Mariana Fruit Bat - Margaux Thys

Mariana Fruit Bat | Fanihi

Pteropus mariannus mariannus

Margaux Thys

BIO 227-01

Mariana fruit bat - Photo credit Dave Worthingtonl/USFWS 

Located only on the small Mariana Island chain, the Mariana Fruit Bat is an endangered subspecies of fruit bat critical to the composition of the islands. The species is seen on 14 of the 15 islands that make up the archipelago. Numbers began declining in the late 20^th century and were officially declared endangered in Guam in 1984. 

          As for their habitat requirements, the Fanihi are colonial and often live in groups of close trees so they need dense limestone forests. Additionally, if the bats move between the islands, there has to be enough trees to house in-transit bats. Being that the bats are herbivores, they need a variety of fruit, nectar, and pollen year round.

          There are five factors that determine that these bats are classified as endangered or threatened. At first only listed as endangered on Guam, their status has spread throughout the other islands.1 Factor A determines that their habitat is in fact being diminished by ungulate damage and invasion of exotic plants. This destruction significantly reduces the survival of the Fanihi populations.2

          Factor B includes the increasing effect of illegal hunting of the bats for local consumption. Hunting the the Fanihi was a common cultural practice, but with declining numbers, it was made illegal in the 1970’s. Contrary to this practice becoming illegal, they are still being hunted illegally.2

          Factor C states that the the Fanihi could have a potential predator in the Brown Tree snake. The snake preys on the young before they are able to fly properly. For the Mariana Fruit Bat, this is the least problematic factor in their status.2

          Factor D shows the of current law and enforcement in regards to the hunting of the Fanihi. Oftentimes, there is little investigation into poaching cases with even fewer convictions.2

          Factor E explores the effect of natural factors on the species, like the frequent typhoons on the island chains. Especially in the more recent years, one of the islands has been having volcanic eruptions. On the other hand, this factor explores man-made effects as well. For the Mariana Fruit Bat, certain habitats have been ruined by military test bombing and air force training areas. All of these continuous disturbances make it significantly more difficult for populations to recolonize extirpated islands.2

           For all endangered species, their recovery priority number determines the severity of their situation as well as their effect on human well-being. For the Fanihi, they have priority 9 on a scale of 1C (the highest with human effect) to 18 (the lowest). In this case, the Mariana Fruit Bat has a moderate degree of threat today with a high recovery potential.2

          In order to no longer be listed as endangered, the population and distribution would have to go up. They would also have to monitor the species after de-listing. The most crucial of the factors to delist the Mariana Fruit Bat would be factors A, B, C, and E. If all these criteria are met, the species would no longer be considered endangered.2

          Going off of the recovery criteria, there are certain recovery actions that have to be taken. Mainly, these actions to be taken include immediate actions against poaching and to rebuild habitats.

          With these processes, the species will hopefully be brought back to stable levels by 2030.2  

Mariana fruit bat - USFWS

To read more about the Fanihi, click here

1. http://ecos.fws.gov/docs/recovery_plan/100330.pdf

2. Group, Pacific Region Web Development. "Mariana Fruit Bat - Pacific Islands Fish and Wildlife Office." Mariana Fruit Bat - Pacific Islands Fish and Wildlife Office. N.p., 20 Sept. 2012. Web. 26 Nov. 2016.