Changing ecosystems can force plants and animals into precarious niches. These relict populations, extinct or out-competed elsewhere, survive isolated from the wider world. Sometimes their habitats are fairly large – the continent of Australia is the home for our relict marsupials (who used to be much more widespread) – but other times they’re quite small and quite extreme. The British subspecies of Snowdon lily only lives on certain near-inaccessible mountain sides in Snowdonia National Park. Even more extreme, Borderea chouardii, a small flowering herb, lives only on two vertical cliffs in the Pyrenees.
Actually, a quick aside. Besides it’s isolation, scientists this week published findings showing that Borderea also shares a double-mutualistic relationship with local ant species. The ants not only pollinate its flowers, they also serve as the major seed dispersers. These double-mutualistic relationships are very rare. And while this may appear as a weakness at first (since if anything happens to the ants Borderea would have a very difficult time reproducing) this may be offset by the plant’s extremely long (300 year!) lifespan and the fact that this isolation saves it from herbivorous predators and competition.
But perhaps the most extreme relict population comes from off the coast of Australia. Ball’s Pyramid rises out of the Pacific Ocean like some sort of island fortress, 1800 feet of sheer cliff and inhospitable rock.
In 2001, two rock-climbing scientists found huddling under a single bush the entire remaining population of Dryococelus australis, a nearly foot-long stick insect. It’s so formidable-looking, it is sometimes known as the tree-lobster. The scientists have since started a breeding program back on the Australian mainland.