 100 km. Microsatellite and mitochondrial DNA data was applied to a spatial genetic and phylogeographic analysis. AMOVA shows genetic variation to be higher within populations (78%) than among populations (22%) and populations did not conform to Hardy Weinberg Equilibrium. This infers gene flow exceeds genetic drift across the region and the presence of migration between remnant habitats. Isolation by Distance was not found within Dryandra or across the region and infers the effective dispersal distance of the Rufous Treecreeper exceeds the geographical distance of sampling sites. However a Mantel’s Test found a correlation (r=0.316, p=0.004) with a distance of 28kms, within the Dryandra woodlands. A Spatial Autocorrelation of microsatellite DNA found a genetic structure of up to approximately 25kms (V=0.55) and beyond the Dryandra woodlands, shows genetic discontinuities where dispersal is more likely to occur. Landscape interpolation of genetic distance shows high genetic differentiation within the Dryandra woodlands and decreasing in an easterly direction where habitat size decreases and the distance between habitat increases. The Maximum Difference Delaunay Triangulation shows population boundaries of 12 populations within the woodlands including 3 central populations that are 1.3 km apart. A Bayesian Computation of microsatellites found a Continent-Island pattern of population structure across a distance of 85 km. Ritland’s Kinship Coefficient found dispersal patterns amongst populations within the Dryandra woodlands and a genetic neighbourhood size of about 1.7 km. Loiselle’s Kinship Coefficient found a unidirectional pattern of migration from the woodlands to smaller, isolated habitats with a maximum dispersal distance of 48 km. A Landscape Interpolation of male and female Rufous Treecreepers show a female bias in dispersal from Dryandra, with higher genetic divergence patterns in isolated remnants where habitat and nesting hollows are limiting. Rufous Treecreeper mitochondrial DNA (partial cytochrome b gene) data was applied to the Mantel’s Test and found no correlation in Dryandra or the surrounding area but did show a positive correlation at a distance of 500kms and infers at least 2 different bioregions within this distance for this species. Results from the Interpolation and Principal Component Analysis show genetic variation decreasing with increasing distance from Dryandra in an easterly and southerly direction. The highest divergence patterns were found in Dryandra, North Yilliminning, Wickepin and Commondine Reserve. Genetic patterns with high similarity were found in Dongolocking and Highbury sites south- east of Dryandra and are most likely remnant populations that once belonged to a larger, continuous population or gene pool. A geographical distribution of shared mitochondrial haplotypes found a historical range prior to land clearing of approximately 85kms. A genealogy study based on coalescence found the earliest ancestral haplotypes belonged to Dryandra, North Yilliminning and Wickepin populations and should be prioritised for long term conservation purposes. Also, novel sequences of partial cytochrome b gene for the Yellow-plumed Honeyeater and Control Region for the Western Yellow Robin was resolved for further research. The ecological niche and distribution of the Rufous Treecreeper was assessed using a distance based Redundancy Analysis (db-RDA) and a Habitat Suitability study. The db-RA found slope and aspect explained 29.16% (p= 0.04) of the genetic variation (phi) of mitochondrial DNA, which infers a relationship between landscape features and historical divergence patterns. Since old growth Eucalyptus wandoo trees are a critical habitat requirement for nesting hollows (Rose, 1993) a georeferenced (GIS) habitat suitability map was constructed from a vegetation survey (Coates, 1995) to show the distribution of E.wandoo and Rufous Treecreepers within Dryandra. Also using demographic information of the Rufous Treecreeper from a previous study (Luck, 2001) and RAMAS GIS (Akcakaya, 2002), it was estimated that the Dryandra contained enough suitable habitat for a maximum of 158 populations or 1 106 individuals. The impact of climate change on the Dryandra woodlands and the Rufous Treecreeper was measured by annual rainfall measurements (BOM, 2011), satellite imagery of tree foliage cover of each sampling site and mist net capture recapture data. This study found a declining trend in rainfall patterns and in 2010, the annual rainfall (277.4mm) fell below the minimum climatic range (350mm) of E.wandoo forests. Based on climate modelling (CSIRO, 2005) the predicted reduction rainfall will eventually will negatively impact these forests by inducing a permanent state of drought. A critical threshold of 7.73% foliage cover was found, where foliage cover does not appear to recover foliage cover beyond 11.53% after a reduction to 7.73% in 2003. This indicates a critical threshold of percentage tree canopy cover for the E. wandoo in Dryandra. A linear regression found a significant relationship (p = 0.036) between previous year’s rainfall and percentage foliage cover. This delayed response to rainfall is explained by the defence mechanisms of E.wandoo that provide this species with drought tolerance (Veneklaas & Manning, 2007). A logistic regression (GLM) found foliage cover within the same year to be a significant predictor (p = 0.039) of Rufous Treecreeper captures. Therefore declining rainfall patterns and tree canopy cover have a direct impact on the abundance of Rufous Treecreepers. The apparent survival rate estimate for the Rufous Treecreeper was 0.65 (SE 0.13) and 0.303 (SE 0.08) for the Yellow-plumed Honeyeater. Alternate modelling is required for the Yellow-plumed honeyeaters to account for their varied seasonal dispersal patterns and the Western Yellow Robin data could not be used for this demographic study because of small sample size. During 1997 and 1999 adult survival rates for Rufous Treecreepers within Dryandra was 0.76 (Luck (2001) and show the Rufous Treecreepers within the Dryandra woodlands are continuing to decline. A comparison of the two survival rates shows there is a reduction of 0.11 within an 8 year period (a single generation), which coincided with a 5.16% decrease in mean foliage cover during sampling times. This study concludes that climate change is negatively impacting E.wandoo forests and that tree foliage cover is not only a significant predictor in determining the presence of Rufous Treecreepers within the Dryandra woodlands, but also effects the short term survival and long term viability of this focal species.

