Understanding the key mechanisms that govern climber/hemiepiphyte responses to a hurricane

Abstract

International audienceQuestionIn dense tropical forests, climbers and hemiepiphytes depend on the quantity and quality of direct light more than other plant life forms. What are their responses with respect to quantitative changes of canopy structure and light regime after a hurricane? Here, we study their contribution to closure of the canopy and changes in light regime, with the help of hemispherical photography. Their change in space and time may serve as an illustration and measure of key processes after repetitive large disturbances.LocationMartinique, the Plateau Concorde, in an evergreen montane forest.MethodsAfter Hurricane Dean, a diachronic study (2008-2012) was carried out. Four parallel surface areas 50x10m were set up. Canopy structure and light conditions were assessed with hemispherical photographs, using a polar projection fisheye lens. All standing trees >5cm DBH, and all climbers and hemiepiphytes were mapped and identified to species. Correspondence analysis (CA) using selected life traits illustrated the distribution of climbers present on trees per category (a total of four). The number of individuals and species which have disappeared or appeared per category was calculated.ResultsFrom 2009 to 2012, the total number of climbers and hemiepiphytes decreased from 248 to 225, but in different proportions according to strata. Climbers were classified into categories in function of the range of responses (i.e. resistance and responsiveness).ConclusionOur study demonstrates the potential to detect climber/hemiepiphyte strategies after a large disturbance using hemispherical photography and plant traits