期刊
JOURNAL OF ECOLOGY
卷 95, 期 1, 页码 139-150出版社
BLACKWELL PUBLISHING
DOI: 10.1111/j.1365-2745.2006.01187.x
关键词
Alaska; Arctic tundra; carbon balance; CO2 flux; gross primary productivity; landscape heterogeneity; leaf area index; light response; normalized difference vegetation index; Sweden
资金
- Natural Environment Research Council [NE/D005795/1] Funding Source: researchfish
- NERC [NE/D005795/1] Funding Source: UKRI
1 The arctic environment is highly heterogeneous in terms of plant distribution and productivity. If we are to make regional scale predictions of carbon exchange it is necessary to find robust relationships that can simplify this variability. One such potential relationship is that of leaf area to photosynthetic CO2 flux at the canopy scale. 2 In this paper we assess the effectiveness of canopy leaf area in explaining variation in gross primary productivity (GPP): (i) across different vegetation types; (ii) at various stages of leaf development; and (iii) under enhanced nutrient availability. To do this we measure net CO2 flux light response curves with a 1 x 1 m chamber, and calculate GPP at a photosynthetic photon flux density (PPFD) of 600 mu mol m(-2) s(-1). 3 At a subarctic site in Sweden, we report 10-fold variation in GPP among natural vegetation types with leaf area index (LAI) values of 0.05-2.31 m(2) m(-2). At a site of similar latitude in Alaska we document substantially elevated rates of GPP in fertilized vegetation. 4 We can explain 80% of the observed variation in GPP in natural vegetation (including vegetation measured before deciduous leaf bud burst) by leaf area alone, when leaf area is predicted from measurements of normalized difference vegetation index (NDVI). 5 In fertilized vegetation the relative increase in leaf area between control and fertilized treatments exceeds the relative increase in GPP. This suggests that higher leaf area causes increased self-shading, or that lower leaf nitrogen per unit leaf area causes a reduction in the rate of photosynthesis. 6 The results of this study indicate that canopy leaf area is an excellent predictor of GPP in diverse low arctic tundra, across a wide range of plant functional types.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据