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Ecosystems of Costa Rica
Costa Rica contains an extraordinary array of natural ecosystems especially considering the size of the country. A trek of a few miles is frequently enough to take you from one to another, each with its own unique diversity of plants and animals. The diversity of ecosystems in Costa Rica is largely due to the country’s mountains, which produce an assortment of “life zones” at varying altitudes and rainfall patterns. Many plant and animal species are unique to one zone, while some are found in several zones. Dry Tropical forest
Very little rain falls for four or five months of the year in some parts of Costa Rica, particularly the lowlands of Guanacaste Province. In this area, the indigenous vegetation is dry tropical forest, with the majority of the trees dropping their leaves soon after the dry season begins. Normally, the trees will grow no more than 100 ft. high in this region, and there is, more often than not, a tangled understory of spiny and thorny shrubs.
Few of the trees are fully dormant during the dry season and although the trees are leafless, many will flower soon after dropping their leaves. The Cortes tree (guayacan), which puts on an impressive display of waxy yellow blooms, is a particularly eye catching flowerer during the dry season. Reptiles, such as rattlesnake and a large lizard known as ctenosaurs abound in the dry tropical forest, often feeding on the fallen guayacan flowers and fruit.
Found at the highest altitudes in Costa Rica, the forest stops and gives way to a treeless terrain known as paramo. Often shrouded in clouds and cold, paramo seems light years removed from the warmth and lushness of the lower altitudes. This ecosystem is made up of durable, low-growing shrubs that can withstand the strong winds that continuously sweep through the higher altitudes. The paramos found in Costa Rica, in particular the Talamanco Mountains, are the northernmost in the Americas. Rainforest
The wet and warm climate of the Costa Rican lowlands is nearly perfect for trees to keep growing year around. This continuous growth is generally thought of as rainforest, but technically speaking, botanists usually reserve this word for the wettest forests of all. The trees in the rainforest are evergreen, unlike the trees found in the tropical dry forests of Costa Rica. The evergreens form a dense never ending canopy or ceiling, which even the rays of the sun have difficulty penetrating. In lowland rainforest, trees average approximately 165 ft. in height, but many other trees (emergents) can reach 200ft. or more above the canopy. As the altitude gets higher, the canopy height begins to drop. Since sunlight is at a premium, many other plants use the branches of the evergreens as their own personal perches. Trees are often host to epiphytic plants, such as bromeliads, orchids and ferns, and it is quite common, to see literally hundreds of such plants clingingly to their host tree. While causing the host tree no damage, these plants can grow quite large and get exceedingly heavy, especially with an abundance of rain. Subsequently, the combined weight will often bring branches crashing to the ground.
The Costa Rica rainforest is teeming with exotic wildlife as many species of animals make this habitat their home. Although home to a vast array of wildlife, animals are often difficult to actually see. With the exception of monkeys and agoutis, much of the rainforest wildlife is nocturnal. The rainforest canopy provides an excellent refuge, where a multifaceted community of species lives with little contact with the ground below. Freshwater wetlands
Costa Rican rivers are generally short and fast-flowing, swiftly completing their trek from the country’s interior to the sea. Tropical down-pours are quite common in Costa Rica and freshwater animals are practiced in the art of taking cover when water levels suddenly increase or fluctuate. River wildlife is more diverse on lower ground, where river flow is much more sluggish. In particular, caimans can often be found here basking on the banks, as well as one of the world’s few bipedal lizards, the Basilisk (also known as the Jesus lizard), which runs across the water on its back legs to escape predators.
Plant life along the rivers can be quite stunning. Although many small streams run beneath the never ending overhead canopy, sunlight rarely makes it to the banks. Rivers being larger are often broad enough to allow light to reach the forest floor, which results in a profusion of plant growth. Pollinated by hummingbirds or bats, heliconias, or lobster claws are a particularly spectacular species. They frequently grow on mudbanks and sandbars, but rarely grow deep in the rainforest.
Lake Arenal is Costa Rica’s largest body of freshwater and has an apparent highland feel and while it has an abundance of fish, like the guapote, its bird life is unremarkable. In direct contrast, Palo Verde National Park and Cano Negro, with their shallow lakes and marshes, have more prolific ecosystems. These seasonal wetlands are home to a vast array of birds, especially when water levels are low, and prey is more plentiful and easy to catch.
Mangroves are described as an evergreen tree or bush with straight slender stems and intertwined roots that are exposed during low tide and they’re the natural vegetation of muddy, low-lying coasts throughout the tropics. There are five species of mangrove found in Costa Rica, and they form extensive networks on both the Caribbean and Pacific shores. Although these five mangrove species are quite different from each other, they have all evolved and adapted to surviving in seawater and saline slit. Their evolutionary process includes mechanisms for getting rid of excess salt and also elaborate roots that secure them in the ever-shifting mud.
Costa Rican mangrove swamps are teeming with life. Many species of bird find refuge in the mangroves as do various snakes and lizards and other animals as well. Crabs are found in abundance here such as fiddler crabs, fist-sized land crabs, and the mangrove tree crab, which leaps from branch to branch eating mangrove leaves. Even the mud in the mangrove swamps is of importance in the marine food chain, with its nutrient rich algae and other small organisms it produces. Coasts and coral reefs
Apart from mangrove swamps, Costa Rica’s approximately 750 miles of coastline consists largely of extensive beaches, low-lying rocks, and a few number of offshore islands. The two coastlines of Costa Rica are never really far apart, but their marine life is quite different as are the physical aspects of each. These physical differences not only affect marine life, but other animals as well. For instance, the Brown Pelican, which is found on both coasts, will only breed on the Pacific coast where the rocky islands protect its nesting area. The magnificent frigatebird is also sighted more often on the Pacific coast.
There are a number of coral reefs located on the Pacific side of Costa Rica, but only one significant area on the Caribbean, at Cahuita. Reef building corals can only survive in clear water as they need sunlight to grow. They need to be in an area that is far removed from the mouths of silt-ridden rivers. Recently, the Cahuita reef has been affected by deforestation, which in turn has increased silt levels.