Hamilton Disston
Hamilton Disston, was an industrialist and real-estate developer who purchased four million acres of Florida land in 1881, an area larger than the state of Connecticut, the most land purchased by a single person in world history. Disston was the son of Pennsylvania-based industrialist Henry Disston who formed Disston & Sons Saw Works, which Hamilton ran and, one of the largest saw manufacturing companies in the world. Hamilton Disston's investment in the infrastructure of Florida spurred growth throughout the state, his related efforts to drain the Everglades triggered the state's first land boom with numerous towns and cities established through the area. Disston's land purchase and investments were directly responsible for creating or fostering the towns of Kissimmee, St. Cloud, Tarpon Springs, indirectly aided the rapid growth of St. Petersburg, Florida, he furthermore oversaw the successful cultivation of sugarcane near the Kissimmee area. Although Disston's engineered canals aided water transport and steamboat traffic in Florida, he was unsuccessful in draining the Kissimmee River floodplain or lowering the surface water around Lake Okeechobee and in the Everglades.
He was forced to sell much of his investments at a fraction of their original costs. However, his land purchase primed Florida's economy and allowed railroad magnates Henry Flagler and Henry Plant to build rail lines down the east coast of Florida, another joining the west coast, which directly led to the domination of the tourist and citrus industries in Florida. Disston's immediate impact was in the Philadelphia area, where he was active in Republican politics and a philanthropist, but his legacy is associated with the draining and development of Florida. Hamilton Disston was born in Philadelphia, the eldest son of nine children born to Mary Steelman and Henry Disston, an English immigrant and descendant of French nobility. Disston's father was a successful industrialist who rose from being orphaned just days after arriving in the United States to running the Keystone Saw Works when Hamilton was a child. Henry Disston was responsible for multiple machining and saw patents, in the spirit of Victorian-era paternalism and engineered a community around his steel factory in Tacony, Pennsylvania.
After attending public school, Hamilton left at 15 years old, opting for an apprenticeship at the saw factory which, by that time, was a $500,000-per-year international venture. His father threatened to fire him for leaving the factory to work for a volunteer fire department. Hamilton twice joined the Union Army only to have Henry purchase his release, but Hamilton organized a Company of saw factory employees during the Gettysburg Campaign. Henry agreed to support the "Disston Volunteers" financially. After the American Civil War, Disston returned to work in his father's factory as an executive. In 1878, following the death of Henry Disston and his brothers Horace and Jacob inherited the company, renamed to Henry Disston & Sons. Hamilton became the controlling member of the 2,000-employee company and expanded production to 1.4 million hacksaws and three million files per year. Only a month after Henry's death, Hamilton gave President Rutherford B. Hayes a tour of the factory where an unshaped piece of steel was manufactured into a 26-inch hand saw in only 42 minutes, was presented to the president at the end of the tour—etched with his name.
While the saw manufacturing business continued growing, Disston branched out, investing in a chemical firm, a Chinese railroad, real estate in Atlantic City, New Jersey and mining in the western United States. In the 1840s and 1850s, the sparsely populated state of Florida came to own 15,000,000 acres of swamp land, granted by the U. S. Congress to states with wetlands for the purpose of reclaiming the land under water by constructing canals and levees. In Florida, consolidated grants for the purpose of building rail infrastructure and reclaiming wetlands were placed in a trust called the Internal Improvement Fund of the State of Florida; the trust fund was managed by the Governor of four state officials. The fund pledged land to railroad companies and guaranteed bonds issued by the railroad companies on the land; when the high costs associated with the American Civil War and Reconstruction caused railroad companies to default on the bonds, the fund became liable and sank into debt and into Federal Court receivership.
By the time Governor George Franklin Drew took office in 1877, the fund was nearly $1 million in debt. The state constitution forbade issuing bonds to repay it. In 1877, diplomat Henry Shelton Sanford invited Disston, an avid sport fisherman, on a fishing trip through Florida. During the trip, Disston realized the possibility that enormous tracts of land could be reclaimed for agriculture by using canals to drain Florida's Lake Okeechobee. An application for foreclosure of the IIF and its land was filed in federal court in 1880. Negotiations to relieve the debt were held with various potential investors, including Sanford and Alexander St. Clair-Abrams, but did not come to fruition. Disston and five associates, entered into a land reclamation contract with the Internal Improvement Fund in January 1881; the contract stipulated that Disston and associates would be deeded half of whatever land his Atlantic and Gulf Coast Canal and Okeechobee Land Company reclaimed around Lake Okeechobee, the Kissimmee and Miami Rivers.
