The construction of pipelines to carry unconventional natural gas from wellhead to market represents a significant impact to terrestrial and aquatic ecosystems throughout much of the United States. Pipeline corridors present likely avenues for the spread of alien and invasive plant species into plant communities dominated by natives. To understand the vegetation on existing pipeline corridors, a detailed assessment was conducted within nine older (>20 year old) pipeline corridors in northeastern PA. Plants were identified and their percent covers estimated in 126 1m2quadrats during the summers of 2015 and 2016. Preliminary analysis revealed the presence of several distinct plant community types. This study seeks better characterize those communities, assess the degree to which they are comprised of native vs alien species, and whether they correlate with environmental parameters such as soils.
Results/Conclusions
A total of 144 vascular plant species was found in the 126 m2 of area analyzed, representing an unexpectedly high level of species richness. Shannon-Weiner indices for each pipeline segment ranged from 2.0 to 3.0, which were relatively low. Species-level analyses revealed that many of the plots were dominated by native meadow species like wrinkled goldenrod, swamp dewberry, and common cinquefoil. Other plots were represented by a community type dominated by Ericaceous subshrubs and native graminoids typical of acidic woods and meadows. Species in those communities included lowbush blueberry, sheep laurel, dwarf huckleberry, and Pennsylvania sedge. Local low spots with saturated soils were dominated by wetland species such as fringed sedge, soft rush and woolgrass. Soils proved to be acidic and relatively nutrient poor, except for two segments adjoining a golf course that had apparently received liming and fertilizer treatment. The mix of species in the plant communities encountered were different from those typically planted along pipeline rights of way. Thus, these communities develop from species that colonize the site and become established over time.