TY - JOUR A1 - Isaacs, Darren A1 - Mikasi, Sello Given A1 - Obasa, Adetayo Emmanuel A1 - Ikomey, George Mondinde A1 - Shityakov, Sergey A1 - Cloete, Ruben A1 - Jacobs, Graeme Brendon T1 - Structural comparison of diverse HIV-1 subtypes using molecular modelling and docking analyses of integrase inhibitors JF - Viruses N2 - The process of viral integration into the host genome is an essential step of the HIV-1 life cycle. The viral integrase (IN) enzyme catalyzes integration. IN is an ideal therapeutic enzyme targeted by several drugs; raltegravir (RAL), elvitegravir (EVG), dolutegravir (DTG), and bictegravir (BIC) having been approved by the USA Food and Drug Administration (FDA). Due to high HIV-1 diversity, it is not well understood how specific naturally occurring polymorphisms (NOPs) in IN may affect the structure/function and binding affinity of integrase strand transfer inhibitors (INSTIs). We applied computational methods of molecular modelling and docking to analyze the effect of NOPs on the full-length IN structure and INSTI binding. We identified 13 NOPs within the Cameroonian-derived CRF02_AG IN sequences and further identified 17 NOPs within HIV-1C South African sequences. The NOPs in the IN structures did not show any differences in INSTI binding affinity. However, linear regression analysis revealed a positive correlation between the Ki and EC50 values for DTG and BIC as strong inhibitors of HIV-1 IN subtypes. All INSTIs are clinically effective against diverse HIV-1 strains from INSTI treatment-naïve populations. This study supports the use of second-generation INSTIs such as DTG and BIC as part of first-line combination antiretroviral therapy (cART) regimens, due to a stronger genetic barrier to the emergence of drug resistance. KW - integrase KW - naturally occurring polymorphisms KW - HIV-1 KW - molecular modelling KW - molecular docking KW - diversity Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-211170 SN - 1999-4915 VL - 12 IS - 9 ER - TY - JOUR A1 - Hornick, Thomas A1 - Richter, Anett A1 - Harpole, William Stanley A1 - Bastl, Maximilian A1 - Bohlmann, Stephanie A1 - Bonn, Aletta A1 - Bumberger, Jan A1 - Dietrich, Peter A1 - Gemeinholzer, Birgit A1 - Grote, Rüdiger A1 - Heinold, Bernd A1 - Keller, Alexander A1 - Luttkus, Marie L. A1 - Mäder, Patrick A1 - Motivans Švara, Elena A1 - Passonneau, Sarah A1 - Punyasena, Surangi W. A1 - Rakosy, Demetra A1 - Richter, Ronny A1 - Sickel, Wiebke A1 - Steffan‐Dewenter, Ingolf A1 - Theodorou, Panagiotis A1 - Treudler, Regina A1 - Werchan, Barbora A1 - Werchan, Matthias A1 - Wolke, Ralf A1 - Dunker, Susanne T1 - An integrative environmental pollen diversity assessment and its importance for the Sustainable Development Goals JF - Plants, People, Planet N2 - Societal Impact Statement Pollen relates to many aspects of human and environmental health, which protection and improvement are endorsed by the United Nations Sustainable Development Goals. By highlighting these connections in the frame of current challenges in monitoring and research, we discuss the need of more integrative and multidisciplinary pollen research related to societal needs, improving health of humans and our ecosystems for a sustainable future. Summary Pollen is at once intimately part of the reproductive cycle of seed plants and simultaneously highly relevant for the environment (pollinators, vector for nutrients, or organisms), people (food safety and health), and climate (cloud condensation nuclei and climate reconstruction). We provide an interdisciplinary perspective on the many and connected roles of pollen to foster a better integration of the currently disparate fields of pollen research, which would benefit from the sharing of general knowledge, technical advancements, or data processing solutions. We propose a more interdisciplinary and holistic research approach that encompasses total environmental pollen diversity (ePD) (wind and animal and occasionally water distributed pollen) at multiple levels of diversity (genotypic, phenotypic, physiological, chemical, and functional) across space and time. This interdisciplinary approach holds the potential to contribute to pressing human issues, including addressing United Nations Sustainable Development