Abstract"Disused railway lines make excellent vehicles to study ecological processes being linear, of fixed width, constructed in the same way, with potential vegetation influences such as time since abandonment and climate being easy to discover. Moreover they are rarely studied. Thus the current study fills a gap in the literature.
Samples were taken from a total of 176 releves across 35 sites on 22 different railway lines within England and Wales. The communities were analysed using the standard UK phytosociological method, the National Vegetation Classification (NVC). Few similarities were found with published NVC communities. A large number of communities had affinities with MG1 Arrhenatherum elatius grassland but with un-described sub-communities, with ruderal species or wood and scrub species as major components. Similarly, a number of communities had affinities to OV communities but with different constant species. Hence it is difficult to apply the NVC to synanthropic habitats and that there are ruderal communities in existence that are not described in the NVC.
A modified Braun-Blanquet approach to analysing the vegetation data was also undertaken. Hierarchical analysis identified seven clusters equating to communities. Species characteristic of each community were identified using Indicator Values, although these species rarely had both high fidelity and exclusivity.
The potential contribution of environmental, temporal and edaphic variables to the development of these communities was assessed. This was underpinned by the theoretical question of succession. Is it an ordered progression through to a climax community or is the process much more stochastic ?
There is no simple relationship between time since abandonment and any measure of successional progress. However CCA analysis showed that some factors, primarily abiotic, were significantly associated with community composition. Time since abandonment only becomes significant when it is combined with soil factors. This suggests that vegetation composition is not entirely random in these communities.
|Date of Award||4 Aug 2016|
|Supervisor||PAUL ASHTON (Director of Studies) & MICHAEL POWELL (Supervisor)|
- ecological processes
- vegetation composition
- UK phytosociological method
- National Vegetation Classification
The Plant Communities of Disused Railway Ballast in Great Britain
HACKING, R. (Author). 4 Aug 2016
Student thesis: Doctoral Thesis