What is “riparian vegetation”?
Plants growing on the streambank and adjoining floodplain
Plants in this area are influenced by the water from the stream
Riparian Vegetation Functions
Roots stabilize banks / reduce erosion Provide structure or cover for fish Taller vegetation provides shade Organic food source for aquatic organisms
Leaves Terrestrial insects
Riparian Vegetation Functions
Pollutant filtering Fall into stream – large woody debris
Shapes channel Substrate for biological activity
Relationship to Water Quality
Turbidity / Sediment Phosphorus Temperature (Shade) Nutrient Uptake Nutrient Release (Alder)
Two Ways to Assess a Riparian Zone
Plant Presence Habitat Quality Actual Diversity Invasive Species Changes over time
Riparian Assessment Stability Shade Invasive Species Large Wood
Recruitment Considers non-
vegetative stable substrates
Riparian Assessment
Can be broken into 3 sections: a 100’ riparian transect perpendicular to the
stream, a 100’ “greenline” transect along the stream, a riparian tree count performed in a 100 sq ft
area along the stream
Greenline Transect100ft X 5 ft
FLOW
Pool
Gravel bar
Riffle
Zone 1
Zone 2
Zone 3
Riparian Transect100ft X 10ft
Starting point
Riparian Assessment
Total area = 100 ft x 100 ft (30 m2) Instructions in feet and meters Starting point is at beginning of first
(downstream) habitat unit
Riparian Transect
FLOW
Pool
Gravel bar
Riffle
Zone 1
Zone 2
Zone 3Each zone is 10 meters (33 feet) long
Total transect length = 30 meters (100 feet)
Riparian TransectS
TR
EA
M
Length
11 feet
Width
10 feet
Estimate % cover by 10-20 % increments
May have more or less than 100 feet of “riparian zone”
Greenline TransectS
TR
EA
M
GREENLINE – the first strip of vegetation along the stream
Length
11 feet
Width
5 feet
What Does it Tell Us?
Riparian and Greenline Transects Extent and diversity of riparian zone Stability Invasive species
Riparian Tree Count Age-class diversity Large woody debris recruitment (old growth
conifer, >35”, is MOST desirable)
Evaluation of recruitment
How many trees of varying size are present in the riparian zone?
How close/far are they from the water? Over what time period might they become
available?