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 broken apart. 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 species poured across the land bridge from either direction. Many species were initially wiped out in this exchange, 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 of species. Adding to the diversity 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 an island such as New Zealand or Hawaii, which have been cut off from new competition for so long. The intense competition of the jungle makes in 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 forests no longer able to absorb the suns heat and disperse water vapor.
Environmental decline was a pattern that lasted into the 70s, when the environmental movement took hold. 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 two year prison sentence recently passed for those targeting protected species. And Costa Rica has become the first country to be 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 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.