Effects of climate and aquatic prey on spider ecology in subarctic mountain tundra

Climate change is causing northward expansions of many species, which may change species interactions and rewire food webs.

In tundra-like ecosystems, which are experiencing strong effects of climate change, spiders play a dominant role in arthropod communities.

Yet, we have little knowledge of how they will respond to climate change, and therefore how the whole arthropod community is affected.

For many spider species, high prey availabilities typically occur around water bodies, which are associated with high abundances of flying insects that have aquatic life stages, commonly referred to as aquatic subsidies. This is also the areas where spiders that expand their range northwards are likely to establish first.

This project aims to determine how spiders, and the trophic interactions that they are involved in, are affected by distances to water bodies along an elevational climate/productivity gradient.

We will sample arthropods in a Swedish mountain habitat and use genetic metabarcoding methods to determine community composition and trophic links involving spiders, and how they change with elevation and aquatic subsidy availability.

Based on our results we will quantify how resilient those food webs are to irregularities in subsidy regime based on simulations.

The results will clarify how climate affects a key predator in an important ecosystem type, knowledge that will have implication for management, but also be generalisable to other ecosystems.