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Having been regarded as wastelands until quite recently, wetlands are increasingly acknowledged as ecosystems of high biodiversity. Wetland restoration projects are often accompanied by the implementation of specific species management programs. Naturally, for effective management measures, profound knowledge of the target speciesʼ ecological requirements is obligatory, including habitat selection, feeding ecology as well as spatial behaviour such as movements within and between patches of suitable habitat. Yet, big knowledge gaps exist for many marshland birds which is particularly true for highly secretive species such as rails and crakes. Considered as the least known among the Palaearctic breeding birds, most information about the Baillon's Crake Zapornia pusilla is only anecdotic, resulting in strong uncertainties with regard to the species' distribution, population sizes, status, migratory behaviour as well as ecological requirements. This can be mainly attributed to the species' skulking behaviour and its seemingly highly erratic occurrence. Baillon's Crakes in the Western Palaearctic and Palaeotropics are referred to as the subspecies Z. p. intermedia. While European breeding birds are assumed to winter in sub-Saharan wetlands, African populations are considered rather to be itinerant with local movements induced by seasonal or anthropogenic habitat changes. However, for both migratory movements, major directions or routes are unknown. The discovery of a large number of Baillon's Crakes presumably wintering in the floodplains of the Parc National des Oiseaux du Djoudj (PNOD), situated in the Senegal River Delta, WAfrica, initiated this thesis. The main aim of the study was, firstly, to clarify the status and size of this population and assess its connectivity to European breeding population(s). Secondly, in order to improve the knowledge about the species' ecological requirements as a basis for the National Parks conservation management, habitat selection, spatial behaviour as well as dietary selectivity were investigated. The major part of the fieldwork was performed in PNOD in the course of the dry season during periods of 1.5 - 2.5 months from December - March 2009, 2010 and 2013. Baillon's Crakes were mainly caught with cage traps, ringed and common measurements were taken, including moult status. Skin tissue as well as one rectrice was sampled for DNA and stable isotope analyses. This was also done for Baillon's Crakes caught in European breeding grounds in Germany, Montenegro and Southern Spain. For dietary analyses, faecal samples were collected in PNOD in winter 2009/2010. Furthermore, some individuals were equipped with radio-transmitters to determine home range size and habitat selection. For the identification of the most relevant habitat parameters both on a population as well as on the individuals' level, we used a vegetation map based on satellite imagery covering the entire Djoudj area as well as maps generated on the basis of aerial photographs taken at two study sites.
Many ethicists consider the rule of nonmaleficence – Do no harm! – to be the most fundamental ethical rule and key to ethics. This rule is taken as the foundation of the present work. I argue that any entity, that can be harmed, ought to be morally considered. Only those entities can be harmed that are inherently goal-directed or striving – in other words, that possess a telos. The reason is that by constantly acting in ways to preserve their being and to prevent their own not-being, goal-directed entities express that they value their own good. To harm such a goal-directed entity therefore means to act against the values and the good of it. The argument so far supports ethical biocentrism, that is, the view that all living, goal-directed beings are harmable, possess interests, and are, thus, morally considerable, while non-living beings are not. Yet, I digress from classical biocentrism since I conclude, based on analysis of evolutionary and biological findings, that the locus of goal-directedness and potential harm is also, if not foremost, situated in genes. Within many species, individual organisms sacrifice themselves for the betterment of their descendants like in praying mantises where males sacrifice themselves and are eaten by the female during copulation. This shows that it is not necessarily the organism as an individual which follows its own interests and goals. Individual organisms are – to a high degree – “directed” by their genes. Even in highly developed animals, genes play a significant role in the goal-directedness of the individuals. An adult human organism, for example, consists of trillions of individual cells. However, all these cells are derived from a single cell – the fertilized egg. Each of our lives begins with a single cell that contains almost all information to finally form our functioning body. Where do all the instructions, the goal-directedness come from to finally form an adult organism if not from the genes contained in this first cell, the zygote? It is the genes of each zygote that contain a set of information for making the appropriate adult. Organisms are largely programmed to do everything necessary to stay in existence, to survive, and finally to pass on their genes successfully – either by reproducing or by helping close relatives that carry a similar set of genes. The main interests of genes lie in their continued existence. This necessitates reproduction since the gene-carrying organisms will inevitably die. Single genes, though, are difficult to morally consider directly since they perform entirely in and through individual organisms. Without the individual organisms, genes cannot survive. The good news for ethics is that the interests of genes and organism usually converge: individual organisms try to survive – as do their genes. In practice, it thus makes much more sense to give moral attention to entire organisms instead of single genes. An advantage of the gene-centric ethical theory proposed here is that the moral relevance of future generations and species can be “directly” justified: Since genes have an interest in their continued existence (in the form of identical copies), they would be harmed if future generations were doomed to inexistence. Within a species with many individuals, each gene is likely to be represented in many organisms. The smaller the gene pool of a species gets, the less likely is the existence of the same gene and, therefore, the less likely is the fulfillment of its fundamental interests. Hence, saving one of the last individuals of an endangered species would be ethically preferable to saving an individual of a populous species. Unfortunately, moral conflicts are abundant – not only concerning biodiversity conservation. We often have to choose between harming either entity A or entity B – for example in the daily questions of food and eating. In such cases, a strictly egalitarian theory (especially an egalitarian biocentric one) would be no real help and without any guiding power. Therefore, on a second level of morality, we have to include additional criteria that help to minimize the overall harm. For these criteria to be objective, universalizable, and thus moral ones, I apply a number of widely accepted ethical principles like the principle of proportionality, impartiality, self-defense, and universalizability. By recurring to these principles, I identify a set of morally relevant criteria for a fair resolution of moral conflict situations which help to minimize the overall harm done. The identified criteria are: (phylogenetic) nearness, endangerment, r- or K-selected species, evolutionary distinctiveness, ability to regrow and to regenerate, pain-susceptibility, and ecosystematic role. In sum, my gene-centric environmental ethical theory provides numerous reasons and arguments for biodiversity conservation – for protecting genes, organisms, species, and ecosystems alike – without neglecting the needs of humans.
