Source/sink patterns of disturbance and cross-scale mismatches in a panarchy of social-ecological landscapes
Land-use change is one of the major factors affecting global environmental change and represents a primary human effect on natural systems. Taking into account the scales and patterns of human land uses as source/sink disturbance systems, we describe a framework to characterize and interpret the spatial patterns of disturbances along a continuum of scales in a panarchy of nested jurisdictional social ecological landscapes (SELs) like region, provinces, and counties. We detect and quantify those scales through the patterns of disturbance relative to land use/land cover exhibited on satellite imagery over a 4- yr period in the Apulia region, South Italy. By using moving windows to measure composition (amount) and spatial configuration (contagion) of disturbance, we identify multiscale disturbance source/sink trajectories in the pattern metric space defined by composition and configuration of disturbance. We group disturbance trajectories along a continuum of scales for each location (pixel) according to broad land-use classes for each SEL level in the panarchy to identify spatial scales and geographical regions where disturbance is more or less concentrated in space indicating disturbance sources, sinks, and mismatches. We also group locations by clustering, and results are compared in the same pattern space and interpreted with respect to disturbance trajectories derived from random, multifractal and hierarchical neutral models. We show that in the real geographical world spatial mismatches of disturbances can occur at particular scale ranges,because of cross scale disparities in land uses for the amount and contagion of disturbance, leading to more or less exacerbation of contrasting source/sink systems along certain scale domains. All cross-scale source/sink issues can produce both negative and positive effects on the scales above and below their levels, i.e., cross-scale effects. Through the framework outlined in our examples, managers, as well as stakeholders belonging to SELs in the panarchy, can be aware of specific scale ranges of disturbance where mismatches might occur and that will help them to value where and how to intervene in the panarchy of SELs to enhance the benefits and to minimize negative effects.