Dissertations / Theses on the topic 'Environmental scales'

The simplicity of the Environmental Kuznets (EKC) curve concept motivated this study of the relationships between environmental, economic and social indicators at the country, city/regional and manufacturing facility scale. The study builds on almost 20 years of research on the EKC, which has shown conflicting results for confirmation of the EKC hypothesis that the environment first degrades, then improves, with increasing economic wealth. Most EKC studies use country-scale income or GDP as the primary economic indicator of interest; this study experiments with city/regional GDP at the local scale and a country-scale "market maturity" indicator commonly used by the corporation studied. The manufacturing facility scale analysis is new territory in the EKC literature. Firm-scale studies in the past have been just that, evaluating firm environmental performance across a specific industry. This effort evaluates manufacturing facility performance within the same firm across a set of 21 countries of interest to the corporation. This study is unique in a few other ways. Including multiple scales in the same study is not common in the EKC literature. Typically, a study would focus on one or a few indicators at one specific scale. The actual environmental and social outcome variables used here are also somewhat unique. Generally speaking, the results reported here will fall into the "mixed" bucket relative to the 20 years of existing EKC literature; however, a possible research platform is established based on the possible nesting of multiple scales within the same research effort.

Leadership has been a much studied area within industrial and organizational psychology. Recently, scholars have begun to focus on the negative side of leadership; however, a lack of research has limited our understanding of toxic leadership. One step forward in this domain has been the development of the toxic triangle, which posits that toxic leaders are aided by toxic followers with a toxic environment. Although the leader has been studied within this triangle, relatively little has been researched regarding the follower or the environment. Specifically, that there has been a lack of research in the organizational environment that allows the rise of toxic leaders is concerning. In this study, a toxic work environment scale was developed to help capture pieces of organizational environments that contribute to the rise of toxic leadership. A refined scale was used along with a qualitative piece. Four other scales were used to establish convergent and divergent validity. From the results of this study, although refinement is needed, support for three of the dimensions was found: favoritism, perceived threat, and overall organizational climate. Additionally, through the qualitative portion, additional themes that emerged (e.g., bullying) could be utilized in future use of measures to help assess toxic work environment features. Finally, I recommend that researchers interested in the toxic triangle endeavor to conduct studies that examine all elements simultaneously.

Human activity is causing rapid loss of biodiversity. Although the direct drivers of this are well understood, the indirect socio-economic drivers are not. This thesis examines the role of economic inequality in predicting rates of biodiversity loss at two different scales. First, I perform a cross-national analysis of the proportion of plant and vertebrate species that are threatened, as defined by the IUCN (World Conservation Union) red lists. Second, I examine the role of land cover and socio- economic variables in determining trends in bird species richness in the USA. At the international scale, inequality is consistently an important predictor: the proportion of species threatened is higher in countries that have higher inequality, all else being equal. At the smaller scale of the US, socio-economic variables can explain up to 20% of the variation in species richness. However, inequality does not significantly improve this prediction.
Présentement, l'activité humaine cause une perte rapide de la biodiversité. Alors que les causes directes de cela sont bien comprises, les causes socio-économiques indirectes ne le sont pas. Le rôle des inégalités économiques dans la prédiction des taux de perte de biodiversité sera examiné à deux échelles différentes dans la présente étude. D'abord, il sera question d'une analyse transnationale de la proportion d'espèces végétales et d'espèces vertébrées qui sont menacées, tel que définit par la liste rouge de l'UICN (Union mondiale pour la nature). Ensuite, le rôle de la couverture terrestre ainsi que celui des variables socio-économiques seront examinés afin de déterminer les tendances de l'abondance des espèces aviennes aux États-Unis. À l'échelle internationale et de façon constante, les inégalités sont un prédicteur. À toute autre qualité égale, la proportion d'espèces menacées est plus élevée dans les pays qui ont de plus grandes inégalités. À la plus petite échelle de l'étude, les variables socio-économiques peuvent expliquer près de 20% de la variation. Cependant, l'inégalité économique n'améliore pas considérablement la prédiction.

In this thesis atmospheric and oceanic conditions important for the development of wind storms on different time scales are analysed. The potential usefulness and limitations of seasonal prediction models and long-term reanalyses with respect to wind storm frequency is investigated and sources of potential seasonal predictability of wind storm frequency are discussed. On the synoptic scale tropospheric growth conditions such as baroclinicity, latent heat and upper level divergence show greater magnitudes of one standard deviation on average compared to all extra-tropical cyclones. Mid-latitude Rossby waves show generally greater amplitudes for different wave numbers during wind storm events. Greater amplitudes are also found in wave numbers not typically associated with storm track activity. The analysis of extra-tropical cyclones and wind storms on the seasonal scale reveal positive, significant skill for some European regions in state-of-the-art seasonal prediction models. North Atlantic sea surface temperatures (SST) are shown to be a source of seasonal predictability and a potential reason for the achieved skill for wind storm frequency predictions in reanalysis and AMIP-type sensitivity experiments. The role of tropical Pacific and Atlantic SST for the record number of wind storms over the UK in winter 2013/14 is discussed.

Chemical, textural, and isotopic heterogeneity within granitic magmas/rocks, and their extrusive equivalents, are common phenomena. This is to be expected since the source materials, from which the granitic magmas were created by partial melting, are themselves heterogeneous. Micro-sampling of feldspar crystals within granites has revealed complex internal Sr and Nd isotope variations thought to reveal subtle variations in the isotopic composition of the melt from which particular zones crystallised. These previous studies provide evidence of both macro-scale (regional) and micro-scale isotopic variation within granitic magmas. What is unknown is the scale and nature of chemical and isotopic variation occurring on the meso-scale (metre, decametre, hectometre). In this study, high-precision geochemical and isotopic (Sr, Nd, and O) data is obtained for spatially well-constrained samples, from three granitic intrusions from the UK, to study the scales over which isotope heterogeneities are preserved, and the maximum volumes of magma over which isotope and elemental homogenisation may have been achieved. This information provides important constraints on the physical and chemical characteristics of processes that occur during magma genesis, ascent, and emplacement. The regional-scale geochemical and isotopic heterogeneity in the Criffell pluton (SW Scotland) has been well documented and ascribed to 'incomplete hybridisation' between magmas derived from the melting of mantle and/or 'new' basic crust and metasediments. Sampling on the 10 to 100 m scale in this study demonstrates major-, trace- and rare earth element homogeneity between samples of similar petrography. Within the Dalbeattie Quarry granodiorite, subtle heterogeneity in initial ([sup]87Sr/[sup]86Sr)[sub]397 Ma compositions exist (0.70582 to 0.70615), between samples collected ~ 150 m apart. The small-scale heterogeneity is outside of analytical error (± 0.0001). [delta][sup]18O heterogeneity also occurs on similar small scales (~ 120 m), with values ranging from 8.9 to 10.7 %. The larger error on the [epsilon][sub]Nd(397 Ma) values do not allow any small-scale heterogeneity to be resolved. The geochemical and isotopic heterogeneity of the Cairnsmore of Fleet pluton, another Southern Upland granite, is also well known, and considered to be a result of similar processes to that of Criffell. This study demonstrates that the Cairnsmore granite is more petrographically variable in terms of grain-size, mafic/felsic mineral proportions, and accessory mineral assemblages over scales ranging between 100 and 350 m. The existence of more petrographic and geochemical heterogeneities on smaller scales suggests that homogenisation processes were less effective in this pluton compared to Criffell. On scales < 1 km, ([sup]87Sr/[sup]86Sr)[sub]392 Ma compositions and [epsilon][sub]Nd(397 Ma) values are essentially homogeneous. Forest Track samples PAHCF23 (0.70796) and PAHCF25A (0.70672) are ~ 1 km apart and can only just be distinguished outside of analytical error. However, [delta][sup]18O data demonstrate the existence of both regional-scale and locality-scale [delta][sup]18O heterogeneity on the 100 m, decametre and even cm-scale (8.3 to 9.7%0, error ± 0.1%0). The two main granite varieties of the Dartmoor pluton (SW England) are generally, homogeneous in terms of their petrography and geochemistry on 100 m, decametre, meter and even cm scale. However, isotope heterogeneity, outside of analytical error is shown to exist on even the cm-scale. The samples PAHD34A and P AHD34B, from Blackenstone Quarry, have ([sup]87Sr/[sup]86Sr)[sub]280Ma compositions of O.70949 and 0.71292 respectively, and were collected 50 cm apart. Samples PAHD35A and PAHD35B have ([sup]87Sr/[sup]86Sr)[sub]280 Ma compositions of 0.70960 and 0.71205, and were collected 100 cm apart. Variation in [delta][sup]18O and [epsilon][sub]Nd(280 Ma) values also exist. PAHD34A and PAHD34B have [delta][sup]180 compositions of 10.01 and 10.98 %0 (± 0.1%0), and SNd(280 Ma) values of -3.8 and -3.3 (± 0.2), respectively. Either the distinct magma batches, that coalesced to form the pluton, were much smaller in Dartmoor (compared to the Criffell and Cairnsmore plutons), or these heterogeneities may represent volumes of magma, within larger domains, that escaped homogenisation by mixing and diffusion. The existence of discrete, isotopically distinct batches of magma within the Criffell, Cairnsmore and Dartmoor plutons favours the dyke model for granitoid magma ascent through a pulsed magma delivery, in which separate magma batches (or pulses) coalesce to form plutons at or near their final emplacement levels. The scale over which such magma pulses can still be recognised varies within each pluton. The magma pulses are likely to have been larger in size, but subsequent homogenisation processes in the chambers led to a reduction in their size. However, homogenisation was not complete. In all three plutons, it is generally only the isotope ratios that display significant small-scale heterogeneity. Processes such as fractional crystallisation, are considered to be secondary, overprinting geochemical and isotopic heterogeneity from much deeper regions.