Armillaria luteobubalina Watling & Kile is a common and destructive primary pathogen in a number of plant species. The pathogen is widely distributed in the wet sclerophyll forest, dry sclerophyll forest and woodland, and the coastal dune system in south-western Australia. The current study was conducted to _determine the nuclear behaviour during the life cycle and the spatial distribution of genotypes within disease centres. Basidiomes were collected from two disease centres: one in the coastal dune system; and the other from the Eucalyptus wandoo Blakey woodland. Monosporous isolates, putative diploid isolates and gill tissue were obtained from the basidiomes. Overall, 71 and 173 monosporous and diploid isolates, respectively, across the two sites. A preliminary study with streptomycin and lactic acid to enhance the recovery of non-contaminated basidiospores was conducted. In order to determine the ploidy and nuclear arrangement during different stages of the life cycle, the isolates and gill tissue were stained with orecein, 4', 6-diaminodino-phenylindol, phloxine or trypan blue. Additionally, mycelial interactions were utilised to describe the spatial distribution of genotypes at both disease centres by pairing haploid-haploid, diploid haploid and diploid-diploid. Additionally, the identity of the collected basidiomes were confirmed by interspecific pairings of vegetative isolates. The results of this investigation clearly demonstrate that the addition of streptomycin had no adverse effects on basidiospore gennination and was used successfully to isolate monosporous isolates. Additionally, 4°C was the optimum temperature for the long-term storage of viable spores. A. luteobubalina was shown to be amphithallic and to produce binucleate (8.45 %) and uninucleate (91.55 %) basidiospores. The results provide evidence that the variation in the nwnber of sterigmata between basidia is responsible for the incorporation of two nuclei within the basidiospores. The heterothallic life cycle of A luteobubalina begins with the germination of a haploid basidiospore to produce a haploid mycelium. The mating of two compatible monokaryotic isolates produce a vegetative diploid. The vegetative diploid persists until it undergoes a somatic nuclear reduction within the subhymenium, prior to basidium formation and subsequent basidiospore production. The mating interactions demonstrated that the Trigg disease centre is dominated by one diploid genotype, compared to 2 diploid genotypes at the Pykes road disease site. During the intraspecific pairing of monokaryotic and diploid isolates, 5 A and 6 B alleles were identified. The study demonstrates for the first time: the vegetative diploid stage in the secondary mycelia; a somatic haploidisation occurs within the basidia; and the pseudohomothallic behaviour of A. luteobubalina.

Clearance of Eucalyptus woodlands has resulted in soil deterioration and lost agricultural production, due to wind erosion, salinity and soil acidity. Despite increasing efforts to reverse these trends through Landcare and other revegetation and agroforestry programs, there is a lack of experimentally-based information about the effects of trees on native pasture performance. The study was carried out in a temperate environment (Southern Tablelands, New South Wales). The altitude at the study sites ranged from 740 to 880m and the aspect at the experimental plots varied from SE to SW. The nearest site was 16 km from Canberra Airport and all sites were situated within similar rainfall isohyets as Canberra Airport. Thus climatic conditions were expected to be similar. Climate records at Canberra Airport indicate that January is the hottest month with mean maximum temperature of 27.7 �C and July is the coldest month with a maximum of 11.1 �C. Rainfall in the area ranges from 37.5 to 66.0 mm monthly average in June and October respectively. The main tree species in the study area were Eucalyptus pauciflora, E. melliodora and E. mannifera. Furthermore, Poa labillardieri, P. sieberiana, Themeda australis, Danthonia penicillata and Microlaena stipoides were the most abundant pasture species on the experimental plots. Species of clover (Trifolium spp.) were also abundant among the herbs. This study used pasture assessment techniques to quantify the effects of remnant patches of Eucalyptus open woodlands on the composition, quality and biomass production of herbaceous understorey vegetation. Microclimate and soil nutrients were also compared under trees and in the open. In addition, consumption by vertebrate grazers under Eucalyptus trees and in the open was compared. Tree density and basal area were compared with herbage standing crop. Remnant patches of Eucalyptus open woodlands modify the microclimate by reducing wind reaching the understorey vegetation. However no significant effects on ambient air temperature and relative humidity were recorded. The effect of trees on soil moisture was contingent to differences between the four sites and soil depth. Despite a 13% higher soil organic matter in the top 15 cm of soil under trees, soil total nitrogen and total phosphorus did not differ from that in the open. Surface soil pH values were lower (by 0.2 units) under the trees. No significant effect of trees on pasture species richness was found. However the classification of quadrats on the basis of species presence showed a distinction between species composition under trees and in the open at one of the four sites. vi The contribution of pasture species to total dry weight on plots under trees and in the open did depend on the particular species involved and was also contingent to differences between sites. However at the sites where Vulpia bromoides and Poa sieberiana were abundant, the two species dominated the biomass under trees. Whereas Microlaena stipoides var. stipoides dominated the biomass under trees at two sites and in the open at only one of the four sites. Pasture total N content differed between sites. Two of the sites had significantly higher (5.9% and 19.7%) N content under trees. On the contrary, pastures at one site contained 18.7% higher N content in the open. The total P content was 18% higher in pastures under trees. Overall, the pasture standing crop under trees was 15% less than in the open during August to May. Vertebrate grazers consumed about the same amount of pasture under the trees and in the open at the four experimental sites.

