EFFECTS OF TROPICAL CYCLONIC STORMS ON FLYING FOX POPULATIONS ON THE SOUTH-PACIFIC ISLANDS OF SAMOA

The South Pacific islands of Samoa have two extant flying fox species, Pteropus samoensis and P. tonganus. Following two severe cyclonic sto rms, we examined their differential behavioral responses and evaluated the effectiveness of recently established reserves in providing refug ia. Although the cyclones disrupted activity patterns and foraging beh avior for both species, comparisons with pre-storm data suggested that the more common, widely distributed P. tonganus experienced more seve re population declines than the endemic P. samoenis. This differential mortality could be explained by a combination of ecological and behav ioral factors. P. tonganus had a greater tendency to enter villages to feed on fallen cultivated fruits, making it more vulnerable to human hunting and predation by domestic animals. In addition, P. samoensis a ppeared to use survival strategies not observed in P. tonganus. Leaves , which were far more available than flowers or fruits in the immediat e post-storm period, comprised a major part of the post-storm diet of P. samoensis. This species also fed on the fleshy bracts of a storm-re sistant native liana, (Freycinetia reineckei). In contrast, a seasonal ly important food of P. tonganus is nectar from the delicate flowers o f Syzygium inophylloides (asi), a canopy tree that is very vulnerable to wind damage and has become increasing scarce with the clearing of l owland forest. Rainforest reserves, established prior to the storms, s erved as adequate refugia for local P. samoensis populations, which ap peared to feed relatively close to their roosts, primarily in native f orest, but did not protect P. tonganus populations, which traveled out side reserves to forage in areas lacking hunting bans. Although wind d amage was patchy and not consistent between storms, areas of high topo graphic complexity (e.g., volcanic cones and deep valleys) were the mo st likely to retain areas with some foliage and should be given priori ty in the design of future reserves.