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 Se ptember 1989 Hufficane Hugo struck Puerto Rico, with the eye of the hu rricane 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 (Ar tibeus jamaicensis, Stenoderma rufum, and Menophyllus redmani) were ex amined for three years prior and three years after the hurricane. Popu lation levels as estimated by captures per net hour of all three speci es were affected by Hurricane Hugo. Populations of A. jamaicensis and M. redmani returned to predisturbance levels within two years. In cont rast, population levels of S. rufum declined to about 30 percent of pr ehurricane 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 prehurrican e size. The cost of foraging, in terms of time and energy, may be cons iderably elevated over prehurricane scenarios. In fact, a significant change in the age structure of the population (juvenile individuals ha ve been absent from the population since Hurricane Hugo) as well as si gnificant decline in rhe percent of reproductively active females indi cate a failure to reproduce in the posthurricane environment.