In spatially structured populations, distributional dynamics are driven by the quantity, connectivity and quality of habitat. Because these drivers are rarely measured directly and simultaneously at relevant scales, information on their relative importance remains unclear. I assessed the influence of both direct and indirect measures of local habitat quality, and of landscape habitat amount and connectivity on long-term territory occupancy dynamics of non-migratory pygmy owls. Direct measures of local habitat quality based on territory-specific reproductive output had greater effects on distribution than landscape factors, but only when spatio-temporal fluxes in performance linked to environmental stochasticity and intraspecific competition were considered. When habitat quality was measured indirectly based on habitat structure, however, landscape factors had greater effects. Although all landscape factors were important, measures of landscape connectivity that were uncorrelated with habitat amount and based on attributes of matrix structure and habitat configuration that influence dispersal movements had greater effects than habitat effective area (amount weighted by quality). Moreover, the influence of connectivity (but not habitat effective area) depended on local habitat quality. Such results suggest the relative importance of local habitat quality in driving distribution has been underestimated and that conservation strategies should vary spatially depending on both local and landscape contexts.

Area sensitivity of North American grassland birds is a significant conservation concern; yet, its causes are not known. I used point count data from 20 tall-grass prairie patches in Southern Manitoba to assess the relative importance of patch size, edge proximity, and landscape composition on the densities and species richness of grassland songbirds. The degree to which the landscape surrounding point count plots was open, as opposed to forested or urban, had a positive effect on species richness and the densities of most focal species, and was more important than patch size, edge proximity, or habitat amount. These results suggest that landscape openness, not patch size (with which it is usually correlated) drives area sensitivity. Small grassland patches embedded in open landscapes are less susceptible to area sensitivity and may be of high conservation value for grassland birds. / February 2017

Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-06-08T18:27:22Z No. of bitstreams: 2 Tese - Poliana Mendes - 2015.pdf: 2524794 bytes, checksum: eb8b9fab8d3f5746e746f1dbc2f546ab (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-06-09T11:32:11Z (GMT) No. of bitstreams: 2 Tese - Poliana Mendes - 2015.pdf: 2524794 bytes, checksum: eb8b9fab8d3f5746e746f1dbc2f546ab (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-06-09T11:32:11Z (GMT). No. of bitstreams: 2 Tese - Poliana Mendes - 2015.pdf: 2524794 bytes, checksum: eb8b9fab8d3f5746e746f1dbc2f546ab (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-06-08 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Our aim was to explore some components of bat responses to land-use changes. Bats were sampled in 18 forest patches during four nights. Landscapes were delimited with 500 meter to 10km radius from sample site. We took metrics of two different landscape components: natural vegetation amount and fragmentation (measured as number of patches). In the first chapter we tested the effect of such components in total abundance, species richness and variance in biological traits of bats. In the second chapter we verified if those variables were more important than local ones to determine occupancy probability of eight bat species. Local variables were tree density, understory height, liana quantity, and canopy cover. In the third chapter we counterposed species climatic suitable areas with spatial data about habitat loss and fragmentation in Cerrado. We predicted species vulnerability creating scenarios in which they were sensitive to habitat loss and/or fragmentation, furthermore we showed an overview of species suitable areas exposure to land-use changes to eight bat species. We observed idiosyncratic patterns of responses to habitat loss and fragmentation in bats. Abundance is positively related to habitat amount, whereas species richness, variance in body mass and number of guilds is negatively related to fragmentation. Occupancy probability of Sturnira lilium is positively related to habitat amount, whereas occupancy probability of Myotis nigricans is negatively related to fragmentation. Six other species did not show any clear relationship between occupancy and landscape structure. South areas of Cerrado are locales with higher climatic suitability, while still having higher exposure level to land-use changes. Our results strengthen the view that species response patterns to habitat loss and fragmentation are species-specific and also diversity metric specific. Such assertion reinforces that it is necessary an improvement in knowledge about factors that determine those responses, however it does not mean that the development of regional conservation strategies is unfeasible when using the current available knowledge in literature. / Esse trabalho teve como objetivo explorar alguns componentes das respostas dos morcegos a mudanças na estrutura da paisagem. Morcegos foram amostrados em 18 fragmentos florestais durante quatro noites. Foram delimitadas paisagens com entre 500 metros e 10 km de raio a partir do local de amostragem. Métricas de dois componentes da paisagem foram medidas nestas paisagens: a quantidade de vegetação natural e a fragmentação dessa vegetação (medido como o número de manchas). No primeiro capítulo testamos o efeito desses dois componentes na abundância total, riqueza de espécies e variância em traços biológicos de morcegos. No segundo capítulo verificamos se essas variáveis eram mais importantes do que variáveis locais para determinar a probabilidade de ocupação de oito espécies de morcegos. As variáveis locais foram obtidas em três quadrantes no local de amostragem de morcegos, onde se obteve a densidade de árvores, altura do sub-bosque, quantidade de lianas e, cobertura do dossel. No terceiro capítulo, a adequabilidade climática das espécies no Cerrado foi contraposta com dados espacializados da quantidade de vegetação natural e fragmentação. Essa contraposição teve como o objetivo predizer a vulnerabilidade de espécies se elas fossem sensíveis a um limiar de perda de habitat ou fragmentação na paisagem, além de mostrar de forma geral a exposição às mudanças na paisagem das áreas climaticamente adequadas para oito espécies de morcegos. Observa-se, de uma forma geral, padrões idiossincráticos de respostas a perda de habitat e fragmentação em morcegos. A abundância total é positivamente relacionada com a quantidade de habitat, enquanto que a riqueza de espécies, a variância na massa corporal e o número de guildas são negativamente relacionados com a fragmentação. A probabilidade de ocupação de Sturnira lilium é positivamente relacionada com a quantidade de habitat, enquanto que a probabilidade de ocupação de Myotis nigricans é negativamente relacionada com a fragmentação. Outras seis espécies não mostraram uma clara relação da probabilidade de ocupação com a estrutura da paisagem. Áreas do sul do Cerrado são locais com maiores valores de adequabilidade e, ao mesmo tempo, maiores exposições às mudanças na paisagem. Os resultados dos três capítulos fortalecem uma visão na literatura de que o padrão de respostas das espécies de morcegos à perda de habitat e fragmentação é específico para a espécie e para o componente de diversidade medido. Esta afirmação reforça o argumento de que um maior conhecimento sobre os fatores que determinam essas respostas é necessário, porém não inviabiliza o desenvolvimento de estratégias regionais de conservação utilizando o conhecimento já disponível na literatura.

