Manipulative whole-pond experiments to examine the ecosystem-level effects of pesticide applications

在这项研究中，我们将使用全生态系统实验来研究一种常见的化学除草剂对水生群落的影响。我们在自然系统中这样做，我们可以探索肥料投入和捕食如何与除草剂作用相互作用。直到最近，草甘膦（即RoundUp和Vision），一种广泛用于控制林业、农业和军事设施植被的化学除草剂，被许多人认为是一种相对无害的除草剂。新的研究表明，草甘膦对环境的负面影响可能比之前所怀疑的要大。然而，结果一直不明确，很大程度上是因为实验是在小型人工系统中进行的，无法捕捉到自然界中存在的所有空间、时间和生物异质性。我们有一个独特的机会，在新不伦瑞克省南部的CFB Gagetown建立了一套36个实验池塘，以确定草甘膦对自然系统的影响，这些系统捕获了自然界中发现的所有复杂性。我们将进行重复实验，用不透水的窗帘将所有池塘分成两半，对一半进行处理，而另一半不进行处理作为对照。治疗将包括草甘膦在预测（即最坏情况）和实际环境浓度下，单独或与农业肥料和两栖动物的天敌结合使用。我们将研究这些处理对各种水生生物的影响，包括浮游植物、大型植物和无脊椎动物，但这项工作的主要重点将放在两栖动物身上，因为它们独特的发育生物学、生理学和作为环境胁迫指标的潜力。我们将进行测试，看看新的草甘膦配方，单独使用或与肥料和捕食者结合使用，是否会对两栖动物的基因表达、激素水平、繁殖力、存活率、性别比例、患病率、畸形、丰度和物种丰富度产生影响。我们的合作伙伴国防部和加拿大林务局将利用这些成果制定流域管理计划。

In this study we will use whole-ecosystem experiments to examine the effects of a common chemical herbicide on aquatic communities. We do this in natural systems where we can explore how fertilizer inputs and predation interact with herbicide effects. Until recently, glyphosate (i.e. RoundUp and Vision), a chemical herbicide that is widely-used to control vegetation in forestry, agriculture, and on military installations, was considered by many to be a relatively benign herbicide. New research suggests that glyphosate may have greater negative environmental impacts than had previously been suspected. However, the results have been ambiguous, in large part because the experiments were carried out in small artificial systems that cannot capture all of the spatial, temporal and biological heterogeneity present in nature. We have the unique opportunity to establish a set of 36 experimental ponds at CFB Gagetown in southern New Brunswick to determine the effects of glyphosate in natural systems that capture all the complexity found in nature. We will conduct replicated experiments with all ponds separated into two halves by an impermeable curtain and treatments applied to one half while the other half is left untreated as a control. Treatments will include glyphosate at predicted (i.e. worst case scenario) and realistic environmental concentrations, alone and in combination with agricultural fertilizers and natural predators of amphibians. We will examine impacts of these treatments on a variety of aquatic organisms, including phytoplankton, macrophytes, and invertebrates, but the primary emphasis of this work will be on amphibians because of their unique developmental biology, physiology and potential as indicators of environmental stress. We will be testing to see if new glyphosate formulations, alone or in combination with fertilizers and predators, have effects on amphibian gene expression, hormone levels, fecundity, survival, sex ratios, disease prevalence, deformities, abundance and species richness. These results will be used by our partners, the Department of National Defence and Canadian Forest Service to develop watershed management plans.