Browsing by Subject "Habitat"

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Habitat use and morphological adaptations of endemic rodents (Muroidea: Nesomyinae) of East Madagascar
(2014) Marquart, Kathrin; Steidle, Johannes
In an adaptive radiation, Madagascar’s endemic rodents colonised a variety of different habitats. In this thesis, ecological and morphological aspects of the frequently sympatric nesomyines of East Madagascar were analysed. In the first part of the study, vegetation analyses were conducted in a model rainforest in East Madagascar and compared with species distribution to describe the species ecology. The results represent a preliminary ecological classification of the habitat use of nesomyines. In the second part of the study, the morphology of the hands and feet (chiridia) was correlated with ecological parameters and habitat use for the first time. Adaptive differentiations of the chiridia give evidence of a species’ ecological niche. Certain patterns of the volar integument, epidermal structures as well as length and area ratios are discussed in respect of their functional and ecological adaptive value. Seven endemic rodent species (Eliurus grandidieri, E. minor, E. tanala, E. webbi, Nesomys rufus, Gymnuromys roberti, Brachytarsomys albicauda) were trapped with live traps in different microhabitats. Ecological data and information on habitat structures were collected along five 1 km long trails. The specialised rodents were found in different ecological niches: on trees, lianas, underneath wood and thick roots, in dead wood or rotten logs. Some were found close to small rivers, some in humid valleys, whereas others seemed to prefer the higher mountain slopes or misty ridges, up to 1200 m a.s.l. Microhabitat analyses were conducted and trails where a species was significantly more abundant were compared with those where it was rare. The presence of an endemic rodent species was strongly connected with forest type, forest structure and vegetation density. In contrast, the deforested and cleared areas were species-poor. For the morphological studies, detailed microscopic drawings of the hands and feet were prepared of voucher specimens to be compared between the species. The chiridian structures differed clearly between the seven species. Slender hind feet with small thenar pads were significantly correlated with a terrestrial locomotion and a ground-dwelling ecology. Species with a predominantly arboreal locomotion exhibit large and prominent pads, covering a great area of the chiridian surface. Large-tree-climbers have larger pads in relation to foot size than bamboo-grass and small-branch-climbers which possess relatively longer feet with longer toes. Climbing on large trees needs good adhesive properties and climbing on grass or thin branches needs good grasping abilities. In conclusion, certain morphological structures of the rodents chiridia are evidence of a special way of life and foot-pad morphology in particular mirrors special adaptations to a species habitat. These adaptations are regarded as important to understand niche occupation, certain ecological aspects and locomotion forms of sympatric species. Thus, habitat preferences and special habitat requirements of the endemic nesomyines of East Madagascar could be analysed in details. In this thesis, it could be documented for the first time by the combination of these ecological and morphological results that the chiridian morphology allows to differentiate nesomyine taxa on ecological level.
Microbiota and nutrient portraits of European roe deer (Capreolus capreolus) rumen contents in characteristic Southern German habitats
(2023) Dahl, Sarah-Alica; Seifert, Jana; Camarinha-Silva, Amélia; Cheng, Yu-Chieh; Hernández-Arriaga, Angélica; Hudler, Martina; Windisch, Wilhelm; König, Andreas
Roe deer ( Capreolus capreolus ) are found in various habitats, from pure forest cultures to agricultural areas and mountains. In adapting to the geographically and seasonally differentiating food supply, they depend, above all, on an adapted microbiome. However, knowledge about the microbiome of wild ruminants still needs to be improved. There are only a few publications for individual species with a low number of samples. This study aims to identify a core microbiota for Bavarian roe deer and present nutrient and microbiota portraits of the individual habitat types. This study investigated the roe deer’s rumen (reticulorumen) content from seven different characteristic Bavarian habitat types. The focus was on the composition of nutrients, fermentation products, and the rumen bacterial community. A total of 311 roe deer samples were analysed, with the most even possible distribution per habitat, season, age class, and gender. Significant differences in nutrient concentrations and microbial composition were identified for the factors habitat, season, and age class. The highest crude protein content (plant protein and microbial) in the rumen was determined in the purely agricultural habitat (AG), the highest value of non-fibre carbohydrates in the alpine mountain forest, and the highest fibre content (neutral detergent fibre, NDF) in the pine forest habitat. Maximum values for fibre content go up to 70% NDF. The proportion of metabolites (ammonia, lactate, total volatile fatty acids) was highest in the Agriculture-Beech-Forest habitat (ABF). Correlations can be identified between adaptations in the microbiota and specific nutrient concentrations, as well as in strong fluctuations in ingested forage. In addition, a core bacterial community comprising five genera could be identified across all habitats, up to 44% of total relative abundance. As with all wild ruminants, many microbial genera remain largely unclassified at various taxonomic levels. This study provides a more in-depth insight into the diversity and complexity of the roe deer rumen microbiota. It highlights the key microorganisms responsible for converting naturally available nutrients of different botanical origins.