Main drivers for biodiversity loss in terrestrial ecosystems are changes in land use, climate change, enhanced nitrogen deposition and biotic exchange (invasive species). These drivers also affect dry, nutrient-poor open anthropo-zoogenic inland and coastal heathlands which often harbor a high biodiversity. To counteract biodiversity loss in coastal ecosystems, a basic step is the assessment of the various threats. Therefore it is important to select suitable model organisms for analyses of biodiversity dynamics. In this thesis the three arthropod groups Orthoptera (Ensifera and Caelifera), carabid beetles (Coleoptera: Carabidae) and spiders (Araneae) were studied, as they are very useful indicators. Besides sampling of the three arthropod groups vegetation and microclimate parameters were recorded. The studies were done between 2008 and 2010 in the coastal heathland on the Baltic island of Hiddensee, Germany. The main aim of the thesis was to analyze the impact of three drivers of heathland biodiversity loss (succession, grass encroachment, moss invasion) on the selected indicator arthropod groups. Based on this multi-level and -species approach, implications for the conservation of coastal heathlands are given. The results show that successional processes and grass encroachment have strong impact on species richness and abundance, species composition and functional groups, as well as life-history traits and functional diversity of the arthropod groups. Main findings were: Orthoptera species richness was highest in the intermediate stages (heath encroached by grasses and heath with shrubs) because of higher habitat heterogeneity and higher food supply (grasses). Opposed to that, species richness of ground-dwelling carabid beetles and spiders did not differ among the five successional stages, which contradicts the ‘habitat heterogeneity hypothesis’. In contrast to species richness, functional diversity differed among successional stages. The concept of functional diversity – which integrates species life-history trait data – therefore might be particularly suitable for biodiversity research, while the explanatory power of species richness alone might not be sufficient. The species compositions of all three taxa changed remarkably along the coastal heathland gradient indicating a high species turnover. In particular, open, dynamic habitats (‘grey dunes’ and ‘dwarf-shrub heath’) could be separated. Here, several specialized, xerothermic and threatened species occurred due to the extreme habitat conditions, but are displaced during grass and shrub encroachment. On a smaller spatial scale, the invasion of Campylopus introflexus alters habitat conditions in grey dunes and therefore affects carabid beetle and spider species and the dominant Orthoptera species Myrmeleotettix maculatus. Species richness of carabid beetles and spiders, and the abundance of adult M. maculatus grasshoppers were reduced. Species compositions of carabids and spiders changed remarkably with a loss of several species. These negative impacts could be explained by the vegetation structure of the moss which is unsuitable for web-building spiders or large carabid beetles, and by reduced germination of higher plants and therefore reduced food supply for M. maculatus and phytophagous carabid species. Within the open coastal heathland, the mosaic of grey dunes and adjacent dwarf-shrubs is important since many species perform a habitat change during their development and, besides the scarcely vegetated, thermally benefited grey dunes, need denser vegetation of adjacent dwarf-shrubs for shelter, as song posts, or for foraging. As grey dunes harbor a high abundance and species richness of threatened and specialized, mainly xerothermic and geobiont species and are important as oviposition and nymphal habitat, they are regarded as a keystone habitat within the coastal heathland. Besides these ecological studies, two studies focused on the method of pitfall trapping. It could have been shown, that pitfall trapping might be a useful sampling method for Orthoptera in open habitats. The other study demonstrated that sampling interval has a strong influence on the capture efficiency of several arthropod groups (‘digging-in effect’). Conservation practices should aim at maintaining a heterogeneous heathland mosaic with open grey dunes and Calluna stands, in addition to scattered grassy and shrub-encroached heath for the survival of species-rich heathland arthropod assemblages with a high proportion of specialized and threatened species.