Temporal changes in the environmental conditions upon which life depend are ubiquitous in nature, acting at every level of organisation from cells to ecosystems. Although the actions themselves are often poorly understood, they strongly depend on the temporal and hierarchical (organisational) scales at which they are measured; ecosystems are relatively stable through time while their species composition may undergo vast changes. Likewise any hierarchical level may be relatively stable in the short-term, but undergo vast long-term changes. This thesis aims to better understand the importance of these scales for mediating the impact of environmental variability on ecological systems.
The approach used herein employs both mathematical models and empirical data which represent food webs responding to environmental variability at different hierarchical scales. Within each of these representative food webs, the influence of environmental variability on the stability of the food web is determined using an approach which accounts for the effects of temporal scale. This thesis demonstrates that the stability of simple model food webs (high hierarchical scale) is tightly linked to environmental variability and the temporal scales at which these changes occur dictate which species in the model are most affected. At lower scales of organisation, empirical data indicate that environmental variability generally has a lesser impact on stability and that only certain temporal scales are responsible for this trend. At these temporal scales some species respond differently to environmental variability, negative changes in one species (or group) are offset by positive changes in another - a process known as compensation. These results highlight the importance of both temporal and hierarchical scale in mediating the response of food webs to environmental variability. Ultimately, they will serve to better understand how models and experiments should scale-up from low to high hierarchical and temporal scales.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 163-171).
Across scales ranging from individual blades to river reaches, the interaction between water flow and vegetation has important ecological and engineering implications. At the reach-scale, vegetation is often the largest source of hydraulic resistance. Based on a simple momentum balance, we show that the resistance produced by vegetation depends primarily on the fraction of the channel cross-section blocked by vegetation. For the same blockage, the specific distribution of vegetation also plays a role; a large number of small patches generates more resistance than a single large patch. At the patch-scale, velocity and turbulence levels within the canopy set water renewal and sediment resuspension. We consider both steady currents and wave-induced flows. For steady flows, the flow structure is significantly affected by canopy density. We define sparse and dense canopies based on the relative contribution of turbulent stress and canopy drag to the momentum balance. Within sparse canopies, velocity and turbulent stress remain elevated and the rate of sediment suspension is comparable to that in unvegetated regions. Within dense canopies, velocity and turbulent stress are reduced by canopy drag, and the rate of sediment resuspension is lower. Unlike steady flows, wave-induced oscillatory flows are not significantly damped within vegetated canopies. Further, our laboratory and field measurements show that, despite being driven by a purely oscillatory flow, a mean current in the direction of wave propagation is generated within the canopy. This mean current is forced by a wave stress, similar to the streaming observed in wave boundary layers. At the blade-scale, plant-flow interaction sets posture and drag. Through laboratory experiments and numerical simulations, we show that posture is set by a balance between the hydrodynamic forcing and the restoring forces due to blade stiffness and buoyancy. When the hydrodynamic forcing is small compared to the restoring forces, the blades remain upright in flow and a standard quadratic law predicts the relationship between drag and velocity. When the hydrodynamic forcing exceeds the restoring forces, the blades are pushed over in steady flow, and move with oscillatory flow. For this limit, we develop new scaling laws that link drag with velocity.
by Mitul Luhar.
Ph.D.

Modern agriculture has led to fundamental changes in the phosphorus (P) cycle that pose agronomic and environmental challenges at all scales. Phosphorus is a non-renewable resource that is critical to food production because of its role as an essential plant nutrient. At the same time, P runoff from agricultural systems contributes to water quality degradation worldwide. Recent research has begun to illuminate the dimensions of P use in agriculture and its broader sustainability implications, yet there is limited understanding of how these disparate issues are connected across scales. In this thesis, I explore important knowledge gaps related to spatial and temporal changes in P flows due to human activity, their drivers, and some of the implications for large-scale management of soil P and water quality. With the first study, I conducted a global analysis to better understand the contemporary distribution of agronomic P use for croplands. The spatially detailed results revealed that disparities in the magnitude of P applied to cropland soils as fertilizer and manure relative to crop P use occur across most regions, but with considerable spatial variation. Although inputs of P fertilizer (14.2 Tg of P/yr) and manure (9.6 Tg of P/yr) collectively exceeded P removal by harvested crops (12.3 Tg of P/yr) at the global scale, P deficits covered almost 30% of the global cropland area. I then present a comprehensive analysis of the United States agricultural system, exploring how globalization exacerbates changes to regional P cycling. This study considered how limited national P fertilizer supplies are allocated at the interface between trade, biofuel production, and diets. Total mineral P used in the US can be traced predominantly to accumulation in domestic agricultural soils (28%), post-harvest losses (40%), or biofuel refining (10%). Only 8% of mineral P use was ultimately consumed in domestic diets, while one quarter of domestic P fertilizer use was allocated to producing exports. In turn, agriculturally-driven changes in soil P pools could have long-term ecological implications given the slow cycling of P in some soils. I conducted a comprehensive meta-analysis to assess evidence for these legacy effects throughout the world, indicated by either enriched or depleted soil labile and total P pools following agricultural abandonment. This global meta-analysis revealed potentially large and enduring legacies of past agriculture on soil P pools across different regions and soil types, but with some reduction in the magnitude of these changes over time since abandonment. Finally, I considered the roles of watershed anthropogenic and biophysical characteristics on P loading to lakes to aid in the development of large scale lake eutrophication risk models. I used a multi-faceted statistical approach with recent global land use and hydrological data to predict lakewater total phosphorus (TP) concentrations across a representative sample of >1000 lakes worldwide. Global lake TP predictions from three unique statistical methods explained from 50% to as much as 79% of the variation in observed TP, with relatively low error rates. Collectively, this work sheds new insight on agricultural modifications to the global P cycle arising from past and present nutrient management as well as how these might influence both soil P pools and water quality over time. There is growing need to balance local context (e.g., soil types, management histories, and livestock densities) with the cumulative implications these have on limited P reserves at the national or global level (e.g., closing regional P imbalances and accounting for the effects of trade). Greater attention to the spatial variation in both problems and solutions related to P, as well as their complex temporal dimensions, will be essential for advancing the science and policies needed to achieve greater P sustainability in agriculture while simultaneously ensuring healthy aquatic ecosystems.
L'agriculture moderne a fondamentalement changée le cycle du phosphore (P) d'une façon qui dorénavant pose des défis agronomiques et environnementaux à toutes les échelles. Le P est une ressource non renouvelable qui est d'une importance cruciale à la production alimentaire car c'est essentiel pour les plantes. En même temps, les pertes de P à partir des terres agricoles dans l'eau de ruissellement contribuent à la dégradation de la qualité de l'eau dans le monde entier. J'explore des lacunes importantes au niveau de nos connaissances liées aux changements spatiaux et temporels dans le mouvement du P due à l'activité humaine, leurs causes, et quelques-unes des implications pour la gestion du P dans le sol et de la qualité de l'eau à grande échelle. Premierement, j'ai effectué une analyse à l'échelle globale sur les implications de l'utilisation du P agronomique sur les sols agricoles et sur la distribution actuelle du P dans les sols agricoles. Les résultats spatiaux démontré qu'il y a une disparité entre la quantité de P appliqué aux terres agricoles comme engrais chimiques et comme fumier et le P incorporé dans les récoltes agricoles dans la plus part des régions du monde, mais que l'ampleur de cette disparité varie considérablement entre ces régions. Bien qu'à l'échelle global l'application de P comme engrais (14,2 Tg P/an) et comme fumier (9,6 Tg P/an) collectivement dépasse le P incorporé dans les récoltes agricoles (12,3 Tg P/an), un déficit de P est présent sur près de 30% de la superficie mondiale des terres cultivées. J'ai ensuite effectué une étude approfondie du système agricole des États-Unis et ses partenaires commerciaux afin de comprendre comment la mondialisation exacerbe les changements dans le cycle du P régionale. Le P minéral utilisé aux États-Unis peut être tracée principalement à une accumulation dans les sols agricoles domestiques (28%), les pertes après la récolte (40%), ainsi que la production de bio carburant (10%). Seulement 8% de ce P minéral a été consommée comme nourritures aux Etats-Unis, mais un quart de la demande national d'engrais de P a été alloué à la production d'exportations. Les changements causés par agriculture sur les réservoirs de P dans sols pourraient également avoir des implications écologiques à long terme contenu de la lente vitesse à laquelle le cycle du P a lieu dans certains sols. J'ai mené une méta-analyse exhaustive des études existantes pour comprendre le rôle de l'héritage de présence de culture agricoles sur les réservoirs de P dans des sols après l'abandon agricole à travers le monde. Finalement, j'ai considéré les facteurs anthropologiques déterminants l'accumulation de P dans les lacs en comparaison avec le rôle des caractéristiques biophysiques des bassins versants afin d'aider à l'élaboration de modèles sur le risque d'eutrophisation. J'ai utilisé une approche à multiples facettes statistique pour prédire les concentrations de phosphore total (PT) pour d'un échantillon (> 1000) de lacs dans le monde entier, à partir de cartes d'utilisation des terres mondiale et de données hydrologiques courante. Mondialement les prédictions de PT dans les lacs, à partir de trois approches statistiques uniques, expliquent entre 50% et 79% de la variation observée dans le PT. Collectivement, ce travail illustre comment les modifications agricoles du cycle du P mondiale peuvent être comprit en examinant la gestion du P dans le passé et le présent ainsi que la façon dont cette gestion peut influencer les réserves du P dans les sols et la qualité de l'eau à travers le temps. Une plus grande attention à la variation spatiale dans les deux dimensions de cette problématique et les solutions liés au P, ainsi que leurs dimensions temporelles complexes, sera essentielle pour faire progresser à la fois la science et les politiques nécessaires pour parvenir à une plus grande durabilité dans la gestion du P dans l'agriculture tout en veillant à la santé des écosystèmes aquatiques.

Thesis: Ph. D. in Environmental Chemistry, Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 123-135).
As concern grows over increasing human population and the effects of industrialization on the environment, agriculture and air quality have become important areas of research. Both are vital to human prosperity, determining what we eat and what we breathe. The interactions between agriculture and air quality (defined by ozone and particulate matter (PM) concentrations) are many and often poorly understood. This thesis examines their interactions in two parts. First, we investigate the influence and characterize the importance of the variability in agricultural ammonia emissions on surface inorganic fine PM (PM₂.₅). In a case study, airborne observations indicate that summertime concentrations of ammonia throughout California and PM₂.₅ in Los Angeles are underestimated in a global chemistry model (GEOS-Chem) used to understand air quality issues. We find that increasing ammonia emissions from livestock and fertilizer allows the model to better represent the observations, thereby improving the model's prediction of PM₂.₅ conditions in wintertime, when concentrations and impacts on human health are greater. We also use new observations (surface, aircraft, and satellite) to find that the model underrepresents the summertime ammonia concentration near large source regions throughout the United States. Meteorology dominates the underestimated year-to-year variability in the model over reductions in acid-precursors. Introduction of varying ammonia emissions does not improve the model comparison and has little impact on PM₂.₅. Second, we quantify the impact of air quality on global crop production under current and future emissions scenarios. Using a relativistic approach, we find that the maximum positive impact (highly uncertain) from total PM light scattering can outweigh the negative impact from ozone damage in certain crops and regions. Future scenarios indicate that reductions in air pollution may have a net negative effect on crop production in areas dominated by the PM effect. We then employ a crop model (pDSSAT) to more realistically predict the lessened impact of PM under stress from resource restrictions. We also assess the effect of nitrogen deposition on crops compared to PM. Overall, we highlight the need for better observations of both ammonia concentrations and the impacts of PM on crop growth to reduce uncertainty in these interactions.
by Luke D. Schiferl.
Ph. D. in Environmental Chemistry

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1994.
Includes bibliographical references (leaves 252-263).
by Ede Jorge Ijjász-Vásquez.
Ph.D.

The deep sea is the Earth’s largest ecosystem and harbors a unique and largely endemic fauna. Although most research has focused on the ecological mechanisms that allow coexistence, recent studies have begun to investigate how this remarkable fauna evolved.. My work quantifies geographic patterns of genetic variation and investigates potential mechanisms that shape evolution in the deep ocean.

