Blown Away: Extreme Wind Events Impact Grass Mortality

Abstract

Understanding extremes in ecological change is critical given the anticipated increasing frequency of such events. This is especially true when extreme events trigger transitions to alternative stable states, as in drylands that have seen conversion from grass- to shrub-dominated states. We examined the responses of a Chihuahuan Desert community after record winds in 2019 killed grasses and reduced greenness. We argue that wind has two faces like Janus, aptly the Roman god of transitions, because it participates in change as both a forcing and a feedback and that, similarly, other types of extremes can alter the character of ecological interactions. Photo 1. Record-breaking wind in southern New Mexico in the spring of 2019 had major impacts on grass at the Jornada Long Term Ecological Research site in Las Cruces, New Mexico. The exposed roots of two Sporobolus spp. grasses are a result of these storms. Photo credit: G.S. Okin. Photo 2. In some cases, grasses, like the one on the left in this image, were able to green up following rain in the early summer. Other grasses appear to have been killed by the root exposure and sandblasting that occurred during the extreme wind events in the spring of 2019. Photo credit: G.S. Okin. Photo 3. UCLA undergraduate, Sarah Payne (shown here indicating the extent of root exposure on a native bunchgrass), conducted an NSF-supported summer research project that resulted in a publication of an article in Ecology. Photo credit: G.S. Okin. These photographs illustrate the article “The two faces of Janus: Processes can be both exogenous forcings and endogenous feedbacks with wind as a case study” by Sarah A. R. Payne, Gregory S. Okin, Abinash Bhattachan, and Michael R. Fischella published in Ecology. https://doi.org/10.1002/ecy.3998