Role and conservation of flying fox biodiversity for Fiji's rainforest health

The project was co-ordinated through the University of South Australia by Dr S. Petit.  Based in low- and mid-elevation tropical rainforest on Vanua Levu (Fiji Islands), the collaborative research involved the University of South Australia, University of South Pacific, University of Hawaii, National Trust of Fiji, and NatureFiji-MareqetiViti.  Annette Scanlon led the project in the field for two years, as a Ph.D. student at the University of South Australia.  Volunteer Guy Bottroff provided invaluable field assistance.  Other collaborators on the application were: Mr Alivereti Naikatini, Dr Don Drake, Dr Delene Weber, Dr Mark Stephens, and Ms Joan Gibbs.

Bat populations have been declining in the Pacific region because of habitat loss, hunting, cyclones, and lack of knowledge concerning their value and conservation management.  Elsewhere, bats have vast impacts on forest regeneration and health via pollination and seed dispersal, with positive feedback on the rest of the wildlife.  They are the only native mammals of many Pacific Island nations, including Fiji, where we conducted our research.  We aimed to determine some of the roles of bats in maintaining rainforest health in Fiji, and contribute to education and capacity of the local people, and to bat conservation. 

We:

  1. collected reproductive phenology data from primary and secondary rainforest over 24 months, including 12 months before and after a severe tropical cyclone (Cyclone Tomas, category 4) to examine resources for bats;
  2. studied the diet of Fiji’s rainforest’s plant-visiting bats (Pteropodidae) to identify pollination and seed dispersal roles;
  3. captured bats in low- and mid-elevation and cloud forests, and surveyed caves to determine the bats’ conservation status and threats; and
  4. assessed local people’s (focus groups and semi-structured interviews or conversations, workshops) and organised groups’ (mail-back surveys) perspectives and beliefs relating to bat conservation in Fiji.

The cyclone had an immediate negative effect on resources for frugivorous and nectarivorous fauna, including bats; non-tree resources were especially susceptible to the adverse impacts of the cyclone.  However, the primary and secondary forests demonstrated resilience to the cyclone at community level via increased flower survival (primary forest) and rapid flower production in a post-cyclone environment (secondary forest).  Overall, the density, abundance, and richness of resources for bats were lower in secondary forest than in primary forest.  The implications of reduced species richness of resources for bats in disturbed forests include compromised future resilience and response to disturbances, particularly for bat species with restricted dispersal ability and strong fidelity to forest sites.  We found that an invasive liana (Merremia peltata; Convolvulaceae) also reduced rainforest resources for bats, and influenced bat-plant interactions.

Our dietary analysis revealed that bats were vital for rainforest functions; they serviced (pollination, seed dispersal) at least 42% of species in a plant community.  In order to provide tangible evidence of the benefits of bat conservation to local people, we investigated the overlap between a plant assemblage benefiting from services of bats and that valued by humans (medicinal, cultural, economic uses).  The plant community was of high human value (75% of species had human-valued attributes) and we found a great overlap in bat-serviced and human-valued plants.  This approach demonstrates that tangible benefits of bats offer a powerful mechanism for targeting their conservation in traditionally-managed areas where negative attitudes towards bats may exist.

Five of the 6 bat species of Fiji were captured, with only one individual Mirimiri acrodonta (Critically Endangered) representing only the sixth recorded capture.  The failure to detect Emballonura semicaudata from any survey area raised immediate concern; the study provides evidence for a recommendation to an increased IUCN Red List category listing of Critically Endangered.  For example, we found the only large cave roost for the species (observed 10 years ago) was abandoned, and the cave vandalised.  Our assessment of attitudes regarding bats among locals and conservation organisations suggested that conservation programs must target ambivalent attitudes and focus on community engagement with key stakeholders.  Improved protection of caves and forests is urgent to ensure the long-term protection of Fijian bats.  However, cave environments ranked particularly poorly as priority habitats for conservation organisations working in Fiji, highlighting a need for differentiation among the goals of existing conservation groups and a new focus on cave protection and management.

Our work continues with the development of national guidelines for cave protection and management in Fiji, and dissemination of bat conservation information via workshops, online forums, scientific publications, and with the creation of extension material.

Associated publications

Scanlon, A.T. and Petit. S. 2015. Capture success of Fijian bats (Pteropodidae) and their evaluation as umbrella species for conservation. Pacific Conservation Biology, 21, 315-326. http://dx.doi.org/10.1071/PC15019.
Scanlon, A.T., Petit, S., Bottroff, G. (2013). The conservation status of bats in Fiji. Oryx, 48, 451-459.
Scanlon, A.T. 2014. The role and conservation of bats in Fiji’s rainforest. PhD Thesis, University of South Australia.
Scanlon, A.T., Petit, S., Sternberg, L.da S. 2013. Insectivory in Fijian flying foxes (Pteropodidae). Australian Journal of Zoology 61: 342-349.
Scanlon, A.T., Petit, S. 2013. How faecal sub-sampling methods affect the accuracy of dietary pollen detection. Journal of Mammalogy 94:1231-1330.
Scanlon, A.T. 2009. The long-tailed flying fox (Notopteris macdonaldi) on Viti Levu, Fiji. Australasian Bat Society Newsletter 32:17-19.
Scanlon, A.T. 2009. Survey for the Fiji Flying Fox (Mirimiri acrodonta) on Des Voeux Peak, Taveuni 2009. University of South Australia and NatureFiji-MareqetiViti, Suva.
Scanlon A.T. 2009. Fiji flying fox rediscovery. Australian Mammal Society Newsletter, 21-22.
Media release: “Rare bat captured on Taveuni”.  Fiji Sun Newspaper 21 June 2009.

Figure 1. Juvenile Pteropus samoensis subspecies nawaiensis

Figure 2. The critically endangered Fiji flying fox, Mirimiri acrodonta

Figure 3. Fiji long-tailed bat or Fiji blossom bat, Notopteris macdonaldi

Figure 4. Waisali village and rainforest area

Figure 5. Local children drawing bats at school