Goals, fostering social and political awareness of these tiny yet important and fascinating particles. KW - aerobiology KW - allergy KW - diversity KW - environmental monitoring KW - food safety KW - paleoecology KW - palynology KW - pollination Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-276487 VL - 4 IS - 2 SP - 110 EP - 121 ER - TY - JOUR A1 - Tolay, Nazife A1 - Buchberger, Alexander T1 - Comparative profiling of stress granule clearance reveals differential contributions of the ubiquitin system JF - Life Science Alliance N2 - Stress granules (SGs) are cytoplasmic condensates containing untranslated mRNP complexes. They are induced by various proteotoxic conditions such as heat, oxidative, and osmotic stress. SGs are believed to protect mRNPs from degradation and to enable cells to rapidly resume translation when stress conditions subside. SG dynamics are controlled by various posttranslationalmodifications, but the role of the ubiquitin system has remained controversial. Here, we present a comparative analysis addressing the involvement of the ubiquitin system in SG clearance. Using high-resolution immuno-fluorescence microscopy, we found that ubiquitin associated to varying extent with SGs induced by heat, arsenite, H2O2, sorbitol, or combined puromycin and Hsp70 inhibitor treatment. SG-associated ubiquitin species included K48- and K63-linked conjugates, whereas free ubiquitin was not significantly enriched. Inhibition of the ubiquitin activating enzyme, deubiquitylating enzymes, the 26S proteasome and p97/VCP impaired the clearance of arsenite- and heat-induced SGs, whereas SGs induced by other stress conditions were little affected. Our data underline the differential involvement of the ubiquitin system in SG clearance, a process important to prevent the formation of disease-linked aberrant SGs. KW - phase transition KW - quality control KW - protein KW - inhibition KW - complexity KW - separation KW - diversity KW - autophagy KW - ALS KW - P97 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259810 VL - 4 IS - 5 ER - TY - JOUR A1 - Stiegler, Jonas A1 - von Hoermann, Christian A1 - Müller, Jörg A1 - Benbow, M. Eric A1 - Heurich, Marco T1 - Carcass provisioning for scavenger conservation in a temperate forest ecosystem JF - Ecosphere N2 - Carrion plays an essential role in shaping the structure and functioning of ecosystems and has far‐reaching implications for biodiversity conservation. The change in availability and type of carcasses throughout ecosystems can involve negative effects for scavenging communities. To address this issue, there have been recent conservation management measures of carrion provision in natural systems. However, the optimal conditions under which exposing carcasses to optimize conservation outcomes are still limited. Here, we used camera traps throughout elevational and vegetational gradients to monitor the consumption of 48 deer carcasses over a study period of six years by evaluating 270,279 photographs resulting out of 15,373 trap nights. We detected 17 species visiting carcass deployments, including five endangered species. Our results show that large carcasses, the winter season, and a heterogeneous surrounding habitat enhanced the frequency of carcass visits and the species richness of scavenger assemblages. Contrary to our expectations, carcass species, condition (fresh/frozen), and provision schedule (continuous vs single exposure) did not influence scavenging frequency or diversity. The carcass visitation frequency increased with carcass mass and lower temperatures. The effect of large carcasses was especially pronounced for mesopredators and the Eurasian lynx (Lynx lynx). Lynx were not too influenced in its carrion acquisition by the season, but exclusively preferred remote habitats containing higher forest cover. Birds of prey, mesopredators, and top predators were also positively influenced by the visiting rate of ravens (Corvus corax), whereas no biotic or abiotic preferences were found for wild boars (Sus scrofa). This study provides evidence that any ungulate species of carrion, either in a fresh or in previously frozen condition, attracts a high diversity of scavengers especially during winter, thereby supporting