Event

Abstract: Desert ecosystems have been characterized by Noy-Meir (1973) as "water-controlled ecosystems with infrequent, discrete and largely unpredictable water inputs," with the limiting resource of water arriving in short-lived pulses. These dry climates are known to support regular, large-scale patterns of vegetation growth organized into evenly spaced bands that are separated by swaths of bare soil, and studies suggest that this may provide improved resilience to drought. I will present a modeling framework for vegetation pattern formation in drylands that treats storms as instantaneous kicks to the soil water, which then interacts with vegetation during the long dry periods between the storms. The spatial profiles of the soil water kicks capture positive feedbacks in the storm-level hydrology that act to concentrate water within the vegetation bands. This flow-kick model predicts that variance in rainfall introduced through randomness in the timing and magnitude of water input from storms decreases the parameter range over which patterns appear and may therefore negatively impact ecosystem resilience.