Geographic source of bats killed at wind-energy facilities in the eastern United States.

Bats subject to high rates of fatalities at wind-energy facilities are of high conservation concern due to the long-term, cumulative effects they have, but the impact on broader bat populations can be difficult to assess. One reason is the poor understanding of the geographic source of individual fatalities and whether they constitute migrants or more local individuals. Here, we used stable hydrogen isotopes, trace elements and species distribution models to determine the most likely summer geographic origins of three different bat species (Lasiurus borealis, L. cinereus, and Lasionycteris noctivagans) killed at wind-energy facilities in Ohio and Maryland in the eastern United States. In Ohio, 41.6%, 21.3%, 2.2% of all individuals of L. borealis, L. cinereus, and L. noctivagans, respectively, had evidence of movement. In contrast, in Maryland 77.3%, 37.1%, and 27.3% of these same species were classified as migrants. Our results suggest bats killed at a given wind facility are likely derived from migratory as well as resident populations. Finally, there is variation in the proportion of migrants killed between seasons for some species and evidence of philopatry to summer roosts. Overall, these results indicate that the impact of wind-energy facilities on bat populations occurs across a large geographic extent, with the proportion of migrants impacted likely to vary across species and sites. Similar studies should be conducted across a broader geographic scale to understand the impacts on bat populations from wind-energy facilities.

White-Nose Syndrome Pathogen Pseudogymnoascus destructans Detected in Migratory Tree-Roosting Bats.

White-nose syndrome (WNS) is an emerging fungal epizootic disease that has caused large-scale mortality in several species of North American bats. The fungus that causes WNS, Pseudogymnoascus destructans (Pd), has also been detected in bat species without diagnostic signs of WNS. Although these species could play a role in WNS spread, understanding of the spatial and temporal extents of Pd occurrence on WNS-resistant species is limited. This study evaluated the presence of Pd on 272 individuals of three species of migratory tree-roosting bats: hoary (Lasiurus cinereus), eastern red (Lasiurus borealis), and silver-haired (Lasionycteris noctivagans) bats, obtained opportunistically during summer and autumn from throughout much of their ranges in North America. We also compared tissue sampling protocols (i.e., tissue swabbing, fur swabbing, and DNA extraction of excised wing tissue). We detected Pd on three eastern red bats from Illinois and Ohio, US, one silver-haired bat from West Virginia, US, and one hoary bat from New York, US, all via DNA extracted from wing tissue of carcasses. These results document the first publicly reported detections of Pd on a hoary bat and on migratory bats during the autumn migratory period, and demonstrate the potential for using carcasses salvaged at wind-energy facilities to monitor for Pd.

Analysis of biodiversity data suggests that mammal species are hidden in predictable places.

SignificanceOnly an estimated 1 to 10% of Earth's species have been formally described. This discrepancy between the number of species with a formal taxonomic description and actual number of species (i.e., the Linnean shortfall) hampers research across the biological sciences. To explore whether the Linnean shortfall results from poor taxonomic practice or not enough taxonomic effort, we applied machine-learning techniques to build a predictive model to identify named species that are likely to contain hidden diversity. Results indicate that small-bodied species with large, climatically variable ranges are most likely to contain hidden species. These attributes generally match those identified in the taxonomic literature, indicating that the Linnean shortfall is caused by societal underinvestment in taxonomy rather than poor taxonomic practice.

Predicting migration routes for three species of migratory bats using species distribution models.

Understanding seasonal variation in the distribution and movement patterns of migratory species is essential to monitoring and conservation efforts. While there are many species of migratory bats in North America, little is known about their seasonal movements. In terms of conservation, this is important because the bat fatalities from wind energy turbines are significant and may fluctuate seasonally. Here we describe seasonally resolved distributions for the three species that are most impacted by wind farms (Lasiurus borealis (eastern red bat), L. cinereus (hoary bat) and Lasionycteris noctivagans (silver-haired bat)) and use these distributions to infer their most likely migratory pathways. To accomplish this, we collected 2,880 occurrence points from the Global Biodiversity Information Facility over five decades in North America to model species distributions on a seasonal basis and used an ensemble approach for modeling distributions. This dataset included 1,129 data points for L. borealis, 917 for L. cinereus and 834 for L. noctivagans. The results suggest that all three species exhibit variation in distributions from north to south depending on season, with each species showing potential migratory pathways during the fall migration that follow linear features. Finally, we describe proposed migratory pathways for these three species that can be used to identify stop-over sites, assess small-scale migration and highlight areas that should be prioritized for actions to reduce the effects of wind farm mortality.

Using trace elements to identify the geographic origin of migratory bats.

The expansion of the wind energy industry has had benefits in terms of increased renewable energy production but has also led to increased mortality of migratory bats due to interactions with wind turbines. A key question that could guide bat-related management activities is identifying the geographic origin of bats killed at wind-energy facilities. Generating this information requires developing new methods for identifying the geographic sources of individual bats. Here we explore the viability of assigning geographic origin using trace element analyses of fur to infer the summer molting location of eastern red bats (Lasiurus borealis). Our approach is based on the idea that the concentration of trace elements in bat fur is related through the food chain to the amount of trace elements present in the soil, which varies across large geographic scales. Specifically, we used inductively coupled plasma-mass spectrometry to determine the concentration of fourteen trace elements in fur of 126 known-origin eastern red bats to generate a basemap for assignment throughout the range of this species in eastern North America. We then compared this map to publicly available soil trace element concentrations for the U.S. and Canada, used a probabilistic framework to generate likelihood-of-origin maps for each bat, and assessed how well trace element profiles predicted the origins of these individuals. Overall, our results suggest that trace elements allow successful assignment of individual bats 80% of the time while reducing probable locations in half. Our study supports the use of trace elements to identify the geographic origin of eastern red and perhaps other migratory bats, particularly when combined with data from other biomarkers such as genetic and stable isotope data.

Sequencing whole mitochondrial genomes to assess genetic divergence between proposed silver-haired bat (Lasionycteris noctivagans) populations.

The geographic distributions of eastern and western Lasionycteris noctivagans populations suggest they could be genetically isolated, but this has rarely been assessed using genetic data. Here, we evaluate this possibility by sequencing the complete mitochondrial genome of four silver-haired bats from eastern and western populations. The three usable mitogenomes were closely associated with other Vespertilionid bats and the phylogenetic tree revealed the two western individuals grouping together to form their own clade. Our results support the idea of small but significant genetic differences between eastern and western populations of these bats, but this should be tested further.