Assessing the representativeness of nature reserves using multivariate analysis: Vascular plants and breeding birds in deciduous forests, western Norway

Abstract

Multivariate analyses were used as a tool for delimiting representative types of 60 deciduous woods in western Norway based on vascular plants and breeding birds. The relationships between the species assemblages and 47 environmental and other explanatory variables were investigated. Environmental variables considered included climate, area, habitat features, landscape attributes, and disturbances. Two-way-indicator-species-analysis was applied to the data and revealed four representative types of deciduous forests based on the plants, but only one representative type based on the bird data. Detrended correspondence analysis, canonical correspondence analysis, and canonical variates analysis suggested that the major gradients of floristic variation are primarily related to climatic variables such as July temperature and humidity, reflecting the strong west-east gradient in oceanicity in western Norway. One of the four representative plant groups is not represented in the existing reserve system, showing that additional reserves are needed to ensure a fully representative system. The differences between representativeness based on plants and birds are discussed.