Response of plants and the dominant microarthropod,Cryptopygus antarcticus, to warming and contrasting precipitation regimes in Antarctic tundra

Abstract

We examined the influence of warming and supplemental precipitation on plant production and abundance of the dominant microarthropod, the springtail Cryptopygus antarcticus (Collembola), in tundra dominated by the vascular plants Colobanthus quitensis and Deschampsia antarctica along the Antarctic Peninsula. Tundra cores were placed in plots near Palmer Station where they were warmed with infrared heaters in combination with receiving supplemental precipitation. Diel canopy air and soil temperatures and air vapor pressure deficits in warmed plots were elevated 0.8 1C, 2.2 1C and 0.13 kPa, respectively. After two growing seasons, total aboveground plant production was greater under warming as a result of enhanced production by C. quitensis, which more than offset declines in moss biomass. Total aboveground plant production was also greater under supplemental precipitation primarily as a result of enhanced moss production. Total aboveground plant production was greatest under the combination of warming and supplemental precipitation, primarily as a result of enhanced C. quitensis production. C. antarcticus were more abundant in cores receiving supplemental precipitation and there was a strong treatment interaction; these springtails were most abundant in warmed cores receiving supplemental precipitation. Over 50% of the variability in the abundance of C. antarcticus could be explained by differences in aboveground plant biomass. However, plant production did not appear directly responsible for differences in C. antarcticus abundance; when we examined C. antarcticus abundance per unit of aboveground plant biomass, differences in its abundance among treatments were still apparent implying these differences were not the direct result of plant biomass. The responses of C. antarcticus were consistent with its known moisture and thermal preferences, suggesting that abiotic factors played a dominant role in controlling its abundance. Precipitation regime had large impacts on warming responses and these were species specific, illustrating the importance of future precipitation regimes in predicting system responses to warming.

Temperature-based bioclimatic parameters can predict nematode metabolic footprints

“…Soil fungi are more tolerant than bacteria to temperatures that are above optimum (Barcenas-Moreno et al 2009) and appear to increase their activity after a long-term increase of temperature, as indicated by fruit body production (Gange et al 2007). Organisms feeding on fungi are also more tolerant to elevated temperatures (Stamou and Sgardelis 1989;Maraun et al 2007) and increase in abundance when moisture is not a limiting factor (Day et al 2009;Kardol et al 2010). In general organisms belonging to the fungal-based food web channel have been found to be more resistant and better able to adapt to climate change associated with drought (de Vries et al 2012).…”

Reproductive output of mosses under experimental warming on Fildes Peninsula, King George Island, maritime Antarctica

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Passive warming reduces stress and shifts reproductive effort in the Antarctic moss,Polytrichastrum alpinum

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