Congressman and Disston family friend, William
Geography and ecology of the Everglades
The geography and ecology of the Everglades involve the complex elements affecting the natural environment throughout the southern region of the U. S. state of Florida. Before drainage, the Everglades were an interwoven mesh of marshes and prairies covering 4,000 square miles; the Everglades is a vast watershed that has extended from Lake Okeechobee 100 miles south to Florida Bay, many interconnected ecosystems within a geographic boundary. It is such a unique meeting of water and climate that the use of either singular or plural to refer to the Everglades is appropriate; when Marjory Stoneman Douglas wrote her definitive description of the region in 1947, she used the metaphor "River of Grass" to explain the blending of water and plant life. Although sawgrass and sloughs are the enduring geographical icons of the Everglades, other ecosystems are just as vital, the borders marking them are subtle or nonexistent. Pinelands and tropical hardwood hammocks are located throughout the sloughs; the oldest and tallest trees are cypresses, whose roots are specially adapted to grow underwater for months at a time.
The Big Cypress Swamp is well known for its 500-year-old cypresses, though cypress domes can appear throughout the Everglades. As the fresh water from Lake Okeechobee makes its way to Florida Bay, it meets salt water from the Gulf of Mexico; the marine environment of Florida Bay is considered part of the Everglades because its sea grasses and aquatic life are attracted to the constant discharge of fresh water. These ecological systems are always changing due to environmental factors. Geographic features such as the Western Flatwoods, Eastern Flatwoods, the Atlantic Coastal Ridge affect drainage patterns. Geologic elements and the frequency of storms and fire are formative processes for the Everglades, they help to sustain and transform the ecosystems in the Shark River Valley, Big Cypress Swamp, coastal areas and mangrove forests. Ecosystems have been described as both resilient. Minor fluctuations in water levels have far-reaching consequences for many plant and animal species, the system cycles and pulses with each change.
At only 5,000 years of age, the Everglades is a young region in geological terms. Its ecosystems are in constant flux as a result of the interplay of three factors: the type and amount of water present, the geology of the region, the frequency and severity of fires. Water is the dominant element in the Everglades, it shapes the land and animal life of South Florida; the South Florida climate was once semi-arid, interspersed with wet periods. Between 10,000 and 20,000 years ago, sea levels rose, submerging portions of the Florida peninsula and causing the water table to rise. Fresh water saturated the limestone, creating springs and sinkholes; the abundance of fresh water allowed new vegetation to take root, through evaporation formed thunderstorms. Limestone was dissolved by the acidic rainwater; the limestone wore away, groundwater came into contact with the surface, creating a massive wetland ecosystem. Although the region appears flat, the wearing away of the limestone in some areas created slight valleys and plateaus—a difference of inches in elevation—that affected not only the flow of water, but types of vegetation present.
The Everglades are unique. Before the first attempt at draining the Everglades in 1882, the entire watershed extended from Orlando to Florida Bay comprising the Kissimmee–Lake Okeechobee–Everglades watershed. Kissimmee River outlets flow into Lake Okeechobee. Only two seasons exist in the Everglades: dry. Average annual rainfall in the Everglades is 62 inches, though fluctuations of precipitation are normal. Droughts and tropical storms are normal occurrences in the area; when Lake Okeechobee exceeds its water storage capacity during the wet season, it pours over the southern rim and flows for 100 miles to Florida Bay. The gradient change is so slight. Sawgrass thrives in this river, dominates freshwater marshes and sloughs, is the main characteristic of the region. Severe weather, in the form of tropical storms and hurricanes affects the structure of the Everglades. Between 1871 and 2003, 40 tropical cyclones struck the Everglades every one to three years; these storms alter the coastline, flush decaying vegetation from estuaries, strip weakened branches from trees, disperse seeds and plant material.
