Browsing by Subject "Biodiversity"
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Item Biogeography of upland bird communities in the Peruvian Amazon(2009-12) Pomara, Lazarus Yates; Young, Kenneth R.; Barth, Robert H.; Dull, Robert A.; Miller, Jennifer A.; Ruokolainen, KalleThe western Amazon is known to be one of the most biologically diverse regions in the world, yet information about the spatial distribution of that biodiversity and the processes governing its distribution remains scarce. An improved understanding of those biogeographic patterns and processes can inform conservation and development planning in areas where anthropogenic landscape change is ongoing. Spatial components of biodiversity are known to be influenced by historical and present-day physical and human geographic processes. There is evidence that major Amazonian rivers form the boundaries of biological regions, at least for birds. Other factors that may influence bird species composition include the dispersal limitations of individual species, forest plant species composition and structure, topography, forest fragmentation, and hunting. Sites where bird species composition was measured in this study represented mature, upland forest on both sides of the Amazon River, and a range of non-flooded forest types, as indicated by soil and plant surveys. Bird species compositional variation was closely correlated with variation in plant species composition, human disturbance associated with forest fragmentation, and position north or south of the Amazon River. The strongest differences were between opposite sides of the river, even though local environments, including plant composition, were not different on the two sides. This strongly suggests that historical biogeographic factors, rather than present-day environmental gradients, are responsible for bioregional boundaries at Amazonian rivers. The difference between plant and bird distributions at this scale underscores the pressing need to re-evaluate general notions of bioregional complexity and pattern in the Amazon basin. Locally, the influence of habitat fragmentation on animal communities, including reduced species richness, was confirmed. The influence of local floristic variation is of particular importance due to its ubiquity across western Amazonia. Thus, understanding the distributions of soils and vegetation is critical for explaining Amazonian animal diversity. The use of these factors to model bird community heterogeneity contradicts assumptions that the processes shaping Amazonian animal community diversity are too complex to measure efficiently, and their use contributes a new understanding of the dimensions of that diversity.Item Connecting backyard wildlife habitats in Austin, TX : case study of Wildlife Austin(2009-12) Koone, Emily Anna; Dooling, SarahUrbanization is considered one of the leading threats to biodiversity and wildlife habitat (McKinney 2002; Shochat et al. 2006). Urban environments are humandominated systems, yet they support wildlife habitat and provide meaningful ecological functions. Methods to conserve biodiversity and minimize habitat loss and fragmentation in urban environments include utilizing private residential yards and gardens to enhance habitat connectivity. Private residential yards or gardens designed to attract and support wildlife are known as backyard habitats and wildlife gardens. The City of Austin, Texas initiated Wildlife Austin in 2007. Wildlife Austin coordinates backyard habitats in Austin as a National Wildlife Federation Community Wildlife Habitat [trademark]. My research analyzes the goals of the Wildlife Austin from the perspective of landscape ecology and urban ecology; reviews research related to backyard habitats in order to identify ways of enhancing habitat connectivity for bird communities; and provides recommendations for a more scientifically grounded approach and management in the promotion of backyard wildlife habitat.Item Consequences of habitat fragmentation: connectivity lies in the eye of the beholder(2008-05) Sardinha-Pinto, Naiara, 1979-; Keitt, Timothy H.This dissertation was motivated by the problem of pattern and scale in ecology. All chapters present models that aim at predicting species’ responses to habitat fragmentation. Chapters differ mainly in the nature of the responses being investigated: spatial variation in abundance, or dispersal. In each chapter, I illustrate how current models can be modified to incorporate species’ perception of the landscape. Three sources of bias have been examined here: interspecific variation in (i) ecological neighborhood, (ii) ecological generalization, and (iii) in the response to regional processes. I have deliberately moved away from traditional single-scale, patch-based measures of landscape connectivity. Great emphasis has been placed on the anthropogenic aspect of the