TERRESTRIAL Ecology Services

Karst, Caves, and Underground Voids

Our investigations include documentation of surface and subsurface features and the presence of subterranean organisms.  We have experience with caves, sinks and other karst features from Missouri to New Jersey to Alabama and have extensive experience working with man-made voids in the “coal fields” of Pennsylvania, Kentucky, Virginia, and West Virginia. The documentation associated with these features is important because large ground disturbances can affect the quality of ground water and other parameters of the underground habitat, and because subsidence, or the potential for it, of underground voids can require specific project design and engineering considerations.   Due to the scope and scale of linear corridor projects, pipelines, electric transmission lines, and roads are most likely to encounter concerns for protected, underground ecological features. 

There are a variety of studies that may be requested by state and federal agencies related to caves, karst features, and underground voids.  Some are related to finding and cataloguing the features while others are related to ecological issues such as the presence of woodrats, cave fish, amphibians (typically salamanders), and insects or other invertebrates.  Searches are typically made in areas where limestone is at or near the surface to locate cave entrances, sinks, swallow holes, sinking streams and karst valleys, springs, and old exposed cave systems that are the tell-tale signs of natural underground voids. 

The most commonly required studies involve surveys to determine presence or probable absence of endangered bats that might be utilizing the underground features for hibernation in winter or roosting during summer (depending on the part of the country and the endemic species).  Preliminary studies are typically conducted to assess the quality of the habitat; if the habitat is deemed “potentially suitable” then surveys are usually required to determine whether bats are actually using the feature.  There are a variety of survey methods we use, including ultrasonic sound (bat) detectors, night vision scopes, harp traps, or nets, at cave (and mine) entrances to determine whether bats are present. Some studies require a more complex approach, involving field and laboratory experimentation. For example, one study assessed the effects of noise and substrate-borne vibrations on hibernating bats.

We have extensive field experience with use of coal (and hard rock) mine portals by bats.  We maximize the return of our Clients on their consulting dollar by using GIS to target areas with past and present mining activities, coal seams, and suitable geology, and topography, maximizing the effectiveness of our field portal searches.  In the field we look for evidence of past mining, such as known and exposed coal seams, high walls, benches, areas of auger activity, spoil piles, and potential old openings used to either enter or exit the mine or move air through the mine.  Our field searches are conducted by USFWS-approved bat biologists so that when portals are located, they can be immediately assessed for their potential to provide bat habitat, negating the need for an additional return trip to the field.  Less than 25 percent of all mine voids located possess characteristics deemed appropriate for bat habitation; however, if suitable, the entrance must be sampled for bats.

In recent years there has been an increase in the frequency of use of ultrasonic sound detectors (AnaBat) to survey for bats.  This is becoming a preferred survey method by agencies because bats do not need to be handled, and avoiding handling may help prevent the spread of a disease known as white-nose syndrome (WNS).  The AnaBat records bat calls as they enter/exit the cave or portal and as they forage at night. The recordings are analyzed in the office to identify the species present and the level of activity.

Our cave and mine portal bat survey experience includes:

• Thirty years of endangered Indiana bat hibernacula surveys in Indiana.
• Fifteen years of winter surveys of the largest bat hibernacula in Ohio, located in a hard rock mine.
• Winter surveys of potential Indiana bat hibernacula in Hoosier National Forest.
• Winter surveys of potential Indiana bat hibernacula along the proposed Interstate 69 corridor in Indiana.
• A survey of hibernacula caves and temperature monitoring of those hibernacula in Virginia.
• More than 10 years of abandoned mine portal surveys for the Pennsylvania Department of Environmental Protection.
• Numerous mine portal surveys for endangered Indiana, gray, and Virginia big-eared bats in Virginia, West Virginia and Kentucky.

Click on this link to view specific project experience: KARST, CAVES AND UNDERGROUND VOIDS