The habitat of the garter snake ranges from forests, fields, prairies, streams, wetlands, meadows, marshes, and ponds. It is often found near water and is semi-aquatic. Found at altitudes ranging from sea level to mountain locations.
Habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant, or other type of organism. It is the natural environment in which an organism lives, or the physical environment that surrounds (influences and is utilized by) a species population.
The area or natural environment in which an organism or population normally lives. A habitat is made up of physical factors such as soil, moisture, range of temperature, and availability of light as well as biotic factors such as the availability of food and the presence of predators. A habitat is not necessarily a geographic area—for a parasitic organism it is the body of its host or even a cell within the host's body.
The term microhabitat is often used to describe small-scale physical requirements of a particular organism or population.
The monotypic habitat occurs in botanical and zoological contexts, and is a component of conservation biology. In restoration ecology of native plant communities or habitats, some invasive species create monotypic stands that replace and/or prevent other species, especially indigenous ones, from growing there. A dominant colonization can occur from retardant chemicals exuded, nutrient monopolization, or from lack of natural controls such as herbivores or climate, that keep them in balance with their native habitats. The Centaurea solstitialisyellow starthistle, , is a botanical monotypic-habitat example of this, currently dominating over 15,000,000 acres (61,000 km2) in California alone. The non-native freshwater Dreissena polymorphazebra mussel, , that colonizes areas of the Great Lakes and the Mississippi River watershed, without its home-range predator control, is a zoological monotypic-habitat example.
Even though its name may seem to imply simplicity as compared with polytypic habitats, the monotypic habitat can be complex.
An aquatic ecosystem is an ecosystem in a body of water. Communities of organisms that are dependent on each other and on their environment live in aquatic ecosystems. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems.
Marine ecosystems cover approximately 71% of the Earth's surface and contain approximately 97% of the planet's water. They generate 32% of the world's net primary production. They are distinguished from freshwater ecosystems by the presence of dissolved compounds, especially salts, in the water. Approximately 85% of the dissolved materials in seawater are sodium and chlorine. Seawater has an average salinity of 35 parts per thousand (ppt) of water. Actual salinity varies among different marine ecosystems.
Marine ecosystems can be divided into many zones depending upon water depth and shoreline features. The oceanic zone is the vast open part of the ocean where animals such as whales, sharks, and tuna live. The benthic zone consists of substrates below water where many invertebrates live. The intertidal zone is the area between high and low tides; in this figure it is termed the littoral zone. Other near-shore (neritic) zones can include estuaries, salt marshes, coral reefs, lagoons and mangrove swamps. In the deep water, hydrothermal vents may occur where chemosynthetic sulfur bacteria form the base of the food web.
Classes of organisms found in marine ecosystems include brown algae, dinoflagellates, corals, cephalopods, echinoderms, and sharks. Fishes caught in marine ecosystems are the biggest source of commercial foods obtained from wild populations.
Environmental problems concerning marine ecosystems include unsustainable exploitation of marine resources (for example overfishing of certain species), marine pollution, climate change, and building on coastal areas.
Freshwater ecosystems cover 0.80% of the Earth's surface and inhabit 0.009% of its total water. They generate nearly 3% of its net primary production. Freshwater ecosystems contain 41% of the world's known fish species.
There are three basic types of freshwater ecosystems:
Lake ecosystems can be divided into zones. One common system divides lakes into three zones (see figure). The first, the littoral zone, is the shallow zone near the shore. This is where rooted wetland plants occur. The offshore is divided into two further zones, an open water zone and a deep water zone. In the open water zone (or photic zone) sunlight supports photosynthetic algae, and the species that feed upon them. In the deep water zone, sunlight is not available and the food web is based on detritus entering from the littoral and photic zones. Some systems use other names. The off shore areas may be called the pelagic zone, and the aphotic zone may be called the profundal zone. Inland from the littoral zone one can also frequently identify a riparian zone which has plants still affected by the presence of the lake—this can include effects from windfalls, spring flooding, and winter ice damage. The production of the lake as a whole is the result of production from plants growing in the littoral zone, combined with production from plankton growing in the open water.
