Monitoring 3 Flashcards
Urban environments often have surface runoff issues. What are the causes of this flashiness and what are some solutions for reducing runoff and increasing water retention?
Erosion resulting from:
1) Loss of plant cover
2) Increased soil compaction/impermeable surfaces
3) Loss of roots/SOC
Solutions:
1) Increase interception - plants, leaf litter
2) Green manure - tilling cover crops into soil greatly increases water retention
3) Grass waterways - shallow out water channel, plant grass to intercept runoff, filter and prevent gullies.
4) Rain Gardens - deep rooted native plants, filters, intercepts, increases infiltration
In arid regions, some invasive woody species will outcompete natives causing shortages of water through increased transpiration. How would you deal with this situation?
Solution:
Remove woody species by harvesting, cutting, burning, Will likely still need to use herbicide to prevent reestablishment.
What are some problems and solutions associated with altered ground hydrology? (ditches, ground tiles)
Drainage systems dewater sites, increasing O2 concentrations and often have excess nutrients from fertilizers.
Solution: Ditches and tiles should be disabled. Just plugging the drainage is enough.
Pretend you have a stream that is downcutting. What are the problems with this and some methods for restoration to mitigate it?
Increasing grade, increases flows and velocity. Two probems:
1) Erosion and down cutting.
2) Reduces habitat area from braided to channelized
Solution: Grade controls like rock vortex weirs. This reduces erosion, increases sedimentation and creates more habitat for wildlife
What processes are affected through the disconnecting wetlands from floodplains? What are some potential solutions?
Regular flooding is important for:
1) Sediment and nutrient transport.
2) Flood plains help reduce flooding downstream
3) Filter water.
Solution: Remove dams and dikes. Often run into legal troubles.
What are some of the benefits and drawbacks of dike removal?
Increased habitat area for native species. Braiding of estuaries, dispersal of more nutrients and sediments.
Increases risk of storm surge, might change habitat features of species that have been accustomed to the new environment.
How do invasive species outcompete native vegetation? What is impacted and how do you manage these invasive species?
Competition for resources. Often have adaptations that allow for nitrogen fixing or C4 photosynthesis pathways. Results in
1) Reduction of biodiversity
2) Habitat structure - native fauna
3) Ecosystem function is altered
Solution:
1) Cover crops to shade invasive/reduce erosion/provide temperature buffers for native plants.
2) Use animals to graze or browse.
*What are the 3 pathways bioremediation uses to remove contaminants from a site?
1) Volatilization - Gas and gone
2) Plant accumulation (remove and dispose)
3) Soil and plant biodegradation (breaking it down)
What are some of the limitations of bioremediation?
Need to know how deep the contaminants go. Roots or microbes can only go to a certain depth.
Some absorbed contaminants can be left in place for mulch/fuel/compost unless they are toxic, then they must be removed and disposed of.
What are some veg and soil prep techniques to favour native plant species?
1) Reduction of non-native plants through removal
2) Alterations of soil:
- Increase SOC (green manure)
- Reduce acidity (lime, ash, oyster shell)
- Reduce alkalinity (sulfur, org. matter, rehydrating)
- Reducing compaction (deep rooted species, cultivators, subsoilers)
Note: soil amendments are additions to soil to alter physical properties.
Ensure plant species are well-suited for the soil conditions.
What are some tools and techniques for reducing woody vegetation and providing more light to understory plants?
Mechanical - Cutting, Girdling
Chemical - Herbicide
Burns
Tools: Brush Hogs, Root rakes.
Mechanical and chemical often have to be used in tandem.
How does prescribed burning help to create favourable conditions for native species?
1) Plants that have evolved with fire will win out.
- Fire stimulated germination
- Reducing woody veg and creating wildlife trees
2) Altering chemistry
- Releasing nutrients
- Reducing acidity through ash
What two (often conflicting) criteria are prescribed burns generally conducted to accomplish?
What are the consequences of this?
1) Matching historical fire regimes in terms of intensity, frequency, extent,
2) Ensuring conditions are met with regards to human safety ex low wind, temperature, moisture.
This means that fires often differ from historical regimes. Fires seasons should therefore be changed to have burns to multiple seasons to reduce potential for ecological harm. This would also reduce the stress associated with fire managers having to burn a lot of sites in one season.