earlier work that carcass provisions may support scavenger communities and endangered species. KW - anthropogenic food subsidies KW - carrion ecology KW - diversity KW - nature conservation KW - necrobiome KW - vertebrate scavenger KW - wildlife management Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-218054 VL - 11 IS - 4 ER - TY - JOUR A1 - Thorn, Simon A1 - Chao, Anne A1 - Georgiev, Konstadin B. A1 - Müller, Jörg A1 - Bässler, Claus A1 - Campbell, John L. A1 - Jorge, Castro A1 - Chen, Yan-Han A1 - Choi, Chang-Yong A1 - Cobb, Tyler P. A1 - Donato, Daniel C. A1 - Durska, Ewa A1 - Macdonald, Ellen A1 - Feldhaar, Heike A1 - Fontaine, Jospeh B. A1 - Fornwalt, Paula J. A1 - Hernández Hernández, Raquel María A1 - Hutto, Richard L. A1 - Koivula, Matti A1 - Lee, Eun-Jae A1 - Lindenmayer, David A1 - Mikusinski, Grzegorz A1 - Obrist, Martin K. A1 - Perlík, Michal A1 - Rost, Josep A1 - Waldron, Kaysandra A1 - Wermelinger, Beat A1 - Weiß, Ingmar A1 - Zmihorski, Michal A1 - Leverkus, Alexandro B. T1 - Estimating retention benchmarks for salvage logging to protect biodiversity JF - Nature Communications N2 - Forests are increasingly affected by natural disturbances. Subsequent salvage logging, a widespread management practice conducted predominantly to recover economic capital, produces further disturbance and impacts biodiversity worldwide. Hence, naturally disturbed forests are among the most threatened habitats in the world, with consequences for their associated biodiversity. However, there are no evidence-based benchmarks for the proportion of area of naturally disturbed forests to be excluded from salvage logging to conserve biodiversity. We apply a mixed rarefaction/extrapolation approach to a global multi-taxa dataset from disturbed forests, including birds, plants, insects and fungi, to close this gap. We find that 757% (mean +/- SD) of a naturally disturbed area of a forest needs to be left unlogged to maintain 90% richness of its unique species, whereas retaining 50% of a naturally disturbed forest unlogged maintains 73 +/- 12% of its unique species richness. These values do not change with the time elapsed since disturbance but vary considerably among taxonomic groups. Salvage logging has become a common practice to gain economic returns from naturally disturbed forests, but it could have considerable negative effects on biodiversity. Here the authors use a recently developed statistical method to estimate that ca. 75% of the naturally disturbed forest should be left unlogged to maintain 90% of the species unique to the area. KW - natural disturbance KW - bird communities KW - forest KW - management KW - beetle KW - conservation KW - windthrow KW - diversity KW - impact KW - fire Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230512 VL - 11 ER - TY - JOUR A1 - Gottschlich, Günter T1 - Synopse der für Deutschland nachgewiesenen Arten und Unterarten der Gattung Hieracium s. l. (Hieracium s. str. und Pilosella), aufgeschlüsselt nach Vorkommen in den einzelnen Bundesländern T1 - Synopsis of all species and subspecies of the genus Hieracium s. l. (Hieracium s. str. and Pilosella) in Germany according to the records cited in literature for the German federal states JF - Forum geobotanicum N2 - Eine Liste der 205 Arten und 1561 Unterarten der Gattung Hieracium s. l. , die in Deutschland, aufgeschlüsselt nach Bundesländern vorkommen, wird vorgestellt. Da die meisten infraspezifischen Namen unter Hieracium publiziert wurden und um die Zahl der invaliden Namen unter Pilosella in der Liste zu minimieren, wird auf eine Aufteilung in Hieracium und Pilosella verzichtet. Durch Farbmarkierungen wird gekennzeichnet, welche Unterart ursprünglich aus einem Bundesland beschrieben wurde bzw. ob ein Syntypus aus einem Bundesland stammt. N2 - A list of 205 collective species and 1563 subspecies of the genus Hieracium s. l. detected for Germany and its federal states, is provided. As the most infraspecific taxa were described under Hieracium s.l. and to avoid too much invalid names under Pilosella in the list, a separation of Hieracium and Pilosella is remained undone. By coloured marking additional informations are given whether a subspecies is originally described from a german federal state or