Black Lake Integrated Aquatic Vegetation Management Plan. Harry Gibbons Toni Pennington Shannon Brattebo

Transcription

1 Black Lake Integrated Aquatic Vegetation Management Plan Harry Gibbons Toni Pennington Shannon Brattebo 1

2 Benefits of Native Plants Provide diverse habitat for fish & wildlife Competes with algae for nutrients 2

3 Impacts of Aquatic Weeds Impedes water movement Adversely impacts aquatic habitat and water quality Limits recreation Reduces valuable aesthetics Increases evapotranspiration (water loss) 3

4 Aquatic Plants in Black Lake Eurasian watermilfoil (Myriophyllum spicatum) 4

5 Aquatic Plants in Black Lake Yellow iris (Iris pseudacorus) Class C Noxious Weed Counties choose control 5

6 Aquatic Plants in Black Lake White waterlily (Nymphaea odorata) 6

7 Aquatic Plants in Black Lake Slender water-nymph (Najas flexilis) 7

8 Aquatic Plants in Black Lake Spatterdock (Nuphar polysepala) 8

9 Aquatic Plants in Black Lake Non-Native Invasive Species Eurasian watermilfoil (Myriophyllum Spicatum) Yellow iris (Iris pseudacorus) White waterlily (Nymphaea odorata) Slender water-nymph (Najas flexilis) Spatterdock (Nuphar polysepala) Dense shoreline colonies; alters aquatic habitat Dense shoreline colonies; alters aquatic habitat Dense shoreline colonies; alters aquatic habitat May respond to high nutrient availability, accelerate nutrient overenrichment of a water body Native Nuisance Species Response to high lake nutrients Dense colonies throughout lake; alters aquatic habitat; directly impact recreational uses Pros: direct aquatic habitat benefits to fishes and invertebrates; important food source for waterfowl; direct and indirect competition for nutrients versus the cyanobacteria (blue-green algae) Dense shoreline colonies; alters aquatic habitat Pros: provides aquatic habitat; direct food source for aquatic biota Current coverage is not presenting a nuisance relative to the beneficial uses of the lake at this time 9

10 2011 Survey Results Plant Species Est. Acreage Yellow iris 1.6 Waterlily 3.0 Mixed Communities Spatterdock dominant 4.2 Waterlily dominant 27.7 Water nymph dominant 4.8* *Typically found throughout the lake 10

11 Targeted Milfoil Manual Removal Areas 11

12 Management Goals Provide guidance to efficiently and effectively eradicate non-native milfoil, waterlily, and yellow iris from Black Lake Provide for the balanced management of native plants Maximize the beneficial uses of Black Lake Water quality Recreation Fish and wildlife habitat Aesthetics 12

13 Aquatic Plant Control Alternatives No Action Environmental Manipulation Biological Control Manual Control Mechanical Control Chemical Control 13

14 No Action Acknowledges the presence of invasive weeds, but offers no management plan Pros Cons Limited short-term costs at risk of environmental degradation Continued expansion of milfoil in Black Lake and nearby lakes Further degradation and loss of beneficial uses Applicability to Black Lake - None 14

15 Environmental Manipulation Water level control (drawdown) Pros Cons Inexpensive for non-hydropower generating systems Sediment compaction Difficult to establish native plants Future extensive drawdowns may be limited and variable Applicability to Black Lake Limited Insufficient dry and cold conditions Use in combination with other tools 15

16 Biological Control One organism eats another Example: Milfoil weevil Pros Cons Public perception For control, not eradication Restocking required Control unpredictable Applicability to Black Lake - None 16

17 Biological Control Example: Grass carp Pros Cons Public perception Relatively inexpensive Total control or limited control Long-term control (restocking required) Removal difficult and expensive At low stocking rates, spread of less-favored plants (Eurasian watermilfoil) May lead to algae blooms and turbidity All inlets and outlets must be screened to prevent escaping Permitting Applicability to Black Lake - None 17

18 Manual Control Bottom Barrier, hand-pulling and hand-cutting Pros Public perception (visible results and perceived less expensive, but really is more costly) Cons Labor intensive; not as effective if not conducted properly can lead to expansion Applicability to Black Lake Moderate Post-treatment follow-up Use in combination with other tools 18

19 Mechanical Control Machines that cut plants Rotovation Harvesting Diver-assisted suction Hydraulic suction Pros Public perception Cons Not applicable to eradication goals Creates fragments Requires off-site disposal Maintenance Potential Applicability to Black Lake - Limited 19

