A flood plain palm forest in the Luquillo Mountains of Puerto Rico five years after Hurricane Hugo

Abstract

Long-tcrm smdif's are needed to undersrand rhc dynamics of tropical forests, particularly those subject to pcriodic disturbances such as hurricanes. We studied a flood plain Prestoea montana palm forest in the Luquillo Mountains of Puerro Rico over a 15-yr period (1980-1995), which included the passage of Hurricane Hugo in September 1989. The passage of the hurricane caused the dominant species to become more dominant and created low instamaneous rree morrality (1 o/o of stems) and reductions in tree biomass (-16 Mg/ha/yr) and density, although not in basal area. Five years after the hurricane, the palrn flood plain forest had exceeded its prehurricane aboveground tree biornass, tree density, and basal area. Aboveground tree biornass accurnulated at a rate of 9.2 Mg/ha/yr, 76 percem of which was due to pahns. Before the hurricane rhis rate was on the order of 3 Mg/ha/yr. Forest !loor litter decreased to prehurricane lcvds (6.7 Mg/ha), within 5 yr, mosdy due to the disappearance of woody litter. Thirreen tree spccics nor rcprescnred in rhe canopy emered the frircst by regeneration, and 2 specics suffcred almost 20 percent/yr rnortality over a 5-yr period after the storrn (floodplain average of 2%/yr). Delayed rree rnorrality was twice as high as instafl-· taneous t.rec mortality after the storrn and affected dicotyledonous trees more rhan ir did palrns. Regeneration of dicotyledonous trccs, palrns, and tree ferns was influenced by a cornbination of factors including hydroperiod, light, and space. Redundancy Data Analysis showed rhar the area near the river channel was rhe most favorable for planr regeneration. Palrn regeneration was higher in locations with longer hydroperiods, while regeneration of dicotyledonous trees was higher in areas with low risk of flooding. This study shows how a periodic disturbance provides long-term opportunities for species invasions and long-terrn ecosystern response at the patch scale of < 1 ha.

Citation

Frangi, J.L.; Lugo, A.E. 1998. A Flood Plain Palm Forest in the Luquillo Mountains of Puerto Rico Five Years After Hurricane Hugo. Biotropica. 30(3): 339-348.