Using metacommunity theory, I investigated the mechanisms of meta-assemblage structure and assembly among medium- to large-bodied mammals in North Texas. Mammals were surveyed with camera-traps in thirty property units of the LBJ National Grasslands (LBJNG). In Chapter II the dispersal and environmental-control based processes in community assembly were quantified within a metacommunity context and the best-fit metacommunity structure identified. A hypothesis-driven modelling approach was used in Chapter III to determine if the patterns of species composition and site use could be explained by island biogeography theory (IBT) or the habitat amount hypothesis (HAH). Islands were defined as the LBJNG property unit or the forest patch bounded by the property unit. Forest cover was selected as the focal habitat for the HAH. Seasonal dynamics were explored in both chapters. Metacommunity structure changed with each season, resulting in quasi-nested and both quasi and idealized Gleasonian and Clementsian structures. Results indicated that the anthropogenic development is, overall, not disadvantageous for this assemblage, that community assembly receives equal contributions from spatial and environmental factors, and that the metacommunity appears to operate under the mass effects paradigm. The patterns of species composition and site use were not explained by either IBT or HAH. Likely because this assemblage of generalist, dispersal-capable mammals are utilizing multiple habitat types both in the protected land and in the private land. This research highlights the versatility of these species and the potential value of rural countryside landscapes for wildlife conservation.

Understanding how habitat amount and configuration affect species richness, occurrence or abundance has been one of the major foci of research in ecology and biogeography, given its central importance for conservation planning and landscape management. We conducted bird point counts within clearcuts and mature pine stands of different sizes and configuration in working pine forest in north-central Mississippi to determine species associations. Early-successional and mature pine focal species showed varying response to the proportion and proximity of vegetation conditions in the landscape. While elements of configuration exhibited a greater influence on predicted avian abundance in this landscape, meaning many species require a mosaic of habitat conditions that come from both early-successional and mature vegetation types. Efforts to combine management of timber and conservation of songbirds must consider both species’ habitat requirements and the distribution of these requirements in the landscape.

