This study investigated bird distributions in relation to local habitat and landscape pattern and the implications which habitat fragmentation may have for woodland birds. There were two sections to the research: an experimental study investigating bird gap crossing behaviour across distances of five to 120m; and an observational study modelling woodland bird distributions in relation to local habitat and landscape scale variables in two study areas (East Loch Lomond and the Central Scotland Forest). In the experimental study it was hypothesised that bird willingness to cross gaps will decrease with increasing gap distance even at home-range scales and that the rate of decline will vary interspecifically in relation to bird morphology. Song thrush mobbing calls played at woodland edges in the West of Scotland were used to attract birds across gaps and results were compared with the response along woodland edges. Data were obtained for four species: chaffinch, coal tit, robin and goldcrest. The decline in response with distance across gaps and along woodland edge was modelled for each species using generalized linear modelling. Maximum gap crossing distances ranged from 46m (goldcrest) to 150m (extrapolated value for the chaffinch). Goldcrests responded more readily through woodlands. There was no difference between woodland edge and gap response for the coal tit. Robins and chaffinches however responded more readily across gaps than through woodland. When different response indices were plotted against bird mass and wing area, results suggested that larger birds with bigger wings responded more readily across gaps than through woodland. It is suggested that this relates to differences in bird manoeuvrability within woodlands and ability to evade a predator in gaps. Fragmentation indices were calculated for an area of the Central Scotland Forest to show how willingness to cross different gap distances influences perception of how fragmented the woodlands are in a region. Results are discussed in the context of the creation of Forest Habitat Networks. The data for the observational section of the work was from bird point counts for 200 sample points at East Loch Lomond in 1998 and 2000 and 267 sample points in the Central Scotland Forest in 1999. In addition a time series of point count data was available for 30 sample points at East Loch Lomond. Additional data was gathered for ten sample points (1998) and two sample points (2000) at East Loch Lomond to investigate effects of observer, time and weather on count data. Generalized linear and generalized additive modelling was carried out on these additional data. Results indicated that biases due to the variation in time and weather conditions between counts existed in the pure count data but that these were eliminated by reducing data to presence and absence form for analysis. Species accumulation curves indicated that two counts per sample point were insufficient to determine species richness. However a sufficiently large proportion of the species was being detected consistently in two counts of ten minutes duration for it to be valid to model them in relation to habitat and landscape variables. Point count data for East Loch Lomond in 1998 (ELL98) and the Central Scotland Forest in 1999 (CSF99) for the wren, treecreeper, garden warbler, robin, blue tit, blackbird, willow warbler, coal tit, goldcrest, great tit, and song thrush were analysed using generalized additive modelling. In addition models were built for the blackcap (CSF99) and the siskin, redstart and wood warbler (ELL98). Where all relationships were identified as linear, models were rebuilt as GLMs. Models were evaluated using the Area Under the Curve (AUC) of Receiver Operating Characteristic (ROC) plots. AUC values ranged from 0.84-0.99 for ELL98 and from 0.76-0.93 for CSF99 indicating high predictive accuracy. Habitat variables accounted for the largest proportion of explained variation in all models and could be interpreted in terms of bird nesting and feeding behaviour. However additional variation was explained by landscape scale and fragmentation related (especially edge) variables. ELL98 models were used to predict bird distributions for Loch Lomond in 2000 (ELL00) and for the CSF99. Likewise the CSF99 models were used to predict distributions for ELL98 and ELL00. Predicted distributions had useful application in many cases within the ELL site between years. Fewer cases of useful application arose for predicting distributions between sites. Results are discussed in the context of the generality of bird environment relationships and reasons for low predictive accuracy when models are applied between sites and years. Models which had useful application for ELL00 were used to predict bird distributions for 2025 and 2050 at East Loch Lomond. Habitat and landscape changes were projected based on the proposed management for the site. Since woodland regeneration rates are difficult to predict, two scenarios were modelled, one assuming a modest amount of regeneration and one assuming no regeneration. Predictions derived from the ELL98 models showed broad-leaved species increasing in distribution while coniferous species declined. This was in keeping with the expected changes in the relative extent of broad-leaved and coniferous habitat. However, predictions from the CSF99 models were often less readily explicable. The value of the modelling approach is discussed and suggestions are made for further study to improve confidence in the predictions.