Wetlands can be part of the lentic system, as they form naturally along most lakeshores, the width of the wetland and littoral zone being dependent upon the slope of the shoreline and the amount of natural change in water levels, within and among years. Often dead trees accumulate in this zone, either from windfalls on the shore or logs transported to the site during floods. This woody debris provides important habitat for fish and nesting birds, as well as protecting shorelines from erosion,
Two important subclasses of lakes are ponds, which typically are small lakes that intergrade with wetlands, and water reservoirs. Over long periods of time, lakes, or bays within them, may gradually become enriched by nutrients and slowly fill in with organic sediments, a process called succession. When humans use the watershed, the volumes of sediment entering the lake can accelerate this process. The addition of sediments and nutrients to a lake is known as eutrophication.
Ponds are small bodies of freshwater with shallow and still water, marsh, and aquatic plants. They can be further divided into four zones: vegetation zone, open water, bottom mud and surface film. The size and depth of ponds often varies greatly with the time of year; many ponds are produced by spring flooding from rivers. Food webs are based both on free-floating algae and upon aquatic plants. There is usually a diverse array of aquatic life, with a few examples including algae, snails, fish, beetles, water bugs, frogs, turtles, otters and muskrats. Top predators may include large fish, herons, or alligators. Since fish are a major predator upon amphibian larvae, ponds that dry up each year, thereby killing resident fish, provide important refugia for amphibian breeding. Ponds that dry up completely each year are often known as vernal pools. Some ponds are produced by animal activity, including alligator holes and beaver ponds, and these add important diversity to landscapes.
The major zones in river ecosystems are determined by the river bed's gradient or by the velocity of the current. Faster moving turbulent water typically contains greater concentrations of dissolved oxygen, which supports greater biodiversity than the slow moving water of pools. These distinctions forms the basis for the division of rivers into upland and lowland rivers. The food base of streams within riparian forests is mostly derived from the trees, but wider streams and those that lack a canopy derive the majority of their food base from algae. Anadromous fish are also an important source of nutrients. Environmental threats to rivers include loss of water, dams, chemical pollution and introduced species. A dam produces negative effects that continue down the watershed. The most important negative effects are the reduction of spring flooding, which damages wetlands, and the retention of sediment, which leads to loss of deltaic wetlands.
Wetlands are dominated by vascular plants that have adapted to saturated soil. There are four main types of wetlands: swamp, marsh, fen and bog (both fens and bogs are types of mire). Wetlands are the most productive natural ecosystems in the world because of the proximity of water and soil. Hence they support large numbers of plant and animal species. Due to their productivity, wetlands are often converted into dry land with dykes and drains and used for agricultural purposes. The construction of dykes, and dams, has negative consequences for individual wetlands and entire watersheds. Their closeness to lakes and rivers means that they are often developed for human settlement. Once settlements are constructed and protected by dykes, the settlements then become vulnerable to land subsidence and ever increasing risk of flooding. The Louisiana coast around New Orleans is a well-known example; the Danube Delta in Europe is another.
Aquatic ecosystems perform many important environmental functions. For example, they recycle nutrients, purify water, attenuate floods, recharge ground water and provide habitats for wildlife. Aquatic ecosystems are also used for human recreation, and are very important to the tourism industry, especially in coastal regions.
The health of an aquatic ecosystem is degraded when the ecosystem's ability to absorb a stress has been exceeded. A stress on an aquatic ecosystem can be a result of physical, chemical or biological alterations of the environment. Physical alterations include changes in water temperature, water flow and light availability. Chemical alterations include changes in the loading rates of biostimulatory nutrients, oxygen consuming materials, and toxins. Biological alterations include over-harvesting of commercial species and the introduction of exotic species. Human populations can impose excessive stresses on aquatic ecosystems. There are many examples of excessive stresses with negative consequences. Consider three. The environmental history of the Great Lakes of North America illustrates this problem, particularly how multiple stresses, such as water pollution, over-harvesting and invasive species can combine. The Norfolk Broadlands in England illustrate similar decline with pollution and invasive species. Lake Pontchartrain along the Gulf of Mexico illustrates the negative effects of different stresses including levee construction, logging of swamps, invasive species and salt water intrusion.
An ecosystem is composed of biotic communities that are structured by biological interactions and abiotic environmental factors. Some of the important abiotic environmental factors of aquatic ecosystems include substrate type, water depth, nutrient levels, temperature, salinity, and flow. It is often difficult to determine the relative importance of these factors without rather large experiments. There may be complicated feed back loops. For example, sediment may determine the presence of aquatic plants, but aquatic plants may also trap sediment, and add to the sediment through peat.
