Ecoregions Of Iowa
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An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural
communities A community is a Level of analysis, social unit (a group of living things) with commonality such as place (geography), place, Norm (social), norms, religion, values, Convention (norm), customs, or Identity (social science), identity. Communiti ...
and species. The biodiversity of flora, fauna and ecosystems that characterise an ecoregion tends to be distinct from that of other ecoregions. In theory, biodiversity or conservation ecoregions are relatively large areas of land or water where the probability of encountering different species and communities at any given point remains relatively constant, within an acceptable range of variation (largely undefined at this point). Three caveats are appropriate for all bio-geographic mapping approaches. Firstly, no single bio-geographic framework is optimal for all taxa. Ecoregions reflect the best compromise for as many taxa as possible. Secondly, ecoregion boundaries rarely form abrupt edges; rather, ecotones and mosaic habitats bound them. Thirdly, most ecoregions contain habitats that differ from their assigned biome. Biogeographic provinces may originate due to various barriers, including physical (plate tectonics, topographic highs), climatic (latitudinal variation, seasonal range) and ocean chemical related (salinity, oxygen levels).


History

The history of the term is somewhat vague, and it had been used in many contexts: forest classifications (Loucks, 1962), biome classifications (Bailey, 1976, 2014), biogeographic classifications ( WWF/ Global 200 scheme of Olson & Dinerstein, 1998), etc.Bailey, R. G. 2014. ''Ecoregions: The Ecosystem Geography of the. Oceans and Continents''. 2nd ed., Springer, 180 pp.

The concept of ecoregion applied by Bailey gives more importance to ecological criteria and climate, while the WWF concept gives more importance to biogeography, that is, the Species distribution, distribution of distinct species assemblages.


Definition and categorization

An ecoregion is a "recurring pattern of ecosystems associated with characteristic combinations of soil and
landform A landform is a natural or anthropogenic land feature on the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Landforms include hills, ...
that characterise that region". Omernik (2004) elaborates on this by defining ecoregions as: "areas within which there is spatial coincidence in characteristics of geographical phenomena associated with differences in the quality, health, and integrity of ecosystems". "Characteristics of geographical phenomena" may include geology, physiography, vegetation, climate, hydrology, terrestrial and aquatic fauna, and soils, and may or may not include the impacts of human activity (e.g. land use patterns, vegetation changes). There is significant, but not absolute, spatial correlation among these characteristics, making the delineation of ecoregions an imperfect science. Another complication is that environmental conditions across an ecoregion boundary may change very gradually, e.g. the prairie-forest transition in the midwestern United States, making it difficult to identify an exact dividing boundary. Such transition zones are called ecotones. Ecoregions can be categorized using an algorithmic approach or a holistic, "weight-of-evidence" approach where the importance of various factors may vary. An example of the algorithmic approach is Robert Bailey's work for the U.S. Forest Service, which uses a hierarchical classification that first divides land areas into very large regions based on climatic factors, and subdivides these regions, based first on dominant potential vegetation, and then by
geomorphology Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or n ...
and soil characteristics. The weight-of-evidence approach is exemplified by James Omernik's work for the United States Environmental Protection Agency, subsequently adopted (with modification) for
North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
by the
Commission for Environmental Cooperation The Commission for Environmental Cooperation (CEC; es, Comisión para la Cooperación Ambiental; french: Commission de coopération environnementale) was established by Canada, Mexico, and the United States to implement the North American Agree ...
. The intended purpose of ecoregion delineation may affect the method used. For example, the WWF ecoregions were developed to aid in biodiversity conservation planning, and place a greater emphasis than the Omernik or Bailey systems on floral and faunal differences between regions. The WWF classification defines an ecoregion as:
A large area of land or water that contains a geographically distinct assemblage of natural communities that: :(a) Share a large majority of their species and ecological dynamics; :(b) Share similar environmental conditions, and; :(c) Interact ecologically in ways that are critical for their long-term persistence.
According to WWF, the boundaries of an ecoregion approximate the original extent of the natural communities prior to any major recent disruptions or changes. WWF has identified 867 terrestrial ecoregions, and approximately 450 freshwater ecoregions across the Earth.


