Levis Nicholas A, Johnson Jarrett R
Department of Biology, Western Kentucky University, Bowling Green, KY, 42101, USA,
Ecotoxicology. 2015 Jul;24(5):1073-86. doi: 10.1007/s10646-015-1448-2. Epub 2015 Mar 21.
Glyphosate-based herbicides are the number one pesticide in the United States and are used commonly around the world. Understanding the affects of glyphosate-based herbicides on non-target wildlife, for example amphibians, is critical for evaluation of regulations pertaining to the use of such herbicides. Additionally, it is important to understand how variation in biotic and abiotic environmental conditions, such as UV-B light regime, could potentially affect how glyphosate-based herbicides interact with non-target species. This study used artificial pond mesocosms to identify the effects of generic glyphosate-based herbicide (GLY-4 Plus) on mortality, cellular immune response, body size, and morphological plasticity of larvae of the spotted salamander (Ambystoma maculatum) under conditions that reflect moderate (UV(M)) and low (UV(L)) UV-B light regimes. Survival within a given UV-B level was unaffected by herbicide presence or absence. However, when herbicide was present, survival varied between UV-B levels with higher survival in UV(M) conditions. Herbicide presence in the UV(M) treatments also decreased body size and reduced cellular immune response. In the UV(L) treatments, the presence of herbicide increased body size and affected tail morphology. Finally, in the absence of herbicide, body size and cellular immune response were higher in UV(M) treatments compared to UV(L) treatments. Thus, the effects of herbicide on salamander fitness were dependent on UV-B level. As anthropogenic habitat modifications continue to alter landscapes that contain amphibian breeding ponds, salamanders may increasingly find themselves in locations with reduced canopy cover and increased levels of UV light. Our findings suggest that the probability of surviving exposure to the glyphosate-based herbicide used in this study may be elevated in more open canopy ponds, but the effects on other components of fitness may be varied and unexpected.
草甘膦基除草剂是美国使用量排名第一的农药，在全球范围内也被广泛使用。了解草甘膦基除草剂对非靶标野生动物（如两栖动物）的影响，对于评估此类除草剂使用的相关规定至关重要。此外，了解生物和非生物环境条件的变化（如UV - B光照条件）如何潜在地影响草甘膦基除草剂与非靶标物种的相互作用也很重要。本研究使用人工池塘中型生态系统，来确定通用草甘膦基除草剂（GLY - 4 Plus）在反映中等（UV(M)）和低（UV(L)）UV - B光照条件下，对斑点钝口螈（Ambystoma maculatum）幼体的死亡率、细胞免疫反应、体型和形态可塑性的影响。在给定的UV - B水平下，存活率不受除草剂存在与否的影响。然而，当存在除草剂时，UV - B水平之间的存活率有所不同，在UV(M)条件下存活率更高。UV(M)处理中除草剂的存在也减小了体型并降低了细胞免疫反应。在UV(L)处理中，除草剂的存在增加了体型并影响了尾部形态。最后，在没有除草剂的情况下，UV(M)处理中的体型和细胞免疫反应比UV(L)处理更高。因此，除草剂对蝾螈健康的影响取决于UV - B水平。随着人为栖息地的改变不断改变包含两栖动物繁殖池塘的景观，蝾螈可能越来越多地处于树冠覆盖减少和紫外线水平增加的环境中。我们的研究结果表明，在树冠更开阔的池塘中，存活于本研究中使用的草甘膦基除草剂暴露环境中的概率可能会提高，但对健康其他组成部分的影响可能是多样且出乎意料的。