The amount of dissolved oxygen in a water body is frequently the key substance in determining the extent and kinds of organic life in the water body. Fish need dissolved oxygen to survive, although their tolerance to low oxygen varies among species; in extreme cases of low oxygen some fish even resort to air gulping. Plants often have to produce aerenchyma, while the shape and size of leaves may also be altered. Conversely, oxygen is fatal to many kinds of anaerobic bacteria.
Nutrient levels are important in controlling the abundance of many species of algae. The relative abundance of nitrogen and phosphorus can affect determine which species of algae come to dominate. Algae are a very important source of food for aquatic life, but at the same time, if they become over-abundant, they can cause declines in fish when they decay. Similar over-abundance of algae in coastal environments such as the Gulf of Mexico produces, upon decay, a hypoxic region of water known as a dead zone.
The salinity of the water body is also a determining factor in the kinds of species found in the water body. Organisms in marine ecosystems tolerate salinity, while many freshwater organisms are intolerant of salt. The degree of salinity in an estuary or delta may is an important control upon the type of wetland (fresh, intermediate, or brackish), and the associated animal species. Dams built upstream may reduce spring flooding, and reduce sediment accretion, and may therefore lead to saltwater intrusion in coastal wetlands.
Freshwater used for irrigation purposes often absorb levels of salt that are harmful to freshwater organisms.
The biotic characteristics are mainly determined by the organisms that occur. For example, wetland plants may produce dense canopies that cover large areas of sediment—or snails or geese may graze the vegetation leaving large mud flats. Aquatic environments have relatively low oxygen levels, forcing adaptation by the organisms found there. For example, many wetland plants must produce aerenchyma to carry oxygen to roots. Other biotic characteristics are more subtle and difficult to measure, such as the relative importance of competition, mutualism or predation. There are a growing number of cases where predation by coastal herbivores including snails, geese and mammals appears to be a dominant biotic factor.
Autotrophic organisms are producers that generate organic compounds from inorganic material. Algae use solar energy to generate biomass from carbon dioxide and are possibly the most important autotrophic organisms in aquatic environments. Of course, the more shallow the water, the greater the biomass contribution from rooted and floating vascular plants. These two sources combine to produce the extraordinary production of estuaries and wetlands, as this autotrophic biomass is converted into fish, birds, amphibians and other aquatic species.
Chemosynthetic bacteria are found in benthic marine ecosystems. These organisms are able to feed on hydrogen sulfide in water that comes from volcanic vents. Great concentrations of animals that feed on this bacteria are found around volcanic vents. For example, there are giant tube worms (Riftia pachyptila) 1.5m in length and clams (Calyptogena magnifica) 30 cm long.
Heterotrophic organisms consume autotrophic organisms and use the organic compounds in their bodies as energy sources and as raw materials to create their own biomass. Euryhaline organisms are salt tolerant and can survive in marine ecosystems, while stenohaline or salt intolerant species can only live in freshwater environments.
Eutaenia sirtalis tetratænia Cope, 1875
The San Francisco garter snake (Thamnophis sirtalis tetrataenia) is a slender multi-colored subspecies of the common garter snake. Designated as an endangered subspecies since the year 1967, it is endemic to San Mateo County and the extreme northern part of coastal Santa Cruz County in California. Some researchers estimate that there are only 1,000 to 2,000 adult snakes of the subspecies T. s. tetrataenia remaining. However, the full extent of the snakes' habitat has not been fully documented, and many snakes may utilize creeks and other waterways that are currently unexplored. This garter snake prefers wet and marshy areas, and because of its elusive nature, it is difficult to see or capture.
This subspecies of the common garter snake is found in scattered wetland areas on the San Francisco Peninsula from approximately the northern boundary of San Mateo County south along the eastern and western bases of the Santa Cruz Mountains, at least to the Upper Crystal Springs Reservoir, and along the Pacific coast south to Año Nuevo Point, and thence to Waddell Creek in Santa Cruz County. It is difficult to obtain reliable distribution information and population statistics for the San Francisco garter snake, because of the elusive nature of this reptile and the fact that much of the remaining suitable habitat is located on private property that has not been surveyed for the presence of the snake. This subspecies is extremely shy, difficult to locate and capture, and quick to flee to water or cover when disturbed. The U.S. Fish and Wildlife Service has stated that many locations that previously had healthy populations of garter snakes are now in decline due to land development pressure and the filling of wetlands in San Mateo County over the last sixty years. However, in many areas where it still occurs it is not rare, and is actually quite common and can be viewed with good success once its behavior is understood.