Importance

The use of the term ecoregion is an outgrowth of a surge of interest in ecosystems and their functioning. In particular, there is awareness of issues relating to spatial scale in the study and management of landscapes. It is widely recognized that interlinked ecosystems combine to form a whole that is "greater than the sum of its parts". There are many attempts to respond to ecosystems in an integrated way to achieve "multi-functional" landscapes, and various interest groups from
agricultural Agriculture or farming is the practice of cultivating Plant, plants and livestock. Agriculture was the key development in the rise of Sedentism, sedentary human civilization, whereby farming of Domestication, domesticated species created food ...
researchers to
conservationists The conservation movement, also known as nature conservation, is a political, environmental, and social movement that seeks to manage and protect natural resources, including animal, fungus, and plant species as well as their habitat for the f ...
are using the "ecoregion" as a unit of analysis. The " Global 200" is the list of ecoregions identified by WWF as priorities for conservation.


Terrestrial

Terrestrial ecoregions are land ecoregions, as distinct from freshwater and marine ecoregions. In this context, '' terrestrial'' is used to mean "of land" (soil and rock), rather than the more general sense "of Earth" (which includes land and oceans). WWF (World Wildlife Fund) ecologists currently divide the land surface of the Earth into eight
biogeographical realm A biogeographic realm or ecozone is the broadest biogeographic division of Earth's land surface, based on distributional patterns of terrestrial organisms. They are subdivided into bioregions, which are further subdivided into ecoregions. De ...
s containing 867 smaller terrestrial ecoregions (see list). The WWF effort is a synthesis of many previous efforts to define and classify ecoregions. The eight realms follow the major floral and faunal boundaries, identified by botanists and zoologists, that separate the world's major plant and animal communities. Realm boundaries generally follow continental boundaries, or major barriers to plant and animal distribution, like the Himalayas and the
Sahara , photo = Sahara real color.jpg , photo_caption = The Sahara taken by Apollo 17 astronauts, 1972 , map = , map_image = , location = , country = , country1 = , ...
. The boundaries of ecoregions are often not as decisive or well recognized, and are subject to greater disagreement. Ecoregions are classified by biome type, which are the major global plant communities determined by rainfall and climate. Forests, grasslands (including savanna and shrubland), and deserts (including
xeric shrublands Deserts and xeric shrublands are a biome defined by the World Wide Fund for Nature. Deserts and xeric (ancient Greek xērós, “dry") shrublands form the largest terrestrial biome, covering 19% of Earth's land surface area. Ecoregions in this h ...
) are distinguished by climate ( tropical and
subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Geographical z ...
vs. temperate and
boreal Boreal may refer to: Climatology and geography *Boreal (age), the first climatic phase of the Blytt-Sernander sequence of northern Europe, during the Holocene epoch *Boreal climate, a climate characterized by long winters and short, cool to mild ...
climates) and, for forests, by whether the trees are predominantly
conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ...
s ( gymnosperms), or whether they are predominantly broadleaf (
Angiosperm Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
s) and mixed (broadleaf and conifer). Biome types like
Mediterranean forests, woodlands, and scrub Mediterranean forests, woodlands, and scrub is a biome defined by the World Wide Fund for Nature. The biome is generally characterized by dry summers and rainy winters, although in some areas rainfall may be uniform. Summers are typically hot in ...
; tundra; and mangroves host very distinct ecological communities, and are recognized as distinct biome types as well.


