Patterns of organisation in changing landscapes: implications for the management of biodiversity

Despite the widespread need to predict and assess the effects of landscape change on biodiversity, the array of tools available for this purpose is still limited. Species' patterns and human activities such as land use respond to the environment on their own suite of scales in space and time so that their interactions are overlapping but complex. It is difficult, therefore, to relate biodiversity to patterns described solely by metric assessments of spatial heterogeneity. In this methodological paper, we therefore propose consideration of two measures of landscape organisation which focus on the relationships between different properties of the landscape system ( e. g., soil type distribution, land use distribution), rather than on their description alone. Alpha organisation measures the degree to which the distribution of features such as land use deviate from a random distribution, measured here as fractal dimension from the semivariogram of a variable describing agricultural intensity. Beta organisation measures the degree of deviation by which the spatial distribution of one property ( e. g., human land use) is independent of the distribution of another (e.g., soil type) and was derived from relative mutual information (= redundancy) between the 'agricultural land use' and 'soil types'. These measures are illustrated in a rural landscape of the lower Seine valley, at two scales of observation, and at two dates ( 1963 and 1999) separated by substantial agricultural change due the European Common Agricultural Policy (= CAP). The results show that analysis of patterns of agricultural activity across a range of spatial scales (alpha organisation), or across the pattern of spatial variation in soil types (beta organisation) reveal how the agricultural actors respond to environmental constraints at different scales. This organisation concept relates to the metastability of landscape systems, and suggest possible correlation between high values of landscape organisation and high levels in biodiversity.