Secondary effects of White-Nose Syndrome

With the collapse of many populations of bat species due to White-Nose Syndrome (WNS), land managers and scientists are trying to figure out how to support the bat colonies and individuals that are left. To move toward restoring bat populations, it is critical to keep surviving bats healthy and connected to each other across landscapes.

The hibernating bat species found in eastern United States are short-distance migrants that move from winter hibernacula (hibernation places) to summer areas where they breed and raise their young. Small groups of surviving individuals face additional threats when they move to summer habitat such as finding suitable roosting and foraging habitats near food and water resources. This means that subpopulations of bats that are resistant to WNS may become part of scattered populations.

Scientists want to understand bats’ movement patterns and habitat needs during migration and to reduce stress on bats, especially those that have survived WNS infection and are weak.

Key Findings

• Little Brown Bats and other bat species across North America are facing devastation from White-nose Syndrome.
• Little Brown Bats are most successful at finding food when temperatures are warmer, there is little wind, and it is not raining.
• Bats forage most often in areas close to their cave entrance, especially when there are openings in vegetation that allow them to cut through the forest.
• In general, bats preferred forests with openings near the treetops, areas with roads, and places with more rugged terrain. They do not seem to favor places with water bodies like lakes and rivers.
• The genetic analysis done so far found that bats from Kentucky, Louisiana, Michigan, Minnesota, North Carolina, Oklahoma, and Wisconsin have about the same amount of genetic variability.

Research Approach

Bat Behaviors in Spring Versus Fall
The landscapes around hibernacula provide critical habitat in both the spring and fall but scientists know very little about how bats use them. In spring, bats emerge from hibernation in poor physical condition and require up to 2 weeks to recuperate. In the fall, bats converge on these same landscapes for mating before starting hibernation.

The research team is using acoustic monitoring to determine patterns of bat foraging and other activities to identify important habitat features.

Genetic Analysis
Many eastern U.S. forests provide summer habitat for bats but lack hibernacula. Managers do not know where bats are migrating to and from. Scientists are comparing genetic data from little Brown bats and northern long-eared bats to identify movement patterns between the critical habitats in their life cycle to better understand how bat populations interact regionally.

Another genetic analysis is trying to figure out what makes some bats more resistant to WNS than others. Just as in humans, the microorganisms on their skin help protect bats against disease causing organisms and may help regulate an individual’s immune system. This means that genetic variation among bats may affect the microorganisms living on their skin and, in turn, make some bats more resistant to WNS. In addition, bats that have been exposed to the fungus that causes WNS may have disease-resistance genes and more protective microbial communities.

To understand this possible link between genetics and WNS resistance in bats, scientists are comparing the genetic makeup of bats and the microorganisms on their skin in regions of the country where WNS is found with the same information from bats that live in regions where bats do not suffer from WNS.

Finally, the research team is looking at the genetic diversity of the northern long-eared bat (Myotis septentrionalis) across the United States, especially in places that White-nose syndrome has not reached. This data is helping scientists figure out how many bats are living now and how many of them can reproduce.

Outcomes

Managers can eventually use the information from this research to provide high quality habitats for bats throughout their life cycles including while they are migrating, mating, hibernating, and emerging from hibernation.

Supporting disease resistant populations of bats and providing them with high quality habitat will help disease resistant individuals spread across the landscape and reproduce.