MICROTOPOGRAPHIC HETEROGENEITY AND FLORISTIC DIVERSITY IN EXPERIMENTAL WETLAND COMMUNITIES
MICROTOPOGRAPHIC HETEROGENEITY AND FLORISTIC DIVERSITY IN EXPERIMENTAL WETLAND COMMUNITIES
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DOI：
10.2307/2960628
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发表时间：
1997-02
影响因子：
5.5
通讯作者：
G. Vivian‐Smith
中科院分区：
文献类型：
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作者：
G. Vivian‐Smith
[1]由于种间生境偏好的差异，在异质环境中共存被认为是容易的。微地形异质性是影响淡水湿地群落多样性的重要因素。我测试是否存在种间差异，不同的微地形位置的栖息地偏好，以及是否多样性与小规模的空间微地形异质性在实验湿地社区。2我操纵微地形异质性产生“均匀”（平坦表面）和“异质”（丘状凹陷）处理。三个繁殖体来源的处理（种子库，种子，种子库+种子），以确定是否异质性的反应取决于繁殖体的来源。栖息地的偏好内异质处理的微栖息地确定为每个物种通过记录的个人数量位于“驼峰”或“空心”。通过测量丰富度、均匀度、物种丰度和地上生物量来量化对异质性和繁殖体来源的响应。3.微地形的小尺度变化（1-3 cm）导致植物群落结构的高度显著差异。植物区系多样性的两个组成部分，物种丰富度和均匀度，一直在社区异质微地形。4群落组成、个体丰度和地上生物量对异质性和繁殖体来源的响应存在差异。大多数物种达到更大的丰度在异质环境比同质环境，但是，物种同样丰富，在这两个包括Eleocharis ovata，泽泻triviale和三棱americanum。5在异质环境中生长的大多数物种表现出对丘状或中空微生境的明显生境偏好，许多稀有物种，特别是木本多年生植物，更喜欢丘状。
1 Coexistence is thought to be facilitated in heterogeneous environments due to interspecific differences in habitat preference. Microtopographic heterogeneity is a major factor structuring natural freshwater wetland communities and is thought to influence diversity. I tested whether interspecific differences existed in habitat preference for different microtopographic positions and whether diversity was associated with small-scale spatial microtopographic heterogeneity in experimental wetland communities. 2 I manipulated microtopographic heterogeneity to produce 'homogeneous' (flat surface) and 'heterogeneous' (hummock-hollow) treatments. Three propagule source treatments (seed bank, seeds, seed bank + seeds) were incorporated to determine if responses to heterogeneity depended on the propagule source. Habitat preferences for microhabitats within heterogeneous treatments were determined for each species by recording the number of individuals located on 'hummocks' or in 'hollows'. Responses to heterogeneity and propagule source were quantified by measuring richness, evenness, species abundances and above-ground biomass. 3 Small-scale variability in microtopography, on the order of 1-3 cm, produced highly significant differences in plant community structure. Both components of floristic diversity, species richness and evenness, were consistently greater in communities with heterogeneous microtopography. 4 Community composition, abundance of individuals and above-ground biomass responded differentially to heterogeneity and propagule source. Most species reached greater abundances in heterogeneous environments than homogeneous environments; however, species that were similarly abundant in both included Eleocharis ovata, Alisma triviale and Sparganium americanum. 5 Most species growing within the heterogeneous environments showed distinct habitat preferences for hummock or hollow microhabitats, with many rarer species, particularly woody perennials, favouring hummocks.