Impacts of ecosystem engineers on community attributes: effects of cushion plants at different elevations of the Chilean Andes
Impacts of ecosystem engineers on community attributes: effects of cushion plants at different elevations of the Chilean Andes
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DOI：
10.1111/j.1366-9516.2006.00248.x
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发表时间：
2006-07-01
影响因子：
4.6
通讯作者：
Cavieres, Lohengrin A.
中科院分区：
文献类型：
--
作者：
Badano, Ernesto I.;Cavieres, Lohengrin A.
生态系统工程师是能够调节环境力量的生物体，因此可能改变其他物种的栖息地条件。这样做，生态系统工程师可能会影响物种丰富度和群落均匀度，从而改变物种多样性。如果群落属性的这些变化与工程师引起的栖息地变化的程度有关，那么工程物种似乎可能会对引起较大栖息地变化的地点的多样性产生更大的影响。我们通过评估三种高山垫层植物对安第斯高山植物群落物种丰富度、均匀度和多样性的影响来解决这个问题。鉴于垫层与外部环境之间的小气候条件差异随着海拔的增加而增加，我们认为这些生物对高海拔地点的群落属性的影响应该大于低海拔地点的影响。结果表明，三种垫层物种对植物群落的物种丰富度、多样性和均匀度具有积极影响。还观察到这些影响的大小随海拔的变化而变化：对于三种垫层物种来说，对物种丰富度和多样性的积极影响随着海拔的升高而增加，而对于一种垫层物种来说，对均匀度的积极影响随着海拔的升高而增加，但对于其他两种垫层物种来说，随着海拔的升高而减少。这些结果表明，垫层的存在对于维持安第斯山脉高地群落的植物多样性很重要，但随着垫层与外部环境之间的环境条件差异随着海拔的增加而增加，这种对多样性的积极影响似乎也会增加。
Ecosystem engineers are organisms able to modulate environmental forces and, hence, may change the habitat conditions for other species. In so doing, ecosystem engineers may affect both species richness and evenness of communities and, in consequence, change species diversity. If these changes in community attributes are related to the magnitude of the habitat changes induced by the engineers, it seems likely that engineer species will have greater effects on diversity in sites where they cause larger habitat changes. We addressed this issue by evaluating the effects of three alpine cushion plants on species richness, evenness, and diversity of high-Andean plant communities. Given that the difference in microclimatic conditions between cushions and the external environment increases with elevation, we proposed that these organisms should have greater effects on community attributes at higher than at lower elevation sites. Results showed that the three cushion species had positive effects on species richness, diversity, and evenness of plant communities. It was also observed that the magnitude of these effects changed with elevation: positive effects on species richness and diversity increased towards upper sites for the three cushions species, whereas positive effects on evenness increased with elevation for one cushion species but decreased with elevation for other two cushion species. These results suggest that the presence of cushions is important to maintain plant diversity in high-Andean communities, but this positive effect on diversity seems to increase as the difference in environmental conditions between cushions and the external environment increases with elevation.