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SHR Spatial Scales

Different approaches to rehabilitating regulated rivers exist. All may be organized according to their spatial and temporal scales.

  • Quick local fixes help now to prevent population crashes, but are not sustainable alone over decades and beyond.
  • System changes may some day reap benefits- assuming the underlying science is correct, though most of it remains untested even now- but these broader efforts will not save collapsing populations and food webs to get to that day.
  • Here we focus on the scales relevant to rregulated river reaches downstream of large dams on major rivers with few downstream tributaries.

Hydraulic Unit Microhabitat

0.1 - 10 channel widths

days to years

Provide higher quality habitat for existing populations right now

Geomorphic Unit Mesohabitat

~ 1-10 channel widths

years to decades

Provide greater quantity and diversity of habitats to (i) serve multiple life stages and increase population size and (ii) serve a community of species to protect biodiversity

Reach Macrohabitat

100-1000 channel widths

decades to centuries

Provide a mechanism for self-sustainability of the river system into the future