DISSERTATION RESEARCH: Fish assemblage structure and functional trait diversity along a longitudinal fluvial gradient

了解环境因素与生态群落中生物特征的关系有助于揭示驱动多样性模式的重要过程。与摄食、栖息地利用或繁殖相关的功能特征可以沿着环境梯度进行检查，以研究栖息地变量如何在多个空间尺度上影响群落组成。在这项研究中，这种方法将用于比较Río Grijalva（墨西哥南部的一个大型热带河流盆地）纵向梯度的鱼类群落。鱼类的功能特征将与一系列环境变量一起在一系列栖息地的研究地点进行检查，从高地支流到广阔的低地泻湖。随着栖息地环境变得不那么恶劣，食物资源更加丰富，预计性状的多样性将从上游到下游增加。本研究对研究区及其他热带河流的保护具有重要意义。很少有研究在整个流域范围内检查热带鱼群落的变化，并且对环境差异如何影响功能特征知之甚少。关注环境因素如何影响鱼类群落将为评价物种引进、蓄水和其他形式的生境退化的影响提供有价值的信息。

An understanding of how environmental factors relate to the characteristics of organisms in ecological communities can help reveal important processes driving patterns of diversity. Functional traits associated with feeding, habitat use, or reproduction can be examined along environmental gradients to investigate how habitat variables influence community composition at multiple spatial scales. In this study, such an approach will be used to compare fish communities along a longitudinal gradient in the Río Grijalva, a large tropical river basin in southern Mexico. Functional traits of fishes will be examined along with a suite of environmental variables in study sites across a range of habitats, from upland tributary streams to broad, lowland lagoons. The diversity of traits is expected to increase from upstream to downstream as habitats become less environmentally harsh and food resources are more plentiful.This research has important implications for conservation in this study region and in other tropical rivers. Few studies have examined changes in tropical fish communities at the scale of an entire watershed, and little is known about how environmental differences affect functional traits. A focus on how environmental factors influence fish communities will provide valuable information for evaluating the effects of species introductions, impoundments, and other forms of habitat degradation.