Aquatic Species

雪儿 · 发表于: 2011-7-14 16:35:01

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Canada Geese

Photograph by Mike Fladeland, My Shot

Canada geese come in for a landing, aiming to get their feet wet despite the morning chill.

Freshwater habitats are critical for these migratory birds, which suffered from wetland destruction and overhunting in the early 20th century. In more recent years, however, the geese have proven adept at living in human-made aquatic habitats like golf courses, parks, and airports—becoming a permanent nuisance, and water quality problem, at some locales.

雪儿 · 发表于: 2011-7-14 16:35:15

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Fishing Lake Tumba

Photograph by Philip Reynaers, My Shot

Two young boys try their luck in the waters of Lake Tumba in the Democratic Republic of the Congo. The lake holds an amazing variety of fish species as well as freshwater crocodiles and hippos.

Freshwater ecosystems cover less than one percent of Earth’s surface, but house 35 percent of all vertebrate species. At Tumba, heavy human migration to Congo and largely unchecked fishing are making it harder to take a meal from the lake.

雪儿 · 发表于: 2011-7-14 16:35:33

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Great Egret

Photograph by Andy Nguyen, My Shot

A large fish proves more than a mouthful for a hungry great egret, which lost its prize soon after this shot was snapped. This big bird may be seen across much of the globe but is nearly always found near water where food is plentiful.

Great egrets depend on aquatic habitats—salt or freshwater—and find food in ponds, wetlands, streams, and tidal flats. But some of their favorite meals may soon be off the menu—40 percent of all North America’s fish species are at risk of extinction.

雪儿 · 发表于: 2011-7-14 16:35:44

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Florida Everglades

Photograph by Getty Images

The Everglades, also referred to as the “River of Grass,” stretches across some 7,800 square miles (20,100 square kilometers) of Florida—an area similar to the size of Massachusetts.

Home to gators, mangroves, and the Florida panther, the Everglades is one of the world’s great wetlands, but human hands have been heavy in draining and developing the region. Perhaps only 2 percent of the original ecosystem is completely intact. Up to 50 percent of the world’s wetlands have similarly disappeared.

雪儿 · 发表于: 2011-7-14 16:35:56

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Hippopotamus

Photograph by Chris Johns

A hippo rears its head from a leafy patch of floating plants on the Zambezi River, which runs through southern Africa.

The massive mammals spend most of their time—as much as 16 hours every day—submerged in river and lake waters that help to keep them cool. At night these “river horses” leave the water and roam overland in search of grasses to sustain their 5,000- to 8,000-pound (2,268- to 3,629-kilogram) frames.

雪儿 · 发表于: 2011-7-14 16:36:08

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Water Lilies and Small Fish

Photograph by George Grall

Long-stemmed water lilies stretch towards the surface, and the sun, while schools of small fish feed in their shade.

The waters of the incredible Cuatro Cienegas (Four Marshes) wetlands, in Mexico’s Chihuahuan Desert, come from aquifers deep underground and thus remain crystal clear. The 500-square-mile (1,295-square-kilometer) region has been isolated from other water systems for millions of years, allowing dozens of endemic species to evolve.

雪儿 · 发表于: 2011-7-14 16:36:22

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Eastern Diamondback Rattlesnake

Photograph by Chris Johns

An eastern diamondback rattlesnake stretches across the roots of a mangrove tree in the waters of Everglades National Park, Florida.

Mangroves are specially adapted to living partially submerged in brackish waters like those found in the Everglades. These trees are one of some 700 different tropical- and temperate-plant species that call the Everglades home.

雪儿 · 发表于: 2011-7-14 16:36:34

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Coahuilan Box Turtles

Photograph by George Grall

To escape the hot Mexican Chihuahuan desert sun, Coahuilan box turtles chill in the waters of Laguna de los Burros.

Unique among the world’s box turtles, these endangered animals are aquatic and spend perhaps 90 percent of their day in the springs, rivers, and pools of Mexico’s Cuatro Cienegas wetlands. Only a few thousand of the turtles exist, and since the 1960s, their habitat has been cut in half by irrigation and drought.

Worldwide, freshwater species extinction rates are four to six times higher than those of terrestrial or marine species.

雪儿 · 发表于: 2011-7-14 16:36:48

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Water Lily and Dragonfly

Photograph by Frank Curtis, My Shot

A dragonfly in full flight heads for a floating water lily to quench its thirst. The three-foot-diameter (one-meter-diameter) lily collected rainfall and formed a small freshwater pool that proved irresistible to this insect inhabitant of Venetian Gardens in Leesburg, Florida.

Water lilies are popular ornamentals, but as invasive species they can overwhelm bodies, pushing out native species and altering aquatic ecosystems.

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[其他] Aquatic Species

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