HomeMy WebLinkAbout2024 Mill Pond Point Intercept Survey Report2024 Mill Pond (DOW: 27004100, Hennepin County)
Aquatic Vegetation Point Intercept Survey Report
6/7/2024
An aquatic vegetation point intercept survey was completed in Mill Pond on 6/7/2024 for the City of
Edina to help determine the impacts of monthly mechanical harvester use on invasive and native
communities.
A total of 22 species were sampled during the survey. 17 native species were collected comprised
of 11 submerged species, 4 floating species, and 2 emergent species (See table 1). 5 invasive
species were collected comprised of 2 submerged species and 3 emergent species (See table 1).
The point intercept survey consisted of 74 points. At each site depth was recorded and vegetation
was sampled with a double-sided rake. For every species sampled, an abundance rating was
assigned based on how much was sampled on the rake. The ratings are as follows:
0. Plant species absent
1. Plant species covers <25% of the rake
2. Plant species covers 25-75% of the rake
3. Plant species covers >75% of the rake
It was also noted if a plant species was in the study area as a visual observation.
This rating scale was taken out of the Minnesota Department of Natural Resources Guidance for
Delineating Aquatic Plants for Management.
Table 1: Vegetation species sampled in Mill Pond on 6/7/2024. The table notes the number of sites where each species
were sampled on the rake, frequency of occurrence, average rake abundance, and visual observations.
Vegetation Species Sites Sampled
on Rake
Frequency Of
Occurrence
Average Rake
Abundance
Visual
Observations
Submerged Species
Coontail 50 67.6 2.2 6
Water Stargrass 1 1.4 1.0 2
Elodea canadensis 24 32.4 1.9 4
Sago Pondweed 7 9.5 1.4 5
Horned Pondweed 1 1.4 1.0 0
Fries Pondweed 4 5.4 1.8 5
White Crowfoot 0 0.0 4
Flatstem Pondweed 25 33.8 1.7 4
Leafy Pondweed 11 14.9 2.5 4
Longleaf Pondweed 5 6.8 2.2 8
Forked Duckweed 0 0.0 1
Floating Species
White Water Lily 8 10.8 1.8 20
Large Duckweed 2 2.7 2.0 12
Small Duckweed 5 6.8 1.6 10
Watermeal 0 0.0 1
Emergent Species
Eleocharis acicularis 0 0.0 1
Iris versicolor 0 0.0 1
Invasive Species
Curlyleaf Pondweed 47 63.5 2.5 6
Eurasian Watermilfoil 33 44.6 1.6 2
Iris pseudacorus 0 0.0 2
Purple Loosestrife 1 1.4 1.0 0
Narrow Cattail 1 1.4 2.0 0
Discussion
Based on the results of the survey the most upstream and downstream reaches of the pond were
more diverse in terms of total richness and site richness. Further investigation into the total area
harvested of the mechanical harvester could reveal these reaches are not in the harvester’s path
leaving these communities unimpacted. The middle reach of the pond was characterized by a
greater abundance of nuisance plants like coontail, curlyleaf pondweed, Eurasian watermilfoil, and
Elodea canadensis. The plants are more advantageous to fill disturbed areas.
Based on previous surveys from PI Charter, common bladderwort was not sampled during the 2024
survey.
Site Richness Map
Figure 1. 2024 Mill Pond site richness. Every site had at least one species of vegetation sampled. The highest site richness
was 10 species.
Distribution and Abundance Maps
Figure 2. 2024 Mill Pond coontail distribution and abundance. Coontail was found at the most sites.
Figure 3. 2024 Mill Pond curlyleaf pondweed distribution and abundance. CLP was found at the second most sites.
Figure 4. 2024 Mill Pond Eurasian watermilfoil distribution and abundance.
Figure 5. 2024 Mill Pond flatstem pondweed distribution and abundance.
Figure 6. 2024 Mill Pond common waterweed distribution and abundance.
Figure 7. 2024 Mill Pond leafy pondweed distribution and abundance.
Figure 8. 2024 Mill Pond sago pondweed distribution and abundance.
Figure 9. 2024 Mill Pond fries pondweed distribution and abundance.
Figure 10. 2024 Mill Pond longleaf pondweed distribution and abundance.
Figure 11. 2024 Mill Pond horned pondweed distribution and abundance.
Figure 12. 2024 Mill Pond water stargrass distribution and abundance.
Figure 13. 2024 Mill Pond white crowfoot distribution and abundance.
Figure 14. 2024 Mill Pond white water lily distribution and abundance.
Figure 15. 2024 Mill Pond yellow iris distribution and abundance.
Figure 16. 2024 Mill Pond narrow cattail distribution and abundance. Purple loosestrife and needle spike rush were
exclusively sampled at the same site. PLSF and NSR only had a rating of 1.