Includes bibliographical references (p. 301-319). Palaeoecological records, documented historical records and remnant vegetation were investigated in order to construct a multi-scaled history of vegetation pattern and change in the Fleurieu Peninsula, South Australia over the last c. 8000 years. Aims to better understand post-European landscape transformation and address the inherently historical components of the problems of regional biodiversity loss, land sustainability and the cumulative contribution to global climatic change.

"September 2002" Bibliography: leaves 77-85. Examines the persistence of the yellow-footed antechinus using live trapping in small, remnant patches and strips of forest, to document autecological sata and the investgate occurrence, breeding activity and inter-patch movements. Radio-tracking was conducted to compare home range properties of lactating females in restricted and unrestricted habitat.

Includes bibliographical references (p. 301-319). / xx, 319, [30] leaves : ill. (some col.), maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Palaeoecological records, documented historical records and remnant vegetation were investigated in order to construct a multi-scaled history of vegetation pattern and change in the Fleurieu Peninsula, South Australia over the last c. 8000 years. Aims to better understand post-European landscape transformation and address the inherently historical components of the problems of regional biodiversity loss, land sustainability and the cumulative contribution to global climatic change. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geographical and Environmental Studies, 2001

Habitat loss and fragmentation is a crisis affecting wildlife worldwide. In Tanzania, East Africa, a dramatic and recent (<80 years) expansion in human settlement and agriculture threatens to reduce gene flow among protected areas for many species of large mammals. Wildlife linkages can mitigate population isolation, but linkage designs lacking empirical justification may be controversial and ineffective. Connectivity conservation requires an understanding of how biogeographic factors shaped gene flow prior to habitat loss or fragmentation, however the history of interaction among populations is rarely known. The goal of my study was to provide context for connectivity conservation in central and southern Tanzania by identifying landscape features that have shaped gene flow for three ungulate species with different dispersal capabilities. I investigated historical patterns of connectivity for Maasai giraffe (Giraffa camelopardalis tippelskirchi), impala (Aepyceros melampus), and eland (Tragelaphus oryx) by estimating genetic structure among four to eight protected areas per species. Genetic structure changes very slowly among large populations and thus is likely to reflect historical processes instead of recent anthropogenic influences. I collected noninvasive DNA samples and generated microsatellite genotypes at 8 to 15 loci per species, then estimated genetic diversity metrics (allelic richness, AR, and expected heterozygosity, H[subscript E]) for each population (defined by reserve). I also calculated genetic distance (F[subscript ST] and Nei's unbiased genetic distance, D[subscript hat]) and an estimate of gene flow (Nm) between all population pairs for each species. To elucidate the possible causes of genetic structure between these populations, I tested for isolation by distance and isolation by resistance based on a suite of biogeographic factors hypothesized to affect gene flow. To do this, I created GIS-based resistance surfaces that assigned different costs of movement to landscape features. I created one or more resistance surfaces for each hypothesis of landscape effect. I used circuit theory to estimate the cumulative resistance between each pair of reserves for each weighting scheme, and then performed Mantel tests to calculate the correlation between these resistances and the observed population pairwise genetic distances (D[subscript hat]). I chose the optimal resistance model for each species as the model that was most highly correlated with observed genetic patterns. To verify that the correlation of resistance models with genetic distance was not an artefact of geographic distance, I performed partial Mantel tests to calculate correlation while controlling for the effect of geographic distance. Finally, I compared historical gene flow patterns to the distribution of contemporary human activity to predict areas that are at risk of a loss of connectivity. Indices of genetic diversity were moderate for all three species and comparable to previously reported values for other savannah ungulates. Diversity (both H[subscript E] and A[subscript R]) was highest in eland and lowest in giraffe for these populations, and was not consistently correlated with reserve size as has been reported for other species in East Africa. Although patterns in genetic distance were broadly similar across all three species there were also striking differences in connectivity, highlighting the