its name has a syntype from Germany. KW - diversity KW - Hieracium KW - Asteraceae KW - Habichtskraut KW - Korbblütler KW - Langhaariges Habichtskraut Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-198175 UR - http://forum-geobotanicum.net/articles/vol_9-2020/gottschlich-synopsis_hieracium/gottschlich-synopsis_hieracium.pdf SN - 1867-9315 VL - 9 ER - TY - JOUR A1 - Dosso, Kanvaly A1 - Yeo, Kolo A1 - Konate, Souleymane A1 - Linsenmair, Karl Eduard T1 - Importance of protected areas for biodiversity conservation in central Cote d'Ivoire: Comparison of termite assemblages between two neighboring areas under differing levels of disturbance JF - Journal of Insect Science N2 - To highlight human impact on biodiversity in the Lamto region, termites were studied with regard to their use as bio-indicators of habitat change in the tropics. Using a standardized method, termites were sampled in the three most common habitat types, i.e., in semi-deciduous forest, savanna woodland, and annually burned savanna, all inside Lamto Reserve and its surrounding rural domain. Termite species richness fell from 25 species in the Lamto forest to 13 species in the rural area, involving strong modification in the species composition (species turnover = 59 %). In contrast, no significant change in diversity was found between the Lamto savannas and the rural ones. In addition, the relative abundance of termites showed a significantly greater decline in the rural domain, even in the species Ancistrotermes cavithorax (Sjostedt) (Isoptera: Termitidae), which is known to be ecologically especially versatile. Overall, the findings of this study suggest further investigation around Lamto Reserve on the impact of human activities on biodiversity, focusing on forest conversion to land uses (e.g. agricultural and silvicultural systems). KW - species richness KW - Savanna KW - trinervitermes KW - rural domain KW - ant communities KW - gradient KW - Amazonia KW - forest disturbance KW - diversity KW - soil macrofauna KW - West Africa KW - land use KW - burned savanna KW - forest KW - Lamto Reserve KW - relative abundance KW - savanna woodland KW - species composition Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133218 VL - 12 IS - 131 ER - TY - JOUR A1 - Kessler, Michael A1 - Hertel, Dietrich A1 - Jungkunst, Hermann F. A1 - Kluge, Jürgen A1 - Abrahamczyk, Stefan A1 - Bos, Merijn A1 - Buchori, Damayanti A1 - Gerold, Gerhard A1 - Gradstein, S. Robbert A1 - Köhler, Stefan A1 - Leuschner, Christoph A1 - Moser, Gerald A1 - Pitopang, Ramadhanil A1 - Saleh, Shahabuddin A1 - Schulze, Christian H. A1 - Sporn, Simone G. A1 - Steffan-Dewenter, Ingolf A1 - Tjitrosoedirdjo, Sri S. A1 - Tscharntke, Teja T1 - Can Joint Carbon and Biodiversity Management in Tropical Agroforestry Landscapes Be Optimized? JF - PLoS One N2 - Managing ecosystems for carbon storage may also benefit biodiversity conservation, but such a potential 'win-win' scenario has not yet been assessed for tropical agroforestry landscapes. We measured above-and below-ground carbon stocks as well as the species richness of four groups of plants and eight of animals on 14 representative plots in Sulawesi, Indonesia, ranging from natural rainforest to cacao agroforests that have replaced former natural forest. The conversion of natural forests with carbon stocks of 227-362 Mg C ha\(^{-1}\) to agroforests with 82-211 Mg C ha\(^{-1}\) showed no relationships to overall biodiversity but led to a significant loss of forest-related species richness. We conclude that the conservation of the forest-related biodiversity, and to a lesser degree of carbon stocks, mainly depends on the preservation of natural forest habitats. In the three most carbon-rich agroforestry systems, carbon stocks were about 60% of those of natural forest, suggesting that 1.6 ha of optimally managed agroforest can contribute to the conservation of carbon stocks as much as 1 ha of natural forest. However, agroforestry systems had comparatively low biodiversity, and we found no evidence for a tight link between carbon storage and biodiversity. Yet, potential win-win agroforestry management solutions include combining high shade-tree quality which favours biodiversity with cacao-yield adapted shade