Volunteer Monitoring:
Invasive Aquatic Plant
Survey Manual
Tier One
Written by: Elizabeth M. Herron
Hope Leeson
Linda Taylor Green
Contribution #5118 of the College of the Environment and Life Sciences, University of Rhode Island, United
States Department of Agriculture, and local governments cooperating. Cooperative Extension in Rhode
Island provides equal opportunities without regard to race, age, color, national origin, sex or sexual
preference, creed, or handicap
Volunteer Monitoring:
Invasive Aquatic Plant Survey Manual
Tier One
By
Elizabeth M. Herron
Hope Leeson
Linda Taylor Green
Department of Natural Resources Science
University of Rhode Island
Kingston, Rhode Island
July 1994, Revised July 2007, July 2009 and July 2011
Elizabeth M. Herron is a Research Associate III and Linda Taylor Green is a Research
Associate IV and in the Department of Natural Resources Science. Hope Leeson is a
Botanist with the Rhode Island Natural History Survey, and a veteran of the URI
Watershed Watch program.
University of Rhode Island Watershed Watch
(URIWW) Invasive Aquatic Plant Survey Manual
Tier One
Table of Contents
I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
II. Recognizing plant form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A. Submergents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B. Floating-leaved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C. Free Floating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D. Emergents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
III. Survey schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IV. Choosing survey locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A. Aquatic plant bed assessment . . . . . . . . . . . . . . . . . . . . . . . . .
B. Survey location selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C. Collecting optional survey location information. . . . . . . . . . . . .
V. Filling out the "Aquatic Plant Tag". . . . . . . . . . . . . . . . . . . . . . . . .
A. Location information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B. Plant site depth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C. Recording bottom type (substrate) . . . . . . . . . . . . . . . . . . . . . .
D. Recording plant abundance. . . . . . . . . . . . . . . . . . . . . . . . . . .
E. Collecting Voucher Specimens. . . . . . . . . . . . . . . . . . . . . . . . .
VI. Making an aquatic plant bed assessment. . . . . . . . . . . . . . . . . .
VII. What to do with the completed survey. . . . . . . . . . . . . . . . . . . . .
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example Aquatic Plant Tag. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Example Invasive Aquatic Plant Survey Form . . . . . . . . . . . . . . . . . .
Notes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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University of Rhode Island Watershed Watch
(URIWW) Invasive Aquatic Plant Survey Manual
Tier One
I. Introduction
Macrophytes:
larger rooted
aquatic plants.
littoral zone:
shallow areas
where sufficient
light reaches
the lake bottom
to promote
photosynthesis
in rooted plants.
Aquatic plants serve a critical role in lake and river
ecosystems. Macrophytes provide food for waterfowl and wildlife,
protect small fish and create spawning habitats, act as refuges for
zooplankton, and oxygenate water. They reduce erosion by
providing bottom stability and diminishing wave action. Macrophytes
also play a crucial role in nutrient transport to and from sediments.
They can be found throughout the littoral zone.
Figure 1. Features of the littoral zone
While plants are important to the overall ecology of a
waterbody, the proliferation of some species can be unhealthy. Of
particular concern are the exotic, or non-native plants which can
frequently crowd out native aquatic plants. They can become
nuisances primarily because there are no natural controls to their
growth. A lack of predators or pathogenic organisms allows exotics
to out-compete native species for growing space, light, and nutrients.
Shoreline and bottom disturbance can affect native plant
communities, making it easier for exotic species to become
established. Excess nutrients from runoff and other sources can
also lead to overgrowth of both native and exotic species. Aquatic
1
plants are referred to as "weeds" when they are a non-native
species, or a native species growing in such abundance that the use
and enjoyment of recreational waters is impaired.
Improved understanding of aquatic plants and the role they
play in lake and river ecosystems is essential to the proper
management of freshwater bodies. By mapping and monitoring
aquatic plants it can often be determined which areas may be
sensitive to runoff and disturbance. It is important to watch for
problems in plant communities (such as the introduction of exotics
and the loss of plant diversity) that may be warning signals for the
entire lake ecosystem. It is equally useful and quite rewarding to
observe improvements (such as re-establishment of native species
or an increase in species diversity) that may result from lake and
watershed management activities.