20 Chemical Control Products licensed by EPA and approved for use by WA Department of Ecology and Thurston County Formulated for applications in or around water Pros Aggressive Whole lake or spot treatments Cons Public perception Applicability to Black Lake - High Can be use in combination with other tools Photo credit: John Madsen Photo credit: John Madsen Photo credit: Terry McNabb, AquaTechnex 20

21 Aquatic Herbicides Approved for Use in Thurston County, WA Active Ingredient Fluridone Trade Names Sonar AS, Avast! SC Sonar PR, Sonar SRP, Sonar Q, Sonar One Target species Milfoil Water nymph Label Water Use Restrictions and Advisories (Ecology) Drinking Swimming Fish Irrigation*** 30 days Glyphosate Rodeo, AquaMaster, AquaPro Waterlily Yellow iris No application within ½ mile of active potable water intake; see label for details Imazamox Clearcast Milfoil Waterlily May be applied up to 500 ppb to within ¼ mile of active potable water intake Not for irrigation until residues < 50 ppb; see label for details Triclopyr Ecotriclopyr, Navitrol DPF, Renovate 3, Renovate OTF Milfoil Waterlily Advisory (Ecology) during treatment and 12 hr posttreatment Not for irrigation for 120 days or until <1.0 ppb; see label for details Endothall Aquathol K, Aquathol Super K Milfoil Water nymph Conditional Use Products in Thurston County Advisory (Ecology) during 7 to 25 days treatment and 24 hr posttreatment 3 days 14 days Imazapyr Ecomazapyr, Gullwing, Habitat, Polaris Waterlily Yellow iris No application within ½ mile of active potable water intake; see label for details Treated water may not be used for 120 days or until 21 <1.0 ppb; see label for details

22 Applicable Tools for Black Lake Combination of Management Tools Manual Mechanical Chemical Timing of Management Multi-year effort Prevention Adaptive Management Evaluation of management methods Long-term surveys of native, non-native and new species 22

23 General Management Approach Multi-year strategy Adaptive and sustainable program Dedicated funding Strong community support Regular reviews of management options Prevention and response measures Diligent monitoring for satellite populations (or pioneering colonies) Control of other non-native species Aquatic plants Zebra mussels New Zealand mudsnails 23

24 Alternative 1: No Action no management activity or planning 24

25 Alternative 2: Long-term Control Continue with current management activities Pros Milfoil control using hand-pulling Expansion of hand-pulling methods to include waterlily and yellow iris Incorporate use of benthic barriers Diver-assisted suction Public perception Cons Long-term effort; may be difficult to meet eradication goal Long-term commitment by residents Expensive due to labor intensity 25

26 Alternative 3: Mid-time Frame Eradication Year 1: Chemical control + manual methods Pre-treatment survey Spring application fluridone to control water nymph Spring application glyphosate to control yellow iris Spring application triclopyr to control waterlily Post-treatment survey Post-treatment hand-pulling Year 2+: Manual methods Early season survey Summer hand-pulling Pros Public perception Cons Less likely to rapidly eradicate invasive weeds 26

27 Alternative 4: Short-term Eradication Year 1: Chemical control + manual methods Pre-treatment survey Spring application fluridone to control water nymph Spring application glyphosate to control yellow iris Spring application triclopyr to control waterlily Post-treatment survey Post-treatment hand-pulling Year 2: Chemical control + manual methods Same as Year 1 Year 3+: Manual methods/chemical control as needed Early season surveys Small infestations (e.g. < 1 acre) = manual methods Large infestations (e.g. > 1 acre) = chemical methods Pros Most rapid approach to achieve goal Cons Multi-year use of herbicide may not be appealing to public 27

28 Management Plan Draft Schedule Aug Sept Oct Nov Dec Jun Vegetation Mapping x Public Meetings 22nd 11th Materials for the Save Black Lake Coalition Website/Newsletter x Draft Black Lake IAVMP submitted to Ecology Respond to Comments Final Black Lake IAVMP submitted to Ecology Apply to Ecology for Aquatic Plant & Algae Management General Permit x x x x Implement Year 1 Recommendations x 28

29 Questions? 29

30 Other Invasive Plants of Concern Hydrilla (Hydrilla verticillata) Class A Noxious weed (eradication required) 30

31 Other Invasive Plants of Concern Curlyleaf pondweed (Potamogeton crispus) 31

32 Other Invasive Plants of Concern Brazilian elodea (Egeria densa) 32