Decoupled recovery of ecological communities after reclamation

Authors: SYLVAIN, ZACHARY; Branson, David - Dave; Rand, Tatyana; West, Natalie; ESPELAND, ERIN

Submitted to: PeerJ
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2019
Publication Date: 6/21/2019
Citation: Sylvain, Z.A., Branson, D.H., Rand, T.A., West, N.M., Espeland, E.K. 2019. Decoupled recovery of ecological communities after reclamation. PeerJ. https://doi.org/10.7717/peerj.7038.
DOI: https://doi.org/10.7717/peerj.7038

Interpretive Summary: Restoration is an important component of sustainable land management and helps recover ecosystem productivity and services necessary to support wildlife, livestock and human well-being. In the US Great Plains, development for oil and gas extraction is a common driver of land-use change. Most studies assessing how successfully restoration practices recover degraded ecosystems and their function focus only on the recovery of plants, however many groups of organisms interact to promote ecosystem functions, of which plant communities alone provide only a subset. We sampled plants, soil properties (such as pH, organic matter content and salinity) and soil nematodes (small worm-like animals that contribute to plant growth and development) on reclaimed well sites in western North Dakota, and on undeveloped rangeland at two distances (50 m and 150 m) from the edges of each reclaimed well site. We found that current restoration practices in this system successfully recovered nematode community function on reclaimed well sites relative to undeveloped rangeland, but soil conditions and plant communities were not successfully recovered. Soils on reclaimed well sites had higher pH and greater salt concentrations and plant communities on these sites were composed of fewer native plant species and more weedy and invasive plants relative to those on undeveloped rangeland. Our results emphasize the importance of seeding native plants as part of restoration efforts and that high salt concentrations in reclamation soils may impede native plant recolonization and ecosystem recovery.

Technical Abstract: 1. Restoration of degraded landscapes is often required to regain ecosystem function, which is predicated on multiple biotic and abiotic interactions. Nevertheless, the discipline of grassland restoration is almost entirely focused on plant community data that only reflect a small subset of ecosystem functions. 2. We carried out a multi-trophic study to assess community recovery following energy development in the northern Great Plains of the US. We compared soil abiotic factors, plant species composition and cover, and nematode trophic structuring on reclaimed well sites comprising a chronosequence of 2 – 33 years since restoration with those at two distances (50 m and 150 m) from reclamation edges on adjacent, intact prairie. 3. Soil abiotic conditions and plant communities in restorations did not match conditions on adjacent, intact prairie even after 33 years. Soils in restorations had higher concentrations of salts and higher pH than intact soils. Restorations had lower overall plant cover, a greater proportion of exotic and ruderal plant cover and lower native plant species richness than intact rangeland. 4. However, nematode communities appear to have recovered successfully following restoration. We observed nematode functional group abundance differences between reclaimed well sites and intact prairie, but community composition and structure did not differ. 5. Synthesis and applications. Current restoration practices in this system recover the functional composition of nematode communities but not soil abiotic conditions or plant communities. Our results emphasize the importance of assisting colonization of native plant species, and that high salinity soil conditions at reclamation sites may create a persistent impediment to native plant growth and ecosystem recovery. Soil chemistry may be altered and toxicity should be mitigated in reclamations where substantial soil disturbance has occurred.