All animal and plant species have a specific area of distribution. The distribution of a species in space and time is neither accidental nor uniform, but the result of recent ecological factors (e.g. biocoenoses, climate, soils, humans) and historical events (e.g. plate tectonics, climate and usage history). Chorology, as one of the classical fields of work within biogeography, deals with the structure and dynamics of distribution areas as well as with the processes that lead to certain distribution patterns.
Chorologic studies are therefore an essential prerequisite for understanding the biogeographic origin and evolutionary history of species. Furthermore, this knowledge is a prerequisite for the development of sound conservation concepts, which is why classical biogeography is becoming increasingly important in European institutions. At the Department of Biogeography at the University of Trier, we collect basic chorologic data for different groups of organisms at different spatial levels and in different regions, in order to use these data for scientific or nature conservation issues.
Biomonitoring is in general the monitoring of environmental quality with the help of organisms (bioindicators). This involves decoding the by bio-indicators provided information on the state of the environment to obtain an indication of anthropogenic environmental pollution. By measuring (harmful) substance concentrations in organisms and determining their effects on organisms, valuable conclusions can be drawn about the hazardousness of substances, including for humans. Metabarcoding methods can also be used to reconstruct entire communities of species from environmental samples. For example, communities of tree-dwelling insects or leaf-associated microbial communities can be characterized from leaf samples. This in turn allows conclusions to be drawn about the effect of environmental stress on the composition and stability of ecosystems.
Staff members of the Department of Biogeography support the standardization of biomonitoring methods with wildlife as well as higher and lower plants through their work in the Federal Environmental Specimen Bank (link to internal page) and their participation in the Commission on Air Pollution Control in the VDI and DIN (KRdL), in the GDCh Working Group on Environmental Monitoring and in other committees.
The global decline of biodiversity is a major problem of modern humankind. The major threats to biodiversity are habitat loss, degradation and fragmentation, introduction of non-native animal species, plant species and pathogens, overharvesting, pollution and climate change. The international community agreed upon halting biodiversity loss by 2020 in the Aichi Targets of the Convention on Biodiversity as well as in the European Biodiversity Strategy. In order to reach this target, information on the current conservation status of biodiversity, on the consequences of human activities as well as on the effects of conservation efforts is needed.
The field of conservation biology is therefore a central subject of the Biogeography group in Trier. We study regionally and internationally the status of several groups of organisms (including amphibians, reptiles, mammals, birds, fishes, grasshoppers, wild bees and beetles). Our aim is to obtain insight into their ecological requirements, their population structure, their geographic distribution as well as their threats. These analyses help us to develop conservation plans for threatened species or habitats.
Each species of flora and fauna has its own typical habitat and fills its specific ecological niche. You could say that the site is the "address" and the niche is the "profession".
Conversely, if information about the ecological niche is known, the possible occurrence can be predicted. This is precisely the principle behind the concept of ecological niche modelling: one takes the known habitats of a species and characterises their ecological information. This is often data from climate maps or satellite images. The resulting "matrix" as a whole reflects part of the ecological niche of the species in question.
Using mathematical methods, sites where the species has not been identified are then examined for their similarity to the "matrix". The degree of similarity indicates how likely a species is - or can be - found at these locations. Whether this is really the case depends on numerous other factors. One therefore speaks of potential distribution.
Information on the known occurrence of species can thus be used to model potential distributions over an area. We apply ecological niche modelling, also known as "species distribution models", to various biogeographical questions and in nature conservation. The modelled areas can also be projected into the past and future using climate models. In this way, area shifts over time (since the Ice Age, for example) can be determined or predictions made as to how species react to global climate change.
In the face of the global biodiversity crisis, there is a growing need for a better understanding of the interactions of organisms with their living and non-living environment. Our basic ecological research contributes to this. The focus is on the analysis of realized and potential ecological niches, a better understanding of the demographic structure of populations (e.g. age structure) and its changes, as well as interactions between populations (e.g. dispersion and migration behavior, intraspecific and interspecific competition, food webs). We investigate this on selected groups of organisms, with a focus on beetles, grasshoppers, spiders, amphibians, reptiles, birds and mammals.
The processes responsible for the current distribution of species, which took place in the past, have left their traces in the genomes of organisms. Today we have a wide range of molecular genetic methods at our disposal to decipher them and thus reconstruct the spatial and temporal history of the distribution areas. Geographical focuses of our phyogeographical research are the Mediterranean region, the Canary Islands, South America and Hawaii, with special emphasis on amphibians, locusts and spiders. The sequencing of mitochondrial and nuclear DNA are the methods we use most frequently. Modern approaches to data analysis allow us to derive historical processes of areal genesis as well as demographic trends of populations over time.
Populations as one of the central biological units are reproductive communities of individuals of a species that populate a spatially usually clearly defined area. A multitude of microevolutionary processes take place within them. Mutations alter characteristics which are then retained or lost again according to their adaptation value (selection). However, even random processes (genetic drift) can lead to the loss or reassertion of characteristics. Finally, the exchange of individuals between populations leads to the introduction of new traits into populations. Population genetics attempts to reconstruct all these processes. To do so, it analyses the distribution of genetic traits within and between populations of a species (usually using molecular methods). The results allow conclusions to be drawn about gene exchange between populations. In a cultural landscape characterised by fragmentation such as that of Central Europe, population genetics thus makes an important contribution to the conservation of endangered species.
Phylogenetic family trees today form the basis for understanding the diversity of organisms and their development. They represent phylogenetic hypotheses for the reconstruction of which we use molecular genetic methods, in particular the sequencing of nuclear and organelle DNA. However, the resulting family trees do not only describe the kinship relations of the organisms. They also help us to understand the spatial and temporal processes of species formation (phylogeography) and to answer questions about the evolution of their morphology, behaviour and ecological interference.