Species and community responses to short‐term climate manipulation: Microarthropods in the sub‐Antarctic

Abstract

Both species and community-level investigations are important for understanding the biotic impacts of climate change, because current evidence suggests that individual species responses are idiosyncratic. However, few studies of climate change impacts have been conducted on entire terrestrial arthropod communities living in the same habitat in the southern Hemisphere, and the effects of precipitation changes on them are particularly poorly understood. Here we investigate the species-and community-level responses of microarthropods inhabiting a keystone plant species, on sub-Antarctic Marion Island, to experimental reduction in precipitation, warming and shading. These climate manipulations were chosen based on observed climate trends and predicted indirect climate change impacts on this system. The dry-warm and shade inducing treatments that were imposed effected significant species-and community-level responses after a single year. Although the strongest community-level trends included a dramatic decline in springtail abundance and total biomass under the dry-warm and shade treatments, species responses were generally individualistic, that is, springtails responded differently to mites, and particular mite and springtail species responded differently to each other. Our results therefore provide additional support for the dynamic rather than static model for community responses to climate change, in the first such experiment in the sub-Antarctic. In conclusion, these results show that an ongoing decline in precipitation and increase in temperature is likely to have dramatic direct and indirect effects on this microarthropod community. Moreover, they indicate that while at a broad scale it may be possible to make generalizations regarding species responses to climate change, these generalizations are unlikely to translate into predictable effects at the community level.

A physiological trait‐based approach to predicting the responses of species to experimental climate warming

“…Predicting biological responses to climate change is critical (Arau´jo et al 2005), but a number of researchers have begun to emphasize the potential unpredictability of species' responses to climate change (e.g., Hill et al 2002, McGeoch et al 2006, Pelini et al 2009, Doak and Morris 2010. If species-specific traits covary with their responses to climate change, such traits can be used to predict community change (Diamond et al 2011, Angert et al 2011.…”

The Prince Edward Islands: Land-Sea Interactions in a Changing Ecosystem

“…This species is well suited for an examination of spatial variation because it is abundant and widely distributed on the island, plants have a discrete physical boundary, and are host to several other plant and invertebrate species. Furthermore, A. selago has been the focus of a research programme aimed at understanding not only spatial variation in the terrestrial system, but also the likely impact of climate change on the biota of Marion Island (Hugo et al 2004;le Roux 2004;le Roux & McGeoch 2004;le Roux et al 2005;McGeoch et al 2006;). Here we explore variation in this species, and the epiphytes and arthropods associated with it, within and across three spatial scales: (i), fine scale patterns within individual plants (plant scale), (ii) mesoscale variation across stands or patches of plants (landscape scale) and (iii) island-wide variation associated with the altitude gradient on the island and island aspect (the island scale).…”

“…sPaTial variaTion in The TerresTrial bioTic sysTem Spatial variation in A. selago thus has a considerable effect on the structure, composition and functioning of fellfield ecosystems, that constitute approximately half of Marion Island's surface area . Therefore, documenting and understanding this variation is important, and increasingly so given the rapid rates of environmental change on the Prince Edward Islands Chown et al 2001;le Roux et al 2005;McGeoch et al 2006;.…”

“…Given that few studies have been set up to do the former (and even these may fail given inappropriate time scales -see above), and the difficulty of overcoming the latter, understanding of climate change effects at this level are some way away. Nonetheless, judicious mesocosm-type studies and ethical manipulative field experiments (le Roux et al 2005;McGeoch et al 2006) may provide the required insights.…”

Conclusion: change in terrestrial and marine systems

“…Thus, invasive species show an improvement in desiccation resistance when exposed to high temperatures, whereas the converse is true of the indigenous species. This may account for the substantial declines in abundance of most of the indigenous species, but little change in the abundance of the invasives, in response to simulated warming and drying (McGeoch et al 2006). …”