Terlingua Creek Cat’s-eye has evolved adaptations that allow it to survive in an area nearly devoid of vegetation. Photo Courtesy of William Greenwood.

Population Biology, Habitat Description and Delineation of Terlingua Creek Cat’s-eye

Terlingua Creek Cat’s-eye (Cryptantha crassipes) is an endangered plant species located solely within the drainage of Terlingua Creek and it’s tributaries in Brewster Country, Texas. All known records of Terlingua Creek Cat’s-eye are within a rock unit called the Fizzle Flat lentil. This rock unit has high occurrences of gypsum and barite, and is referred to by locals as a “moonscape”. The extremely limited range of Terlingua Creek Cat’s-eye makes it vulnerable to habitat loss or degradation, and also makes recovery difficult.

Terlingua Creek Cat’s-eye has two distinct flower types. This characteristic usually requires that the species receive pollen from the opposite flower type in order for fertilization to occur. Photo courtesy of John Wells of The Field Lab.

Borderlands Research Institute undertook a study, partnering with the Texas Parks and Wildlife Department, U.S. Fish and Wildlife Service, and private landowners, with the goal of collecting much needed information for the formulation of a recovery plan for Terlingua Creek Cat’s-eye. Protecting and assessing Terlingua Creek Cat’s-eye habitat will not only benefit that plant, but also the interesting vegetation community of the area and other rare plants with which it may have evolved.

Our research confirmed that Terlingua Creek Cat’s-eye grows in areas with a higher percentage of gypsum than in the adjacent soil area. Though it is not completely understood how Terlingua Creek Cat’s-eye evolved with adaptations that allow it to survive in areas nearly devoid of vegetation, there is evidence that the surrounding soil characteristics may have coevolved with this species providing the biological niche that it now inhabits. Through analysis of herbivory patterns and studying the chemistry of the plant, we found that Terlingua Creek Cat’s-eye has poisonous compounds in it’s leaves and roots that make it not only unpalatable, but deadly if eaten by mammals, which may have given the plant some protection against herbivory.

Terlingua Creek Cat’s-eye is only known to occur on privately owned land in southern Brewster County. Though landowners are not required by law to comply with recommendations or measures outlined in the endangered species recovery plan, they have been an important part of the effort to protect Terlingua Creek Cat’s-eye. Private property owners have collaborated to allow an assessment of previously unmapped or unknown populations, they have built fences to protect the species from off-road vehicles, and they have become citizen scientists, helping to increase the level of awareness about the species. This landowner commitment has increased the chances of recovery for this rare and unique plant.