Managing Invasive Species

Invasive Species & Native Habitat

Practical guidance for deciding if, when, and how to manage aquatic invasive species on your shoreline or as a lake community.

Start With a Clear Goal

  • Contain, reduce, or eradicate? Pick one; methods and expectations differ
  • Protect what matters: Swim areas, navigation lanes, native plant beds, fish habitat, or loon nesting
  • Define success: e.g., "Keep ramp area passable all season" or "Reduce milfoil to scattered patches <10% cover"

Confirm the Problem (Before Acting)

  • Describe, don't guess: Record location, depth, extent, and plain-language traits
  • Check for look-alikes: Many natives resemble invaders; mis-ID wastes money and harms habitat
  • Document baseline: Sketch/notes of beds, density, and access impacts

Know the Constraints

  • Permits & rules: Many actions require approval—especially herbicides, dredging, benthic barriers, and work below ordinary high water
  • Neighbors & access: Water moves; fragments and treatments don't respect lot lines. Coordinate across properties
  • Season & weather: Timing is everything; some methods work only at specific growth stages and temperatures

Management Toolbox for Invasive Plants

Best for: New or scattered plants (<1,000 sq ft), early season

Pros: Selective, low cost, minimal permits
Cons: Labor-intensive; fragments can re-root

Tip: Use capture nets and dispose properly

Best for: Moderate patches with rooted invaders where selectivity matters

Pros: Removes roots; selective
Cons: Requires trained crew/equipment; higher cost

Best for: Small, high-use areas (swim lanes, docks) over soft sediments

Pros: Immediate suppression under the mat
Cons: Non-selective; can trap gases; needs maintenance

Best for: Short-term relief of dense surface mats across larger areas

Pros: Restores access quickly
Cons: Non-selective, creates fragments, frequent repeats needed

Best for: Larger infestations or species with proven chemical control windows

Pros: Cost-effective at scale; some products are species-selective
Cons: Permits, trained applicators, water-use restrictions

For Invasive Animals

  • Mussels (zebra/quagga): Focus on prevention, early detection, and containment; whole-lake eradication is rarely feasible
  • Crustaceans & zooplankton: Prevention and gear controls are primary
  • Fish (e.g., common carp): Integrated approaches—barriers, targeted netting/harvest, habitat changes—require professional plans

Choosing Methods: A Simple Flow

  1. Is the infestation small and newly detected? → Hand-pull + containment, reassess in 2–4 weeks
  2. Is it moderate and patchy? → DASH or selective spot treatments; set a monitoring schedule
  3. Is it lake-wide/dense? → Community-scale plan (combination methods, phased treatments, budget + monitoring)

Timing Tips (Plants)

  • Early growth stage = higher success and fewer fragments
  • Pre-flowering/seed set reduces spread
  • Calm conditions help containment and improve treatment precision

Working With Professionals

Ask for:

  • Method rationale
  • Maps of treatment areas
  • Product names and rates (if herbicides)
  • Expected water-use restrictions
  • Monitoring plan

Check references: Seek lakes with similar depth, fetch, and substrate

Plan communication: Post advance notices for neighbors and access users

Safety & Environmental Considerations

  • Avoid disturbing spawning areas, loon nests, and native plant refuges
  • Keep fuel and lubricants out of water; maintain equipment to prevent leaks
  • If using herbicides, follow label directions and all posted water-use restrictions

Handling Fragments & Biomass

  • Contain while working: Use booms/nets down-wind/down-current
  • De-water on land above the high-water line
  • Dispose properly: Compost well away from ditches and wetlands or bag for disposal

Monitor, Then Adjust

  • Post-treatment checks: 2–4 weeks to assess immediate effect; end-of-season to judge regrowth
  • Track effort vs. outcome: Hours, acres, cost, percent cover—compare to your success metric
  • Protect gains: Pair control with prevention at the ramp and shoreline best practices

Budgeting & Sharing Costs

  • Start with a pilot area to gauge effectiveness
  • Combine volunteer labor (hand-pulling, monitoring) with targeted paid work
  • Seek grants or cost-share where available; align schedules to maximize contractor mobilization

Myths—And Better Takes

Myth

"More chemical = faster results"

Better Take

Use labeled rates; more can be illegal and counter-productive

Myth

"Clearing everything makes the lake healthier"

Better Take

Native plants and wood are habitat—be selective

Myth

"Once treated, we're done"

Better Take

Expect follow-up; monitoring prevents rebound and new introductions

Quick Planning Worksheet

Goal: __________________________________________
Target species & extent: __________________________________________
Chosen method(s) & timing: __________________________________________
Permits/approvals needed: __________________________________________
Roles & contacts: __________________________________________
Monitoring dates: __________________________________________

Quick Decision Flow

  1. Small & new? → Hand-pull
  2. Moderate & patchy? → DASH or spot treat
  3. Lake-wide? → Community plan

Related Topics

Key Takeaways

  • Match method to goal and scale
  • Secure approvals before starting
  • Contain fragments during work
  • Monitor results and adjust
  • Pair management with prevention

Before You Start

  • Confirm species ID
  • Check permit requirements
  • Coordinate with neighbors
  • Plan fragment containment

Need Professional Guidance?

Contact your lake association or local natural resources agency for management planning support.

Get Help