84-755: The Cascade–Siskiyou National Monument is a United States national monument that protects 114,000 acres (46,134 ha) of forest and grasslands at the junction of the Cascade Range and the Siskiyou Mountains in Southwestern Oregon and Northwestern California , United States. The monument is managed by the Bureau of Land Management as part of the National Landscape Conservation System . It
168-409: A cell wall . Newly dead animals may be covered by an exoskeleton . Fragmentation processes, which break through these protective layers, accelerate the rate of microbial decomposition. Animals fragment detritus as they hunt for food, as does passage through the gut. Freeze-thaw cycles and cycles of wetting and drying also fragment dead material. The chemical alteration of the dead organic matter
252-564: A conservation easement on a 1,312-acre (531 ha) private property near Siskiyou Summit . In May 2015, 70 scientists endorsed the April 2011 Cascade–Siskiyou Scientific Report and the need for monument expansion bringing the total number of scientists speaking out on expansion to 85. Additionally, science-based expansion of the Cascade–Siskiyou National Monument is formally endorsed in writing by: The monument expansion
336-495: A food chain . Real systems are much more complex than this—organisms will generally feed on more than one form of food, and may feed at more than one trophic level. Carnivores may capture some prey that is part of a plant-based trophic system and others that are part of a detritus-based trophic system (a bird that feeds both on herbivorous grasshoppers and earthworms, which consume detritus). Real systems, with all these complexities, form food webs rather than food chains which present
420-619: A habitat . Ecosystem ecology is the "study of the interactions between organisms and their environment as an integrated system". The size of ecosystems can range up to ten orders of magnitude , from the surface layers of rocks to the surface of the planet. The Hubbard Brook Ecosystem Study started in 1963 to study the White Mountains in New Hampshire . It was the first successful attempt to study an entire watershed as an ecosystem. The study used stream chemistry as
504-609: A central role over a wide range, for example, in the slow development of soil from bare rock and the faster recovery of a community from disturbance . Disturbance also plays an important role in ecological processes. F. Stuart Chapin and coauthors define disturbance as "a relatively discrete event in time that removes plant biomass". This can range from herbivore outbreaks, treefalls, fires, hurricanes, floods, glacial advances , to volcanic eruptions . Such disturbances can cause large changes in plant, animal and microbe populations, as well as soil organic matter content. Disturbance
588-507: A critical role in global nutrient cycling and ecosystem function. Phosphorus enters ecosystems through weathering . As ecosystems age this supply diminishes, making phosphorus-limitation more common in older landscapes (especially in the tropics). Calcium and sulfur are also produced by weathering, but acid deposition is an important source of sulfur in many ecosystems. Although magnesium and manganese are produced by weathering, exchanges between soil organic matter and living cells account for
672-478: A donation of lands acquired by John D. Rockefeller Jr. , for addition to Grand Teton National Park after Congress had declined to authorize this park expansion. Roosevelt's proclamation unleashed a storm of criticism about use of the Antiquities Act to circumvent Congress. A bill abolishing Jackson Hole National Monument passed Congress but was vetoed by Roosevelt, and Congressional and court challenges to
756-517: A faster recovery. More severe and more frequent disturbance result in longer recovery times. From one year to another, ecosystems experience variation in their biotic and abiotic environments. A drought , a colder than usual winter, and a pest outbreak all are short-term variability in environmental conditions. Animal populations vary from year to year, building up during resource-rich periods and crashing as they overshoot their food supply. Longer-term changes also shape ecosystem processes. For example,
840-837: A fifth in the Atlantic Ocean, the Northeast Canyons and Seamounts Marine National Monument . On June 24, 2016, Obama designated the Stonewall Inn and surrounding areas in Greenwich Village , New York as the Stonewall National Monument , the first national monument commemorating the movement for LGBT rights in the United States . Obama's establishments included several others recognizing civil rights history, including
924-454: A form that can be readily used by plants and microbes. Ecosystems provide a variety of goods and services upon which people depend, and may be part of. Ecosystem goods include the "tangible, material products" of ecosystem processes such as water, food, fuel, construction material, and medicinal plants . Ecosystem services , on the other hand, are generally "improvements in the condition or location of things of value". These include things like
