One of the classic state-change stories is that over-grazing and drought turn grasslands into shrubby, degraded landscapes. Land managers strive to avoid such irreversible changes, using strategies based on models of how ecosystems change. But misapplication of models can lead to poor management outcomes. Researchers at the Jornada Basin LTER site and its host the USDA Jornada Experimental Range have developed a new model of desert grassland ecosystem dynamics that is grounded in long-term data and experiments indicating possible trajectories. Even after abrupt vegetation change, gradual recovery appears to be possible–sometimes along unexpected pathways–as long as critical thresholds in species abundance and soil erosion rates are not crossed.
Brandon Bestelmeyer, USDA-Agricultural Research Service, Jornada Basin LTER