landscape, and on the role of the landscape matrix. Habitat fragmentation is a common feature of most (if not all) biodiversity hotspots. I hope the tools shown here can serve as general approaches to study how species are differentially affected by habitat fragmentation, and to ultimately understand how disturbed landscapes can “filter” natural communities.Item EFFECTS OF HABITAT FRAGMENTATION ON NON-VOLANT SMALL MAMMALS OF THE INTERIOR ATLANTIC FOREST OF EASTERN PARAGUAY(2010-12) de la Sancha, Noe; Salazar-Bravo, Jorge; Strauss, Richard E.; DElia, Guillermo; McIntyre, Nancy E.; Delahunty, TinaThe goal of my dissertation research was to improve the understanding of the Atlantic Forests (AF) of South America by applying the knowledge gathered from Paraguay’s forest remnants to the rest of the AF remnants. Specifically, my aims were to increase our knowledge of the non-volant small mammals in eastern Paraguay forests; examine the relationship between species and forest remnant area; compare biodiversity between Paraguay and Brazil; and examine biodiversity patterns throughout the AF through metacommunity and latitudinal structure analyses. By examining this system I achieved the following: 1) I conducted standardized surveys for forest remnants of Paraguay at 40 localities, in 4 forest remnants; 2) I established species-area relationships for four of the major forest remnants of Paraguay; 3) I uncovered similarity relationships between different coastal and non-coastal Brazilian and Paraguayan sites; 4) I identified differences in biodiversity among different-sized forest remnants, tropical and temperate sites, and coastal and inland remnants for a variety of diversity components; 5) I categorized the metacommunity structure of the small mammal assemblages of the AF; 6) and finally, I detected latitudinal relationships between biodiversity and assemblage structures throughout the AF. In Chapter 2, I modeled richness of non-volant small mammals in remnants of AF, utilizing studies and survey information from the Brazilian AF. A three-dimensional model was built to predict number of species as functions of trapping effort and remnant size. Unlike traditional species-area models, this three-dimensional model allowed for the incorporation of different trapping efforts, plus it recovered a nonlinear species area relationship. In Chapter 3, I examined biodiversity at two scales: 1) within the forest fragments of Paraguay, comparing the various grids sampled; and 2) between forest fragments of Paraguay and Brazil. I employed a multivariate approach to examine how each component of biodiversity indices behaved as a function of scale, forest size, and locality. In Chapter 4, effects of latitude and metacommunity structure were assessed for remnants from northeastern Brazil down to eastern Paraguay. The aim was to understand how fragmentation may affect large-scale patterns of the Atlantic Forest, and in doing so, to understand how Paraguay fits into the structural framework of this system.Item Endohelminths from six rare species of turtles (Bataguridae) from Southeast Asia confiscated by international authorities in Hong Kong, China(Texas A&M University, 2004-09-30) Murray, Rebecca AnnSpecimens of 6 species of threatened, vulnerable, and endangered turtles (Cuora amboinensis, Cyclemys dentata, Heosemys grandis, Orlitia borneensis, Pyxidea mouhotii, and Siebenrockiella crassicollis) belonging to family Bataguridae, were confiscated in Hong Kong, China on 11 December 2001 by international authorities. Endohelminth studies on these turtle species are scarce, and this study provided a rare opportunity to examine a limited number of specimens for endohelminths. Ten different parasite species were collected and there were 16 new host records. This is the first record of a parasite from P. mouhotii. The parasite prevalences found in this study provide a basis for a better understanding of the phylogenetic relationships of the family Bataguridae to other families, especially Testudinidae. Based on known life cycles, parasites found provided an indication of food preferences of these 6 turtle species that support previous studies of the turtles' feeding habits. However, the results of the parasite survey from O. borneensis provided additional feeding habit information. The list of endohelminths herein is intended to provide a foundation for future parasite studies of the 6 species of Asian turtles.Item Forest diversity and conservation in the western Amazon based on tree inventory and remote sensing data(2011-12) Wang, Yung-ho Ophelia; Young, Kenneth R.; Crews, Kelley A.; Miller, Jennifer A.; Sarkar, Sahotra; Pitman, Nigel C.This dissertation contributes to debates in conservation biogeography by examining the spatial heterogeneity of local and regional tree diversity feature using ground and remotely sensed data, and by taking approaches to