Post-Hurricane Responses of Climbers in a Tropical Mountain Rain Forest of Martinique
Schnitzler A; Arnold C; Fiard J; Joseph P
Hurricane Dean a category 4 storm impacted the forests along the western coast of Martinique on August 17 2007. In March 2008 plots were selected in the rainforest of the Plateau Concorde which presented a range of post-hurricane damage. The study focused on climber community patterns in two extreme ranges of disturbance (HIP: highly damaged plots; LIP: lightly damaged plots). The objectives of the study were to i) obtain data on forest architecture and light regime ii) determine the species diversity and abundance among climbers and iii) identify recurrent patterns of association among traits within this flora. Fisheye photos showed significant differences in canopy geometry and light microclimate between HIP and LIP. One transect in each extreme range of disturbance showed that the floors were similarly covered but the distribution of foliar density in the vertical structure was evenly distributed from the floor to the canopy in LIP and was exclusively concentrated within the first meter in HIP. Five hundred and eleven climbers were counted measured and identified in 12 plots (30 m?×?30 m). Correspondence analysis of the selected traits revealed four functional groups (C1 to C4). C1 and C2 included understory climbers and C3 and C4 were composed of overstory climbers showing differences in stem or leaf nature. We identified eight species among the 161 trees >5 cm dbh (diameter at breast height) assessed in the 12 plots supporting climbers. A linear regression showed that large trees were more colonized than smaller trunks. The mean number of climbers per host trunk was 2.7 with no significant difference between HIP and LIP plots. In spite of the great differences in forest architecture canopy openness and light regime the 16 climber species were present in all plots. Five species all belonging to one of the four functional groups varied in abundance. In the HIP plots the dramatic expansion of Cayaponia americana (C1) a ruderal plant frequently observed at lower altitudes was noteworthy. Our results suggest that climbers present highly efficient morphological adaptations to hurricanes. Indeed they are mostly linked to a single host they strongly reiterate after breakage and they show low clumping.