Diversos aspectos metabólicos e comportamentais possuem uma estreita relação com as condições do ambiente, havendo um compromisso entre as condições naturais e a dinâmica de modificações sobre os organismos. Devido ao grande índice de degradação ambiental proveniente da atividade humana nos últimos tempos, populações de anfíbios têm sido particularmente mais afetadas devido a sua alta sensibilidade a alterações ambientais. Em uma paisagem fragmentada, a manutenção de metapopulações viáveis é um importante fator a persistência das populações. Dentro deste contexto, este estudo propõe investigar as relações entre a fragmentação florestal e habilidade das algumas espécies de anuros para se deslocar entre os fragmentos, ou entre estes e corpos d\'água. Assim, realizamos comparações, fisiológicas e comportamentais intra e interespecífica de espécies de anuros residentes em paisagens contínuas e fragmentadas em duas localidades da Floresta Atlântica, com base em suas características morfológicas. De acordo com nossos resultados, as diferenças ambientais entre as paisagens estão relacionadas com as diferenças morfofisiológicas entre as espécies. / In the last few decades, human activity has changed environmental condition, resulting in amphibian populations decline all around the world. In this study we analyze the relationships between forest fragmentation and the ability of some frog species to move between forest fragments or between fragments and breeding sites. Our study focus relies on anuran locomotor performance and supporting physiology, and the relationship between these traits and resistance to forest fragmentation. We compare morphological, physiological and behavioral traits between populations of anurans species living in different landscapes (continuous or fragmented) of two sites in the Atlantic Forest. According to our data, differences in environmental conditions of landscape are related to morpho-physiological traits. This relationship, however, depends on the site of the Atlantic Forest and also varies between species.

There is a growing need to address the effects of roadway presence on wildlife. Not only do roads directly impact gene dispersal from a movement perspective, but they limit movement of the individual animal from a habitat perspective by presenting an artificial barrier between one area of viable habitat and another. For this reason it is becoming increasingly important to quantify contact between humans and wildlife and to develop better methods for mitigating these types of conflicts. Studying habitat connectivity and animal mobility in the context of roads can provide actionable information on how, where, and when these encounters might occur in order to minimize the effects transportation networks have on wildlife. This study uses two different approaches for studying wildlife-road interactions: (1) quantifying habitat fragmentation caused by roads and (2) directly quantifying wildlife interaction with roadways. This was achieved through the development and extension of methods found in the fields of landscape ecology and time geography. First, this study demonstrates the utility of one newly created road-based landscape metric through a detailed case study via the creation of an original ArcGIS toolbox. Second, this study develops a new time-geographic methodology to probabilistically measure and predict where wildlife interactions are most likely to occur on road networks. Additionally, it is important to ensure these methods not only quantify effects of roads from habitat and movement perspectives but can be used to mitigate these conflicts in real world conservation settings. Each of these approaches individually leverages techniques found in the field of spatial optimization to strategically locate wildlife crossing structures. This study developed two new methodologies to quantify where, when, and how wildlife interactions with roads are most likely to occur: the first using road-based landscape metrics and the second using a probabilistic voxel-based time-geographic approach. To address habitat connectivity issues, one road-based landscape metric was validated on a real world data set and further advanced by developing a GIS-based tool for real world applications. Utilizing landuse and roadway layers in combination with user specified parameters, the script tools developed here readily calculate this road-based landscape metric for a given study area. To address wildlife mobility issues, probabilistic space-time prisms were used to quantify interaction probabilities between wildlife and roads. These prisms were generated for a given set of tracking points and overlaid with an intersecting roads layer in GIS. Summing the probabilities at prism-roadway intersections revealed a pattern in the likelihood of animal-roadway interactions. Finally, each method was expanded to capture habitat fragmentation and animal movement in the presence of roads over large spatial scales using location analysis techniques. This research also develops and implements new methods that explicitly address wildlife-road interactions and aid in siting potential wildlife crossing structures. Since this study directly addresses effects of roadway presence on wildlife, the techniques developed here offer an alternative approach versus existing methods from a habitat and wildlife movement perspective. These methods can aid planners in the conservation of wildlife whose habitat has been impacted by road development by identifying and targeting areas of high impact.

