A biodiversity hotspot is a biogeographic region that is both biologically rich and highly threatened with destruction from urbanization, development, pollution, and diseases. For a region to be classified as a biodiversity hotspot, it must have at least 1,500 vascular plants strictly endemic to the habitat and must have at most 30% of its original natural vegetation. Thirty-six areas in the world qualify as biodiversity hotspots. In North America and Central America, only three regions, namely the California Floristic Province, Madrean pine-oak woodlands, and Mesoamerica, qualify as biodiversity hotspots. They support nearly 60% of world’s mammal, plant, amphibian, reptile, and bird species, a majority of which are endemic to the specific hotspots. A great deal of conservation is required to preserve the remaining land of these hotspots.
3. California Floristic Province
California Floristic Province is located along the Pacific coast of North America. It boasts as the only hotspot occurring within the boundaries of the United States. It is also one of the only five areas in the world with a Mediterranean climate characterized by hot, dry summers and cool, wet winters. The hotspot is a mixture of various ecosystems including the juniper-pine woodland, prickly pear shrubland, and coastal sage scrub.
The California Floristic Province is home to 3,488 native plant species, 2,100 of which are endemic to the region. The southern Sierra Nevada ecological unit is home to the giant sequoia trees alleged to be the largest tree species in the world. Moreover, the Klamath-Siskiyou ecosystem has rare plant species with twenty of the most diverse temperate coniferous trees in the world being found in the habitat. The region has a high number of endemic amphibians such as the arboreal salamander that lives in the tallest redwoods. Other wildlife unique to the region encompasses the California condor, mountain lions, elk, and brown bears.
The province has a diverse culture that plays a major role in the American consumer market. The Mediterranean climate makes California a hub for agriculture producing half of the food products consumed in the US.
The California Floristic Province faces serious threats from human activities and development. Since it is located in the most populated and fastest growing regions in the US, the biodiversity has been threatened by urbanization, pollution, agriculture, mining, logging, and intentional fires. It is approximated that the salt and freshwater ecosystems have declined by 90% due to land reclamation in favor of development. Only 25% of the hotspot holds its pristine nature, hence great deals of conservation efforts are needed to protect the hotspot.
2. Madrean Pine-oak Woodlands
Madrean pine-oak woodlands is the world’s richest and most endangered terrestrial ecosystem found in the higher elevations of the mountain ranges of Mexico, as well as the US states of Arizona, New Mexico, and Texas. It comprises of different habitats including tropical, subtropical, dry shrublands, and grasslands. The consistent pine, oak, Douglas fir, and fir species coupled with varying orientation of slopes, soil types, climate and geologic history give the hotspot its cohesive character.
There are 5,300 flowering plants with 2,000 species being unique to Madrean Sky Islands. The hotspot is home to the most spectacular wildlife wonders in the world comprising of 525 bird species and 328 species of mammals. The iconic volcano rabbit is one of the most endangers and endemic species occupying the Trans-Mexican Volcanic Belt. Madrean pine-oak woodlands have one of the most spectacular features of overwintering monarch of butterflies found in Michoacan pine forests. Every year during fall, about 500 million monarch butterflies migrate from eastern North America to the south where they form giant clusters on the branches and trunks of trees in the fir ecosystem.
The hotspot is also a center of cultural and ethnic diversity. Ethnic groups in the region include the Chinantec, Cora, Zapotec, Mixtec, and Taharuma. In Mexico, the indigenous communities occupy over half of the country’s protected area of the Sky Island.
Illegal logging poses as the greatest threats to the Pine-Oak woodlands. Non-wood products including the vascular epiphyte are extracted every year for Christmas ointment purposes in Mexico. A variety of mushroom species found in the pine-oak forests are collected for culinary purposes. Intentional fires in favor of grazing field and agriculture have immensely altered habitats throughout the woodland forests. The unique biodiversity of animal and plant species makes Madrean pine-oak woodland an important hotspot that requires conservation.
Spanning most of Central America is the Mesoamerica biodiversity hotspot, which is the third largest among the world’s hotspots. The hotspot comprises of all the tropical and subtropical ecosystems stretching from central Mexico to the Panama Canal. It covers all the countries of Central America including Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Southern Mexico, and two-thirds of Panama. The area also covers nearshore and offshore islands of the Caribbean Sea and the Pacific Ocean such as the Revillagigedos, Tres Marias Islands, and Cozumel.
The biodiversity of this region is a mixture of wildlife from North and South America as well as endemic species. The ecosystem hosts 17,000 vascular plant species of which, 2,900 are endemic to the habitat. In addition, there are 1,113 bird, 440 mammal, 692 reptile, 555 amphibian, and 509 fish species. The tapir and jaguar are the two largest land mammals in the neotropical forests of Mesoamerica.
Cultural diversity adds to the rich biodiversity of Mesoamerica with each country being home to various indigenous tribes including the Mayans of Mexico, colorful bead-decked San Blas tribes of Panama, and the mestizo tribes of indigenous Spanish cultures.
Mesoamerica faces the highest rates of ecological degradation in the world. Up until the 20th century, lowland forests in the Pacific region were cleared in favor of horticultural and subsistence farming. Today, the Caribbean lowland forests are being cleared every day in favor of banana and coffee production. Expansion projects along the Panama Canal and construction of a new canal in Nicaragua present major threats in terms of introduction and invasive species to the marine ecosystem. Although 12% of the Mesoamerica hotspot is protected land, further efforts seeking to integrate sustainable developments with biodiversity management should be implemented by all governments within the hotspot.