Temporary tracks, persistent impacts? An evaluation of short-term usage peatland tracks.

Peatlands are a globally important wetland habitat, estimated to contain over a third of terrestrial soil carbon, placing their preservation and restoration at the forefront in debates around climate change mitigation. Anthropogenic activities, however, are driving peatland degradation loss both directly and indirectly. One such activity, is the creation of linear disturbances such as roads and tracks. The expansion of these networks, frequently in pursuit of resources, or the desire to explore remote regions, is rapidly outpacing research, with long time lags often experienced before impacts are appreciable.

In 2013 an experiment was established at Moor House, an upland blanket peatland in northern England to examine the impacts of temporary plastic mesh tracks on peatland functioning. A 1.5 km long plastic mesh track was installed and split into five different treatments based on frequency of usage. The tracks were abandoned in 2015/16, and no further vehicular usage occurred. In 2020, 18 7m long sections of this track were removed, to intensively examine the ecohydrological effects of removal compared to leaving the track to overgrow. The impacts of different treatments were evaluated on the ecohydrology; removed vs abandoned track, previous usage frequency, delayed usage, and unsurfaced track. Detailed surficial structural (nanotope) assessments of the tracks were carried out, to compare ruts, centres and controls. Additionally, soil moisture measurements, overland flow sediment, peat cavity strength measurement, hydraulic conductivity, bare peat occurrence and vegetation diversity were recorded.

Across all treatments alteration of the surface nanotopography was observed, loss of vegetation diversity after track removal and a reduction in vegetation height across all treatments occurred compared to controls, both on the track and along track edges. Our nanotope surveys augmented vegetation recovery assessments, demonstrating how different conclusions can be drawn, depending on whether vegetation-only or more complete assessments of surface condition are undertaken. Peat cavity strength on the tracks, measured using a peat specific penetrometer, suggests the persistence of vehicular compaction in the post abandonment and track removal periods. We also present data from overland flow sediment traps, hydraulic conductivity, and soil moisture surveys. Our findings suggest that where mesh track is to be removed, then additional revegetation interventions are required. We demonstrate that because the impacts of tracks, including mesh tracks, even after only light, short duration use, are long-lived, careful consideration of the necessity of tracks is required prior to their construction on peatland.