Kansas Cooperative Fish and Wildlife Research Unit, Division of Biology, Kansas State University, 205 Leasure Hall, Manhattan, KS, 66506, USA.
WRA Environmental Inc., San Rafael, CA, 94901, USA.
Ecotoxicology. 2019 Sep;28(7):809-824. doi: 10.1007/s10646-019-02079-1. Epub 2019 Jul 19.
The magnitude and distribution of lead contamination remain unknown in wetland systems. Anthropogenic deposition of lead may be contributing to negative population-level effects in waterfowl and other organisms that depend on dynamic wetland habitats, particularly if they are unable to detect and differentiate levels of environmental contamination by lead. Detection of lead and behavioral response to elevated lead levels by waterfowl is poorly understood, but necessary to characterize the risk of lead-contaminated habitats. We measured the relationship between lead contamination of wetland soils and habitat use by mottled ducks (Anas fulvigula) on the Upper Texas Coast, USA. Mottled ducks have historically experienced disproportionate negative effects from lead exposure, and exhibit a unique nonmigratory life history that increases risk of exposure when inhabiting contaminated areas. We used spatial interpolation to estimate lead in wetland soils of the Texas Chenier Plain National Wildlife Refuge Complex. Soil lead levels varied across the refuge complex (0.01-1085.51 ppm), but greater lead concentrations frequently corresponded to areas with high densities of transmittered mottled ducks. We used soil lead concentration data and MaxENT species distribution models to quantify relationships among various habitat factors and locations of mottled ducks. Use of habitats with greater lead concentration increased during years of a major disturbance. Because mottled ducks use habitats with high concentrations of lead during periods of stress, have greater risk of exposure following major disturbance to the coastal marsh system, and no innate mechanism for avoiding the threat of lead exposure, we suggest the potential presence of an ecological trap of quality habitat that warrants further quantification at a population scale for mottled ducks.
湿地系统中铅污染的程度和分布情况仍不清楚。人为的铅沉积可能会对依赖湿地动态栖息地的水禽和其他生物造成负面影响，尤其是当它们无法察觉和区分环境铅污染的水平时。水禽对铅的检测及其对高铅水平的行为反应还了解甚少，但对于描述受铅污染栖息地的风险是必要的。我们测量了美国德克萨斯州上海岸湿地土壤铅污染与斑点鸭（Anas fulvigula）栖息地利用之间的关系。斑点鸭历史上受到铅暴露的不成比例的负面影响，并且表现出独特的非迁徙生活史，当它们栖息在污染地区时，会增加暴露的风险。我们使用空间插值来估计德克萨斯州Chenier 平原国家野生动物保护区复合体的湿地土壤中的铅。土壤中的铅含量在保护区复合体中存在差异（0.01-1085.51 ppm），但更高的铅浓度通常与传布斑点鸭密度较高的区域相对应。我们使用土壤铅浓度数据和 MaxENT 物种分布模型来量化各种栖息地因素和斑点鸭位置之间的关系。在重大干扰的年份，利用具有更高铅浓度的栖息地的情况增加了。由于斑点鸭在压力时期使用含铅量高的栖息地，在沿海沼泽系统受到重大干扰后，它们暴露的风险更大，并且没有避免铅暴露威胁的内在机制，因此我们建议存在一个高质量栖息地的生态陷阱，需要在斑点鸭种群规模上进一步量化。
