ENV SP Natural World & Ecology 3 — Questions and Answers
Question 1: Which of the following best describes a 'trophic cascade' in an aquatic ecosystem?
- Nutrient runoff that fertilizes algae and depletes oxygen
- The indirect effects of apex predator removal on lower trophic levels and vegetation (Correct answer)
- Sequential flooding events that transport sediment downstream
- A waterfall system that oxygenates water at each drop
Correct answer: The indirect effects of apex predator removal on lower trophic levels and vegetation
A trophic cascade occurs when changes at the top predator level ripple down through prey and plant communities, altering overall ecosystem structure.
Question 2: The Envision credit NW1.1 'Preserve Prime Habitat' is most focused on:
- Minimizing land disturbance during construction to protect high-quality ecological areas (Correct answer)
- Installing wildlife crossings to restore connectivity
- Replacing invasive species with native plantings post-construction
- Monitoring groundwater levels to protect aquifer recharge zones
Correct answer: Minimizing land disturbance during construction to protect high-quality ecological areas
NW1.1 targets avoiding or minimizing disturbance to high-quality habitats, particularly those with rare species or ecological significance.
Question 3: In landscape ecology, habitat 'connectivity' is important primarily because it:
- Reduces the need for wildlife management programs
- Allows species to move between patches, supporting gene flow and recolonization (Correct answer)
- Increases plant diversity within a single habitat patch
- Prevents the spread of invasive species across regions
Correct answer: Allows species to move between patches, supporting gene flow and recolonization
Connectivity enables wildlife movement among fragmented habitat patches, sustaining genetic diversity and allowing recolonization after local extinction events.
Question 4: Which water quality parameter is most directly linked to eutrophication in freshwater systems receiving agricultural runoff?
- Dissolved oxygen concentration
- Total phosphorus concentration (Correct answer)
- Water temperature
- pH level
Correct answer: Total phosphorus concentration
Excess phosphorus from fertilizer runoff is typically the limiting nutrient that triggers algal blooms and subsequent eutrophication in freshwater lakes and ponds.
Question 5: The Envision framework credits that address 'Avoid Adverse Geology' are designed to:
- Reduce seismic risk to infrastructure assets
- Prevent destabilization of landforms that could trigger erosion, landslides, or habitat loss (Correct answer)
- Ensure adequate foundation bearing capacity
- Protect against sinkholes in karst topography only
Correct answer: Prevent destabilization of landforms that could trigger erosion, landslides, or habitat loss
These credits focus on avoiding construction activities that destabilize slopes, soils, or geological features in ways that damage natural systems and habitats.
Question 6: An infrastructure team identifies a vernal pool within the project footprint. Vernal pools are ecologically significant primarily because they:
- Provide year-round water supply for surrounding upland species
- Support unique amphibian and invertebrate communities adapted to seasonal flooding and drying (Correct answer)
- Serve as major groundwater recharge areas for municipal wells
- Act as natural sediment traps reducing downstream turbidity
Correct answer: Support unique amphibian and invertebrate communities adapted to seasonal flooding and drying
Vernal pools host specialist species such as obligate amphibians and fairy shrimp that depend on the seasonal wet-dry cycle and the absence of fish predators.
Question 7: According to Envision principles, which approach best demonstrates 'ecological net gain' for a linear infrastructure corridor?
- Installing erosion control blankets on all disturbed slopes
- Designing wildlife crossing structures and revegetating with native species to exceed pre-project habitat quality (Correct answer)
- Planting ornamental trees along the right-of-way for aesthetic benefit
- Using hydraulic seeding to quickly establish vegetative cover
Correct answer: Designing wildlife crossing structures and revegetating with native species to exceed pre-project habitat quality
Ecological net gain requires improvements that demonstrably exceed pre-project habitat quality and function, such as crossings that restore connectivity combined with native restoration.
ENV SP Natural World & Ecology 3
Which of the following best describes a 'trophic cascade' in an aquatic ecosystem?