The Biodiversity and Metabolism of Peatland Pools

Knowledge of the ecology and ecosystem functioning of pools created by the peatland restoration method of drain-blocking is limited. This thesis provides the most comprehensive study of these peatland pool ecosystems to date. Data were collected to investigate the spatial and temporal distribution of macroinvertebrate communities in both drain-blocked and naturally-occurring pools on areas of blanket bog in northern England. Corresponding environmental data were analysed to identify any mechanisms underpinning biodiversity metrics. The metabolism (i.e. rates of photosynthesis and respiration) of drain-blocked pools was estimated using the diel dissolved oxygen (DO) method.

Drain-blocked pools were found to house macroinvertebrate communities similar to those in natural pools, including taxa characteristic of acid-mire pool habitats, thus providing suitable habitat for peatland aquatic taxa. There was some evidence that pools in reprofiled drains were more biodiverse than L-shaped pools. New pools were colonised quickly with taxon richness peaking in pools aged five to eight years, and pools aged 15 years housing some fauna not found in younger pools. Results suggested that gamma diversity would be best encouraged by creating a range of pool sizes with diverse vegetation composition.

Drain-blocked pools were found to be strongly heterotrophic, with high rates of respiration driven by elevated levels of dissolved organic carbon and the relatively large sediment-water interface. Water temperature and DO profiles obtained from pools in England, Scotland and Sweden revealed severe diurnal stratification regimes, with implications for sampling methodologies, gas fluxes and carbon cycling. This research will help to inform future drain-blocking schemes and also has relevance for studies analysing the biogeochemistry and biota of other shallow waterbodies.