Everything about Ecoregions totally explained
An
ecoregion (
ecological region), sometimes called a
bioregion, is a
ecologically and geographically defined area smaller than a "realm" or "
ecozone". Ecoregions cover relatively large area of land or water, and contain characteristic, geographically distinct assemblage of natural
communities and
species. The
biodiversity of
flora,
fauna and
ecosystems that characterise an ecoregion tend to be distinct from that of other ecoregions.
Definitions
The definition of the
Worldwide Fund for Nature (WWF) is widely used:
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 825 terrestrial ecoregions, and approximately 450 freshwater ecoregions across the Earth. Another way of defining an ecoregion is as a "recurring pattern of ecosystems associated with characteristic combinations of
soil and
landform that characterise that region" (Brunckhorst, 2000).
Others have defined ecoregions as areas of
ecological potential based on combinations of biophysical parameters such as
climate and
topography.
Importance
The use of the term ecoregion is an outgrowth of a surge of interest in ecosystems and their functioning. In particular, there's 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's "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 researchers to
conservationists are using the "ecoregion" as a unit of analysis.
The "Global 200" is the list of ecoregions identified by WWF as priorities for
conservation.
Ecologically-based movements like
bioregionalism maintain that ecoregions, rather than arbitrarily-defined political boundaries, provide a better foundation for the formation and governance of human communities, and have proposed ecoregions and
watersheds as the basis for
bioregional democracy initiatives.
Terrestrial ecoregions
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
ecologists currently divide the land surface of the
Earth into 8 major
ecozones containing 867 smaller terrestrial ecoregions (see
list). The WWF effort is a synthesis of many previous efforts to define and classify ecoregions. Many consider this classification to be quite decisive, and some propose these as stable borders for
bioregional democracy initiatives.
The eight terrestrial ecozones follow the major floral and faunal boundaries, identified by botanists and zoologists, that separate the world's major plant and animal communities. Ecozone boundaries generally follow
continental boundaries, or major barriers to plant and animal distribution, like the
Himalayas and the
Sahara. 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) are distinguished by climate (
tropical and
subtropical vs.
temperate and
boreal climates) and, for forests, by whether the trees are predominantly
conifers (
gymnosperms), or whether they're predominantly broadleaf (
Angiosperms) and mixed (broadleaf and conifer). Biome types like
Mediterranean forests, woodlands, and shrub,
tundra, and
mangroves host very distinct ecological communities, and are recognized as distinct biome types as well.
Marine ecoregions
Marine ecoregions are regions of the world's oceans, as defined by WWF to aid in
conservation activities for
marine ecosystems.
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. Major biogeographic realms, analogous to the seven terrestrial
ecozones, represent large regions of the ocean basins: North Temperate Atlantic, Eastern Tropical Atlantic, Western Tropical Atlantic, South Temperate Atlantic, North Temperate Indo-Pacific, Central Indo-Pacific, Eastern Indo-Pacific, Western Indo-Pacific, South Temperate Indo-Pacific, Southern Ocean, Antarctic, Arctic, and Mediterranean.
The classification of Marine ecoregions isn't developed to the same level of detail and comprehensiveness as that of the terrestrial ecoregions; only the priority conservation areas of the
Global 200 are listed.
See
Global 200 Marine ecoregions for a full list of marine ecoregions (World Wildlife Fund).
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 ecoregions
Freshwater ecoregions are the freshwater habitats of a particular geographic area, including
rivers,
streams,
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.
WWF identifies seven major habitat types of freshwater ecoregions: Large rivers, large river headwaters, large river deltas, small rivers, large lakes, small lakes, and xeric basins.
Several freshwater ecoregions are listed in the
Global 200, the WWF's priority ecoregions for conservation of
biodiversity.
See also
Sources
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.Further Information
Get more info on 'Ecoregions'.
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