Boreal forests in Europe are intensively managed for timber and pulp production, resulting in decreased biodiversity, and in the long-term leading to a reduced number of functioning ecosystem services. To develop a more sustainable forest management it is important to investigate what features and habitat types are needed to preserve a high diversity of species within the forestry landscapes. Birds are a suitable study taxon since their ecology is well known and their diversity often mirrors the diversity of other taxa. This study investigated how different habitat types, for example, forest stand composition and age of forest etc., influence the diversity, species richness and abundance of forest bird species in boreal forestry landscapes in Sweden. I expected that the percentage of deciduous forests and older forests would increase the diversity and richness of forest birds, while spruce forests and young forests would have negative effects. Further, I expected mixed forest stands to be more diverse regarding forest birds than pure forest stands. The sites for this study consisted of fiveforestry landscapes in south Sweden, with both active forestry and multifunctional forestry areas. The results showed positive effects of the percentage of deciduous forests, wetlands, older forests, mixed coniferous forests, and pine forests on species richness, abundance, and diversity of forest bird species. However, deciduous forests and older forests had the strongestpositive influence on species richness and diversity. Furthermore, I did not find evidence that mixed forest stands have a higher diversity or species richness than monocultures of only spruce and pine respectively.

No description available.

To develop effective conservation planning and mitigate biodiversity loss, standardized metrics for monitoring and assessing biodiversity are needed. This information is particularly vital in Botswana, where knowledge of many of the diverse wildlife populations is lacking. To address this knowledge gap, my dissertation research evaluated the distributions, densities, and ecology of the wildlife community in northern Botswana, with a focus on terrestrial carnivore species given their importance both ecologically and economically. My objectives were threefold: 1) estimate the distributions of the mammal community (n = 44 species) and evaluate community, group, and species-specific responses to anthropogenic and environmental variables, 2) test whether the presence of intraguild species or resource availability had a larger influence on the seasonal distributions of carnivore species, and 3) simultaneously estimate the population densities of 7 carnivore species. To accomplish these objectives, I completed a multi-year camera trap survey in a 1,154-km2 study area and analyzed the data using occupancy models (single and multi- species) and spatially explicit capture-recapture models. Estimates of species richness ranged from 8 to 27 unique species, species had a mean occurrence probability of 0.32 (95% credible interval = 0.21–0.45), and estimated densities ranged from 1.8 aardwolves (Proteles cristata) to 12.7 spotted hyenas (Crocuta crocuta) per 100 km2. The occupancy and richness of terrestrial mammals was negatively associated with human disturbance and in general, positively associated with open grasslands/floodplains. Carnivore species, specifically, tended to have greater species richness and larger population densities in open habitats than in closed. I also found carnivore distributions were positively associated with the detection rate of intraguild competitors and predators, suggesting competitor/predator avoidance did not play a large role in shaping carnivore community structure. My research highlights the pivotal role protected areas and grasslands play in conserving wildlife populations in northern Botswana. Additionally, my research helps progress camera trap analyses from single to multi-species assessments. Broader application of this multi-species approach would likely result in a better understanding of wildlife and carnivore communities which in turn, may help inform management actions aimed at addressing the loss of wildlife populations globally. / Ph. D.

Invasions of non-native species cause problems in ecosystems worldwide, and despite the extensive effort that has been put into research about invasions, we still lack a good understanding for why some, but not other, communities resist these invasions. In this doctoral thesis I test hypotheses on biotic resistance using a large dataset of more than 1000 both failed and successful introductions of freshwater fish into Swedish lakes. We have found that the classic species richness hypothesis is a poor descriptor of introduction success because it fails to acknowledge that resident species contribute to the resistance in different ways. We developed a new measure of biotic resistance, the weighted species richness, which takes into account that the resident species contributes to the resistance with different strength and sign. Further, we correlated performance traits of species in their role as an invader and as a resident species to predict how the biotic resistance of these communities would develop over time. We found a positive correlation between performance traits: Some species have high introduction success, they make a large contribution to the resistance, and they cause extinctions when introduced but do not go extinct themselves when other species establishes, whereas other species are weak performers in these respects. Thus, the biotic resistance of these communities should grow stronger as non-native species accumulates. These results give us clues about what type of communities that should be most sensitive to further invasions, i.e., communities harboring species weak performers.  My results show that the biotic resistance of communities is an important factor in determining invasibility of a community. They also show that methods for quantifying resistance must take into account how interactions are structured in nature. What determine the biotic resistance of a community is the type of interactions that the resident species have with the invader and not the species richness of the community.