SECTION 10
#17327917731561008-427: A function-based typology has been proposed to leverage the strengths of these different approaches into a unified system. Human activities are important in almost all ecosystems. Although humans exist and operate within ecosystems, their cumulative effects are large enough to influence external factors like climate. Ecosystems provide a variety of goods and services upon which people depend. Ecosystem goods include
1092-698: A general level, for example, tropical forests , temperate grasslands , and arctic tundra . There can be any degree of subcategories among ecosystem types that comprise a biome, e.g., needle-leafed boreal forests or wet tropical forests. Although ecosystems are most commonly categorized by their structure and geography, there are also other ways to categorize and classify ecosystems such as by their level of human impact (see anthropogenic biome ), or by their integration with social processes or technological processes or their novelty (e.g. novel ecosystem ). Each of these taxonomies of ecosystems tends to emphasize different structural or functional properties. None of these
1176-477: A major Alaska lands bill. Congress passed a revised version of the bill in 1980 incorporating most of these national monuments into national parks and preserves , but the act also curtailed further use of the proclamation authority in Alaska. Carter's 1978 proclamations included Misty Fjords and Admiralty Island National Monuments in the U.S. Forest Service and Becharof and Yukon Flats National Monuments in
1260-672: A means of monitoring ecosystem properties, and developed a detailed biogeochemical model of the ecosystem. Long-term research at the site led to the discovery of acid rain in North America in 1972. Researchers documented the depletion of soil cations (especially calcium) over the next several decades. Ecosystems can be studied through a variety of approaches—theoretical studies, studies monitoring specific ecosystems over long periods of time, those that look at differences between ecosystems to elucidate how they work and direct manipulative experimentation. Studies can be carried out at
1344-528: A more important role in moving nutrients around. This can be especially important as the soil thaws in the spring, creating a pulse of nutrients that become available. Decomposition rates are low under very wet or very dry conditions. Decomposition rates are highest in wet, moist conditions with adequate levels of oxygen. Wet soils tend to become deficient in oxygen (this is especially true in wetlands ), which slows microbial growth. In dry soils, decomposition slows as well, but bacteria continue to grow (albeit at
1428-406: A number of common, non random properties in the topology of their network. The carbon and nutrients in dead organic matter are broken down by a group of processes known as decomposition. This releases nutrients that can then be re-used for plant and microbial production and returns carbon dioxide to the atmosphere (or water) where it can be used for photosynthesis. In the absence of decomposition,
1512-525: A precedent for the use of the Antiquities Act to preserve large areas. Federal courts have since rejected every challenge to the president's use of Antiquities Act preservation authority, ruling that the law gives the president exclusive discretion over the determination of the size and nature of the objects protected. In 1918, President Woodrow Wilson proclaimed Katmai National Monument in Alaska , comprising more than 1,000,000 acres (4,000 km ). Katmai
1596-421: A process known as denitrification . Mycorrhizal fungi which are symbiotic with plant roots, use carbohydrates supplied by the plants and in return transfer phosphorus and nitrogen compounds back to the plant roots. This is an important pathway of organic nitrogen transfer from dead organic matter to plants. This mechanism may contribute to more than 70 Tg of annually assimilated plant nitrogen, thereby playing
1680-696: A significant portion of ecosystem fluxes. Potassium is primarily cycled between living cells and soil organic matter. Biodiversity plays an important role in ecosystem functioning. Ecosystem processes are driven by the species in an ecosystem, the nature of the individual species, and the relative abundance of organisms among these species. Ecosystem processes are the net effect of the actions of individual organisms as they interact with their environment. Ecological theory suggests that in order to coexist, species must have some level of limiting similarity —they must be different from one another in some fundamental way, otherwise, one species would competitively exclude
1764-408: A slower rate) even after soils become too dry to support plant growth. Ecosystems are dynamic entities. They are subject to periodic disturbances and are always in the process of recovering from past disturbances. When a perturbation occurs, an ecosystem responds by moving away from its initial state. The tendency of an ecosystem to remain close to its equilibrium state, despite that disturbance,