Hurricane Donna in 1960 affected 120 square miles of mangrove forests by depositing marl over the roots and depriving the trees of oxygen. It eradicated orchids and other epiphytes that once flourished in the mangroves. Donna significantly spread buttonwood and glasswort, epiphytes began to grow in new areas. Although the lasting effects remain to be seen, Hurricane Andrew in 1992 destroyed mangrove forests and snapped slash pines in half. However, regrowth occurred and sand deposited by the storm surge improved nesting conditions for crocodiles and sea turtles. A vast marshland could only have been formed due to the underlying rock formations in southern Florida; the floor of
Carolina anole
The Green anole is an arboreal anole lizard native to the southeastern United States and introduced elsewhere. Other common names include the American green anole, American anole, red-throated anole, it is sometimes referred to as the American chameleon due to its ability to change color from several brown hues to bright green, its somewhat similar appearance and diet preferences. However it is not a true chameleon and the nickname is misleading although it can camouflage; the green anole is a small to medium-sized lizard, with a slender body. The head is long and pointed with ridges between the eyes and nostrils, smaller ones on the top of the head; the toes have adhesive pads to facilitate climbing. They exhibit the males being fifteen percent larger; the male dewlap is three times the size of the female's and bright red, whereas that of the female is lighter in color, ranging from white to pale pink. Males can extend a pronounced dorsal ridge behind the head when under stress. Females have a prominent white stripe running along a feature most males lack.
Adult males are 12.5–20.3 cm long, with about 60-70% of, made up of its tail, with a body length up to 7.5 cm and can weigh from 3–7 g. Colour varies from brown to green and can be changed like many other kinds of lizards, but anoles are related to iguanas and are not true chameleons. Although A. carolinensis is sometimes called an'American chameleon', true chameleons do not occur in the Americas, A. carolinensis is not the only lizard in its area of distribution capable of changing colour. In contrast, many species of true chameleons display a greater range of color adaptation, though some can hardly change color at all; the typical coloration for a green anole ranges from the richest and brightest of greens to the darkest of browns, with little variation in between. The color spectrum is a result of three layers of pigment cells or chromatophores: the xanthophores, responsible for the yellow pigmentation; the anole changes its color depending on mood, level of stress, activity level and as a social signal.
Although claimed, evidence does not support that they do it in response to the color of the background. Whether they do it in response to temperature is less clear, with studies both supporting it and contradicting it. Changing color while under a contrasting shadow can cause a "stencil effect", where the outline of the shadow is temporarily imprinted in the animal's coloration; when stressed—while fighting, for example—the skin behind the lizard's eyes may turn black independently from the rest of the animal's coloration, forming "postocular spots." A lack in one of the pigment genes causes color exceptions. These color mutations are called phases; the rare blue-phased green anole lacks xanthophores, which results in a blue, rather than red pastel blue, anole. These specimens have become popular in the pet trade market; when the anole is lacking xanthophores, it is said to be axanthic and the animal will have a pastel- or baby-blue hue. They are rare—usually produced in one of every 20,000 individual anoles in the wild.
Another phase is the yellow-phased green anole. Colonies of these rare color-phased anoles have been reported, but anoles with these color mutations live for long, since the green color provides camouflage for hunting down prey, as well as hiding from predators. Anolis carolinensis is a species of the large lizard genus Anolis within the family Dactyloidae. Within the genus, thirteen species have been identified as a distinct clade, referred to as the Anolis carolinensis series of anoles; this group are mid-sized trunk crown anoles with large conspicuously elongated heads and extreme levels of sexual dimorphism. The species was named by Friedrich Siegmund Voigt in 1832. Two subspecies are accepted, Anolis carolinensis carolinensis and Anolis carolinensis seminolus, found in the northern and southern reaches of the species distribution and hence are known as the northern and southern green anoles; this species is native to North America, where it is found in the subtropical southeastern parts of the continent.
