Challenges of scale when examining plant-interactions in arid ecosystems: micro, local, & regional [Wed. May 18]

In high stress environments, such as deserts, positive interactions among plants maintain biodiversity and productivity.  However, the role and mechanism of these positive interactions changes depending on the context of spatial scale.
I will discuss how positive plant-interactions in deserts change at the micro, local, and regional scale.  I also discuss the challenges associated with examining plant interactions at different spatial scales as a researcher, such as sampling techniques, community structure, and interacting factors.
Typically studies examining positive plant-interactions focus on local gradients, thereby neglecting micro or regional scales.  All spatial scales share similarities in that each have gradients that modifies the mechanism, magnitude, and direction of plant interactions.  Drawing parallels among different spatial scales and considering all three simultaneously as a response surface can provide a better understanding of positive interactions.  This can assist conservation biologist and restoration ecologists make better informed decisions when managing desert ecosystems in support of global biodiversity.

Alex Filazzola
PhD Student
York University
Toronto, Canada


Looking for hotspots while the world gets hotter: multi-species genetic data inform landscape-scale conservation in the face of climate change in the San Joaquin Desert of California.

Global climate change can create patterns of biodiversity where once-widespread species become restricted to small islands of persistence, commonly called climate refugia. Species can subsequently recolonize the intervening spaces between the islands, masking the historical range restriction. Advances in molecular genetic technology now allow us to see the signature of these historical restriction events. In our ongoing study of desert vertebrates in the San Joaquin Valley, we are layering patterns of population subdivision from multiple species into a composite map of historical population centers. We have significant population subdivison as well as pattern concordance among some species, suggesting past refuges in the Panoche Hills and the Carrizo Plain. A parallel study projecting the distribution of the blunt-nosed leopard lizard following the current climate change event shows both spots as potential refugia, suggesting the tantalizing possibility that contemporary hotspots may serve as future redoubts.


Michael Westphal
Bureau of Land Management
Hollister Field Office, CA