SECTION 20
#17327917731561848-464: A small effect on ecosystem function. Ecologically distinct species, on the other hand, have a much larger effect. Similarly, dominant species have a large effect on ecosystem function, while rare species tend to have a small effect. Keystone species tend to have an effect on ecosystem function that is disproportionate to their abundance in an ecosystem. An ecosystem engineer is any organism that creates, significantly modifies, maintains or destroys
1932-526: A system to absorb disturbance and reorganize while undergoing change so as to retain essentially the same function, structure, identity, and feedbacks is termed its ecological resilience . Ecosystems can be studied through a variety of approaches—theoretical studies, studies monitoring specific ecosystems over long periods of time, those that look at differences between ecosystems to elucidate how they work and direct manipulative experimentation. Biomes are general classes or categories of ecosystems. However, there
2016-522: A variety of scales, ranging from whole-ecosystem studies to studying microcosms or mesocosms (simplified representations of ecosystems). American ecologist Stephen R. Carpenter has argued that microcosm experiments can be "irrelevant and diversionary" if they are not carried out in conjunction with field studies done at the ecosystem scale. In such cases, microcosm experiments may fail to accurately predict ecosystem-level dynamics. Biomes are general classes or categories of ecosystems. However, there
2100-458: Is an international synthesis by over 1000 of the world's leading biological scientists that analyzes the state of the Earth's ecosystems and provides summaries and guidelines for decision-makers. The report identified four major categories of ecosystem services: provisioning, regulating, cultural and supporting services. It concludes that human activity is having a significant and escalating impact on
2184-442: Is consumed by animals while still alive and enters the plant-based trophic system. After plants and animals die, the organic matter contained in them enters the detritus-based trophic system. Ecosystem respiration is the sum of respiration by all living organisms (plants, animals, and decomposers) in the ecosystem. Net ecosystem production is the difference between gross primary production (GPP) and ecosystem respiration. In
2268-423: Is controlled by internal factors. Therefore, internal factors not only control ecosystem processes but are also controlled by them. Ecosystems are dynamic entities—they are subject to periodic disturbances and are always in the process of recovering from some past disturbance. The tendency of an ecosystem to remain close to its equilibrium state, despite that disturbance, is termed its resistance . The capacity of
2352-569: Is followed by succession, a "directional change in ecosystem structure and functioning resulting from biotically driven changes in resource supply." The frequency and severity of disturbance determine the way it affects ecosystem function. A major disturbance like a volcanic eruption or glacial advance and retreat leave behind soils that lack plants, animals or organic matter. Ecosystems that experience such disturbances undergo primary succession . A less severe disturbance like forest fires, hurricanes or cultivation result in secondary succession and
2436-554: Is governed by three sets of factors—the physical environment (temperature, moisture, and soil properties), the quantity and quality of the dead material available to decomposers, and the nature of the microbial community itself. Temperature controls the rate of microbial respiration; the higher the temperature, the faster the microbial decomposition occurs. Temperature also affects soil moisture, which affects decomposition. Freeze-thaw cycles also affect decomposition—freezing temperatures kill soil microorganisms, which allows leaching to play
2520-405: Is no clear distinction between biomes and ecosystems. Biomes are always defined at a very general level. Ecosystems can be described at levels that range from very general (in which case the names are sometimes the same as those of biomes) to very specific, such as "wet coastal needle-leafed forests". Biomes vary due to global variations in climate . Biomes are often defined by their structure: at
2604-516: Is no clear distinction between biomes and ecosystems. Ecosystem classifications are specific kinds of ecological classifications that consider all four elements of the definition of ecosystems : a biotic component, an abiotic complex, the interactions between and within them, and the physical space they occupy. Biotic factors of the ecosystem are living things; such as plants, animals, and bacteria, while abiotic are non-living components; such as water, soil and atmosphere. Plants allow energy to enter
Cascade–Siskiyou National Monument - Misplaced Pages Continue
