Discovery Park Ecosystem Services
Discovery Park MGIS Capstone 2018 Vegetation Monitoring and Mapping Project
Sample Plot weed indexes give native species a numeric rank of 1, a nonnative non-
invasive species a numeric rank of 3, and an invasive plant species numeric rank of
5. Aggregated sample plot weed index scores close to one indicate low weed
influence and weed index scores close to 5 indicate high weed influence. This
index reflects how well native plant species are doing in competition with
nonnative plants.
Other Resources
Discovery Park Predicted Weed Index Surface
Discovery Park Ecosystem Services
The Discovery Park Weed Index
Browse Discovery Park Ecosystem Services Vegetation Monitoring and Mapping Web Pages
The Discovery Park Vegetation Monitoring and Mapping Website Main Page
The Discovery Park Credit /Debit Calculator
The Discovery Park Moisture Index Surface
The Discovery Park Plant Community
The Discovery Park Bird Use of Plant Community
The Discovery Park Worldwide Web Map
Calculating a Sample Plot Weed Index
The table below demonstrates how a weed index for a plant sample plot is calculated. The percent cover of each species in the sample plot is multiplied by their respective weed indexes to derive a weighted percent cover. Both the percent cover and weighted percent cover columns are totaled. Then the total weighted percent cover is divided by the total unweighted percent cover (270 / 220) to derive the sample plot weed index of 1.23
Example Sample Plot 2 Weed Index Calculation
Species
Percent Cover
Weed Index
Weighted Percent Cover
Oemleria cerasiformis
1
1
1
Ilex aquifolium
<
1
3
3
Hedera helix
<
3
5
15
Rubus spectabilis
<
75
1
75
Polystichum munitum
<
7
1
7
Thuja plicata
<
20
1
20
Rubus armeniacus
<
7
5
35
Unknown moss
<
3
1
3
Lysichiton americanus
<
20
1
20
Oenanthe sarmentosa
<
15
1
15
Alnus rubra
<
40
1
40
Equisetum telmateia
<
4
3
12
Pteridium aquilinum
<
10
1
10
Urtica dioica
<
10
1
10
Athyrium filix femina
<
4
1
4
Totals:
<
220
270
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Hypothetical Wetland Mitigation Bank Management Unit A Credit Release Based on One Component (Weed Index 1 = low, 2 = med. low, 3 = med. high, 4 = high) of Vegetation Performance - based on assumption of Credit Value at $75,000.00
WeedClass
WIndexRange
Acres
PotCredits
Penalty
AvaiCredits
CreditValue
1
1 – 2
18.91
9.455
0
9.455
$709,125.00
2
2 – 3
11.14
5.57
0.25
4.1775
$313,312.50
3
3 – 4
3.56
1.78
0.50
0.89
$66,750.00
4
4 – 5
0.71
0.355
0.75
0.08875
$6,656.25
Total
34.32
17.16
14.61
$1,095,843.75
John Marshall
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