Bathymetric genetic divergence is common in the deep sea with population structure typically decreasing with depth. The evolutionary mechanisms that underlie these patterns are poorly understood. Geographic patterns of genetic variation indicated that the protobranch bivalve Neilonella salicensis was composed of two distinct lineages separated bathymetrically. Genetic diversity was greater in the lower-bathyal clade of N. salicensis than the upper to mid-bathyal clade. In a co-occurring mid-bathyal protobranch Malletia johnsoni, population differentiation was greater among samples than the confamilial lower-bathyal Clencharia abyssorum, though, genetic diversity was similar. These patterns suggest general trends do not always hold and fine scale patterns of gene flow need to be thoroughly investigated.

Little is known about the ecological or evolutionary mechanisms that might promote divergence or maintain population structure. Oxygen minimum zones (OMZs), which cover enormous regions of the deep ocean, might hamper gene flow by precluding larval dispersal. To test this, genetic patterns of the wood-boring bivalve Xylophaga washington were quantified across the northeastern Pacific OMZ. Results indicate two clades were apparent, one throughout the OMZ and one within and below it, possibly segregated by a historically stronger OMZ or other environmental factors that vary with depth. A similarly uninvestigated evolutionary factor with potentially large impacts is selection on mitochondrial DNA. Positive selection is apparent in the mitochondrial DNA of shallow water and deep-sea crabs, shrimp, and fishes, possibly related to any of the myriad factors that differ between the two habitats.

The deep sea is biogeochemically important and is highly impacted by climate change and anthropogenic factors. Genetic patterns in this habitat are very complex. This work suggests gene flow is inhibited at many scales, both across bathymetric gradients and within small bathymetric ranges.

This research has analysed the large sandy beach at Studland Peninsula over a range of spatial and temporal scales, recording a range of geomorphic features and the processes by which they evolve. The aim was to understand better the morphodynamic evolution of the coastal system over different temporal and spatial scales and identify the extent of changes operating along the beach system. The research has sought to quantify shoreline change from the historical archive by providing an interpretation of the evolutionary sequence of the Studland system over the last 500 years. The linkage between the ebb tidal delta and shoreline progradation has been reviewed. In addition,the temporal variability of the beach system between 2001 and 2004 has been examined. These objectives have been combined to produce a nested hierarchy of spatial and temporal change in the Studland system in order to re-evaluate already existing conceptual models of sediment transportand process. Historic change within the system has been undertaken by a review of historic maps, charts and aerial photographs. Ground Penetration Radar was used to determine the subsurface stratigraphy, providing an indicator of the extent of onlapping and offlapping sand sheets and an interpretation of the morphostratigraphy. Swath bathymetry was used to examine contemporary seabed change within Studland Bay. Regular beach profiles provided datafora time series analysis to be applied to determine temporaland spatial beach behaviour. This study has contributed to furthering the understanding of beach systems by providing a comprehensive overview of beach behaviour on a variety of levels, from the littoral cell to a morphological feature. The study has progressed the understanding of beach sensitivity, and the interplay between ebb tidal deltas and beaches.The results reveal that the Studland Beach system operates as a nested hierarchy of scales, responding to a range of timescales from the historical to the annual. Morphological changes operate at high and low frequencies. The historical trend is for foreshore progradationin the north and erosion in the south. The pattern of variability revealed the importance of sediment feed from the ebb tidal delta to the beach,confirmingthe Poole Harbour entrance is a major contributor to foreshore change. The decadal trends illustrate an accumulation of short-term trends with on and off shore sediment feed via the ebbtidal delta; beach change is muted or hidden by more dynamic frequency variations. Conceptual models were developed to understand geographical relationships between form, process and scale, thus illustrating the relationships between controlling variables, temporal and spatial beach form variability and the system's hierarchy. Profile variability revealed several distinct patterns of spatial and temporal change, enabling discrete sets of profiles to be grouped together to illustrate the complicated relationship caused by geographical and spatial profile variation. Wider beaches with greater profile variability signified stability and accumulation. Scarcity of morphologicalfeatures reflected greater susceptibility to erosion. Furthermore,the study allowed morphological variability to be mapped out, thus providing a complete understanding of the relationships between form and process, at a level of scales never undertaken before.The models have revealed a compartmentalised hierarchical sediment system related to the survivability of beach features; morphological variability and beach stability,linking the components of the system with the whole of the Bournemouth Bay littoral cell.

Selenium (Se) is a trace element of great ecological importance whose environmental distribution is highly impacted by anthropogenic activity. In the 1980s, selenium was recognized as a major aquatic contaminant following widespread deformities and mortality among waterfowl hatchlings near the agricultural drainage evaporation ponds of the Kesterson Reservoir (CA, USA). Today, 400,000 km² in the Western United States are threatened by agricultural selenium contamination, as are parts of Canada, Egypt, Israel, and Mexico. From the soil aggregate to the watershed, from the soils of the Central Valley to the sediments of the Salton Sea, and from Environmental Science to Policy and Management, in this dissertation I explore agricultural selenium contamination across scales, ecosystems, and disciplines. I begin with a review of the science, policy, and management of irrigation-induced selenium contamination in California, the heart of worldwide research on the issue. I then delve into the physical and biogeochemical mechanisms that control selenium reduction and mobility within the structured surface soils that are the source of contamination, using an aggregate-scale combined experimental and reactive transport modeling approach. Finally, I present a diagenetic model for selenium incorporation into the sediment of the Salton Sea, which has been receiving seleniferous agricultural drainage over the last 100 years.

To extract lessons from the last 30 years of seleniferous drainage management and water quality regulation in California, I reviewed the history and current developments in science, policy, and management of irrigation-induced selenium contamination in California. Specifically, I evaluated improvements in the design of local attenuation methods and the development of programs for selenium load reductions at the regional scale. On the policy side, I assessed the site-specific water quality criteria under development for the San Francisco Bay-Delta in the context of previous regulation. This approach may be a landmark for future legislation on selenium in natural water bodies and I discussed challenges and opportunities in expanding it to other locations such as the Salton Sea. By combining proven management tools with the novel, site-specific policy approach, it may be possible to avoid future events of irrigation-induced selenium contamination. However, the majority of regional selenium load reductions in California were achieved by decreasing drainage volume rather than selenium concentrations. Thus, there appear to be opportunities for additional improvements through management practices that enhance selenium retention in source soils.

To quantify the likely implications of these experimental results for soils with different degrees of aggregation, I formulated a general mechanistic framework for aggregate scale heterogeneity in selenium reduction. Specifically, I constructed a dynamic 2D model of selenium fate in single idealized aggregates, in which reactions were implemented with double-Monod rate equations coupled to the transport of pyruvate, O₂, and Se-species (selenate, selenite, and elemental selenium). The spatial and temporal dynamics of the model were validated with the experimental data and predictive simulations were performed covering aggregate sizes between 1 and 2.5 cm diameters. Simulations predict that selenium retention scales with aggregate size. Depending on aeration conditions and the input concentrations of selenate and pyruvate, selenium retention was predicted to be 4-23 times higher in 2.5-cm-aggregates compared to 1-cm-aggregates. Under oxic conditions, aggregate size and pyruvate-concentrations were found to have a positive synergistic effect on selenium retention. Promoting soil aggregation on seleniferous agricultural soils may thus help decrease the impacts of selenium contaminated drainage on downstream aquatic ecosystems receiving it.

This work presents agricultural selenium contamination as a complex problem that crosses ecosystems, scales, and disciplines. From a management perspective, the tension between dispersed non-point sources and hotspots where elevated selenium concentrations and sensitive aquatic ecosystems converge is difficult to address. Differences in biogeochemical conditions and trophic transfer within food webs render traditional regulatory approaches ineffective and force regulators to engage with the science of site-specific selenium transfer between ecological compartments. At the same time, gaps still exist in our mechanistic understanding of selenium's environmental cycling and in our integration of scientific knowledge across different ecosystems and scales. Centimeter scale heterogeneity in the biogeochemical conditions within source soils may fundamentally control selenium emissions across large agricultural areas and thus determine the selenium loading of rivers, lakes, and estuaries. Within aquatic environments receiving seleniferous drainage, the first few centimeters of surface sediment may control selenium exposure for entire food webs. Improved understanding at this level holds the potential to simultaneously reduce selenium emissions and respond more effectively to pollution where it occurs. In order to preserve sensitive habitat while also meeting agricultural drainage needs in seleniferous regions we must bridge the gaps between ecosystems, scales, and disciplines.

(Abstract shortened by UMI.)

This dissertation examines the politics of knowledge in collaborative watershed governance institutions of the Klamath River Basin of Northern California and Southern Oregon. The waters of the Klamath are shared between farmers, fisherfolk, indigenous communities, hydro-electric facilities and one of the most biologically diverse eco-regions in the United States. Since 1986, the watershed has provided the primary spatial unit for resolving resource conflict by coordinating agency and citizen science, guiding integrated resource management and cultivating a shared sense of place and belonging among Klamath watershed inhabitants. For nearly three decades, the Klamath Basin has served as a laboratory for experiments in “watershed democracy”- a form of hydrologically-grounded political association that attempts to facilitate the direct participation of all watershed inhabitants in knowledge production, deliberation and collective action at the watershed scale. Through the idiom of watershed democracy, I connect empirical research on the outcomes of nearly three decades of community-based natural resource management in the Klamath with theoretical debates waged over the last century and a half regarding the question of scale in environmental science, democratic governance and natural resource management.

In this dissertation, I analyze the watershed as a scale of knowledge production, a site of democratic deliberation and a unit of environmental governance. I investigate whether the watershed is the most appropriate socio- spatial unit for representing people and place in the Klamath, paying particular attention to the impact of collaborative watershed governance arenas on the ability of Karuk Tribal members to participate in knowledge-production and decision- making for natural resource management in their ancestral territory in northern California.

Through participatory research with the Karuk Tribe’s Department of Natural Resources, participant observation, document analysis and interviews with Federal, State, Tribal and local agency scientists and representatives, I follow knowledge and policy-making processes across a diverse range of institutions engaged in Klamath watershed governance. Combining participatory research and participant observation with theoretical insights from political ecology, science and technology studies (STS) and indigenous studies scholarship, I evaluate the processes and outcomes of collaborative watershed-based governance according to its impacts on local watershed ecosystems and communities. Drawing on the theoretical framework of “co-production”, I analyze the mutually constitutive relations between watershed science, watershed governance institutions, the materialities of Klamath watershed-ecosystems and the distributions of resource benefits and burdens in Klamath communities. I follow Klamath experiments in watershed democracy negotiate the basic terms of political life such as property, territory, sovereignty and the public good, as well as the material conditions and flows of watershed resources and the patterns of access to, ownership in and distribution of these resources.