2688-1057: Is opposed by the Boards of Commissioners of Jackson County and Klamath County (both in Oregon); and the Siskiyou County Board of Supervisors (in California). A group of local people calling themselves the "No Monument Tribe" opposes the monument in its entirety, both the initial establishment and the expansion. On January 12, 2017, President Barack Obama expanded the monument by 48,000 acres (19,000 ha). The expansion contains 5,000 acres (2,000 ha) in Northern California, in addition to 43,000 acres (17,000 ha) in Oregon. Federal judges in Washington, DC and Oregon issued conflicting decisions in 2019 over
2772-531: Is primarily achieved through bacterial and fungal action. Fungal hyphae produce enzymes that can break through the tough outer structures surrounding dead plant material. They also produce enzymes that break down lignin , which allows them access to both cell contents and the nitrogen in the lignin. Fungi can transfer carbon and nitrogen through their hyphal networks and thus, unlike bacteria, are not dependent solely on locally available resources. Decomposition rates vary among ecosystems. The rate of decomposition
2856-485: Is termed its resistance . The capacity of a system to absorb disturbance and reorganize while undergoing change so as to retain essentially the same function, structure, identity, and feedbacks is termed its ecological resilience . Resilience thinking also includes humanity as an integral part of the biosphere where we are dependent on ecosystem services for our survival and must build and maintain their natural capacities to withstand shocks and disturbances. Time plays
2940-422: Is the "best" classification. Ecosystem classifications are specific kinds of ecological classifications that consider all four elements of the definition of ecosystems : a biotic component, an abiotic complex, the interactions between and within them, and the physical space they occupy. Different approaches to ecological classifications have been developed in terrestrial, freshwater and marine disciplines, and
3024-488: The Cascade Range . Two hundred species of birds are known to exist in the monument including some threatened and endangered species. Amphibians found in the National Monument include the rough-skinned newt . Cascade–Siskiyou National Monument is noted for its significant botanical diversity. The range of elevations and diversity of habitat types provides for a spectacular flora that includes many endemics to
3108-580: The César E. Chávez , Belmont–Paul Women's Equality , Freedom Riders , and Birmingham Civil Rights National Monuments . In December 2017, President Donald Trump substantially reduced the sizes of Bears Ears and Grand Staircase–Escalante National Monuments , removing protections on about 2.8 million acres of land where mining could resume. Three lawsuits challenged the legality of this action in federal court, and in October 2021, President Joe Biden reversed
3192-662: The Fish and Wildlife Service , the first to be created outside of the National Park Service. The latter two became national wildlife refuges in 1980. The proclamation authority was not used again anywhere until 1996, when President Bill Clinton proclaimed the Grand Staircase–Escalante National Monument in Utah , after many years of unsuccessful advocacy by conservationists to protect parts of
3276-655: The Grand Canyon as a national monument. In response to Roosevelt's declaration of the Grand Canyon monument, a putative mining claimant sued in federal court, claiming that Roosevelt had overstepped the Antiquities Act authority by protecting an entire canyon. In 1920, the United States Supreme Court ruled unanimously that the Grand Canyon was indeed "an object of historic or scientific interest" and could be protected by proclamation, setting
3360-670: The National Park Service , United States Forest Service , United States Fish and Wildlife Service , the Bureau of Land Management , and the National Oceanic and Atmospheric Administration (in the case of marine national monuments). Historically, some national monuments were managed by the War Department . President Theodore Roosevelt used the Antiquities Act to declare Devils Tower in Wyoming as
3444-618: The president of the United States or an act of Congress. National monuments protect a wide variety of natural and historic resources, including sites of geologic, marine, archaeological, and cultural importance. The Antiquities Act of 1906 gives presidents the power to proclaim national monuments by executive action. In contrast, national parks in the U.S. must be created by Congressional legislation. Some national monuments were first created by presidential action and later designated as national parks by congressional approval. The 134 national monuments are managed by several federal agencies:
Cascade–Siskiyou National Monument - Misplaced Pages Continue
