Figure 1.
Cumulative area plots of two Atlantic forest birds, the large-ranged black-fronted piping-guan (Pipile jacutinga) and the small-ranged orange-bellied antwren (Tenenura sicki — highlighted with a box).
Graph axes are the logarithm of cumulative area in patches up to a given size, versus the logarithm of that patch size. The lines are fitted linear regressions. A steep (more positive) slope, e.g. orange-bellied antwren, indicates that a range is composed mainly of relatively larger patches. Shallow slopes, e.g. black-fronted piping-guan, indicate birds with ranges composed of relatively many smaller forest fragments. Counter-intuitively, while the guan has a larger overall range and larger patches within that range, the shallower slope of its plot suggests that it is more fragmented (see text for further discussion).
Figure 2.
For 127 passerine birds of the Atlantic forest of Brazil, differences are evident between two measures of extinction risk: A) the area of a bird’s remaining range; B) metapopulation capacity, which accounts for range fragmentation as well as area.
Colors indicate IUCN Red List categories with red, orange, and green being the three ‘threatened’ categories. When accounting for the long-term extinction risk associated with fragmentation, a distinct group of 57 species with very low metapopulation capacity becomes apparent, of which 28 are deemed non-threatened by BirdLife.
Figure 3.
Slopegraphs (ref. [69]) comparing relative values of remaining range (left axis) and modified metapopulation capacity (right axis) for 2 subsets of bird species endemic to Brazil’s Atlantic forest.
Thick, center lines connect the value of remaining range to the value of metapopulation capacity for the same species. Thinner, gray lines on either side link to species labels, which are spread out for clarity. The colors of the center lines and the species’ label backgrounds reflect IUCN status (see key); only the names of species in the three threatened categories are colored. Clusters of species are highlighted, to indicate those of low range area, and high and low extinction risk due to fragmentation.