The snake’s preferred habitat is a densely vegetated pond near an open hillside where it can sun, feed, and find cover in rodent burrows; however, markedly less suitable habitat can be successfully used. Temporary ponds and other seasonal freshwater bodies are also appropriate. This subspecies avoids brackish marsh areas because its preferred prey, the California red-legged frog (Rana draytonii), cannot survive in saline water. Emergent and bankside vegetation such as cattails (Typha spp.), bulrushes (Scirpus spp.), and spike rushes (Juncus spp. and Eleocharis spp.) apparently are preferred and used for cover. The zone between stream and pond habitats and grasslands or bank sides is characteristically utilized for basking, while nearby dense vegetation or water often provide escape cover. The subspecies occasionally uses floating algal or rush mats, when available.
San Francisco garter snakes forage extensively in aquatic habitats. Adult snakes feed primarily on California red-legged frogs (Rana draytonii), which are federally listed as threatened. They may also feed on juvenile bullfrogs (Rana catesbeiana), but they are unable to consume adults; in fact, adult bullfrogs prey on juvenile garter snakes, and may be a contributing factor in the population decline of the San Francisco garter snake. Newborn and juvenile San Francisco garter snakes depend heavily upon Pacific treefrogs (Hyla regilla) as prey. If newly metamorphosed Pacific treefrogs are not available, the young garter snakes may not survive. San Francisco garter snakes are one of the few animals capable of ingesting the toxic California newt (Taricha torosa) without incurring sickness or death.
Adult snakes sometimes estivate (enter a dormant state) in rodent burrows during Fall and Spring. Along the Pacific Ocean coast, snakes hibernate during the winter, but further inland, if the weather is suitable, this species is known to be active year-round. Recent studies have documented San Francisco garter snake movement over several hundred meters from wetlands to hibernate in upland small mammal burrows. In spite of being reported as a diurnal, captive and specimens housed in an exterior setting, as well as wild snakes were observed foraging nocturnally or crepuscularly on warm evenings.
The San Francisco garter snake mates in the spring or autumn, and the females give birth to live young in June through September, numbering up to two dozen, but averaging about 16 offspring. The young are approximately 12 to 18 centimeters in length and mature in two years time.
For a brief period from 1996 to 2000 there was confusion over the differentiation of the San Francisco garter snake from two other subspecies, known as the California red-sided garter snake (T. s. infernalis) and the Oregon red-spotted garter snake (T. s. concinnus). Barry petitioned the International Commission on Zoological Nomenclature (ICZN) to suppress the changes proposed in 1996 to merge two of these species. In 2000, the ICZN agreed and voted to retain the historical taxonomic arrangement of subspecies within this evolutionary lineage. Accordingly, the subspecies tetrataenia was reaffirmed for the San Francisco garter snake and the races concinnus and infernalis retain their historical definition.
The San Francisco garter snake cohabits ecosystems that host two other species of garter snake: the coast garter snake (Thamnophis elegans terrestris), a subspecies of Western Terrestrial Garter Snake (T. elegans), and the Santa Cruz aquatic garter snake (Thamnophis atratus atratus) a subspecies of the aquatic garter snake (T. atratus). These three subspecies are known to prey upon same foods; however, their preferences are slightly different. Herpetologist Sean Barry notes that they divide up the food resource as follows:
While the findings of the ICZN have given the San Francisco garter snake unique taxonomic standing for now, a molecular study challenges the subspecific status of this population. Janzen analyzed sequences in mitochondrial DNA to determine relationships within the common garter snake (T. sirtalis). Janzen found that molecular evidence differed, often sharply, with the territorial boundaries of subspecies named on phenotypic variation. He further deduced that local environmental forces were more significant in shaping the color patterns shown by the garter snakes than shared common ancestry, and concluded all morphologically based subspecies in the western U.S. to be subject to revision. This result strongly suggests that the color traits that are diagnostic for (T.s. tetrataenia) are the result of local selection rather than long-term isolation from other races of (T. sirtalis) in central California. On the other hand, the article places the three nearest populations of T. s. infernalis to T.s. tetrataenia in Sonoma County, Contra Costa County, and Santa Clara County into a separate group that exhibits an "elevated rate of molecular evolution". The authors suggest that sequencing nuclear DNA may provide a more precise analytical tool to crack some of the ultimate taxonomic quandaries of the San Francisco garter snake and its relatives.
