Spiders were sampled at Mpala Research Centre, Laikipia, Kenya by pitfall-trapping and sweep-netting from May 2001 to July 2002, at a Kenyan Long-term Exclosure Experiment. The aim was to establish species composition, checklist and examine spider responses to disturbances caused by cattle, megaherbivores (giraffe and elephants) and mesoherbivores (other ungulates) by looking at three levels of resolution, namely the overall community, guilds and individual species. This is the first controlled replicated experimental study on the effects on invertebrates (spiders) by different land uses (access by large herbivores). A total of 10,487 individuals from 132 species belonging to 30 families were recorded. The family Salticidae had the highest number of species (24), followed by Gnaphosidae (20), Araneidae and Lycosidae (15 each), Theridiidae and Thomisidae (8 each) and Zodariidae (4). Most of the other families had fewer than 4 species. Throughout the study period, species not previously sampled emerged after rainfall peaks. Exclosure treatments affected plant cover, spider diversity and total species mainly through the effects of cattle, whose presence significantly reduced relative vegetation cover. An increase in vegetation cover significantly increased the diversity, total species and species evenness of the overall spider community (total samples data set). Megaherbivores and mesoherbivores had no effects on overall spider diversity. Relative vegetation cover explained approximately 20-30% of variation in community diversity, species richness and species evenness. At the guild level of resolution, the exclosure treatments had no significant effects on diversity, species richness and species evenness of web builders, plant wanderers and ground wanderers. Plant wanderers were significantly and positively correlated with relative vegetation cover, which explained 17% of variation in their diversity. Six individual species responded strongly and in contrasting ways to the same environmental variables, indicating that this level was more sensitive to environmental changes than guilds or the overall spider community. Spider diversity, relative vegetation cover and rainfall varied at a temporal scale of months and not at a spatial scale of hundreds of metres. Only species diversity and species richness from sweep-netting samples and total species from pitfall-trapping varied significantly at a spatial scale of hundreds of metres. Ordination analysis revealed that sweep-netting samples were a better indicator of grazing impacts than pitfalltrapping or combined samples and grouped to reflect cattle grazing, non-cattle grazing and to a small extent the control treatments. Other ordination analyses showed that only samples from sweep-netting and not from pitfall-trapping, were spatially partitioned at a scale of hundreds of metres. This study concludes that the spider fauna of black cotton soil habitats is rich and useful for environmental monitoring and that monitoring of several individual species as indicator of grazing impacts in savanna could be useful and relatively easy.

