We are community ecologists in a wide sense. We would like to understand how species occur in space and time, how dispersal and landscape structure affect community composition and diversity and how processes such as climate change or species invasions affect dynamics within and between communities.
Our research is centered around the following questions:
- How do spatial dynamics affect biodiversity and ecosystem functioning?
- How are species interactions affected by global changes?
- How to fundamentally assess biodiversity using environmental DNA (eDNA)?
Spatial Ecology and Meta-ecosystems
Ecosystems are not isolated, but are commonly connected via flows of non-living materials (e.g., detritus, nutrients) and the movement of living organisms. As posited by the meta-ecosystem framework, these connections between ecosystems mean that the properties of one ecosystem—such as its community composition, biomass structure, or functions—can influence the ecosystem it is connected to. Likewise, such connections mean that ecological change in one ecosystem can spatially cascade to impact the properties of different ecosystems.
Our group aims to develop our understanding of meta-ecosystem dynamics through a combination of mathematical models, experiments, and field observations. We develop mathematical models and use protist experiments to make and test predictions on the impacts spatial flows between ecosystems have on biodiversity and ecosystem functions in a changing world. Further, we study naturally replicated forest-headwater stream meta-ecosystems to characterize the spatial and temporal characteristics of spatial flows, how they are changing across seasons and how they shape decomposer communities, with a focus on amphipods.
Key papers:
- Gounand, I., E. Harvey, P. Ganesanandamoorthy and F. Altermatt (2017). “Subsidies mediate interactions between communities across space.” Oikos 126: 972-979.
- Gounand, I., C. J. Little, E. Harvey and F. Altermatt (2018). “Meta-ecosystems 2.0: rooting the theory into the field.” Trends in Ecology & Evolution 33: 36–46.
- Peller, T. and F. Altermatt (2024). “Invasive species drive cross-ecosystem effects worldwide.” Nature Ecology & Evolution 8: 1087–1097.
- Peller, T., I. Gounand and F. Altermatt (2024). “Resource flow network structure drives meta-ecosystem function.” American Naturalist 204:.
Environmental DNA to assess biodiversity
All organisms shed DNA into their environment. This so-called environmental DNA (DNA) can be collected and extracted. Using molecular advancements, we sequence eDNA to gain biodiversity information – from microbes to mammals – characterizing organismal communities and whole food webs. As a group, we have made fundamental contributions in the development and application of eDNA to assess biodiversity in aquatic ecosystems.
Our work covers a broad range of eDNA research from nationwide invasive species detection to constructing interaction networks, predicting biodiversity across riverine networks and exploring hard to study ecosystems, such as groundwater. We are also interested in exploring fundamental questions of eDNA by modeling the origin, transport and fate of biodiversity signals within large river networks. Alongside our combined research interests, we play a key role in the development and end-user uptake of eDNA techniques. By collaborating at the local, national and international scale, we have contributed to national guidelines, DNA methodological handbooks and run workshops to offer guidance and aid the implementation of eDNA for biomonitoring.
Key papers:
- Carraro, L., E. Mächler, R. Wüthrich and F. Altermatt (2020). “Environmental DNA allows upscaling spatial patterns of biodiversity in freshwater ecosystems.” Nature Communications 11: 3585.
- Keck, F., R. C. Blackman, R. Bossart, J. Brantschen, M. Couton, S. Hürlemann, D. Kirschner, N. Locher, H. Zhang and F. Altermatt (2022). “Meta-analysis shows both congruence and complementarity of DNA and eDNA metabarcoding to traditional methods for biological community assessment.” Molecular Ecology 31: 1820–1835.
- Blackman, R. C., H.-C. Ho, J.-C. Walser and F. Altermatt (2022). “Spatio-temporal patterns of multi-trophic biodiversity and food-web characteristics uncovered across a river catchment using environmental DNA.” Communications Biology 5: 259.
- Zhang, H., E. Mächler, F. Morsdorf, P. A. Niklaus, M. E. Schaepman and F. Altermatt (2023). “A spatial fingerprint of land-water linkage of biodiversity uncovered by remote sensing and environmental DNA.” Science of The Total Environment 867: 161365.
Biodiversity of freshwater amphipods
Amphipods are key organisms in freshwater ecosystems and commonly used as indicator taxa for biomonitoring and ecotoxicology. We study the diversity, biogeography and ecology of freshwater amphipods, with a focus on the European Alps/Switzerland. We thereby integrate knowledge on natural history, taxonomy and spatial distribution of surface and groundwater amphipods to understand how their contemporary species and genetic diversity have been shaped by macroecological and anthropogenic drivers.
In the project Amphipod.CH we have established the first complete overview of all 60+ species of amphipods in Switzerland. In long-term replicated stream catchments, we are studying how community structure and turnover is shaped by terrestrial land-use and species interactions, and linking amphipod occurrence to leaf litter decomposition and overall ecosystem functioning. In the project AmphiWell, we study the diversity of groundwater amphipods, combining innovative citizen-science, eDNA approaches and advanced molecular tools to understand the diversity and distribution of groundwater fauna. We thereby have discovered and described many species of Niphargus as new to science. Many of these endemic species are glacial relicts predating late Pleistocene glaciation and part of Switzerland’s natural heritage.
Key papers:
- Alther, R., E. A. Fronhofer and F. Altermatt (2021). “Dispersal behaviour and riverine network connectivity shape the genetic diversity of freshwater amphipod metapopulations.” Molecular Ecology 30: 6551–6565.
- Couton, M., S. Hürlemann, A. Studer, R. Alther and F. Altermatt (2023). “Groundwater environmental DNA metabarcoding reveals hidden diversity and reflects land-use and geology.” Molecular Ecology 32(13): 3497–3512.
- Cereghetti, E. and F. Altermatt (2023). “Spatiotemporal dynamics in freshwater amphipod assemblages are associated with surrounding terrestrial land use type.” Ecosphere 14(3): e4469.
- Knüsel, M., R. Alther and F. Altermatt (2024). “Pronounced changes of subterranean biodiversity patterns along a Late Pleistocene glaciation gradient.” Ecography 2024: e07321.