This study analyses vegetation succession following the clearance of Rhododendron in a sessile oakwood in North Wales. The Rhododendron has been cleared since 1984/5 and prior to clearance dominated the understorey. The succession was analysed in relation to the number of years since clearance; method of clearance; density of the former Rhododendron cover, and vegetation adjoining the site. An experiment was undertaken in the University's nursery to assess the presence and viability of seed within the seedbank, and the ability of the soil to support germination. Over 50% of the samples were dominated by bryophytes (60%), with birch, bramble and Rhododendron seedlings each present at less than 10%. There was a significant difference between the mean percentage crown cover of each TWINSPAN group; those groups with more light demanding species had a lower mean percentage crown cover than groups dominated by more shade tolerant species. Only bramble and birch germinated in soil collected from the two most recent years of clearance. Their presence is probably due to seed dispersed prior to clearance, and there is therefore no viable seed in the seedbank. Colonisation must therefore rely on immigration of seed. There was no significant difference between the ability of soil recently infested by Rhododendron, or the ability of peat, to support germination of Betula pendula or Festuca ovina. There is a significant difference between the frequency and abundance of vegetation and the year of clearance. With the exception of one plot, frequency and abundance increased with the number of years since clearance. Rhododendron seedlings are associated with a bryophyte cover. The site contains substantial Rhododendron coppice and seedlings, and continued eradication and containment programmes will be needed.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:665507 |
| Date | January 1989 |
| Creators | Hockley, T. G. |
| Publisher | Bangor University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://research.bangor.ac.uk/portal/en/theses/vegetation-succession-following-the-clearance-of-rhododendron-in-the-vale-of-ffestiniog(97ca4cf8-443e-4b13-abcf-5de9b42e8ca5).html |
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