PhD project: Diversity and Distribution of Amphipods in Switzerland

Amphipods are common and abundant crustaceans found worldwide. They constitute a crucial component of macroinvertebrate communities in aquatic ecosystems and contribute substantially to the functioning of the trophic relationships within aquatic systems. Although the ecological importance and widespread distribution is recognized, the actual diversity and distribution of amphipods is still understudied in many areas, particularly in Switzerland. For example, up to now there exists no detailed overview of all amphipod species from Switzerland, no identification keys and especially very little information on amphipods in alpine and higher elevation habitats. Additionally the biogeographical role of the Swiss Alps as origin of four major drainage areas in Central Europe is generally poorly understood and needs further investigations. A high degree of endemism can be observed in plants and animals, highlighting the importance and vulnerability of these habitats. The same can be expected in amphipods, but has hitherto not been validated. With my PhD project I aim to close these gaps.

G. alpinus from Lake Constance © Roman Alther


The contribution of tributaries to macroinvertebrate diversity in glacial catchments

Many glaciers on the globe have significantly receded during the
last decades in response to climate change. Most studies in this context have focused
on biotic assemblages in glacial-fed (kryal) streams, suggesting a high potential
loss in macroinvertebrate diversity in kryal streams as glacier-flow contributions
diminish. Alpine basins also comprise a large number of non-glaciated
(krenal, rhithral) streams likely inhabited by macroinvertebrate assemblages different
than those common to kryal streams. We examined macroinvertebrate assemblages
in 41 non-glacial tributaries within 5 different glacial catchments in the
Swiss Alps. The data were used to determine their contribution and role in the
overall biodiversity of glacial catchments. We found an astonishing high diversity
of macroinvertebrates in these tributaries with 64 taxa in 12 orders being identified
overall and up to 24 different taxa found at individual sites. The abundance,
taxonomic richness (α-diversity) and assemblage composition (β-diversity) differed
highly between tributaries, suggesting their role as habitat for non-glacial
specialists and as potential refugia for alpine species in general. The tributaries
showed high individuality in physico-chemical factors as well as in taxonomic
composition. Most of the taxa found could be defined as rare when comparing
abundances, highlighting the importance of an analytical approach including all
taxa. These results indicate that non-glacial tributaries contribute significantly to
the biodiversity of alpine running waters and may play an important role in sustaining
alpine biodiversity under landscape transformation resulting from climate