Biological diversity is controlled by an array of factors and processes all active at different spatial and temporal scales. Regional factors control what species are available to occur locally, whereas the local factors determine what species are actually capable of colonizing the locality. I have investigated how these local and regional factors affect species richness and diversity, mainly of fish in Swedish lakes and in order to assess the impact of dispersal mode one study on bacteria was also performed. In addition, potential first steps towards speciation were investigated in perch (Perca fluviatilis) from two different habitats. Fish species richness and diversity were found to be regulated by history, dispersal limitation and the local environment. In addition, striking similarities were found in the control of community composition for fish and bacteria. Both were regulated by nearly equal parts regional and local factors. The study of morphological and genetical variation in perch (Perca fluviatilis) revealed genetic differentiation at small spatial scales, suggesting that genetic differences can evolve between groups at strikingly small spatial scales, which might have implications for speciation in a long time perspective. Based on these findings I conclude that space and time matter. Space has the potential to isolate sites. And both dispersal and local extinctions, it seems, might take a long time, as effects of the last ice-age can still be seen on the contemporary fish community richness and composition.

A major goal of evolutionary biology and ecology is to understand why species richness varies among clades. Previous studies have suggested that variation in richness among clades might be related to variation in rates of morphological evolution among clades (e.g., body size and shape). Other studies have suggested that richness patterns might be related to variation in rates of climatic-niche evolution. However, few studies, if any, have tested the relative importance of these variables in explaining patterns of richness among clades. Here, we test their relative importance among major clades of Plethodontidae, the most species-rich family of salamanders. Earlier studies have suggested that climatic-niche evolution explains patterns of diversification among plethodontid clades, whereas rates of morphological evolution do not. A subsequent study stated that rates of morphological evolution instead explained patterns of species richness among plethodontid clades (along with "ecological limits" on richness of clades, leading to saturation of clades with species, given limited resources). However, they did not consider climatic-niche evolution. Using phylogenetic multiple regression, we show that rates of climatic-niche evolution explain most variation in richness among plethodontid clades, whereas rates of morphological evolution do not. We find little evidence that ecological limits explain patterns of richness among plethodontid clades. We also test whether rates of morphological and climatic-niche evolution are correlated, and find that they are not. Overall, our results help explain richness patterns in a major amphibian group and provide possibly the first test of the relative importance of climatic niches and morphological evolution in explaining diversity patterns.

Land-use history has been recognized as an important factor in shaping biological communities in clear-cuts. Many solitary bees and flower beetles (Cerambycidae: Lepturinae) are commonly found in clear-cuts, which serve as early successional habitats. I analyzed the effect of land-use history on the abundance and species richness, as well as the preference for land-use history in specific species, of solitary bees and flower beetles in coniferous clear-cuts in southern Sweden. Additionally, the effect of site-specific environmental factors was examined. Insects were caught with blue, white and yellow pan-traps in 48 clear-cuts, of which half were meadow and half were forest in the 1870s. With few exceptions, the species found did not show preference for any land-use history. Furthermore, land-use history had no significant effect on the abundance or species richness of solitary bees or flower beetles. This may be due to pan-traps being less attractive in flower-rich locations, a bias in the sampling method. However, species richness and abundance of solitary bees was higher in young clear-cuts (2-4 years old), probably best explained by more exposed soil and higher frequencies of flowering plants in newer clear-cuts. Abundance of flower beetles was higher in old clear-cuts (6-8 years old). This may be due to larger amounts of more strongly decomposed wood in older clear-cuts, which is used in the flower beetles´ larval development. I conclude that solitary bees are likely to benefit if clear-cuts, particularly with meadow history, are kept more open by introducing disturbance regimes, as suggested by previous studies.

No description available.

New farming needs and innovations have, over time, led to changes in land use. Arable fields have been turned into pastures and semi-natural pastures into arable fields. Due to the ecological value of continually grazed semi-natural pastures in Sweden the aim of this study is to find out how former arable fields that are permanently grazed differ from semi-natural pastures. In this study I selected appropriate semi-natural pastures from a national monitoring program on seminatural- pastures and meadows. Plots continuously grazed were compared with grazed plots on former arable fields. Pair-wise differences in the Ellenberg indicator values Light (L), Soil moisture (F), soil pH (R) and soil nitrogen (N), vertical coverage of trees, bushes and vegetation, species richness and species composition were tested. Except for species composition there were only small differences between former arable fields that are permanently grazed and semi-natural pastures. That means former arable fields can with time and grazing gain many of the values continuously grazed semi-natural pastures have.