Anoles are most abundant on the Atlantic Coastal Plains in North Carolina, South Carolina and Florida, on the Gulf Coast in Alabama, Mississippi and Texas, where they extend inland as far as Texas Hill Country. In the Carolinas they are found in the coastal plains and southern piedmont of North Carolina, but throughout South Carolina, while in Georgia they are widespread except in the Blue Ridge region; the species has been introduced into the Ogasawara Islands. They have been sighted in Orange County and San Diego County of southern California, with sightings in San Diego going at least as far back as 1993. A. Carolinensis is arboreal in nature but may be seen on the ground and seen on shrubs in the low country of the Carolinas, but is a common sight in urban areas on steps and railings, adjacent to foliage, it is common on roadsides, the edges of forests where there are shrubs and vines, but building sites having abundant foliage and sunlight. Their preferred habitat is brushy clearings. Green anole males that encounter rival males find it is an introduced and invasive brown anole
Alligatoridae
The family Alligatoridae of crocodylians includes alligators and caimans. The superfamily Alligatoroidea includes all crocodilians that are more related to the American alligator than to either the Nile crocodile or the gharial. Members of this superfamily first arose in the late Cretaceous. Leidyosuchus of Alberta is the earliest known genus. Fossil alligatoroids have been found throughout Eurasia as land bridges across both the North Atlantic and the Bering Strait have connected North America to Eurasia during the Cretaceous and Neogene periods. Alligators and caimans split in North America during the late Cretaceous and the latter reached South America by the Paleogene, before the closure of the Isthmus of Panama during the Neogene period; the Chinese alligator descended from a lineage that crossed the Bering land bridge during the Neogene. The modern American alligator is well represented in the fossil record of the Pleistocene; the alligator's full mitochondrial genome was sequenced in the 1990s and it suggests the animal evolved at a rate similar to mammals and greater than birds and most cold-blooded vertebrates.
The full genome, published in 2014, suggests that the alligator evolved much more than mammals and birds. The lineage including alligators proper occurs in the fluvial deposits of the age of the Upper Chalk in Europe, where they did not die out until the Pliocene age; the true alligators are today represented by two species, A. mississippiensis in the southeastern United States, which can grow to 15 ft and weigh 1000 lbs and the small A. sinensis in the Yangtze River, which grows to an average of 5 ft. Their name derives from the Spanish el lagarto, which means "the lizard". In Central and South America, the alligator family is represented by six species of the subfamily Caimaninae, which differ from the alligator by the absence of a bony septum between the nostrils, having ventral armour composed of overlapping bony scutes, each of, formed of two parts united by a suture. Besides the three species in Caiman, the smooth-fronted caimans in genus Paleosuchus and the black caiman in Melanosuchus are described.
Caimans tend to be more agile and crocodile-like in their movements, have longer, sharper teeth than alligators. C. Crocodilus, the spectacled caiman, has the widest distribution, from southern Mexico to the northern half of Argentina, grows to a modest size of about 2.2 m. The largest is the near-threatened Melanosuchus niger, the jacare-assu or large or black caiman of the Amazon River basin. Black caimans grow with the largest recorded size 5.79 m. The black caiman and American alligator are the only members of the alligator family that pose the same danger to humans as the larger species of the crocodile family. Although caimans have not been studied in depth, scientists have learned their mating cycles are linked to the rainfall cycles and the river levels, which increases chances of survival for their offspring. Alligators differ from crocodiles principally in having wider and shorter heads, with more obtuse snouts. In general, crocodiles tend to be more dangerous to humans than alligators.
Another discovered trait is that of both caimans and American alligators partaking of foliage and fruit in addition to their normal diet of fish and meat. Superfamily Alligatoroidea Family Alligatoridae Subfamily Alligatorinae Genus † Albertochampsa Genus Alligator † Alligator mcgrewi † Alligator mefferdi American alligator, Alligator mississippiensis † Alligator olseni † Alligator prenasalis Chinese alligator, Alligator sinensis Genus † Allognathosuchus Genus † Arambourgia Genus † Ceratosuchus Genus † Chrysochampsa Genus † Eoalligator Genus † Hassiacosuchus Genus † Hispanochampsa Genus † Krabisuchus Genus † Navajosuchus Genus † Procaimanoidea Genus † Wannaganosuchus Subfamily Caimaninae Genus Caiman Yacare caiman, Caiman yacare Spectacled caiman, Caiman crocodilus Rio Apaporis caiman, C. c. apaporiensis Brown caiman, C. c. fuscus Broad-snouted caiman, Caiman latirostris † Caiman lutescans Genus Melanosuchus † Melanosuchus fisheri Black caiman, Melanosuchus niger Genus † Eocaiman Genus † Mourasuchus Genus † Necrosuchus Genus † Orthogenysuchus Genus Paleosuchus Cuvier's dwarf caiman, Paleosuchus palpebrosus Smooth-fronted caiman, Paleosuchus trigonatus Genus † Purussaurus "Crocodilians: Natural History & Conservation" crocodilian.com "Family Alligatoridae Gray 1844", fossilworks.org.