Species reintroductions have become an increasingly prevalent conservation tool to combat species decline and extinction. Reintroduction programs aspire to re-establish a self-sustaining population of a species in an area where the species was formally extant. This thesis contributes to conserving a threatened species, the Brown Treecreeper (Climacteris picumnus), through an experimental reintroduction, and also informs the effectiveness of restoration treatments in the nature reserves where reintroduction occurred. I first reviewed Australian species relocations published within peer-reviewed literature. I identified key areas where improvements to relocation programs can be implemented, including: (1) integrating an experimental framework; (2) strategic, long-term monitoring; and (3) criteria for success. These findings contributed to ensuring that the Brown Treecreeper reintroduction was conducted to a high standard. Seven Brown Treecreeper social groups (43 individuals) were reintroduced into Mulligans Flat and Goorooyarroo Nature Reserves in the Australian Capital Territory in south-eastern Australia in November 2009. The reserves are the location of a large-scale experimental restoration project. Restoration treatments include the addition of coarse woody debris, maintenance of variation in ground vegetation cover, and the installation of nest boxes. At release, 18 Brown Treecreepers were fitted with radio-transmitters to assist daily monitoring until February 2010. Survival of individuals one year post-release (15% confirmed adult survival) failed to meet the pre-determined criteria for success (40% adult survival). Therefore, the reintroduction program cannot be deemed as successful. I examined the influence of experimental restoration treatments on Brown Treecreeper movement, habitat use and behaviour. This enabled assessment of restoration effectiveness and the suitability of using existing ecological knowledge to inform reintroduction outcomes and post-release behaviour. Brown Treecreeper movement characteristics were not influenced by habitat quality. Social groups showed a preference for settling in areas with low levels of ground vegetation cover, which improves ground foraging efficiency. However, the overall influence of habitat quality on settlement was less than predicted. The addition of coarse woody debris benefited the species by increasing the probability of foraging on the ground or on logs. The amount of ground foraging by reintroduced Brown Treecreepers was less than has been observed in other populations. This highlights the requirement for further ground layer management including promoting cryptogamic crust development, improving leaf litter levels, and controlling grazing by native herbivores. I analysed the influences on the apparently high predation rate of Brown Treecreepers. There were fewer refuges in the reintroduction reserves compared to areas where birds were sourced, indicating a reduced ability to escape from predators. The reintroduction reserves also had lower quality ground foraging habitat quality. However, reintroduced individuals dispersed extensively and settled in higher quality habitat more closely resembling the source site. Results from this thesis provide crucial information regarding restoration effectiveness and Brown Treecreeper ecology. Whilst some restoration treatments were successful, there was insufficient improvement to support the species. Complete woodland restoration may require incorporation of finer details and more spatial variation and innovative methods than ordinarily considered. Unexpected results from this study also reinforce the importance of integrating an experimental framework to inform reintroduction biology.

University of Technology, Sydney. Faculty of Science.
Biological invasions pose one of the greatest threats to global biodiversity and frequently result in the widespread loss of flora and fauna. Biological invasions have become a major focus of ecology in recent decades, and in particular, the invasive species radiata pine (Pinus radiata D. Don) is of considerable concern. Radiata pine has a very limited distribution in the northern hemisphere in its natural range. Its utility in the timber and manufacturing industries, however, has lead to widespread planting, especially in the southern hemisphere, where over 4 million hectares of plantations have been established. In fact, radiata pine is now the most commonly cultivated conifer in the world. A growing body of evidence from studies in the southern hemisphere has shown that pines are spreading invasively beyond the confines of plantations, displacing native species and becoming the dominant species in a number of vegetation types. The negative ecological impacts associated with pine plantations now extend well beyond plantation boundaries. While a number of studies have examined the invasion of individual pines (wildings) from plantations into surrounding vegetation, very few studies have considered the impacts of pine plantations and pine litter on surrounding native plant communities. Pine litter is defined here as structures shed from pines; primarily needles and pollen cones, but also seeds and twigs. In New South Wales (Australia), pine plantations are frequently bordered by native vegetation, providing ideal conditions for pine-litter intrusion to occur. Nevertheless, rates of pine-litter intrusion have never been quantified. Furthermore, the responses of an ecosystem to an influx of pine litter are largely unknown. The aims of this thesis are first to quantify the intrusion of pine litter into native vegetation adjacent to pine plantations and second to determine the impacts of pine litter intrusion on the structure and function of native woodland communities. Fieldwork was conducted at two geographically disparate locations in the Central Tablelands of New South Wales (Australia): Jenolan Caves Karst Conservation Reserve and Gurnang State Forest. At both sites, pine plantations and native woodland are separated by a narrow fire trail that is only a few metres wide. A comparative framework is used, whereby sites in eucalypt woodland that were adjacent to pine plantations (adjacent sites) were compared with sites in eucalypt woodland that were not adjacent to plantations but rather adjacent to eucalypt woodland (reference sites). As the effect of plantations is expected to decrease with increasing distance into native vegetation, sampling plots located at distances of 0, 5, 15, 25 and 50 m from the edge of the native vegetation were established at reference and adjacent sites. This enabled testing of both the impact of plantations on native vegetation, and also the spatial