Marine

Marine ecoregions are: "Areas of relatively homogeneous species composition, clearly distinct from adjacent systems….In ecological terms, these are strongly cohesive units, sufficiently large to encompass ecological or life history processes for most sedentary species." They have been defined by The Nature Conservancy (TNC) and World Wildlife Fund (WWF) to aid in conservation activities for marine ecosystems. Forty-three priority marine ecoregions were delineated as part of WWF's Global 200 efforts. The scheme used to designate and classify marine ecoregions is analogous to that used for terrestrial ecoregions. Major habitat types are identified: polar, temperate shelves and seas, temperate upwelling, tropical upwelling, tropical coral, pelagic (trades and westerlies), abyssal, and hadal (ocean trench). These correspond to the terrestrial
biomes A biome () is a biogeographical unit consisting of a biological community that has formed in response to the physical environment in which they are found and a shared regional climate. Biomes may span more than one continent. Biome is a broader ...
. The Global 200 classification of marine ecoregions is not developed to the same level of detail and comprehensiveness as that of the terrestrial ecoregions; only the priority conservation areas are listed. See Global 200 Marine ecoregions for a full list of marine ecoregions. In 2007, TNC and WWF refined and expanded this scheme to provide a system of comprehensive near shore (to 200 meters depth) Marine Ecoregions of the World (MEOW). The 232 individual marine ecoregions are grouped into 62
marine provinces The following is a list of marine ecoregions, as defined by the WWF and The Nature Conservancy The WWF/Nature Conservancy scheme groups the individual ecoregions into 12 marine realms, which represent the broad latitudinal divisions of polar, te ...
, which in turn group into 12
marine realms A marine ecoregion is an ecoregion, or ecological region, of the oceans and seas identified and defined based on biogeography, biogeographic characteristics. Introduction A more complete definition describes them as “Areas of relatively homogen ...
, which represent the broad latitudinal divisions of polar, temperate, and tropical seas, with subdivisions based on ocean basins (except for the southern hemisphere temperate oceans, which are based on continents). Major marine biogeographic realms, analogous to the eight terrestrial biogeographic realms, represent large regions of the ocean basins: Arctic, Temperate Northern Atlantic,
Temperate Northern Pacific The Temperate Northern Pacific is a biogeographic region of the Earth's seas, comprising the temperate waters of the northern Pacific Ocean. The Temperate Northern Pacific connects, via the Bering Sea, to the Arctic marine realm, which includes ...
,
Tropical Atlantic The Tropical Atlantic realm is one of twelve marine realms that cover the world's coastal seas and continental shelves. The Tropical Atlantic covers both sides of the Atlantic. In the western Atlantic, it extends from Bermuda, southern Florida, ...
, Western Indo-Pacific,
Central Indo-Pacific The Central Indo-Pacific is a biogeographic region of Earth's seas, comprising the tropical waters of the western Pacific Ocean, the eastern Indian Ocean, and the connecting seas. The Central Indo-Pacific is a part of the larger Indo-Pacific, w ...
,
Eastern Indo-Pacific The Eastern Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters around island groups in the central Pacific Ocean. It includes most of Polynesia, except for New Zealand and the Kermadec Islands. It also inclu ...
,
Tropical Eastern Pacific The Tropical Eastern Pacific is one of the twelve marine realms that cover the coastal waters and continental shelves of the world's oceans. The Tropical Eastern Pacific extends along the Pacific Coast of the Americas, from the southern tip of the ...
,
Temperate South America Temperate South America is a biogeography, biogeographic region of the Earth's seas, comprising the temperate and subtropical waters of South America, including both the Pacific Ocean, Pacific and Atlantic Ocean, Atlantic coasts of the continent a ...
,
Temperate Southern Africa Temperate Southern Africa is a biogeography, biogeographic region of the Earth's seas, comprising the temperate waters of southern Africa, where the Atlantic Ocean and Indian Ocean meet. It includes the coast of South Africa and Namibia, and reach ...
, Temperate Australasia, and Southern Ocean. A similar system of identifying areas of the oceans for conservation purposes is the system of large marine ecosystems (LMEs), developed by the US National Oceanic and Atmospheric Administration (NOAA).


Freshwater

A freshwater ecoregion is a large area encompassing one or more freshwater systems that contains a distinct assemblage of natural freshwater communities and species. The freshwater species, dynamics, and environmental conditions within a given ecoregion are more similar to each other than to those of surrounding ecoregions and together form a conservation unit. Freshwater systems include rivers,
stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a stream ...
s, lakes, and wetlands. Freshwater ecoregions are distinct from terrestrial ecoregions, which identify biotic communities of the land, and marine ecoregions, which are biotic communities of the oceans. A map of Freshwater Ecoregions of the World, released in 2008, has 426 ecoregions covering virtually the entire non-marine surface of the earth. World Wildlife Fund (WWF) identifies twelve major habitat types of freshwater ecoregions: Large lakes, large river deltas, polar freshwaters, montane freshwaters, temperate coastal rivers, temperate floodplain rivers and wetlands, temperate upland rivers, tropical and subtropical coastal rivers, tropical and subtropical floodplain rivers and wetlands, tropical and subtropical upland rivers, xeric freshwaters and endorheic basins, and oceanic islands. The freshwater major habitat types reflect groupings of ecoregions with similar biological, chemical, and physical characteristics and are roughly equivalent to biomes for terrestrial systems. The Global 200, a set of ecoregions identified by WWF whose conservation would achieve the goal of saving a broad diversity of the Earth's ecosystems, includes a number of areas highlighted for their freshwater biodiversity values. The Global 200 preceded Freshwater Ecoregions of the World and incorporated information from regional freshwater ecoregional assessments that had been completed at that time.


See also

*
Crisis ecoregion A crisis ecoregion is a terrestrial biome facing significant threat to its biodiversity and requiring well directed conservation efforts in order to curb the irreversible loss of plant and animal species and their surrounding habitats. Generally, an ...
*
Lists of ecoregions Wikipedia has articles relating to two separate ecoregion classification systems: *Ecoregions defined by the Commission for Environmental Cooperation and partner agencies in Canada, Mexico, and the United States: **List of ecoregions in North Ame ...