importance of cross-species comparisons in connectivity conservation. At this scale, resistance models based on slope strongly predicted population structure for all three species; distance to water was also highly correlated with genetic distance in eland. For all three species, the greatest genetic distances occurred between populations separated by the Eastern Arc Mountains, suggesting that the topography of this area has long acted as a barrier to gene flow, but this effect is present in varying degrees for each species. I observed high levels of historical gene flow between centrally located populations (Ruaha National Park and Rungwa Game Reserve) and those in the southwest (Katavi National Park and Rukwa Game Reserve). Although human settlement in this area has been low relative to other areas, the connection between the Katavi/Rukwa and Ruaha ecosystems may be threatened by increased human activity and warrants conservation. High levels of historical gene flow were also seen between reserves in the northeast (Tarangire National Park, Swagaswaga Game Reserve) and the central and southwest populations. These connections appear highly threatened due to current land use practices, and may have already suffered a loss of gene flow. Field surveys in the lands surrounding the northeastern reserves are needed to quantify current levels of connectivity and determine whether corridors could be established to maintain or restore gene flow with other reserves. / Graduation date: 2012

Understanding the mechanisms that regulate local species diversity and community structure is a perennial goal of ecology. Local community structure can be viewed as the result of numerous local and regional processes; these processes act as filters that reduce the regional species pool down to the observed local community. In stream ecosystems, the natural flow regime (including the timing, magnitude, and duration of high and low flow events) is widely recognized as a primary regulator of local diversity and community composition. This is especially true in aridland streams, where low- and zero-flow events can occur frequently and for extended periods of time (months to years). Additionally, wetted habitat patches in arid-land stream networks are often fragmented within and among stream networks. Thus dispersal between isolated aquatic patches may also play a large role in regulating local communities. In my dissertation, I explored the roles that drought, dispersal, and local habitat factors play in structuring arid-land stream communities. I examined the impact of flow permanence and seasonal variation in flow and other abiotic factors on aquatic communities at both fine spatial scales over a long time period (8 years; Chapter 2) and at a broad spatial scale over a shorter time period (1-2 years; Chapter 4). Additionally, I quantified aquatic invertebrate aerial dispersal over moderate spatial scales (��� 0.5 km) by conducting a colonization experiment using artificial stream pools placed along and inland from two arid-land streams (Chapter 4). Finally, I examined the roles of spatial isolation, microhabitat type, and local abiotic and biotic factors in structuring aquatic communities in freshwater oases scattered across one of the most arid regions of North America, the southern Sonoran Desert (Chapter 5). In Chapter 2, I found that severe drought caused an unprecedented drying event in isolated perennial stream pools, and that several additional drying events occurred over the following four years. This transition to intermittent flow caused the extirpation of several large, long-lived species with low dispersal abilities (including the top predator) and drove the local community into an alternative state. In the colonization experiment described in Chapter 3, I found that several arid-land stream invertebrate taxa disperse widely and frequently. The widespread dispersers identified by this experiment included several of the earliest colonist taxa observed following the severe drought described in Chapter 2. Other taxa, though, only dispersed overland after receiving an environmental cue (rainfall) or preferentially dispersed along stream corridors. In Chapter 4, where I examined invertebrate community structure across a large network of well-connected intermittent and perennial reaches, I found low diversity in intermittent reaches, regardless of their connectivity to diverse upstream perennial reaches. These species-poor, intermittent communities were composed of a unique suite of species with lifehistory adaptations that conferred desiccation resistance, including extended egg and larval diapause stages. The short flow duration of intermittent reaches (<100 days) likely precluded upstream perennial taxa from establishing populations in downstream intermittent reaches before drying occurred, while the relative predictability of flow timing (Dec-Apr) likely allowed for a small number of species to develop appropriate life-history traits (e.g., diapause stage, rapid development time) to exploit these temporally-fleeting habitats. In Chapter 5, I