Biodiversity is the richness of life in all of its forms, from genes to ecosystems. Biodiversity is not distributed equally over the globe; several factors combine to create so-called hotspots. In this article, we will rank the top 10 most biodiverse states in the USA, based on the distribution of 21,395 plant and animal species represented in the databases of NatureServe1, a non-profit group devoted to supplying information on the status and distribution of biodiversity.
What do you think of when you hear the word biodiversity? You might imagine a tropical rainforest full of colorful birds and exotic plants, or a coral reef teeming with fish and invertebrates. But did you know that the USA is also home to some of the most biodiverse places on Earth? From the deserts of Arizona to the wetlands of Florida, from the mountains of Colorado to the forests of North Carolina, the USA boasts a stunning variety of habitats and ecosystems that support thousands of species of plants and animals.
The Top 10 States for Biodiversity in the USA
In this article, we will explore the top 10 most biodiverse states in the USA, based on the number of species they host and the diversity of their biomes and ecoregions. We will also learn about some of the unique and endangered species that live in these states, and what we can do to protect and conserve their biodiversity for future generations.
| Rank | State | Number of Species | Biomes | Ecoregions |
|---|---|---|---|---|
| 1 | California | 5,653 | Mediterranean forests, woodlands, and scrub; temperate coniferous forests; deserts and xeric shrublands; temperate broadleaf and mixed forests | 13 |
| 2 | Texas | 5,047 | Temperate grasslands, savannas, and shrublands; deserts and xeric shrublands; tropical and subtropical moist broadleaf forests; temperate broadleaf and mixed forests | 10 |
| 3 | Arizona | 4,462 | Deserts and xeric shrublands; temperate coniferous forests; temperate grasslands, savannas, and shrublands; Mediterranean forests, woodlands, and scrub | 9 |
| 4 | New Mexico | 4,032 | Deserts and xeric shrublands; temperate coniferous forests; temperate grasslands, savannas, and shrublands; Mediterranean forests, woodlands, and scrub | 9 |
| 5 | Florida | 3,926 | Tropical and subtropical moist broadleaf forests; temperate broadleaf and mixed forests; mangroves; flooded grasslands and savannas | 7 |
| 6 | Alabama | 3,904 | Temperate broadleaf and mixed forests; temperate coniferous forests; flooded grasslands and savannas; mangroves | 6 |
| 7 | Georgia | 3,832 | Temperate broadleaf and mixed forests; temperate coniferous forests; flooded grasslands and savannas; mangroves | 6 |
| 8 | North Carolina | 3,823 | Temperate broadleaf and mixed forests; temperate coniferous forests; flooded grasslands and savannas; mangroves | 6 |
| 9 | Tennessee | 3,802 | Temperate broadleaf and mixed forests; temperate coniferous forests; flooded grasslands and savannas; mangroves | 6 |
| 10 | Colorado | 3,783 | Temperate coniferous forests; deserts and xeric shrublands; temperate grasslands, savannas, and shrublands; montane grasslands and shrublands | 8 |
California
The richness of California’s flora makes it a biodiversity hotspot even in global comparisons. A lot of that diversity is driven by the large variety of landscapes found in California, including the driest of deserts, lush coastal coniferous forests, salt marshes, and alpine tundra. Mostly separated from the rest of the continent by high-elevation mountain ranges, the state has a large number of endemic species. The Channel Islands off California’s southern coast provided even more opportunities for the evolution of unique species.
Texas
Like in California, the species richness in Texas comes from the state’s sheer size and the variety of ecosystems present. In a single state, one can encounter ecological elements from the Great Plains, the southwestern deserts, the rainy Gulf Coast, and the Mexican subtropics along the Rio Grande. In the heart of the state, the Edwards Plateau (and its numerous limestone caves) holds a rich diversity and many unique plants and animals. The Golden-cheeked Warbler is a Texas endemic relying on the juniper-oak woodlands of the Edwards Plateau.
Arizona
At the junction of several great arid ecoregions, Arizona’s species richness is dominated by desert-adapted plants and animals. The Sonoran Desert in the southwest, the Mojave Desert in the northwest, and the Colorado Plateau in the northeast each bring a unique suite of arid land species. The high-elevation woodlands in the mountain ranges add to this biodiversity, especially in the southeast portion of the state. There, small mountain ranges collectively referred to as the Madrean Archipelago carry pine-oak forests more typical of the Mexican Sierra Madre, and along with them species reaching the very northern end of their distribution.
Thanks to a variety of habitats across the state, Arizona is one of the most biologically diverse states in the nation, ranking third in the number of native bird species, second for reptiles, fifth for mammals, and eighth for overall vertebrate diversity2. In total, Arizona is home to more than 800 native fish and wildlife species, the highest biodiversity of any inland state3.