While the Klamath experiements in collaborative environmental governance at the watershed scale have opened up oppportunities for Karuk representatives to participate in knowledge production and decision-making, the watershed scale has itself constrained the focus of integrated resource management, limiting the kinds of knowledge that can pattern as reliable and the types of restoration and management projects that can issue from Klamath collaborative governance forums. I demonstrate how Karuk representatives have both leveraged and critiqued the watershed as a way of conceptualizing Klamath watershed-ecological processes and as a socio-spatial unit for approaching ecological restoration and cultural revitalization in their ancestral territory. Watershed science and watershed governance forums were sometimes leveraged by Karuk representatives to substantiate Karuk sovereignty and resource rights and at times rejected for not being able to convey distinct Karuk epistemologies, ontologies and cosmologies. I demonstrate how collaborative watershed management forums have struggled to render different types of indigenous, local and scientific knowledge commensurable and have instead provoked debates about how to produce knowledge about nature in ways that are appropriate for the local community and its ecosystems.

I draw attention to the cultural politics of scale to critique watershed-centric management and search for alternative ways of representing the multiple scales through which Klamath inhabitants understand and value nature. I compare watershed-based governance with two other emerging scales of democratic resource governance- firesheds and foodsheds- in their abilities to bring together diverse forms of environmental knowledge around multiple nested scales of social and ecological processes. Firesheds are emerging areas of community-based fire management patterned according to the way fire burns across the western Klamath landscape. Foodsheds are another emerging form of community-based resource governance taking shape in the Klamath around the spatial and temporal characteristics of food resources and their associated management practices in forest ecosystems. Comparing watersheds, firesheds and foodsheds opens up the question of scale in collaborative environmental governance by highlighting tensions among different ways of producing knowledge, managing resources and acting collectively at different bioregional scales in the Klamath.

Against watershed-centric approaches to ecological democracy, I argue for deliberative multi-scalar approaches to implementing collaborative environmental governance, cultural revitalization and watershed-ecosystem restoration in the Klamath. Multi-scalar perspectives can accommodate multiple ways of making knowledge while avoiding homogenizing diverse situated perspectives into a single way of seeing Klamath eco-cultural landscapes. I argue for “democratizing scale” in order to define an appropriate scalar framework for producing knowledge, representing human values and making decisions about the management of natural resources. Collaborative environmental governance requires an accompanying democratization of scale to accommodate the myriad ways of knowing nature and making a living in Klamath watershed-ecosystems. Scalar formations that are produced through deliberative democratic processes can provide more inclusive grounds than watersheds for democratic environmental governance and multispecies world-making.

Mazama, Washington is a small community, with a population of 230 residents, nestled in the Methow Valley near the North Cascades mountain range. Mazama is home to delicate ecosystems, thriving wildlife, a river integral to salmon recovery, and a local economy that is largely dependent on outdoor recreation. Also home to Mazama is an environmental campaign, brought forth by community-wide resistance to industrial mining proposals in the valley. The campaign, called the Methow Headwaters Campaign, is advocating for the protection of 340,079 acres of federal land from mineral withdraws. The campaign mobilized following an exploratory drilling proposal by a Canadian industrial-scale mining company, Blue River Resources Ltd, to mine on Flagg Mountain—a mountain located less than two miles from the town of Mazama. Because of the Mining Act of 1872, Blue River Resources Ltd. can earn one-hundred-percent interest from the Flagg Mountain project, while the Mazama community—largely based on a local recreational economy—bears the social, environmental, and economic burdens brought with these mining operations. This thesis examines how natural resource governance has been shaped in the Methow Valley at various scales, ultimately resulting in the social contestation of extractive development in Mazama in the early 21st century. This thesis argues that the community-led campaign to withdraw land from mineral withdraws attempts to “re-scale” environmental governance through a democratizing shift in political and ecological control.

Thesis (PhD)--Stellenbosch University, 2011.
ENGLISH ABSTRACT: Dragonflies (Insecta: Odonata) are a valuable tool for assessing aquatic systems and have been used as indicators of ecological health, ecological integrity, and environmental change, including climatic change. In four separate studies I explored the usefulness of dragonflies as surrogates in biomonitoring, site prioritization and indication of global climate change. In the use of dragonflies for biomonitoring, I field-tested a freshwater ecological integrity index, the Dragonfly Biotic Index (DBI), based on dragonfly assemblages at the local scale, and compared the DBI to a standard freshwater benthic macroinvertebrate-based freshwater health index. Overall, dragonflies were more sensitive to changes in river condition than were macroinvertebrates, and the DBI site value and macroinvertebrate scores were highly significantly correlated. I conclude that dragonfly assemblages in the form of a DBI are an excellent tool for environmental assessment and monitoring freshwater biodiversity, with the potential to replace benthic macroinvertebrate-based freshwater quality assessments. In the second study, I used the DBI to prioritize sites for conservation action in South Africa. Using a selected set of top prioritized sites, I compared the DBI’s performance to that of a rarity-complementarity algorithm. Site prioritization using the DBI reveals that CFR sites protect Red Listed taxa rather well. The rarity-complementarity algorithm represents all species, but without greater emphasis on the rare and threatened species. I conclude that the DBI is of great value in selecting biodiversity hotspots, while the algorithm is useful for selecting complementarity hotspots. The third study was made possible by the recent completion of a continental assessment of freshwater biodiversity, which revealed that patterns of richness and threat of four well-studied aquatic taxa largely coincide at the continental scale. Using only dragonflies, I built a protected areas network for Africa using spatial planning software. I then compared the performance of the existing African reserve network and that of known global biodiversity hotspots against the model, and identified sites of conservation concern. Although the current reserve network covers 10.7% of the landscape, the proportional representation of species geographic distributions in reserves is only 1.1%. The reserve network is therefore inefficient, and many areas of conservation priority that are not formally protected remain. The advantage of operating at the fine scale, while covering a large geographic area is that it shifts the focus from the large-scale hotspots to smaller priority areas within and beyond hotspots. In the fourth study, I created species distribution models of dragonflies in an El Niño-prone biodiversity hotspot in South Africa, and predicted the changes in species richness, geographic range and habitat suitability, forty and eighty years from now. According to the model results of two different emissions scenarios, at least three species will be lost from the area by 2050, and four by 2080. The remaining species are predicted to persist with reduced geographical ranges, at generally higher elevations. Most species presented here thrive quite well in artificial environments, that is, engineered ponds or dams. It is therefore unlikely that loss in connectivity will play a role for these species.
AFRIKAANSE OPSOMMING: Naaldekokers (Insecta:Odonata) is waardevolle instrumente om akwatiese sisteme te assesseer, en is al gebruik as aanwysers van ekologiese gesondheid, ekologiese integriteit en omgewingsverandering, insluitend klimaatsverandering. In vier studies het ek die nut van naaldekokers as surrogate in biomonitering, area prioritisering en indikasie van globale klimaatsverandering ondersoek. In die benutting van naaldekokers in biomonitering, het ek ´n varswater ekologiese integriteits indeks, die Dragonfly Biotic Index (DBI), wat gebaseer is op naaldekokergemeenskappe op die plaaslike skaal, getoets en dit vergelyk met ´n standaard bentiese makroinvertebraat-gebaseerde varswater gesondheids index. Naaldekokers was meer sensitief vir veranderinge in riviertoestand as makroinvertebrate, en die DBI lokaliteit waarde en makroinvertebraat telling was beduidend gekorreleer. Die gevolgtrekking was dat naaldekoker gemeenskappe in die vorm van die DBI ‘n uitstekende instrument is vir omgewings assessering en die monitering van varswater biodiversiteit, met die potensiaal om bentiese makroinvertebraat-gebaseerde varswaterkwaliteit assessering te vervang. In die tweede studie, het ek die DBI gebruik om areas te prioritiseer vir bewaringsaksie in Suid Afrika. Met die gebruik van ‘n geselekteerde set top prioriteit areas, het ek die DBI se prestasie vergelyk met die van ‘n rariteit-komplemetariteit algoritme. Area prioritisering met die gebruik van die DBI het aangedui dat CFR areas taxa op die Rooi Lys goed beskerm. Die rariteit-komplementariteit algoritme verteenwoordig alle spesies, maar beklemtoon minder skaars en bedreigde spesies. Die gevolgtrekking was dat die DBI van meer waarde is in die selektering van biodiversiteits ‘hotspots‘, terwyl die algoritme nuttig is vir die selektering van komplementariteits ‘hotspots‘. Die derde studie was moontlik gemaak deur die onlangse voltooiing van ‘n kontinentale assessering van varswater biodiversiteit, wat aangedui het dat patrone van rykheid en bedreiging van vier goed-bestudeerde akwatiese taxa grootliks ooreenstem op die kontinentale skaal. Met die gebruik van naaldekokers, het ek ‘n beskermde area netwerk gebou vir Afrika met ruimtelike beplannings sagteware. Ek het die prestasie van die bestaande Afrika reservaatnetwerk en die van bekende globale biodiversiteit ‘hotspots‘ vergelyk teen die model, en het areas van bewaringsbelang geidentifiseer. Alhoewel die bestaande reservaatnetwerk 10.7% van die landskap dek, is die proporsionele verteenwoordiging van spesies se geografiese verspreiding net 1.1%. Die reservaatnetwerk is dus onvoldoende en baie areas van bewaringsbelang is nie formeel beskerm nie. Die voordeel van op die fyn skaal werk terwyl ‘n groot geografiese are gedek word, is dat dit die fokus van groot skaal ‘hotspots‘ na kleiner prioriteits areas binne en buite ‘hotspots‘ verskuif. In die vierde studie, het ek spesies verspreidingsmodelle van naaldekokers geskep in ‘n El Nino-geneigde biodiversiteits ‘hotspot’ in Suid Afrika, en het veranderinge in spesies rykheid, geografiese verspreiding en habitatsgeskiktheid voorspel, veertig en tagtig jaar van nou af. Volgens die modelresultate van twee verskillende emissie scenarios, sal ten minste drie spesies verlore gaan uit die area teen 2050, en vier teen 2080. Daar word voorspel dat die oorblywende spesies sal voortduur in verkleinde geografiese areas, by groter hoogte bo seespieël. Die meeste spesies hier verteenwoordig floreer in kunsmatige omgewings, soos mensgemaakte damme. Dit is dus onwaarskynlik dat ‘n verlies in konnektiwiteit ‘n rol sal speel vir hierdie spesies.

Distributed hydrologic modeling under the changing climate and environment is hampered by the difficulties in the representation of small scale variability. Identifying and understanding the links between spatial patterns of hydrologic processes at various scales may shed light on the search for simpler and yet effective representations of variability. The main objective of this thesis is to gain useful insight for the spatial aggregation of hydrologic processes by analyzing hydrologic systems at multiple spatial scales and conducting diagnostic simulations across scales. We first identified patterns of hydrologic processes by 1) comparing the surface runoff hydrographs (area-averaged discharges) from 12 hillslopes (0.5˜3 ha) with spatial proximity in agricultural land in Iowa over 72 runoff events; and 2) analyzing˜1000 recession curves observed in the nested Iowa and Cedar River basins (7~17000km2) over the period of 1988-2012 using consistent methods. We then used recession as an example to run diagnostic simulations in the Cedar River basins to reproduce the observed spatial patterns of hydrologic responses. The success allows us to decipher the link between the spatial pattern of processes at the small scale and that at larger scales. Results from this thesis demonstrate the usefulness of the "multiscale-analysis" approach and show that accounting for both the organization and randomness of the processes variability at the small scale can shape the hydrologic response at larger scales.

