Images

Water levels are critical to the life cycle of alligators. Part of the Everglades restoration plan is to determine what historical water levels and flow rates supported healthy alligator populations.

Beach Sampling for Forage Fish Spawn on Whidbey Island in Puget Sound.

A northern pintail duck wearing a transmitter.

A male northern pintail duck.

California condors are one of the most endangered birds in North America. In the early 1990s, captive-bred condors were reintroduced into the wild in California. As of January 2010, about 190 condors now live in the wild and more reintroductions are being considered.

Sage-grouse have declined throughout their entire range, largely due to the loss and fragmentation of sagebrush habitat.

A colorful clay-colored sparrow nest. These sparrows live in brushy grasslands and prairie habitats.

Elk congregate on the Camp Creek Feed Ground in northwestern Wyoming.

Bighead carp are a large and troublesome invasive species from Asia found in the great rivers of the central United States.

Silver carp are a large a troublesome invasive species from Asia found in the great rivers of the central United States. Silver carp have been observed to jump in response to rocks thrown in the water, passing trains, geese taking off from the water, or just when they unexpectedly find themselves in a tight place.

African rock pythons are the largest snake in Africa, but now some have been found in Florida. They can eat goats, warthogs, and even crocodiles. In Florida, they are an invasive species.

This aerial view shows how Faka Union Canal (visible as a straight channel of water) connects the coastal environment, where manatees feed, to freshwater inlets. The Ten Thousand Islands region in the foreground supports sea grass beds where manatees feed.

A manatee feeds on sea grass beds in Ten Thousand Islands region of Florida.

Image of the silica cell wall of the diatom 'Didymosphenia geminata' from Rio Espolon, Chile. The sample was collected early in 2010 from an extensive bloom on the river. The image has been processed to show the silica cell wall, removing the organic cell contents and the stalk
material.

Drought and climate change are causing extensive forest dieback in the U.S. West as well as worldwide. These photos show dead ponderosa pines in the Jemez Mountains of New Mexico killed by a combination of drought stress and attacks by bark beetles on weakened trees.

Pallid sturgeon caught in the Lower Missouri River.

SRX receivers (left) and a ruggedized laptop computer (right) are essential tools for telemetry tracking on the Lower Missouri River.

Wood frog embryos in a partly ice-covered Wisconsin wetland. Interconnected wetlands and uplands are critical elements of most North American landscapes and support our quality of life in profound ways. To provide much-needed information, the USGS is leading a growing network of U.S.

A brackish marsh in the Mississippi River Delta.

This lichen, Lobaria pulmonaria, is found in northern North America, where it is becoming rare in places.  Lichens -- which are often mistaken for moss -- are unusual plant-like organisms that are actually symbioses of fungi, algae and bacteria living together.

Weighted, small mesh nets (left and right side of the boat attached to winches) are lowered to the bottom of the river near potential spawning sites.  After a set period of time, the nets are raised and the contents are hand-picked for any Acipenseriformes (sturgeon and paddlefish) larvae.  Samples are preserved for laboratory identification and genetic an