levels. KW - forest soils KW - stocks KW - diversity KW - sequestration KW - conversion KW - balance KW - root Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-132016 VL - 7 IS - 10 ER - TY - JOUR A1 - Gámez-Virués, Sagrario A1 - Perović, David J. A1 - Gossner, Martin M. A1 - Börschig, Carmen A1 - Blüthgen, Nico A1 - de Jong, Heike A1 - Simons, Nadja K. A1 - Klein, Alexandra-Maria A1 - Krauss, Jochen A1 - Maier, Gwen A1 - Scherber, Christoph A1 - Steckel, Juliane A1 - Rothenwöhrer, Christoph A1 - Steffan-Dewenter, Ingolf A1 - Weiner, Christiane N. A1 - Weisser, Wolfgang A1 - Werner, Michael A1 - Tscharntke, Teja A1 - Westphal, Catrin T1 - Landscape simplification filters species traits and drives biotic homogenization JF - Nature Communications N2 - Biodiversity loss can affect the viability of ecosystems by decreasing the ability of communities to respond to environmental change and disturbances. Agricultural intensification is a major driver of biodiversity loss and has multiple components operating at different spatial scales: from in-field management intensity to landscape-scale simplification. Here we show that landscape-level effects dominate functional community composition and can even buffer the effects of in-field management intensification on functional homogenization, and that animal communities in real-world managed landscapes show a unified response (across orders and guilds) to both landscape-scale simplification and in-field intensification. Adults and larvae with specialized feeding habits, species with shorter activity periods and relatively small body sizes are selected against in simplified landscapes with intense in-field management. Our results demonstrate that the diversity of land cover types at the landscape scale is critical for maintaining communities, which are functionally diverse, even in landscapes where in-field management intensity is high. KW - land-use intensity KW - community functional-responses KW - body-size KW - agricultural intensification KW - sustainable intensification KW - managed grasslands KW - biodiversity KW - diversity KW - heterogenity KW - butterflies Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-141925 VL - 6 IS - 8568 ER - TY - THES A1 - Claßen, Alice T1 - Diversity, traits and ecosystem services of pollinators along climate and land use gradients on Mount Kilimanjaro T1 - Diversität, Merkmale und Ökosystemfunktionen von Bestäubern entlang von Klima- und Landnutzungsgradienten am Kilimandscharo N2 - Since more than two centuries naturalists are fascinated by the profound changes in biodiversity observed along climatic gradients. Although the theories explaining changes in the diversity and the shape of organisms along climatic gradients belong to the foundations of modern ecology, our picture on the spatial patterns and drivers of biodiversity is far from being complete. Ambiguities in theory and data are common and past work has been strongly concentrated on plants and vertebrates. In the last two decades, interest in the fundamental processes structuring diversity along climatic gradients gained new impetus as they are expected to improve our understanding about how ecosystems will respond to global environmental changes. Global temperatures are rising faster than ever before; natural habitats are transformed into agricultural land and existing land use systems get more and more intensified to meet the demands of growing human populations. The fundamental shifts in the abiotic and biotic environment are proclaimed to affect ecosystems all over the world; however, precise predictions about how ecosystems respond to global changes are still lacking. We investigated diversity, traits and ecosystem services of wild bees along climate and land use gradients on Mount Kilimanjaro (Tanzania, East Africa). Wild bees play a major role in ecosystems, as they contribute to the reproduction and performance of wild and crop plants. Their responsiveness to environmental changes is therefore of high ecological and economic importance. Temperature and energy resources have often been suggested to be the main determinants of global and local species richness, but the mechanisms behind remain poorly understood. In the study described in