Correlates of extinction risk of birds from two Indonesian islands

Abstract

Size of distributional range, position in the range, body size and diet are some of the ecological traits that may correlate with local abundance. Evolutionary phenomena such as taxon cycles, acting over much greater time periods, may also influence abundance and promote species extinction. This paper assesses which of a wide range of ecological and historic traits best predict the variation in abundance of tropical forest birds on Sumba and Buru islands in Wallacea (Indonesia). In addition we seek to determine which traits predict species' ability to adapt t o secondary or logged forest. The most important correlates of both abundance and ability to transfer were those related to the evolutionary history of the species within the Wallacean Archipelago and not the traits that were more directly related to species ecology. These relationships are maintained when allowance is made for phylogenetic relationships. Our interpretation of the results is that recent colonists to an island are initially rare in the indigenous forest habitat but concomitant with an adaptation to local conditions they gradually become more abundant and taxonomically distinct from other populations of the same species. These results apparently contradict the taxon cycle hypothesis but this may be a result of our focus on indigenous forest habitats rather than on a wider range dominated by anthropogenic ones.

Range-Restricted, Specialist Bornean Butterflies Are Less Likely to Recover From Enso-Induced Disturbance

“…Another intriguing possibility is that widely distributed species might be inherently ''more adaptable'' and better able to exploit a wider range of ecological niches, as has been suggested for birds (Jones et al 2001) and primates (Harcourt et al 2002). Perhaps growth form generalists are less constrained (e.g., more plastic) on axes such as developmental time or temperature tolerance.…”

The relationship between population density, habitat position and habitat breadth within a neotropical forest bird community

“…Jones et al 2001), and this may be an additional problem, because although there may be high species richness in rainforest, many species are rare, meaning that they may have to be excluded in all but the most comprehensive studies. In fact, there have been very few macroecological studies undertaken on tropical forest taxa, presumably due to the lack of published databases on their ecologies or the difficulty of accumulating large datasets from the field.…”

“…Terborgh and Winter 1980), while large insectivorous birds may be particularly prone to decline following forest change (e.g. However, for island birds at least, increased level of endemism may be positively correlated with both local abundance and ability to tolerate forest change (Jones et al 2001). Since endemic taxa are, by definition, restricted geographically, they may be expected to be rare since local abundance tends to be positively correlated with range size (e.g.…”

Unusual abundance–range size relationship in an Afromontane bird community: the effect of geographical isolation?

“…Such adaptation is enabled by the restricted gene pool of the island population, whereas permanent gene flow prevents such a process on the mainland. On the other hand, widely distributed species that have recently colonized an island may have low abundances because they are exposed to an unknown environment already occupied by well adapted local species (Jones et al. , 2001).…”