Light environment and tree strategies in a Bolivian tropical moist forest: an evaluation of the light partitioning hypothesis |
| |
Authors: | Poorter Lourens Arets Eric J.M.M. |
| |
Affiliation: | (1) Programa Manejo de Bosques de la Amazonía Boliviana (PROMAB), Casilla, 107, Bolivia;(2) Forest Ecology and Forest Management Group, Department of Environmental Sciences, Wageningen University, 6700 AH Wageningen, The Netherlands;(3) Department of Plant Ecology, Utrecht University, 3508 TB Utrecht, The Netherlands |
| |
Abstract: | Light partitioning is thought to contribute to the coexistence of rain forest tree species. This study evaluates the three premises underlying the light partitioning hypothesis; 1) there is a gradient in light availability at the forest floor, 2) tree species show a differential distribution with respect to light, and 3) there is a trade-off in species performance that explains their different positions along the light gradient. To address these premises, we studied the light environment, growth, and survival of saplings of ten non-pioneer tree species in a Bolivian moist forest. Light availability in the understorey was relatively high, with a mean canopy openness of 3.5% and a mean direct site factor of 6.8%. Saplings of two light demanding species occurred at significantly higher light levels than the shade tolerant species. The proportion of saplings in low-light conditions was negatively correlated with the successional position of the species. Light-demanding species were characterised by a low share of their saplings in low-light conditions, a high sapling mortality, a fast height growth and a strong growth response to light. These data show that all three premises for light partitioning are met. There is a clear gradient in shade-tolerance within the group of non-pioneer species leading to a tight packing of species along the small range of light environments found in the understorey. This revised version was published online in August 2006 with corrections to the Cover Date. |
| |
Keywords: | Bolivia Hemispherical photographs Irradiance Niche differentiation Sapling growth Shade tolerance |
本文献已被 SpringerLink 等数据库收录! |
|