Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, Texas, USA.
Center for Global Change and Earth Observations, Michigan State University, East Lansing, USA.
Sci Rep. 2019 Nov 13;9(1):16684. doi: 10.1038/s41598-019-52243-0.
Land-cover change often shifts the distribution of biomass in animal communities. However, the effects of land-cover changes on functional diversity remain poorly understood for many organisms and ecosystems, particularly, for floodplains. We hypothesize that the biomass distribution of fish functional diversity in floodplains is associated with land cover, which would imply that fish traits affect behavioral and/or demographic responses to gradients of land cover. Using data from surveys of 462 habitats covering a range of land-cover conditions in the Amazon River floodplain, we fitted statistical models to explain landscape-scale variation in functional diversity and biomass of all fish species as well as subsets of species possessing different functional traits. Forest cover was positively associated with fish biomass and the strength of this relationship varied according to functional groups defined by life history, trophic, migration, and swimming-performance/microhabitat-use traits. Forty-two percent of the functional groups, including those inferred to have enhanced feeding opportunities, growth, and/or reproductive success within forested habitats, had greater biomass where forest cover was greater. Conversely, the biomass of other functional groups, including habitat generalists and those that directly exploit autochthonous food resources, did not vary significantly in relation to forest cover. The niche space occupied by local assemblages (functional richness) and dispersion in trait abundances (functional dispersion) tended to increase with forest cover. Our study supports the expectation that deforestation in the Amazon River floodplain affects not only fish biomass but also functional diversity, with some functional groups being particularly vulnerable.
土地覆盖的变化常常会改变动物群落中生物量的分布。然而，对于许多生物和生态系统，特别是对于洪泛区，土地覆盖变化对功能多样性的影响仍了解甚少。我们假设，洪泛区鱼类功能多样性的生物量分布与土地覆盖有关，这意味着鱼类特征会影响其对土地覆盖梯度的行为和/或种群响应。利用在亚马逊河洪泛区范围内的 462 个栖息地的调查数据，我们拟合了统计模型，以解释所有鱼类物种以及具有不同功能特征的鱼类物种子集的功能多样性和生物量的景观尺度变化。森林覆盖与鱼类生物量呈正相关，这种关系的强度根据生活史、营养级、洄游和游泳性能/小生境利用特征定义的功能组而有所不同。42%的功能组，包括那些被推断在森林生境中具有增强的觅食机会、生长和/或繁殖成功率的功能组，其生物量随着森林覆盖的增加而增加。相反，其他功能组，包括生境普遍适应的物种和直接利用自生食物资源的物种，其生物量与森林覆盖没有显著变化。当地集合体占据的生态位空间（功能丰富度）和特征丰度的分散度（功能离散度）往往随森林覆盖的增加而增加。我们的研究支持这样的预期，即亚马逊河洪泛区的森林砍伐不仅会影响鱼类生物量，而且会影响功能多样性，一些功能组特别容易受到影响。
