Bat Species Found Only on Islands in Trouble Worldwide

About a quarter of the over 1,300 species of bat are endemic to islands, meaning they are found there and nowhere else. These island-restricted bats play important roles in island ecosystems through seed dispersal, pollination, and pest control. On some islands, bats are the only indigenous mammals (the ability to fly helped them make it to places that other mammals never reached).

However, a knowledge gap exists and little is known about the ecology and conservation status of many island-restricted bats. A recent study out of the University of Helsinki investigated these gaps with the hopes of guiding future research efforts and conservation priorities.

Islands, due to their isolation, pose peculiar challenges to the animals that live there. This often leads to the evolution of unique species found nowhere else on Earth. Islands can also serve as reservoirs for species gone extinct elsewhere, as is the case for the New Zealand lesser short-tailed bat (Mystacina tuberculata). This sole surviving member of the family Mystacinidae lives only on New Zealand.

Islands are also some of the most vulnerable habitats in the world.

“In general, island ecosystems are less complex than mainland ones, as they can support only a small number of species due to the limited amount of resources,” says Irene Conenna, the study’s main author.

“Consequently, island ecosystems are less resilient to disturbances. They are especially vulnerable because they are threatened by the combined effects of natural disturbances, typical of island ecosystems, and human-generated disturbances.”

Island-restricted bats face human threats such as habitat loss, harvesting for human consumption, climate change, and invasive species. Knowledge of their ecology and conservation status is essential to saving them before it’s too late.

To this end, Conenna and her colleagues investigated which island-restricted bat species and islands worldwide lag behind in scientific attention. They collected data on the bats’ distribution and conservation status and tallied the number of research papers dedicated to each species.

The researchers found that island-restricted bats are significantly more threatened than other bat species. Yet, scientific knowledge of these bats is scarce; there were one or no research articles for about four out of ten island-restricted bat species. Additionally, geographic areas rich in island-restricted bats, such as Southeast Asian and Oceanic islands, remain largely unexplored. This means there might not be enough information available to determine conservation status, and subsequent action plans, for many island-restricted bats.

Conenna and her co-authors suggest that future funding for bat research should target priority islands and species identified by their analysis, which includes regions and species that are still poorly known and face many significant threats.

“It is of foremost importance to complete risk of extinction assessments of the least known species, as these are likely to face strong declines before interventions can be put in place,” says Conenna.

“This was the case for the Christmas Island pipistrelle, which, despite intensive survey efforts, has not been recorded since 2009 and is likely extinct.”

Directing funding and research effort towards the priority islands and species identified in this study would help the development of successful and cost-efficient conservation plans. More data on these bats will provide a more accurate picture of their extinction risk, which in turn will lead to conservation priorities based on actual data. And hopefully, the end result will be stopping the decline of island-restricted bats.

Reference:

Conenna, I., Rocha, R., Russo, D. and Cabeza, M. (2017), Insular bats and research effort: a review of global patterns and priorities. Mam Rev, 47: 169–182. doi:10.1111/mam.12090.