extent of this impact on native vegetation. The first and crucial step in examining the intrusive effects of pine plantations was to quantify the amount of native and exotic litterfall at reference and adjacent sites. At each sampling plot, I measured the amount of native and exotic litterfall (i.e. pine litter intrusion) every 4 weeks for 1 year at Gurnang State Forest and for 2 years at Jenolan Caves Karst Conservation Reserve. Pine needles and pollen cones were found to be a significant component of litterfall in woodlands adjacent to pine plantations. Exotic and native litterfall varied both seasonally and annually. Interestingly, peak needlefall from pines occurred in autumn and winter, which coincided with the minimum native leaffall. Conversely, pine needlefall was at a minimum during summer, during which native leaffall was high. The comparison of two separate woodlands adjacent to plantations revealed similar patterns of pine-litter intrusion although the absolute quantity of pine-litter intrusion was greater at Jenolan compared to Gurnang. Comparison of the carbon (C) and nitrogen (N) content of litterfall revealed subtle yet significant differences between pine and native litterfall. Pine litter generally had a lower N content than native leaffall at Jenolan, but a higher N content than native litter at Gurnang. At both locations, the pine litterfall is additional to native litterfall and as such, pine-litter intrusion is adding additional resources to woodlands adjacent to the plantation. Having determined the rates of pine-litter intrusion, the next step was to determine the fate of pine litter once it had intruded into woodland vegetation. In the absence of fire, plant litter is ultimately broken down through the decomposition process. A three-by-three experimental design was employed, where 3 litter types (pine, native and a 50:50 mix of pine and native litter) were placed under 3 different conditions (‘reference sites’, ‘adjacent sites’, and sites within pine plantations). Litterbags were constructed and filled with a known mass of litter before being placed in the field. Every 8 weeks, for 18 months, litterbags were collected and destructively sampled. Decomposition was measured as a function of weight loss through time, while the corresponding nitrogen and carbon contents were determined. While decomposition was quite slow overall, rates of decomposition were generally faster for native litter than for pine litter. Throughout the experiment, the N concentration of litter increased in all litter types although it was higher in native litter than in pine litter. An important consequence of the slower rate of decomposition of pine litter is likely to be the accumulation of pine litter in woodlands adjacent to plantations. This may have severe implications for the structure and composition of plant communities adjacent to plantations. To test this, I examined the seasonal and spatial patterns of plant community structure of eucalypt woodlands surrounding pine plantations at Jenolan and Gurnang. Eucalypt woodland at Gurnang showed only a minor change in the structure and composition of understorey vegetation at sites nearest the plantation. In contrast, eucalypt woodland at Jenolan showed a much stronger response to plantations, with significantly lower total species richness at adjacent sites compared with reference sites. This resulted in a pronounced ‘edge effect’ up to 15 m into eucalypt woodland adjacent to pine plantations. Canonical correspondence analysis was used to examine the relationship between environmental variables and plant community structure. Pine litterfall explained a significant portion of the variation in plant community structure at reference and adjacent sites at Jenolan, where large quantities of pine litter intrude into native vegetation. At Gurnang, where smaller quantities of pine litter intrude into eucalypt woodland, pine litter intrusion explained a lower portion of the variance between reference and adjacent sites. The plantation at Jenolan consists of large, mature pines that have formed a dense closed canopy, while at Gurnang, the plantation has been established more recently and the pines are not as large, and have not formed a closed canopy. The plantations at Jenolan are therefore a greater source of litter and are also likely to have more pronounced influence on the microclimate compared with the plantations at Gurnang. Lower diversity of flora at Gurnang also may limit the ability to detect differences in plant communities between reference and adjacent sites. Finally, I investigated the impact of pine litter on plant community structure by testing the hypothesis that pine litter facilitates the germination and growth of radiata pine seeds. Using a manipulative glasshouse experiment, radiata pine seeds were sown in pots and exposed to varying quantities of different litter treatments (pine litter, native litter and a 50-50 mix of pine and native litter). The germination and subsequent growth and survival of pines were measured over a period of 2 months. Litter depth but not litter type was found to be an important determinant of pine seedling establishment. With the exception of treatments that were covered by a small layer of litter (i.e. 1 cm) increases in litter depth resulted in delayed and lower rates of seedling emergence. Although pine and native leaves are different shapes (i.e. needle vs. broadleaf) and form very differently structured litter layers (dense mat vs. loosely structured), both litters appear to cause similar physical resistance to seedling establishment. These results indicate that litter accumulation resulting from pine intrusion can alter the establishment of pine seedlings. Given the invasive nature of radiata pine, it is highly likely that increased litter depth resulting from pine-litter intrusion will influence the establishment of many native species. In summary, significant quantities of pine litter were found to intrude into native woodland adjacent to pine plantations, which in turn, appears to be responsible for observed shifts in ecosystem structure and function. This is of particular concern in instances where pine plantations are situated adjacent to native vegetation that has been set aside specifically for conservation purposes. I therefore suggest the provision of a buffer zone around plantations in order to minimise intrusive impacts of plantations on native biodiversity. Whilst this can be achieved using a number of techniques, careful consideration of the structure of native vegetation is needed when selecting the appropriate technique. Having an inappropriate buffer may have an undesirable influence on native vegetation.