Orientadores: André Victor Lucci Freitas, Cristiano Agra Iserhard / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T06:07:44Z (GMT). No. of bitstreams: 1 Carreira_JuniaYasminOliveira_M.pdf: 2189038 bytes, checksum: a01160c5b9ebcc11396288ee839bb85e (MD5) Previous issue date: 2015 / Resumo: Os padrões de sazonalidade das populações de espécies tropicais são muito variáveis e pouco compreendidos, uma vez que a sazonalidade climática de uma região nem sempre se reflete em uma flutuação sazonal dos organismos que nela habitam. Caracterizar padrões temporais como sazonalidade requer longas séries temporais para obter informações claras e robustas. Além disso, integrar diversas escalas de ocorrência dos organismos, como tempo e espaço, permite compreender os fatores associados à distribuição e diversidade biológica. Para tanto, as borboletas frugívoras são excelentes organismos modelos para estudos ecológicos, podendo ser amostradas com armadilhas atrativas, uma metodologia padronizada e comparável nas dimensões espaço-temporais. Assim, utilizamos este grupo para descrever seu padrão de variação temporal em dois estratos de uma floresta estacional do sudeste brasileiro, onde a comunidade é estruturada verticalmente, bem como para entender quais os possíveis fatores abióticos podem explicar os padrões encontrados. Em três anos de amostragem (Outubro de 2011 a Setembro de 2014), constatamos a estruturação espaço-temporal das borboletas frugívoras na Serra do Japi, Jundiaí, SP. Existe um padrão bianual da abundância e da riqueza, com os picos coincidindo com as transições entre estações climáticas, tanto para dossel quanto para sub-bosque. A diversidade é dinamicamente estável entre anos, mas com bastante variação ao longo dos meses e estações. A diversidade decai na estação seca e fria, e também é baixa em dossel e no período entre setembro-outubro em decorrência da forte dominância de uma única espécie, Memphis appias. Os dois estratos distinguem-se em qualquer escala temporal. Sub-bosque é o ambiente mais estruturado temporalmente, com composição de espécies da estação seca distinta da estação úmida, e padrões de substituição em intervalos de seis meses. Meses quentes e secos favorecem a atividade das borboletas em geral, mas não há relação da precipitação com abundância ou riqueza nem para a comunidade total, nem para cada estrato separadamente. Analisando diferentes clados das borboletas frugívoras, é possível identificar padrões sazonais em Charaxinae, Brassolini, Morphini e Satyrini, e nenhum padrão para Biblidinae e Nymphalinae. Uma vez que esses picos ocorrem em períodos distintos do ano, uma relação fraca dos fatores climáticos com a comunidade total é explicada. Relações dos clados com o clima podem elucidar melhor a relação da diversidade com fatores ambientais. Todavia, os resultados sugerem que existe um ajuste da comunidade de borboletas com períodos de rebrotamento das plantas, época de maior recurso alimentar para os imaturos, um fator biótico que pode ser tão ou mais determinante para explicar as flutuações dos insetos nas zonas tropicais. / Abstract: Seasonal patterns of tropical populations are variable and poorly understood, and the climatic seasonality of a region does not always reflect in the seasonal fluctuation of organisms. To characterize temporal patterns of species requires long-term sampling and robust data that integrate different dimensions such as time and space to understand factors correlated to biological distribution and diversity. Fruit-feeding butterflies are excellent models for ecological studies and easy to sample with standardized bait traps that allow comparisons in space-time dimensions. We used this group to describe temporal variation in two vertical strata of a seasonal forest in Southeastern Brazil, where community is vertically structured, and to understand the role of abiotic factors on observed patterns. In the three-years sampling (October-2011 and September-2014), we found a spatio-temporal structure of fruit-feeding butterflies in Serra do Japi, Jundiaí municipality, São Paulo State. There was a biannual pattern of abundance and species richness, with peaks in the climatic transitions for both canopy and understory. Diversity was dynamically stable between years, varying between months and seasons. There was a decrease of diversity in the wet-cold season, in the canopy and in the September-October period due to dominance of a single species, Memphis appias. Both strata were distinct in every temporal scale analyzed. Understory was more temporally structured, with different species compositions during wet and dry seasons, and species turnover every six months. In general, dry-warm months favored butterfly activity, but there was no relation between rainfall and abundance or richness, neither for the total community nor for separate strata. Charaxinae, Brassolini, Morphini and Satyrini had distinct seasonal abundance patterns whereas Biblidinae and Nymphalinae showed no seasonal pattern. Considering the distinct temporal variation found for these clades, a weak relation between total community and climatic factors was explained. Analyzing the relation of clades with climatic factors separately may help understanding the association of diversity and weather. However, we suggest that a change in abundance occurs with the leaf growth phase, increasing when there is more food resources for butterfly immature stages. Biotic factors, such as host-plant, may be an important driver of insect population fluctuations in the tropics / Mestrado / Ecologia / Mestra em Ecologia

In this diploma thesis current state of vegetation cover was analyzed after spring flood in 2006 on the lower section of the Sázava river. Immediately after the flood there were 38 sites with alluvial deposits identified in the floodplain. The differences in species composition and species diversity between sites with alluvial deposits and sites without deposits were analyzed. The data were collected by using phytosociological relevés in pairs i.e. - plot with an alluvial deposit and plot without. There were 86 vascular plant species recorded out of which 10 species were non-native but not invasive species and 7 species were non-native invasive species. Results of this thesis revealed that species composition and diversity of invasive species differ between plots with alluvial deposits and plots without alluvial deposits. Moreover, plots without alluvial deposits host more invasive species. Keywords: vegetation succession, river floodplain, extreme floods, species diversity, plant invasion

No description available.