found over 220 species of aquatic animals (including ��� 5 undescribed species) in the 19 desert oases that were sampled across the southern Sonoran Desert. Local community composition in these oases was strongly driven by microhabitat type. Additionally, native aquatic species richness and abundance in these oases were significantly reduced by the introduction of tilapia, an exotic fish species. The threats to arid-land streams presented by increased drought severity, anthropogenic water withdrawals, and local habitat degradation (e.g., introduced species, unmanaged recreational use) are grave across the southwestern US and northwestern Mexico. I hope that in addition to furthering our understanding of ecological processes in arid-land streams, this dissertation makes a small contribution towards the efforts to preserve these habitats. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from July 18, 2012 - July 18, July 2013

Graduation date: 2006 / I examined the avian biogeography of the islands of Lago Gatun, Panama, in an effort to better understand the effects of forest fragmentation in this biodiverse region, and specifically to understand the importance of fragment isolation and the mechanism behind its effects on tropical bird distribution. I combined exhaustive surveys of 29 islands with an experimental release program. Analyses of these data were conducted in a hierarchical fashion to evaluate evidence for avian dispersal limitation at multiple scales. First, I assessed the potential roles of area and isolation in determining avian species richness across this series of fragments, and how these relationships may differ for edge and forest dependent birds. Next, I analyzed community structure and species distributions to determine the relative contributions of island area and isolation in creating patterns of species-specific insular occurrence. Lastly, I assessed the results of the experimental investigation to evaluate the hypothesis that dispersal limitation explains the insular distribution patterns of several tropical forest birds. Isolation is a significant predictor of avian species richness, but only after accounting for the stronger effect of area. Species-isolation relationships are different in this archipelago for birds that rely on forest and edge habitats, respectively. Species-specific distributions are significantly nested when islands are ordered by area, and by isolation once the effect of area is considered. Occurrence of most forest species is sensitive to area and isolation of the archipelago. Examination of guild structure suggests that multiple mechanisms are responsible for these occurrence patterns. There are distinct species-specific differences in ability to cross small gaps, and species which are better able to cross these gaps are more widely distributed across the archipelago than those species that negotiate the same barriers poorly. Species that performed uniformly well in release experiments were much less likely to have suffered insular extinction in the preceding 25 years than those species that showed moderate to poor experimental performance. There is strong evidence of a morphological basis for the patterns. The cumulative evidence from these analyses is the most comprehensive evidence to date of local-scale dispersal limitation in volant birds.

Eighteen prairie rattlesnakes (Crotalus viridis viridis) were tracked using radio-telemetry and 82 snakes were PIT-tagged over a 2-year period in Lethbridge, AB to determine population size, movement patterns, and habitat utilization, and to predict fragmentation effects on the species within an urban locale. Population size was estimated using closed population models at 374 snakes (295 adults) and open population models at 204 snakes (161 adults), greater than an estimate of <50 adults in 2003 (Ernst, 2003) and 2006 (Ernst & Quinlan, 2006). Mean home range sizes, based on 95% minimum convex polygon analysis, differed significantly between years (31.51 ha in 2005, 3.72 ha in 2006). Calculated movement parameters, such as mean distance moved per day, total distance moved over the course of the active season, and frequency of movement varied between years and individuals. Greater-than-expected (under hypotheses of even habitat choice) utilization was observed in habitat types located within coulee and flood plain areas, with apparent preference towards unbroken parcels of grassland or cottonwoods, whereas less-than-predicted utilization of agricultural habitat type was observed. Fragmentation effects on prairie rattlesnake movement and occurrence were examined through modeling and were found to coincide with observed species’ locations, suggesting that prairie rattlesnakes are undergoing modification of movement patterns to avoid highly concentrated human density or use. Influence of weather on the use of vegetative ground cover was observed, as it was accessed more by prairie rattlesnakes at higher temperatures. Recommendations towards future management of the prairie rattlesnake population in Lethbridge are given, including protection of the Bridge View Drive site and inclusion of varied habitat types and terrain when planning habitat and wildlife corridors. Management decisions that ensure remaining habitat parcels and connective areas near rattlesnake foraging or movement corridors are also advocated. Identification of future research focuses include studies on juvenile survivorship, genetic structure, and vehicle-related mortality. / xii, 83 leaves : col. ill., col. maps ; 29 cm