Many of the factors that led to the listing of the San Francisco garter snake in 1967 continue to impact the organism. These environmental elements include loss of habitat from agricultural, commercial and urban development as well as collection by reptile fanciers and breeders. Collection of these endangered animals by private citizens remains illegal.
Grasslands are areas where the vegetation is dominated by grasses (Poaceae), however sedge (Cyperaceae) and rush (Juncaceae) families can also be found. Grasslands occur naturally on all continents except Antarctica. Grasslands are found in most ecoregions of the Earth. For example there are five terrestrial ecoregion classifications (subdivisions) of the temperate grasslands, savannas, and shrublands biome ('ecosystem'), which is one of eight terrestrial ecozones of the Earth's surface.
Grassland vegetation can vary in height from very short, as in chalk where the vegetation may be less than 30 cm (12 in) high, to quite tall, as in the case of North American tallgrass prairie, South American grasslands and African savanna.
Woody plants, shrubs or trees, may occur on some grasslands – forming savannas, scrubby grassland or semi-wooded grassland, such as the African savannas or the Iberian dehesa. Such grasslands are sometimes referred to as wood-pasture or woodland.
As flowering plants, grasses grow in great concentrations in climates where annual rainfall ranges between 500 and 900 mm (20 and 35 in). The root systems of perennial grasses and forbs form complex mats that hold the soil in place.
Graminoids are among the most versatile life forms. They became widespread toward the end of the Cretaceous period, and fossilized dinosaur dung (coprolites) have been found containing phytoliths of a variety of grasses that include grasses that are related to modern rice and bamboo.
The appearance of mountains in the western United States during the Miocene and Pliocene epochs, a period of some 25 million years, created a continental climate favorable to the evolution of grasslands. Existing forest biomes declined, and grasslands became much more widespread. Following the Pleistocene Ice Ages, grasslands expanded in range in the hotter, drier climates, and began to become the dominant land feature worldwide.
Grasslands often occur in areas with annual precipitation between 600 mm (24 in) and 1,500 mm (59 in) and average mean annual temperatures ranges from −5 and 20 °C (Woodward et al. 2004). However, some grasslands occur in colder(-20°C) and hotter(30°C) climatic conditions. Grassland can exist in habitats that are frequently disturbed by grazing or fire, as such disturbance prevents the encroachment of woody species. Species richness is particularly high in grasslands of low soil fertility such as serpentine barrens and calcareous grasslands. Infertility may also prevent woody encroachment as low nutrient levels in the soil may inhibit the growth of forest and shrub species.most plants from growing. Temperate grasslands occur in temperate climates typified by distinct seasonality (warm summers and cold winters).
Grasslands dominated by unsown wild-plant communities ("unimproved grasslands") can be called either natural or 'semi-natural' habitats. The majority of grasslands in temperate climates are 'semi-natural'. Although their plant communities are natural, their maintenance depends upon anthropogenic activities such as low-intensity farming, which maintains these grasslands through grazing and cutting regimes. These grasslands contain many species of wild plants – grasses, sedges, rushes and herbs – 25 or more speerican prairie grasslands or lowland wildflower meadows in the UK are now rare and their associated wild flora equally threatened. Associated with the wild-plant diversity of the "unimproved" grasslands is usually a rich invertebrate fauna; also there are many species of birds that are grassland "specialists", such as the snipe and the Great Bustard. Agriculturally improved grasslands, which dominate modern intensive agricultural landscapes, are usually poor in wild plant species due to the original diversity of plants having been destroyed by cultivation, the original wild-plant communities having been replaced by sown monocultures of cultivated varieties of grasses and clovers, such as Perennial ryegrass and White Clover. In many parts of the world "unimproved" grasslands are one of the least threatened habitats, and a target for acquisition by wildlife conservation groups or for special grants to landowners who are encouraged to manage them appropriately.
Grasslands are of vital importance for raising livestock for human consumption and for milk and other dairy products.
Grassland vegetation remains dominant in a particular area usually due to grazing, cutting, or natural or manmade fires, all discouraging colonisation by and survival of tree and shrub seedlings. Some of the world's largest expanses of grassland are found in African savanna, and these are maintained by wild herbivores as well as by nomadic pastoralists and their cattle, sheep or goats.
