A study of the affects of Habitat fragmentation on the woodland edge microclimate and on the structure and composition of woodland ground flora

Abstract

A study of the affects of habitat fragmentation on the microclimate and ground flora at the edge of an area of secondary woodland was conducted. Vegetation was sampled in an array of 60 quadrats arranged in transects running parallel with the edge of the woodland and at increasing distances from it. Species abundance at each quadrat was measured using the Domin scale. Point quadrats were used to allow assessment of vegetation structure and canopy cover at each quadrat was described using a point centred quarter method. Environmental variables including illumination, P.A.R., soil temperature, air temperature, soil moisture, soil organic content and pH were measured at each quadrat. Data was analysed using a variety of univariate and multivariate statistics. Results indicated a microclimatic and vegetational transition zone' of approximately 10 metres in diameter at the northern boundary of Moorhouse Wood and adjacent habitats. This was indicated by; 1. Illumination, P A R., soil and ah temperature, soil moisture and soil organic content all underwent significant alterations over this distance and continued to change more gradually further into the wood. 2. Edge oriented patterns of variation were found in both canopy and ground floral community composition and in general, species with ecological preferences for disturbed or for warm and light conditions were increased in abundance at the edge of the woodland. Some evidence of invasion by non-woodland species was found but these did not appear to be colonising the woodland interior. 3. Ground vegetation structure was altered by proximity to the woodland edge. This was shown to be unrelated to most microclimatic variables and it is suggested that a high level of disturbance is more likely to be responsible for the decreased height of vegetation at the boundary. Comments are made concerning the significance of these findings and their importance in understanding the affects of habitat fragmentation on the woodland microclimate and ground flora.