Context

Although hydropower development is one of the primary drivers of habitat loss and insular fragmentation, its impacts on species identity and their functional and phylogenetic roles have often been overlooked.

Objectives

Here we use an integrative approach, considering taxonomic, functional and phylogenetic dimensions at multiple scales, to understand the processes underlying species (dis)assembly of two taxa exhibiting relatively low dispersal ability: small mammals and lizards.

Methods

We surveyed 26 islands within the Balbina Hydroelectric Reservoir, and adjacent continuous forest, in Central Amazonia. Each dimension of diversity was related to spatial and habitat variables. We also examined functional composition using community-weighted mean trait values, and community redundancy using functional uniqueness. β-diversity was partitioned into their richness (β_rich) and replacement (β_repl) components.

Results

Functional and phylogenetic α-diversities of both taxa mirrored the taxonomic dimension, all of which increased with forest area. Individual small mammal (body mass and matrix tolerance), and lizard traits (body length, heliothermic mode and habitat type) were also predicted by forest area. For both groups, functional uniqueness decreased with forest area, and all dimensions of β-diversity were predominantly partitioned in β_rich.

Conclusions

The environmental filter created by forest area resulted in the low conservation value associated with small forest islands, only occupied by a small set of species comprised by generalist lizards and matrix-tolerant small mammals. On the other side, large forest sites ensured ecosystem resilience to disturbance. To maintain ecosystem integrity, creating myriad small islands over large expanses of floodwaters should be avoided in future hydropower development.

中文翻译：

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森林面积预测亚马逊岛屿森林碎片中小型哺乳动物和蜥蜴多样性的所有维度

上下文

尽管水电开发是栖息地丧失和岛屿破碎化的主要驱动因素之一，但其对物种特征及其功能和系统发育作用的影响往往被忽视。

目标

在这里，我们使用综合方法，在多个尺度上考虑分类学、功能和系统发育维度，以了解两种散布能力相对较低的分类群的物种（分解）组装过程：小型哺乳动物和蜥蜴。

方法

我们调查了亚马逊中部巴尔比纳水电站内的 26 个岛屿和邻近的连续森林。多样性的每个维度都与空间和栖息地变量有关。我们还使用社区加权平均特征值检查了功能组成，并使用功能唯一性检查了社区冗余。β多样性分配到他们的丰富性（β_丰富）和更换（β _REPL）组件。

结果

两种分类群的功能和系统发育 α 多样性反映了分类学维度，所有这些都随着森林面积的增加而增加。森林面积还预测了个体小型哺乳动物（体重和基质耐受性）和蜥蜴特征（体长、日热模式和栖息地类型）。对于这两个群体，功能独特性随着森林面积的增加而降低，并且β多样性的所有维度主要划分为_富含β 。

结论

森林面积造成的环境过滤导致与小森林岛屿相关的低保护价值，只有少数物种占据，包括通才蜥蜴和耐基质的小型哺乳动物。另一方面，大型林地确保了生态系统抵御干扰的能力。为了保持生态系统的完整性，在未来的水电开发中应避免在大面积的洪水中形成无数的小岛。