New Mexico
This state’s rich biodiversity also comes from being at the intersection of several major ecoregions, each with unique plants and animals. For New Mexico, much of the biodiversity comes from the Great Plains influences in the east, the Rocky Mountains incursion in the north, and the botanically diverse Chihuahuan Desert in the south. There are small but significant inclusions of the Madrean Archipelago in the southwest and the Colorado Plateau in the northwest. New Mexico also boasts a high number of endemic species, especially among plants and reptiles. Some examples are the Sandia hairstreak butterfly, found only on beargrass plants in central New Mexico; and Jemez Mountain salamander, restricted to moist habitats under logs and rocks in a small area of northern New Mexico.
Florida
Florida is well-known for its rich and diverse wildlife, especially its reptiles and birds. The state has a subtropical climate that supports many species that are not found elsewhere in the USA. Florida also has a long coastline with extensive wetlands, mangroves, coral reefs and seagrass beds that provide habitat for marine life. Florida has more than 500 native vertebrate species, including 196 fish, 142 amphibians and reptiles, 89 mammals and 84 birds. Some of Florida’s iconic species are the American alligator, Florida panther, manatee and roseate spoonbill. Florida also has many invasive species that threaten its native biodiversity, such as the Burmese python, lionfish and Brazilian Peppertree.
Alabama
Alabama is a surprising hotspot for biodiversity in North America. It has more species of freshwater fish, mussels, snails, turtles and crayfish than any other state. It also has a high diversity of plants, especially flowering plants and ferns. Alabama’s biodiversity is largely due to its geological history, which created a variety of habitats such as mountains, rivers, wetlands and coastal plains. Alabama also has a long history of human settlement and land use change that have impacted its natural resources. Some of Alabama’s endangered species are Alabama red-bellied turtle, Alabama cavefish and Alabama sturgeon. With more than 6,350 species, Alabama ranks fourth among states in terms of overall species diversity and is first among states east of the Mississippi River.
Georgia
Georgia is another state with a rich and diverse wildlife heritage. It has more than 4,000 native plant species and more than 1,000 vertebrate animal species. Georgia’s biodiversity is influenced by its location at the crossroads of several major ecoregions: the Appalachian Mountains in the north, the Atlantic Coastal Plain in the east and south, and the Piedmont Plateau in the center. Georgia also has a long coastline with barrier islands, salt marshes and estuaries that support marine life. Some of Georgia’s notable species are gopher tortoise, loggerhead sea turtle and Georgia aster.
North Carolina
North Carolina is a state with a wide range of habitats and ecosystems, from the highest mountains in the eastern USA to the sandy beaches of the Atlantic Ocean. North Carolina has more than 5,500 plant species and more than 1,500 animal species. North Carolina’s biodiversity is enhanced by its climatic diversity, which ranges from humid subtropical in the east to humid continental in the west. North Carolina also has a rich cultural and historical heritage that influences its conservation efforts. Some of North Carolina’s threatened or endangered species are red wolf, Venus flytrap and Carolina northern flying squirrel.
Tennessee
Tennessee is a state with a remarkable diversity of natural features and wildlife. It has more than 3,800 plant species and more than 1,400 animal species. Tennessee’s biodiversity is shaped by its geology, which includes three major divisions: the Blue Ridge Mountains in the east, the Highland Rim and Nashville Basin in the center, and the Gulf Coastal Plain in the west. Tennessee also has more than 60,000 miles of rivers and streams that drain into three major river systems: the Tennessee River, the Cumberland River and the Mississippi River. Some of Tennessee’s endemic or rare species are Tennessee purple coneflower, Nashville crayfish and Tennessee cave salamander. Today, Tennessee is one of the most biodiverse states in the nation. Currently there are more than 325 species of fish, 89 mammals, 61 reptiles, 70 amphibians, and 340+ birds known to inhabit or migrate through Tennessee.
Colorado
Colorado is a state with a stunning diversity of landscapes and ecosystems, from the high peaks of the Rocky Mountains to the shortgrass prairies of the eastern plains. Colorado has more than 3,500 plant species and more than 1,000 animal species. Colorado’s biodiversity is influenced by its elevation gradient, which creates different climatic zones and vegetation types along the mountains. Colorado also has a complex hydrology, with rivers flowing into four major basins: the Colorado River, the Rio Grande, the Arkansas River and the Platte River. Some of Colorado’s iconic species are bighorn sheep, black bear and Colorado blue columbine.
Conclusion
The USA is a vast and diverse country with a wealth of natural resources and wildlife. Each state has its own unique features and challenges for conservation. The top 10 most biodiverse states in the USA are California, Texas, Arizona, New Mexico, Florida, Alabama, Georgia, North Carolina, Tennessee and Colorado. These states represent different regions and biomes of the country and host thousands of species of plants and animals. By protecting and restoring these states’ biodiversity, we can ensure a healthy and resilient future for ourselves and generations to come.
