Protection & Restoration

It is easy to say a cave is a bat cave if it has a lot of bats. Good bat caves offer two important things for bats, 1) SAFETY from flooding, predators, and disturbance, and 2) TEMPERATURE AND HUMIDITY that is approprifate for the species and season. Some species prefer cooler roosts, some drier, and some are generalists and can use a wider variety of microclimatic conditions. We can tell if a roost is abandoned or just unsuitable by looking at the size and complexity of the cave, seasonal airflow throughout, and its physical cold air trapping or warm air trapping capabilities. We also look for forensic evidence of past bat colonies, such as old guano (sometimes buried under modern mud) and staining left on ceilings and walls from the body oils of roosting bats.

Protecting Cave Roosts

It is vitally important to protect the caves in which bats are currently found as well as those that were once used but are no longer. Sometimes this is all that is needed for bats to begin recolonizing a formerly-abandoned site. This protection can be as simple as not entering the cave when the bats are using it. For most hibernacula, this begins when bats start swarming at the entrance in mid-August, until the last bats leave hibernation at the end of April. The dates will vary somewhat depending on latitude, but should always include the fall swarming season and not wait until hibernation begins. For little-visited and technical caves, a voluntary moratorium may be all that is necessary. However, in heavily-visited caves and caves in urban areas, simple "keep out"-type signs usually don't work. Fencing the entrance perimeter may be a viable option for some sites, but fences are easily breeched and also call unnecessary attention to the cave itself.

Angle-iron cave gates are far more secure and have little effect on the flow of air, water, nutrients, and small animals in and out of the cave system if properly designed and located. BCI's Bats and Mines technical publication and the latest handbook on bat gates have plans and advice on proper gating.

It is also important to remember that protecting just the entrance to the cave doesn't protect the entire cave. Surface activities such as farming, logging, mining, and urban development can have severe impacts on the cave ecosystem, including bats. This can occur anywhere within the watershed of the cave, but especially directly over the passages themselves.

Restoring Former Roosts

The best protection efforts in the world will not make a site suitable for bats if physical changes have also occurred in the cave, altering airflow and the resultant temperatures and humidities. Caves change naturally, with entrances opening and closing, passages collapsing, and streams depositing silt and other debris. But humans also change caves by creating new entrances, enlarging passages, removing fill, and eliminating restrictions. In many cases, it is possible to identify prior conditions and restore them through additional changes to the cave or entrance. We have been developing restoration techniques at several Kentucky caves and Texas free tail caves with excellent results.

Current BCI Cave Projects:

- Indiana myotis microclimate monitoring (Eastern US)

- Gray myotis hibernacula census and Endangered Species re-evaluation (Southeastern US)

- Cave myotis roost assessment and evaluation of population status (Texas)

- Migratory bat roost identification and protection (Texas and northern Mexico)

- Protection, including gating, of critical roost sites (throughout US)

- Training of cavers in roost identification and assessment.

- Hibernacula microclimate restoration (eastern US)

For information on bats and caves, contact caves@batcon.org