memo Project Name Spider Lake Point Intercept Survey 2017 Date 9/5/17 To / Contact info Jerry Spetzman Cc / Contact info Greg Graske, PE

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1 memo Project Name Spider Lake Point Intercept Survey 2017 Date 9/5/17 To / Contact info Cc / Contact info From / Contact info Regarding Jerry Spetzman Greg Graske, PE Joe Pallardy, Mike Majeski Spider Lake Aquatic Plant Community Spider Lake Survey Results A point-intercept aquatic plant survey was completed on August 7, 2017 at Spider Lake. The pointintercept method is considered the standard protocol by MnDNR for sampling macrophytes because it offers a methodology that is quantitative (e.g., frequency of occurrence), repeatable (can be used to track trends in aquatic plant communities over time), and georeferenced (can be used to compare plant communities within different areas of a lake). From this data, a Floristic Quality Index (FQI) was calculated that measures the diversity and health of the aquatic plant community. The FQI calculation is based on both the quantity of species observed (species richness) as well as the quality of each individual species. Every aquatic plant in Minnesota has been assigned a coefficient of conservatism value (c-value) ranging from 0 to 10. The c-value of all aquatic plants sampled from a lake is used to determine the FQI for a given lake. Species with a c-value of 0 include non-native species such as curly-leaf pondweed (Potamogeton crispus) that are indicative of a highly disturbed environment. In comparison, the native species Oakes pondweed (Potamogeton oakesainus) has a c-value of 10 because this species is extremely rare and only found in undisturbed, pristine environments. The average FQI score for Minnesota Lakes in the North Central Hardwood Forest (NCHF) ecoregion is 23.7±8 with a median of 22.5 (Radomski and Perleberg, 2012). A study of 41 Minnesota lakes surveyed across the state, as part of the EPA s National Lakes Assessment Project, yielded a maximum FQI score of 30. In 2016, the MNDNR developed a robust geodatabase of aquatic plant surveys and associated FQI scores from more than 3,600 lakes across the state. FQI scores ranged from 0 to 49 with a median of 25.1±9. Included in Table 2 is a list of all native aquatic plants sampled and their associated c-values and frequency of occurrence values. Error! Reference source not found. includes introduced species which have been assigned a c-value of 0. FQI scores from the MN DNR geodatabase exclude introduced species from their FQI calculation; therefore, Table 2 provides the best means of comparison with the DNR geodatabase. Error! Reference source not found. is useful in that introduced species are both an indication of anthropogenic stress and a stressor themselves in terms of their direct impact to the surrounding plant community. The FQI score of for Spider Lake was slightly higher than the median FQI score for assessed lakes in the DNR geodatabase and the NCHF ecoregion average. The FQI score for Spider Lake is reflective of the lake s high quality near-shore aquatic plant community which contained several high quality emergent plant species including blue flag iris (Iris versacolor), sessile-fruited arrowhead (Sagittaria rigida), and softstem bulrush (Schoenoplectus tabernaemontani). The near-shore aquatic plant community is directly correlated with the largely intact nature of the riparian buffer surrounding Spider Lake. EOR is an Equal Opportunity Affirmative Action Employer Emmons & Olivier Resources, Inc th Street N. Oakdale, MN T/ F/

2 Observed water clarity within Spider Lake has improved considerably over the past 5 years (personal communication, Jerry Spetzman). As the water clarity has improved, the macrophyte community has responded as sunlight was able to penetrate further into the water column, thus supporting macrophyte growth at greater depths. A healthy macrophyte community can help to maintain a clear-water, macrophyte-dominated state which is the ecologically preferred state. The results of the Spider Lake survey are summarized in Table 2. Included in the table is a list of aquatic plants sampled and their associated c-values and frequency of occurrence values. The distribution and density ranking for each individual species with a frequency of occurrence 5% is mapped within Appendix A. For each data point mapped, a density ranking of 1 indicates only a few individual plants were observed while a ranking of 4 indicates an abundance of plants were observed.

