Response of blanket bog vegetation to drain‐blocking

Abstract

Question: Does blocking of moorland drains increase bog vegetation on blanket peat? Location: Two sites with blocked drains and two with unblocked drains on Forsinard Flows National Nature Reserve, Sutherland, UK. Methods: Vegetation cover was recorded from 70 locations, with 12 sampling points at different distances (0.5‐14.5 m) from moorland drains in each location. Gradients in the cover of species indicative of wet and dry conditions, as well as bog recovery and degradation in relation to distance from drain, were compared from a sample of drains at two sites with blocked drains and two with unblocked drains. Results: There was evidence for drain‐blocking having a negative effect on vegetation indicative of drier conditions and bog degradation. One of the blocked sites had the lowest values of these indices near to the drain and increasing at greater distances perpendicular from the drain. The two unblocked sites, and the other blocked site, had a contrasting pattern of highest values of these indices close to the drain declining with distance. Cover of species indicative of bog recovery was greater where the drains had been blocked for the longest time. Conclusions: In some cases drain‐blocking can improve the ecological functioning of blanket bogs by increasing cover of healthy bog vegetation. Further studies into the causes of such variability in restoring vegetation through drain‐blocking are needed to aid targeting of peatland restoration projects to areas or methods most likely to be effective.

An experimental study on the response of blanket bog vegetation and water tables to ditch blocking

“…Unlike the ditches investigated by Stewart and Lance (1991), the ditches studied by Bellamy et al (2012) mostly ran downslope. Vegetation composition and cover were measured in transects perpendicular to the long-axes of the ditches.…”

“…On a blanket peatland in NE Scotland, Bellamy et al (2012) looked at drainage and re-wetting effects on vegetation composition using two sites where ditches had been blocked and two where the ditches remained open. Unlike the ditches investigated by Stewart and Lance (1991), the ditches studied by Bellamy et al (2012) mostly ran downslope.…”

Restoration of blanket peatlands

“…Vegetation composition surrounding unblocked drains and drains which had been blocked for between five and eleven years was surveyed. Bellamy et al (2012) found only drains blocked for the greatest period of time, in one of the two studied catchments, had vegetation compositions indicative of a recovering peatland. Vegetation recovery following blocking may lag hydrological response, consequently these slow response times may reflect this.…”

“…Nonetheless, only Bellamy et al (2012) have considered vegetation response to peatland drain blocking. Vegetation composition surrounding unblocked drains and drains which had been blocked for between five and eleven years was surveyed.…”

“…Although this activity may cause stabilisation of the peat surface, the resulting community of species will not be typical of a blanket peatland. If the intention of restoration is to preserve blanket peatland ecology and encourage peat accumulation it is important to ensure that blanket peatland communities, which are adapted to low nutrient availability (Bellamy et al, 2012), are able to re-establish following intervention. At present it is not known how blanket peatland ecology will respond to lime, seed and fertilisation in the long term and further research is required in order to understand the impact of stabilisation practices on blanket peatland terrestrial ecology.…”