Biodiversity increases and decreases ecosystem stability

Experiments have shown that biodiversity may increase or decrease ecosystem stability. As part of a collaboration between Owen Petchey’s lab at University of Zurich and Florian Altermatt’s lab at Eawag, we performed a large experiment that showed that species richness can simultaneously increase and decrease ecological stability. This highlighed that one should consider multiple stability components and that this could provide new insights. The study was recently published in Nature (read article here) and I am proud to be part of this fruitful project. The story behind the paper can be read in this blog post by Frank Pennekamp.

An endemic amphipod of the Alps

Endemic_amphipod_Gammarus_alpinus
Gammarus alpinus from Lej da Silvaplauna (Switzerland)

In our most recent paper, Florian Altermatt, Cene Fišer, and me describe a new  amphipod species that is endemic to the Alps. What has been considered to belong to the circumboreal Gammarus lacustris species complex turned out to be a highly diverged lineage. It represents an own species within the Alps. Given its natural but restricted distribution, we name the endemic amphipod species Gammarus alpinus sp. nov.

Already endangered?

The species is commonly found in high alpine lakes of Central Europe. Although its wide distribution, invasive species and increasing anthropogenic pressure in its natural habitat impose challenges to the newly described species. Assigning a name to this biological entity hopefully facilitates the conservation efforts. Our study is published in the Zoological Journal of the Linnean Society. It highlights the importance of combining different methods to resolve cryptic diversity. Furthermore I would hereby like to acknowledge all the people and institutions that helped to conduct this study.

Alpine chironomids of Switzerland

Lang

Our study on chironomids of high elevation and non-glacial streams is available online via Schweizerbart. We found highly diverse and spatially-structured communities of these ecologically important macroinvertebrates. Rarity was prevalent and highlighted the local differences between sites. Regional patterns reflected distributions of the more common taxa. Hence, projections of chironomid assemblages under climate warming are difficult and conservation of these diverse habitats is therefore important.

Amphipod communities in tributaries to Lake Constance

LakeConstance

Work that initially started as a small semester project in 2011, thought to provide a better understanding of amphipod communities in streams around Lake Constance, now got published in BMC Ecology. I’m really happy that Florian Altermatt suggested this project when I started my Master’s studies and that his research group continued to work on the study system. The project introduced me to the world of amphipods and this is how I eventually became an amphipodologist.

In the paper, we report replicated patterns of community composition and spatial distributions in smaller tributary streams of Lake Constance. However, invading species had no clear effect on the genetic diversity of native amphipods on this small spatial scale. This suggests that large scale observations of invasion biology may not be directly reflected on a smaller scale.

An insight into foodwebs of alpine streams

WindRiverRange_Stream

Finally, the latest paper I was involved during my Masters got released: “A note on the trophic structure of alpine streams in the Wind River Mountains, Wyoming, USA” in Fundamental & Applied Limnology. The results suggest a glacial carbon signature in stream foodwebs close to the glacier. Further a longitudinal shift in carbon sources was observed in these streams, from a glacial to an instream source and finally to a allochthonous source when moving along the system. Thanks again to the whole team. Riding to the remote sites and sampling was great fun and an exciting adventure.