INITIAL RESULTS OF A LONG-TERM CORAL-REEF MONITORING PROGRAM - IMPACTOF HURRICANE HUGO AT BUCK ISLAND REEF NATIONAL MONUMENT, ST-CROIX, UNITED-STATES VIRGIN-ISLANDS

Fixed position linear transects were established in early 1989 at Buck Island Reef National Monument, St. Croix, U.S. Virgin Islands. On Sep tember 17-18 of that year Hurricane Hugo, the most severe cyclone to i mpact the area in over 60 years, passed directly over the island bring ing hurricane-force winds for over 12 h and maximum estimated wind spe eds of 70 m . s-1 (160 mph). Despite the severity of the storm, damage to coral reefs was extremely localised and concentrated mainly on ree fs open to its southeasterly direction of approach. The southeast reef front at Buck Island was razed to substrate level between the surface and 7 m depth and the reef crest behind it was smothered in a 1 m dee p berm of broken coral rubble. At a site on the north backreef, howeve r, only a slight loss of coral cover was detected which was more than compensated for during 1990-91. At a south reef site which was in 8-10 m depth, just outside the region of severe damage, coral cover was re duced by 40-46% on three out of four transects. Shifts in community st ructure were detected by multi-dimensional scaling of Bray-Curtis simi larity measures and by k-dominance curves, but not by the Shannon dive rsity statistic (H'). Coral cover had returned to approximate pre-hurr icane levels by June 1991, but community composition remained distinct . One of the four transects at this south site was apparently not sign ificantly damaged during the hurricane. Such spatial variability may a ffect recovery rates, since pockets of relatively undisturbed benthos may provide seed populations for recruitment into adjacent, more sever ely damaged areas. Hurricane Hugo did not appear to cause an immediate increase in species diversity by differential mortality of the domina nt species in the community. This result is consistent with previous s tudies of the impact of less severe storms on St. Croix. but contrary to several reports of hurricane impact in other areas.