In this thesis I present and test a methodology for developing a stand scale index of structural complexity. If properly designed such an index can act as a summary variable for a larger set of stand structural attributes, providing a means of ranking stands in terms of their structural complexity, and by association, their biodiversity and vegetation condition. This type of index can also facilitate the use of alternative policy instruments for biodiversity conservation, such as mitigation banking, auctions and offsets, that rely on a common currency – the index value – that can be compared or traded between sites. My intention was to establish a clear and documentable methodology for developing a stand scale index of structural complexity, and to test this methodology using data from real stands.¶ ...

Revegetation is a key conservation activity in areas that have been extensively cleared and is undertaken in the hope it will prevent further species losses, mitigate land degradation and return functional ecosystems to degraded areas. Although revegetation has the potential to achieve these outcomes, the field is still relatively young and actively developing in terms of standards and best practice. As a result, the long-term viability, functionality and resilience of many re-planted systems remains uncertain. There have been calls for revegetation to move towards more ecologically informed designs and one way to achieve this is for plantings to mimic the composition and structure of natural vegetation. However, the outcomes of failing to undertake such practice is still poorly understood. The spatial arrangements of plants are central to natural communities and influence the majority of ecological processes that occur. Consequently, the position of plants within revegetated sites may affect the long-term viability and resilience of these restored systems. Despite this, planting arrangements are rarely considered an important feature of revegetated communities, especially for variables other than overall planting density and this may limit the ecological value of revegetated communities. The primary aim of this thesis was to examine how planting arrangements influence the ecological processes occurring within revegetated sites, with a focus on reproduction in woodland systems. I first review the available literature and synthesise information from natural ecosystems, plantation communities, and experimental plantings to identify ways plant arrangements may influence the ecological function of revegetated systems and highlight key knowledge gaps. The data chapters of my thesis then evaluate how planting arrangement influences pollination, seed production, plant mating patterns and patterns of gene flow in a revegetated eucalypt woodland in southern Australia. Following this, I document the arrangement of plants within remnant eucalypt woodlands and identify key features that can potentially be incorporated into revegetation design if projects seek to re-create more natural woodland plant arrangements. I found that plant arrangements have the potential to influence a range of ecological processes, from those at the individual plant level (survival, growth), the population and community level (pollination, seed dispersal) and the ecosystem level more generally (habitat provision, erosion). My experimental results support these expectations and although plant reproduction was highly variable, the spacing between conspecifics and the degree of aggregation influenced seed production and plant mating patterns in the Eucalyptus species studied, whereas population abundance had little influence. Taken together, these findings suggest that woodland revegetation should consider not only the number of each species to be planted, but also the fine-scale arrangement (conspecific spacing, aggregation) of those species, if reproductively productive populations are to be established. One way to achieve this is to re-create more natural plant arrangements, where aggregation is common and large distances between conspecifics are rare. The challenge is now to find ways to effectively incorporate spatially designed revegetation into the planning and planting phases of revegetation and then monitor the outcomes of this approach.
Thesis (Ph.D.) -- University of Adelaide, School of Biological Sciences, 2018

Approximately a third of the Earth’s surface is degraded. The enormous scale of degradation has stimulated multilateral agreements with ambitious restoration targets (e.g. The Bonn Challenge aspires to restore 350 million ha by 2030). Humankind has greater awareness than ever before of the factors contributing to landscape degradation, and has developed sophisticated practices to assist in its repair. The principal management intervention used to combat the biodiversity declines associated with land degradation is restoration. However, unprecedented environmental challenges from climate change, rapid biodiversity loss, and human population pressures add to the complexity of achieving sustainable restoration outcomes. There are valid concerns that sub-optimal restoration interventions are jeopardizing outcomes, which brings into question our capacity to reach global targets. To establish a strategic approach for improving restoration practice and to promote resilient outcomes, I reviewed current restoration practices and found that the management of plant genetic resources and inconsistent monitoring of projects are key impediments to optimal restoration outcomes. I found a suitable mechanism for investigating these knowledge gaps, through embedded experiments, and subsequently established them in restoration projects. I addressed the plant genetic resource knowledge gaps by testing in situ the relationship between plant fitness and seed origin for six Myrtaceae species. I investigated plant fitness in three empirical studies that included five common garden experiments, from provenances spanning 2.5 degrees of latitude (ca. 460 km) in southern Australian eucalypt woodlands, and found sub-optimal plant performance was common. Furthermore, signals of maladaptation occurred in two of my three empirical studies. I determined that the Myrtaceae species I studied persisted in a range of climatic conditions by combining specific adaptations to aridity and acclimating to new environmental conditions via phenotypic plasticity. I confirmed that this response was strongly directional (e.g. arid to mesic), and the genetic diversity harboured in non-local provenances could be harnessed to counteract plant fitness concerns (e.g. adaptation lags due to climate or lack of connectivity due habitat fragmentation), and ultimately help to achieve more sustainable outcomes. I then explored the utility of high throughput 16S amplicon sequencing (e.g. metabarcoding soil eDNA) as an assessment tool to assist in monitoring restoration performance. I used metabarcoding of soil eDNA to assess a chronosequence of restoration and found that the process of restoration (i.e. revegetation of the native plant community) strongly impacted soil bacteria, an important functional component of the ecosystem. I observed dramatic changes of the bacterial community after eight years of revegetation, where the bacterial communities in younger sites were more similar to cleared degraded land and older restoration sites were more similar to remnant native stands. This work has identified evidence of community flux and functional recovery following restoration that would remain unrecognised through orthodox monitoring. The synthesis of this work supports the use of evidence-based approaches to iteratively improve restoration practices. Science-practice synergies will come from harvesting the knowledge of these approaches and networking the results more broadly is the most efficient mechanism to achieve best-practice restoration and resilient project outcomes.
