The ecology of ponds is threatened by urbanisation and as cities expand pond habitats are disappearing at an alarming rate. Pond communities are structured by local (water quality, physical) and regional (land-use, connectivity) processes. Since ca1904 >80% of ponds in Birmingham, U.K., have been lost due to land-use intensification, resulting in an increasingly diffuse network. A survey of thirty urban ponds revealed high spatial and temporal variability in water quality, which frequently failed environmental standards. Most were eutrophic, although macrophyte-rich, well connected ponds supported macroinvertebrate assemblages of high conservation value. Statistically, local physical variables (e.g. shading) explained more variation, both in water quality and macroinvertebrate community composition than regional factors. Nonetheless, habitat availability within the wider landscape was important. Ecosystem functioning (leaf-litter breakdown) along a rural-urban gradient was confounded by habitat area, despite a decrease in functional redundancy. Ponds are identified that promote network connectivity and management of land-use within 100m may buffer against diffuse pollution with reductions in riparian shading required to improve growth conditions for oxygenating vegetation and to reduce nutrient levels. The results indicate that many urban ponds are threatened habitats that require active management to protect and restore water quality, biodiversity and ecosystem functioning.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:575599 |
| Date | January 2013 |
| Creators | Thornhill, Ian |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/4275/ |
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