Context

Species dependent on freshwaters are declining globally. Understanding natural and anthropogenic environmental drivers affecting community structure and species occurrence is crucial for planning management and conservation actions.

Objectives

The aim of this study was to determine which landscape characteristics constrain reproductive guilds in wadeable streams and to explore the influence of reproductive strategy on fish occurrence. We expected reproductive guilds to differ in their associations with landscape determinants (i.e., the landscape characteristics found to constrain our reproductive guilds).

Methods

This study was conducted in the Delaware River Basin in North America. We compiled existing stream survey and geospatial data from multiple government agencies and scientific organizations for 552 sites. We used ordination and regression techniques to identify important landscape determinants and their associations with reproductive guilds.

Results

We identified 12 variables that explained 20.6% of the total variation in reproductive guild composition. Slope, land cover and disturbance variables drove the position of reproductive guilds in ordination space. All reproductive guilds differed in the set of landscape-scale determinants that were selected during modelling. Best subsets of variables selected in regression models indicate that reproductive guild occurrence is significantly explained by catchment characteristics. These characteristics include measures of slope, land use and land cover, disturbance, and climate.

Conclusions

Differences in determinants and relationships with reproductive guilds found in regression models, and gradients identified, indicate the importance of different landscape-scale determinants for specific reproductive guilds. Furthermore, our findings suggest a link between the environmental requirements of reproductive guilds and landscape-scale characteristics.

中文翻译：

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鱼类繁殖行会的景观决定因素

语境

全球依赖淡水的物种正在减少。了解影响社区结构和物种发生的自然和人为环境驱动因素对于规划管理和保护行动至关重要。

目标

这项研究的目的是确定哪些景观特征限制了涉水河流中的繁殖行会，并探讨了繁殖策略对鱼类繁殖的影响。我们期望生殖行会与景观决定因素的关联有所不同（即，发现的景观特征限制了我们的生殖行会）。

方法

这项研究是在北美特拉华河盆地进行的。我们汇总了来自多个政府机构和科学组织的552个站点的现有流调查和地理空间数据。我们使用排序和回归技术来确定重要的景观决定因素及其与繁殖行会的关联。

结果

我们确定了12个变量，这些变量解释了繁殖行会组成总变化的20.6％。坡度，土地覆盖和扰动变量驱动了生殖行会在有序空间中的位置。在建模过程中选择的景观尺度决定因素集合中，所有繁殖行会都不同。在回归模型中选择的变量的最佳子集表明，繁殖行会的发生由流域特征显着解释。这些特征包括坡度，土地利用和土地覆盖，扰动和气候的度量。

结论

在回归模型中发现的行列式及其与繁殖行会的关系以及确定的梯度的差异表明，不同景观尺度行列式对于特定繁殖行会的重要性。此外，我们的发现表明生殖行会的环境要求与景观尺度特征之间存在联系。