Grasslands may occur naturally or as the result of human activity. Grasslands created and maintained by human activity are called anthropogenic grasslands. Hunting peoples around the world often set regular fires to maintain and extend grasslands, and prevent fire-intolerant trees and shrubs from taking hold. The tallgrass prairies in the US Midwest may have been extended eastward into Illinois, Indiana, and Ohio by human agency. Much grassland in northwest Europe developed after the Neolithic Period, when people gradually cleared the forest to create areas for raising their livestock.
These grasslands are classified with tropical and subtropical savannas and shrublands as the tropical and subtropical grasslands, savannas, and shrublands biome. Notable tropical and subtropical grasslands include the Llanos grasslands of northern South America.
Mid-latitude grasslands, including the Prairie and Pacific Grasslands of North America, the Pampas of Argentina, Brazil and Uruguay, calcareous downland, and the steppes of Europe. They are classified with temperate savannas and shrublands as the temperate grasslands, savannas, and shrublands biome. Temperate grasslands are the home to many large herbivores, such as bison, gazelles, zebras, rhinoceroses, and wild horses. Carnivores like lions, wolves and cheetahs and leopards are also found in temperate grasslands. Other animals of this region include: deer, prairie dogs, mice, jack rabbits, skunks, coyotes, snakes, fox, owls, badgers, blackbirds (both Old and New World varieties), grasshoppers, meadowlarks, sparrows, quails, hawks and hyenas.
Grasslands that are flooded seasonally or year-round, like the Everglades of Florida, the Pantanal of Brazil, Bolivia and Paraguay or the Esteros del Ibera in Argentina.They are classified with flooded savannas as the flooded grasslands and savannas biome and occur mostly in the tropics and subtropics.
Watermeadows are grasslands that are deliberately flooded for short periods.
High-altitude grasslands located on high mountain ranges around the world, like the Páramo of the Andes Mountains. They are part of the montane grasslands and shrublands biome and also constitute tundra.
Similar to montane grasslands, polar arctic tundra can have grasses, but high soil moisture means that few tundras are grass-dominated today. However, during the Pleistocene ice ages, a polar grassland known as steppe-tundra occupied large areas of the Northern hemisphere. These are in the tundra biome.
Also called desert grasslands, this is composed of sparse grassland ecoregions located in the deserts and xeric shrublands biome.
Mites, insect larvae, nematodes and earthworms inhabit deep soil, which can reach 6 metres (20 ft) underground in undisturbed grasslands on the richest soils of the world. These invertebrates, along with symbiotic fungi, extend the root systems, break apart hard soil, enrich it with urea and other natural fertilizers, trap minerals and water and promote growth. Some types of fungi make the plants more resistant to insect and microbial attacks.
Grassland in all its form supports a vast variety of mammals, reptiles, birds, and insects. Typical large mammals include the Blue Wildebeest, American Bison, Giant Anteater and Przewalski's Horse.
While grasslands in general support diverse wildlife, given the lack of hiding places for predators, the African savanna regions support a much greater diversity in wildlife than do temperate grasslands.
There is evidence for grassland being much the product of animal behaviour and movement; some examples include migratory herds of antelope trampling vegetation and African Bush Elephants eating Acacia saplings before the plant has a chance to grow into a mature tree.
A wet meadow is a semi-wetland meadow which is saturated with water throughout much of the year. Some experts][ consider a wet meadow to be a kind of marsh, while others consider it to be a distinct type of wetland. Wet prairies and wet savannas are similar. Wet meadows may occur because of restricted drainage or the receipt of large amounts of water from rain or melted snow. They may also occur in riparian zones and around the shores of large lakes.
Unlike a marsh or swamp, a wet meadow does not have standing water present except for brief to moderate periods during the growing season. Instead, the ground in a wet meadow fluctuates between brief periods of flooding and longer periods of wetness. Wet meadows often have large numbers of wetland plant species, which frequently survive as buried seeds during dry periods, and then regenerate after flooding. Wet meadows therefore do not usually support aquatic life such as fish. They typically have a high diversity of plant species, and may attract large numbers of birds, small mammals and insects including butterflies.
