The effect of landscape-scale environmental drivers on the vegetation composition of British woodlands

Assessment of factors influencing woodland vegetation composition across Britain was made using multivariate techniques to analyse data gathered during the 1971 National Woodland Survey. Indirect gradient analysis (unconstrained ordination using detrended correspondence analysis) suggested a gradient strongly associated with nutrient availability and pH. Direct gradient analysis (constrained ordination using canonical correspondence analysis) and variation partitioning were used with over 250 ecophysiologically relevant variables, including climatic, geographical, soil and herbivore data, to model the response of woodland vegetation. Although there was a high degree of multicollinearity between environmental variables, analysis revealed the vegetation composition of surveyed woodlands to be primarily structured by geographical, climatic and soil gradients, in particular rainfall, soil pH and accumulated temperature. The woods have recently been resurveyed. The results of this analysis therefore provide a baseline against which species dynamics can be assessed under a series of conservation threats, such as land use and climate change