The goal of this study is to assess ARDBSN model performance across watershed sizes, and to assess the effect of using different mapset resolutions and basin configurations on runoff volume. Arid basin (ARDBSN) (Lane, 1982) is a distributed parameter, continuous hydrologic simulation model designed to simulate the effects of land-use practices on runoff volume, soil erosion and sediment yield on rangeland watersheds. Four subwatersheds located within the Walnut Gulch Experimental Watershed, were used in this study. Subwatershed areas ranged from 1.4 to 630 hectares. A large-scale GIS database (1:5000) developed for the Walnut Gulch Experimental Watershed, and one of the most common mapset scales (1:24 000) used in GIS analysis, were used to parameterize the ARDBSN model. Four thresholds were used to discretize watershed ST-223 and WS-11. These thresholds correspond to 1.5, 2.5, 5, and 10 percent of the watershed area. Sensitivity analysis showed that Curve Number (CN) parameter was the most important in defining runoff volume and peak runoff rate. Model calibration performance was measured primarily by the coefficient of efficiency (R², Nash and Sutcliff, 1970) for total annual runoff volume and for maximum annual peak runoff rate. Runoff volumes model efficiencies obtained were very good for LH-101, LH-103, and WS-11, and reasonably good for ST-223. In general, this model trends to over predict runoff volume for small rainfall events, and under predict for large rainfall events. The number of overland flow elements delineated within the 1:24,000 and 1:5,000 scales scarcely varies. The number of channels diminishes as the threshold values decreases. Map scale has a strong effect on the length of the channel network. Overall, high resolution maps show a better runoff volume model efficiency. Watershed 11 and watershed 223 had an average model efficiency seven and six percent higher than those obtained by these subwatersheds under the 1:24,000 map scale. Considering this, the author concludes that 1:24,000 map scale can be used with high confidence in hydrologic simulation modeling in areas with similar characteristics to those of the Walnut Gulch Experimental Watershed. The results showed that watershed configuration complexity significantly alters the model results on large watersheds, and can be attributed to the improved representation of spatially distributed watershed features with increased geometric complexity.

For decades scientists believed that herbivory had minimal impact on freshwater ecosystems. We now know that herbivory in freshwater systems equals or exceeds herbivory in terrestrial and marine systems. In extreme cases, herbivores can change clear, macrophyte dominated ecosystems into turbid plankton dominated ecosystems. Even though research on plant-herbivore interactions in freshwater systems has increased, there is still much that is unknown. This thesis is comprised of four studies investigating freshwater plant-herbivore interactions across multiple spatial scales. The first study investigated how induced chemical defenses in Cabomba caroliniana suppress herbivore consumption and growth as well as how this herbivore-generated change in plant chemistry affects the growth of plant associated microbes. At the spatial scale of individual ponds or lakes, consumers that induce their host plants may also be indirectly affecting other consumers and microbial pathogens via changes in this shared resource. The second study moves to an ecosystem scale and investigates how exotic versus native apple snails may impact Everglades' habitats. We investigated plant preference, consumption, growth and conversion efficiencies in the singly native apple snail to occur in the U.S. (Pomacea paludosa) versus four introduced species (P. canaliculata, P. insularum, P. haustrum and P. diffusa). We found that even though plant preferences are similar, invasive snails tend to eat more, grow more rapidly, and sometimes more efficiently than natives. This suggests that invasive species could have a large impact on the environment, especially the abundance of submerged plants. The third study investigated how palatability of freshwater plants varies with latitude (i.e. geographic scale). Increased herbivory at lower latitudes is hypothesized to select for increased plant defenses, which has been shown to be true for tropical forests, salt marshes, and seaweeds. When we contrasted eight confamilial plants collected in Indiana versus Southern Florida, three of four herbivores significantly preferred northern plants. When we evaluated a second set of plants collected from Indiana versus Central Florida, only one of three herbivores preferred the northern plants. Overall, our results suggest a preference for northern plants, but the strength of this relationship was variable. We hypothesize that this variability may be driven by 1) local variance in herbivore pressure that creates variance in plant defenses, and/or 2) the effect of winter length on the survival and feeding rate of herbivores. The final study expanded to a world scale, and investigated herbivore preference for native vs exotic plants. We found that both N. American crayfish and S. American snails preferred exotic plants over confamilial natives, despite responding to different plant characteristics. The single species of apple snail that occurs in N. American showed no preference for native or exotic plants from a N. American perspective, but instead exhibited preferences that correlated with its history of evolution in S. America. As the N. American species is a sister species of the S. American snails, feeding by the N. American snail appears more affected by its S. American lineage than its recent history in N. America. This suggests that phylogenetic legacy will affect choices of the herbivore as well as resistance or susceptibility of plants.

Three separate but related aspects of sediment allocation in a river/estuarine system were examined. The main purpose was to compare sediment budgets for a series of eleven nested sub-watersheds as a function of watershed size, ranging from 65 to 6900 km2. The approach quantified six budget components: upland erosion; stream bank erosion; colluvial storage; wetland storage; stream channel erosion and storage; and sediment flux at the outlets. Three budgets were developed for each sub-watershed to examine the relative proportions of budget components, budget sensitivity (the influence of individual components on the overall budget), and the uncertainty of budget components. The study area was the rural, forested, low relief York River watershed in southeastern Virginia. The relative proportions of budget components do not change with sub-watershed size. Budgets are more influenced by the tributary system than by the sub-watershed size. The budget is sensitive to most components because they are large in size and are highly variable. The uncertainties of budget components are proportional to the magnitude of the best estimates. Management efforts should focus on locally-derived sediment to improve water quality because little sediment from the upper parts of the watershed reaches the estuary. Sediment loads were needed in the sediment budgets for three estuarine sampling stations. The loads were estimated by separating the gravitational circulation, tidal pumping, and river input components of long-term total suspended solids data. The load for the station closest to the river mouth was somewhat larger than literature values. The contribution to the estuary of the two tributary stations was previously unknown. Tidal pumping, rather than gravitational circulation, is the dominant process moving suspended sediment up the estuary. The potential supply and storage of sediment in wetlands at the watershed level was examined by quantifying the areal extent of wetland type and location in the watershed, and surrounding land use, slope, and soil type. Results showed that these landscape characteristics are unevenly distributed within the York River watershed and its subdivisions. The differences in landscape characteristics between subdivisions suggest that wetland performance and its impact on water quality may vary within a watershed. Separate management approaches may be needed to accommodate these differences.

Abstract Recognition of the importance of a regional perspective for understanding the structure and dynamics of local assemblages has stimulated the emergence of the field of macroecology. Most attention has been directed to terrestrial ecosystems, while large-scale patterns in biodiversity of aquatic organisms have received less attention. In this thesis I examined patterns of aquatic diversity across several geographic areas and scales, in an effort to understand some of the environmental and spatial factors determining species diversity in aquatic environments. The main objectives of this thesis were: (i) to examine the latitudinal diversity patterns of marine crustaceans and molluscs and their relationship to large scale environmental gradients, (ii) to study macroinvertebrate species richness in headwater streams at two spatial extents, within and across drainage systems, and assess the relative importance of local, landscape and regional variables, and (iii) to study diversity patterns of macroorganisms vs microorganism, comparing distance decay patterns of stream diatoms, macroinvertebrates and bryophytes. Latitudinal diversity patterns of crustaceans and molluscs were clearly related to larval developmental mode. An increase in species richness towards high latitudes was found for species with direct development, whereas richness of species with planktotrophic development decreased poleward. Sea surface temperature was the most important environmental gradient related to species richness of both phyla and each developmental mode, but with different effects on each mode. Stream macroinvertebrate species richness at the bioregion extent was negatively related to water humic content. Another factor related to species richness at the bioregion extent was elevation range, a variable linked to stream topographic heterogeneity. Local environmental variables explained most of the variation in species richness at the drainage system extent, however high among-region variability was evident. Patterns between macro- and microorganism may not be fundamentally different, but the level of environmental control varied, being strongest for diatoms, while some groups of benthic macroinvertebrates exhibited relatively strong dispersal limitation. The relative importance of niche vs. dispersal processes is not simply a function of organism size but other traits (e.g. life-history type, dispersal capacity) may obscure this relationship.

The environmental technology industry is considered generally as a growing industry driven by urging climate-, energy- and waste problems, regulations and increasing environmental consciousness, among others. Upper Austria often referred to as an industrial region features a heterogeneous group of environmental technology firms that are outperforming other regions in Austria in terms of firm numbers and employees in this sector. Following the main theoretical approaches on cluster life cycles and cluster evolution this paper examines factors on firm and cluster level on different spatial scales that have affected the emergence and evolution of individual environmental technology enterprises and its cluster in Upper Austria. The aim of the paper is to get a profound understanding of the relevance of these factors and to evaluate their development over time. The paper uses primary data from 30 face-to-face firm interviews with managerial staff. Preliminary results suggest that factors relevant for the development of Upper Austrian environmental technology firms geographically shift and change over. Location factors that caused firms to settle in Upper Austria show a rather strong connectivity of the company founder to the region. Hence, personal factors and partners in the region are more relevant compared to other factors. At a later stage, factors such as skilled labour and networks become more important on regional level whereas other factors such as demand, regulations and public support initiatives are more relevant on national and international levels. From an evolutionary perspective factors such as demand and corporate partners become nationally and internationally more important over time, others that are mostly associated with knowledge transfer remain on the regional scale. Overall, we find tendencies of growth and geographically enlarged interaction scales of the Upper Austrian environmental technology cluster as well as a certain persistence of related ties to the regional and national innovation system. (authors' abstract)
Series: SRE - Discussion Papers