Vegetation in a wet meadow usually includes a wide variety of herbaceous species including sedges, rushes, grasses and a wide diversity of other plant species. A few of many possible examples include species of Rhexia, Parnassia, Lobelia, many species of wild orchids (e.g. Calopogon and Spiranthes), and carnivorous plants such as Sarracenia and Drosera. Woody plants if present, account for a minority of the total area cover. High water levels are one of the important factors that prevent invasion by woody plants; in other cases, fire is important. In areas with low frequencies of fire, or reduced water level fluctuations, or higher fertility, plant diversity will decline.
Wet meadows were once common in wetland types around the world. They remain an important community type in wet savannas and flatwoods. The also survive along rivers and lakeshores where water levels are allowed to change within and among years. But their area has been dramatically reduced. In some areas, wet meadows are partially drained and farmed and therefore lack the biodiversity described here. In other cases, the construction of dams has interfered with the natural fluctuation of water levels that generates wet meadows.
The most important factors in creating and maintaining wet meadows are therefore natural water level fluctuations and recurring fire. In some cases, small areas of wet meadow are artificially created. Due to the concern with damage that excessive stormwater runoff can cause to nearby lakes and streams, artificial wetlands can be created to capture stormwater. Often this produce marshes, but in some cases wet meadows may be produced. The idea is to capture and store rainwater onsite and use it as a resource to grow attractive native plants that thrive in such conditions. The Buhr Park Children's Wet Meadow is one such project. It is a group of wet meadow ecosystems in Ann Arbor, Michigan designed as an educational opportunity for school-age children. In Europe, wet meadows are sometimes managed by hay-cutting and grazing.
See Taxonomy section.
Atomarchus, Chilopoma, Coluber, Eutaenia, Eutainia, Leptophis, Natrix, Nerodia, Phamnovis, Prymnomiodon, Stypocemus, Tropidonote, Tropidonotus, Vipera
The garter snake is a colubrid snake genus (Thamnophis) common across North America, ranging from the Alaskan Panhandle to Central America. It is the single most widely distributed genus of reptiles in North America][. The garter snake is also the Massachusetts state reptile.
With no real consensus on the classification of species of Thamnophis, disagreement among taxonomists and sources, such as field guides, over whether two types of snakes are separate species or subspecies of the same species is common.][ They are also closely related to the snakes of the genus Nerodia, and some species have been moved back and forth between genera.
Garter snakes spread throughout North America. The common garter snake (Thamnophis sirtalis) is the only species of snake to be found in Alaska, and is one of the northernmost species of snake in the world, possibly second only to the crossed viper, Vipera berus. The genus is as far ranging due to its less discriminant diet and adaptability to different biomes and landforms, with varying proximity to water. However, in the western part of North America, these snakes are more aquatic than in the eastern portion. Northern populations hibernate in larger groups than southern ones.
Despite the decline in their population from collection as pets (especially in the more northerly regions in which large groups are collected at hibernation)][, pollution of aquatic areas, and introduction of bullfrogs as potential predators, garter snakes are still some of the most commonly found reptiles in much of their ranges. The San Francisco garter snake (Thamnophis sirtalis tetrataenia), however, is an endangered subspecies and has been on the endangered list since 1969. Predation by crawfish has also been responsible for the decline of the narrow-headed garter snake (Thamnophis rufipunctatus).][
Garter snakes, like all snakes, are carnivorous. Their diets consist of almost any creature they are capable of overpowering: slugs, earthworms, leeches, lizards, amphibians, ants, crickets, frog eggs, toads, and rodents. When living near water, they will eat other aquatic animals. The ribbon snake (Thamnophis sauritus) in particular favors frogs (including tadpoles), readily eating them despite their strong chemical defenses. Food is swallowed whole. Garter snakes often adapt to eating whatever they can find, and whenever, because food can be scarce or abundant. Although they feed mostly upon live animals, they will sometimes eat eggs.
Garter snakes have complex systems of pheromonal communication. They can find other snakes by following their pheromone-scented trails. Male and female skin pheromones are so different as to be immediately distinguishable. However, male garter snakes sometimes produce both male and female pheromones. During mating season, this ability fools other males into attempting to mate with them. This causes the transfer of heat to them in kleptothermy, which is an advantage immediately after hibernation, allowing them to become more active. Male snakes giving off both male and female pheromones have been shown to garner more copulations than normal males in the mating balls that form at the den when females enter the mating melee.
