Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They include lakes, ponds, rivers, streams, springs, bogs, and wetlands. They can be contrasted with marine ecosystems, which have a larger salt content. Freshwater habitats can be classified by different factors, including temperature, light penetration, nutrients, and vegetation. There are three basic types of freshwater ecosystems: Lentic, lotic and wetlands. Freshwater ecosystems contain 41% of the world's known fish species.
The ecology of the Sierra Nevada, located in the U.S. states of California and Nevada, is diverse and complex. The combination of climate, topography, moisture, and soils influences the distribution of ecological communities across an elevation gradient from 500 to 14,500 feet. Biotic zones range from scrub and chaparral communities at lower elevations, to subalpine forests and alpine meadows at the higher elevations. Particular ecoregions that follow elevation contours are often described as a series of belts that follow the length of the Sierra Nevada. There are many hiking trails, paved and unpaved roads, and vast public lands in the Sierra Nevada for exploring the many different biomes and ecosystems.
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 development of natal amphibian and insect species unable to withstand competition or predation by fish. Certain tropical fish lineages have however adapted to this habitat specifically.
Aquilegia canadensis, the Canadian or Canada columbine, eastern red columbine, or wild columbine, is a species of flowering plant in the buttercup family Ranunculaceae. It is an herbaceous perennial native to woodland and rocky slopes in eastern North America, prized for its red and yellow flowers. It readily hybridizes with other species in the genus Aquilegia.
The blue-billed duck is a small Australian stiff-tailed duck, with both the male and female growing to a length of 40 cm (16 in). The male has a slate-blue bill which changes to bright-blue during the breeding season, hence the duck's common name. The male has deep chestnut plumage during breeding season, reverting to a dark grey. The female retains black plumage with brown tips all year round. The duck is endemic to Australia's temperate regions, inhabiting natural inland wetlands and also artificial wetlands, such as sewage ponds, in large numbers. It can be difficult to observe due to its cryptic nature during its breeding season through autumn and winter. The male duck exhibits a complex mating ritual. The blue-billed duck is omnivorous, with a preference for small aquatic invertebrates. BirdLife International has classified this species as Least concern. Major threats include drainage of deep permanent wetlands, or their degradation as a result of introduced fish, peripheral cattle grazing, salinization, and lowering of ground water.
Siblicide is the killing of an infant individual by its close relatives. It may occur directly between siblings or be mediated by the parents, and is driven by the direct fitness benefits to the perpetrator and sometimes its parents. Siblicide has mainly, but not only, been observed in birds.
Polystichum aculeatum, the hard shield-fern, is an evergreen fern native to Europe. It is most abundant in upland regions of the British Isles and western France, where it benefits from the combination of mild winters and moist summers, but also occurs more locally across most of Europe except northern Scandinavia, northern Russia; in the Mediterranean region it is confined to high altitudes. It grows on steep slopes in woodlands. it is sometimes considered an indicator of the presence of ancient woodlands.
Veronica serpyllifolia, the thyme-leaved speedwell or thymeleaf speedwell, is a perennial flowering plant in the plantain family. It is native to Europe, but can be found elsewhere on most continents as an introduced species.
Facultative means "optional" or "discretionary", used mainly in biology in phrases such as:
Eleocharis halophila, the saltmarsh spikerush, is a perennial halophytic plant endemic to salt marshes in eastern Canada, in Ontario in Hudson Bay and James Bay, Quebec in the St. Lawrence Seaway as far as the city of Quebec, Newfoundland and Nova Scotia and in the United States from Maine to North Carolina. It is one of 76 species of Eleocharis amongst the 36 genera in the sedge family (Cyperaceae).
Salicornia virginica is a halophytic perennial dicot which grows in various zones of intertidal salt marshes and can be found in alkaline flats. It is native to various regions of the Northern Hemisphere including both coasts of North America from Canada to Mexico.
Carex paleacea, the chaffy sedge, is one of the 579 species of Carex. The Wetland Indicator Status for the species is classified as "obligate wetland" (OBL), occurring 99% of the time in a typical salt marsh environment when conditions are favorable.
Lonicera canadensis is a flowering deciduous, perennial, phanerophytic shrub which is monoclinous and grows 1–2 m tall. It typically flowers from the last week of April until the third or fourth week of May. Fruit appears approximately the first week of June until the first week of August. The fruit is fed upon by a variety of avian frugivores including the American Robin and Northern Cardinal.
Cirsium lecontei, often called the Le Conte's thistle, is a North American plant species native to the southeastern United States. It is a perennial, or sometimes biennial, species of the tribe Cardueae within the family Asteraceae. It grows along the coastal plain from Louisiana to North Carolina.
Symphyotrichum dumosum is a species of flowering plant of the family Asteraceae commonly known as rice button aster and bushy aster. It is native to much of eastern and central North America, as well as Haiti and Dominican Republic. It is a perennial, herbaceous plant that may reach a height of 1 meter.
Leucospora multifida, known variously as Obi-Wan conobea, narrow-leaved paleseed, cliff conobea, cut-leaved conobea, or much-cleft conobea, is an annual herb in the plantain family, Plantaginaceae, and the only species in the North American genus Leucospora.
Hypericum canadense, known as Canadian St. Johns-wort, lesser St. John's wort, and lesser Canadian St. Johnswort, is a flowering plant in the genus Hypericum. It is a yellow-flowering annual or perennial herb native to North America and introduced to Ireland and The Netherlands. The specific epithet canadense means "Canadian".
Sesbania vesicaria, commonly known as the bagpod or bladder pod, is a plant in the legume family native to North America. This species is a facultative hydrophyte occurring in wetlands and non-wetland areas. It is one of the 60 identified species in the genus Sesbania.
Endangered species as classified by the International Union for Conservation of Nature (IUCN), are species which have been categorized as very likely to become extinct in their known native ranges in the near future. On the IUCN Red List, endangered is the second-most severe conservation status for wild populations in the IUCN's schema after critically endangered. In 2012, the IUCN Red List featured 3,079 animal and 2,655 plant species as endangered worldwide. The figures for 1998 were 1,102 and 1,197 respectively.