Objetivou-se caracterizar a composição florística e fitossociológica do componente arbustivo-arbóreo de quatro quintais agroflorestais (QAs) no reassentamento Mariana, Tocantins, a fim de conhecer a estrutura dessas áreas e as suas contribuições para a manutenção, proteção e conservação da biodiversidade. Além disso, buscou-se subsidiar a formação de uma base de dados referentes aos quintais agroflorestais no estado do Tocantins. O levantamento foi realizado em quatro quintais agroflorestais no reassentamento Mariana, que se encontra entre os municípios de Palmas e Porto Nacional, no estado do Tocantins. Foram instaladas três parcelas de 20x30m em cada quintal, perfazendo um total de 0,72 ha de área amostral, sendo amostrados todos os indivíduos arbustivo-arbóreos com circunferência altura do peito 1,30 cm do solo (CAP) ≥ a 10 cm. Foram amostrados nos quatro QAs um total de 477 indivíduos, 81 espécies, 34 famílias e 73 gêneros. O valor encontrado para o índice de diversidade (Shannon) foi de 3,68 e para equabilidade (Pielou) foi de 0,83, valores esses encontrados em 0,72 ha de área amostral. Individualmente, os quintais agroflorestais apresentaram os seguintes valores de diversidade de Shannon (H’) QA1 2,52; QA2 3,27; QA3 2,66 e QA4 2,94; e equabilidade de Pielou (J’) QA1 0,78; QA2 0,90; QA3 0,77 e QA4 0,85. A altura média da vegetação no QA1 foi de 4,79m e área basal total de 120,17m²/ha, no QA2 a altura media foi de 5,14m com área basal total de 18,49m²/ha, no QA3 a altura media foi de 3,66m e área basal total de 27,42m²/ha, no QA4 a altura media foi de 5,54m com área basal total de 33,98m²/ha. As dez espécies mais importantes dos quintais agroflorestais representaram juntas 44,26% do valor de importância total, com destaque para as espécies Malpighia glabra, Psidium guajava e Mangifera indica que alcançaram posições de destaque em mais de um quintal. As dez famílias mais importantes somaram juntas 67,63% do IVI total as famílias que mais se destacaram foram Arecaceae, Anacardiaceae e Fabaceae para todos os (QAs) avaliados. Assim, pode-se inferir que os quintais agroflorestais do reassentamento Mariana demonstraram alta riqueza e diversidade, evidenciando grande heterogeneidade ambiental e baixa dominância ecológica. / The objective of this study was to characterize the floristic and phytosociological composition of the shrubby-arboreal component of four quintals agroforestry (QAs) in the Mariana resettlement, Tocantins, in order to know the structure of these areas and their contributions to the maintenance, protection and conservation of biodiversity. In addition, it was sought to subsidize the formation of a database of agroforestry quintals in the state of Tocantins. Three 20x30m plots were installed in each quintal, making a total of 0,72 ha of sample area, and all shrub-arboreal individuals with chest height circumference 1,30 cm (CAP) ≥ 10 cm were sampled. A total of 477 individuals, 81 species, 34 families and 73 genera were sampled in the four QAs. The value found for the diversity index (Shannon) was 3,68 and for equability (Pielou) was 0,83, values found in 0,72 ha of sample area.Individually, agroforestry quintals had the following Shannon diversity values (H '): QA1 2,52; QA2 3,27; QA3 2,66 and QA4 2,94; And Pielou equability (J ') QA1 0,78; QA2 0,90; QA3 0,77 and QA 40,85. The average height of the vegetation in QA 01 was 4,79m and total basal area was 120,17 m²/ ha, in QA 02 the average height was 5,14m with a total basal area of 18,49 m²/ ha, in QA 03 a mean height was 3,66 m and total basal area was 27,42 m²/ ha; in QA 04 the mean height was 5,54m with a total basal area of 33,98 m²/ha.The ten most important agroforestry species together represented 44.26% of the value of total importance, especially the species: Malpighia glabra, Psidium guajava and Mangifera indica that they reached prominent positions in more than one quintal.The ten most important families together accounted for 67.63% of the total IVI, and the families that stood out were Arecaceae, Anacardiaceae and Fabaceae for all (QAs) evaluated. Thus, it can be inferred that the agroforestry quintals of the Mariana resettlement demonstrated high richness and diversity, evidencing great environmental heterogeneity and low ecological dominance.