Are growth forms consistent predictors of leaf litter quality and decomposability across peatlands along a latitudinal gradient?
Are growth forms consistent predictors of leaf litter quality and decomposability across peatlands along a latitudinal gradient?
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DOI：
10.1111/j.1365-2745.2005.01024.x
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发表时间：
2005-08-01
影响因子：
5.5
通讯作者：
Van Logtestijn, RSP
中科院分区：
文献类型：
--
作者：
Dorrepaal, E;Cornelissen, JHC;Van Logtestijn, RSP
植物生长形态被广泛用于预测环境变化对植物群落的影响，如气候变暖和氮沉降增加，以及物种变化对碳和养分循环的影响。我们调查了生长形式和模式之间的关系，在凋落物质量和分解是独立的环境条件和生长形式是否一样好，凋落物化学在预测decomposable.We使用的自然，纬度梯度在欧洲西北部作为一个空间模拟未来的温度和氮的可用性增加。我们的70种典型的泥炭藓为主的泥炭地筛选结果表明，泥炭藓，万年青和落叶灌木，禾本科和杂类草的落叶层在凋落物化学显着不同，所有的凋落物化学变量的生长形式的排名是独立的区域。生长形式之间的差异通常大于差异有关的环境gradient.After 8和20个月的室外，泥炭藓为基础的分解床，生长形式一般不同的可分解性，但这些模式随纬度而变化。泥炭藓凋落物分解速度慢于其他凋落物在所有地区，再次解释其高代表性的有机沉积物的泥炭地。杂类草凋落物一般分解最快，而其他生长形式之间的差异很小，特别是在较高的纬度。多元回归分析表明，生长形式是更好地预测落叶分解比化学变量在暖温带泥炭地与高氮负荷，但在亚北极，表示“低”之义我们的研究结果表明，环境变化在直接决定生态系统凋落物化学方面的重要性可能低于它们通过改变生长的相对丰度而产生的间接影响forms.然而，气候和营养的限制，在高纬度泥炭地促进趋同营养高效的植物性状，导致类似的分解率的血管生长形式，尽管在凋落物化学的差异。因此，在预测植物群落对生态系统功能的控制方面，生长型概念的有用性是有限的。
Plant growth forms are widely used to predict the effects of environmental changes, such as climate warming and increased nitrogen deposition, on plant communities, and the consequences of species shifts for carbon and nutrient cycling. We investigated whether the relationship between growth forms and patterns in litter quality and decomposition are independent of environmental conditions and whether growth forms are as good as litter chemistry at predicting decomposability.We used a natural, latitudinal gradient in NW Europe as a spatial analogue for future increases in temperature and nitrogen availability. Our screening of 70 species typical of Sphagnum-dominated peatlands showed that leaf litters of Sphagnum mosses, evergreen and deciduous shrubs, graminoids and forbs differed significantly in litter chemistry and that the ranking of the growth forms was independent of the region for all litter chemistry variables. Differences among growth forms were usually larger than differences related to the environmental gradient.After 8 and 20 months incubation in outdoor, Sphagnum-based decomposition beds, growth forms generally differed in decomposability, but these patterns varied with latitude. Sphagnum litters decomposed slower than other litters in all regions, again explaining its high representation in organic deposits of peatlands. Forb litters generally decomposed fastest, while the differences among the other growth forms were small, particularly at higher latitudes.Multiple regression analyses showed that growth forms were better at predicting leaf litter decomposition than chemical variables in warm-temperate peatlands with a high N-load, but less so in the subarctic, low-N region.Our results indicate that environmental changes may be less important in determining ecosystem leaf litter chemistry directly than are their indirect effects through changes in the relative abundance of growth forms. However, climatic and nutritional constraints in high-latitude peatlands promote convergence towards nutrient-efficient plant traits, resulting in similar decomposition rates of vascular growth forms despite differences in litter chemistry. The usefulness of the growth-form concept in predicting plant community controls on ecosystem functioning is therefore somewhat limited.