Thesis (Ph.D.) -- University of Adelaide, School of Biololgical Sciences, 2018

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library.
The proliferation of box mistletoe Amyema miquelii in eucalypt woodlands of south-eastern Australia may have resulted from the suppression of canopy fires, a reduction in herbivory by possums, and through environmental change, an improvement in conditions for mistletoe dispersal and establishment. In the Mount Lofty Ranges (MLR), South Australia, box mistletoe is often seen in high numbers in pink gum Eucalyptus fasciculosa woodlands. The following dissertation investigated box mistletoe dispersal and establishment by Mistletoebirds Dicaeum hirundinaceum in a pink gum woodland. The broad aims of the study were to advance our theoretical knowledge of mistletoe dispersal ecology, to understand why pink gum woodlands are more susceptible to mistletoe infection, and to increase the amount of ecological information available to land managers. A survey of box mistletoe and its Eucalyptus hosts in reserves of the MLR region revealed that almost a third of all pink gums were infected with box mistletoe. Individual pink gums with less foliage cover surrounding their canopy were more likely to host box mistletoe, suggesting canopy access for Mistletoebirds may influence the susceptibility of pink gums to mistletoe infection. Woodland type was more influential than fragmentation and edge effects in determining mistletoe presence, indicating a variation in host specificity across Eucalyptus species. The results of this survey indicated that further examination was required on Mistletoebird behaviour and mistletoe establishment success. Two aspects of Mistletoe bird ecology were examined: the influence of their movement patterns on the spatial dynamics of mistletoe dispersal, and their foraging behaviour. Mistletoebirds had home ranges of around 20 ha, and used small core areas (1 ha) of high mistletoe infestation more frequently than areas with lower mistletoe abundance. Modelling of mistletoe seed shadows indicated that the majority of mistletoe seeds (approx. 70%) would be deposited within 100 m of a parent plant. Consistent with this, seed rain modelling showed that mistletoe seed rain was aggregated, with birds dispersing large amounts of seed (> 66 000/ ha) in areas with higher mistletoe infestation levels. This indicated that the movements of mistletoe dispersers promote mistletoe aggregation not only at the scale of an individual tree, but also at a landscape scale. From a management perspective, the results indicated that the removal of mistletoes from single trees may have only short-term results, as reinfection from neighbouring host trees is likely. The attractiveness of pink gums to Mistletoebirds was a function of tree size, mistletoe crop size and tree access. Mistletoebirds preferred to forage in taller trees with a larger mistletoe crop size and which had greater canopy access, and Mistletoebirds most often alighted on dead pink gum when visiting a tree. The results support the notion that woodland dieback may improve conditions for mistletoe dispersal by allowing favourable habitat for Mistletoebirds, by increasing canopy access and by providing more perch sites. Dieback will also reduce mistletoe establishment, however, through a loss of suitable live host branches. The high frequency of box mistletoe infection in pink gum woodlands could also be explained by differences in establishment of box mistletoe between eucalypt species. A mistletoe establishment experiment demonstrated that establishment was significantly higher on pink gums than on E. porosa and E. camaldulensis, and that mistletoes established on pink gums were larger and had a greater number of leaves. The differences probably lay in underlying differences in host physical and chemical defences, and subsequent relative success of mistletoes to establish a functional haustorium. The dispersal syndrome of box mistletoe as described in this study is suitable and perhaps facilitated in the contemporary fragmented environment in a number of ways. These include an ability to concentrate their feeding and breeding activities in small areas of remnant vegetation, greater manoeuvrability between trees isolated by clearing, and easier access to the canopies and perch sites of individual trees in deteriorated woodlands. Priority research stemming from this study should include studies into the underlying causes of pink gum dieback, an experiment to test whether canopy die back directly results in more frequent visitation by Mistletoebirds, an examination of Mistletoebird movements in areas with low mistletoe abundance, and continued monitoring of mistletoe abundance and tree condition as established in this dissertation.
http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1285516
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library.
