Digital Commons Network^™

Rice Growing Environment Of The Ibagué Belt, Colombia: An Ecological Study At The Geotope Scale, Alexander Martínez Rivillas, William Barragán Zaque

The Geographical Bulletin

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Based on the biophysical and socioecological primary information collected and analyzed by the authors in two geotopes of the rice growing area of the Ibague region (Colombia, south America), an ecological study of the rice landscape is offered by means of using the GTP method (Geosystem, Territory, and Landscape) of Bertrand. We aspire to obtain an integrated vision of this environment on the scale of geotopos. It is shown that these spatial units can support a study of an “environmental landscape” inspired by Bertrand’s epistemology. T he research applies the principles of the GTP, traditionally conceived for the study of …

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Effects Of Patch Size, Fragmentation, And Invasive Species On Plant And Lepidoptera Communities In Southern Texas, James A. Stilley, Christopher A. Gabler

Biology Faculty Publications and Presentations

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Simple Summary

Human land use has removed habitats, separated habitats into small and disconnected fragments, and introduced foreign species, which all harm wildlife. South Texas is highly diverse and home to many endangered species, but human disturbance threatens its wildlife. In south Texas, we poorly understand how different aspects of human land use influence wildlife diversity and abundance. We studied this by surveying plants and butterflies in 24 habitat fragments in south Texas that differed in size, shape, type, and land use history. Human disturbance was extensive, and foreign and weedy species were dominant in most habitats. Habitat types had …

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Exploring Linkages Between Landscape Patterns And Freshwater And Estuarine Bivalves In The Coast Range Of Oregon, Kaegan Michael Scully-Engelmeyer

Dissertations and Theses

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Spatial configurations of landscape variables (biotic, abiotic, and socio-ecological) affect and are affected by ecological processes and species in watersheds. This dissertation explores relationships among landscape patterns, ecosystem processes and bivalve species dynamics in coastal watersheds in Oregon, USA. I approached this broad topic through two primary avenues of research: investigating cross-ecosystem threats from pesticide use in forestland management to downstream aquatic environments, and the landscape ecology of an at-risk freshwater mussel species.

Terrestrial land use activities present cross-ecosystem threats to riverine and marine species and processes. Specifically, pesticide runoff can disrupt hormonal, reproductive, and developmental processes in aquatic organisms, …

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Using Principles Of Seascape Ecology To Consider Relationships Between Spatial Patterning And Mobile Marine Vertebrates In A Seagrass-Mangrove Ecotone In Bimini, Bahamas, Sarah Rebecca Taylor Driscoll

Antioch University Dissertations & Theses

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Seagrass meadows and mangrove forests are ecologically and economically important systems that are increasingly threatened by anthropogenic activity. This study used a non-invasive method, baited remote underwater video systems (BRUVS), to observe mobile marine vertebrates in the seagrass-mangrove ecotone in North and South Bimini, the only area where mangroves remain in the northwestern Bahamas. An extensive area of mangroves and seagrass was removed for coastal development in North Bimini, where a marine protected area, the North Bimini Marine Reserve (NBMR), has been under consideration for decades. This research applied principles of seascape ecology to assess species abundance, diversity, and richness …

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Quantifying Amphibian Range Fragmentation In The Southeastern United States, Catherine E. Newman, Christopher C. Austin

Faculty Publications

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© the authors. An often overlooked component of research on factors that drive amphibian geographic distributions is description of species range shape. Broad-scale range disjunction has implications for phylogeography, ecology, and conservation, but descriptions of fragmentation are usually based on subjective visual assessment of range maps. Here, we describe a method for objectively quantifying range fragmentation and use this method to describe the patterns of amphibian species range shapes in the southeastern United States, home to the highest amphibian species richness in North America. Species ranges varied widely in degree of fragmentation, from completely contiguous to highly fragmented, and degree …

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Managing Cities As Urban Ecosystems: Fundamentals And A Framework For Los Angeles, California, Isaac T. Brown

Cities and the Environment (CATE)

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Ecosystem-based frameworks offer a robust platform for managing complex ecological challenges associated with land management. Actionable frameworks for urban ecosystems are just emerging, and the purpose of this essay is to support advancing application in city management contexts. Comprehensive urban ecosystem frameworks have the potential to synergize interrelated, yet often siloed, urban environmental management themes including urban biodiversity and natural features, pollution management, ecosystem services enhancement, and natural hazards; particularly as urban sustainability, resiliency, and infrastructure initiatives increasingly reshape cities and elevate consideration of these topics. This essay begins with a review of fundamentals of urban ecosystems across multiple relevant …

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Site-Specific Habitat And Landscape Associations Of Rusty Blackbirds Wintering In Louisiana, Sinead Mary Borchert

LSU Master's Theses

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The Rusty Blackbird (Euphagus carolinus) has gained notoriety in recent years as one of the fastest declining North American bird species, with a global population loss of as much as 95%. Causes of the decline are not completely understood, but the high rate of forested wetland change in the southeastern United States suggests that wintering habitat degradation may be a primary driver. To better inform management on critical wintering grounds, I surveyed 68 sites in Louisiana where Rusty Blackbirds had been known to occur to address how occupancy changes with habitat type and colonization and extinction rates vary with ground …

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Spatial Dynamics Of Vegetated Seascapes And The Influence On Fish And Crustaceans, Rolando O. Santos Corujo

