The La Selva Suspension Bridge

We first discussed corridors in relation to habitat fragmentation, with my professor explaining the various benefits and negatives of them. While they can allow animals to migrate and gene flow to persist, they can also have a larger role in the spread of diseases and increase predation risk. Often, when corridors are discussed it is in reference to natural ones - those consisting of narrow strips of forest connecting two larger areas of forest.  More modernly, some artists and engineers have been creating natural, living bridges for animals (and people) to use as corridors.  However, I don’t think these examples represent the variety of opportinites for developing and maintaining connectivity. As biologists, and specifically one interested in environmental science, I think it’s easy for me to see man-made objects or creations as having negative impacts on the environment and wildlife around me. Throughout my experience in biology, I’ve repeatedly discussed the huge, and negative impacts that humans and man made things have on the environment. And while this is true in many cases, the La Selva Biological Station could be an example of how it isn’t always true. 

            Dr. Leslie Holdridge established the La Selva Biological Station in 1954. It was originally intended to be an experimental farm, however was purchased by the Organization of Tropical Studies in 1968, becoming a private biological station and reserve. The station is situated near the conjunction of two large rivers: the Puerto Viejo and the Sarapiqui. The Puerto Viejo runs directly in front of the station, and across the northern border of the reserve. When the station was first established, visitors to the station had to boat down this river, supplies and all, in order to get access to the facilities. However, in 1982, the station built a large suspension bridge that crosses the Puerto Viejo and allows ease of access to the forest and facilities for researchers working at the station. 

            When I first arrived at La Selva, I was terrified of the bridge. Suspended high above the large, crocodile and caiman inhabited river, and about on par with the canopy of some large trees, the bridge was the epitome of my fear of heights. However, in the weeks I spent at La Selva, I became fonder of the bridge (as I crossed it around 10X a day), in part due to the animals I could see from the bridge. Walking to class in the morning, I would often see social flycatchers (Myiozetetes similis) and Montezuma oropendolas (Psarocolius montezuma), two common bird species at La Selva, gathering twigs and flying from treetop to treetop. After lunch, it was easy to spot turtles and, if we were lucky, caiman, sunning themselves on the logs and banks below. But walking back at night was always when we saw the most exciting animals.

            Not only did we often see a variety of animals from the bridge, I noticed quite a few animals using this bridge to cross the river. On one of our first nights here, I watched as a sloth slowly climbed across the bridge railing, gaining access to leaves and trees on the opposite side of the bridge before retreating into the canopy. Opossums and anteaters are some of the other larger nocturnal mammals I’ve watched use the bridge to efficiently move across the river to the forest and back. During the day, it’s not uncommon to see a family of howler monkeys moving across the bridge railings, often making loud calls and eventually moving into the deeper forest on the far side of the bridge. I’ve also noticed geckos climbing the tall metal posts along the bridge, and birds utilizing the bridge for nesting areas. In my short time here at La Selva, I’ve had quite a few interactions with animals utilizing this bridge, so one can only imagine over time what you could see. More importantly, this illustrates the potential benefits that manmade things, such as this bridge, can have for wildlife.

            When I imagine a corridor, I don’t imagine a giant suspension bridge. However, after watching all of these animals use this bridge to cross the river, presumably much faster than they would be able to without, I have a new perspective on the definition of corridor. I don’t think that corridors necessarily have to be 100% natural, or that man made objects have to be 100% bad for wildlife. Rather, I think this bridge illustrates that it’s possible to develop with humans and wildlife in mind, and to create things that can benefit both. While this may not be the intended effect of this bridge, it has proven to be useful in some aspects for organisms living here. Like this with bridge, I think it is more a matter of looking at development in a different perspective, rather than trying to prevent or limit human development, which is less realistic to me. If we can find more innovative ways to continue to develop and benefit rural areas while also benefitting the environment and wildlife, I think we can be more successful in preserving wildlife as a whole.

Natalie Myers

Oxidental College