AbstractThe land use history of a South Wales dune system, Merthyr Mawr Warren is described with reference to the present recreational use.
Periodic trampling and wear by motor cycle was applied to previously undamaged vegetation and the effect monitored quantitatively over three seasons. Vegetation is shown by multivariate analysis to be related first to slope and aspect and then to the treatment applied. On south facing slopes a predominately herbaceous community shows some resistance to light trampling but is damaged with increasing intensity. Different modes and speeds of recovery occur when the community is released from trampling stress. North aspects are dominated by graminaceous species which increase in abundance in response to trampling. There is some evidence that the relative abundance of Festuca rubra and Poa pratensis approaches that in the surrounding untreated vegetation in the third year. Some strategies for species survival are considered.
Periodic trampling and mowing were applied over two seasons to dune grassland both exposed to rabbit grazing and within an exclosure. An interactive plot design allowed the contemporaneous examination of nutrient addition to these treatments. Multivariate analysis indicated that grazing and trampling each produced distinct changes in species composition. The balance of a competitive interaction between the major grass species is influenced by either trampling which favours Poa pratensis or grazing to which Festuca rubra is better adapted. Treatment interactions are qualified by Analysis of Variance. A short trampled sward attracted rabbits. The consequences for nutrient cycling of selective defoliation and excretion by rabbits are discussed.
Rabbit use of the plots was determined by faecal pellet counts and direct observation. Vandalism hindered determinations of faecal pellet degradation rate.
The use of inexperienced recorders for large data volume, long term monitoring is considered.
|Date of Award||Jun 1987|