Direct and indirect influences of landscape structure on local habitat quality

Understanding the influence of surrounding landscape structure on local habitat quality is necessary to complement the modelling of empirical relationships between habitat quality and species distribution patterns. Traditional models explain patterns of bi odiversity as a function of 'habitat amount in the landscape', irrespective of spatially - explicit variation in habitat fragmentation or habitat quality, implicitly ignoring the interdependence between spatial components of land - use change. The contrasting hypothesis - that local habitat units are not interchangeable because their habitat attributes are dependent on variation in surrounding habitat structure at both patch and landscape levels - was tested using a hierarchical causal modelling approach . S uch models are observation - intensive, so we generated fine - grained measures of habitat patch internal heterogeneities (proxies for habitat quality) from very high resolution Earth Observation images over multiple spatial extents. The results demonstrate the ca usal dependence of local habitat quality on surrounding patch and landscape context, and indicate that the influence of landscape pattern on habitat structure can be mediated by the cross - level dependencies between landscape and patch attributes. From the spatial context dependence of habitat quality, we conclude that a substantial degree of interdependence among habitat effects is likely to be the norm in determining the ecological consequences of habitat fragmentation.