Open Access Dissertations

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My dissertation adopted concepts and spatial tools of seascape ecology, the marine counterpart of landscape ecology, to understand the broad-scale structural attributes that make submerged aquatic vegetation (SAV) seascapes resilient to anthropogenic disturbances, drivers of fauna community structure, and productive fisheries habitats. My research was designed to address the relative and interrelated ecological effects of broad-scale changes in SAV habitat amount (habitat loss) and configuration (fragmentation). SAV seascapes in nearshore areas of Biscayne Bay have been subject to constant anthropogenic disturbances associated to freshwater pulses from canals over the last 50 years; thus, these seascapes served as a model system …

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Spatial Complexity In Fragmenting Amazonian Rainforests: Do Feedbacks From Edge Effects Push Forests Towards An Ecological Threshold?, Graeme S. Cumming, Jane Southworth, Xanic J. Rondon, Matthew Marsik

United States Department of Commerce: Staff Publications

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Deforestation and resulting landscape fragmentation are important concerns in many tropical areas. Deforestation is a complex process with many potential feedback loops, many of which are ignored in models that attempt to interpolate forest loss based on past deforestation rates. In addition, most ecological studies of the impacts of deforestation have focused on landscapes that are already fragmented. These studies ignore the fact that edge effects, such as anthropogenic fire, reach their maximum well before habitat connectivity is lost and may create positive feedbacks that result in further fragmentation. We developed a simple model to explore the potential influence of …

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The Influence Of Spatial Scale On Landcover And Avian Community Relationships Within The Upper Green River Watershed, Ky, Cabrina L. Hamilton

Mahurin Honors College Capstone Experience/Thesis Projects

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Landscape ecology studies are needed to aid land managers and conservationists in developing management plans that will effectively improve avian population trends. This study uses riparian avian point count survey data and landcover data to examine the possible relationships between riparian avian communities and landcover within the Upper Green River watershed. How avian-landcover relationships change with increasing spatial scale is also examined. Results showed unexpected avian-landcover relationships for specific species. A landcover gradient from open and successional habitat to closed, forest habitat was most prevalent in the study area and explained most of the variation within the avian datasets. Riparian …

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Linking Adult Reproduction And Larval Density Of Invasive Carp In A Large River, Michael J. Vanni, Kristin K. Arend, Mary T. Bremigan, David B. Bunnell, James E. Garvey, Maria J. Gonzalez, William H. Renwick, Patricia A. Soranno, Roy A. Stein

Publications

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Eeotogists increasingly recognize the need to understand how landscapes ami food webs interact. Reservoir ecosystems are heavily subsidized by nutrients and detritus from surrounding watersheds, and ofren contain abundant populations of gizzard shad, an omnivorous ftsh that consumes plankton and detritus. Gizzard shad link terrestrial landscapes ami pelagic reservoir food webs by consuming detritus, translocating nutrients from sedimctn detritus to the water column, and consuming zooplaukton. The abundance of gizzard shad increases with watershed agricuhuralization, most likely through n variety oj mechanisms npeniting on ttuvat and adult life stages. Gizzard shad have myriad effects on reservoirs, including impacts on nutrients, …

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Severe Wind And Fire Regimes In Northern Forests: Historic Variability At The Regional Scale, Lisa A. Schulte-Moore, David J. Mladenoff

Lisa A. Schulte Moore

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Within the northern Great Lakes region, mesoscale (10s to 100s of km2) forest patterning is driven by disturbance dynamics. Using original Public Land Survey (PLS) records in northern Wisconsin, USA, we study spatial patterns of wind and fire disturbances during the pre-Euroamerican settlement period (ca. 1850). Our goals were: (1) to determine how effectively wind and fire disturbance can be econstructed from the PLS, (2) to assess the roles of wind and fire in shaping vegetation patterns, (3) to evaluate landscape to regional controls of wind and fire regimes, and (4) to assess the potential for interactions between these disturbances. …

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Herbivore Movement And Spatial Population Dynamics In A Heterogeneous Landscape, Kyle Jonathan Haynes

LSU Doctoral Dissertations

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To date, few metapopulation studies have isolated the effects of the intervening matrix from other attributes of landscape structure (e.g., patch geography or quality) that might influence dispersal among patches. Furthermore, there has been little exploration of the mechanisms underlying effects of the matrix on the spatial ecology of species. In this dissertation, I examine how the movement and distribution of the planthopper Prokelisia crocea within and among host-plant patches (prairie cordgrass, Spartina pectinata) is affected by the composition of the matrix (the invasive grass smooth brome [Bromus inermis], native non-host grasses, or mudflat). First, using a mark-recapture study in …

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The Relative Importance Of Patch Area And Perimeter–Area Ratio To Grassland Breeding Birds, Christopher J. Helzer, Dennis E. Jelinski

School of Natural Resources: Faculty Publications

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Habitat fragmentation has been implicated as a major cause of population decline in grassland birds. We tested the hypothesis that a combination of area and shape determines the use of grassland patches by breeding birds. We compared both species richness and individual species presence in 45 wet meadow grasslands in the floodplain of the central Platte River, Nebraska. Bird data were collected through the use of belt transects and supplemented by walking and listening outside transects. Our data supported our primary hypothesis that perimeter–area ratio, which reflects both the area and shape of a patch, is the strongest predictor of …

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