3 Table 1. Spider Lake Point-Intercept Survey Results- Native Species Only. Common Name Scientific Name C- Value Frequency of Occurrence Bladderwort (Common) Utricularia vulgaris 7 5.6% Blue flag iris Iris versicolor 4 5.0% Broad-leaf arrowhead Sagittaria latifolia 3 9.4% Broad-leaf cattail Typha latifolia 2 0.6% Buttercup Ranunculus sp % Canada waterweed Elodea canadensis % Coontail Ceratophyllum demersum % Fern-leaf pondweed Potamogeton robbinsii % Flatstem pondweed Potamogeton zosteriformis 6 9.4% Floating pondweed Potamogeton natans 5 4.4% Giant bur-reed Sparganium eurycarpum 5 4.4% Greater duckweed Spirodela polyrhiza 5 8.1% Large-leaf pondweed Potamogeton amplifolius % Lesser duckweed Lemna minor 5 4.4% Needle spikerush Eleocharis acicularis 4 1.9% Northern watermilfoil Myriophyllum exalbescens 7 1.9% Sessile-fruited arrowhead Sagittaria rigida 7 8.1% Small pondweed Potamogeton pusillus 7 0.6% Softstem bulrush Schoenoplectus tabernaemontani % Star duckweed Lemna trisulca 5 6.9% Water celery Vallisneria americana 8 1.3% Water smartweed Polygonum amphibium 4 0.6% White water-lily Nymphaea odorata % Yellow pond-lily Nuphar lutea ssp. pumila 9 5.0% Summary Table FQI = C* S C= Mean coefficient of conservatism value S= Number of species in sample Average C-Value 5.42 Number of species 24 FQI 26.54

4 Table 2. Spider Lake Point-Intercept Survey Results w/ Introduced Species. Common Name Scientific Name C- Value Frequency of Occurrence Bladderwort (Common) Utricularia vulgaris 7 5.6% Blue flag iris Iris versicolor 4 5.0% Broad-leaf arrowhead Sagittaria latifolia 3 9.4% Broad-leaf cattail Typha latifolia 2 0.6% Buttercup Ranunculus sp % Canada waterweed Elodea canadensis % Coontail Ceratophyllum demersum % Curly-leaf pondweed* Potamogeton crispus 0 0.7% Fern-leaf pondweed Potamogeton robbinsii % Flatstem pondweed Potamogeton zosteriformis 6 9.4% Floating pondweed Potamogeton natans 5 4.4% Giant bur-reed Sparganium eurycarpum 5 4.4% Greater duckweed Spirodela polyrhiza 5 8.1% Large-leaf pondweed Potamogeton amplifolius % Lesser duckweed Lemna minor 5 4.4% Needle spikerush Eleocharis acicularis 4 1.9% Narrow-leaf cattail* Typha angustifolia 0 6.9% Northern watermilfoil Myriophyllum exalbescens 7 1.9% Sessile-fruited arrowhead Sagittaria rigida 7 8.1% Small pondweed Potamogeton pusillus 7 0.6% Softstem bulrush Schoenoplectus tabernaemontani % Star duckweed Lemna trisulca 5 6.9% Water celery Vallisneria americana 8 1.3% Water smartweed Polygonum amphibium 4 0.6% White water-lily Nymphaea odorata % Yellow pond-lily Nuphar lutea ssp. pumila 9 5.0% Summary Table FQI = C* S C= Mean coefficient of conservatism value S= Number of species in sample *Invasive Species Average C-Value 5.0 Number of species 26 FQI 25.49

5 Appendix A: Spider Lake Aquatic Plant Species Distribution Figure 1. Curly-leaf pondweed abundance and distribution August, 2017.

6 Figure 2. Flatstem pondweed distribution and abundance August, 2017.

7 Figure 3. Coontail distribution and abundance August, 2017.

8 Figure 4. Canada waterweed distribution and abundance August, 2017.

9 Figure 5. Yellow pond-lily and white water-lily distribution and abundance August, 2017.

10 Figure 6. Fern-leaf pondweed distribution and abundance August, 2017.

11 Figure 7. Softstem Bulrush and Blue Flag Iris distribution and abundance August, 2017.

12 Figure 8. Narrow-leaf (T. angustifolia) and Broad-leaf (T. latifolia) Cattail distribution and abundance August, 2017.

13 Figure 9. Broad-leaf and Sessile-Fruited Arrowhead distribution and abundance August, 2017.

14 Figure 10. Duckweed species distribution and abundance August, 2017.

15 Figure 11. Common Bladderwort distribution and abundance August, 2017.

16 Figure 12. Large leaf Pondweed distribution and abundance August, 2017.