The dependency of highly endemic island floras on few potential pollinators in depauperate island faunas suggests that pollinators and seed dispersers may be crucial in the preservation of biodiversity in isolated oceanic islands. We discuss the hypothesis that flying foxes are “strong interactors” in South Pacific islands where they serve as the principal pollinators and seed dispersers, This suggests that the ongoing decline and ultimate extinction of flying fox species on Pacific islands may lead to a cascade of linked plant extinctions. We propose an empirical test of this hypothesis: comparisons of plant reproductive success in Guam, which has virtually lost its flying fox populations, and Samoa, where significant populations remain.

In February 1990, tropical cyclone Ofa struck Western Samoa with very strong winds (in excess of 200 km/hr). In December 1991, less than 22 months later, tropical cyclone Val struck the same area with similar intensity. In the moist lowland forest of the Tafua Rain Forest Reserve, Savai'i, Western Samoa, we examined the effects of the two cyclones on forest structure, tree mortality, and interspecific differences in damage. Average mortality of trees was high after both cyclones (28% and 33%, respectively). In one forest area, subject to a fire after the first storm, mortality was more than 90 percent.The frequency of uprooted trees was 3 1 percent after Ofa, but only 16 percent after Val. Uprooting was significantly more frequent among species lacking buttresses or stilt roots. As a combined effect of the two cyclones, the lowland forest of Tafua suffered a 53 percent tree mortality, with remaining standing trees being severely damaged (topped and with a substantial reduction of main branches). Average tree density dropped from an estimated 476 trees/ha (> 5 cm DBH), before Ofa to 225 trees/ha after Val. Existent gap sizes are reflected by the changes in mean canopy cover which decreased from nearly 100 percent before Ofa to 27 percent after Val.Post-cyclone recovery is often observed to be very rapid, but the very large gaps created in the Tafua forest and the simultaneous loss of the whole guild of vertebrate seed dispersers (flying foxes and fruit pigeons) suggests it will be a long time before the upper canopy is once again closed. AUTUSa lavea Samoa e le afa o Ofa i Fepuari 1990 ma matagi malosi e sili atu ona saosaoa i le 200 km/itula. Ae le'i atoa le 22 masina, sa toe lavea Samoa e le afa o Val i Tesema, 1991. Sa matou su'esu'e i le tulaga sa 0'0 ai le vao matua o Tafua, ae maise i tulaga o le fa'amateina o la'au 'ese'ese. E tele la'au sa mate ai ona o na afa e lua, e tusa ma le 28% i le afa muamua ma le 33% i le afa lona lua. I se tasi itu o le vao o Tafua sa mu, sa mate ai le 90% o la'au. Sa pa'u ai 3 1% o la'au mai Ofa, ae na'o le 16% mai Val. 0 le tele o ia la'au sa pa'u, sa leai ni a'a lagolago poco a'a mai luga, ae na'o a'a i lalo le palapala. Ona o na afa e lua sa mate ai 53% o la'au i Tafua, ma sa leaga ai le tele o isi la'au o totoe. Sa pa'u le numera o la'au ae le'i agi ai na afa mai le 476 la'au/hectare (> 5 cm le mafia) i le 225 la'au/hectare ina ua mavae Val. E i ai va i le 27% o le vao ina ua mavae Val. 0 nisi taimi e vave ona toe tupu ai le vao mai afa fa'apea, ae aua nei va tele i le vao atoa ma le fa'mateaina o manu e feavea'i fatu (pe'a ma lupe), aronu olea umi se taimi se'ia toe lelei ai le vao matua o Samoa.

The South Pacific islands of Samoa have two extant flying fox species, Pteropus samoensis and P. tonganus. Following two severe cyclonic storms, we examined their differential behavioral responses and evaluated the effectiveness of recently established reserves in providing refugia. Although the cyclones disrupted activity patterns and foraging behavior for both species, comparisons with pre‐storm data suggested that the more common, widely distributed P. tonganus experienced more severe population declines than the endemic P. samoensis. This differential mortality could be explained by a combination of ecological and behavioral 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 appeared to use survival strategies not observed in P. tonganus. Leaves, which were far more available than flowers or fruits in the immediate 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‐resistant native liana, (Freycinetia reineckei). In contrast, a seasonally important food of P. tonganus is nectar from the delicate flowers of Syzygium inophylloides (asi), a canopy tree that is very vulnerable to wind damage and has become increasing scarce with the clearing of lowland forest. Rainforest reserves, established prior to the storms, served as adequate refugia for local P. samoensis populations, which appeared to feed relatively close to their roosts, primarily in native forest, but did not protect P. tonganus populations, which traveled outside reserves to forage in areas lacking hunting bans. Although wind damage was patchy and not consistent between storms, areas of high topographic complexity (e.g., volcanic cones and deep valleys) were the most likely to retain areas with some foliage and should be given priority in the design of future reserves.