Restoring plant communities for ecosystem function and services is essential, yet challenging work post natural resource extraction. Shale oil and gas development, via the construction of infrastructure such as well pads and pipelines, removes not only plant communities but leaves highly disturbed soils as the foundation for restoration. Loss of topsoil and soil structure and compaction can impede the re-establishment of native plant communities, and facilitates the spread of invasive plants. Furthermore, current reclamation regulations largely constrain restoration to erosion and sedimentation control with fast-growing exotic grasses, rather than promote the establishment of diverse, native plant communities. To investigate potential opportunities based on these constraints we; 1) constructed mock well pads with various decompaction treatments and native seed mixtures, 2) conducted plant community surveys across environmental gradients on a gas pipeline seeded with native plants, and 3) performed a discourse analysis on reclamation literature, including state and federal regulations, grey literature, and peer-reviewed journals. We used ANOVAs to assess seed mix establishment by soil treatment on the mock well pads, and structural equation models (SEM) to determine direct (invasive plant cover) and indirect (soil pH) factors of native mix cover on the pipeline eight years post reclamation.
Results/Conclusions
Shoot and root biomass of native warm season grasses were not significantly impeded by soil compaction (p = 0.05) on mock well pads. On the pipeline, native plants from the original seed mix were the dominant component of the current plant community on the 76 survey sites. Native plants with wide ranging tolerance to soil conditions, such as Dichanthelium clandestinum, Panicum virgatum, and Chamaecrista fasciculata, were persistent across the pipeline. Survey sites where populations of the invasive annual Microstegium vimineum had a rapid spread rate between 2009 and 2013 persisted with high densities in 2016 (p = 0.004). The SEM provided evidence that low soil pH predicted this high spread rate, and was an indirect driver of low mix establishment. Our research supports a growing body of evidence that native plant restoration on highly disturbed lands is possible, yet transmission to practice and restoration at scale is limited. As with the mined land discourse, the shale oil and gas reclamation discourse across Appalachia lacks terminology in ecological interactions. For a shift in reclamation regulations and practices, and the ability for stakeholders to prioritize a broad suite of ecosystem services, there must be a fundamental change in the reclamation discourse.