Costa Rica sits in the middle of a land bridge between North and South America, but for millions of years it was submerged, with the continents separated by ocean. Unique species evolved isolated and independent in either hemisphere. Through volcanic activity, tectonic uplifting, and glacial growth at the poles, Central America rose from the oceans, and animals flowed across the land bridge from either direction, in an event known as the Great American Biotic Exchange. Many species were initially wiped out during this period, unable to compete with the newcomers for which they had not adapted defenses. But ultimately this influx of life from two continents left Costa Rica with an extremely wide-ranging biodiversity. Adding to wide range of species, Costa Rica also sits within a climatic transition zone, between the southwestern deserts of North America and the equatorial rainforest.
In many other ecosystems throughout the world, the arrival of humans brought with them many new invasive species that devastated native food chains. Within Costa Rica however, due to its deep biodiversity, complex food webs, and previous exposure to so many species from North and South America, this hasn't been much of an issue as in other regions. Ecologically, it is far less fragile than island ecosystems, such as New Zealand or Hawaii, which have been cut off from new competition for so long. The intense competition of the jungle made it hard for new species to gain a foothold.
Yet, as with other corners of the earth, the arrival of humans has nonetheless tilted the ecological balance. Habitat loss and hunting pushed many species to the brink. Since the introduction of slash and burn agriculture, the northern pacific Guantecaste region has become more arid, with declining forests less able to absorb the suns heat and disperse water vapor.
Environmental decline was a pattern that lasted into the 70s, when the environmental movement began here. A new ethic of sustainability began to take hold across the country, valuing the protection of natural resources for future generations. Today 1/3 of the country is preserved within national parks. Anti-poaching laws are strictly enforced, where a mandatory prison sentence recently passed for those targeting protected species. Costa Rica was become the world’s first country to become carbon neutral, absorbing more greenhouse gases than what it emits. Rather than being a constraint on growth, its emphasis on environmental sustainability has become a boon for tourism, now comprising 20% of the country's economy, many of which are drawn here by the rich natural environment. Local communities have shifted to catering for adventure and eco-tourism, such as wildlife tours, ziplining, white water rafting, catch and release fishing, animal rescue sanctuaries, and permaculture farm tours. This focus on eco-tourism has made Costa Rica one of the most assessable countries within Latin America for international travelers, and today has becoming one of the world’s top ecological hotspots for wildlife viewing.