Along with those species that have been afforded legal protection (Federal/State Listed Species) due to risk of extinction, Texas also contains well over 1,300 species that are considered to be Species of Greatest Conservation Need. These are species that, due to limited distributions and/or declining populations, face the threat of extirpation or extinction but lack legal protection.
The lists below were developed for Texas Parks and Wildlife Department's (TPWD) revised Texas Conservation Action Plan. Species are ranked using a conservation status system established by NatureServe. Each species and plant community possesses a global (range-wide) and state rank based on their respective rarity. The conservation status of a species is designated by a number from one to five, preceded by a letter reflecting the appropriate geographic scale (G=Global, S=State). Numbers have the following meaning: 1) Critically imperiled, 2) Imperiled, 3) Vulnerable, 4) Apparently secure, and 5) Secure.