The proliferation of box mistletoe Amyema miquelii in eucalypt woodlands of south-eastern Australia may have resulted from the suppression of canopy fires, a reduction in herbivory by possums, and through environmental change, an improvement in conditions for mistletoe dispersal and establishment. In the Mount Lofty Ranges (MLR), South Australia, box mistletoe is often seen in high numbers in pink gum Eucalyptus fasciculosa woodlands. The following dissertation investigated box mistletoe dispersal and establishment by Mistletoebirds Dicaeum hirundinaceum in a pink gum woodland. The broad aims of the study were to advance our theoretical knowledge of mistletoe dispersal ecology, to understand why pink gum woodlands are more susceptible to mistletoe infection, and to increase the amount of ecological information available to land managers. A survey of box mistletoe and its Eucalyptus hosts in reserves of the MLR region revealed that almost a third of all pink gums were infected with box mistletoe. Individual pink gums with less foliage cover surrounding their canopy were more likely to host box mistletoe, suggesting canopy access for Mistletoebirds may influence the susceptibility of pink gums to mistletoe infection. Woodland type was more influential than fragmentation and edge effects in determining mistletoe presence, indicating a variation in host specificity across Eucalyptus species. The results of this survey indicated that further examination was required on Mistletoebird behaviour and mistletoe establishment success. Two aspects of Mistletoe bird ecology were examined: the influence of their movement patterns on the spatial dynamics of mistletoe dispersal, and their foraging behaviour. Mistletoebirds had home ranges of around 20 ha, and used small core areas (1 ha) of high mistletoe infestation more frequently than areas with lower mistletoe abundance. Modelling of mistletoe seed shadows indicated that the majority of mistletoe seeds (approx. 70%) would be deposited within 100 m of a parent plant. Consistent with this, seed rain modelling showed that mistletoe seed rain was aggregated, with birds dispersing large amounts of seed (> 66 000/ ha) in areas with higher mistletoe infestation levels. This indicated that the movements of mistletoe dispersers promote mistletoe aggregation not only at the scale of an individual tree, but also at a landscape scale. From a management perspective, the results indicated that the removal of mistletoes from single trees may have only short-term results, as reinfection from neighbouring host trees is likely. The attractiveness of pink gums to Mistletoebirds was a function of tree size, mistletoe crop size and tree access. Mistletoebirds preferred to forage in taller trees with a larger mistletoe crop size and which had greater canopy access, and Mistletoebirds most often alighted on dead pink gum when visiting a tree. The results support the notion that woodland dieback may improve conditions for mistletoe dispersal by allowing favourable habitat for Mistletoebirds, by increasing canopy access and by providing more perch sites. Dieback will also reduce mistletoe establishment, however, through a loss of suitable live host branches. The high frequency of box mistletoe infection in pink gum woodlands could also be explained by differences in establishment of box mistletoe between eucalypt species. A mistletoe establishment experiment demonstrated that establishment was significantly higher on pink gums than on E. porosa and E. camaldulensis, and that mistletoes established on pink gums were larger and had a greater number of leaves. The differences probably lay in underlying differences in host physical and chemical defences, and subsequent relative success of mistletoes to establish a functional haustorium. The dispersal syndrome of box mistletoe as described in this study is suitable and perhaps facilitated in the contemporary fragmented environment in a number of ways. These include an ability to concentrate their feeding and breeding activities in small areas of remnant vegetation, greater manoeuvrability between trees isolated by clearing, and easier access to the canopies and perch sites of individual trees in deteriorated woodlands. Priority research stemming from this study should include studies into the underlying causes of pink gum dieback, an experiment to test whether canopy die back directly results in more frequent visitation by Mistletoebirds, an examination of Mistletoebird movements in areas with low mistletoe abundance, and continued monitoring of mistletoe abundance and tree condition as established in this dissertation.
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007

Land has been extensively modified in response to human needs for thousands of years. In recent times, the change in land use from agricultural areas to tree plantations has been expanding worldwide to satisfy the increasing demands for wood/paper products. In Australia, some areas of cleared agricultural land have been transformed into exotic pine plantations, particularly in New South Wales (NSW). Species occurring in fragments of remnant native vegetation, including birds, may be influenced by the effects of new forms of surrounding land use dominated by exotic Radiata Pine (Pinus radiata) plantations. In this thesis, I sought to quantify how the transformation of landscapes from grazing land to exotic pine plantations influenced the breeding success of small-bodied birds in woodland remnants. I also sought to determine if the results from artificial nests were broadly consistent with those obtained from natural nests. To achieve these aims, I conducted a series of studies of natural and artificial nests in the Nanangroe State Forest and in the surrounding private farmlands in south-eastern NSW, Australia. My study sites were Eucalyptus woodland remnants surrounded by one of two types of matrix; grazing land or maturing stands of Radiata pine plantation. In the natural nest study (Chapter 2), I found significantly fewer nests in woodland remnants surrounded by the plantation than in woodland remnants located in farmland. The proportion of nests of generalist avian nest predators was significantly higher in woodland remnants surrounded by the plantation, compared to woodland remnants surrounded by farmland. In general, I found that breeding success of birds with a larger mean body mass was higher than small-bodied birds, and small-bodied birds reproduced more successfully at a lower nest height. Notably, nesting activity of some forest taxa, including species of conservation concern, was observed both in woodland remnants surrounded by the plantation and in the plantation matrix. In experiments using two types of artificial nests (Chapter 3), I found the following patterns. (1) The majority of nest predators were birds. (2) There were higher levels of nest predation in woodland remnants surrounded by the plantation than in woodland remnants located within farmland, with cup nests being inferior to domed nests against nest predation in the both landscape contexts, and (3) Both natural and artificial nests were more susceptible to nest predation in woodland remnants surrounded by the plantation than in woodland remnants located within grazing paddocks. Overall, my research has shown that land use change from grazing areas to exotic pine plantations may provide more habitats for small-bodied forest species including the Flame Robin (Petroica phoenicea), a vulnerable species in NSW. Conversely, landscape transformation may reduce the amount of habitat for ground-foraging small-bodied woodland birds, such as the Brown Treecreeper (Climacteris picumnus victoriae) and Dusky Woodswallow (Artamus cyanopterus), which are also vulnerable in NSW. Conservation of small-bodied forest versus woodland taxa may require different kinds of management within plantations. However, retaining woodland remnants within the boundaries of plantations benefits a range of kinds of native birds, including forest and woodland taxa.

