Figure 3
Explaining the emergence of modularity. (a) For a certain random landscape (the one shown in Fig. 1), average node densities as a function of the distance to a focal node (equivalent to threshold distance in Fig. 2). Each solid line represents the density of nodes (nodes/Km2) around a specific node in the landscape. Black dots represent the average density experience across all nodes. The thick black line highlights a particular node, one can see how the density can be lower or larger than the landscape average as a function of the distance to that focal node. Only for very large distances, the density converges to the average. To calculate node density, the area considered around the focal node was only the area that fell within the latitude and longitude limits of the landscape. Variance in node density is higher, the closer we look around a specific point in the landscape. (b) The modularity of the spatial network can be explained by the standard deviation of the node density around the nodes in the landscape. This panel shows a hundred different landscapes (each with 100 habitat fragments), where each line represents a different random landscape.