Thesis (MSc)--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: The conservation of biodiversity is becoming increasingly challenging as habitats are disturbed, fragmented or destroyed. Although nature reserves now cover more than 10 % of the earths’ surface it has become clear that more will have to be done to ensure the long-term survival of species. Therefore, focus is increasingly shifting towards conserving biodiversity in natural and semi-natural remnants in human-influenced areas. This study aimed to determine the contribution of remnants in human-influenced areas to the conservation of biodiversity in the Cape Floristic Region (CFR) lowlands, using ground-dwelling arthropods, specifically ants, as the focal taxon. Initially, base-line information of arthropods and in particular ants was obtained. Sampling arthropods generally involves a large sample effort. Therefore maximizing sampling effort for ants in the CFR was investigated by trapping ground-dwelling ants at a single locality. Doubling the number of grids of pitfall traps was found to be more effective in trapping a greater number of species than doubling the duration of sampling. Therefore increasing spatial sampling intensity rather than sampling duration maximizes sample effort for CFR ants. Also, the seasonal changes of ground-dwelling arthropods, including ants, were determined by sampling four times during the year at a single locality. Overall arthropod abundance was found to peak in summer while dropping to a minimum in winter. This pattern was mirrored by that of the ants, indicating that ant results have a broader relevance than to ants only. The ground-dwelling fauna was dominated by ants emphasizing their importance in the CFR lowlands, and demonstrating that ants are an appropriate flagship taxon for epigaeic arthropod diversity in the CFR. Finally the contribution of remnants in human-influenced areas to the conservation of the CFR was investigated. A nested hierarchical approach was used, where five localities were selected across the CFR, each containing one reserve site and one site with natural remnants. Ants were sampled, along with environmental variables, namely weather, vegetation and soil. Overall, remnants were found to support similar ant assemblages to those of reserves. However for individual localities some remnants were significantly different to their reserve counterparts. Differences in ant assemblages were found to be greater between localities than between reserves and remnants. The relatively high heterogeneity of ants found in this study emphasizes the conservation significance of invertebrates along with that of plants in the CFR. Remnants clearly show the potential to conserve ant assemblages, however correct management is needed for these areas to maximize their potential. Disturbances such as the presence of the invasive Argentine ant and increasing soil nutrients by fertilization, pose a distinct threat to the ability of remnants to conserve ant assemblages. This study has shown that remnants currently support ant assemblages representative of those present in the CFR today. Therefore, some remnant patches of habitat in agricultural areas currently do contribute highly to the conservation of a functional important taxon in this global biodiversity hotspot, and if managed correctly, may continue to do so in the future. / AFRIKAANSE OPSOMMING: Die vernietiging en fragmentering van habitatte maak die bewaring van biodiversiteit al hoe meer van ‘n uitdaging. Alhoewel natuur reservate reeds meer as 10 % van die aarde se oppervlak beslaan is dit duidelik dat meer gedoen sal moet word vir die lang-termyn voortbestaan van spesies. Dus word die fokus van biodiversiteit-bewaring toenemend gerig op bewaring van natuurlike en semi-natuurlike fragmente in menslik-beinvloede gebiede. Die doel van hierdie studie was om te bepaal wat die bydrae van fragmente van natuurlike veld in menslik-beinvloede gebiede is tot die bewaring van die streek. Dit is gedoen deur van grond-lewende geleedpotiges en spesifiek, miere in die Kaapse floraryk (CFR) gebruik te maak. Aanvanklik is kennis ingewin oor die geleedpotiges en spesifiek miere in die omgewing. Omdat die versameling van geleedpotige diere gewoonlik baie moeite vereis is ‘n maksimum steekproef gedoen by ‘n enkele lokaliteit. Daar is gevind dat ‘n verdubbling van die aantal ruitsteekproefnemings met vanggate meer effektief is om miere te vang as ‘n verdubbling in die tydperiode wat vanggate oop is. Dus, is ‘n hoër ruimtelike steekproef intensiteit meer effektief in vergelyking met ‘n langer tydsduur vir miere in die CFR. Die seisoenale