Big Bend National Park in Texas is home to the only remaining Guadalupe fescue in the United States. The grass is tucked away in the Chisos Mountains, high above the Chihuahuan Desert. These mountaintops form a string of relatively wet, cool oases called "sky islands" — unique, isolated habitats. But as the planet warms, species that depend on "sky island" habitats tend to get pushed even higher up the mountain — until they eventually run out. Carolyn Whiting, Park Botanist at Big Bend, talks to host Aaron Scott about why the little things are worth preserving. Check out all the other episodes in our series on the research happening in U.S. public lands.We're on Twitter now! Tweet us @NPRShortWave. We also happily accept emails at shortwave@npr.org.