CWD Wetland Functions & Values 1 — Questions and Answers
Question 1: Which primary function do wetlands perform by temporarily storing excess stormwater and releasing it slowly downstream?
- Sediment trapping
- Flood attenuation (Correct answer)
- Denitrification
- Groundwater recharge
Correct answer: Flood attenuation
Wetlands act as natural sponges that temporarily store floodwaters and release them slowly, reducing downstream peak flows and flood damage.
Question 2: Which microbial process in wetland soils converts nitrates to nitrogen gas, permanently removing nitrogen from the aquatic system?
- Nitrification
- Ammonification
- Denitrification (Correct answer)
- Nitrogen fixation
Correct answer: Denitrification
Denitrification is the anaerobic microbial process that converts nitrates (NO3-) to nitrogen gas (N2), which escapes to the atmosphere and removes nitrogen from the system.
Question 3: The Hydrogeomorphic (HGM) approach to wetland functional assessment classifies wetlands primarily based on:
- Dominant plant community type and structure
- Soil taxonomy and horizon development
- Geomorphic setting, water source, and hydrodynamics (Correct answer)
- Regulatory jurisdiction and permit status
Correct answer: Geomorphic setting, water source, and hydrodynamics
The HGM approach classifies wetlands by their geomorphic setting, water source, and hydrodynamics to predict functional capacity relative to reference wetlands of the same class.
Question 4: Carbon sequestration in wetlands is most significant in which type of system due to slow organic matter decomposition under anaerobic conditions?
- Tidal salt marshes
- Peatlands such as bogs and fens (Correct answer)
- Seasonal vernal pools
- Freshwater emergent marshes
Correct answer: Peatlands such as bogs and fens
Peatlands accumulate carbon-rich peat over millennia because waterlogged, anaerobic conditions dramatically slow decomposition, making them the largest terrestrial carbon stores per unit area.
Question 5: Coastal wetlands such as salt marshes and mangroves support marine fisheries primarily by:
- Filtering saltwater to create freshwater nursery zones
- Serving as critical spawning grounds and nursery habitat for juvenile fish (Correct answer)
- Producing algae that serves as the sole food source for fish
- Creating physical barriers that protect adult fish from ocean predators
Correct answer: Serving as critical spawning grounds and nursery habitat for juvenile fish
Salt marshes and mangroves provide structure, cover, and abundant invertebrate prey that make them essential spawning and nursery habitat for many commercially and recreationally important fish species.
Question 6: What is the fundamental difference between a wetland 'function' and a wetland 'value'?
- Functions are ecological processes; values represent human-assigned worth of those processes (Correct answer)
- Functions are measured monetarily; values are measured in acreage
- Functions apply to freshwater systems only; values apply to coastal systems
- Functions are regulated by EPA; values are regulated by the Army Corps of Engineers
Correct answer: Functions are ecological processes; values represent human-assigned worth of those processes
Wetland functions are the physical, chemical, and biological processes wetlands perform (e.g., denitrification), while values represent the human benefit or worth assigned to those functions (e.g., cleaner drinking water).
Question 7: In the HGM classification system, which wetland class receives its water and nutrients almost exclusively from precipitation with negligible surface or groundwater inputs?
- Riverine
- Depressional
- Slope
- Organic soil flat (Correct answer)
Correct answer: Organic soil flat
Organic soil flats (bogs) are ombrotrophic systems that receive water and nutrients exclusively from precipitation, isolated from surface water and groundwater inputs.
CWD Wetland Functions & Values 1
Which primary function do wetlands perform by temporarily storing excess stormwater and releasing it slowly downstream?