design a spatially explicit landscape zonation map for future conservation planning in western Amazon, one of the most biodiverse regions on Earth. Fine scale tree diversity and conservation-related studies took place in tropical rainforests in southeastern Ecuador, whereas coarse scale tree diversity research was conducted using data from eastern Ecuador and northern Peru. The lack of species assemblages within three 1-ha tree inventory plots in southeastern Ecuador and the weak correlations with biophysical environment implied that neutral processes may contribute to species diversity. In contrast, differences in species assemblages between plots corresponded to relative geographic locations of the plots, indicating that geographic distance or dispersal limitation may play an important role influencing diversity patterns at a regional scale. Species of high local abundance was found in 1-ha tree inventory plots in western Amazon. Changes in density of locally abundant species between western and eastern plots indicated that some species may have limited distributions. Shifts in species dominance and the significant relationship between floristic variation and geographic distances between plots implied dispersal limitation. Variation in rainfall showed significant relationship with species composition. Therefore, dispersal limitation and precipitation seasonality are potentially the most significant factors that contribute to spatial differences in tree diversity in western Amazon. Characteristics of canopy shadows and palm stem density based on fine-resolution aerial photographs were characterized as exploratory analyses to extract alpha and beta diversity features using remotely sensed data. A zonation map design using multispectral habitat classification and other remote sensing data performed well in its spatial arrangement when potential indigenous land use was integrated. Based on the results of analyses for conservation biogeography, this dissertation concludes that local and regional tree diversity may be influenced by dispersal limitation and seasonality, and that the application of remote sensing for biodiversity conservation is feasible in very species-rich forests.Item Functional groupings of stream fishes: Spatiotemporal variation, predictability, and patterns of diversity(2005-12) Higgins, Christopher L.; Strauss, Richard E.; Wilde, Gene R.; Schmidt, Kenneth A.; Willig, Michael R.; Winemiller, Kirk O.Biodiversity and ecosystem function is a contemporary topic at the forefront of ecology. It is driven by the fundamental need to understand how the loss of biodiversity, which is occurring all around the world, affects goods and services obtained from ecosystems. The scientific literature indicates functional attributes of species strongly influence ecosystem properties; however, a lack of understanding exists regarding the relationship among functional diversity, taxonomic diversity, and community structure. As a result, this dissertation contributes to our understanding of the relationship between biodiversity and ecosystem function by analyzing the organization of stream-fish assemblages from a functional and taxonomic perspective and by synthesizing the relationship between the two aspects of biodiversity. I used a combination of previously published data, which covered broad biogeographic areas, and my own field work to address various issues on multiple spatial and temporal scales. I focused exclusively on stream-fish assemblages because they are one of the most underrepresented groups of animals in biodiversity and ecosystem function research and because they play an important role in aquatic ecosystems by removing other plants and animals from the community, actively produce fragments or feces containing the bodies of their prey, and by mechanically disturbing substrates, thereby increasing suspension of materials in the water column. In general, I found functional redundancy within stream-fish assemblages, with functional groups dividing niche space more evenly than species whether looking at the entire state, ecoregions, river basins, or individual locations, and the spatial and temporal structure of stream-fish assemblages is similar for functional and taxonomic perspectives. These results indicate the need for future studies on biodiversity and ecosystem function to explicitly examine functional diversity, or at least incorporate functional attributes of individuals, in order to gain a holistic understanding.Item Functional groupings of stream fishes: spatiotemporal variation, predictability, and patterns of diversity(Texas Tech University, 2005-12) Higgins, Christopher L.; Strauss, Richard E.; Wilde, Gene R.; Schmidt, Kenneth A.; Willig, Michael R.; Winemiller, Kirk O.Biodiversity and ecosystem function is a contemporary topic at the forefront of ecology. It is driven by the fundamental need to