THE EFFECTS OF HURRICANE HUGO ON BATS OF THE LUQUILLO EXPERIMENTAL FOREST OF PUERTO-RICO

Natural disturbances can have large effects on ecosystem structure and function depending on their scale, intensity, and frequency. On 18 September 1989 Hufficane Hugo struck Puerto Rico, with the eye of the hurricane passing within 10 km of the Luquillo Experimental Forest. This provided a rare opportunity to evaluate the effects of an infrequent but large scale and high intensity disturbance on tropical bat species. Data on demographic parameters of three common phyllostomid bats (Artibeus jamaicensis, Stenoderma rufum, and Menophyllus redmani) were examined for three years prior and three years after the hurricane. Population levels as estimated by captures per net hour of all three species were affected by Hurricane Hugo. Populations of A. jamaicensis and M. redmani returned to predisturbance levels within two years. In contrast, population levels of S. rufum declined to about 30 percent of prehurricane levels and have not recovered after three years. Moreover, telemetry data indicate that foraging and home range size expanded to encompass an area approximately five times larger than its prehurricane size. The cost of foraging, in terms of time and energy, may be considerably elevated over prehurricane scenarios. In fact, a significant change in the age structure of the population (juvenile individuals have been absent from the population since Hurricane Hugo) as well as significant decline in rhe percent of reproductively active females indicate a failure to reproduce in the posthurricane environment.