In order to determine if, or when, to manage plants, knowledge
of their abundance and distribution is necessary. While an extensive
plant survey may be necessary in some cases, often a semiquantitative assessment can provide a great deal of information,
particularly knowing whether non-native plants are present. The
purpose of this particular protocol, the first tier of aquatic plant
monitoring, is to determine whether invasive species are present, a
process trained volunteers can easily perform. With increased
training, volunteers can map the general distribution of aquatic plant
beds, determine the relative abundance of various plants in specific
beds, identify common plant species, and also collect difficult to
identify species for professional identification. That level of training
and effort will be the next tier of aquatic plant monitoring, and the
subject of later protocols.
The following non-native aquatic plant monitoring protocol has
largely been adapted from the Wisconsin Department of Natural
Resources Aquatic Invasives Handbook as well as drawing on (and
contributing to) materials from the Maine Center for Invasive Aquatic
Plants, New Hampshire Department of Environmental Services,
Connecticut Sea Grant, Invasive Plant Atlas of New England
(IPANE), Rhode Island Natural History Survey (RINHS) and Rhode
Island Department of Environmental Management (RIDEM). The
protocol was designed to obtain baseline data on aquatic plant
distribution, and the extent to which, non-native invasive aquatic
species are present in Rhode Island. The protocol can be easily
adapted to rivers by addressing them in manageable segments.
2
II. Recognizing plant form
Life-form:
the
physical
structure
or growth
habit of a
plant
Aquatic plants can basically be divided into groups based on
their life-forms. Height, branching pattern and leaf shape all
contribute to form. The form that a plant has affects how it functions,
and where it may grow in a lake. Various plant forms impact
recreational and wildlife usage differently.
A. Submergents
The life-form "submergent" refers to plants that grow entirely
beneath the water surface. Some species in this group may have
flowers that extent above the water. Most submergents are rooted to
the bottom. Common submergent species in Rhode Island include
Cabomba caroliniana (fanwort – non-native), Ceratophyllum
demursum (coontail) or Utricularia radiata (bladderwort).
Cerotophyllum demursum
B. Floating-leaved
Plants that are rooted to the bottom with leaves that float on
the water surface, are of the "floating-leaved" life-form. Species in
this group generally have flowers that are above water. Nymphaea
ordorata (white water lily), Potamogeton epihydrus (ribbonleaf
pondweed) and Brassenia schreberi (water-shield) are floatingleaved species common in Rhode Island.
Nymphaea ordorata
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C. Free Floating
The "floating" life-form refers to plants that are not rooted to
the bottom, that float freely on the surface. Plants in this group are
generally very small. Species in the Genus Lemna (duckweed) may
be found in Rhode Island.
Lemna minor
Not to scale
D. Emergents
Herbaceous:
plants with a
fleshy rather
than woody
stem
The life-form "emergent" refers to rooted herbaceous or
semiwoody plants that have the majority of their vegetative parts
above the surface of the water. Emergent plants may be found in
areas where the water is several feet deep, up to where the
lakeshore is only sporadically flooded or moist. Emergents take a
variety of sub-forms. Juncus militaris (bayonet rush), Lythrum
salicaria (purple loosestrife – non-native), and Typha latifolia (broadleaf cattail) are examples of common Rhode Island emergent
species.
Typha latifolia
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III. Survey schedule
Surface:
includes
both freefloating and
floatingleaved
plants
While macrophyte communities in New England experience
significant seasonal fluctuations, there is little variation on a daily
basis. Therefore, an aquatic plant survey can be completed over a
period of up to two weeks if necessary. Emergent and surface plant
beds may be surveyed at any time of the day, provided there is
adequate light. Submergent plant beds should be surveyed during
the period when sunlight penetration is greatest, between 10 AM and
2 PM, the same as for Secchi depth determination.
Aquatic plant surveying and mapping are best completed
between mid-July and late August when nearly all of southern New
England's macrophyte species are in full growth. This is also the
period when many species are in bloom, which makes it easier to
correctly identify species which may otherwise appear similar.
The two exceptions to this time period would be a survey for
the non-native invasive Curly pondweed (Potamogeton crispus), or
the Inflated bladderwort (Utricularia inflata) which are visible from
early in June to the beginning of July. By mid-July Curly pondweed
goes dormant, until the much smaller winter buds are visible
beginning in mid to late August. The flowering structure of the
Inflated bladderwort (the wheel) also passes by mid-July, leaving
only the underwater portion of the plant, making it extremely difficult
to differentiate from the native species. A quick survey in June to
determine if Potamogeton crispus or Utricularia inflata are present
will provide valuable information on the extent of those species in
Rhode Island.