Den globala biologiska mångfalden minskar på grund av kraftig mänsklig exploatering av resurser. Ett sådant exempel är diversitetens nedgång i Fennoskandias skogar. Denna studie sökte att undersöka om skogsbruket negativt påverkar mångfalden i en svensk skog i förhållande till dess vedlevande lavar och mossor, med hjälp av träsubstratets kvaliteter som jämförelse och oberoende variabel. 21 vedlevande mossor och lavar var grunden för dessa jämförelser. Studien jämförde två ursprungligen likadana produktionsskogar, där den ena blev ett naturreservat för nästan 100 år sedan. De ligger sydost om Linköping stad, nära BjärkaSäby. Tio 300 m2transekter med slumpmässigt genererade startpunkter och riktningar etablerades i varje skog. Kvantiteten av, deras diameter, deras höjd/längd och deras arttillhörighet för levande och döda träd över en meter i höjd noterades. Nedbrytningsstadier för liggande död ved bredare än 5 centimeter noterades. Ett Wilcoxon-rank-summa-test avslöjade signifikant högre medelvärden av förekomster för vedlevande arter inuti reservatet. Oparade t-tester avslöjade signifikant högre medelvärden för de vedlevande arternasarttäckning och för volymen död ved i reservatet. Pearsons chi-två test avslöjade signifikanta fördelningsskillnader hos levande tallars och lövträdsdiametrar mellan de två områdena men inte mellan fördelningen av nedbrytningsstadier eller hos diametrarna för levande granar. Logistiska regressioner avslöjade att de flesta av de vedlevande arterna med över 10 förekomster i båda områdena över lag hade åtminstone en signifikant korrelation med dess substrats egenskaper. Fynden tyder på att modernt skogsbruk påverkar vedlevande arter negativt, främst på grund av den lilla mängden substrat tillgängligt i produktionsskogen snarare än på grund av substratens variation av egenskaper. / Global biodiversity is declining due to human exploitation, such as seen with its decline within Fennoscandian forests. This study aimed to see if forestry negatively impacts diversity in a Swedish forest in relation to its wood-living lichens and mosses, using the wooden substrate qualities as a point of comparison. 21 saproxylic mosses and lichens formed the basis of these comparisons. The study compared two originally equal production forests, where one became a reserve almost 100 years ago. They are located south-east of Linköping City, near Bjärka-Säby. Ten 300 m2 transects with randomly generated placements and directions were established in each forest. The quantity, diameter, height/length, and species of living and deadtrees over one meter tall were noted. Decay stages for lying dead wood broader than 5 centimeters was noted. A Wilcoxon-rank-sum-test revealed significantly higher meanoccurrences of saproxylic species in the reserve. Unpaired t-tests revealed significantly higher means of saproxylic species coverage and volume of dead wood in the reserve. Pearson’s chi-square test revealed significant distribution differences of living pines and deciduous tree diameters between the two areas but not in the distribution of wood decay stages or in the diameters of living spruces. Logistic regressions revealed that most of the saproxylic specieswith over 10 occurrences in both areas over all had at least one significant correlation with its substrate’s properties. Findings indicate that modern forestry negatively impacts wood-dwelling species mostly due to the small amount of substrate in the managed forest rather than due to their variety

Three different habitats: secondary forest, acacia plantation, and mixed forests on limestone, were chosen to determine and compare the ant species diversity in these habitats. A total of 24 identified species and 11 morphology species belonging to 20 genera in seven subfamilies were collected using pitfall traps from June 2014 to May 2015. The Shannon-Wiener’s species diversity index indicated that the diversity was the highest in the acacia plantation (2.08), followed by the secondary forest (1.99) and lowest in the mixed forests on limestone (1.83). There are three dominant species in the habitat (I), Pheidole noda, Odontomachus cf. monticola, and Odontoponera denticulate; four dominant species in the habitat (II), Odontoponera denticulata, Carebara diversa, Technomyrmex brunneus and Anoplolepis gracilipes; and only one dominant species in the habitat (III), Anoplolepis gracilipes. The species similarity (S) relatively low may be because of the difference vegetation and condition in the three habitats. / Đa dạng loài kiến trong ba môi trường sống khác nhau: rừng rậm thường xanh nhiệt đới, rừng keo và rừng hỗn giao trên núi đá vôi, được nghiên cứu để xác định và so sánh sự đa dạng các loài kiến trong những môi trường sống. Phương pháp nghiên cứu: sử dụng bẫy hố từ tháng 6 năm 2014 đến tháng 5 năm 2015. Đã ghi nhận được 35 loài, thuộc 20 giống, 7 phân họ. Chỉ số đa dạng loài Shannon-Wiener cho thấy rừng keo có chỉ số đa dạng cao nhất (2,08), tiếp theo là rừng rậm thường xanh nhiệt đới (1,99) và cuối cùng là rừng hỗn giao trên núi đá vôi (1,83). Có 3 loài ưu thế ở sinh cảnh (I) là Pheidole noda, Odontomachus cf. monticola và Odontoponera denticulata, bốn loài ưu thế ở sinh cảnh (II) là Carebara diversa, Technomyrmex brunneus, Odontoponera denticulate và Anoplolepis gracilipes. Ở sinh cảnh (III) chỉ có duy nhất một loài chiếm ưu thế là loài Anoplolepis gracilipes. Chỉ số tương đồng (S) tương đối thấp có thể là do sự khác nhau ở các thảm thực vật và điều kiện sống trong ba sinh cảnh.

