I started out in college as an entomology major. I spent one summer in the Smoky Mtns collecting spiders for a parkwide spider inventory. I caught thousands of spiders that summer. One of these spiders was an endangered species related to tarantulas (Spruce-fir moss spider). This little guy only lives under moss that grows under Fraser firs. An invasive aphid has come in and decimated the Fraser fir population in the park, which dried out the moss under it and killed off the spider.
So there we were at the top of Mt. Le Conte. It has a big cliff at the top that people climb up to and look out. Under the edge of the cliff are a few ledges and on those ledges grow some moss. So I climbed down onto that ledge and collected a sample of the leaf litter and moss to take back to my lab.
I discovered a new population of that spider that day in a habitat that is not dependent on Fraser fir. It makes me hapy to think that now, 30 years later, those little guys are probably still hanging out under that cliff. Safe.