Determinants of macroinvertebrate diversity in headwater streams: regional and local influences
Determinants of macroinvertebrate diversity in headwater streams: regional and local influences
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DOI：
10.1046/j.1365-2656.2003.00711.x
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发表时间：
2003-05-01
影响因子：
4.8
通讯作者：
Paavola, R
中科院分区：
文献类型：
--
作者：
Heino, J;Muotka, T;Paavola, R
1.多样性的多尺度决定因素以及区域（RSR）和当地丰富度（LSR）之间的关系最近引起了越来越多的关注，但此类关于溪流生物的研究仍然很少。我们研究了芬兰 120 条源头溪流的 RSR、β-多样性、LSR 和当地环境变量之间的关系。八个排水系统的大小大致相似的区域被定义为区域，并对每个区域的 15 个溪流浅滩（=局部）进行了采样。2． RSR 与平均 LSR 表现出很强的正相关关系 (R-2 = 0.686)，并且在 RSR 观察到的范围内没有曲线迹象。 RSR 也与 beta 多样性呈正相关，尽管不显着 (r = 0.662)3。在逐步回归中，RSR 是进入模型的第一个变量，结合 RSR 和河宽的模型解释了 LSR 的 32.5% 的变化。如果从模型中省略 RSR，则河流宽度成为最重要的变量，其次是水 pH 值，它们合计占 LSR.4 变化的 20.6%。在区域内尺度上，不同的变量对于解释 LSR 的变化很重要。与 LSR 相关的因素反映了溪流大小、空间异质性、不利的水化学条件 (pH) 或大型无脊椎动物的有限资源基础（养分浓度）5。 RSR 在设定 LSR 上限方面的主要作用表明，北方水源流的大型无脊椎动物组合是不饱和的。这一发现得到了实验研究证据的支持，实验研究表明，河流大型无脊椎动物之间的竞争性相互作用仅在非常小的空间尺度上有效，并且通常通过频繁的干扰来防止竞争性排斥。然而，尽管 RSR 通常是对 LSR 影响最大的变量，但尚不清楚 RSR 是否始终对 LSR 设定限制，反之亦然。例如，整个地区普遍不利的水化学条件可能会导致当地丰富度水平较低和地点之间的物种周转率较低，最终导致区域物种库贫乏。6。这些发现并不否认当地因素的重要性，但强调了解河流底栖群落的组织需要同时检查多个空间尺度上普遍存在的因素。
1.Multiscale determinants of diversity and the relationship between regional (RSR) and local richness (LSR) have recently attracted increased attention, yet such studies on stream organisms remain scarce. We studied the relationships among RSR, beta-diversity, LSR and local environmental variables in 120 headwater streams in Finland. Approximately similar-sized areas of eight drainage systems were defined as regions, and 15 stream riffles (= locality) per region were sampled.2. RSR showed a strong positive relationship with mean LSR (R-2 = 0.686), and there was no sign of curvilinearity within the observed range of RSR. RSR was also positively, although non-significantly, related to beta-diversity (r = 0.662).3. In stepwise regression, RSR was the first variable to enter the model, and a model incorporating RSR and stream width explained 32.5% of variation in LSR. If RSR was omitted from the model, then stream width emerged as the most important variable, followed by water pH, which together accounted for 20.6% of variation in LSR.4. At the within-region scale, different variables were important in accounting for variation in LSR. Factors correlated with LSR reflected either stream size, spatial heterogeneity, adverse water chemistry conditions (pH), or a limiting resource base for macroinvertebrates (nutrient concentrations).5. The major role of RSR in setting the upper limit to LSR suggests that macroinvertebrate assemblages of boreal headwater streams are unsaturated. This finding is supported by evidence from experimental studies, where it has been shown that competitive interactions among stream macroinvertebrates are effective only at very small spatial scales, and competitive exclusion is prevented typically by frequent disturbances. However, although RSR was generally the most influential variable contributing to LSR, it is far from clear whether RSR consistently sets the limits to LSR, or vice versa. For instance, uniformly adverse water chemistry conditions across a region may lead to low levels of local richness and low species turnover among sites, leading eventually to an impoverished regional species pool.6. These findings do not deny the importance of local factors, but emphasize that understanding the organization of stream benthic communities requires simultaneous examination of factors prevailing at multiple spatial scales.