Common Restoration Techniques Flashcards
What are the 5 categories of restoration techniques that managers use?
Hydrological techniques Biological techniques Site preparation Woody vegetation control Prescribed burning
What are the 4 hydrological restoration techniques we discussed?
Water interception and retention
Restore hydrology
Grade control
Reconnect waterways
Issue 1: increased runoff and erosion due to loss of vegetation, compaction, reduced infiltration, interception, and storage/retention (5 points)
Solution: increase water retention by,
- Using cover crops
- Using green manure
- Creating grass waterways
- Planting rain gardens and deep rooted native plants
Cover crops
A hydrological restoration technique that involves planting vegetation to increase water interception and reduce erosion
Green manure
Hydrological restoration technique that involves tilling cover crops into soil to increase soil organic matter and thus water retention
Grass waterways (2 points)
Natural drainage is graded and shaped to form a shallow channel then planted with sod-forming grasses.
This grass then intercepts runoff, filters sediment/nutrients/contaminants from fields, prevents gullies from forming and provides habitat for animals
Benefits of rain gardens and planting deep-rooted native plants
Intercepts run off, filters contaminants and nutrients, and increases infiltration in areas with high impenetrable cover
Issue: in arid ecosystems, invasive woody vegetation can reduce water retention through increased rates of transpiration (4 points)
Solution: remove invasive woody plants by:
- harvesting
- brushing
- herbicide
- prescribed fire
Issue: drainage systems dewater sites to improve conditions for crops. The resulting changes in nutrients and decreased oxygen in soils disfavour many native plants
Solution: disable ditches and tiles to restore underground hydrology
Issue: channelization and gradient increase to streams in order to de-water channels. This increases erosion, downcutting, and removes natural features for animal/plant habitat (4 points)
Solution: grade control
Build grade control structures such as rock vortex weirs and low-drop grade control structures
They can be natural or artificial
They are barriers that produce reduced gradient in streams and direct flows to the centre of the stream bed
Issue: dams and dykes have reduced flood frequency, disconnecting flood plains from their stream channel (removing maintenance disturbance regime) (4 points)
Solution: remove or breach dams and dykes
Often a legal rather than a practical challenge
Flood events will build up their own natural dykes with the flood process
Some issues might occur at the onset before natural dykes are built up (eg. Flooding of buildings etc. near area)
Hydrological issues that managers focus on (4 points)
Leaky watershed (high run-off, erosion and sedimentation)
Woody plants increasing transpiration
Dewatered sites from drainage systems
Channelization and gradient increases in streams
What are the 3 biological restoration techniques we discussed?
Cover crops
Animals
Bioremediation
What are biological restoration techniques?
The use of plants, animals, and other living organisms to achieve restoration ends
Reducing invasive/non-native plants can be achieved using: (3 points)
Cover crops to reduce erosion, shade invasives (smother crops) and protect slower growing natives from freezing and rapid drying (nurse crops)
Animals can be used to remove invasives/non-native plants that are herbaceous (grazing) or woody (browsing)
Bioremediation (2 points)
The use of living organisms to consume and break down contaminants
This often entails using microorganisms but can entail using rapidly growing plants called phytoremediation
What can bioremediation be used to do? (2 points)
Absorb contaminants - if organic, can later be used as mulch, if toxic, can later be disposed of
Increase soil organic matter and stability - enables soils to tie up contaminants
What aspects of ecosystems are affected by disturbance regimes such as fire? (3 points)
Species composition
Structure
Ecological processes
How does fire affect ecosystems? (2 points)
Through altering the successional stage
Through altering the chemistry
How does fire alter the successional stage of an ecosystem? (3 points)
Reduces fire intolerant species (those not adapted to fire regime=non-natives)
Stimulates germination of fire adapted species
Reduces woody vegetation while creating wildlife trees (standing dead wood) or coarse woody debris (dead and down trees)
How does fire alter the chemistry of an ecosystem? (2 points)
Releasing nutrients in vegetation
Reducing soil acidity
Prescribed burns are generally conducted according to 2 conflicting criteria: (3 points)
Matching historical fire regimes (in terms of frequency, severity, size, and patchiness)
Ensuring conditions are conductive to human safety (low wind/temperature, high moisture)
Human safety often takes precedent
How do we avoid the conflicts between matching historical fire regimes and human well-being? (3 points)
We do prescribed burning at various times of year (not just in the wet season)
This allowed us to increase the potential for desirable outcomes and prevent danger as managers are more selective in choosing safe conditions
Also, they are not forced to do all their burning in one season and can therefore have smaller, more manageable fires even if the hot season
What are the 2 site preparation techniques we discussed?
Reduction of invasive/non-native species using mechanical, chemical, or prescribed burning techniques
Soil modification
What is the purpose of site preparation techniques?
To alter the conditions to favour native species of plants
What are the soil amendments in site preparation? (4 points)
Increasing OM (eg. Green manure)
Reducing acidity (eg. Applying lime)
Reducing alkalinity (eg. Applying sulfur)
Reducing compaction (eg.planting deep-rooted species, subsoiling)
What are some techniques to remove woody vegetation? (4 points)
Prescribed burning (encroachment and competition)
Chemical removal
Mechanical removal like harvesting, brushing, girdling
Note: mechanical removal is often followed by chemical removal