References


Bibliography

Sources related to the WWC scheme: * Main papers: ** Abell, R., M. Thieme, C. Revenga, M. Bryer, M. Kottelat, N. Bogutskaya, B. Coad, N. Mandrak, S. Contreras-Balderas, W. Bussing, M. L. J. Stiassny, P. Skelton, G. R. Allen, P. Unmack, A. Naseka, R. Ng, N. Sindorf, J. Robertson, E. Armijo, J. Higgins, T. J. Heibel, E. Wikramanayake, D. Olson, H. L. Lopez, R. E. d. Reis, J. G. Lundberg, M. H. Sabaj Perez, and P. Petry. (2008). Freshwater ecoregions of the world: A new map of biogeographic units for freshwater biodiversity conservation. ''BioScience'' 58:403-414

** Olson, D. M., Dinerstein, E., Wikramanayake, E. D., Burgess, N. D., Powell, G. V. N., Underwood, E. C., D'Amico, J. A., Itoua, I., Strand, H. E., Morrison, J. C., Loucks, C. J., Allnutt, T. F., Ricketts, T. H., Kura, Y., Lamoreux, J. F., Wettengel, W. W., Hedao, P., Kassem, K. R. (2001). Terrestrial ecoregions of the world: a new map of life on Earth. ''Bioscience'' 51(11):933-938

** Spalding, M. D. et al. (2007). Marine ecoregions of the world: a bioregionalization of coastal and shelf areas. ''BioScience'' 57: 573–583

* Africa: ** Burgess, N., J.D. Hales, E. Underwood, and E. Dinerstein (2004). ''Terrestrial Ecoregions of Africa and Madagascar: A Conservation Assessment.'' Island Press, Washington, D.C.

** Thieme, M.L., R. Abell, M.L.J. Stiassny, P. Skelton, B. Lehner, G.G. Teugels, E. Dinerstein, A.K. Toham, N. Burgess & D. Olson. 2005. ''Freshwater ecoregions of Africa and Madagascar: A conservation assessment.'' Washington DC: WWF

* Latin America ** Dinerstein, E., Olson, D. Graham, D.J. et al. (1995). ''A Conservation Assessment of the Terrestrial Ecoregions of Latin America and the Caribbean.'' World Bank, Washington DC.

** Olson, D. M., E. Dinerstein, G. Cintron, and P. Iolster. 1996. ''A conservation assessment of mangrove ecosystems of Latin America and the Caribbean''. Final report for The Ford Foundation. World Wildlife Fund, Washington, D.C. ** Olson, D. M., B. Chernoff, G. Burgess, I. Davidson, P. Canevari, E. Dinerstein, G. Castro, V. Morisset, R. Abell, and E. Toledo. 1997. ''Freshwater biodiversity of Latin America and the Caribbean: a conservation assessment''. Draft report. World Wildlife Fund-U.S., Wetlands International, Biodiversity Support Program, and United States Agency for International Development, Washington, D.C.

* North America ** Abell, R.A. et al. (2000). ''Freshwater Ecoregions of North America: A Conservation Assessment'' Washington, DC: Island Press

** Ricketts, T.H. et al. 1999. ''Terrestrial Ecoregions of North America: A Conservation Assessment''. Washington (DC): Island Press

* Russia and Indo-Pacific ** Krever, V., Dinerstein, E., Olson, D. and Williams, L. 1994. ''Conserving Russia's Biological Diversity: an analytical framework and initial investment portfolio''. WWF, Switzerland. ** Wikramanayake, E., E. Dinerstein, C. J. Loucks, D. M. Olson, J. Morrison, J. L. Lamoreux, M. McKnight, and P. Hedao. 2002. ''Terrestrial ecoregions of the Indo-Pacific: a conservation assessment''. Island Press, Washington, DC, USA

Others: * Brunckhorst, D. 2000. ''Bioregional planning: resource management beyond the new millennium.'' Harwood Academic Publishers: Sydney, Australia. * Busch, D.E. and J.C. Trexler. eds. 2003. Monitoring Ecosystems: Interdisciplinary approaches for evaluating ecoregional initiatives. Island Press. 447 pages.


External links


WWF WildFinder
(interactive on-line map of ecoregions with additional information about animal species) *
Original web page

Activist network cultivating Ecoregions/Bioregions
*
Original web page


{{Authority control Ecoregions, Biogeography