Drought stress and vegetation characteristics on dune slopes

“Droughts will affect vegetation characteristics, which may for instance influence the groundwater recharge rates and the availability of fresh water for e.g. agriculture and drinking water. To anticipate changes in climatic conditions, we need to be able to predict possible vegetation responses to increased drought conditions. In this paper, we introduce an ecologically relevant measure of drought stress and its relationship with vegetation characteristics.
Drought stress depends on soil type and climatic conditions. The effect of the latter can be observed by differences in vegetation characteristics on surfaces with different slope and aspect, where received solar radiation determines the spatial variability in vegetation characteristics due to spatially variable drought conditions. Solar radiation is a key determinant of vegetation characteristics, not only at large spatial scales, but also at local scales where slope and aspect may vary. Higher solar radiation on equator-facing slopes relative to polar-facing slopes results in a higher evaporative demand, and, consequently, drier soils. As a consequence of such dry conditions, the vegetation on equator facing surfaces is more xeric, has a lower aboveground biomass and plant cover, and is more patchy than on polar facing surfaces.”

(Citaat: Bartholomeus, R.P., Witte, J.P.M., Runhaar, J. – Drought stress and vegetation characteristics on dune slopes: Sand dune and shingle network – Fourteenth Newsletter (2012) April)