Understanding relationships between large herbivores and plant species diversity in dynamic riparian zones, and more specifically sodic zones, is critical to biodiversity conservation. Sodic patches form an integral part of savanna ecosystems because of the ecosystem services and functions they provide, i.e. accumulation of nutrients, provision of open spaces for predator vigilance and formation of wet season wallowing points. Furthermore, these key resource areas sustain body condition for dry season survival and support reproduction through nutritional benefits, making them „nutrient hotspots.‟ The Nkuhlu research exclosures in the Kruger National Park (KNP) provide a unique opportunity to investigate spatial and temporal heterogeneity patterns within riparian zones, and how these patterns are affected by fire and herbivory. A monitoring project was initiated to answer questions pertaining to the dynamics of the herbaceous layer and was aimed at determining (a) whether there exists meaningful variance in herbaceous plant species richness and diversity across different treatments of fire and herbivory in the ecologically sensitive sodic zone, (b) if temporal shifts in plant species composition and diversity occurs, (c) whether an increase in herbaceous biomass, an artifact of herbivory and fire exclusion, suppresses herbaceous plant species diversity and richness, and (d) whether there exists a significant relationship between herbaceous biomass and species richness/diversity. The Nkuhlu exclosures consist of three herbivory treatments, each divided into a fire and no-fire treatment, hence six treatment combinations overall. Herbivory treatments consisted of, (1) a partially fenced area designed to specifically exclude elephants (giraffes are also excluded due to body size), (2) an open, unfenced area and (3) a fully fenced area, designed to exclude all herbivores larger than a hare. Herbaceous vegetation was sampled in two 1 m2 circular sub-plots in the eastern and western corners of each of the 82 fixed plots. Biomass of each plot was estimated with a Disc Pasture Meter (DPM) by sampling ten points diagonally within each plot. DPM-readings were converted to kg/ha according to latest conversions for the Lowveld Savanna. Species richness and biomass showed significant variance across treatments for the 2010 dataset, whereas no significant variation in herbaceous species diversity was perceived. Combined treatment of fire absence and herbivore presence contributed to higher forb species richness in the sodic zone. Biomass was significantly higher in fully fenced areas where herbivores were excluded, opposed to the open and partially fenced areas. Although no significant variation was recorded for diversity across treatments, lowest diversity was recorded in the absence of all herbivores, especially in combination with fire treatment. After nine years of herbivory exclusion, diversity of herbaceous species varied significantly. Herbaceous species composition changed over time in areas exposed to herbivory, while composition of fully fenced treatments did not reveal change. A hump-shaped relationship exists between herbaceous species richness/diversity and field biomass, at least for areas with biomass levels not exceeding 2500 kg/ha. Herbivores are therefore considered essential in sustaining herbaceous plant species richness and system heterogeneity in the sodic zone, since herbaceous species richness/diversity was higher in herbivore presence and herbaceous species composition changed over time in areas exposed to herbivory. Although statistically non-significant, fire seems to suppress species richness. Conservation implications: This study could be used as framework to advance and develop sciencebased management strategies for, at least, the sodic zones of the KNP. Research in these exclosures contributes to our understanding of these landscapes and benefit ecosystem conservation planning. It also provides valuable long-term data for key ecological processes. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014