IV. Choosing survey locations
A. Aquatic plant bed assessment
Ideally, survey locations should be selected at sufficient
intervals to construct a map of plant coverage throughout the littoral
zone. However, time constraints may prevent volunteers from
performing such an in-depth survey. In order to ensure that the
species distribution of a lake's major aquatic plant beds are mapped,
a preliminary assessment should be performed. In this assessment,
the volunteer paddles or cruises around the perimeter of the lake in a
zigzagging pattern throughout the littoral zone (typically out to a
depth equal to or slightly deeper than the maximum water clarity or
Secchi depth transparency) marking the location of emergent,
5
submergent, floating-leaved and free-floating plant beds on a map of
the lake. Note the depth at which emergent plants give way to
submergents completely. Step by step instructions for completing an
aquatic preliminary assessment are in section VI.
If available, a bathymetric map should be used. Fisheries
Bathymetric:
Investigation and Management in Rhode Island Lakes and Ponds,
depth
published by the Rhode Island Department of Environmental
contour
Management (Guthrie and Stolgitis, 1990), has bathymetric maps for
lines
101 Rhode Island ponds (URI Watershed Watch can print you a
copy if your waterbody is one of those). Lake maps copied from
United States Geological Survey topographic maps are also very
useful as they may have landmarks already noted, and are readily
available. When bathymetric maps are not available, topographic
maps can be useful for estimating the lake bottom contours. For
example, if there is a steep slope running down into a lake, you
might expect that the lake bottom would also have a steep slope. If
the surrounding lands are relatively flat, you would expect the lake to
have similarly gentle contours. Finally, lake maps can also be
copied from road maps or produced from online mapping services if
necessary.
Use a lake map which is large enough to draw in the plant
beds and to code plant types and species. Remember to include
some indication of map scale. The scale printed on an original map
(i.e. “1 inch equals 20 feet”) may not apply to an enlarged copy. In
such a case, you should write in the approximate distance between
two known points as a reference. For example, if you have enlarged
a section of a road map, try to keep some perimeter roads on your
copy. You can then write in that it is "1 mile from Maple St. to Brown
St.", drawing in the 1 mile line. This becomes a reference for
determining approximate distances and areas (Figure 2).
Figure 2. Map with reference marks
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B. Survey location selection
A survey location is an area where you stop to collect and
attempt to determine if the plants found there are invasives. The
priority of this survey is to determine the presence or absence of
non-native invasive aquatic plants, so survey site selection should
focus on areas where non-native plants are most likely to be. In
particular, boat launch ramps and fishing piers have been shown to
be common starting places of new infestations. Plant fragments may
be attached to boat trailers or included with discarded bait,
introducing new species. Therefore initial efforts should focus on
aquatic plant beds near these features, and other sites with
suspected invasive species. At least one survey location should be
situated in each of the major plant beds identified on the preliminary
assessment map if possible.
If it is not possible to survey each of the major plant beds, the
areas in which sediment and nutrients are concentrated, such as an
outlet or inlet, boat launch sites, marinas, and other shallow areas
should be mapped. Areas which are also of specific interest to the
volunteer, such as an association beach, a favorite fishing cove, or
bed of atypical plants, should also be included.
In the event that you find a plant that you suspect is an
invasive species, a voucher specimen should be collected, along
with the geographic and survey information needed to complete the
Aquatic Plant Tag (copies can be downloaded as a pdf from
http://www.uri.edu/ce/wq/ww/Aquatic-Plant-Tag.pdf).
If you do not have a range finder to determine distances from
the shoreline, you can use the length of your boat or canoe to help
you estimate that. For example, if you have a 12 foot canoe, you
can determine how many canoe-lengths from shore you are, then
multiply the number of canoe lengths by 12. If you have access to a
GPS (global positioning system) unit, you can record actual latitude
and longitude for your survey sites. Water depth can be determined
with a Secchi disk or a weighted line marked at intervals. Electronic
depth (fish) finders can help you accurately survey the depth.
C. Collecting optional survey location information
While it is not necessary, photographing the area between
each survey location and the shore can be very useful. This
provides a visual record of the emergent plant communities that can
be compared with photographs taken in the future. By recording the
survey location information on the back of the photograph, and cross
7
referencing it with the survey information sheet, it becomes even
more valuable.
