Aquatic Plant Identification Focus on Aquatic Weeds

144 Pages·2012·24.87 MB·English

by  Authorized User

Aquatic Plants
Continuing Education Session
Elizabeth Brown
Invasive Species Coordinator
Colorado Parks and Wildlife

March 26, 2012
Jackson, WY
Aquatic Plants Overview
 Session Agenda
Identification

• Floating
• Submerged
• Emergent
Survey Methods

Management / Control Options

Additional Resources

True aquatic plants are defined as plants that

are normally, comDpleetefliyn ori tmioostnly ssu bmerged in
water and are unable to survive for long periods
outside that medium. This definition includes
floating, as well as rooted aquatic species.
• MN DNR “A Guide to Aquatic Plants”
Aquatic Nuisance Species (ANS) are defined as

fish, animal and plant species that have been
introduced into new ecosystems throughout the
USA. These exotic species are having harmful
impacts on natural resources and the human use
of these resources.
• ANS Task Force
“On a global basis…the two great destroyers of
biodiversity are first, habitat destruction and
second, invasion by exotic species”
E.O. Wilson
Types of Aquatic Plants
Aquatic macrophytes
Role of Aquatic Plants
benefit the system as:
• A source of dissolved oxygen (O )
2
• A sink for Carbon Dioxide (CO )
2
• Bank, bed and shoreline protection
•Habitat for macroinvertebrates and fish
• Food for waterfowl and animals
• Nutrient cycling and slowing of sediment transport
Why Are Native Aquatic Plants
Plants are the foundation of life that without other organisms

Good For Fish?
can’t survive.
Plants keep the water oxygenated, provide food, cover and

nesting sites and stabilize the shoreline and bottom.
Most fish don't actually eat aquatic plants; instead, they eat

other organisms--microscopic animals, aquatic insects, crayfish
and frogs--that either eat plants themselves or live on or
around them.
Beds of vegetation give young fish a place to hide from

predators. Without such escape cover, few would survive long
enough to grow to a larger size.
Aquatic plant beds also provide good fishing spots, because

they attract adults of most fish species.
How Many Plants Are Too Many?
Depends on the water body size and type of

fishery.
There should be a narrow band of underwater

and emergent plants around much of the water's
edge. These plants will stabilize the shoreline and
attract fish from deeper water.
~10-20% cover in ponds and small lakes

~10-30% cover in larger lakes and reservoirs

Literature varies – Know Your Site!

When Do Too Many Plants
Exotic, No Predators, Invasives!

Become A Problem?
Excessive aquatic vegetation may cause…

• Fish kills– oxygen depletion from large plant beds (as
sunlight decreases, plants use more oxygen than they
produce or decaying plants utilizing oxygen to break down)
• Alteration of the balance of the fish community by
providing too much escape cover for young fish
• Alteration of the spawning mechanisms in deeper waters
• Physical interference with the intended use of a lake or
pond, such as boating, swimming, fishing, irrigation or
livestock watering.
Maintaining the balance of
 The Goal
beneficial native aquatic plant
species to support fisheries,
waterfowl, other wildlife and
recreational opportunities.