The United States is a country situated in North America. It consists of fifty states and covers an area of 3,796,742 square miles making it the third-largest country by land area. The country is also known for its biodiversity, which is spread out across various distinct habitats. According to some of the latest estimates, the country is home to over 200,000 species. That figure only includes species that have been formally named and studied by scientists, which means that more plants, animals, and microbes are yet to be discovered. Over 1,800 species of flowering plants are found across various states in the country. Unfortunately, 40.7% of them are endangered due to environmental degradation, air, and water pollution. The United States is particularly rich in aquatic life including fish, salamanders, turtles, and mussels. For example, the Tennessee River has more fish species than all of Europe. The country’s flora and fauna are, however, not faring well, one-third of species in the country are currently at risk or of conservation concern. Over 500 species are already extinct or missing. At least 100 of those species are presumed extinct and have disappeared forever, while 439 species are missing and feared lost. About 60% of the nation’s territory outside of Alaska has also lost a considerable portion of natural vegetation.
About 733 species of flowering plants are estimated to be endangered. Studies have found that declining plant diversity due to human use, habitat loss, and other environmental pressures are leading plants to flower earlier. Scientists have also found that the effects of loss of diversity on the timing of flowering are comparable to the effects of global warming on flowering plants. Some of the plants on the endangered list include the White sedge Star cactus, Island Barberry, Texas poppy-mallow, Capa rosa. Native flowering plants in the country are threatened by human activity, invasive plants, and climate change. Invasive plants are defined as foreign/non-native plant species whose introduction to an ecosystem causes harm to native plants or humans. The US currently spends $100 billion annually to control invasive plant species.
Ninety-four species of fish are currently listed as endangered. Fishes are considered appropriate indicators of aquatic biodiversity since their wide variety reflects a wide range of environmental conditions. Fish also influence the abundance and distribution of other organisms found in the waters they inhabit. Some of the fish on the endangered list include White sturgeon, Shortnose Sucker, Desert pupfish, Smalltooth sawfish, Dwarf sawfish, Atlantic salmon, Alabama cavefish, and Pallid Sturgeon. Freshwater fauna is on the decline across the world. Fish species that face the highest risk of extinction are either endemic with small distributions or specialized for life in large rivers. Some of the causes of the decline in fish species include pollution, habitat alteration, commercial exploitation, the introduction of exotic species, and competition for water. Some of the proposed ways of protecting biodiversity include the restoration of degraded aquatic habitats and the creation of marine reserves.
Seventy-seven species of birds in the United States are currently listed as endangered. At least 13 bird species have gone extinct in the Americas in the last 50 years (mainly in Hawaii). The extinction of seven species has been averted in the Americas since 1994. Habitat loss is considered the principal threat facing most of the species in the country. Some of the bird species currently listed as endangered include the Akikiki, Laysan duck, Puerto Rican nightjar, Ivory-billed woodpecker, Hawaiian coot, California condor, White-necked crow Mississippi sandhill crane, Whooping crane, Molokai thrush, Guam rail, Thick-billed parrot, and the Everglade snail kite.
Clams or America’s Mussels are a group of animals that lie at the bottom of rivers, lakes, and creeks that rarely move and feed by filtering water for microscopic food particles. Clams can even reproduce without moving, and males typically disperse sperm that is carried by water currents to females where fertilization happens. They are often mistaken for rocks. North America has the highest number of freshwater mussel species in the world. States in the Midwest, including Minnesota, Iowa, Wisconsin, Illinois, Indiana, Missouri, and Ohio have some of the highest clam species in North America. There are currently 76 clam species listed as endangered. They include the Dwarf wedge-mussel, Cumberland Elkton, Appalachian elktoe, Fan shell, Oyster mussel, Curtis pearly-mussel, Upland comb-shell, Southern comb-shell, Neosho Mucket, Snuffbox mussel, Shiny pigtoe, Carolina heel-splitter, and the Alabama lamp mussel. Habitat destruction has been identified as one of the main reasons behind the decline of clam species. Habitat destruction is caused by dredging, channelization, dams, siltation, and contaminants. Some of the other threats facing the endangered species include the introduction of non-indigenous species, overutilization for commercial purposes, predation, disease, hybridization, and pollution.
