Altitudinal Change in LAI and Stand Leaf Biomass in Tropical Montane Forests: a Transect Study in Ecuador and a Pan-Tropical Meta-Analysis |
| |
Authors: | Gerald Moser Dietrich Hertel Christoph Leuschner |
| |
Institution: | 1.Plant Ecology, Albrecht von Haller Institute for Plant Sciences,University of G?ttingen,G?ttingen,Germany |
| |
Abstract: | Abstract
Leaf area index (LAI) is a key parameter controlling plant productivity and biogeochemical fluxes between vegetation and the
atmosphere. Tropical forests are thought to have comparably high LAIs; however, precise data are scarce and environmental
controls of leaf area in tropical forests are not understood. We studied LAI and stand leaf biomass by optical and leaf mass-related
approaches in five tropical montane forests along an elevational transect (1,050–3,060 m a.s.l.) in South Ecuador, and conducted
a meta-analysis of LAI and leaf biomass data from tropical montane forests around the globe. Study aims were (1) to assess
the applicability of indirect and direct approaches of LAI determination in tropical montane forests, (2) to analyze elevation
effects on leaf area, leaf mass, SLA, and leaf lifespan, and (3) to assess the possible consequences of leaf area change with
elevation for montane forest productivity. Indirect optical methods of LAI determination appeared to be less reliable in the
complex canopies than direct leaf mass-related approaches based on litter trapping and a thorough analysis of leaf lifespan.
LAI decreased by 40–60% between 1,000 and 3,000 m in the Ecuador transect and also in the pan-tropical data set. This decrease
indicates that canopy carbon gain, that is, carbon source strength, decreases with elevation in tropical montane forests.
Average SLA decreased from 88 to 61 cm2 g−1 whereas leaf lifespan increased from 16 to 25 mo between 1,050 and 3,060 m in the Ecuador transect. In contrast, stand leaf
biomass was much less influenced by elevation. We conclude that elevation has a large influence not only on the leaf traits
of trees but also on the LAI of tropical montane forests with soil N (nitrogen) supply presumably being the main controlling
factor. |
| |
Keywords: | elevation gradient LAI leaf biomass leaf lifespan leaf litter production specific leaf area tropical montane forest |
本文献已被 SpringerLink 等数据库收录! |
|