气候变化领域集成服务门户

Across arid landscapes, desert shrubs affect where and how sediment is transported by various physical processes such as overland flow, wind, and rain splash. Simplistic biological models such as logistic growth curves offer important first steps towards representing and linking life to landscape dynamics. More sophisticated descriptions of desert shrub dynamics on scales commensurate with downslope sediment transport, however, are essential for more rigorously understanding how complex shrub-sediment interactions may be affecting hillslope geomorphology. Here we present such a model that features a strong biophysical foundation by including, for example, basic aspects of desert soil-water hydrology and population ecology such as recruitment, growth, and mortality. Model input parameters can also be modified to account for the influence of different environmental conditions and stressors (e.g. precipitation, soil types, droughts, grazing, fires, and climate change). Model behaviors mimic well documented aspects of how desert shrub populations respond to changes in precipitation, for example, productivity decreases with increasingly arid conditions and density declines during prolonged periods of drought. Model output (position and size of shrubs occupying a hillslope in a given year) represents the basic biological input variables necessary for calculating, for example, how rain-splash induced mound building by individual shrubs may be affecting downslope sediment fluxes. Future research aimed at coupling this biological model with existing sediment transport models can therefore help advance our understanding for how desert shrub populations affect hillslope erosion across a broad range of scenarios. (c) 2018 John Wiley & Sons, Ltd.