3528-555: The resource inputs are generally controlled by external processes like climate and parent material, the availability of these resources within the ecosystem is controlled by internal factors like decomposition, root competition or shading. Other factors like disturbance, succession or the types of species present are also internal factors. Primary production is the production of organic matter from inorganic carbon sources. This mainly occurs through photosynthesis . The energy incorporated through this process supports life on earth, while
3612-435: The "tangible, material products" of ecosystem processes such as water, food, fuel, construction material, and medicinal plants . They also include less tangible items like tourism and recreation, and genes from wild plants and animals that can be used to improve domestic species. Ecosystem services , on the other hand, are generally "improvements in the condition or location of things of value". These include things like
3696-512: The 1880s, their lands were taken by white settlers, whose mining cabins still dot the region. Natural features in the monument include Pilot Rock , a volcanic neck or interior of an extinct volcano, similarly formed as Devils Tower in Wyoming , and the Soda Mountain Wilderness . The Pacific Crest Trail runs through the monument area. There is a fire lookout tower on the top of Soda Mountain built in 1962 to replace
3780-560: The American West. The reference in the act to "objects of ... scientific interest" enabled President Theodore Roosevelt to make a natural geological feature, Devils Tower in Wyoming , the first national monument three months later. Among the next three monuments he proclaimed in 1906 was Petrified Forest in Arizona , another natural feature. In 1908, Roosevelt used the act to proclaim more than 800,000 acres (3,200 km ) of
3864-996: The Pacific Ocean, the largest in the system: the Papahānaumokuākea Marine National Monument , the Pacific Remote Islands Marine National Monument , the Marianas Marine National Monument , and the Rose Atoll Marine National Monument . They are managed by the Fish and Wildlife Service, with the National Oceanic and Atmospheric Administration overseeing the fisheries. President Barack Obama significantly expanded two of them and added
3948-481: The absence of disturbance, net ecosystem production is equivalent to the net carbon accumulation in the ecosystem. Energy can also be released from an ecosystem through disturbances such as wildfire or transferred to other ecosystems (e.g., from a forest to a stream to a lake) by erosion . In aquatic systems , the proportion of plant biomass that gets consumed by herbivores is much higher than in terrestrial systems. In trophic systems, photosynthetic organisms are
4032-402: The amount of energy available to the ecosystem. Parent material determines the nature of the soil in an ecosystem, and influences the supply of mineral nutrients. Topography also controls ecosystem processes by affecting things like microclimate , soil development and the movement of water through a system. For example, ecosystems can be quite different if situated in a small depression on
4116-504: The amount of light available, the amount of leaf area a plant has to capture light (shading by other plants is a major limitation of photosynthesis), the rate at which carbon dioxide can be supplied to the chloroplasts to support photosynthesis, the availability of water, and the availability of suitable temperatures for carrying out photosynthesis. Energy and carbon enter ecosystems through photosynthesis, are incorporated into living tissue, transferred to other organisms that feed on
4200-609: The area. This was the first national monument managed by the Bureau of Land Management . This action was unpopular in Utah, and bills were introduced to further restrict the president's authority, none of which have been enacted. Most of the 16 national monuments created by President Clinton are managed not by the National Park Service, but by the Bureau of Land Management as part of the National Landscape Conservation System . President George W. Bush created four marine national monuments in
4284-408: The carbon makes up much of the organic matter in living and dead biomass, soil carbon and fossil fuels . It also drives the carbon cycle , which influences global climate via the greenhouse effect . Through the process of photosynthesis, plants capture energy from light and use it to combine carbon dioxide and water to produce carbohydrates and oxygen . The photosynthesis carried out by all
SECTION 50
#17327917731564368-668: The changes. The restoration of the monuments has been challenged in court in an attempt to attack the Antiquities Act. President Biden's proclamations establishing and expanding monuments often incorporated consultation with Native American tribes for management and planning. Ecosystem An ecosystem (or ecological system ) is a system that environments and their organisms form through their interaction. The biotic and abiotic components are linked together through nutrient cycles and energy flows. Ecosystems are controlled by external and internal factors . External factors such as climate , parent material which forms