Completing an Invasive Aquatic Plant Survey Form for each
waterbody or river segment surveyed would provide valuable
information on where invasive species are, but also document areas
where they may not yet be present. Protecting waterbodies that
have not yet been “invaded” protects critical habitat and is much
more cost-effective and likely to be successful, than trying to manage
the plants once they are established. An Invasive Aquatic Plant
Survey Form, which can be downloaded as a pdf from
http://www.uri.edu/ce/wq/ww/Aquatic-Plant-Survey-Form.pdf,
includes information about the extent of your survey and a listing of
invasive plants that you found. A map of your waterbody marked
with where you found the various invasive species should be
included with your survey form.
Conducting a shoreline survey of the natural and manmade
features of the lake or river shore can provide some insight into the
distribution of aquatic plants. Information regarding how to conduct a
shoreline survey may be obtained through URIWW.
V. Filling out the "Aquatic Plant Tag
A. Location information
Fill out an Aquatic Plant Tag for each suspected invasive plant
you find during your survey (as opposed to the survey form which
should be completed for each waterbody surveyed – whether you
find invasive species or not). Each form must be properly identified
with the volunteers' names, the name and town (remember there are
several Deep Ponds in Rhode Island) of the waterbody being
surveyed, and the date of the survey. Latitude and longitude of the
waterbody is very useful for reducing confusion, and can be found
with a GSP, online or from a topographic map. A lake map with the
location of the plant associated with the plant tag is also essential for
later confirmation.
When describing the specific location where a plant was found, try to
find two landmarks with which to align your collection site, noting the
landmarks on the form and a map if possible. When possible, these
landmarks should be "permanent" features such as identifiable
boulders, bridges or buildings, rather than trees or shrubs which may
easily be removed or destroyed. If you have a GPS, please also
record the latitude and longitude of the exact location where you
collected the plant associated with that form. This information should
8
be detailed enough to allow the site to be re-assessed in the future.
The landmarks should also be recorded on a lake map (Figure 3).
Figure 3. Sample map with landmarks and location of suspected
invasive plants noted
For each site where you find a potentially invasive plant, the following
conditions should be assessed.
B. Plant Site depth
Determine the depth at which the samples are taken with a
Secchi disk, a weighted measuring tape or depth finder. Record that
information for each type of plant found in the appropriate spaces.
C. Recording bottom type (substrate)
Record the dominant bottom type by circling the most
appropriate choice. Typical bottom compositions are: muck, mud,
sand, gravel and rock.
• Muck is very high in organic material of a loose consistency, or
"oozy",
• Mud is a mixture of organic material and sand,
• Gravel includes smaller rock forms ranging from pebbles to
cobbles, and
• Rock is exposed bedrock, more or less solid, with or without
boulders.
The bottom sediments may not be visible due to leaves or other
debris. In that case, record that debris was present. If possible, use
a rake to remove some of the debris to identify the bottom condition.
9
D. Recording plant abundance
Was the plant found only in a single area or plant bed in the
lake, (Single patch) or did you note a few sprigs of it in various areas
in the lake (Sparsely throughout)? If the plant was found in large
numbers in a few discrete areas, that would be described as
“Multiple patches”. If the plant seemed to be found throughout much
of the lake in large numbers then select “Densely throughout”.
E. Collecting Voucher Specimens
Contacts:
found in
the
reference
section
If you encounter a non-native aquatic plant species in your
survey (or are unsure of a species identity, and suspect that is in an
invasive species), please submit a voucher specimen for
confirmation or identification by the URIWW, the (RINHS), or the
Wood Pawcatuck Watershed Association (WPWA) following these
steps.
Collect a section of the plant that contains all representative leaf
types, this may mean that several sections need to be collected.
Most species have a combination of underwater (submerged) leaves
and above water (emergent) leaves and/or flowering structures. It is
also important to collect representative flower or seed structures if
possible, as they are often crucial for correctly identifying a plant.
Flowers may be inconspicuous as they are often very small and may
be somewhat hidden by being located where a leaf attaches to the
stem.
A photograph of the species’ population, or the area of the plant bed
where it is was found, would be very helpful. A photo could provide a
sense of the population density and overall health.
Gently rinse all debris and dirt from the plant and its root structure (if
you were able to collect the root). Place the cleaned specimen in a
sealed plastic bag with enough tap water to keep the plant moist.
Keep the bagged plant refrigerated until you can deliver it to the URI
Watershed Watch laboratory, or one of the partner organizations.