chapter II we analyzed species richness patterns of wild bees along climate and land use gradients on Mount Kilimanjaro and disentangled the factors explaining most of the changes in bee richness. We found that floral resources had a weak but significant effect on pollinator abundance, which in turn was positively related to species richness. However, temperature was the strongest predictor of species richness, affecting species richness both directly and indirectly by positively influencing bee abundances. We observed higher levels of bee-flower-interactions at higher temperatures, independently of flower and bee abundances. This suggests that temperature restricts species richness by constraining the exploitation of resources by ectotherms. Current land use did not negatively affect species richness. We conclude that the richness of bees is explained by both temperature and resource availability, whereas temperature plays the dominant role as it limits the access of ectotherms to floral resources and may accelerate ecological and evolutionary processes that drive the maintenance and origination of diversity. Not only species numbers, but also morphological traits like body size are expected to be shaped by both physiological and energetic constraints along elevational gradients. Paradoxically, Bergmann´s rule predicts increases of body sizes in cooler climates resulting from physiological constraints, while species-energy theory suggests declines in the mean body size of species caused by increased extinction probabilities for large-bodied species in low-energy habitats. In chapter III we confronted this ambiguity with field data by studying community-wide body size variation of wild bees on Mt. Kilimanjaro. We found that along a 3680 m elevational gradient bee individuals became on average larger within species, while large species were increasingly absent from high-elevational communities. This demonstrates, on the one hand, how well-established, but apparently contrasting ecological theories can be merged through the parallel consideration of different levels of biological organization. On the other hand it signals that the extinction risk in the course of environmental change is not equally distributed among species within a community. Land use intensification is known to threaten biodiversity, but the consequences for ecosystem services are still a matter of debate. In chapter IV, we experimentally tested the single and combined contributions of pest predators and pollinators to coffee production along a land use intensification gradient on Mount Kilimanjaro. We found that pest predation increased fruit set by on average 9%, while pollination increased fruit weight of coffee by on average 7.4%. Land use had no significant effect on both ecosystem services. However, we found that in coffee plantations with most intensified land use, pollination services were virtually exclusively provided by the honey bee (Apis mellifera). The reliance on a single pollinator species is risky, as possible declines of that species may directly lower pollination services, resulting in yield losses. In contrast, pollination services in structurally complex homegardens were found to be provided by a diverse pollinator community, increasing the stability of pollination services in a long term. We showed that on Mount Kilimanjaro pollinator communities changed along elevational gradients in terms of species richness (chapter II) and trait composition (chapter III). Temperature and the temperature-mediated accessibility of resources were identified as important predictors of these patterns, which contributes to our fundamental understanding about the factors that shape ectothermic insect communities along climatic gradients. The strong temperature-dependence of pollinators suggests that temperature shifts in the course of global change are likely to affect pollinator communities. Pollinators might either profit from rising temperatures, or shift to higher elevations, which could result in related biotic attrition in the lowland with consequences for the provision of ecosystem services in cropping systems. Up to now, land use intensification had no significant impact on the diversity of pollinator