What causes the vulnerability of endemic animals? A case study from Sri Lanka

Abstract

Around the world, endemic species with restricted ranges seem to be at particular risk of extinction. When range size is controlled, lowland continental species may be especially at risk, more so than island or montane species. Our study aimed to investigate reasons behind the high vulnerability of endemic species. In Sri Lanka, largescale national surveys and intensive localized fieldwork established that endemic plant and animal species are mostly associated with undisturbed rainforest habitats. On the other hand, non-endemic species used both forest and non-forest habitats almost equally, suggesting they are less likely to suffer from deleterious edge effects. To understand the different distribution of endemic and non-endemic species, our study focused on rats. Compared to the widespread species, the endemic rat species had a larger home range and fed on fewer species of forest fruit, possibly indicating greater specialization. The abundance of the endemic species was also negatively correlated with the abundance of the non-endemic species, to which it was behaviourally subordinate. Greater specialization and competitive inferiority could both contribute to the vulnerability of endemic species.

Mammal and bird species held in zoos are less endemic and less threatened than their close relatives not held in zoos

“…While it is unclear what role the geographical barriers that promote high incidences of endemism, such as those inherent in oceanic island and montane ecosystems, have as obstructions to collectors (both for zoos and for the pet trade), our results may suggest that the simple inaccessibility of small islands, high‐altitude forests and other remote ecosystems may be predictors of species representation in zoos. Montane and island endemics are also often specialized to narrow ecological niches (Wijesinghe & Brooke, ; La Sorte & Jetz, ) and recreating their specialist requirements in captivity may prove challenging. Indeed, it is possible that if a zoo faces a choice of obtaining a lowland or continental species with simple requirements and a good breeding record, or a closely related, superficially similar island or montane endemic that may be hard to obtain, difficult to keep, and with an unknown record of breeding success, the rational choice is to choose the former.…”

The link between international trade and the global distribution of invasive alien species

“…The absence of endemism in models, excluding Australia and New Zealand (but including 224 other countries), is somewhat surprising, as one could posit that the greater specialization and/or reduced competitive ability of endemic species (Lavergne et al 2004;Wijesinsinghe and Brooke 2004) would make regions with high endemism more vulnerable to invasions. Fig.…”

The effectiveness of a Mesoamerican ‘paper park’ in conserving cloud forest avifauna

“…However, the buffer zone points sampled within the present study were well within the recognized altitudinal ranges for most of these range-restricted species (Howell and Webb 2005;Stiles et al 1990), and a highly significant turnover of range-restricted to generalist species occurred between buffer and boundary zone points both located between 1,300 and 1,500 m. This therefore implies that differences in the proportions of rangerestricted species are again in likelihood due to different levels of anthropogenic disturbance and associated park protection rather than altitude. Wijesinghe and Brooke (2004) explain that this could be because range-restricted species tend to be highly specialized, adapted to narrow habitat and dietary requirements due to the unique conditions created by their localized environment. Therefore they are unable to persist in buffer zone environments where edge effects significantly alter environmental characteristics.…”