About this Collection

Fifteen species of karst invertebrates are listed as endangered in central Texas. The following documents and links are provided to help you understand the life history and federal listing status of these species.

If you need to reach the Terrestrial Karst Invertebrate Biologist, contact Nicholas Gladstone.

This library collection includes information pertaining to the listed terrestrial karst invertebrates in central Texas.  The information is organized into four sections: Species, Maps and Data, Recovery, and Permitting.

  1. Species – includes links to our karst invertebrate taxonomy document and each individual species page.
  2. Maps and Data – includes links to studies on karst zones and karst fauna regions as well as information on designated critical habitat.
  3. Recovery – includes links to recovery plans as well as other documents detailing karst invertebrate habitat and recommendations for preserve design as well as management and monitoring.
  4. Permitting – includes links to Section 10(a)(1)(a) or scientific permit information.


There are fifteen species of karst invertebrates listed as endangered in central Texas: six insects (three ground beetles and three mold beetles) and ten arachnids (three harvestmen, six spiders [one delisted], and one pseudoscorpion).  These species are all generally pale with small or absent eyes and troglobitic, meaning that they are adapted to and only live underground.  A list of the scientific and common names of these species as well as links to more information about each species is provided below.  In addition, more information regarding each species' taxonomy, methods for specimen collection, and a list of taxonomists qualified to identify these species is provided in our Endangered Karst Invertebrate Taxonomy document.


Maps and Data

(This section is currently under construction)

Each of the listed species above have adapted to exclusively live underground. Karst invertebrates do not exclusively inhabit caves, but also dwell in other subterranean voids, including solution cavities, sinkholes, fractures, and mesocavernous spaces that form via the dissolution of karst landscapes. Currently these species are only known from certain karst-associated areas of Bexar, Travis, and Williamson Counties.  

Several studies have been conducted to define the areas of central Texas within which the listed species may be found. Supported by these studies, the Service has implemented the use of Karst Fauna Regions and Karst Zones. An overview document defining both concepts along with guidelines for their use and implementation is linked below.

Karst Zones and Karst Fauna Regions Overview

San Antonio Area Karst Zones and Karst Fauna Regions

The Service has developed a mapping application that includes the most up-to-date version of the San Antonio Area Karst Zones and Karst Fauna Regions, along with the designated critical habitat for each of the eight species listed in Bexar County. Additional information on the Kart Fauna Regions concept can be found at the link above and within the Bexar County Karst Invertebrates Recovery Plan in the Recovery section below.

San Antonio Area Web Map

Karst Zone and Karst Fauna Region Publication: Veni G, Cooper J, Dickerson W. 2024. Statistical Analysis and Revision of Endangered Karst Invertebrate Species Distirbution. Texas Department of Transportation (TxDOT) Voluntary Conservation Measure for US 281 from Loop 1604 to the Comal County Line, Bexar County, Texas. 74 pp (link to pdf report).

Critical Habitat: The U.S. Fish and Wildlife Service provides final critical habitat designation information for threatened and endangered species across the United States using an online mapper and by providing data that can be downloaded for use in a Geographic Information System (GIS). Critical Habitat data for the eight federally endangered karst invertebrate species in Bexar County is included in the web map linked above. You can also find both the mapper and the data on the Critical Habitat Report web page. For individual species data, scroll down the Critical Habitat Report page and enter the species into the search box.

Austin Area Karst Zones and Karst Fauna Regions - Coming Soon!

Disclaimer: Use of this data is for planning purposes only and is not a substitute for site specific geological or biological survey data. Although these data and information have been processed successfully on a computer system at the USFWS, no warranty expressed or implied is made regarding the accuracy or utility of the data and information on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data, and information, and aggregate use with other data and information. It is also strongly recommended that careful attention be paid to the contents of the metadata file associated with these data and information. The USFWS shall not be held liable for improper or incorrect use of the data and information described and/or contained herein. If you have any questions about how to interpret this data or appropriate uses, please contact our office at 512-937-7371.


Within caves and mesocaverns, or humanly impassable voids, karst invertebrates depend on high humidity; stable temperatures; suitable substrates, such as spaces between and underneath rocks; and nutrients, such as leaf litter, animal droppings, and animal carcasses.  Although they live underground, these species are dependent on the quality and quantity of water and nutrients provided from habitats on the surface.  They are endangered due to habitat destruction, degradation and fragmentation mainly resulting from urban development. Their karst habitats and the ecosystems on which they depend, have evolved slowly over millions of years and cannot be recreated once they have been destroyed. We are working with private landowners and local, city, and county governments to identify, preserve, and manage these areas.

Recovery plans - To help identify and guide species recovery needs, section 4(f) of the Endangered Species Act of 1973, as amended, directs the Service to develop and implement recovery plans for listed species or populations.  Recovery plans are advisory documents developed to provide recovery recommendations aimed at resolving the threats to the species and ensuring self-sustaining populations in the wild.  There are two recovery plans that apply to the central Texas listed karst invertebrates.

Bexar County Karst Invertebrates Recovery Plan

Recovery Plan for Endangered Karst Invertebrates in Travis and Williamson Counties, Texas

Reference is made throughout the Bexar County Karst Invertebrates Recovery Plan for where more detailed information can be found. Information on karst invertebrate habitat and ecology, karst preserve design, karst preserve management, taxonomy, and distribution can be found in the documents below.  Information in these documents may be updated periodically, so please check this website for the most recent updates.


USFWS Section 10(a)(1)(A) Scientific Permit Requirements for Conducting Presence/Absence Surveys for Endangered Karst Invertebrates in Central Texas - This document outlines the process for conducting presence/absence surveys for federally-listed endangered terrestrial karst invertebrates species in central Texas under a section 10(a)(1)(A) permit issued by the U.S. Fish and Wildlife Service under the Endangered Species Act of 1973, as amended.

Section10(a)(1)(A) permits, also referred to as recovery, enhancement of survival, or scientific permits, allow for 'take' of listed species that may or will occur while conducting research to further the recovery of a listed species. This document outlines methods to be used, information to be included in final reports, and minimum qualifications for personnel conducting presence/absence surveys for endangered karst invertebrates under a section 10(a)(1)(A) permit.

The objective of this document is to identify survey methods that will produce sound scientific information upon which to base decisions and actions for the conservation of these endangered species. Using consistent survey methodology will also allow for greater comparison and analysis of results, and thereby increase our understanding of these species and their habitat requirements. Information that relates to the effectiveness of these survey guidelines in conserving endangered karst species is welcome.

List of individuals or companies that have a valid permit to survey for endangered karst invertebrates

To apply for a scientific research and recovery permit to conduct presence/absence surveys or do research on endangered or threatened species, you will need to fill out Form 3-200-59. This form and instructions for filling it out can be found on our ePermits website.

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