This includes 40 percent of amphibians, 34 percent of conifers, 33 percent of reef-building corals , 25 percent of mammals and 14 percent of birds. In the U. While it may seem unimportant if we lose one salamander or rat species, it matters because all species are connected through their interactions in a web of life.
A balanced and biodiverse ecosystem is one in which each species plays an important role and relies on the services provided by other species to survive. Healthy ecosystems are more productive and resistant to disruptions. An often-cited example is the impact of the wolves in Yellowstone Park, which were hunted to near extinction by Without them, the elk and deer they had preyed upon thrived, and their grazing decimated streamside willows and aspens, which had provided habitat for songbirds.
This left the stream banks susceptible to erosion, and a decline in songbirds allowed mosquitoes and other insects the birds would have eaten to multiply. When the wolves were reintroduced to the park in , they once again preyed on the elk; plant life returned to the stream banks and along with it, birds, beavers, fish and other animals. Note: David Bernhardt, acting secretary of the Department of the Interior, just announced a proposal to strip gray wolves of their endangered status in the Lower 48 states.
Kelp forests are another classic example. They play an important role in coastal ecosystems because they provide habitat for other species, protect the coastline from storm surges and absorb carbon dioxide. Otter in a kelp field. Photo: Doug Knuth. Yet kelp forests are rapidly getting mowed down by exploding numbers of purple sea urchin. California sea otters eat the purple sea urchins that feed on giant kelp.
These otters used to number in the hundreds of thousands to millions, but their population has been reduced to about 3, as a result of unchecked hunting in the 19th century and pollution. Moreover, in the sunflower starfish, which also eats purple sea urchins, began dying because of a virus that was likely exacerbated by warmer waters. Without the sea otter and the sunflower starfish predators, the purple sea urchin began feasting on the kelp forests, which declined 93 percent between and A new study found that kelp forests are now also threatened by ocean heat waves.
Fish that need the kelp forests for spawning, such as sculpin, rock cod and red snapper may become vulnerable in the future as well. And Guam is covered in spiders because the birds are not there to eat them. These large species are more vulnerable because they live longer, reproduce more slowly, have small populations, and need more food and a greater habitat area. Scientists say their loss has played a role in pandemics, fires, the decline of valued species and the rise of invasive ones, the reduction of ecosystem services, and decreased carbon sequestration.
Elephants are an apex species that may go extinct in our lifetime, as a result of tourism, habitat loss and poaching for ivory. This could dramatically change ecosystems in Africa and Asia. Through consumption and digestion, elephants disperse more seeds farther than any other animals; this fosters the growth of plants and trees that birds, bats and other animals depend upon for food and shelter. Photo: Johnny and Rebecca. Elephants also dig water holes that all animals share, and they fertilize the soil with their rich dung, which provides food for other animals.
The loss of apex species can also affect wildfires. After rinderpest, an infectious virus, wiped out many plant-eating wildebeest and buffalo in East Africa in the late s, plants flourished. During the dry season, this over-abundance of vegetation spurred an increase in wildfires. In the s, after rinderpest was eliminated through vaccinations, the wildebeest and buffalo returned. The ecosystem went from shrubbery to grasslands again, decreasing the amount of combustible vegetation, and the wildfires decreased.
The loss of pollinators could result in a decrease in seed and fruit production, leading ultimately to the extinction of many important plants. Flying foxes, also known as fruit bats, are the only pollinators of some rainforest plants. They have been over-hunted in tropical forests with several species going extinct.
One study noted that plant species, including eucalyptus and agave, rely on flying foxes to reproduce; in turn, these plants were responsible for producing valuable products. Bees pollinate over , species of plants, including most of the 87 crops that humans rely on for food, such as almonds, apples and cucumbers. An award-winning environmental journalist, his work has appeared in Scientific American, Audubon, Motherboard, and numerous other magazines and publications. His "Extinction Countdown" column has run continuously since and has covered news and science related to more than 1, endangered species.
John lives on the outskirts of Portland, Ore. Follow John R. Platt on Twitter. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue.
See Subscription Options. Discover World-Changing Science. Here are the 15 extinct species: Barbodes disa —last seen in Barbodes truncatulus —last seen in Barbodes pachycheilus —last seen in Barbodes palaemophagus —last seen in Barbodes amarus —Last seen in Barbodes manalak —Once a commercially valuable fish, last seen in Barbodes clemensi —last seen in Barbodes flavifuscus —last seen in Barbodes katolo —last seen in Barbodes palata —last seen in Barbodes baoulan —last seen in Barbodes lanaoensis —last seen in Barbodes resimus —last seen in Barbodes tras —last seen in Get smart.
Sign up for our email newsletter. Sign Up. Support science journalism. And because we can. But pandas also play a crucial role in China's bamboo forests by spreading seeds and helping the vegetation to grow. So by saving pandas, we will also be saving so much more. We will be helping to protect not only these unique forests but also the wealth of species that live in them, such as dwarf blue sheep and beautiful multi-coloured pheasants.
And we will be providing a lifeline for a host of other endangered animals, including the golden snub-nosed monkey, takin and crested ibis that share these magnificent forests with the panda. And for people across the country. The panda's mountains form the watersheds for both the Yangtze and Yellow rivers, which are the economic heart of China — home to hundreds of millions of people.
Economic benefits derived from these critical basins include tourism, subsistence fisheries and agriculture, transport, hydropower and water resources. Pandas themselves are also economically and culturally valuable.
0コメント