Can climate change in extreme ecosystems inform future scenarios of soil biodiversity

Background/Question/Methods

Terrestrial ecosystems of the Polar Regions and hot deserts are extreme in terms of temperature and moisture. The Arctic (cold, wet), Antarctic (cold, dry) and temperate deserts (hot, dry) however, differ dramatically in plant productivity, decomposition rates and soil biodiversity. We questioned if the structure and activity of soil communities were dependent more on habitat suitability (i.e. soil chemical and physical properties, presence of plants), climate or biotic interactions. We considered how responses of soil biota to climate changes across these ecosystems could inform us about future scenarios for soil biodiversity and biogeochemical processes at regional to global scales. The McMurdo Dry Valley, Antarctica (MCM) and the Jornada (JRN) LTERs are deserts with alkaline soils, high heterogeneity of soil properties, low soil moisture but extremes in temperatures.

Results/Conclusions

In the MCM, soil physical and chemical factors determine suitable habitats and the distribution and diversity of soil invertebrates, whereas plant factors exert a dominant influence on soil biota in warm deserts. The MCM landscape is dominated by 1 species, Scottnema lindsayae, which declines with increasing soil moisture. For example, a season of increased temperature resulted in water flow across the landscape, altering habitats and populations of S. lindsayae. In hot deserts, soil diversity is more complex, with more nematode species that follow patchy plant distribution and root depths (>1m); but with desertification, patchiness increases and soil species richness declines. The cold, wet tundra has higher diversity of soil invertebrates with soil habitats defined by a more homogenous plant distribution and higher levels of soil organic matter. There, warming alters soil moisture and plant dynamics, which impacts soil animals, but the direction of change is difficult to predict. Our MCM and JRN data indicate that changes in soil temperature and moisture affect soil habitat suitability, whether through alteration of soil properties or plant factors, thus influencing the distribution and diversity of soil animals. We conclude that climate change in extreme ecosystems alters soil habitat suitability and has immediate impacts on soil species, changes that are less discernable in ecosystems of high soil animal diversity.