Temperature drives seagrass recovery across the Western North Atlantic

Climate-driven shifts in herbivores, temperature and nutrient runoff threaten coastal ecosystem resilience. However, our understanding of ecological resilience, particularly for foundation species, remains limited due to a rarity of field experiments that are conducted across appropriate spatial and temporal scales and that investigate multiple stressors. This study aimed to evaluate the resilience of a tropical marine plant (turtlegrass) to disturbances across its geographic range and how this is impacted by environmental gradients in abiotic and biotic factors. We assessed the resilience (i.e. recovery) of turtlegrass to a simulated disturbance (complete above- and belowground biomass removal) over a year. Contrary to temperate studies, higher temperature generally enhanced seagrass recovery. While nutrients and light availability had minimal impact, combined high levels of nutrients and herbivore grazing (meso and megaherbivore) reduced aboveground recovery. Our results suggest that the resilience of some tropical species, especially in cooler subtropical waters, may initially increase with warming.

Methods
This dataset contains the data collected from field experiments studying the impact of fertilization treatments and environmental drivers on the recovery rate of the (sub)tropical seagrass species Thalassia testudinum. In this study, we experimentally disturbed plots of seagrass by removing all above and below ground biomass within a 15 cm diameter circle. The experiment was conducted at 10 sites across the Western North Atlantic (spanning 20 degrees of latitude) with natural variation in environmental drivers. In addition, we applied fertilization treatments to test the effect of experimental nutrient addition on seagrass recovery rates (N = 5). During one year post-disturbance, we measured the recovery of T. testudinum shoots as well as several environmental drivers (temperature, light, nutrient availability, fish and turtle grazing pressure), and after one year we quantified the recovery of the number of shoots and the amount of above- and below ground biomass within the disturbed patch. We used a generalised mixed model approach to assess what factors are driving above- and below ground recovery rates.