PARENT SESSION
Oral Session #52: Plant Ecology: Light and Carbon Allocation.
Presiding: T. Day
Wednesday, August 7. 8:00 AM to 11:30 AM. Gila Meeting Room, TCC.
Canopy microclimate: a vascular epiphyte's perspective.
Cardelús, Catherine*,1, Chazdon, Robin2, 1 University of Connecticut, Storrs, CT2 University of Connecticut, Storrs, CT
ABSTRACT- We compared photon flux density, air temperature, and relative humidity on branches in the lower canopies of two emergent tree species, Lecythis ampla and Hyeronima alchorneoides , at La Selva Biological Station, Costa Rica. Eight contiguous 0.5m x 0.5m quadrats were laid along two canopy branches in four individuals per species. Within quadrats, we recorded wet and dry bulb temperatures and PFD during wet and dry seasons of L. ampla and H. alchorenoides and the deciduous phase of L. ampla. Vascular epiphyte species and abundance were recorded for each plot. PFD (%-full sun) differed significantly between species, but not between seasons (p = 0.000 for species; p = 0.249 for season). Average PFD in L. ampla canopies (10-11%) was twice as high as in H. alchorneoides (5-6%). Relative humidity and temperature also varied significantly between species (p =0.001) and seasons (p = 0.000). During the deciduous phase the average daily PFD in L. ampla canopies reached 23.25% of full sun, 4 times that of H. alchorneoides. Within both species, individual trees showed significant variation in all microclimate variables. Vascular epiphyte species distributions overlap considerably between tree species, although distribution within tree branches is highly correlated with tree characteristics and microclimate.
KEY WORDS: Canopy microclimate, Epiphyte, Tropical Rainforest