Figure 1
Levels of habitat loss and their differential consequences for habitat patches. Habitat sites (grey hexagons) and non-habitat sites (white hexagons) are distributed randomly on a hexagonal lattice. The shown levels of habitat loss q illustrate the five main phases of habitat degradation identified in this study (Table 1): the percentages indicated above the panels are mid-interval values characteristic of Phases 1–5. For example, q = 10% means that 10% of habitat cover is lost and that 90% of habitat cover remains, which is the mid-interval value characteristic of Phase 1 (Table 1). The upper two panels show connected landscapes (Phases 1–2, where the level of habitat loss is below the percolation threshold, q < qc), while the lower three panels show fragmented landscapes (Phases 3–5, where q > qc). The pictures illustrate relatively small lattices (20 × 20 sites). In contrast, all numerical investigations in this study were carried out on larger lattices (100 × 100 sites), and a landscape’s property of being connected or fragmented is defined in the theoretical limit of infinite lattice size.