4452-432: The combustion of fossil fuels, ammonia gas which evaporates from agricultural fields which have had fertilizers applied to them, and dust. Anthropogenic nitrogen inputs account for about 80% of all nitrogen fluxes in ecosystems. When plant tissues are shed or are eaten, the nitrogen in those tissues becomes available to animals and microbes. Microbial decomposition releases nitrogen compounds from dead organic matter in
4536-418: The concept to draw attention to the importance of transfers of materials between organisms and their environment. He later refined the term, describing it as "The whole system, ... including not only the organism-complex, but also the whole complex of physical factors forming what we call the environment". Tansley regarded ecosystems not simply as natural units, but as "mental isolates". Tansley later defined
4620-403: The dead organic matter would accumulate in an ecosystem, and nutrients and atmospheric carbon dioxide would be depleted. Decomposition processes can be separated into three categories— leaching , fragmentation and chemical alteration of dead material. As water moves through dead organic matter, it dissolves and carries with it the water-soluble components. These are then taken up by organisms in
4704-655: The ecosystem or to gradual disruption of biotic processes and degradation of abiotic conditions of the ecosystem. Once the original ecosystem has lost its defining features, it is considered "collapsed ". Ecosystem restoration can contribute to achieving the Sustainable Development Goals . An ecosystem (or ecological system) consists of all the organisms and the abiotic pools (or physical environment) with which they interact. The biotic and abiotic components are linked together through nutrient cycles and energy flows. "Ecosystem processes" are
4788-453: The first U.S. national monument. The Antiquities Act authorized permits for legitimate archaeological investigations and penalties for taking or destroying antiquities without permission. Additionally, it authorized the president to proclaim "historic landmarks, historic and prehistoric structures, and other objects of historic or scientific interest" on federal lands as national monuments, "the limits of which in all cases shall be confined to
4872-421: The flow of energy through a lake was the primary driver of the ecosystem. Hutchinson's students, brothers Howard T. Odum and Eugene P. Odum , further developed a "systems approach" to the study of ecosystems. This allowed them to study the flow of energy and material through ecological systems. Ecosystems are controlled by both external and internal factors. External factors, also called state factors, control
4956-458: The forests of eastern North America still show legacies of cultivation which ceased in 1850 when large areas were reverted to forests. Another example is the methane production in eastern Siberian lakes that is controlled by organic matter which accumulated during the Pleistocene . Ecosystems continually exchange energy and carbon with the wider environment . Mineral nutrients, on
5040-479: The immediate Siskiyou crest area, such as Green's mariposa lily ( Calochortus greenei ). The federally endangered Gentner's fritillary ( Fritillaria gentneri ) is known to occur in the monument. National monument (United States) In the United States , a national monument is a protected area that can be created from any land owned or controlled by the federal government by proclamation of
5124-691: The landscape, versus one present on an adjacent steep hillside. Other external factors that play an important role in ecosystem functioning include time and potential biota , the organisms that are present in a region and could potentially occupy a particular site. Ecosystems in similar environments that are located in different parts of the world can end up doing things very differently simply because they have different pools of species present. The introduction of non-native species can cause substantial shifts in ecosystem function. Unlike external factors, internal factors in ecosystems not only control ecosystem processes but are also controlled by them. While
SECTION 60
#17327917731565208-407: The legality of the expansion into O&C Lands . In 2023 both the 9th and DC Circuit Courts of Appeals upheld the expanded national monument designation. The Supreme Court declined to take up the two decisions in 2024. The Cascade–Siskiyou National Monument is the first U.S. national monument set aside solely for the preservation of biodiversity. It has one of the most diverse ecosystems found in
5292-423: The living and dead plant matter, and eventually released through respiration. The carbon and energy incorporated into plant tissues (net primary production) is either consumed by animals while the plant is alive, or it remains uneaten when the plant tissue dies and becomes detritus . In terrestrial ecosystems , the vast majority of the net primary production ends up being broken down by decomposers . The remainder
