Bowen Anna K M, Stevens Martin H H
Department of Biology Miami University Oxford Ohio USA.
Ecol Evol. 2020 Sep 23;10(19):10785-10797. doi: 10.1002/ece3.6735. eCollection 2020 Oct.
Despite the large literature documenting the negative effects of invasive grasses, we lack an understanding of the drivers of their habitat suitability, especially for shade-tolerant species that do not respond positively to canopy disturbance. We aimed to understand the environmental niche and potential spatial distribution of a relatively new invasive species, wavyleaf basketgrass ( (Ard.) Roem. & Schult, WLBG) by leveraging data available at two different spatial scales.
Mid-Atlantic region of the United States.
Maximum entropy modeling (Maxent) was used to predict the habitat suitability of WLBG at the regional scale and the landscape scale. Following variable evaluation, model calibration, and model evaluation, final models were created using 1,000 replicates and projected to each study area.
At the regional scale, our best models show that suitability for WLBG was driven by relatively high annual mean temperatures, low temperature seasonality and monthly range, low slope, and high cumulative Normalized Difference Vegetation Index (NDVI). At the landscape scale, suitability was highest near roads and streams, far from trails, at low elevations, in sandy, moist soil, and in areas with high NDVI.
We found that invasion potential of this relatively new invader appears high in productive, mesic habitats at low slope and elevations. At the regional scale, our model predicted areas of suitable habitat far outside areas where WLBG has been reported, including large portions of Virginia and West Virginia, suggests serious potential for spread. However, large portions of this area carry a high extrapolation risk and should therefore be interpreted with caution. In contrast, at the landscape level, the suitability of WLBG is largely restricted to areas near current presence points, suggesting that the expansion risk of this species within Shenandoah National Park is somewhat limited.
尽管有大量文献记录了入侵性禾本科植物的负面影响，但我们对其栖息地适宜性的驱动因素仍缺乏了解，尤其是对于那些对林冠干扰没有积极响应的耐荫物种。我们旨在通过利用两个不同空间尺度上可得的数据，了解一种相对较新的入侵物种——波叶臂形草（(Ard.) Roem. & Schult，WLBG）的环境生态位和潜在空间分布。
美国中大西洋地区。
利用最大熵建模（Maxent）预测WLBG在区域尺度和景观尺度上的栖息地适宜性。经过变量评估、模型校准和模型评估后，使用1000次重复创建最终模型，并将其投影到每个研究区域。
在区域尺度上，我们的最佳模型表明，WLBG的适宜性受到相对较高的年平均温度、较低的温度季节性和月变化范围、低坡度以及高累积归一化植被指数（NDVI）的驱动。在景观尺度上，适宜性在道路和溪流附近最高，远离步道，在低海拔地区，在沙质、湿润的土壤以及NDVI较高的地区。
我们发现，这种相对较新的入侵者在低坡度和低海拔的高产、中生栖息地中的入侵潜力似乎很高。在区域尺度上，我们的模型预测的适宜栖息地面积远远超出了已报道WLBG存在的区域，包括弗吉尼亚州和西弗吉尼亚州的大部分地区，这表明其有严重的扩散潜力。然而，该区域的大部分存在较高的外推风险，因此应谨慎解读。相比之下，在景观层面，WLBG的适宜性在很大程度上局限于当前存在点附近的区域，这表明该物种在谢南多厄国家公园内的扩张风险在一定程度上是有限的。