Media related to Alligatoridae at Wikimedia Commons Data related to Alligatoridae at Wikispecies
Big Cypress National Preserve
Big Cypress National Preserve is a United States National Preserve located in South Florida, about 45 miles west of Miami on the Atlantic coastal plain. The 720,000-acre Big Cypress, along with Big Thicket National Preserve in Texas, became the first national preserves in the United States National Park System when they were established on October 11, 1974. In 2008, Florida film producer Elam Stoltzfus featured the preserve in a PBS documentary. Big Cypress borders the wet freshwater marl prairies of Everglades National Park to the south, other state and federally protected cypress country in the west, with water from the Big Cypress flowing south and west into the coastal Ten Thousand Islands region of Everglades National Park; when Everglades National Park was established in 1947, Big Cypress was intended to be included. Big Cypress has a tropical savannah climate. Days are some of the hottest in Florida. January has an average high of 78.4 °F and August has an average high of 94.0 °F, while Miami averages 76.1 and 90.7 °F, respectively.
However, nights cool down into the 50s °F in winter. Means range from 66.5 °F in January to 84.7 °F in August. Highs exceed 90 °F on 159 days per year, while they fall below 70 °F on just 10. Hardiness zone is 10A, with an average annual minimum of 34 °F; the lowest recorded daily high was 48 °F in 2010, while the highest low on record was 89 °F in 2005. Ecologically, the preserve is more elevated than the western Everglades. Big Cypress was occupied by various cultures of Native Americans, their descendants include the federally recognized Miccosukee Tribe of Indians of Florida and the Seminole Tribe of Florida. Early European-American settlers hunted herons and egrets, whose feathers were popular with 19th and 20th century hat-makers in New York and Paris. Poachers hunted American crocodiles to near extinction; when the timber industry began to operate in the area, it built railroads, cut and hauled out most of the cypress ecosystem's old growth trees. Portions of the Big Cypress were farmed for winter vegetables.
The search for oil in Florida began in 1901 with no success. After 80 more dry holes had been drilled throughout the state, on September 26, 1943, Humble Oil Company discovered Florida's first producing oil well in the northwest portion of what is now Big Cypress National Preserve. Big Cypress National Preserve differs from Everglades National Park in that, when it was established by law in 1974, the Miccosukee and Traditional people were provided with permanent rights to occupy and use the land in traditional ways, they and other hunters may use off-road vehicles, home and business owners have been permitted to keep their properties in the preserve. As in Everglades National Park, petroleum exploration was permitted within Big Cypress in the authorizing legislation, but plans are under way for the government to buy out the remaining petroleum leases in order to shut down non-governmental commercial access to the environment. In the 1960s, Native Americans and conservationists succeeded at fighting an effort to move Miami International Airport's international flights to a new airport in the Big Cypress area.
They followed up with a campaign to have Big Cypress included in the National Parks System. Although construction of the new airport had begun, it was stopped after one runway was completed, it is now known as the Dade-Collier Transition Airport. The preserve is diverse biologically. Dominated by a wet cypress forest, it is host to an array of flora and fauna, including mangroves, alligators, venomous snakes like the cottonmouth and eastern diamondback rattlesnake, a variety of birds, river otter, coyote, black bear and cougar; the preserve is home to federally listed endangered species including, the eastern indigo snake, the Florida sandhill crane. Twelve campgrounds in Big Cypress are tailored to motor vehicles, where tourists planning overnight stays can park their vehicles and off-road vehicles in designated areas; the southern terminus of the Florida National Scenic Trail is located in Big Cypress, provides hiking opportunities during the winter months. Hiking throughout Big Cypress is enjoyable in all seasons, with most of the cypress country more hospitable to hikers than the dense sawgrass prairies of the central Everglades.
