Upland and lowland

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(Redirected from
Lowland
)
For the province of Uppland in Sweden, see Uppland.
"Lowlands" redirects here. For the Low Countries, also known as the Low Lands, see Low Countries.
For other uses, see Lowland (disambiguation) and Upland.
Cascadilla Creek, near Ithaca, New York, in the United States, an example of an upland river habitat

Upland and lowland are conditional descriptions of a

freshwater rivers, habitats
are classified as upland or lowland.

Definitions

Upland and lowland are portions of plain that are conditionally categorized by their elevation above the sea level. Lowlands are usually no higher than 200 m (660 ft), while uplands are somewhere around 200 m (660 ft) to 500 m (1,600 ft). On unusual occasions, certain lowlands such as the Caspian Depression lie below sea level.

Upland habitats are cold, clear and rocky whose rivers are fast-flowing in mountainous areas; lowland habitats are warm with slow-flowing rivers found in relatively flat lowland areas, with water that is frequently colored by sediment and organic matter.

These classifications overlap with the geological definitions of "upland" and "lowland". In

stream terrace
, which are considered to be "lowlands". The term "bottomland" refers to low-lying alluvial land near a river.

Much freshwater fish and invertebrate communities around the world show a pattern of specialization into upland or lowland river habitats. Classifying rivers and streams as upland or lowland is important in freshwater ecology, as the two types of river habitat are very different, and usually support very different populations of fish and invertebrate species.

Uplands

In freshwater ecology, upland rivers and

river bed dominated by bedrock and coarse sediments, a riffle and pool structure and cooler water temperatures. Rivers with a course that drops in elevation very slowly will have slower water flow and lower force. This in turn produces the other characteristics of a lowland river—a meandering course lacking rapids, a river bed dominated by fine sediments and higher water temperatures. Lowland rivers tend to carry more suspended sediment and organic matter as well, but some lowland rivers have periods of high water clarity
in seasonal low-flow periods.

The generally clear, cool, fast-flowing waters and bedrock and coarse sediment beds of upland rivers encourage fish species with limited temperature tolerances, high oxygen needs, strong swimming ability and specialised reproductive strategies to prevent eggs or larvae being swept away. These characteristics also encourage invertebrate species with limited temperature tolerances, high oxygen needs and ecologies revolving around coarse sediments and interstices or "gaps" between those coarse sediments.

The term "upland" is also used in wetland ecology, where "upland" plants indicate an area that is not a wetland.[1]

Lowlands

Amazon River near Manaus, Brazil, an example of a lowland river habitat

The generally more

macrophytes ("water weed").[2]

Lowland alluvial plains

  • American Bottom—flood plain of the Mississippi River in Southern Illinois
  • Bois Brule Bottom
  • Bottomland hardwood forest
    —deciduous hardwood forest found in broad lowland floodplains of the United States

See also

References

  1. U.S. Army Corps of Engineers. Archived
    (PDF) from the original on October 12, 2022. Retrieved October 11, 2022.
  2. ^ Staniszewski, Ryszard; Jusik, Szymon; Kupiec, Jerzy (January 1, 2012). "Variability of Taxonomic Structure of Macrophytes According to Major Morphological Modifications of Lowland and Upland Rivers With Different Water Trophy". Nauka Przyroda Technologie. 6.
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