5376-471: The maintenance of hydrological cycles , cleaning air and water, the maintenance of oxygen in the atmosphere, crop pollination and even things like beauty, inspiration and opportunities for research. Many ecosystems become degraded through human impacts, such as soil loss , air and water pollution , habitat fragmentation , water diversion , fire suppression , and introduced species and invasive species . These threats can lead to abrupt transformation of
5460-408: The maintenance of hydrological cycles, cleaning air and water, the maintenance of oxygen in the atmosphere, crop pollination and even things like beauty, inspiration and opportunities for research. While material from the ecosystem had traditionally been recognized as being the basis for things of economic value, ecosystem services tend to be taken for granted. The Millennium Ecosystem Assessment
5544-419: The original 1933 structure. Although the top of the mountain is also the site of dozens of television and radio broadcast and relay dishes, the view from the fire lookout of the surrounding mountains is unobstructed. From the lookout, one can see Mount Shasta , Mount Ashland , Mount McLoughlin , as well as on clear days, the rim of Crater Lake . The Cascade–Siskiyou National Monument land use plan has been
5628-537: The other hand, are mostly cycled back and forth between plants, animals, microbes and the soil. Most nitrogen enters ecosystems through biological nitrogen fixation , is deposited through precipitation, dust, gases or is applied as fertilizer . Most terrestrial ecosystems are nitrogen-limited in the short term making nitrogen cycling an important control on ecosystem production. Over the long term, phosphorus availability can also be critical. Macronutrients which are required by all plants in large quantities include
5712-509: The other. Despite this, the cumulative effect of additional species in an ecosystem is not linear: additional species may enhance nitrogen retention, for example. However, beyond some level of species richness, additional species may have little additive effect unless they differ substantially from species already present. This is the case for example for exotic species . The addition (or loss) of species that are ecologically similar to those already present in an ecosystem tends to only have
5796-403: The overall structure of an ecosystem and the way things work within it, but are not themselves influenced by the ecosystem. On broad geographic scales, climate is the factor that "most strongly determines ecosystem processes and structure". Climate determines the biome in which the ecosystem is embedded. Rainfall patterns and seasonal temperatures influence photosynthesis and thereby determine
5880-405: The plants in an ecosystem is called the gross primary production (GPP). About half of the gross GPP is respired by plants in order to provide the energy that supports their growth and maintenance. The remainder, that portion of GPP that is not used up by respiration, is known as the net primary production (NPP). Total photosynthesis is limited by a range of environmental factors. These include
5964-585: The primary nutrients (which are most limiting as they are used in largest amounts): Nitrogen, phosphorus, potassium. Secondary major nutrients (less often limiting) include: Calcium, magnesium, sulfur. Micronutrients required by all plants in small quantities include boron, chloride, copper, iron, manganese, molybdenum, zinc. Finally, there are also beneficial nutrients which may be required by certain plants or by plants under specific environmental conditions: aluminum, cobalt, iodine, nickel, selenium, silicon, sodium, vanadium. Until modern times, nitrogen fixation
6048-413: The primary producers. The organisms that consume their tissues are called primary consumers or secondary producers — herbivores . Organisms which feed on microbes ( bacteria and fungi ) are termed microbivores . Animals that feed on primary consumers— carnivores —are secondary consumers. Each of these constitutes a trophic level. The sequence of consumption—from plant to herbivore, to carnivore—forms
6132-512: The proclamation authority were mounted. In 1950, Congress finally incorporated most of the monument into Grand Teton National Park, but the act doing so barred further use of the proclamation authority in Wyoming except for areas of 5,000 acres or less. The most substantial use of the proclamation authority came in 1978, when President Jimmy Carter proclaimed 17 new national monuments in Alaska after Congress had adjourned without passing
6216-707: The smallest area compatible with the proper care and management of the objects to be protected." Presidents have used the Antiquities Act's proclamation authority not only to create new national monuments but to enlarge existing ones. For example, Franklin D. Roosevelt significantly enlarged Dinosaur National Monument in 1938. Lyndon B. Johnson added Ellis Island to Statue of Liberty National Monument in 1965, and Jimmy Carter made major additions to Glacier Bay and Katmai National Monuments in 1978. The Antiquities Act of 1906 resulted from concerns about protecting mostly prehistoric Native American ruins and artifacts (collectively termed "antiquities") on federal lands in
