Plant communities are a complex web of interactions which may harbor inherent resilience to global climate change. Assessment of plant assemblages to spatial and temporal variation can provide pertinent information of the adaptive capacity of species within plant communities. Although interspecific facilitation has been shown to be a main driver of plant community assemblages between populations, this study is unique in that it investigates facilitation as playing an integral role in within population variability. We examined how the direction and strength of spatial association to nurse shrubs varies between 10 Brachypodium populations along an aridity gradient in southeastern Spain. We also assessed within population phenotypic and fitness characteristics to microclimate variability driven by nurse shrubs in these habitats.
Results/Conclusions
Preliminary results indicate that aridity does predict spatial association between nurse shrubs and Brachypodium density between the two most extreme sites (xeric, mesic) but in an unexpected direction. In addition, in a subset of the data, we see a trend towards significant differences in morphological and fitness characteristics (stem height, spikelet length, number of seeds) between the plants found outside of nurse shrubs and those found underneath nurse shrubs at our most xeric site: ongoing genotyping indicates either spatial microclimate sorting or very high plasticity within species. Our preliminary results indicate that facilitative interactions may not only be an important driver for local adaptation within populations but may also play an important role in plant community resilience in semi-arid landscapes.