The Merced National Wildlife Refuge encompasses of
wetland
A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The p ...
s, native
grassland
A grassland is an area where the vegetation is dominated by grasses ( Poaceae). However, sedge ( Cyperaceae) and rush ( Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur na ...
s,
vernal pool
Vernal pools, also called vernal ponds or ephemeral pools, are seasonal pools of water that provide habitat for distinctive plants and animals. They are considered to be a distinctive type of wetland usually devoid of fish, and thus allow the safe ...
s, and
riparian
A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks a ...
areas in California. It was established in 1951 under the
Lea Act to attract wintering
waterfowl
Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which i ...
from adjacent farmland where their foraging was causing crop damage. In the last few decades, changes in agricultural practices and refuge management have reduced these wildlife/crop issues.
The refuge plays host to the largest wintering populations of
lesser sandhill cranes and
Ross's geese within the
Pacific Flyway
The Pacific Flyway is a major north-south flyway for migratory birds in the Americas, extending from Alaska to Patagonia. Every year, migratory birds travel some or all of this distance both in spring and in fall, following food sources, heading ...
. Each autumn over 20,000 cranes and 60,000 arctic nesting geese terminate their annual migrations from
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S. ...
and
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
to make the refuge home for six months. Here they mingle with thousands of other visiting waterfowl, waterbirds and shorebirds making the refuge a true winter phenomenon.
The refuge also provides important breeding habitat for
Swainson's hawk
Swainson's hawk (''Buteo swainsoni'') is a large bird species in the Accipitriformes order. This species was named after William Swainson, a British naturalist. It is colloquially known as the grasshopper hawk or locust hawk, as it is very fond ...
s,
tri-colored blackbirds,
marsh wren
The marsh wren (''Cistothorus palustris'') is a small North American songbird of the wren family. It is sometimes called the long-billed marsh wren to distinguish it from the sedge wren, also known as the short-billed marsh wren.
Taxonomy
The ma ...
s,
mallards,
gadwall,
cinnamon teal
The cinnamon teal (''Spatula cyanoptera'') is a species of duck found in western North and South America. It is a small dabbling duck, with bright reddish plumage on the male and duller brown plumage on the female. It lives in marshes and ponds ...
, and
burrowing owl
The burrowing owl (''Athene cunicularia''), also called the shoco, is a small, long-legged owl found throughout open landscapes of North and South America. Burrowing owls can be found in grasslands, rangelands, agricultural areas, deserts, or an ...
s. Tri-colored blackbirds, a colonial-nesting
songbird
A songbird is a bird belonging to the suborder Passeri of the perching birds (Passeriformes). Another name that is sometimes seen as the scientific or vernacular name is Oscines, from Latin ''oscen'', "songbird". The Passeriformes contains 5000 ...
, breed in colonies of over 25,000 pairs.
Coyotes,
ground squirrel
Ground squirrels are members of the squirrel family of rodents ( Sciuridae), which generally live on or in the ground, rather than trees. The term is most often used for the medium-sized ground squirrels, as the larger ones are more commonly known ...
s,
desert cottontail
The desert cottontail (''Sylvilagus audubonii''), also known as Audubon's cottontail, is a New World cottontail rabbit, and a member of the family Leporidae. Unlike the European rabbit (''Oryctolagus cuniculus''), they do not form social burrow s ...
rabbits,
beaver, and
long-tailed weasel
The long-tailed weasel (''Neogale frenata''), also known as the bridled weasel, masked ermine, or big stoat, is a species of mustelid distributed from southern Canada throughout all the United States and Mexico, southward through all of Central A ...
s can also be seen year-round.
Vernal pools are another type of wetland found on the Merced National Wildlife Refuge. These special pools form when natural shallow depressions underlaid with clay soils fill with winter rainwater. The pools come to life as they fill with water:
fairy and
tadpole shrimp emerge from
cyst
A cyst is a closed sac, having a distinct envelope and division compared with the nearby tissue. Hence, it is a cluster of cells that have grouped together to form a sac (like the manner in which water molecules group together to form a bubble) ...
s embedded in the soils the previous year. The
endangered
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and in ...
tiger salamander
The tiger salamander (''Ambystoma tigrinum'') is a species of mole salamander and one of the largest terrestrial salamanders in North America.
Description
These salamanders usually grow to a length of with a lifespan of around 12–15 years. ...
, along with other amphibians, lays eggs and rear tadpoles. The vast number of aquatic invertebrates found in these pools provides a food source for wintering and migrating birds as they prepare for the long flight north to their breeding grounds.
As spring arrives and the water in the vernal pools evaporates, wildflowers – such as
goldfields,
purple owl's clover, and
butter-and-eggs – germinate in colorful patterns of thick rings or halos around the pool basins. Once the vernal pools have dried out,
Downingia and
Colusa grass, a rare California species, appear in the parched basins. This annual coloring led
John Muir
John Muir ( ; April 21, 1838December 24, 1914), also known as "John of the Mountains" and "Father of the National Parks", was an influential Scottish-American naturalist, author, environmental philosopher, botanist, zoologist, glaciologist ...
to describe the valley floor as the "floweriest part of the world" he had seen.
In addition to managing natural habitats, the Merced National Wildlife Refuge contains approximately of cultivated
corn and winter
wheat
Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...
crops and over of irrigated pasture for wildlife. Not only do these managed agricultural areas provide important sources of nutrition (
carbohydrate
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or m ...
s) to the tens of thousands of arctic-nesting geese and sandhill cranes that make Merced County their winter home, they also help ensure that the birds will have adequate nutrient stores to make the long migration to their northern breeding grounds. Local farmers, under agreements with the refuge, oversee the ground preparation, seeding, and irrigation of these croplands. The refuge incorporates a livestock grazing program that works in partnership with local ranchers and farmers.
Grazing
In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other ...
cattle
Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult ma ...
and
sheep
Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus '' Ovis'', in everyday usage it almost always refers to domesticated ...
is a management tool used by the refuge to help control invasive
weed
A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place", or a plant growing where it is not wanted.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. ...
s, provide and maintain short stature grasslands for goose grazing, and encourage native grasslands to thrive.
References
Refuge website
External links
*
{{authority control
National Wildlife Refuges in California
Parks in the San Joaquin Valley
San Joaquin River
Wetlands of California
Protected areas of Merced County, California
Natural history of the Central Valley (California)
Geography of Merced County, California
Protected areas established in 1951
1951 establishments in California
Merced National Wildlife Refuge