understand how the loss of biodiversity, which is occurring all around the world, affects goods and services obtained from ecosystems. The scientific literature indicates functional attributes of species strongly influence ecosystem properties; however, a lack of understanding exists regarding the relationship among functional diversity, taxonomic diversity, and community structure. As a result, this dissertation contributes to our understanding of the relationship between biodiversity and ecosystem function by analyzing the organization of stream-fish assemblages from a functional and taxonomic perspective and by synthesizing the relationship between the two aspects of biodiversity. I used a combination of previously published data, which covered broad biogeographic areas, and my own field work to address various issues on multiple spatial and temporal scales. I focused exclusively on stream-fish assemblages because they are one of the most underrepresented groups of animals in biodiversity and ecosystem function research and because they play an important role in aquatic ecosystems by removing other plants and animals from the community, actively produce fragments or feces containing the bodies of their prey, and by mechanically disturbing substrates, thereby increasing suspension of materials in the water column. In general, I found functional redundancy within stream-fish assemblages, with functional groups dividing niche space more evenly than species whether looking at the entire state, ecoregions, river basins, or individual locations, and the spatial and temporal structure of stream-fish assemblages is similar for functional and taxonomic perspectives. These results indicate the need for future studies on biodiversity and ecosystem function to explicitly examine functional diversity, or at least incorporate functional attributes of individuals, in order to gain a holistic understanding.Item The origins, maintenance, and conservation of biodiversity in spatial networks(2009-08) Economo, Evan Philip; Keitt, Timothy H.Biodiversity is distributed unevenly across geographic space and the tree of life. A key task of biology is to understand the ecological and evolutionary processes that generate these patterns. I investigate how the structure and geometry of a landscape, for example the sizes and arrangements of islands in an archipelago, affects processes contributing to the generation and conservation of biodiversity patterns. In the first chapter, I integrate two disparate bodies of theory, ecological neutral theory and network theory into a powerful new framework for investigating patterns of biodiversity in a complex landscape. I examine the consequences of network structure, such as size, topology, and connectivity, for diversity patterning across the metacommunity. The second chapter focuses on how the position of a node within a network controls local community (node) diversity. Network statistics, such as node centrality, are found to predict diversity patterns with more central nodes accumulating the most diversity. In the third chapter, I use the theory to evaluate how well fundamental concepts in conservation biology perform when neutral metacommunity processes generate diversity patterns. I find that contemporary diversity patterns are poor predictors of the long-term capacity of a network to support diversity, challenging a host of conservation concepts and applications. In the fourth chapter, I consider biodiversity dynamics in a network with a different model of speciation, where spatial structure is needed for divergence. In this case, speciation hotspots form where the dispersal properties of an organism and the spatial structure of the landscape coincide. In the final chapter I study the biodiversity of a natural structured metacommunity, the ants of the Fijian archipelago. I used a variety of collecting techniques to inventory the ant species occurring across a system of islands in the southwest Pacific. Approximately 50 new species were discovered, and the distributions of the ant species across the islands are firmly established. Radiations are observed in the genera Pheidole, Camponotus, Lordomyrma, Leptogenys, Cerapachys, Strumigenys, Poecilomyrma, and Hypoponera.Item Patterns in biodiversity and distribution of benthic Polychaeta in the Mississippi Canyon, Northern Gulf of Mexico(Texas A&M University, 2006-04-12) Wang, YuningThe distribution of benthic polychaetes in the Mississippi Canyon was examined to evaluate impacts of environmental variables on species assemblages. Environmental variables considered included depth, bathymetric slope, hydrographic features, sediment grain size, food availability and sediment contamination. Samples were collected using GOMEX boxcorer. Density decreased with increasing depth exponentially. Diversity exhibited a unimodal pattern with depth with a maximum value in the intermediate depth range (about 1269 m). Deposit feeders were the most abundant feeding guild. Both the feeding guilds and faunal composition could be divided into three groups along the depth gradient: shallow (300 ?? 