There are 74 species of insects listed as endangered in the United States. They include the Florida leafwing butterfly, Miami tiger beetle, San Bruno elfin butterfly, Casey’s June beetle, Hawaiian picture-wing fly, Smith’s blue butterfly, Hawaiian yellow-faced bee, and the American burying beetle. Significant threats to insects in the United States include habitat destruction, hybridization, pollution, and displacement by introduced species. Species with a restricted range are particularly vulnerable. For example, the Tahoe stonefly (Capnia lacustra), which is currently listed as endangered is only found in Lake Tahoe in California at depths of 196-262 feet. It is the only species of stonefly in the world that is fully aquatic in the adult stage. The main impediment to insect conservation and integration of insects to mainstream conservation policy research is the lack of dedicated funding to support research programs relating to the conservation of insects and their habitats.
The US is home to 416 species of mammal, which is about 9% of the world’s total. Sixty-six mammal species are, however, listed as endangered. Some of the species on the list include the Gray wolf, Finback whale, Blue whale, Mexican wolf, Giant Kangaroo rat, Red wolf, Steller sea lion, Pacific sheath-tailed bat, Ocelot, Indiana bat, Gray bat, Jaguar, Alabama beach mouse, Ringed seal, San Joaquin kit fox, and the Florida panther. The Red wolf is critically endangered. The species was once found throughout south-eastern part of the country. The species was almost going extinct before the intervention of the US Fish and Wildlife Service in 1973. Wild wolves were captured and bred in captivity in facilities such as the Point Defiance Zoological Garden in Tacoma before being released back into the wild.
American snails remain largely understudied. There are currently 40 species of snail listed as endangered, and they include the Oahu tree snail, Anthony’s river-snail, Slender Campelona, Black Abalone, White Abalone, and Plicate rock-snail. Others include Flat pebblesnail, Guam tree snail, Rough horn-snail, Diamond Tryonia, and the Roswell sparing-snail. In Hawaii, the critically endangered Achatinella fuscobasis snail has been brought into captivity to help scientists study methods of conserving the species. Snails are particularly challenging to conserve since their habitats are extremely fragile. Snails also have narrow microhabitat requirements that make them difficult to conserve. For example, one species of snail might only feed on fungi species that are unique to a particular forest.
Ferns And Allies
Ferns and lycophytes are ecologically important as they contribute 4% of vascular plant diversity on Earth. However, they are currently facing unprecedented threats caused by human disturbances such as land-use change and fires. Some species benefit from such disturbances, but most of the species become less abundant or locally extinct. There are 35 species of ferns and allies listed as endangered in the US. Current risk assessments are mainly based on abundance and geographical range. Some of the species of ferns and allies currently listed as endangered include Pendant kihifern, Asplenium-leaved diellia, Elfin tree fern, Pauoa, Palapalai aumakua, Louisiana quillwort, Black spored quillwort, Aleutian shield fern, and the Florida bristle fern.
Crustaceans are invertebrate animals that belong to the phylum Arthropoda and subphylum Crustacea. They include crabs, crayfish, shrimp, lobster, and the water flea. They can be found in a variety of environments in the sea and on land. Although they are extremely varied, crustaceans typically have a body that consists of a head, thorax, and abdomen, a hard exoskeleton, two pairs of antennae, and two eyes. There are 24 species of endangered crustaceans in the US. Some of the crustaceans that are currently listed as endangered in the US include the Longhorn fairy shrimp, Illinois cave amphipod, Noel’s Amphipod, Nashville crayfish, Socorro isopod, Kentucky cave shrimp, California freshwater shrimp, and the Alabama cave shrimp. Crustaceans in small isolated populations are particularly vulnerable. For example, the Kentucky cave shrimp is found exclusively in Kentucky in underground streams in the surrounding Mammoth Cave National Park. The main threats to the species are poor water quality, siltation, habitat destruction, and contamination of groundwater.
Amphibians And Reptiles
Some of the endangered amphibians include the Wyoming toad, Ozark hellbender, Sonora tiger salamander, dusky gopher frog, Houston toad, and the Austin blind salamander. Reptiles listed as endangered include the Leatherback sea turtle, Puerto Rican boa, Alabama red-bellied turtle, Loggerhead sea turtle, Blunt-nosed leopard lizard, and Green sea turtle.
Other types of organisms listed as endangered species include Arachnids (12), Lichens (2), and Conifers and cycads (1).
Conservation Of Endangered Animals
The Endangered Species Act is one of the most important environmental laws in the United States. Passed in 1973, the law allows organizations, and individuals to petition to have a species listed as threatened or endangered. The law is credited for helping prevent the extinction of animals including, grey whales, bald eagles, and the peregrine falcon. The law requires the development and implementation of recovery plans for listed species and protection of critical habitat areas. It also requires coordination between federal, state, tribal, and local officials on measures and efforts aimed at conservation.
Number Of Endangered Plants And Animals By Type In The United States
|Number of endangered species in the US
|Ferns and Allies
|Conifers and cycads