Data for: Combining stable isotopes, trace elements, and distribution models to assess the geographic origins of migratory bats

The expansion of industrial-scale wind-energy facilities has increased the production of low-carbon emission energy but has also resulted in mortality of wildlife, including migratory bats. Management decisions can be limited by a lack of understanding of the geographic impact of bats killed at wind-energy facilities. Several studies have leveraged stable hydrogen isotope ratios (δ2H) of bat fur to illuminate this issue but are limited in the precision of conclusion because δ2H values vary primarily across latitudinal and elevational bands. One approach to increase the precision of geographic assignment is to combine independent inferences about spatial location from additional biomarkers and other related information. To test this possibility, we assigned known-origin individuals of three bat species commonly killed at on-shore wind-energy facilities in North America (Lasiurus borealis, L. cinereus, and Lasionycteris noctivagans) to probable origin using δ2H values, trace element concentrations, and species distribution models. We used cross-validation calibrated combined model tuning to determine the degree to which assignment probabilities improved when combining datasets. We found that combining markers typically performed better than single approaches. For L. borealis and L. cinereus, combining all three data sources outperformed any single or other combined approach. With an accuracy set at 80%, an average of 39.7% and 36.0% of each species’ total geographic range was considered a potential origin, respectively; stable hydrogen alone included 51.8% and 50.6% of the total geographic area.  In contrast, for L. noctivagans, including trace elements did not increase precision, and adding distribution data to δ2H values only improved precision by 0.6%. Thus, we found that a combination of multiple biomarkers typically, but not always, outperforms single marker approaches, and optimized combinations of different markers outperform equal weighting of each marker. From a practical perspective, δ2H values performed better than trace elements alone; in cases where cost is a limiting factor, the stable hydrogen should be the single biomarker used in conjunction with species distribution models. Overall, these results highlight the importance of validating methods for each species they are applied to and show that combining information from intrinsic biomarker approaches is a useful tool to document bat movements.

工业规模风力发电设施的扩张，在提升低碳能源产量的同时，也造成了包括迁徙蝙蝠在内的野生动物死亡。由于对风力发电设施致死蝙蝠的地理影响认知不足，相关管理决策常受限于此。已有多项研究借助蝙蝠毛发的稳定氢同位素比值（δ2H）解析该问题，但结论精度受限——δ2H值主要随纬度和海拔梯度发生变化。提升地理溯源精度的一种可行方案，是整合额外生物标志物及其他相关信息所得到的独立空间位置推断结果。为验证该思路，我们针对北美陆上风力发电设施常见致死的3种蝙蝠（东部红蝙蝠（Lasiurus borealis）、灰蓬毛蝠（Lasiurus cinereus）以及银毛蝠（Lasionycteris noctivagans））的已知起源个体，分别利用稳定氢同位素比值、痕量元素浓度及物种分布模型（species distribution models）推断其可能起源地。我们采用经交叉验证校准的组合模型调优方法，探究整合多数据集时溯源概率的提升程度。研究发现，整合多类标志物的溯源效果通常优于单一方法。对于东部红蝙蝠和灰蓬毛蝠，同时使用三类数据源的溯源效果优于任何单一或其他组合方式。当准确率设定为80%时，二者的潜在起源地理范围分别占其总分布区的39.7%和36.0%；而仅使用稳定氢同位素时，该占比分别为51.8%和50.6%。与之形成对比的是，银毛蝠的溯源精度未因加入痕量元素数据得到提升，仅在稳定氢同位素数据基础上补充分布数据时，精度仅提升0.6%。综上，我们发现多生物标志物的组合通常（但并非总是）优于单一标志物方法，且经优化的标志物组合效果优于对各标志物进行等权重加权的方案。从实践层面来看，稳定氢同位素的溯源效果优于单一痕量元素检测；若受成本因素限制，可单独采用稳定氢同位素检测，并结合物种分布模型开展溯源工作。总体而言，本研究结果凸显了针对每一类应用物种验证方法的重要性，并证实整合内源性生物标志物的相关信息，是记录蝙蝠移动路径的有效工具。