Burning fossil fuels contributes largely to the release of CO2 emissions, which CO2 accounted for 84% of the total UK greenhouse emissions in 2009. Energy production can affect climate change because it is currently produced using non- renewable fuels. As a result the UK Government has set a target of 15% renewable energy use by 2020. Renewable energy is the production of energy using fuels that are produced and sourced sustainably. Maximising renewable energy by using alternative fuels to produce our heat and electricity can help decrease our emissions and reach Government targets. The main objective of this work is to investigate the techno-economic assessment and life cycle assessment of energy from different types of biomass in the UK context. Energy use in the UK and climate change is discussed to present a case for sustainable energy. An extensive review of the thermal treatment options, as well as the different types of biomass available in the UK has been presented. Issues related to energy from biomass such as food vs. fuel and land vs. fuel are also discussed. In this thesis two second generation types of biomass are individually investigated - solid recovered fuel (SRF) and forestry waste wood chips (FWWC). A techno-economic assessment was performed on small to medium scale combustion plants using SRF (50 ktpa and 100 ktpa) or FWWC (50 ktpa, 80 ktpa and 160 ktpa). These are waste forms of biomass one of which is a mixed waste source (SRF) and the other a single waste source (FWWC), of which we have a great untapped resource in the UK. Discounted cash flow analysis, internal rate of return and levelised cost for the plants are calculated. The techno-economic assessment for the SRF plants were done previously by Yassin et al., (2008) and updated in this study using new cost data, such as landfill disposal costs and the new banded ROC’s scheme. The techno-economic performance of the FWWC was devised in the same way as for the SRF plant to ensure consistency. The results showed that the small and medium scale SRF plants were technically and economically viable, whilst only the largest scale FWWC plant was economically viable. A sensitivity analysis on the economic assessment was also performed, to investigate changes in levelised cost when seven different parameters were changed by 10% and 30%. As a result of these investigations a life cycle assessment (LCA) was performed on the large scale plants to investigate environmental aspects of sustainability. Hot-spot analysis was conducted for both plants and landfill reference systems were investigated for the SRF plant, whilst the FWWC plant investigated the emissions associated with leaving wood in the forest. In addition, the plants were compared against fossil fuel alternatives at the same production scale. The results of the LCA showed that both types of biomass are more environmentally friendly than fossil fuel alternatives. The SRF hot-spot analysis showed that the Fairport Process releases the most CO2. The FWWC hot-spot analysis showed harvesting released most CO2. The work was developed further by investigating a first generation liquid form of biomass rapeseed oil (RSO) for the production of energy using internal combustion engines. RSO is grown in increasing amounts in the UK for bio-diesel production but can also be used crude to produce energy. A techno-economic assessment of energy from RSO was conducted at small (27 ktpa) to medium (40 ktpa) scale plants, using the identical methodology as above. The results found only the medium scale plant to be economically viable. A sensitivity analysis on the economic assessment was also performed using the same percentage changes as above. An LCA was performed for the 40 ktpa RSO plant. A base case was investigated and compared to the plant. A hot-spot analysis was investigated, which showed the harvesting and cultivating units released the most CO2. The effects of growing rapeseed oil and how we use our land is investigated. The results showed the plant releases least emissions when the rapeseed is grown on rotation, using reduced tillage methodology.

Freshwater bodies such as lakes release the greenhouse gas methane (CH4) into the atmosphere. Global emissions from lakes are estimated to emit more CH4 than oceans, despite that lakes occupies a much smaller global land area. Lakes are therefore significant components for global budgets of CH4. Accurate global estimations of lakes are troublesome, partly because of the spatial and temporal variability of CH4 fluxes, making regional and global assessments filled with uncertainties. Yet, few studies consider the spatial and temporal variability of CH4 fluxes. Therefore, this study investigates the spatial and temporal variability of CH4 fluxes in lakes at different scales. Measurements were made during two field campaigns in lake Venasjön and Parsen, located in the municipality of Söderköping, Sweden. We used the commonly used floating chamber (FC) method for CH4 flux measurements. In order to investigate the small-scale flux variability, we redeveloped the FC-method by constructing two grids consisting of seven FCs distributed approximately 1m apart from each other. One grid was placed at the shallow zone at the inflow of each lake and the other at the lakes deepest zone. By sampling the grid several times every field campaign, spatial and temporal variability of fluxes at different scales could be measured. Overall, we found a significant difference of CH4 fluxes in both lakes depending on field campaign and grid location. Our results also indicate that there is a small-scale variability of CH4 fluxes in lakes. Our hope is that these findings can illustrate the importance of investigating lake fluxes at small spatial and temporal scales.
Sjöar släpper ut växthusgasen metan (CH4) i atmosfären. Globala utsläpp från sjöar beräknas avge mer CH4 än havet, trots att sjöar har en mycket mindre global areal. Sjöar är därför viktiga komponenter för globala budgetar av CH4. Dessvärre är noggranna globala uppskattningar av sjöar svårt att göra, delvis på grund av den spatial och temporala variationen av CH4, vilket gör regionala och globala bedömningar fyllda med osäkerheter. Trots detta undersöker få studier metanflödets spatiala och temporala variabilitet. Denna studie undersöker den spatiala och temporala variabiliteten av CH4-flöden från sjöar i olika skalor. Mätningar genomfördes under två fältkampanjer i sjöarna Venasjön och Parsen som ligger i Söderköpings kommun, Sverige. För att undersöka variabiliteten i en liten skala utvecklade vi den redan använda floating chamber (FC) metoden för flödesmätningar genom att bygga två grids med sju FCs, ungefär 1m mellan varje kammare. En grid placerades vid den grunda delen vid inflödet av varje sjö och den andra vid respektive sjös djupaste del. Genom att mäta griden flera gånger varje fältkampanj kunde den spatiala och temporala variationen av flöden i olika skalor undersökas. Sammantaget fann vi signifikanta skillnader i båda sjöarnas CH4-flöden mellan fältkampanjer och grids. Våra resultat tyder också på småskaliga variationer av CH4-flöden i sjöar. Vårt hopp är att dessa resultat kan ytterligare bekräfta betydelsen av att undersöka sjöflödena i små spatiala och temporära skalor

Lipid quality was evaluated in Montastrea spp. under sediment- and heat-stressed conditions to evaluate lipid ratio as an indicator of sub-lethal stress on short time scales. The ratio of storage lipid (wax ester + triacylglyceride) to structural lipid (sterol esters + phospholipid) decreased significantly (0.25 to 0.14, p < 0.01) after experimental sedimentation. FAME analysis of colonies exposed to experimental sedimentation showed a reduction of the algal, 18:3(n-6) and 18:4(n-3), polyunsaturated fatty acid (PUFA) in the polar lipid fraction. This loss of PUFA suggests a loss of algal membrane in sediment-stressed colonies. Lipid quality was similarly measured in M. faveolata over a 10-day period. Mean (n = 20) ratio of storage to structural lipid in M. faveolata dropped from 2.43 to a level of 0.98 immediately following a natural sedimentation event before recovering to levels of 1.4 and 2.9 on post-storm days 2 and 4, respectively. Colonies of M. annularis subject to heat-stress (35??C) exhibited no significant change in storage lipid ratio, while levels of Free Fatty Acids increased significantly from 0.012 (n = 22) to 0.156 mg lipid/g dry tissue (n = 22)(p < 0.05). FAME analysis of tissue lipids extracted from the heat-stressed colonies showed changes in the polar fraction, with significant decreases in the 18:3(n-6), 18:3(n-3), 18:4(n-3), 20:4(n-6) and 20:5(n-3) (p < 0.05) PUFA and subsequent significant increases in the saturated fatty acids, 16:0 and 18:0 (p < 0.05). These changes in lipid quantity and quality indicate possible oxidation and preferential digestion of zooxanthellar membranes. Stress experiments were repeated in M. annularis using VacutainerRTM blood collection tubes to collect micro-tissue samples without destroying skeleton of the sample colonies. A significant decrease in storage: structural lipid ratio after sedimentation was also detected using the micro-tissue technique. This study indicates that the relative abundance of lipid subclass components can indicate sub-lethal environmental stress, on short time scales, in M. annularis and M. faveolata. Furthermore, micro-tissue collection techniques permit repeated monitoring coral colonies to assess the manifestation of stress from first detection of impact at the cellular level to changes in community to changes in community structure detectable over longer time scales.

Ecosystem management is positioned as the modern paradigm of resource management. Fire management activities within the natural resource management agencies, under the adoption of an ecosystem management approach, supports an increased focus upon prescribed and manager-ignited fire programs. A review of past national fire policies and the effects they have had upon ecosystem conditions today further supports the role for prescribed fire. Under an ecosystem management approach, resource managers need to consider the effects of fire management activities over longer temporal and broader spatial scales. Examining the ecological, social, political, and economic aspects surrounding fire management activities on these scales will help ensure healthier ecosystems in perpetuity. Although the suppression of wildfires will remain a necessary component to fire management activities today, there needs to be an increased effort to reintroduce fire into ecosystems and to recognize fire as a natural component vital to maintaining ecosystem health.

Space-borne remote sensing datasets have the potential to allow us to progress towards global scale flood prediction systems. However, these datasets are limited in terms of space-time resolution and accuracy, and the best use of such data requires understanding how uncertainties propagate through hydrological models. An unbiased investigation of different datasets for hydrological modeling requires a parsimonious calibration-free model, since calibration masks uncertainties in the data and model structure. This study, which addresses these issues, consists of two parts: 1) the development and validation of a multi-scale distributed hydrological model whose parameters can be directly linked to physical properties of the watershed, thereby avoiding the need of calibration, and 2) application of the model to demonstrate how data uncertainties propagate through the model and affect flood simulation across scales. I based the model development on an interactive approach for model building. I systematically added processes and evaluated their effects on flood prediction across multiple scales. To avoid the need for parameter calibration, the level of complexity in representing physical processes was limited by data availability. I applied the model to simulate flows for the Cedar River, Iowa River and Turkey River basins, located in Iowa. I chose this region because it is rich in high quality hydrological information that can be used to validate the model. Moreover, the area is frequently flooded and was the center of an extreme flood event during the summer of 2008. I demonstrated the model's skills by simulating medium to high-flow conditions; however the model's performance is relatively poor for dry (low flow) conditions. Poor model performance during low flows is attributed to highly nonlinear dynamics of soil and evapotranspiration not incorporated in the model. I applied the hydrological model to investigate the predictability skills of satellite-based datasets and to investigate the model's sensibility to certain hydro-meteorological variables such as initial soil moisture and bias in evapotranspiration. River network structure and rainfall are the main components shaping floods, and both variables are monitored from space. I evaluated different DEM sources and resolution DEMs as well as the effect of pruning small order channels to systematically decreasing drainage density. Results showed that pruning the network has a greater effect on simulated peak flow than the DEM resolution or source, which reveals the importance of correctly representing the river network. Errors on flood prediction depend on basin scale and rainfall intensity and decrease as the basin scale and rainfall intensity increases. In the case of precipitation, I showed that simulated peak flow uncertainties caused by random errors, correlated or not in space, and by coarse space-time data resolution are scale-dependent and that errors in hydrographs decrease as basin scale increases. This feature is significant because it reveals that there is a scale for which less accurate information can still be used to predict floods. However, the analyses of the real datasets reveal the existence of other types of error, such as major overall bias in total volumes and the failure to detect significant rainfall events that are critical for flood prediction.

