The influence of geomorphic processes on plant distribution and abundance as reflected in plant tolerance curves

Ecologists describe plant distribution using direct gradient analysis, by which a tolerance curve of species abundance is described along an environmental gradient (any environmental variable that affects plant distribution). Soil moisture is generally the gradient in low relief areas that explains the most variation. Traditional direct gradient analyses have used terrain structure (i.e. transects up or down hillslopes) as a correlate to soil moisture. Here we use a numerical tectonic and geomorphic process-based landscape development model to create two landscapes with different geomorphic characteristics (i) to demonstrate the influence of geomorphic processes on soil moisture patterns and plant distribution and (ii) to evaluate the effectiveness of transects in describing moisture gradients and tolerance curves on landscapes dominated by creep or overland flow. We use a topographic index to approximate the distribution of soil moisture as it is determined by the shape of these differ...