Be sure to complete an Aquatic Plant tag with each voucher
specimen. Advance notice that voucher specimens will be brought in
will be needed in order to ensure that program staff are available to
either promptly identify or properly store them. Several dates and
times designated specifically for identifying plants have been set-up,
and those dates will be printed on the Survey Form each season.
10
VI. Making an aquatic plant bed assessment
Equipment checklist
For a safe
and
successful
assessment:
conduct
preliminary
aquatic plant
bed mapping
when there
is adequate
light and little
boating
activity.
Items needed for conducting a preliminary assessment of aquatic
plants:
_____
clip board and pencil
_____
clean map of the lake (bathymetric if possible)
_____
Secchi disk, weighted measuring tape or depth finder
_____
polarized sunglasses
_____
view bucket or goggles (optional)
_____
weighted sampling rake with line attached to handle
(can be an ordinary rigid tine garden rake)
_____
aquatic plant identification key
_____
pictorial plant guide
_____
clear plastic bags with zip closures
_____
permanent ink pen ("Sharpie") for marking bags
_____
buckets or coolers for storing bags of plants
_____
anchor
1. Mark the following information on your lake map: Lake, Date,
Volunteer(s), and any additional observations.
2. Motor or paddle around your lakeshore (or survey area) in a
zigzagging pattern out to a depth where you can’t see the bottom
or any plants growing once to get a sense of the plant beds.
3. Stopping frequently for closer looks, circle the lakeshore again.
Note the plant beds and the plants growing there. Photograph
emergent aquatic plant beds, with reference landmarks or other
location information if possible. Collect and attempt to identify
any plants that look as though they are invasive species. Keep a
voucher specimen of any plant that you confirm as invasive or are
concerned about, placing it in a labeled plastic bag (more detailed
voucher preparation can be done shoreside or at home).
4. Using a Secchi disk, weighted measuring tape or depth finder,
determine the lake depth at the sites where you collected plants,
mark the depth on the plastic bag.
5. Complete an Aquatic Plant Tag for each plant collected.
The survey need not be completed on a single day. Remember,
please dispose of all plant material in the trash or compost it,
DO NOT RETURN IT TO THE LAKE.
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VII. What to do with the completed survey
When you have finished your survey, you may wish to re-draw your
maps or copy the information onto fresh survey forms, especially if they got
wet. Please make at least one copy of the final maps and survey forms,
and return it to the URIWW office. Your local lake association or
conservation commission may also be interested in receiving copies. You
should keep a copy for yourself so that you can watch your lake for
changes that could indicate problems, or just keep track of it as it slowly
and naturally ages.
References:
Golet, Francis, C. and Joseph S. Larson. 1974. Classifications of
Freshwater Wetlands in the Glaciated Northeast. U.S. Department
of the Interior, Fish and Wildlife Service, Bureau of Sport Fisheries
and Wildlife. Washington, D.C.
Lamb, Bonnie, Arthur J. Gold, Calvin P. Poon, and Christopher Deacutis.
1991. Southern Rhode Island Water Quality Assessment Program:
Final Report. University of Rhode Island, Natural Resource
Sciences Department.
McComas, Steve. 1994. Lakes Smarts: The First Lake Maintenance
Handbook-A Do-It-Yourself Guide to Solving Lake Problems.
Terrene Institute. Washington, D.C.
New York Department of Environmental Conservation, Division of
Water, Lake Services Section and New York Federation of Lake
Associations. 1994. New York Citizens Statewide Lake
Assessment Program: Sampling Protocol.
Prescott, G.W. 1980. How to Know the Aquatic Plants. Wm. C. Brown
Company Publishers. Dubuque, Iowa.
Tempte, Jo. 1994. Aquatic Plant Monitoring Procedures: A Self-Help
Lake Volunteer Training Manual. Wisconsin Department of Natural
Resources.
Contact information:
URI Watershed Watch: Room 002, Coastal Institute in Kingston, 1
Greenhouse Rd, Kingston, RI 02881; Phone: 401-874-2905 or
401-874-4552; email: [email protected]
RI Natural History Survey: Room 200, Ranger Hall, Kingston, RI 02881;
Phone: 401-874-5800, email: [email protected]
Wood-Pawcatuck Watershed Association: 203 Arcadia Road, Hope Valley,
RI, 02832; Phone: 401-539-9017, email: [email protected]
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Notes:
15