Dissertação de mestrado em Ecologia, apresentada ao Departamento de Ciências da Vida da Faculdade de Ciências e Tecnologia da Universidade de Coimbra.
As florestas são ecossistemas muito importantes, responsáveis por muitos serviços vitais para os seres humanos, e estão diretamente dependentes da biodiversidade. Porém, as ações humanas têm contribuído para a alteração rápida da composição, estrutura e função da maior parte dos ecossistemas, incluindo das florestas, levando a alterações nos serviços essenciais para a sobrevivência humana. A destruição, alteração e homogeneização das florestas podem ser responsáveis pela perda de espécies e deterioração do funcionamento dos ecossistemas. A coexistência das diferentes espécies vai depender principalmente da disponibilidade de recursos tróficos. As florestas portuguesas dominadas originalmente por Quercus sp. têm vindo a sofrer alterações devido à implementação de agricultura intensiva, e mais recentemente ao abandono agrícola, e à introdução de espécies exóticas, como o Eucalyptus globulus e a Acacia dealbata. Além disso, as florestas passaram a ser geridas pelo Homem o que contribuiu para o aumento de plantações de monoculturas. Espera-se que estas mudanças afetem não só as comunidades vegetais, mas também podem ser altamente negativas para a diversidade e abundancia de artrópodes e assim afetando os restantes níveis tróficos das cadeias alimentares. Neste estudo pretendemos comparar a abundância, diversidade e disponibilidade de recursos primários (i.e. vegetais) e de artrópodes ao longo de um ano em bosques exóticos (plantações de eucaliptos Eucalyptus globulus e bosques de acácias Acacia dealbata) e bosques nativos e naturalizados (bosques dominados por Quercus faginea e plantações de pinheiro-bravo Pinus pinaster, respetivamente). Três tipos de recursos primários: flores, folhas e frutos, foram contabilizados entre janeiro e dezembro de 2014. Além disso, os artrópodes foram amostrados no verão de 2013 e no inverno e primavera de 2014. Verificámos que nos bosques nativos, os recursos primários foram mais diversos, mais abundantes e mais homogeneamente distribuídos no tempo do que nas plantações e nos bosques de acácia. Relativamente aos artrópodes, apenas se registaram-se diferenças significativas na abundância, diversidade e biomassa de artrópodes entre as estações do ano. A biomassa média de artrópodes durante o verão foi bastante mais elevada na floresta nativa, mas a grande variabilidade dos dados impediu que as diferenças fossem significativas. Possivelmente um maior número de estações de amostragem seria importante em estudos futuros, nomeadamente devido à elevada fragmentação dos habitats na área de estudo. Os bosques de acácia e as plantações de eucaliptos produzem um grande número de folhas e flores, altamente concentrados nos meses de inverno. No entanto, tal pico na produção de recursos não foi acompanhado por um aumento na biomassa e riqueza específica de artrópodes. Tal poderá ser explicado pelas condições climatéricas desfavoráveis nesta altura do ano, o que indica que no centro de Portugal o valor em termos de recursos primários que estes bosques e plantações de espécies exóticas podem proporcionar para níveis tróficos superiores é relativamente reduzido.
Forests are very important ecosystems, responsible for many vital services to humans and are directly dependent on biodiversity. However, human actions have contributed to the rapid change in the composition, structure and function of most ecosystems, causing changes in essential services for human survival. The destruction, alteration and homogenization are responsible for the loss of species, and deterioration of forest ecosystem. The coexistence of different species will depend chiefly on the availability of trophic resources. The Portuguese forests originally dominated by Quercus sp. have been suffering changes due to the implementation of intensive agriculture and the introduction of exotic species, such as Eucalyptus globulus and Acacia dealbata. Furthermore, forests started to be managed by Human that contributed to the increase of monoculture tree plantations. These changes can be particularly negative not only for vegetation, but also to the diversity and abundance of arthropods and thus also to other trophic levels of food webs. In this study we will compare the abundance and diversity of primary resources available and arthropods over an entire year in exotic woods (eucalyptus plantations Eucalyptus globulus and acacia woods Acacia dealbata) and native and naturalized woods (woods dominated by Quercus faginea and Pinus pinaster plantations respectively). Three types of primary resources: flowers, leaves and fruits were recorded between January and December (2014) in the three habitats. Arthropods were sampled during summer (2013) and winter and spring (2014). We found that in native woods, primary resources were more diverse, more abundant and more widely spaced in time than in plantations and acacia woodlands. While only season was identified to significantly affect the abundance, diversity and biomass of arthropods. The mean arthropods biomass, during the summer was much higher in native woods, but the large data variability prevented the identification of significant differences. It is possible that a great number of sampling stations would be important in future studies, particularly due to the high fragmentation of the habitats in the study area. We also found that acacia and eucalyptus stands provide a large number of flowers and leaves, largely concentrated on few winter months. However such strong increase in resources was not matched by an increase in the biomass and richness of arthropods, because environmental conditions are much less favorable to arthropods at this time of the year. This suggests that although stands with exotic plant species provide many resources at specific periods of the year in the center of Portugal, these should be little used by higher trophic levels.