DeBerry Douglas A, Hunter Dakota M
Environment and Sustainability Program, College of William & Mary, Williamsburg, VA 23187, USA.
Biology Department, College of William & Mary, Williamsburg, VA 23187, USA.
Biology (Basel). 2024 Apr 18;13(4):275. doi: 10.3390/biology13040275.
We sampled vegetation communities across plant invasion gradients at multiple wetland and stream mitigation sites in the Coastal Plain and Piedmont physiographic provinces of Virginia, USA. Impacts of invasion were evaluated by tracking changes in species composition and native vegetation community properties along the abundance gradients of multiple plant invaders. We found that native species richness, diversity, and floristic quality were consistently highest at moderate levels of invasion (ca. 5-10% relative abundance of invader), regardless of the identity of the invasive species or the type of mitigation (wetland or stream). Likewise, native species composition was similar between uninvaded and moderately invaded areas, and only diminished when invaders were present at higher abundance values. Currently, low thresholds for invasive species performance standards (e.g., below 5% relative abundance of invader) compel mitigation managers to use non-selective control methods such as herbicides to reduce invasive plant cover. Our results suggest that this could cause indiscriminate mortality of desirable native species at much higher levels of richness, diversity, and floristic quality than previously thought. From our data, we recommend an invasive species performance standard of 10% relative invader(s) abundance on wetland and stream mitigation sites, in combination with vigilant invasive plant mapping strategies. Based on our results, this slightly higher standard would strike a balance between proactive management and unnecessary loss of plant community functions at the hands of compulsory invasive species management.
我们在美国弗吉尼亚州沿海平原和皮埃蒙特地貌区的多个湿地和溪流缓解场地，沿着植物入侵梯度对植被群落进行了采样。通过追踪多种植物入侵者丰度梯度上物种组成和本地植被群落特性的变化，评估入侵的影响。我们发现，无论入侵物种的身份或缓解类型（湿地或溪流）如何，在中等入侵水平（入侵者相对丰度约为5-10%）时，本地物种丰富度、多样性和植物区系质量始终最高。同样，未入侵和中等入侵区域的本地物种组成相似，只有当入侵者以更高的丰度值出现时才会减少。目前，入侵物种性能标准的低阈值（例如，入侵者相对丰度低于5%）迫使缓解管理者使用除草剂等非选择性控制方法来减少入侵植物覆盖。我们的结果表明，这可能会导致比以前认为的更高水平丰富度、多样性和植物区系质量的理想本地物种被无差别杀死。根据我们的数据，我们建议在湿地和溪流缓解场地采用10%入侵者相对丰度的入侵物种性能标准，并结合警惕的入侵植物绘图策略。根据我们的结果，这个略高的标准将在积极管理和因强制性入侵物种管理而导致的植物群落功能不必要损失之间取得平衡。
