Rainfall-tuned management facilitates dry forest recovery

Regeneration of original dry forests and shrublands in degraded arid and semiarid ecosystems can be a slow and difficult process. It has been hypothesized that restoration efforts during periods of increased water availability may potentially trigger shifts back to a high vegetation cover depending on several environmental factors that govern the response of vegetation to rainfall. Tuning restoration efforts to climate variability will likely become increasingly important under climate change conditions. The experiences evaluated here are a pioneering effort to reforest arid South American forests. We used a combination of field monitoring and remote sensing images to evaluate the long-term effects of seeding and herbivore control in local reforestation projects tuned to the forecasted rainy El Niño Southern Oscillation (ENSO) events of 1991/1992 and 1997/1998 in North Peru and to assess the regional response of vegetation to these rainy events at a regional scale. We found that managing seed availability in combination with seedling protection from herbivores only yielded persistent higher vegetation cover when implemented on sites without calcareous layers and relatively high water availability determined by the surrounding topography. Our study shows that management tuned to forecasted rainfall events is able to trigger a long-lasting shift toward higher vegetation cover. We provide a better insight in how environmental factors shape vegetation response to increased rainfall and discuss the implications for ecosystem resilience and restoration.