Recent elevated temperatures and prolonged droughts in many rangelands throughout the world are likely to intensify according to future climate-model projections. This warming and drying can negatively affect the establishment and growth of perennial vegetation and lead to restoration failures. To better forecast these detrimental effects, we formulate a conceptual model of rangeland vulnerability to enhanced aridity that integrates hypotheses on plant species responses to reductions in water availability and how these responses are modified by biophysical attributes, including landscape, soil and plant properties. We test the model by integrating long-term monitoring results across the southwestern U.S. and employing a novel �climate pivot point� approach. Plant species, communities, and ecoregions ranged in their sensitivities to precipitation in different seasons, capacities to increase in abundance during wet conditions, and resistances to drought. Our model successfully explains how plant responses to climate are moderated by biophysical attributes. For example, deep-rooted plants were not as vulnerable to drought on soils that allowed for deep-water percolation, whereas shallow-rooted plants were better buffered from drought on soils that promoted water retention near the surface. Our results imply that multiple biophysical attributes of a site should collectively be considered in restoration planning because they mediate the performance of plant species through their influence on water availability and use.
Oral presentation and poster titles, abstracts, and authors from the Society for Range Management (SRM) Annual Meetings and Tradeshows, from 2013 forward.