Geography is Destiny

If you’ve been around the ecological world you’ve probably heard the title of this presentation many times, I mean, the first thing you

ever learn about when you take AP environmental science or your first Environment and Society-type class in college is the concept of biomes and how they are defined. On the most basic scale, local precipitation and temperature are what defines each biome. Tropical rainforest? High in precipitation, high in temperature. Tropical Savannah? Medium in precipitation, High in temperature. Desert? High in temperature and very low in precipitation. This is a gross under explanation, but I’m not going to fill this blog with details about seasonality and coastal effects that add nuance to this basic design. This local climate pattern informs what plants grow in a region, and as a result, what animals and fungi and microbes grow as well. This has been a key focus of mine throughout my stay in La Selva and now Tortuguero. The second I stepped off the plane into Costa Rica, it was very easy to feel the difference in overall climate when compared to Indiana. It certainly gets humid in Indiana, but not to this kind of oppressing level. I was covered in

sweat even before I got to the biological station. And I have remained covered in sweat until now at Tortuguero. Costa Rica is exceedingly mountainous, and the different environments caused by shifts in elevation and proximity to the ocean are very profound. Where I would be covered in a sheen of sweat sitting outside La Selva, I am relatively comfortable even without a fan writing this blog at Tortuguero. This area is not a lowland rainforest like La Selva. I am honestly not sure what type of rainforest it is exactly, but its proximity to the ocean and probable higher altitude has meant that I feel more comfortable here than I have in La Selva or anywhere close to there.

 

 

With this increased attention to climate, I also noticed a lot of things while conducting research at La Selva. The various microclimates formed by types of vegetation or geographical features were so numerous that the landscape felt more like a patchwork of microclimates than one big feature. At each pitfall trap Faith and I had set, there was a different local environment. The arboretum was open and sunny, the ant activity very evident on the ground, as they could be clearly seen exploring for fallen insects or fruits to take

back to their nests. The secondary and old growth areas were far different, however. The ants only appeared when connected to colonies, army, bullet, and leafcutter ants were evident along the trails, but the more independent black ants were far less common, it seemed. One tree we set a trap under had these massive, hard green leaves that seemed to dominate the ground. They were not the same consistency as other leaves, and appeared to decompose less quickly or at least somehow otherwise dominate the other litter. The patchwork exceeded just from visible changes. The patchworks of smell in the forests were also diverse. They ranged from sweet, to sickly sweet, to smelling of rot or feces or chemical. All things that I believe originated from the plant life, which originates, of course, from the climate. And while these different smells certainly got on my nerves (Just talk to Faith about how much I complained about my overly sensitive nose), they serve important purposes in how that particular plant functions. Smells that are uncomfortable to us may be absolutely amazing for insect pollinators like flies or wasps, or may be specifically suited to ward off those same insects from laying their eggs or eating the vegetation. We certainly found different levels of biodiversity at each site we put the traps, so we know La Selva was not a homogenous ecosystem and that something has an effect about where things live. My

hunch is that it was the vegetation, though I cannot prove that without a full blown investigation, since top down (Animal based) trophic control is a very real thing in many ecosystems.

Here at Tortuguero, along the river, I have seen new plants that create their own microclimates. The floating vegetation, very common, creates little pockets of biodiversity with their own ecosystems. Insects can thrive here, I even saw grasshoppers probably feeding on the exposed leaves. But birds like the Jacana used these areas to pluck insects out of the vegetation, while staying afloat with its absurdly long toes, appearing to walk on the water. Herons used the floating vegetation to launch attacks on fish, attracted by pieces of food tossed into the water by the birds. These small rafts form the basis of whole

ecosystems, molded by whatever climatic resources there are available. It puts into perspective how important it is to consider climate change and its impacts on local as well as global climate. Maybe rainforests as a whole will continue to exist, but what of the small climates within them? What if it gets just a bit too hot for the Cecropia tree to thrive where it normally does? Will the Azteca ants that live in its hollow shoots also die off if it does? Will the howler monkeys survive their favorite food supply getting erased from the planet? What happens when I start to sweat in Tortuguero? Will the increased humidity and heat that caused me to do so also expose plants to new fungi and bacterial parasites? The complicated web created by this limiting, but so productive, climate is fragile for each species that relies on another for its survival. And continuing to tweak the global thermometer may have some terrifying consequences down the line.