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Fine-Tuning the Spatial Distributions of Species' Thermal Habitats
Volume 16, Number 47: 20 November 2013

Lenoir, J., Graae, B.J., Aarrestad, P.A., Alsos, I.G., Armbruster, W.S., Austrheim, G., Bergendorff, C., Birks, H.J.B., Brathen, K.A., Brunet, J.O., Bruun, H.H., Dahlberg, C.J., Decocq, G., Diekmann, M., Dynesius, M., Aes, R.E., Grytnes, J.-A., Hylander, K., Anderud, K., Luoto, M., Milbau, A., Moora, M., Nygaard, B., Odland, A., Ravolainen, V.T., Reinhardt, S., Sandvik, S.M., Schei, F.H., Speed, J.D.M., Tveraabak, L.U., Vandvik, V., Velle, L.G., Virtanen, R., Zobel, M. and Svenning, J.-C. 2013. Local temperatures inferred from plant communities suggest strong spatial buffering of climate warming across Northern Europe. Global Change Biology 19: 1470-1481.

In introducing their intriguing new paper, Lenoir et al. state that "several models using the IPCC climate-change scenarios to forecast impacts on biodiversity predict that many organisms risk extinction within the next century." However, they indicate that "these models were computed at a coarse spatial resolution (>>1 km2) and fail to capture spatial variability in temperature over tens or hundreds of meters," which latter phenomenon can, in their words, "potentially constitute an important buffer in ecosystem response to climate change," citing Ackerly et al. (2010). In fact, they note that topo-climatic variability may provide "micro-refugia where species might persist locally amidst unfavorable regional conditions," as described by Dynesius et al. (2009), Ashcroft (2010), Austin and Van Niel (2011) and Dobrowski (2011), simply "by shifting by as little as a few meters to neighboring locations with cooler conditions," such as "towards more polar-facing slopes with lower insolation or towards patches of wetter ground with higher heat-consuming evaporation," as has been described by Edwards and Armbruster (1989), Wesser and Armbruster (1991), Armbruster et al. (2007) and Ackerly et al. (2010).

Focusing on Northern Europe (53-82°N, 3-32°E), the 35 researchers compiled a comprehensive database of 42,117 fine-grained (<1000 m2) and geo-referenced plots of terrestrial vascular plant communities that encompassed a large array of vegetation types, including forests, scrublands, grasslands and moorlands, after which they combined all vegetation plots with Ellenberg et al. (1992) species-indicator growing-season temperatures that ranged from 1 (cold) to 9 (warm) with independent data on field records of plant community composition, as had previously been done by Karlsen and Elvebakk (2003), Karlsen et al. (2005) and Scherrer and Korner (2011), which procedure they describe as "an approach that is particularly well suited for predictive purposes."

And when (at last!) all was done, Lenoir et al. concluded that "fine-grained thermal variability over tens or hundreds of meters exceeds much of the climate warming expected for the coming decades," which led them to further conclude that "thermal variability within 1-km2 units strongly increases local spatial buffering of future climate warming across Northern Europe, even in the flattest terrains," while indicating once again that this variability in temperature "provides buffering to mitigate climate-change impacts."

Sherwood, Keith and Craig Idso

Ackerly, D.D., Loarie, S.R., Cornwell, W.K., Weiss, S.B., Hamilton, H., Branciforte, R. and Kraft, N.J.B. 2010. The geography of climate change: implications for conservation biogeography. Diversity and Distributions 16: 476-487.

Armbruster, W.S., Rae, D.A. and Edwards, M.E. 2007. Topographic complexity and biotic response to high-latitude climate change: variance is as important as the mean. In: Orbaek, J.B., Kallenborn, R., Tombre, I., Hegseth, E.N., Falk-Petersen, S. and Hoel, A.H. (Eds.). Arctic-Alpine Ecosystems and People in a Changing Environment. Springer Verlag, Berlin, Germany.

Ashcroft, M.B. 2010. Identifying refugia from climate change. Journal of Biogeography 37: 1407-1413.

Austin, M.P. and Van Niel, K.P. 2011. Improving species distribution models for climate change studies; variable selection and scale. Journal of Biogeography 38: 1-8.

Dobrowski, S.Z. 2011. A climatic basis for microrefugia: the influence of terrain on climate. Global Change Biology 17: 1022-1035.

Dynesius, M., Hylander, K. and Nilsson, C. 2009. High resilience of bryophyte assemblages in stream-side compared to upland forests. Ecology 90: 1042-1054.

Edwards, M.E. and Armbruster, W.S. 1989. A steppe-tundra transition on Kathul Mountain, Alaska. Arctic and Alpine Research 21: 296-304.

Ellenberg, H., Weber, H.E., Dull, R., Wirth, V., Werner, W. and Paulissen, D. 1992. Zeigerwerte von Pflanzen in Mitteleuropa. Scripta Geobotanica 18: 1-248.

Karlsen, S.R. and Elvebakk, A. 2003. A method using indicator plants to map local climatic variation in the Kangerlussuaq/Scoresby Sund area, east Greenland. Journal of Biogeography 30: 1469-1491.

Karlsen, S.R., Elvebakk, A. and Johansen, B. 2005. A vegetation-based method to map climatic variation in the arctic-boreal transition of Finnmark, north-easternmost Norway. Journal of Biogeography 32: 1161-1186.

Scherrer, D. and Korner, C. 2011. Topographically controlled thermal-habitat differentiation buffers alpine plant diversity against climate warming. Journal of Biogeography 38: 406-416.

Wesser, S.D. and Armbruster, W.S. 1991. Controls over species distribution across a forest-steppe transition: a causal model and experimental test. Ecological Monographs 61: 323-342.