veranderinge van grond-lewende geleedpotiges, sowel as miere, was ook bepaal. Dit was gedoen deur vier seisoenale steekproewe te doen by ‘n enkele lokaliteit. Die totale geleedpotige-talrykheid was die meeste gedurende die somer en die minste in die winter. Die miertalrykheid het ook hierdie patroon weerspieël. Dit dui daarop dat veranderinge in mier versamelings van breër belang is vir alle grondlewende geleedpotiges. Miere was die dominante grond-lewende geleedpotiges en beklemtoon die belangrikheid van miere in die CFR, sowel as hulle toepaslikheid as vlagskip taksa vir grond-lewende geleedpotige diversiteit in die CFR. Laastens was die bydrae van gefragmenteerde natuurlike veld in menslik–beinvloede gebiede tot die bewaring van die CFR ondersoek. ’n Krimpende/ genestelde hiërargies benadering is gebruik in vyf geselekteerde lokaliteite, elk het bestaan uit ‘n area in ‘n natuur reservaat en ‘n area in ‘n naasliggende fragment. Miere was versamel saam met ‘n verskeidenheid omgewings veranderlike, naamlik weer, plantegroei en grond. In die algemeen is gevind dat fragmente en reservate gelyksoortige mier versamelings het. Daar was wel gevind dat party fragmente aansienlik verskillend was van die reservaat teenstuk. Verskille in mier versamelings tussen lokaliteite was groter as verskille tussen reservate en fragmente. Die relatief hoë heterogeniteit van miere beklemtoon die bewaringsbelang van invertebrate saam met dié van plante in die CFR. Dit is duidelik dat fragmente wel ‘n potensiale bydrae kan maak om die mier versamelinge te bewaar, maar gepaste bestuur is nodig om hierdie potentiaal te maksimaliseer. Versteurings soos die teenwoordigheid van die indringer Argentynse mier en toenemende grondvoedingstofkonsentrasie as gevolg van bemesting is ‘n groot bedreiging tot die vermoë van fragmente om mier versamelings te bewaar. Hierdie studie wys dat mier versamelings in gefragmenterde areas verteenwordigend is van die algemene mier versamlings wat op die oomblik in die CFR is. Dus lewer party fragmente in landbou gebiede op die oomblik ‘n wesenlike bydrae tot die bewaring van ‘n funksioneel belangrike takson in hierdie globale biodiversiteitsbrandpunt en die bydra sal volhoubaar wees met korekte bestuur.

A growing body of work reveals that animal-mediated pollination is negatively affected by anthropogenic disturbance. Landscape-scale disturbance results in two often inter-related processes: (1) habitat loss, and (2) disruptions of habitat configuration (i.e. fragmentation). Understanding the relative effects of such processes is critical in designing effective management strategies to limit pollination and pollinator decline. I reviewed existing published work from 1989 to 2009 and found that only six of 303 studies separated the effects of habitat loss from fragmentation. I provide a synthesis of the current landscape, behavioral, and pollination ecology literature in order to present preliminary multiple working hypotheses to explain how these two landscape processes might independently influence pollination dynamics (Chapter 2). Despite the potential importance of independent effects of habitat fragmentation, effects on pollination remain largely untested. Studies designed to disentangle the independent effects of habitat loss and fragmentation are essential for gaining insight into landscape-mediated pollination declines. I also found that the field of landscape pollination ecology could benefit from quantification of the matrix, landscape functional connectivity, and pollinator movement behavior. To test the hypothesis that pollinator movement can be influenced by landscape configuration, I translocated radio-tagged hummingbirds across agricultural and forested landscapes near Las Cruces, Costa Rica (Chapter 3). I found return paths were on average more direct in forested than in agricultural landscapes. In addition, movement paths chosen in agricultural landscapes were more forested than the most direct route suggesting that hummingbirds avoided crossing open areas when possible. To determine if differences in pollinator movement translated to differences in plant reproduction, I tested the relative importance of landscape composition versus configuration on the reproductive success of Heliconia tortuosa, a hummingbird-pollinated forest herb (Chapter 4). I used a stratified random sampling design to select sites across orthogonal gradients in patch size, amount of forest, and elevation. I tested four landscape change hypotheses (i.e., local, landscape composition, landscape fragmentation, and fragmentation threshold). I found that Heliconia reproduction supported both the local site and landscape fragmentation hypotheses. Seed set increased with increasing forest patch size independent of amount of forest in the surrounding landscape. I also found that increasing patch size positively influenced the relative abundance of pollinators. The observed differences in seed set likely resulted from differences in hummingbird movements (Chapter 3) and/or abundance under different landscape configurations. / Graduation date: 2013