800 m), intermediate (800 ?? 1500 m) and deep (> 1500 m). Results of statistical analyses revealed that depth was the most important determinant in organizing polychaete assemblages in the study area. The Mississippi Canyon and the Central Transect (a non-canyon area) were found not contaminated by trace metals or Polynuclear Aromatic Hydrocarbons (PAHs) in sediments, although the highest PAHs concentration occurred at the head of the Canyon, MT1. The mean density was higher in the Mississippi Canyon (1668 N/m2) than in the Central Transect (979 N/m2), while the mean diversity in the Canyon (ES(100) = 26.9 ) was lower than the Central Transect (ES(100) = 33.1). Large amounts of terrigenous input from the Mississippi River to the Canyon could enhance polychaete density and accelerate competitive exclusion, and thus lead to lower diversity. The faunal composition was significantly different between the two transects, with higher species richness in the Mississippi Canyon (301 species). This could be attributed to structure complexity in the Mississippi Canyon. The distribution of feeding guilds was similar between two transects. The differences observed in polychaete assemblages between two transects may be largely due to high terrigenous sediment and organic matter input to the Mississippi Canyon by the Mississippi River.Item The use of modern digital technology to store and serve biodiversity data for research and educational purposes(2015-12) Brenskelle, Laura Marie; Rowe, Timothy, 1953-; Bell, Christopher J; Brown, Matthew; Karadkar, UnmilHerein I describe two different projects I completed during the course of my Master’s at The University of Texas at Austin. These projects broadly focused on the application of technology to maintain scientific data for research and education. The first chapter is a case study of a website I developed as part of a group project in a graduate database management course. Our group took a module from proprietary instructional software developed in the 1990s, and moved it into an online format with a MySQL database on the backend. In chapter one, I provide the appropriate documentation for this project to be expanded in the future. The second chapter describes a project where I interviewed collection managers of natural history collections about their database practices. These practices have implications for the downstream use of these data for research, education, and conservation. As technology inevitably advances, this thesis will serve as a historical snapshot of modern practices, and today, it can provide a starting point of how to further the emerging discipline of biodiversity informatics.Item Values and decisions in biological conservation(2012-12) Frank, David Moorfield; Sarkar, Sahotra; Dancy, Jonathan; Dever, Josh; Dyer, Jim; Juhl, Cory; McShane, Katie; Norton, BryanConservation science applies research in the natural and social sciences to practical problems of nature conservation, thus presupposing various goals and values. This dissertation examines normative roles for the decision sciences in biological conservation. I am primarily concerned with two philosophical problems that arise in applications of the decision sciences to biological conservation problems: commensurability of multiple values and cooperation between multiple agents. I argue that models from decision analysis should be used to construct preferences over complex tradeoffs, and game theoretical models should be used to identify situations in which multiple agents pursuing their own interests cause outcomes that are worse for everyone. While these models allow values to be made explicit for decision-making, in other situations conservationists’ goals and values are obscure. I discuss this distinct problem in the context of conservation biology, where the central concept of biodiversity is analyzed and shown to necessarily reflect the values of its users. The multiplicity of meanings of ‘biodiversity’ and measures of biological diversity raise risks for conservation biology and motivate multi-criteria approaches to conservation decision-making. Finally, the goals and values of conservation scientists and landscape managers may or may not reflect those of people who are affected by conservation policies. I argue that while decision science can aid in making values of various stakeholder groups explicit, facilitating reflection and learning, it cannot resolve ethical dilemmas on its own without input from normative and applied ethics, particularly in identifying legitimate stakeholders and weighing multiple biological concerns against concerns for rights, welfare, and social justice.