A Reexamination of the Relationships Among Phenological Complementarity,　Species Diversity, and Ecosystem Function

物候互補、物種多樣性與生態系統功能之間關係的再檢驗

覃光蓮(Guang-Lian Qin) ； 杜國禎(Guo-Zhen Du) ； 羅燕江(Yan-Jiang Luo) ； 董高生(Gao-Shen Dong) ； 馬建雷(Jiang-Yun Ma)

《Botanical Bulletin of Academia Sinica》 44卷3期 (2003/07) Pp. 239-244

https://doi.org/10.7016/BBAS.200307.0239

摘要

物種多樣性對生熊系統功能的影響近來引起了人們極大的興趣，許多研究得出結論：多樣性的增加能夠促進生態系統功能。理論預測二物候互補，即物種在資源利用和生長上的不同步，可以解釋多樣性是如何提高生熊系杭功能的，但遺沒有得到充分脆襲。本文拭圓弄清，在物梗矍富的自然植物群落中，(l)是否多樣性的增加促逸生熊系杭功能是通遇增加物候互補宣現的；②物候互補與a多樣性的關係如何。篇此，我們在天然的高寒草場一侗相對同矍的遺境中建立的55個永久樣方中進行育滕馨測，估豁了每個生長季中每個樣方中出現物梗的百分蓋度，實驗為期三年。每個樣方的物懂多樣性用糖物種敷和均勻度雨種方式度量，物候互補用方差比的對敷的魚敷來表示，生熊系統功能用年總蓋度(即一個生長季中每個物植所記綠下的最大蓋度之和)來衡量。年總蓋度，物種多樣性，物候互補關係的統計分析表明：年總蓋度隨著物種多樣性的增加而增加；物候互補能拘用來解釋物種多樣性封年糖蓄度的正效膺，但它與物種多樣性沒有顯著相關關係。這些結果表明：在我們研究高寒植物群落中，物候互補封年總蓋度的維持是關鍵的，然而，考慮到不同的物種共存樓制(比如，局域相似性等)，在物懂矍富的植物群落中，物候互補可能典a多樣性不必腺性相朋。此外，其他櫻制，比如物候互補的取樣效膺，可能也在物候互補促逸生熊系抗功能中同峙癸揮著作用。因此，更好地理解物候互補、物種多樣性對生熊系抗功能的影響將需要更廣泛的育滕以控制情成效應。

關鍵字

高寒草場 ； 生態系統功能 ； 均勻度 ； 物候互補 ； 物種多樣性 ； 方差比

並列摘要

Interest in the effects of species diversity on ecosystem function has been rapidly increasing, and many studies have concluded that increasing species diversity improves ecosystem function. Theories predict that pheno-logical complementarity, the asynchrony of species resource use and growth, may explain how species diversity enhances ecosystem function but it remains largely untested. In this paper, we tried to determine: (i) whether, in a species-rich natural assemblage, increasing species diversity enhances ecosystem function by increasing phenological complementarity, and (ii) how phenological complementarity was related to the scales of alpha- diversity. Over a three-year period, we conducted the experiment in 55 permanent plots with a relatively homogeneous environment in natural alpine grasslands, and estimated percent cover of each plant species present in each plot three times in each growing season. Species diversity in each permanent plot was quantified in two ways, the total number of species, and the evenness of species abundance. Phenological complementarity was quantified as the negative logarithm of the variance ratio. Ecosystem function was measured as total annual cover (i.e. the sum of maximum cover values recorded for each species in a growing season). Statistical analysis of the relationships between total annual cover, species diversity, and phenological complementarity found that total annual cover increased with species diversity, and phenological complementarity was responsible for the positive effects of species diversity on total annual cover. Phenological complementarity, however, was not significantly related to species diversity. These results indicate that phenological complementarity was critical to the maintenance of total annual cover in our studied alpine plant communities. However, considering different mechanisms of species coexistence (e.g.local similarity), phenological complementarity is not necessarily linearly correlated with the scales of alpha-diversity in species- rich plant assemblages. In addition, other mechanisms, for example, the sampling effect for phenological complementarity, may simultaneously act on how phenological complementarity enhances ecosystem function. Therefore, greater understanding of how diversity and phenological complementarity influence ecosystem function will require more extensive experiments that control the effects of composition.

並列關鍵字

Alpine grassland ； Ecosystem function ； Evenness ； Phenological complementarity ； Species diversity ； Variance ratio.