communities and their ecosystem services. Pollinators might profit from the strong landscape heterogeneity in the region and from the amount of flower resources in the understory of cropping systems. However,progressing homogenization of the landscape and the pronounced application of pesticides could result in reduced diversity and dominance of single species, as we already found in sun coffee plantations. Such shifts in community compositions could threaten the stability of ecosystem services within cropping and natural systems in a long term. N2 - Die Biodiversität auf der Erde ist nicht gleichmäßig verteilt, sondern verändert sich entlang klimatischer Gradienten – ein Phänomen, das Naturwissenschaftler schon seit mehr als zwei Jahrhunderten fasziniert. Über die Mechanismen, welche die Verteilung von Arten entlang von Klimazonen bestimmen, besteht nach wie vor keine Einigkeit, auch wenn viele der hier hervorgebrachten Theorien zu den Grundlagen der modernen Ökologie gehören. Ambivalenzen in den Erklärungsmodellen und erhobenen Daten sind häufig und bisherige Studien konzentrierten sich vorrangig auf Pflanzen und Vertebraten, während andere Taxa weniger Beachtung fanden. Die Unsicherheit über die Auswirkungen des globalen Wandels auf Ökosysteme und die Konsequenzen für Ökosystemdienstleistungen setzte neue Impulse im Bereich der Biodiversitätsforschung. Temperaturen steigen so schnell wie nie zuvor; natürliche Habitate werden zunehmend in Agrarflächen umgewandelt und bestehende Landwirtschaftssysteme werden intensiviert. Präzise Vorhersagen darüber, wie Ökosysteme auf solch drastische Umweltveränderungen reagieren, fehlen jedoch weitgehend. In dieser Dissertation wird gezeigt, wie sich die Artenvielfalt, morphologische Merkmale und Ökosystemfunktionen von Bienen entlang von Klima- und Landnutzungsgradienten des Kilimandscharos (Tansania, Ostafrika) verändern. Bienen spielen eine wichtige Rolle in Ökosystemen, da sie als Bestäuber zur Reproduktion und Produktivität von Wild- und Nutzpflanzen beitragen. Die Veränderung ihres Artenreichtums, ihrer Merkmale und ihrer Ökosystemdienstleistungen entlang von Umweltgradienten ist somit von großer ökologischer und ökonomischer Relevanz. Temperatur und die Verfügbarkeit von Ressourcen sind die Faktoren, mit denen globale und lokale Muster von Diversität am häufigsten erklärt werden. Die kausalen Zusammenhänge über welche die Temperatur und die Verfügbarkeit von Ressourcen eine Erhöhung der Artenvielfalt bewirken, sind jedoch nach wie vor unklar. Im zweiten Kapitel dieser Arbeit wurde untersucht, wie sich der Artenreichtum von Bienen entlang von Klima- und Landnutzungsgradienten des Kilimandscharos verändert und welche Faktoren für diese Veränderungen verantwortlich sind. Blühressourcen hatten einen schwachen, aber signifikanten Einfluss auf die Bestäuberabundanzen, welche wiederum einen Großteil des Artenreichtums erklärten. Insgesamt hatte die Temperatur jedoch einen deutlich stärken Einfluss auf die Artenvielfalt als die Verfügbarkeit von Blühressourcen: Die Temperatur wirkte sich direkt, möglicherweise über einen Erhöhung von Speziationsraten, und indirekt, über eine Erhöhung der Bienenabundanz, auf die Artenvielfalt von Bienen aus. Zusätzlich konnte beobachtet werden, dass die Blütenbesuche von Bienen unabhängig von der Blütendichte und der Bienenabundanz, mit einem Anstieg der Temperatur zunahmen. Aus diesen Beobachtungen folgern wir, dass bei Ektothermen die Nutzbarkeit von Ressourcen durch die Temperatur gesteuert sein könnte. Die Untersuchung morphologischer Merkmale entlang von Umweltgradienten erlaubt es, deterministische von stochastischen Prozessen bei der Zusammensetzung von Artengemeinschaften zu unterscheiden. Während bei stochastischen Prozessen Merkmale entlang von Umweltgradienten zufällig aus Artengemeinschaften ausscheiden sollten, wird im Falle deterministischer Prozesse ein gerichtetes Muster erwartet. Unter den deterministischen Prozessen konkurrieren bezüglich der Körpergröße zwei scheinbar konträre Theorien: Während die Bergmannsche Regel vorhersagt, dass große Tiere, aufgrund eines verbesserten Oberflächen-Volumen-Verhältnisses, einen Vorteil in kühlen Regionen haben, weist die Arten-Energie-Theorie größeren Arten eine