6300-409: The soil and topography , control the overall structure of an ecosystem but are not themselves influenced by the ecosystem. Internal factors are controlled, for example, by decomposition , root competition, shading, disturbance, succession, and the types of species present. While the resource inputs are generally controlled by external processes, the availability of these resources within the ecosystem
6384-611: The soil, react with mineral soil, or are transported beyond the confines of the ecosystem (and are considered lost to it). Newly shed leaves and newly dead animals have high concentrations of water-soluble components and include sugars , amino acids and mineral nutrients. Leaching is more important in wet environments and less important in dry ones. Fragmentation processes break organic material into smaller pieces, exposing new surfaces for colonization by microbes. Freshly shed leaf litter may be inaccessible due to an outer layer of cuticle or bark , and cell contents are protected by
6468-511: The soil, where plants, fungi, and bacteria compete for it. Some soil bacteria use organic nitrogen-containing compounds as a source of carbon, and release ammonium ions into the soil. This process is known as nitrogen mineralization . Others convert ammonium to nitrite and nitrate ions, a process known as nitrification . Nitric oxide and nitrous oxide are also produced during nitrification. Under nitrogen-rich and oxygen-poor conditions, nitrates and nitrites are converted to nitrogen gas ,
6552-459: The source of local and national controversy over multi-use planning for wilderness and roadless areas . The plan currently strives for a balance between managing rare natural habitat, recreational activities, and agricultural activities including cattle grazing and timber. Numerous private land inholdings remain within the boundaries of the Monument. The Southern Oregon Land Conservancy holds
6636-483: The spatial extent of ecosystems using the term " ecotope ". G. Evelyn Hutchinson , a limnologist who was a contemporary of Tansley's, combined Charles Elton 's ideas about trophic ecology with those of Russian geochemist Vladimir Vernadsky . As a result, he suggested that mineral nutrient availability in a lake limited algal production . This would, in turn, limit the abundance of animals that feed on algae. Raymond Lindeman took these ideas further to suggest that
6720-454: The system through photosynthesis , building up plant tissue. Animals play an important role in the movement of matter and energy through the system, by feeding on plants and on one another. They also influence the quantity of plant and microbial biomass present. By breaking down dead organic matter , decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to
6804-421: The transfers of energy and materials from one pool to another. Ecosystem processes are known to "take place at a wide range of scales". Therefore, the correct scale of study depends on the question asked. The term "ecosystem" was first used in 1935 in a publication by British ecologist Arthur Tansley . The term was coined by Arthur Roy Clapham , who came up with the word at Tansley's request. Tansley devised
6888-457: Was established in a presidential proclamation by President Bill Clinton on June 9, 2000 and expanded by President Barack Obama on January 12, 2017. Native Americans are known from archaeological excavations to have inhabited the region for thousands of years. Nearly 100 dwelling and root-gathering sites belonging to the Modoc , Klamath , and Shasta tribes have been uncovered to date. By
6972-550: Was later enlarged to nearly 2,800,000 acres (11,000 km ) by subsequent Antiquities Act proclamations and for many years was the largest national park system unit. Petrified Forest , Grand Canyon , and Great Sand Dunes , among several other national parks , were also originally proclaimed as national monuments and later designated national parks by Congress. Substantial opposition did not materialize until 1943, when President Franklin D. Roosevelt proclaimed Jackson Hole National Monument in Wyoming . He did this to accept
7056-679: Was the major source of nitrogen for ecosystems. Nitrogen-fixing bacteria either live symbiotically with plants or live freely in the soil. The energetic cost is high for plants that support nitrogen-fixing symbionts—as much as 25% of gross primary production when measured in controlled conditions. Many members of the legume plant family support nitrogen-fixing symbionts. Some cyanobacteria are also capable of nitrogen fixation. These are phototrophs , which carry out photosynthesis. Like other nitrogen-fixing bacteria, they can either be free-living or have symbiotic relationships with plants. Other sources of nitrogen include acid deposition produced through
#155844