Studien syftar till att testa teorier om effekter av habitatstorlek, konnektivitet, områdesskydd, habitatmängd och fragmentering på enskilda arters förekomstmönster, samt undersöka existensen av fragmenteringströskel och utdöendetröskel. Förekomstdata för revlummer Lycopodium annotinum och mattlummer Lycopodium clavatum har insamlats i 61 skogsfragment utspridda i 10 kartrutor à 2,5×2,5 km i landskapet Södermanland. I vardera skogsfragment undersöktes en yta om 500m2. Revlummer förekom i 13 och mattlummer i 10 av de undersökta skogsfragmenten. I 7 kartrutor förekom revlummer i minst 1 skogsfragment, för mattlummer var motsvarande siffra 8 kartrutor. Resultaten visar att habitatstorlek har en signifikant positiv effekt på förekomst av revlummer och mattlummer samt att konnektivitet har en signifikant positiv effekt på förekomst av mattlummer. Områdesskydd, habitatmängd och fragmentering i landskapet har ingen påvisad effekt på förekomst av dessa arter och ingen fragmenteringströskel eller utdöendetröskel har hittats. Dessa resultat indikerar att ett bevarande av skogsfragment med stor storlek och hög konnektivitet är viktigt för de undersökta arternas fortsatta livskraft. / The aim of this study is to test theories of the effects of habitat size, connectivity, area protection, habitat amount and fragmentation on the occurrence of single species, plus examining the existence of a fragmentation threshold and an extinction threshold. Occurrence of stiff clubmoss Lycopodium annotinum and stag’s-horn clubmoss Lycopodium clavatum was examined in 61 forest fragments scattered over 10 large 2,5×2,5 km plots, located in the county of Stockholm in Sweden. In each forest an area covering 500m2 was searched for the two species. Lycopodium annotinum occured in 13 and L. clavatum in 10 of the investigated fragments. Lycopodium annotinum occurred in at least 1 fragment in 7 large plots, 8 large plots was the corresponding number for L. clavatum. The results showed a significant positive effect of habitat size on the occurrence of both species and a significant positive effect of connectivity on the occurrence of Lycopodium clavatum. Area protection, habitat amount and fragmentation had no observed effect on the occurrence of these species, and no fragmentation threshold or extinction threshold was found. These results indicate the importance of preserving large forest fragments with high connectivity, to assure continued viability of the examined species.

The world-wide intensification of agriculture has led to a decline in species richness due to land use change, isolation, and fragmentation of natural and semi-natural habitats in agricultural and forestry landscapes. As a consequence, there is a current landscape management focus on the importance of green infrastructure to mitigate biodiversity decline and preserve ecosystem functions e.g. pollination services and pest control. Even though intensification in agriculture has been ongoing for several hundreds of years, remnant habitats from earlier management practices may still be remaining with a surprisingly high plant richness. Preserving these habitats could help conserving plant species richness in agricultural landscapes, as well as other organisms that are dependent on plants for food and shelter. In this thesis I focus on two small remnant habitats; midfield islets and borders between managed forest and crop field in southeastern Sweden. In the past, both habitats were included in the grazing system and therefore often still have remnant population of grassland specialist species left today. I have used these two remnant habitats as model habitats to investigate the effect of landscape factors and local factors on species richness of plants, flower morphologies and plants with fleshy fruits. Additively, I analysed the effect of surrounding landscape and local openness on the functions; pollination success, biological pest control of aphids and seed predation on midfield islets. One of my studies showed that spatial distribution and size of the habitat affected plant species richness. Larger habitat size and higher connectivity between habitats increased species richness of plants in the habitats. Openness of the habitats was shown to be an important factor to increase species richness and richness of flower morphologies, both on midfield islets and in forest borders. Even though midfield islets had the highest species and morphology richness, both habitat types are needed for habitat complementary as forest borders have more plants with fleshy fruits and a higher richness of plant species that flowers in spring/early summer. It was also shown that a more complex forest border, not just with gaps in the canopy, but also with high variation in tree stem sizes increases plant species richness in the field layer. The conclusion is that by managing small remnant habitats to remain or become more semi-open and complex in their structure, would increase species richness of plants, grassland specialist species, and flower morphologies. It would also increase some ecosystem functions as seed predation and biologic pest control of aphids are more effective close to trees. If both midfield islets and forest borders would be managed to be semi-open, the area and connectivity of semi-open habitat would increase in the agricultural landscape, which may also improve pollination success as the connectivity between populations has a possibility to increase. Grassland specialist species are clearly abundant in the small remnant habitats. As the decline of semi-natural grasslands is causing a decline in grassland specialists’ species, not only plants, I recommend that small remnant habitats are included in conservation and management plans and strategies to improve habitat availability and connectivity for grassland species in agricultural landscapes. / <p>Research funder Ekoklim. Project:4339602.</p><p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>