Galápagos Expedition 2017: A Journey into the Unknown
June 20, 2017--
"There's so much we still don't know about this place..." --
Pedro says to me as he looks out across the vast volcanic crater of Sierra Negra. It's the second largest active caldera in the world, last erupting 15 years ago in 2005.
Pedro was a ranger of the Galápagos National Park for 12 years, a short time by Galápagos standards he says, but enough for him to have seen every island and every volcano of the archipelago. He's a veteran explorer by any standards, yet he humbly and proudly admits how little is known about these legendary islands. Indeed, there is much in the Galápagos that is still thoroughly untouched and unexplored by any scientist, ranger, or otherwise.
That's why I'm here.
As we stood on the edge of that vast crater, I was scouting for a pair of tree species. One is a gregarious insular invader, commonplace among oceanic archipelagos world-wide: Guava. You likely know it for its fruit. The other is an elusive Galápagos endemic, a white ghost hidden among the sprawling canopy of the former: Guayabillo. Both are species within the genus Psidium, family Myrtaceae. In other words, both are species of guava. The former species was introduced by humans and has since become invasive, while the latter species is to native (and only found in) Galápagos. It is here - on the rim of an active volcano - that they can both be found growing together.
I'm on the hunt for a powerful mechanism of evolution, a known driver of speciation, adaptive radiation, and invasion known as hybridization. Hybridization is the interbreeding of distinct evolutionary lineages, or species. "Species" is a contentious term among biologists, and you will be hard pressed to find an evolutionary biologist that doesn't have strong feelings about what the term means. A part of the controversy is in fact due to hybridization. After all, how can you bin critters into nice neat categories if they have the tendency to mix and mingle their identities into a seemingly incoherent mess of "A"s, "T"s, "C"s, and "G"s. It's a subject that Darwin himself pondered extensively and frequently commented on in his writings, such as Variation of Animals and Plants under Domestication (1868) in which he writes "There can be no doubt that crossing, with the aid of rigorous selection during several generations, has been a potent means in modifying old races, and in forming new ones..."
LAS ISLAS ENCANTADAS - The enchanted isles, Islands of Fire, Darwin's Eden... The Galápagos is a legendary place with many names. Being a scientist here in the Galápagos is perhaps the closest I'll ever come to feeling like a movie star. It is truly astonishing to me the weight that the name carries here, even though in reality I'm just a kid with a microscope and a craving for knowledge.
This summer has been one of the most rewarding experiences of my life. Fieldwork, as all field biologists well know, is always a whirlwind of decisions, emotions, and leaps of faith. This summer was no exception. You can plan for weeks, months, years even, but you never really know what you're getting yourself into until your already in it. Being my first field season here, this was absolutely the case for me. There were times of panic, like realizing there wasn't any way of accessing money within the tiny town on Isabela island. There were times of excitement, like examining a population of potential hybrids for the first time. There were times of absurdity, like having to go from store to store asking for spare newspaper to fill my plant press and receiving confused looks from about everyone in town..
Yet in the end, everything worked out better than I could have ever planned!