Modifying connectivity to promote state change reversal: the importance of geomorphic context and plant–soil feedbacks

Authors: Peters, Debra; OKIN, GREGORY - University Of California (UCLA); Herrick, Jeffrey - Jeff; Savoy, Heather; ANDERSON, JOHN - New Mexico State University; SCROGGS, STACEY - New Mexico State University; ZHANGE, JUNZHE - University Of California (UCLA)

Submitted to: Ecology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/16/2020
Publication Date: 4/16/2020
Citation: Peters, D.C., Okin, G., Herrick, J.E., Savoy, H.M., Anderson, J., Scroggs, S.L., Zhange, J. 2020. Modifying connectivity to promote state change reversal: the importance of geomorphic context and plant–soil feedbacks. Ecology Letters. 101(9):e03069. https://doi.org/10.1002/ecy.3069.
DOI: https://doi.org/10.1002/ecy.3069

Interpretive Summary: In drylands, state changes maintained by positive feedbacks are difficult, if not impossible, to reverse. We imposed an experimental treatment by manipulating connectivity of horizontal redistribution of resources by wind or water on different geomorphic surfaces to alter these feedbacks between plants and soils. The goal was to shift woody plant- dominated systems back towards perennial grasses and reverse the effects of desertification. Our results show that Connectivity Modifiers (ConMods) are most effective on sandy soils where wind is the dominate vector. Grass recovery occurred within 6 years after plant-soil feedbacks developed to overwhelm effects of precipitation. Gravelly soils on stable surfaces with low sediment movement by water had the least potential for grass recovery. This approach has application to drylands globally where desertified lands have suffered losses in ecosystem services, and to other ecosystems where connectivity-mediated feedbacks modified at fine-scales can be expected to impact plant recovery and state change reversals at larger scales.

Technical Abstract: State changes maintained by positive feedbacks are notoriously difficult, if not impossible, to reverse. An experimental treatment was imposed by manipulating connectivity of horizontal redistribution of resources by wind or water on different geomorphic surfaces to alter plant-soil feedbacks. The goal was to shift woody plant- dominated systems back towards perennial grasses to reverse the effects of desertification. Results show that Connectivity Modifiers (ConMods) are most effective on sandy soils where wind is the dominate vector, resulting in grass recovery within 6 years after plant-soil feedbacks developed to overwhelm effects of precipitation. Gravelly soils on stable surfaces with low sediment movement by water had the least potential for grass recovery. This approach has application to drylands globally where desertified lands have suffered losses in ecosystem services, and to other ecosystems where connectivity-mediated feedbacks modified at fine-scales can be expected to impact plant recovery and state change reversals at larger scales.