If disturbed, a garter snake may coil and strike, but typically it will hide its head and flail its tail. These snakes will also discharge a malodorous, musky-scented secretion from a gland near the cloaca. They often use these techniques to escape when ensnared by a predator. They will also slither into the water to escape a predator on land. Hawks, crows, raccoons, crayfish, and other snake species (such as the coral snake and king snake) will eat garter snakes, with even shrews and frogs eating the juveniles.
Being heterothermic, like all reptiles, garter snakes bask in the sun to regulate their body temperature. During hibernation, garter snakes typically occupy large, communal sites called hibernacula. These snakes will migrate large distances to brumate.
Garter snakes go into brumation before they mate. They stop eating for about two weeks beforehand to clear their stomachs of any food that would rot there otherwise. Garter snakes begin mating as soon as they emerge from brumation. During mating season, the males mate with several females. In chillier parts of their range, male common garter snakes awaken from brumation first, giving themselves enough time to prepare to mate with females when they finally appear. Males come out of their dens and, as soon as the females begin coming out, surround them. Female garter snakes produce a sex-specific pheromone that attracts male snakes in droves, sometimes leading to intense male-male competition and the formation of mating balls of up to 25 males per female. After copulation, a female leaves the den/mating area to find food and a place to give birth. Female garter snakes are able to store the male's sperm for years before fertilization. The young are incubated in the lower abdomen, at about the midpoint of the length of the female's body. Garter snakes are ovoviviparous, meaning they give birth to live young. However, this is different from being truly viviparous, which is seen in mammals. Gestation is two to three months in most species. As few as three or as many as 80 snakes are born in a single litter. The young are independent upon birth. On record, the greatest number of garter snakes reported to be born in a single litter is 98.
Baby garter snakes shed their first skin almost immediately, and will begin eating soon after. The first shedding is very fine and often disintegrates in minutes under the slithering masses of new snakes. Feeding baby garter snakes can be tricky; most often meal worms, lizards and tadpoles (thawed fully and waved before the snake) will entice appetites. A few weeks may pass before a baby garter snake eats; it takes them some time to become accustomed to new settings.
Garter snakes were long thought to be nonvenomous, but recent discoveries have revealed they do, in fact, produce a mild neurotoxic venom. Garter snakes cannot kill humans with the small amounts of comparatively mild venom they produce, and they also lack an effective means of delivering it. They do have enlarged teeth in the back of their mouths, but their gums are significantly larger. The Duvernoy's glands of garters are posterior (to the rear) of the snake's eyes. The mild venom is spread into wounds through a chewing action.
Southern ribbon snake (Thamnophis sauritus sackeni) is a species of garter snake. It is one of four subspecies of the eastern ribbon snake (Thamnophis sauritus) is smaller than the other Thamnophis sauritus subspecies at 16 to 30 inches and occurs in the southeastern United States from South Carolina, extreme southern Georgia and Alabama, southeast Mississippi and all of Florida at sea level to 500 feet.
The color is greenish olive, or blackish in old specimens. It has a dorsal stripe that is vetiver green or light olive-gray bordered on either side with black and lateral stripes are marguerite yellow.
The Southern ribbon is found in marshes, lakes, ponds, and shores of streams. It is semi-aquatic and semi-arboreal with wet meadows and thicket a favorite habitat.
See Taxonomy section.
Atomarchus, Chilopoma, Coluber, Eutaenia, Eutainia, Leptophis, Natrix, Nerodia, Phamnovis, Prymnomiodon, Stypocemus, Tropidonote, Tropidonotus, Vipera Wetland
Wyoming is home to 12 amphibian species and 22 species of reptiles.
The Tiger Salamander (Ambystoma tigrinum) is a species of Mole Salamander. Tiger salamanders are large, with a typical length of 6–8 inches. They can reach up to 14 inches in length, particularly neotenic individuals. Adults are usually blotchy with grey, green, or black, and have large, lidded eyes. They have short snouts, thick necks, sturdy legs, and long tails. Their diet consists largely of small insects and worms, though it is not rare for an adult to consume small frogs and baby mice. Thamnophis
13 sspp., see text
The Common Garter Snake (Thamnophis sirtalis) is an indigenous North American snake found widely across the continent. Most garter snakes have a pattern of yellow stripes on a brown or green background and their average length is about 55 cm (22 in), with a maximum length of about 137 cm (54 in). The average body mass is 150 g (5.3 oz). Environment