Master of Science / Department of Biology / Alice Boyle / Species extinctions over the past two centuries have mainly been caused by habitat destruction. Landscape change typically reduces habitat area, and can fragment contiguous habitat into remnant patches that are more subject to anthropogenic disturbance. Furthermore, changes in the landscape matrix and land-use intensification within remaining natural areas can reduce habitat quality and exacerbate the consequences of habitat loss and fragmentation. Accordingly, wildlife conservation requires an understanding of how landscape structure influences habitat selection. However, most studies of habitat selection are conducted at fine spatial scales and fail to account for landscape context. Temperate grasslands are a critically endangered biome, and remaining prairies are threatened by woody encroachment and disruptions to historic fire-grazing regimes. Here, I investigated the effects of habitat area, fragmentation, woody cover, and rangeland management on habitat selection by two species of declining grassland-obligate sparrows: Henslow’s Sparrows (Ammodramus henslowii) and Grasshopper Sparrows (A. savannarum). I conducted >10,000 bird surveys at sites located throughout eastern Kansas, home to North America’s largest remaining tracts of tallgrass prairie, during the breeding seasons of 2015 and 2016. I assessed the relative importance of different landscape attributes in determining occurrence and within-season site-fidelity of Henslow’s Sparrows using dynamic occupancy models. The species was rare, inhabited <1% of sites, and appeared and disappeared from sites within and between seasons. Henslow’s Sparrows only settled in unburned prairie early in spring, but later in the season, inhabited burned areas and responded to landscape structure at larger scales (50-ha area early in spring vs. 200-ha during mid-season). Sparrows usually settled in unfragmented prairie, strongly favored Conservation Reserve Program (CRP) fields embedded within rangeland, avoided trees, and disappeared from hayfields after mowing. Having identified fragmentation as an important determinant of Henslow’s Sparrow occurrence, I used N-mixture models to test whether abundance of the more common Grasshopper Sparrow was driven by total habitat area or core habitat area (i.e. grasslands >60 m from woodlands, croplands, or urbanized areas). Among 50-ha landscapes containing the same total grassland area, sparrows favored landscapes with more core habitat, and like Henslow’s Sparrows, avoided trees; in landscapes containing ~50–70% grassland, abundance decreased more than threefold if half the grassland area was near an edge, and the landscape contained trees. Effective conservation requires ensuring that habitat is suitable at spatial scales larger than that of the territory or home range. Protecting prairie remnants from agricultural conversion and woody encroachment, promoting CRP enrollment, and maintaining portions of undisturbed prairie in working rangelands each year are critical to protecting threatened grassland species. Both Henslow’s Sparrows and Grasshopper Sparrows were influenced by habitat fragmentation, underscoring the importance of landscape features in driving habitat selection by migratory birds. As habitat loss threatens animal populations worldwide, conservation efforts focused on protecting and restoring core habitat could help mitigate declines of sensitive species.

The growing flow of people and goods around the globe has allowed new, non-native species to establish and spread in already fragile ecosystems. The introduction of invasive species can have a detrimental impact on the already established species. Thus, it is important that we understand the mechanisms that facilitate or prevent invasion. Since reaction-diffusion invasion models produce travelling waves we can study invasion by looking at the mechanisms that allow for wave propagation failure, or wave-blocking. In this thesis we consider a perturbed reaction-diffusion model in which the perturbation resides in either the reaction or diffusion term. In doing so we exploit the underlying symmetry of our problem to define a region in the appropriate parameter space that leads to wave blocking. As a demonstrative example we apply our theory to the bistable equation and consider the effects of various perturbations.

Habitat fragmentation and destruction caused by development of infrastructure such as roads threaten biodiversity. Roads act as barriers by impeding animal movements and restricting space use. Understanding factors that influence barrier effects is important to discern the impacts of habitat fragmentation and to develop appropriate mitigations. We combined telemetry and demographic data in 2008 to 2012 with remote sensing imagery to investigate barrier effects of forest roads and assess effects of traffic, road edges, and canopy gaps on space use of an endangered, endemic forest obligate, the Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis). We mapped low to high traffic roads, road edges, canopy gaps, and random lines in forests to serve as references. We determined if red squirrels included these linear features in their total and core home ranges, and used this metric as an indicator of crossing and preference for habitat adjacent to the linear features. Forest roads acted as barriers regardless of traffic volume and had long-term impacts on animal space use. Animals did not avoid entering roadside areas, and probability of crossing linear features in the forest was not affected by distance to roads. In contrast, greater canopy cover increased probability of crossing, and gaps in canopy impeded animal movements. Higher likelihood of road crossing was associated with more variable tree height and mating activity. We demonstrated that narrow forest roads with low traffic volume were barriers for forest dependent species, and suggest that gap avoidance inhibits road crossings. (C) 2016 Published by Elsevier Ltd.