In recent decades, extreme meteorological events have become more frequent and more severe. Flooding, heavy precipitation and droughts, in particular, are a few of these extreme events that can cause widespread property damage and loss of life. The climate is always changing and there is a general agreement that the changes will be more amplified and occur more rapidly due to anthropogenic influences. As a result, it is expected that the societal and economic impacts of heavy precipitation, floods, and droughts will increase as the climate continues to rapidly change. For these reasons, continued research to improve extreme precipitation predictions and long-term projections is vital. With improved projections, society will be able to improve their efforts to prepare for and implement better management practices to effectively adapt to the changing climate and help reduce the impacts of a changing climate. A great deal of progress has already been made in extreme precipitation research in relation to climate change. Overall, the tendency for dry areas to get drier and wet areas to get wetter has been identified. However, much of the work has focused on the daily timescale, and much less is known about sub-daily precipitation. It is becoming increasingly more important to consider this time scale because of evidence that climate change could have more of an impact on sub-daily (e.g., 3-hourly) rather than daily precipitation. To complicate the matter, there is still a need to evaluate the performance of global climate models in reproducing the precipitation statistics at the sub-daily time scales. The goal of this work is to evaluate the projected changes in precipitation at both the daily and sub-daily time scales and, more specifically, understand whether daily or sub-daily precipitation extremes will change more through the end of this century. However, to understand future projections it is first vital to analyze model accuracy and determine how well global climate models can reproduce the extreme precipitation statistics across the historical past. This is accomplished by comparing the historical runs for each model to observations during the same time period using several different methods, including a skill score analysis, using Taylor diagrams to visualize accuracy, and meridional plots that show intermodel variability. The results from this analysis show model performance for daily extreme precipitation is higher than that of the 3-hourly extreme precipitation. Although there are few models that do an adequate job of producing reliable results at the sub-daily time scale, there is an overall significant increase in skill as the temporal resolution becomes coarser. Variability also exists among models, with sub-daily precipitation having more widespread variability across every latitude, but daily precipitation has a wider range in potential extreme precipitation that is focused more in the tropics. Model performance also varies by season, resulting in higher performance and less variability among models for individual seasons. These results also point to several models that consistently perform well for both sub-daily and daily extreme precipitation, but it is still worth remembering that there is no guarantee that a good performance during the historical period ensures a good performance in the futures as well. The next part of the work focuses on the models with the highest performance in reproducing the observations. From there, it was possible to determine locations with the greatest changes in precipitation, the magnitude of changes, and whether sub-daily or daily extreme precipitation will be impacted more by climate change. Overall, extreme precipitation at both sub-daily and daily times scales is projected to increase globally. At the regional scale, precipitation is projected to primarily increase in the tropics, with smaller changes towards the poles. Areas of decreases in precipitation vary by model with the exception of a decrease in precipitation near the tropical Pacific Ocean that is seen in almost every model.

América Latina es actualmente una de las fronteras mineras más atractivas del mundo, que concentra un tercio de las inversiones mundiales del sector. Sin embargo, mientras la presión por extraer metales aumenta, la región está viviendo una ola de movilizaciones sociales opuesta a la expansión de las actividades mineras a gran escala. Mientras las comunidades denuncian que las actividades mineras ponen en riesgo sus formas de sustento, desprecian sus derechos y su futuro, los gobiernos nacionales y las compañías mineras promueven la actividad como una fuente de desarrollo y bienestar social. Las críticas son vistas como motivadas por intereses políticos o desinformación. Desde un marco de ecología política, nutrido por estudios sobre la política de las escalas, la tesis estudia los movimientos de justicia ambiental que se oponen a las actividades mineras metalíferas de gran escala en América Latina. A tal efecto, recurre a dos aproximaciones diferentes. En una primera aproximación, la tesis analiza cómo y por qué los movimientos de justicia ambiental se forman, sus discursos, sus demandas y sus estrategias y el modo como estos movimientos se involucran en luchas por las escalas disputando su jerarquía y reivindicando el poder de las comunidades locales para decidir sobre los proyectos mineros. Se utilizaron métodos de investigación acción para realizar un estudio de caso del conflicto minero aurífero de Esquel (2001-2003, Argentina), donde se detuvo el proyecto tras un referéndum local. Adicionalmente, fuentes primarias y secundarias fueron utilizadas en un estudio de casos múltiples para analizar la emergencia y el despliegue de casos de consultas/referendo comunitarias sobre minería a gran escala en América Latina. En esta investigación, realizada con Leire Urkidi, estudiamos 68 casos de consultas locales ocurridas entre los años 2002 y 2012 en Peru, Guatemala, Argentina, Colombia y Ecuador. Alrededor de 700.000 personas participaron en estas consultas, expresando un rechazo masivo a las actividades mineras en la región. Se concluyó que las comunidades reclamaban el reconocimiento de sus miradas locales sobre el desarrollo que no eran compatibles con los impactos, riesgos e incertidumbres de la minería a gran escala. Los conflictos se exacerbaban porque los procedimientos de toma de decisiones no permitían incorporar adecuadamente las perspectivas locales sobre los aspectos técnicos y no técnicos que estaban en juego. Analizando la propagación de las consultas, sostenemos que se trata de una institución híbrida, multi-escalar, que simultáneamente construye una nueva escala de regulación (toma de decisiones) consistente en la participación local a través del referendo/consulta. Las consultas surgen como una respuesta de democracia local frente a las injusticias ambientales en contextos de represión y criminalización a activistas que ganan legitimidad en la medida que ofrecen espacios de participación a las comunidades afectadas. Son instituciones híbridas porque son promovidas por alianzas entre movimientos sociales y gobiernos locales que recuperan y resignifican derechos y leyes indígenas y de participación municipales, nacionales e internacionales. Así, las consultas no sólo desafían las escalas de significado hegemónicas que gobiernan a las actividades mineras sino, además, reconstruyen y ponen en práctica una nueva escala de regulación. En una segunda aproximación, en colaboración con Sara Latorre y el apoyo de Giuseppe Munda y Carlos Larrea, se aplicaron técnicas de evaluación social multi-criterio y de construcción de escenarios para estructurar las implicancias multi-dimensionales de desarrollar actividades extractivas en áreas social y ambientalmente sensibles. En el capítulo dedicado al conflicto minero de Íntag (Ecuador), sostenemos que esta aproximación permite hacer visibles escalas, valores sociales e incertidumbres que son opacados por los discursos que hegemonizan el debate minero, enfocados casi exclusivamente en los resultados económicos a nivel nacional.
Latin America is currently one of the most attractive mining frontiers in the World, concentrating one third of global mining investments. However, as the pressure to extract ores grows, the region witnesses a wave of social mobilizations against the expansion of large-scale metal-mining activities. While communities claim that mining activities endanger their livelihoods, and despise their rights and their future, national governments and companies promote this activity as a source of development and wellbeing. Complaints are framed as being politically motivated or based on misinformation. From a political ecology framework, nurtured by politics of scale studies, this thesis studies environmental justice movements contesting large-scale metal-mining activities in Latin America and their struggles over scales. Two different approaches are developed. In a first approach, the thesis addresses how and why environmental justice movements have formed, which are their discourses, their claims and strategies and how these movements engage in struggles over scales, contesting scalar hierarchies and reclaiming communities' power to decide on mining projects. Action research methods were used to conduct an in-depth case study in Esquel gold mining conflict (2001-2003, Argentina) where a project was stopped by a local referendum. Moreover, primary and secondary sources were used to conduct a multiple case study analysis of the emergence and spread of other community consultations/referenda on large-scale mining activities in Latin America. In this research, conducted with Leire Urkidi, we studied the 68 cases of community consultations/referenda that took place between 2002 and 2012 in Peru, Guatemala, Argentina, Colombia and Ecuador. About 700.000 people participated in these consultations, expressing a massive rejection to mining activities. I conclude that communities are demanding recognition for local views on development that are not compatible with large-scale mining, given its impacts, risks and uncertainties. Conflicts are exacerbated by the fact that mining decision-making procedures cannot adequately accommodate local views regarding technical and non-technical issues at stake. Analysing the spread of consultations I claim that they are a multi-scalar institution that constructs a new scale of regulation (decision-making): local participation via referendum/consultation. Consultations emerge as a local democratic response to environmental injustices in contexts of repression and criminalization of activists, and gain legitimacy as they become spaces of participation for affected populations. Consultations are moreover a hybrid institution, promoted by alliances between social movements and local governments that reclaim and re-signify municipal, national and international participation and indigenous rights and legislations. In this vein, consultations not only challenge hegemonic scales of meaning governing mining activities but re-construct and put in practice a new scale of regulation. In a second approach, in collaboration with Sara Latorre and with the support of Carlos Larrea and Giuseppe Munda, social multi-criteria evaluation and scenario techniques were applied to structure the multi-dimensional implications of developing extractive activities in socially and environmentally sensitive locations. In this chapter on the Íntag mining conflict (Ecuador), I claim that this approach is able to make visible scales, social values and uncertainties that are made invisible by hegemonic discourses in the mining debate that focus almost exclusively on economic results at national level.

This dissertation addresses the need to define potential impacts of recent and proposed changes in federal wetland regulation in a quantifiable manner. Consideration was made not only of total wetland acreage and wetland types that could sustain losses, but also to categorize the effect such losses would have in terms of wetland functions, at the watershed scale. This work took a Geographic Information Systems (GIS) approach, and included employing a best-professional judgment model for scoring habitat, water quality and flood attenuation functions to determine potential cumulative impacts; a water quality study which related wetland and watershed variables to nutrient and sediment loads; and an amphibian metapopulation model to determine the effects of loss of landscape connectivity resulting from wetland management decisions. The study area encompassed several watersheds in Southern Virginia, USA. Results from best professional judgment model show that despite a decrease over the years in acreage receiving reduced regulatory protection, the functional caliber of wetlands afforded the least protection is actually higher with each new implementation of regulatory criteria. These results, and the results of similar models, updated as more information and data sets become available, should be a valuable tool for both regulators and managers at local, as well as regional and The water quality model reduced 41 wetland and watershed variables to 5 principal components, which were then used in regression equations to relate the variables to nutrient and sediment loads. Although differing variables played roles in different water quality components, the overriding factor affecting improved water quality related to the proportion of vegetated area found within a 100 meters of stream courses, with negative water quality related to the proportion of developed to vegetated areas within the 100 meter buffer. Results from the amphibian habitat model highlight the importance of the pattern of wetlands across the landscape. Removal of wetlands smaller than 0.5 acres had a greater influence on occupancy rates in all wetlands, presumably due to their position providing between wetland connectivity. Policy and management decisions should be altered to consider each of these conclusions if functional conservation is to be achieved.

Analysis of soil-derived DNA has been shown to minimize problems seen during traditional vegetation surveys, e.g. by matching the eDNA to a reference database for taxonomic identification rather than relying solely on taxonomic expertise. However, it has been debated to what extent and how accurately eDNA acts as a proxy for biodiversity. The reliability on eDNA and the awareness on influencing factors is also important for palaeoenvironmental reconstructions where above-ground vegetation cannot be used. This study aimed to investigate how well modern soil-derived eDNA reflects the contemporary vascular vegetation communities in a subarctic environment, and if the efficiency of the taxonomic identification differed between spatial scales. Near-surface soil samples at altitudinal gradients along numerous transects were collected in combination with vegetation surveys. The eDNA was amplified through metabarcoding using the P6 loop region of the chloroplast trnL intron, followed by a high-throughput sequencing. No difference in the number of identified taxa between eDNA and vegetation survey was seen at landscape scale. In contrast, the number of identified taxa was consistently higher in the vegetation survey at smaller spatial scales. The efficiency of identified taxa per scale remained stable for the vegetation survey, whereas for eDNA, a decreasing trend was seen. This study highlights the variations on taxa identification between both methods and which factors might cause it. Combining the methods allows for a more precise modern biodiversity estimation, as well as to minimize wrongful conclusions. This allows for a more accurate palaeoenvironmental reconstructions, which in turn can improve future species conservation decisions.

