Before the 2016 MG Tour of Costa Rica started, my husband and I spent a few days at La Selva Biological Station, located in the Caribbean lowlands of northern Costa Rica. This world-famous tropical private reserve and research station is owned and operated by the Organization for Tropical Studies (OTS), a consortium of universities and research institutions from the United States, Costa Rica, and Puerto Rico.
La Selva has state-of-the-art laboratory facilities and an extensive trail system of more than 30 miles that provides access to a wide range of terrestrial and aquatic habitats. Research at La Selva is equally diverse, ranging from systematic biology and evolutionary biology to interactions among interdependent species, carbon sequestration in forests, effects of climate change on ecosystems, mechanisms of speciation, food web dynamics, maintenance of biodiversity, soil science, forestry trials of native tree species, endangered species, and much more. Over 240 scientific papers are published annually from research conducted at the site.
With dormitory rooms, cabins, a central dining hall, a workshop, and many support services, La Selva can accommodate both researchers and a limited number of guests. It mission is to protect the intact forest, provide opportunities for tropical research, and serve as an ecotourism destination and environmental education center.
Situated at the confluence of two major rivers (Sarapiquí and Puerto Viejo) in the province of Heredia, the station covers 3,900 acres of forests and disturbed lands, and is bordered on the south by Braulio Carrillo National Park, which contains more than 113,670 acres of forest land. Both are part of the 350,000+ acre Cordillera Volcánica Central Biosphere Reserve. More than half of the preserve is primary tropical rain forest, with the remainder being abandoned pastures, selectively logged secondary forest, or old plantations that are being allowed to revert back to forest.
This area is tropical and premontane wet forest, averaging over 13 feet of rainfall that is spread rather evenly throughout the year (and although the “dry” season – or maybe the least rainy season – is from February to April, it poured the entire first night we were there and our hike the second afternoon was cut short at 4pm by a downpour). There are more than 5,000 species of vascular plants, including more than 700 trees, on the station. More than 400 species of resident and migratory birds have been sighted in the reserve, and a great diversity of other animals are found here. It’s estimated that about 300,000 of the 500,000 invertebrate species found here are insects – yet we were not bothered much by mosquitoes.
The forest here has impressive trees, lianas, lots of epiphytes, a diversity of palms, and many other interesting plants. We took a long hike every morning and every afternoon on different trails, looking at whatever we encountered. Many trees have the flat, appressed juvenile leaves of climbing aroids on their lower trunks. These “shingle leaves” are produced by many types of tropical vines, especially in the genus Monstera, a group of about 50 species native to tropical America. In this growth form, the leaves have very short petioles so the blades are held flat against the tree (but derive no nourishment from it). As the plant climbs upward, the overlapping leaves look like shingles on a roof. Once they have reached a certain height (likely determined by the amount of light), the mature leaves are produced, that look like “philodendron” leaves of various sorts.
Up in the trees, a mind-boggling assortment of epiphytes cling to the limbs and trunks. Bromeliads are prominent, but there are many ferns that live this way, too, as well as many types of orchids, and even a couple of types of cactus – and sometimes all of those types could be seen on a single branch!
With so many species of trees, there was no way we could identify many of them – especially those that towered 50 or more feet over our heads where we could barely see the leaves! But some abundant species that ARE easy to pick out include Pentaclethra macroloba, a leguminous tree with attractive twice-compound leaves and large, woody seed pods; Welfia regia, a subcanopy palm that has dark red new leaves and very long fronds; and Socratea exorrhiza, the walking palm, with distinctive stilt roots (that often become covered with lichen, moss and other green things). About three quarters of the subcanopy is palms.
While looking at the vegetation, you can’t help but notice the animals in the trees and on the ground. Collared peccaries (the same species that is called javalina in the Southwestern US) are quite common and we encountered them around the buildings and out in the forest. We stopped to watch a trio of the pig-like animals chomping loudly on some palm fruits – it sounded like a big dog cracking bones. There was a bedraggled sloth curled up high in a tree, its wet fur looking like a pile of dead leaves, and we watched a female spider monkey foraging way overhead, as her baby frolicked nearby. We could hear howler monkeys off in the distance frequently, but only saw one – a very unique one, and up close, as it walked onto the cables of the suspension bridge over the river. This 3 year old male had a yellow tail and back feet where all the pigment was missing.
Butterflies of various sorts, tiny strawberry poison dart frogs galore (listen to their buzzing, insect-like call at https://en.wikipedia.org/wiki/File:Oophaga_pumilio_call.ogg), trails of leaf cutter ants, lizards, and a golden eyelash viper were some of the many smaller animals we encountered.
But the highlight for me was getting to see Honduran white bats (Ectophylla alba). These are relatively unique in two respects: they have white fur (although they look green when sunlight filters through the leaf they are roosting under) and they make their own tent by cutting the side veins of a large heliconia leaf so that the blades droop on either side of the midvein. The little white fruit-eating bats (only 1-2 inches long) cling to the inner side of the leaf upside down in small colonies of one male and several females.
Some of the many beautiful birds we saw included great currasow (including a pair that walked by our cabin one afternoon), pale-billed woodpecker, crested guan, crimson-fronted parakeet, chestnut-mandibled toucan, keel-billed toucan, collared aricari, a couple of different trogons (slaty-tailed and probably black-throated), an all-red summer tanager and broad-billed motmot. Seven endangered green macaws flew over late one afternoon, announcing their coming with loud screeches. I discovered a hummingbird nest with two featherless babies in it, hanging from the underside of a heliconia leaf near our cabin. Several Passerini’s tanagers even joined us at lunch one day!