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Riparian Zone Habitat Assessment. Vegetation and More. 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 Zone. Riparian Vegetation Functions.
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Riparian Zone Habitat Assessment Vegetation and More
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)
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 Two Ways to Assess a Riparian Zone
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
Riparian Transect 100ft X 10ft Zone 3 Zone 2 Zone 1 FLOW Greenline Transect 100ft X 5 ft Riffle Gravel bar Pool 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
Zone 3 Zone 2 Zone 1 FLOW Riffle Gravel bar Pool Riparian Transect Each zone is 10 meters (33 feet) long Total transect length = 30 meters (100 feet)
Riparian Transect Width 10 feet STREAM Estimate % cover by 10-20 % increments May have more or less than 100 feet of “riparian zone” Length 11 feet
Johnson Creek 175 ft
Measure Slope Zone 2 Zone 3 Zone 1 Zone 2 Zone 1 10° 25° 40° 5° 55°
Greenline Transect GREENLINE – the first strip of vegetation along the stream STREAM Length 11 feet Width 5 feet
Zone 3 Zone 2 Zone 1 FLOW Riffle Gravel bar Pool Riparian Tree Count Conifer Deciduous
Tree Size Class Circumference Diameter = Circumference (approx. 3.14) Diameter
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?