Bats (Chiroptera) are usually considered as a group greatly endangered by destructing their habitats through the human activity. However, a significant part of bat species at the central Europe use human buildings as shelters, moreover the natural shelters are marginal or unknown in several species. Considering the linkage of the great part of our bat species to the fragmented area and in connection with a long term human influence on the central european landscape we ask whether at least part of our species see human activity through providing proper shelters as positive. Based on the analysis of landscape structure and ruggedness effect on density, diversity and population structure of bat assamblages acquired by standardized mist net captures located in lowlands (elevations below 500 m) of Czech Republic (204 localities, 3585 bats, 22 bat species), we found that even though most of reactions were species specific and few species seemed to be positively associated with urban environments, most of the bat species rely on the broad-leaved forest cover and other natural habitats such as water bodies. The most significant factor influencing sexual segregation for bats was ruggedness of surrounding landscape. Keywords: Bats, Chiroptera, fragmentation, Europe, temperate zone

In this paper we endeavor to test the controversial ideas that exist about the role of fragmentation in a conservation context. In line with earlier understanding, we find that habitat fragmentation alone results in a strong detrimental effect (especially for the predator population). Connecting the fragmented habitats facilitates predator survival and hence prey survival as compared to the unconnected fragmented case. Our main result is counterintuitive: in the presence of a high quality predator, connected fragmented habitats ensure a better chance for coexistence than does even the unfragmented case. We explain why a connected fragmented habitat might thus be beneficial for the stabilization of the system, and how connections between sub-habitats are able to protect prey population from over-exploitation. In the model, habitat fragmentation is separated from the effects of habitat destruction, in order to better understand how populations react to habitat transformation.

Human settlement displaces and fragments natural habitats. Design choices in the landscape directly affect both local diversity and extinction rates. This study seeks to understand how avifauna are responding to this new technology in Mississippi.

Methods are needed to predict the spatial distribution pattern(s) of forest harvests to improve large-scale timber inventories through the incorporation of spatial distribution information. In this study, land cover type change detection methods were carried out using information from 1972 thru 2005 east-central Mississippi Landsat TM data to detect the spatial distribution of clearcut forest harvests. A random pattern was observed for clearcut harvests and this and other statistical data gathered in the study will be integrated into an existing forest inventory and transportation network database. The resulting harvested and forested area predictions generated by the database will assist with determining the sustainability and availability of forest resources for existing and future forest product mills and the creation of transportation networks needed to supply raw materials and distribute end products. Other implications include assessment of the quality and spatial components of wildlife habitat and a tool for forest certification programs.

Many species naturally occupy discrete habitat patches within a mosaic of habitats that vary in quality. The Florida scrub-jay (Aphelocoma coerulescens) is endemic to Florida scrub, a habitat that is naturally patchy and greatly reduced in area over recent decades owing to development and urbanization. Because of this habitat loss, future management of Florida scrub-jays will focus on smaller, fragmented tracts of land. My study examines such a tract, Lyonia Preserve, southwest Volusia County, FL. This preserve was unoccupied by scrub-jays prior to habitat restoration. The preserve is now frequently managed exclusively for scrub-jays as a habitat island surrounded by development. Management of the preserve includes roller chopping, root raking, timbering, and "oak stripping" where islands of oak patches are left intact while the rest of the area is roller chopped. I investigate what, if any, demographic consequences may be associated with the habitat management and the spatial setting of the preserve. I used population data collected in this area since 1992 to examine population growth and responses to habitat restoration within the preserve and habitat destruction outside the preserve. I mapped territories and measured survival and recruitment of scrub-jays, and dispersal into and out of the study area, for two and a half years. Since restoration, the population has shown logistic growth, with the area supporting higher than average densities of scrub-jay family groups. Observed density of the population and territory size varied between study years. Breeder survival values were positively related to territory size and significantly lower during periods of highest observed density. However, recruitment (yearling production) showed no relationship to territory size. Dispersal to isolated habitat patches was observed; likewise, several failed dispersal events were noted. No immigration into the study area was observed; however these data may be underrepresented since not all scrub-jays in and outside of the preserve were banded, and data collection was limited during the initial colonization period. High densities inside the preserve may therefore be both a result of frequent habitat management in the form of mechanical treatment as well as crowding of individuals due to outside habitat destruction. The results indicate that carrying capacity of habitat for scrub-jays may be raised by frequent, mechanical management; however, if the area is isolated, management may result in high densities and negative demographic consequences, e.g., reduced breeder survival. Negative effects of management may be avoided by subjecting smaller areas to mechanical treatment with increased time between treatments. Land managed for Florida scrub-jays should be contiguous or connected with other scrub habitats so that surplus birds from the managed areas have a refuge and do not contribute to increased densities. Regulatory officials should use caution when allowing for "take" of scrub-jay habitat as the effects may extend beyond the local habitat being destroyed.