Ecosystem Restoration Flashcards

Which regulatory framework in the United States requires a Section 404 permit for placement of dredged or fill material in waters of the US, affecting stream and wetland restoration projects?

Answer: Clean Water Act Section 404, administered by the Army Corps of Engineers

CWA Section 404 regulates discharge of dredged or fill material into US waters; restoration projects that place material must obtain or qualify for a nationwide permit.

What is the primary advantage of using passive restoration over active restoration in degraded stream ecosystems?

Answer: It relies on the system's own recovery processes, reducing cost and avoiding construction disturbance

Passive restoration (e.g., fencing to exclude livestock) leverages natural recovery processes at low cost, avoiding soil disturbance that active construction can cause.

A hydrographer calculates a stream power index (SPI) for a restoration reach. Which combination of variables is used in the basic SPI formula?

Answer: Specific catchment area and local slope

Stream power index = specific catchment area × tan(slope), a terrain-based proxy for erosive energy used in landscape-scale restoration site assessment.

In a restored gravel-bed river, what process is termed 'colmation' and why is it a restoration concern?

Answer: Fine sediment clogging of interstitial spaces in spawning gravels, reducing hyporheic exchange and egg survival

Colmation is fine sediment infiltration into gravel interstices that reduces porosity, hyporheic oxygen exchange, and salmonid egg-to-fry survival.

Which metric is used to quantify the degree of hydrologic alteration (DHA) in a restoration project assessment?

Answer: Indicators of Hydrologic Alteration (IHA) comparing pre- and post-development flow statistics

The IHA framework uses 33 ecologically relevant flow statistics to compare altered and reference flow regimes, quantifying the degree and type of hydrologic change.

What does 'functional lift' mean in the context of wetland mitigation banking for ecosystem restoration?

Answer: The measurable improvement in ecological functions provided by a restored wetland compared to its degraded baseline

Functional lift is the net gain in wetland functions (hydrology, biogeochemistry, habitat) from baseline to restored condition, forming the basis for mitigation credit calculation.

When monitoring a restored coastal dune system, which hydrologic measurement best characterizes freshwater lens stability?

Answer: Depth to the freshwater–saltwater interface measured via nested piezometers

Nested piezometers detect the freshwater–saltwater interface depth, indicating whether the restored dune holds sufficient freshwater storage to support dune vegetation.