Data from: Relationships between forest cover and fish diversity in the Amazon River floodplain

1.Habitat degradation leads to biodiversity loss and concomitant changes in ecosystem processes. Tropical river floodplains are highly threatened by land cover changes and support high biodiversity and important ecosystems services, but the extent to which changes in floodplain land cover affect fish biodiversity remains unknown. 2.We combined fish and environmental data collected in situ and satellite-mapped landscape features to evaluate how fish species with different ecological strategies and assemblage structures respond to deforestation in floodplains of the Amazon River. We surveyed 462 floodplain habitats distributed along a gradient of land cover, from largely forested to severely deforested. Rather than analyze only taxonomic metrics, we employed an integrative approach that simultaneously considers different aspects of fish biodiversity (i.e., beta diversity and taxonomic and functional assemblage structure) to facilitate mechanistic interpretations of the influence of land cover. 3.Spatial patterns of fish biodiversity in tropical floodplain rivers were strongly associated with forest cover as well as local environmental conditions linked to landscape gradients. Several species and functional groups defined by life history, feeding, swimming/microhabitat-use strategies were positively associated with forest cover. Other species, including some that would usually be considered habitat generalists and species directly dependent on autochthonous resources (e.g., planktivores), were most common in areas dominated by herbaceous vegetation or open-water habitats associated with the opposite extreme of the forest cover gradient. Beta-diversity and the degree of uniqueness of species combinations within habitats were also positively associated with forest cover. 4.Synthesis and applications. Our results, demonstrating that spatial patterns of fish biodiversity are associated with forest cover, indicate that deforestation of floodplains of the Amazon River results in spatial homogenization of fish assemblages and reduced functional diversity at both local and regional scales. Floodplains worldwide have undergone major land cover changes, with forest loss projected to increase during the next decades. Conserving fish diversity in these ecosystems requires protecting mosaics of both aquatic habitats and floodplain vegetation, with sufficient forest cover being critically important.1. 生境退化可引发生物多样性丧失，并伴随生态系统过程的改变。热带河流洪泛平原极易受到土地覆被变化的威胁，同时承载着极高的生物多样性与重要的生态系统服务功能，但目前学界仍未明确洪泛平原土地覆被变化对鱼类生物多样性的影响程度。 2. 本研究结合原位采集的鱼类与环境数据，以及卫星测绘的景观特征，旨在评估不同生态策略与集合群结构的鱼类物种对亚马孙河洪泛平原森林砍伐的响应模式。我们共调查了462处洪泛平原生境，这些生境分布于土地覆被梯度之上，覆盖了从近乎原始森林到严重砍伐的全部区间。本研究并未仅分析分类学指标，而是采用了整合研究方法，同时考量鱼类生物多样性的多个维度——即β多样性（beta diversity）、分类学与功能集合群结构——以助力解析土地覆被影响的内在机制。 3. 热带洪泛平原河流的鱼类生物多样性空间格局，与森林覆被以及与景观梯度相关的局域环境条件密切相关。若干基于生活史、摄食、游动/微生境利用策略划分的物种与功能群，与森林覆被呈正相关关系；另有部分物种（包括部分通常被视为广适性的物种，以及直接依赖内源资源的物种，如浮游生物食性鱼类）则在以草本植被或与森林覆被梯度另一端对应的开阔水域生境为主的区域更为常见。生境内部的β多样性与物种组合独特性，同样与森林覆被呈正相关关系。 4. 综合与应用。本研究结果表明，鱼类生物多样性的空间格局与森林覆被密切相关，这意味着亚马孙河洪泛平原的森林砍伐会导致鱼类集合群的空间均质化，并降低局域与区域尺度的功能多样性。全球范围内的洪泛平原均已发生大规模土地覆被变化，且未来数十年内森林砍伐预计还将加剧。要保护这些生态系统中的鱼类多样性，就需要同时保护水生境与洪泛平原植被的镶嵌体，而充足的森林覆被则是其中的关键要素。