Using biogeochemical insights to restore drylands now and into the future

Kristina E. Young, Catherine Cort and Anthony Darrouzet-Nardi, Biological Sciences, University of Texas at El Paso, El Paso, TX, Sasha Reed and Daniel E. Winkler, Southwest Biological Science Center, U.S. Geological Survey, Moab, UT, Scott Ferrenberg, Department of Biology, New Mexico State University, Las Cruces, NM, Akasha Faist, Department of Animal and Range Sciences, New Mexico State University, Las Cruces, NM

Background/Question/Methods
Dryland degradation is an accelerating global problem. Many of the processes involved in degradation are biogeochemical in nature, involving changes to the distribution and accumulation of resource pools and fluxes. These biogeochemical changes can make it difficult to restore productivity and services to degraded regions, especially when changes are accelerated by climate change. While water limitation has received the most attention in explaining limited recovery in drylands, other resources, such as nutrients, are recognized drivers of productivity. Investigations into multiple resource limitations and asynchrony in resource availability in drylands is providing more nuanced understandings of the drivers behind ecosystem functions. These biogeochemical insights may be useful in predicting restoration outcomes and aiding restoration goals, which often seek to increase primary production and ecosystem services such as soil stability and water retention. However, a greater understanding of the biogeochemical process at work in drylands, and how they will respond to climate change, is necessary. To fill this gap, we examined restoration literature that addresses biogeochemistry in degraded drylands and examined dryland biogeochemical research in a restoration context to synthesize findings, identify research gaps, and suggest future directions.
Results/Conclusions
Our synthesis of the restoration and biogeochemical literature identified multiple ways biogeochemical understandings augment dryland restoration outcomes, including: (1) timing restoration around resource cycling and uptake, (2) connecting heterogeneous landscapes, (3) manipulating resource pools, and (4) using organismal functional traits to a restoration advantage. Important research gaps emerged in our synthesis. While most empirical research focused on manipulating resource pools and organismal traits, fewer experiments examined pre-existing and manipulable temporal and spatial components into research questions, such as the seasonality of restoration or using naturally occurring pockets of high-resources to begin restoration action both now and under future climate change. There is a need for more experiments addressing these questions, since the limited data suggests planning around areas and times of increased resource and soil moisture availability may be a determining factor in dryland restoration outcomes. Further questions centered on understanding multiple resource limitations over space and across time and understanding how climate change will impact each of these processes is necessary for managing and restoring this highly vulnerable biome.