erhöhte Aussterbewahrscheinlichkeit in energielimitierten, kühlen Gebieten zu, so dass die mittlere Körpergröße von Lebensgemeinschaften bei kälterer Temperatur sinken sollte. Im dritten Kapitel dieser Dissertation untersuchten wir, ob sich morphologische Merkmale von Wildbienen mit zunehmender Höhe verändern. Dabei betrachteten wir nicht nur Merkmalsveränderungen innerhalb von Artengemeinschaften, sondern auch innerartliche Veränderungen. Sowohl physiologische als auch energetische Restriktionen prägten die Merkmalskompositionen, allerdings auf unterschiedlichen biologischen Ebenen. So nahm die Körpergröße innerhalb von Arten mit der Höhe im Durchschnitt zu (=Bergmannsche Regel), während auf Gemeinschaftsebene kleinere Arten die Hochgebirgsregionen dominierten (=energetische Restriktion). Die parallele Betrachtung der intra- und interspezifischen Ebene ermöglichte es uns, scheinbar konträre ökologische Theorien zusammenzuführen. Zudem konnten wir zeigen, dass Merkmale nicht zufällig, sondern gerichtet aus Artengemeinschaften gefiltert werden. Landnutzungsintensivierung bedroht Biodiversität, aber die Konsequenzen für Ökosystemdienstleistungen sind nach wie vor ungewiss. Im vierten Kapitel dieser Arbeit prüften wir mit Hilfe von einzelnen und kombinierten Bestäuber- und Prädatorausschlussexperimenten, welchen Beitrag Bestäuber, Vögel und Fledermäuse in verschiedenen Anbausystemen zur Kaffeeproduktion am Kilimandscharo leisten. Wir zeigten, dass sich Bestäuber und Prädatoren in ihren Effekten ergänzten: Während Bestäuber eine Steigerung des Kaffeebohnengewichtes um durchschnittlich 7.4% bewirkten, konnte durch die Prädation von Schädlingen der Fruchtansatz des Kaffees um durchschnittlich 9% gesteigert werden. Landwirtschaftliche Intensivierung, von komplexen Waldwirtschaftssystemen, über beschattete Kaffeeplantagen, bis hin zu Sonnenplantagen hatte keinen negativen Effekt auf die Ökosystemdienstleistungen von Bestäubern und Prädatoren. Wir konnten jedoch nachweisen, dass in Waldwirtschaftssystemen eine diverse Bestäubergemeinschaft den Kaffee bestäubt, während in Sonnenplantagen fast ausschließlich die Honigbiene als Bestäuber fungiert. Eine solche Verschiebung der Bestäuber-komposition könnte die langfristige Stabilität intensiv genutzter Flächen gefährden. In dieser Dissertation zeigten wir, wie sich Bestäubergemeinschaften am Kilimandscharo entlang von Höhengradienten bezüglich ihrer Artenvielfalt (Kapitel II) und ihrer Merkmale (Kapitel III) verändern. Temperatur und temperatur-gesteuerte Ressourcennutzbarkeit wurden als maßgebende Determinanten dieser Muster identifiziert. Damit wurde ein Beitrag zur Identifikation von Gesetzmäßigkeiten in der Verteilung ektothermer Insekten entlang von Klimagradienten geleistet. Unsere Ergebnisse weisen darauf hin, dass Klimaveränderungen im Zuge des globalen Wandels Konsequenzen für Bestäubergemeinschaften haben könnten. Eventuell könnten Bestäuber von den steigenden Temperaturen profitieren. Gleichsam könnte es aber auch zu einer Verschiebung von Bestäubern in höher gelegene Regionen und zu einem daran gekoppelten Einbruch der Bestäubungsleistungen in tiefliegenden Kulturlandschaften kommen. Im Hinblick auf die Konsequenzen anthropogener Landnutzung wurde festgestellt, dass die landwirtschaftliche Intensivierung am Kilimandscharo bisher keinen messbaren negativen Effekt auf die Ökosystemdienstleitungen von Bestäubern hatte. Die Bestäuber profitieren vermutlich von der starken Landschaftsheterogenität der Region und zahlreichen krautigen Blühressourcen im Unterwuchs von Agrarflächen. Eine zunehmende Homogenisierung der Landschaft und ein verstärkter Einsatz von Pestiziden könnten jedoch, wie auf Sonnenplantagen bereits zu finden, zu einer Dominanz von einigen wenigen Arten führen, welches zusammen mit der klimabedingten Artenverschiebung die langfristige Stabilität von Agrarsystemen und natürlichen Systemen gefährden könnte. KW - Kilimandscharo KW - Bestäuber KW - Biodiversität KW - Höhengradient KW - Landnutzungsgradient KW - Arten-Energy-Theory KW - species-energy-theory KW - elevational gradient KW - Kilimanjaro KW - pollinators KW - diversity KW - ecosystem service KW - ecology Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-101292 ER -