Climate and vegetation drivers of the soil food web along elevational gradients in northern Arizona

The soil food web carries out processes (e.g. decomposition) vital to terrestrial life. Climate and vegetation are important drivers of the soil food web, and thus can affect these processes through the soil food web. Understanding the tripartite relationship between climate, vegetation, and the soil food web has proven difficult due to the existence of multiple ways to represent these factors (for example, approximating climate through temperature and precipitation), and the indirect effects of climate on the soil food web manifested through vegetation. To better understand the specific effects of climate and vegetation in soil food web composition and function, it is essential to: understand the relative effect strengths of drivers (i.e. climate and vegetation) on the soil food web, partition direct and indirect effects of climate, and do so with different representations of soil food web composition (i.e. taxa vs functional groups).;Two elevational gradients in northern Arizona were sampled for vegetation and soil fauna, and long term climate data compiled to investigate the effects of climate and indirect effects of vegetation on the soil food web. Taxa varied considerably in response to elevation while functional groups remained relatively similar. Direct climate associations with the soil food web were 4-fold greater than indirect associations through vegetation. In addition, the soil food web responded differently if characterized as taxa or functional groups, with taxa correlating 3 times more strongly with climate and having ten times the variation explained by predictor variables than functional groups. These results indicate that climate change will exert strong direct effects on soil taxa, but functional groups (and by extension, processes) will be relatively stable.