The future of soil invertebrate communities in polar regions: different climate change responses in the Arctic and Antarctic?

Abstract

The polar regions are experiencing rapid climate change with implications for terrestrial ecosystems. Here, despite limited knowledge, we make some early predictions on soil invertebrate community responses to predicted twenty-first century climate change. Geographic and environmental differences suggest that climate change responses will differ between the Arctic and Antarctic. We predict significant, but different, belowground community changes in both regions. This change will be driven mainly by vegetation type changes in the Arctic, while communities in Antarctica will respond to climate amelioration directly and indirectly through changes in microbial community composition and activity, and the development of, and/ or changes in, plant communities. Climate amelioration is likely to allow a greater influx of non-native species into both the Arctic and Antarctic promoting landscape scale biodiversity change. Non-native competitive species could, however, have negative effects on local biodiversity particularly in the Arctic where the communities are already species rich. Species ranges will shift in both areas as the climate changes potentially posing a problem for endemic species in the Arctic where options for northward migration are limited. Greater soil biotic activity may move the Arctic towards a trajectory of being a substantial carbon source, while Antarctica could become a carbon sink.

Pole-to-Pole Connections: Similarities between Arctic and Antarctic Microbiomes and Their Vulnerability to Environmental Change

“…Higher temperatures in the polar regions will probably directly influence microbial communities by an elongation of the growth season, the availability of freshwater and daily temperature cycles with less freeze-thaw events. Lower environmental filtering induced by climate change as described here may support the establishment of cosmopolitan taxa, capable of long-distance dispersal, over more specialized and endemic taxa and may support the invasion of species on other trophic levels which could impact benthic microbial biofilm biology and biodiversity (Nielsen and Wall, 2013). In the longer term it can be expected that multicellular organisms such as mosses and grasses will replace microbial primary producers in currently microbial dominated habitats (Convey et al, 2003;Biersma et al, 2017), with microbial-dominated communities increasingly restricted to the highest latitudes (Nielsen and Wall, 2013).…”

“…It has been proposed that climate change has already led to a weakening of biogeographic boundaries and the merging of ecological niches in the polar regions (Walther et al, 2002;Post et al, 2009;Nielsen and Wall, 2013;Pointing et al, 2015). The polar regions therefore provide a unique opportunity to test biogeographic patterns of microbial diversity, providing predictors/indications of the future consequences of environmental change.…”

The spatial structure of Antarctic biodiversity

“…However, temperature may still have important indirect influences, through its effects on the rate of snow-and ice-melt, and eventually, on soil moisture (Convey et al 2003, Clarke et al 2012). This implies that global climate change will have indirect effects on abundance and distribution through the modification of the normal water cycle in Antarctica, mediated by small-scale variation in water availability (Nielsen and Wall 2013). Recently, decadal time-scale climate changes have been recorded, along with occasional exceptional years , Doran et al 2002, Fountain and Lyons 2003, which can have longstanding effects on the soil biota (e.g., Barrett et al 2008).…”

Local and regional influences over soil microbial metacommunities in the Transantarctic Mountains

“…For example, community composition is more closely tied to habitat characteristics for good dispersers than dispersal-limited organisms (De Bie et al 2012), random drift in community composition is more likely in assemblages in stable habitats with high productivity (Chase 2007(Chase , 2010, and assemblages in high stress habitats (e.g., frequent drought, low productivity) are more likely to converge upon similar community compositions of tolerant taxa (Chase 2007). Understanding how ecological context influences local and regional controls over soil microbial diversity (Dumbrell et al 2009, Caruso et al 2011, Soininen 2012) is imperative for Antarctic soils because these relatively simple ecosystems may be particularly sensitive to climate change (Nielsen and Wall 2013). Antarctic soils are predicted to become warmer and wetter (Bracegirdle et al 2008), and an increased frequency of pulse melt/flood events (IPCC 2007) will likely alter the temporal and spatial distribution of liquid water, which can significantly affect soil ecological processes , Nielsen et al 2012, Nielsen and Wall 2013.…”

“…Understanding how ecological context influences local and regional controls over soil microbial diversity (Dumbrell et al 2009, Caruso et al 2011, Soininen 2012) is imperative for Antarctic soils because these relatively simple ecosystems may be particularly sensitive to climate change (Nielsen and Wall 2013). Antarctic soils are predicted to become warmer and wetter (Bracegirdle et al 2008), and an increased frequency of pulse melt/flood events (IPCC 2007) will likely alter the temporal and spatial distribution of liquid water, which can significantly affect soil ecological processes , Nielsen et al 2012, Nielsen and Wall 2013. Therefore, it is essential to resolve the influences of local and regional controls over soil microbial community composition, which may allow us to predict how Antarctic terrestrial ecosystems will respond to climatic shifts.…”