Some of the most beautiful wading and walking can be found in cypress strands and prairies between the Loop Road and the Tamiami Trail. Wildlife is abundant in the preserve. Most notable and seen, the American Alligators can be up to around 12 feet in length. Another notable and endangered animal, the Florida Panther calls the Preserve home. Though both relatively timid, wading through the cypress country requires constant alertness. Before going out, visit one of the preserve's visitor centers for information on the current conditions and local trails; the visitor centers offer an educational video about the surroundings viewable on the Big Cypress YouTube channel. Rangers lead swamp walk hikes in the dry winter months, as well as canoe trips, boardwalk talks. Hunting is a long-established recreational activity in the area and is protected in the designation of the area as a Preserve
Marsh
A marsh is a wetland, dominated by herbaceous rather than woody plant species. Marshes can be found at the edges of lakes and streams, where they form a transition between the aquatic and terrestrial ecosystems, they are dominated by grasses, rushes or reeds. If woody plants are present they tend to be low-growing shrubs; this form of vegetation is what differentiates marshes from other types of wetland such as swamps, which are dominated by trees, mires, which are wetlands that have accumulated deposits of acidic peat. Marshes provide a habitat for many species of plants and insects that have adapted to living in flooded conditions; the plants must be able to survive in wet mud with low oxygen levels. Many of these plants therefore have aerenchyma, channels within the stem that allow air to move from the leaves into the rooting zone. Marsh plants tend to have rhizomes for underground storage and reproduction. Familiar examples include cattails, sedges and sawgrass. Aquatic animals, from fish to salamanders, are able to live with a low amount of oxygen in the water.
Some can obtain oxygen from the air instead, while others can live indefinitely in conditions of low oxygen. Marshes provide habitats for many kinds of invertebrates, amphibians and aquatic mammals. Marshes have high levels of biological production, some of the highest in the world, therefore are important in supporting fisheries. Marshes improve water quality by acting as a sink to filter pollutants and sediment from the water that flows through them. Marshes are able to absorb water during periods of heavy rainfall and release it into waterways and therefore reduce the magnitude of flooding; the pH in marshes tends to be neutral to alkaline, as opposed to bogs, where peat accumulates under more acid conditions. Marshes differ depending on their location and salinity. Both of these factors influence the range and scope of animal and plant life that can survive and reproduce in these environments; the three main types of marsh are salt marshes, freshwater tidal marshes, freshwater marshes. These three can be found worldwide and each contains a different set of organisms.
Saltwater marshes are found around the world in mid to high latitudes, wherever there are sections of protected coastline. They are located close enough to the shoreline that the motion of the tides affects them, sporadically, they are covered with water, they flourish where the rate of sediment buildup is greater than the rate at which the land level is sinking. Salt marshes are dominated by specially adapted rooted vegetation salt-tolerant grasses. Salt marshes are most found in lagoons, on the sheltered side of shingle or sandspit; the currents there carry the fine particles around to the quiet side of the spit and sediment begins to build up. These locations allow the marshes to absorb the excess nutrients from the water running through them before they reach the oceans and estuaries; these marshes are declining. Coastal development and urban sprawl has caused significant loss of these essential habitats. Although considered a freshwater marsh, this form of marsh is affected by the ocean tides.
However, without the stresses of salinity at work in its saltwater counterpart, the diversity of the plants and animals that live in and use freshwater tidal marshes is much higher than in salt marshes. The most serious threats to this form of marsh are the increasing size and pollution of the cities surrounding them. Ranging in both size and geographic location, freshwater marshes make up the most common form of wetland in North America, they are the most diverse of the three types of marsh. Some examples of freshwater marsh types in North America are: Wet meadows occur in areas such as shallow lake basins, low-lying depressions, the land between shallow marshes and upland areas, they occur on the edges of large lakes and rivers. Wet meadows have high plant diversity and high densities of buried seeds, they are flooded but are dry in the summer. Vernal pools are a type of marsh found only seasonally in shallow depressions in the land, they can be covered in shallow water, but in the summer and fall, they can be dry.
In western North America, vernal pools tend to form in open grasslands, whereas in the east they occur in forested landscapes. Further south, vernal pools form in pine flatwoods. Many amphibian species depend upon vernal pools for spring breeding. An example is the endangered gopher frog. Similar temporary ponds occur in other world ecosystems. However, the term vernal pool can be applied to all such temporary pool ecosystems. Playa lakes are a form of shallow freshwater marsh that occurs in the southern high plains of the United States. Like vernal pools, they are only present at certain times of the year and have a circular shape; as the playa dries during the summer, conspicuous plant zonation develops along the shoreline. Prairie potholes are found in the northern parts of North America as the Prairie Pothole Region; these landscapes were once covered by glaciers, as a result shallow depressions were formed in great numbers. These depressions fill with water in the spring, they provide important breeding habitats for many species of waterfowl.
Some pools only occur seasonally. Many kinds of marsh occur along the fringes of large rivers; the different types are produced by factors such as water level, ice scour, waves. Large tracts of marshland have been embanked and ar
