Standing crop of an abundant grass species is not affected by rainfall intensity

Köchy, M., F. Jeltsch

Some climate change scenarios predict that the frequency of intense rainstorms in the eastern Mediterranean will change. We used a process-based, spatially explicit model of soil moisture and the annual grass Avena sterilis to study potential effects of climate change on this species. A. sterilis is dominant or abundant in natural vegetation in semiarid and Meditarranean parts of Israel. We used historic precipitation records for five sites (representing aridity classes) and increased or decreased rainstorms >10 mm by 10%. Since soil texture covaries with the aridity gradient in Israel, we also investigated whether soil texture interacts with climate change effects. An ANCOVA with annual rainfall as covariate indicated that mean biomass varied significantly with the interaction of soil texture, aridity position, and change of rainstorm intensity. Differences of least square means among rainstorm intensities (range 2g/m2), however, were much smaller than those among five aridity classes (40 g/m2) or five soil texture classes (range 39 g/m2). Apparently, this abundant species is not likely to be affected by the assumed changes in frequency of rainfall intensity.

90. Annual Meeting of the Ecological Society of America and IX International Congress of Ecology. Montréal, Québec (Canada).