Taskforce 3

Education & Research Units

 

Climate & Environmental Change

 

Food, Environment & Health

 

Natural Hazards & Risks

 

Natural Resources

 

Sustainable Land Use

 

Integrative Elements

 

Research Platforms

 

Scientific Services

 

Education & Outreach

 

Aquatic ecosystem in an Alpine environment

Groups with experience on alpine aquatic systems (Seehausen and Jokela) will identify parallel systems on different trophic levels of aquatic systems. More specifically, we propose to focus on adaptive diversity expressed in alpine fish (Seehausen) and their prey (Jokela).  Key fish species in alpine habitats, the brown trout (Salmo trutta) and alpine bullheads (Cottus cobio), and the whitefish (Coregonus spp.) of pre-alpine habitats have contrasting phylogenetic histories and contrasting genetic structure.  Trout and bullhead have circum Alp distributions and inhabit a similarly wide range of thermal environments, from relatively warm lowland rivers to cold alpine streams.  Thus, populations of both species are exposed to the same range of thermal selection regimes.  However, the phylogeographies of the species are markedly different.  Brown trout form distinct genetic lineages with unique evolutionary histories in each of the four major Alp drainages (Rhone, Rhine, Danube and Po), but often display relatively little genetic structure at smaller spatial scales.  Alternatively, bullhead show a high degree of genetic differentiation at the local scale yet overall genetic diversity is distributed quite evenly within and between the major drainages.  Whitefish in contrast occupy only the narrow thermal belt of the pre-alpine rivers and lakes between 250 and 800m above sea level.

Their phylogeography is different from both trout and bullhead: they display strong genetic structure at small spatial scales and sympatric ecotype formation, but large scale admixis of glacial refugial lineages at the level of drainage systems. The three species also have different management histories.  Whereas brown trout and whitefish have a long history of inter- and intrabasin transplantation, bullhead have been relatively unaffected by anthropogenic interference.  Because the three species represent extremes along the population structure continuum and along a natural/anthropogenic continuum, information on the distribution of adaptive diversity across thermal gradients in brown trout, bullhead and whitefish will be transferable to a wide range of fish species.
 Main groups of invertebrates that are suitable prey for fish in alpine systems are large zooplankton (e.g. Daphnia), Amphipods, Isopods and Gastropods.  Genetic structure of gastropods resemble that of alpine plants (they are hermaphroditic, and capable of self-fertilization), but little is know about the genetic structure of amphipods and isopods.  Because the mating systems of these groups differ, but they occupy same habitats, they represent good model systems to contrast the adaptive potential of the species with respect to documented environmental change.  Also, the groups differ by their basic habitat requirements (broad tolerance water chemistry by isopods vs. specific requirements by amphipods; good drought tolerance of gastropods vs. sensitivity of isopods; good temperature tolerance of gastropods, vs. relatively higher sensitivity of amphipods), which all should reflect on the genetic diversity of the natural populations.