Spatial and temporal dynamics of plants colonizing species-poor hedgerows
thesisposted on 15.12.2014, 10:33 authored by Janet I. Jackson
Hedgerows are increasingly being recognised as important in terms of landscape biodiversity. In Britain, recent hedgerows are not valued as highly as ancient hedgerows due to distinct differences in species-richness and historical significance. However, other potential ecological functions of species-poor hedgerows may have been overlooked, especially their potential role as corridors and habitats that help overcome the effects of habitat fragmentation. This thesis examines the spatial and temporal distributions of plant species in recent hedgerows in close proximity to remnant ancient woodland seed sources, and evaluates immigration, colonization and establishment processes that occur at this interface.;Transects were used to sample plant species distributions across the transition between remnant ancient woodland communities and adjoining Enclosure Act hedgerows in Northamptonshire. An analysis of the distribution of herbaceous plant species within the seed bank across the woodland-hedgerow transition is also presented. A census of colonizing woody plant species within the Experimental Hawthorn Hedgerows at Monks Wood, in Cambridgeshire was used to investigate the: i) influence of seed source availability, ii) immigration potential, iii) colonization and iv) establishment success under three hedgerow management regimes.;Woodland herbaceous plant species were found to have limited spatial and temporal dispersal strategies and species successfully dispersing into adjoining species-poor recent hedgerows were those able to reproduce vegetatively. The seed bank analysis showed that species of disturbed landscapes were dispersing into the woodlands, but were not successfully colonizing. Woody plant species dispersal was found to be operating at a larger spatial scale than herbaceous plant species. The abundance of seed sources and the availability of potential bird dispersers were found to correlate with the colonization success of woody plants within the Experimental Hedgerows, but the survival and establishment was related to hedgerow structure. The implications of these findings in relation to seed source-sink dynamics, corridor theory, habitat function, conservation and landscape planning were considered.