Excerpt from Maine Field Guide to Invasive Aquatic Plants
© 2008 Maine Volunteer Lake Monitoring Program
BACKGROUND
PLANT COMMUNITIES
Most aquatic plants are found in the near
shore portions of the waterbody where
sunlight penetrates to the bottom sediments.
This portion of the lake, pond or stream is
called the littoral zone. As water clarity and
the bathymetry vary widely from one
waterbody to another, the outer depth of the
littoral zone also varies. The plants that grow
in the littoral zone can be conceptually
grouped into distinct communities. In reality,
however, there is a good deal of overlap
between communities.
EMERGENT PLANT COMMUNITY: This area
extends from the wet shoreline soils into
relatively shallow (knee-deep) water. With stiff
but buoyant leaves and tough interlocking
roots, emergent plants are well adapted to
life at the water’s edge where wave action
and fluctuating water levels are common. The
plants in this community play an important
role in protecting water quality by preventing
shoreline erosion and the resuspension of
fine bottom sediments. They also provide
important food and cover for insects, fish
and waterfowl. Native plants commonly
found in the emergent plant community
(also referred to as “wetland” plants) include:
cattails, arrowheads, pickerel weed, sedges
and rushes.
Emergent Plant
Community
Though there are invasive emergent plant species that threaten Maine’s
wetlands, none is currently prohibited by law as are the eleven aquatic
plants on Maine’s invasive aquatic plant list. Information on three of
these invasive wetland species is presented on page 123.
FLOATING-LEAVED Plant Community: This area extends from
the wet shoreline to chest deep water. Plants in this group are
distinguished by tough, waxy leaves adapted to float on the surface
of the water. Some floating-leaved plants have long, elastic leaf stalks
extending to the bottom sediments. Others are free-floating. Native
plants commonly found in this community include: fragrant waterlilies,
watershield, spatterdock, and little floating heart. Three of the eleven
invasive aquatic plants on Maine’s list are found in this community:
European frogbit, yellow floating heart, and water chestnut.
Maine Volunteer Lake Monitoring Program
Littoral Zone
Major Plant Communities of Lakes and Ponds
Floating-leaved
Plant
Community
Submersed Plant
Community
PLANT COMMUNITIES
Excerpt from Maine Field Guide to Invasive Aquatic Plants
© 2008 Maine Volunteer Lake Monitoring Program
Deep Water
SUBMERSED Plant Community: This area extends from the shallowest
depths to the deepest waters of the littoral zone. Plants in this community
are adapted to life below the water surface, though many produce emergent or floating flowers that appear at or above the surface later in the
growing season. Native plants found in this community may include:
coontail, bladderworts, pondweeds, and the native water-milfoils. Eight of
the eleven invasive aquatic plants on Maine’s invasive aquatic plant list
are found in this community: Brazilian waterweed, curly-leaf pondweed,
Eurasian water-milfoil, European naiad, fanwort, hydrilla, parrot feather,
and variable water-milfoil.
Maine Volunteer Lake Monitoring Program