Estimating Climate-Induced Change in Soil Moisture at the LandscapeScale: An Application to Five Areas of Ecological Interest in the U.K.

Abstract

This paper presents an indication of the possible effects of climate change on monthly mean soil moisture at a fine spatial resolution (50 m) over the scale of a landscape (100–250 km2). Soil moisture is modelledusing daily time series of rainfall and potential evapotranspiration to drive a simple hydrological model operating on individual hillslopes and explicitly including, on a conceptual level, the lateral movement of water. Climate change is represented by the UKTR scenario and model results are provided at two time slices (the years 2030–2040 and 2060–2070) for five areasof ecological interest, forming a north-south transect across the U.K. The results are given in terms of the distribution of the monthly mean soil moisture change by soil type. The spread of values reflects the effect of the topographic control on the lateral movement of water. The results show a small increase in wetness at the Cairngorm site, a very slight decrease in summer soil moisture at the Moor House site and a very marked fall in soil moisture for the three more southerly sites. The importance of soil type in determining the availability of water to plants, the changing areal extent above specified soil moisture thresholds, and the implications for ecological change and conservation are discussed.