Understanding relationships between large herbivores and plant species diversity in dynamic riparian zones, and more specifically sodic zones, is critical to biodiversity conservation. Sodic patches form an integral part of savanna ecosystems because of the ecosystem services and functions they provide, i.e. accumulation of nutrients, provision of open spaces for predator vigilance and formation of wet season wallowing points. Furthermore, these key resource areas sustain body condition for dry season survival and support reproduction through nutritional benefits, making them „nutrient hotspots.‟ The Nkuhlu research exclosures in the Kruger National Park (KNP) provide a unique opportunity to investigate spatial and temporal heterogeneity patterns within riparian zones, and how these patterns are affected by fire and herbivory. A monitoring project was initiated to answer questions pertaining to the dynamics of the herbaceous layer and was aimed at determining (a) whether there exists meaningful variance in herbaceous plant species richness and diversity across different treatments of fire and herbivory in the ecologically sensitive sodic zone, (b) if temporal shifts in plant species composition and diversity occurs, (c) whether an increase in herbaceous biomass, an artifact of herbivory and fire exclusion, suppresses herbaceous plant species diversity and richness, and (d) whether there exists a significant relationship between herbaceous biomass and species richness/diversity. The Nkuhlu exclosures consist of three herbivory treatments, each divided into a fire and no-fire treatment, hence six treatment combinations overall. Herbivory treatments consisted of, (1) a partially fenced area designed to specifically exclude elephants (giraffes are also excluded due to body size), (2) an open, unfenced area and (3) a fully fenced area, designed to exclude all herbivores larger than a hare. Herbaceous vegetation was sampled in two 1 m2 circular sub-plots in the eastern and western corners of each of the 82 fixed plots. Biomass of each plot was estimated with a Disc Pasture Meter (DPM) by sampling ten points diagonally within each plot. DPM-readings were converted to kg/ha according to latest conversions for the Lowveld Savanna. Species richness and biomass showed significant variance across treatments for the 2010 dataset, whereas no significant variation in herbaceous species diversity was perceived. Combined treatment of fire absence and herbivore presence contributed to higher forb species richness in the sodic zone. Biomass was significantly higher in fully fenced areas where herbivores were excluded, opposed to the open and partially fenced areas. Although no significant variation was recorded for diversity across treatments, lowest diversity was recorded in the absence of all herbivores, especially in combination with fire treatment. After nine years of herbivory exclusion, diversity of herbaceous species varied significantly. Herbaceous species composition changed over time in areas exposed to herbivory, while composition of fully fenced treatments did not reveal change. A hump-shaped relationship exists between herbaceous species richness/diversity and field biomass, at least for areas with biomass levels not exceeding 2500 kg/ha. Herbivores are therefore considered essential in sustaining herbaceous plant species richness and system heterogeneity in the sodic zone, since herbaceous species richness/diversity was higher in herbivore presence and herbaceous species composition changed over time in areas exposed to herbivory. Although statistically non-significant, fire seems to suppress species richness. Conservation implications: This study could be used as framework to advance and develop sciencebased management strategies for, at least, the sodic zones of the KNP. Research in these exclosures contributes to our understanding of these landscapes and benefit ecosystem conservation planning. It also provides valuable long-term data for key ecological processes. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014

Future global change scenarios predict a dramatic loss of biodiversity for many regions in the world, potentially reducing the resistance and resilience of ecosystem functions. Once before, during Plio-Pleistocene glaciations, harsher climatic conditions in Europe as compared to North America led to a more depauperate tree flora. Here we hypothesize that this climate driven species loss has also reduced functional diversity in Europe as compared to North America. We used variation in 26 traits for 154 North American and 66 European tree species and grid-based co-occurrences derived from distribution maps to compare functional diversity patterns of the two continents. First, we identified similar regions with respect to contemporary climate in the temperate zone of North America and Europe. Second, we compared the functional diversity of both continents and for the climatically similar subregions using the functional dispersion-index (FDis) and the functional richness index (FRic). Third, we accounted in these comparisons for grid-scale differences in species richness, and, fourth, investigated the associated trait spaces using dimensionality reduction. For gymnosperms we find similar functional diversity on both continents, whereas for angiosperms functional diversity is significantly greater in Europe than in North America. These results are consistent across different scales, for climatically similar regions and considering species richness patterns. We decomposed these differences in trait space occupation into differences in functional diversity vs. differences in functional identity. We show that climate-driven species loss on a continental scale might be decoupled from or at least not linearly related to changes in functional diversity. This might be important when analyzing the effects of climate-driven biodiversity change on ecosystem functioning.

Thesis (MScConsEcol (Conservation Ecology and Entomology)--University of Stellenbosch, 2007. / Understanding the drivers and mechanisms of changes in plant richness is a basis for making scientifically sound ecological predictions and land use decisions. Of the numerous factors affecting plant richness, soil has a particularly large influence on the composition and structure of terrestrial flora. Infiltrability is one of the most important factors determining soil moisture, and therefore is of particular interest in semi-arid ecosystems, where water is one of the most limiting resources. Other soil properties, such as clay + silt content, electrical conductivity (EC) and pH may also influence plants. Heterogeneity of these properties creates niches with specific conditions, which in turn affects spatial distribution of plants. An understanding of the relationships between plant richness and soil properties is, however, incomplete. The present study has two main foci. Firstly, relationships between plant richness and soil infiltrability, clay + silt, EC and pH (H2O) were investigated, and secondly, due to the strong influence of infiltrability on plant richness, further investigations were undertaken to improve the understanding of the role of particle size fractions, EC of the soil solution and exchangeable sodium percentage (ESP) on infiltrability. This study only concentrated on the surface 2 cm thick soil layer (known as pedoderm).