Orientador: Lilian Casatti
Coorientador: Marcus V. Cianciaruso
Coorientador: Silvio F. B. Ferraz
Banca: Janne Soininen
Banca: Leandro Duarte
Banca: Rafael Leitão
Banca: Tadeu Siqueira
Resumo: Contexto. Em riachos neotropicais, poucos estudos têm considerado os efeitos de variáveis ambientais em diferentes escalas espaciais sobre a ictiofauna. Além disso, estudos relacionados com a escala em sua maioria incorporam uma única faceta e um único componente da biodiversidade, proporcionando uma visão incompleta da estrutura da comunidade de peixes. Objetivo. Determinar a contribuição relativa de características locais, de microbacia e dos padrões espaciais na explicação da variação dos componentes α e β das facetas taxonômica, funcional e filogenética de peixes de riachos. Métodos. Foram amostrados 85 trechos de riachos (= 85 microbacias) no Alto Rio Paraná, Brasil. Diversas análises estatísticas foram utilizadas para explicar as facetas e componentes da biodiversidade em função de variáveis locais, de microbacia e espaciais. Resultados. Para quase todas as facetas e seus componentes α e β, os fatores ambientais locais explicaram uma fração substancial da variância. As variáveis na escala de microbacia, de um modo inesperado, e a estruturação espacial, como esperado, contribuíram pouco para a variação da biodiversidade ou não foram significativas. Conclusões. Este estudo tem implicações claras para a proteção da biodiversidade íctica regional e poderiam ser integradas na gestão de riachos de diferentes maneiras. Primeiro, os resultados destacam a importância de fatores ambientais locais para a manutenção da biodiversidade de peixes de riachos situados em paisagens agrícolas. Por conseguinte, essas características ambientais chave devem ser restauradas ou, pelo menos, preservadas. Segundo, uma vez que funções e processos ecossistêmicos exercidos pela zona ripária foram ou estão sendo perdidas, ações voltadas para a restauração das matas ciliares na rede de drenagem devem ser uma prioridade nas bacias estudadas. Terceiro, já que as espécies raras que são funcionalmente e/ou...
Abstract: Context. In Neotropical streams, very few studies have considered the effects of environmental variables at different spatial scales on fish communities. Furthermore, scale-related studies mostly include only one facet and one component of biodiversity providing an incomplete picture of fish community structure. Objective. To determine the relative contributions of catchment and local environmental features and spatial patterns in explaining variation in the α- and β-components of taxonomic, functional and phylogenetic diversity facets of stream fish. Methods. Fish sampling was performed in 85 stream reaches (= 85 catchments) in the Alto Rio Paraná, Brazil. Different statistical analyzes were performed to explain the facets and components of biodiversity as a function of local, catchment or spatial variables. Results. For almost all facets and its α- and β-components, local environmental factors explained a substantial fraction of variance. Catchment variables, in an unexpected way, and spatial structuring, as expected, contributed little to the variation in the biodiversity or were not significant at all. Conclusions. This study has clear implications for protection of regional stream fish biodiversity and would be integrated into stream management in different ways. First, the results highlight the importance of local environmental factors for maintaining stream fish biodiversity in agricultural landscapes. Therefore, these key environmental features must be restored, or at least preserved. Second, because ecosystem functions and processes provided by riparian zone were or are being lost, actions directed toward restoring riparian forest in the drainage network should be a priority in the studied basins. Third, because rare species that are functionally and/or phylogenetically 'unique' possibly contributed disproportionately to the functional/phylogenetic dissimilarity among sites this group of species deserve special ...
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Pervasive growth in industrialization and advances in technology now exposes much of the world to anthropogenic night light and noise (ANLN), which pose a global environmental challenge in terrestrial environments. An estimated one-tenth of the planet’s land area experiences artificial light at night — and that rises to 23% if skyglow is included. Moreover, anthropogenic noise is associated with urban development and transportation networks, as the ecological impact of roads alone is estimated to affect one-fifth of the total land cover of the United States and is increasing in space and intensity. Existing research involving impacts of light or noise has primarily focused on a single sensory stressor and single species; yet, little information is known about how different sources of sensory stressors impact the relationships within tightly-knit and complex systems, such as within plant-pollinator communities. Furthermore, ANLN often co-occur, yet little is known about how co-exposure to these stressors influences wildlife, nor the extent and scale of how these stressors impact ecological processes and patterns. In Chapter 1, we had two aims: to investigate species-specific responses to artificial night light, anthropogenic noise, and the interaction between the two by using spatially-explicit models to model changes in abundance of 140 of the most prevalent overwintering bird species across North America, and to identify functional traits and contexts that explain variation in species-specific responses to ANLN stressors with phylogenetically-informed models. We found species that responded to noise exposure generally decreased in abundance, and the interaction with light resulted in negative synergistic responses that exacerbated the negative influence of noise among many species. Moreover, the interaction revealed negative emergent responses of species that only reacted when both ANLN were presented in combination. The functional trait that was the most indicative of avian response to ANLN was habitat preference. Specifically, species that occupy closed habitat were less tolerant of both sensory stressors compared to those that occupy open habitat. Species-specific responses to ANLN are context-dependent; thus, knowing the information that regulates when, where, how, and why sensory pollutants influence species will help management efforts effectively mitigate these anthropogenic stressors on the natural environment. In Chapter 2, using field-placed light manipulations at sites exposed to a gradient of skyglow, we investigated the influence of direct and indirect light on the yucca-yucca moth mutualism by quantifying chaparral yucca (Hesperoyucca whipplei) fruit set and the obligate moth (Tegeticula maculata maculata) larval density per fruit. Although many diurnal insects are thought to exhibit minimal phototaxis, we show that direct light attracted adult moths and incited higher pollination activity, resulting in an increase in fruit set. However, larval recruitment decreased with elevated light exposure and the effect was strongest for plants exposed to light levels exceeding natural moonlit conditions (> 0.5 lux). Contrarily, increases in ambient skyglow resulted in an increase in both fruit set and larva counts. Our results suggest that plant-pollinator communities may respond in complicated ways to different sources of light, such that novel selection pressures of direct and indirect light have the potential to benefit or disrupt networks within complex diurnal plant-pollinator communities, and ultimately alter the biodiversity reliant on these systems. By analyzing pervasive stressors across a continental-wide scale, we revealed considerable heterogeneity in avian responses to light and noise alone, as well as the interaction between them. Based on overall responses to the interaction between light v and noise, we suggest management efforts should focus on ameliorating excessive noise for overwintering bird species, which should decrease the impact from synergistic responses, as well as the negative impact from noise alone. There is still much to learn about responses to these stressors and smaller-scale studies should take our approach of systematically assessing interaction responses to ANLN. Moreover, our small-scale study revealed both local sources of direct light and skyglow impact the recruitment for both yucca moths and their reciprocal plant hosts. However, it is still unknown if or why other diurnal pollinators experience positive phototaxis, and whether direct lighting influences the physiology, behavior, or multiple factors relating to reproduction and fitness. Correspondingly, it is unknown if the novel selection pressures of direct and indirect light are disrupting complex diurnal plant-pollinator communities. Future research on artificial night light will need to investigate the intricate responses of diurnal pollinators to both direct and indirect light that will identify concrete mechanisms relating to physiological or behavioral susceptibility and inform predictions on how wide-spread communities will shift with this global driver of emerging change.

Geochemical mapping is a valuable tool for the control of territory that can be used not only in the identification of mineral resources and geological, agricultural and forestry studies but also in the monitoring of natural resources by giving solutions to environmental and economic problems. Stream sediments are widely used in the sampling campaigns carried out by the world's governments and research groups for their characteristics of broad representativeness of rocks and soils, for ease of sampling and for the possibility to conduct very detailed sampling In this context, the environmental role of stream sediments provides a good basis for the implementation of environmental management measures, in fact the composition of river sediments is an important factor in understanding the complex dynamics that develop within catchment basins therefore they represent a critical environmental compartment: they can persistently incorporate pollutants after a process of contamination and release into the biosphere if the environmental conditions change. It is essential to determine whether the concentrations of certain elements, in particular heavy metals, can be the result of natural erosion of rocks containing high concentrations of specific elements or are generated as residues of human activities related to a certain study area. This PhD thesis aims to extract from an extensive database on stream sediments of the Romagna rivers the widest spectrum of informations. The study involved low and high order stream in the mountain and hilly area, but also the sediments of the floodplain area, where intensive agriculture is active. The geochemical signals recorded by the stream sediments will be interpreted in order to reconstruct the natural variability related to bedrock and soil contribution, the effects of the river dynamics, the anomalous sites, and with the calculation of background values be able to evaluate their level of degradation and predict the environmental risk.

The main objective of this research was to develop and utilize a coupled surface water groundwater model to simulate hydrological responses of watersheds. This was achieved by coupling the U.S. Geological Survey (USGS) groundwater flow model, MODFLOW, and the rainfall runoff model, TOPMODEL, in one case study and coupling MODFLOW with a networked version of TOPMODEL called TOPNET in another case study. The model coupling was achieved using the InCouple approach, which utilizes Potential Coupling Interfaces (PCIs) that are abstractions from model flow diagrams that expose only those aspects of a model relevant to coupling. Coupling the rainfall-runoff models to MODFLOW involved development of a routine relating the spatial discretization of MODFLOW to TOPMODEL and similarly MODFLOW to TOPNET and development of a feedback scheme where groundwater and surface water interact in the soil zone. The key coupling concept was replacing the wetness index-based depth-to-water table concept of TOPMODEL with the groundwater heads simulated by MODFLOW. In the MODFLOW-TOPMODEL coupling, using data for the Tenmile Creek watershed, for the period, 1968 to 1972, it was concluded that the coupled model was able to continuously simulate the stream flow. However, the coupled model under predicted stream flow and did not agree well with observations in a point wise comparison. A mean coefficient of efficiency of 0.54 was obtained between simulated and measured stream flow. Only 24% of received precipitation was observed as baseflow and this shows that there is limited interaction between surface water and groundwater in the watershed. It was demonstrated using the coupled model that the lateral flow processes and the interactions between groundwater and surface water have a major importance for the water balance. For the Big Darby watershed, for the period 1992 to 2000, the coupled model adequately predicts the stream and groundwater flow distribution in the watershed. After model calibration, simulated groundwater showed the greatest residual variance, attributed to model error and uncertainty in model parameters. Model fit efficiencies of 0.61 and 0.69 were obtained for simulating stream flow measured at two gaging stations. The overall watershed hydrologic budget also showed small mass balance errors using the coupled model. However, the study also shows the need for further research in regard to constraining the groundwater recharge parameter which links the models.