River ecosystemRiver ecosystems are flowing waters that drain the landscape, and include the biotic (living) interactions amongst plants, animals and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions of its many parts. River ecosystems are part of larger watershed networks or catchments, where smaller headwater streams drain into mid-size streams, which progressively drain into larger river networks. The major zones in river ecosystems are determined by the river bed's gradient or by the velocity of the current.
Habitat fragmentationHabitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processes that slowly alter the layout of the physical environment (suspected of being one of the major causes of speciation), and human activity such as land conversion, which can alter the environment much faster and causes the extinction of many species.
River engineeringRiver engineering is a discipline of civil engineering which studies human intervention in the course, characteristics, or flow of a river with the intention of producing some defined benefit. People have intervened in the natural course and behaviour of rivers since before recorded history—to manage the water resources, to protect against flooding, or to make passage along or across rivers easier. Since the Yuan Dynasty and Ancient Roman times, rivers have been used as a source of hydropower.
HabitatIn ecology, habitat refers to the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical manifestation of its ecological niche. Thus "habitat" is a species-specific term, fundamentally different from concepts such as environment or vegetation assemblages, for which the term "habitat-type" is more appropriate. The physical factors may include (for example): soil, moisture, range of temperature, and light intensity.
Forest restorationForest restoration is defined as “actions to re-instate ecological processes, which accelerate recovery of forest structure, ecological functioning and biodiversity levels towards those typical of climax forest” i.e. the end-stage of natural forest succession. Climax forests are relatively stable ecosystems that have developed the maximum biomass, structural complexity and species diversity that are possible within the limits imposed by climate and soil and without continued disturbance from humans (more explanation here).
Wildlife corridorA wildlife corridor, habitat corridor, or green corridor is an area of habitat connecting wildlife populations separated by human activities or structures (such as roads, development, or logging). This allows an exchange of individuals between populations, which may help prevent the negative effects of inbreeding and reduced genetic diversity (via genetic drift) that often occur within isolated populations. Corridors may also help facilitate the re-establishment of populations that have been reduced or eliminated due to random events (such as fires or disease).
Marine ecosystemMarine ecosystems are the largest of Earth's aquatic ecosystems and exist in waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 70% of the surface of the Earth and account for more than 97% of Earth's water supply and 90% of habitable space on Earth. Seawater has an average salinity of 35 parts per thousand of water. Actual salinity varies among different marine ecosystems.
Mississippi RiverThe Mississippi River is the primary river, and second-longest river, of the largest drainage basin in the United States. From its traditional source of Lake Itasca in northern Minnesota, it flows generally south for to the Mississippi River Delta in the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains all or parts of 32 U.S. states and two Canadian provinces between the Rocky and Appalachian mountains. The main stem is entirely within the United States; the total drainage basin is , of which only about one percent is in Canada.
Chicago RiverThe Chicago River is a system of rivers and canals with a combined length of that runs through the city of Chicago, including its center (the Chicago Loop). Though not especially long, the river is notable because it is one of the reasons for Chicago's geographic importance: the related Chicago Portage is a link between the Great Lakes and the Mississippi River Basin, and ultimately the Gulf of Mexico. The river is also noteworthy for its natural and human-engineered history.
Ecosystem collapseEcological collapse An ecosystem is considered collapsed when its unique biotic (characteristic biota) or abiotic features are lost from all previous occurrences. Ecosystem collapse causes ecological collapse within a system; essentially altering its stability, resilience, and diversity levels. It is, however, possible to reverse through careful restoration, and is thus not completely equivalent to species extinction.
