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Ecological integrity The ability of the river corridor to support and maintain a
community of organisms with species composition, diversity, and functional
organization similar to those within natural habitats in the same region
Ecoregion A relatively large area of land or water that contains a geographically
distinct assemblage of natural communities
Ecosystem A community of living organisms linked together and to the adjacent
environment through fluxes of nutrients and energy
Ecosystem services Include the categories of provisioning (products obtained
from ecosystems), regulating (benefits obtained from the regulation of ecosystem processes), supporting (services necessary for the production of all other
ecosystem services), and cultural (non-material benefits that people derive from
ecosystems)
Environmental flow Can refer to a specific flow release, such as an experimental
flood release from a dam, or to an annual hydrograph that specifies magnitude,
frequency, timing, duration, and rate of change in flow
Equilibrium A change to inputs or controlling parameters will result in a proportional change in the river corridor
Feedback Describes adjustments among components of a river ecosystem; positive or self-enhancing feedback occurs when an initial change creates a cascade
of subsequent changes that amplify the initial change; negative or self-arresting
feedback occurs when an initial change is dampened by the response of the river
corridor
Floodplain That portion of the valley bottom inundated by water overflowing the
channel banks during peak flows that occur every year or every few years
Flood-pulse model Describes the ecological influence of the seasonal flood pulse
on large floodplain rivers such as the Amazon; water, sediment, nutrients, and
organisms move from the channel onto the floodplain during peak flood flow and
then return to the main channel and secondary channels during the receding limb
and base flow
Flow-pulse model Flow pulses are fluctuations in discharge that change the extent
of flow and standing water within a braided or anabranching channel segment;
model emphasizes the ecological importance of these fluctuations
Hierarchical patch dynamics Characterizes river corridors as consisting of
relatively homogeneous patches from the scale of microhabitat up to channel
reaches, with distinct changes in process and form between patches
Hot moment Short period with disproportionately high biogeochemical reaction
rates relative to longer intervening periods
Hot spot Patch with a disproportionately high biogeochemical reaction rate relative to the surrounding matrix
Hyporheic zone The area below the channel and floodplain in which flow paths
originate from and terminate in the channel
Hypoxia Occurs when dissolved oxygen levels are < 2 mg per liter, commonly as
a result of excess nutrients that lead to high primary production and then decay
of organic matter
Glossary
Ecological integrity The ability of the river corridor to support and maintain a
community of organisms with species composition, diversity, and functional
organization similar to those within natural habitats in the same region
Ecoregion A relatively large area of land or water that contains a geographically
distinct assemblage of natural communities
Ecosystem A community of living organisms linked together and to the adjacent
environment through fluxes of nutrients and energy
Ecosystem services Include the categories of provisioning (products obtained
from ecosystems), regulating (benefits obtained from the regulation of ecosystem processes), supporting (services necessary for the production of all other
ecosystem services), and cultural (non-material benefits that people derive from
ecosystems)
Environmental flow Can refer to a specific flow release, such as an experimental
flood release from a dam, or to an annual hydrograph that specifies magnitude,
frequency, timing, duration, and rate of change in flow
Equilibrium A change to inputs or controlling parameters will result in a proportional change in the river corridor
Feedback Describes adjustments among components of a river ecosystem; positive or self-enhancing feedback occurs when an initial change creates a cascade
of subsequent changes that amplify the initial change; negative or self-arresting
feedback occurs when an initial change is dampened by the response of the river
corridor
Floodplain That portion of the valley bottom inundated by water overflowing the
channel banks during peak flows that occur every year or every few years
Flood-pulse model Describes the ecological influence of the seasonal flood pulse
on large floodplain rivers such as the Amazon; water, sediment, nutrients, and
organisms move from the channel onto the floodplain during peak flood flow and
then return to the main channel and secondary channels during the receding limb
and base flow
Flow-pulse model Flow pulses are fluctuations in discharge that change the extent
of flow and standing water within a braided or anabranching channel segment;
model emphasizes the ecological importance of these fluctuations
Hierarchical patch dynamics Characterizes river corridors as consisting of
relatively homogeneous patches from the scale of microhabitat up to channel
reaches, with distinct changes in process and form between patches
Hot moment Short period with disproportionately high biogeochemical reaction
rates relative to longer intervening periods
Hot spot Patch with a disproportionately high biogeochemical reaction rate relative to the surrounding matrix
Hyporheic zone The area below the channel and floodplain in which flow paths
originate from and terminate in the channel
Hypoxia Occurs when dissolved oxygen levels are < 2 mg per liter, commonly as
a result of excess nutrients that lead to high primary production and then decay
of organic matter
Glossary