Monitoring Your Wetland - Macroinvertebrates - Water Resources ...

Monitoring your

Wetland

a primer to site-level monitoring activities for volunteer coordinators

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acroinvertebrates may be small and spineless, but when it comes to the cycling of wetland nutrients there’s nary a niche where you won’t find them. Some, like snails, graze peacefully on aquatic plants, while others, like dragonfly nymphs, voraciously prey on other invertebrates. Sowbugs, caddisfly larvae, clams and other janitorial macroinver tebrates recycle decomposing and particulate matter. Finally, all macroinvertebrates provide food for other wetland animals. Most macroinvertebrates are too small to noticeably stir the water’s surface, but are large enough to see with the naked eye. They include HIGH

RESOURCES

E X P E RT I S E

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LOW

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small worms, mollusks, leeches, crustaceans, insects and insect larvae. Besides Snail playing a star role in many important wetland functions, macroinvertebrates are sometimes employed as a tool for characteriz ing aquatic habitats and learning about aquatic habitat water quality. Macroinvertebrates are sensitive to physical, chemical and biological environmental stressors. And because of their limited mobility, they cannot easily avoid pollution, low oxygen levels or other unfavorable conditions.

About Macroinvertebrate Surveys

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acroinvertebrate monitoring can help characterize wetlands, but as a water quality indicator, wetland macroinvertebrate monitoring has not yet matured. In other aquatic habitats, and particularly streams, macroinvertebrate monitoring has a long history as a tool for assessing water quality. Volunteers who monitor macroinvertebrates in streams look for the presence, absence or dominance of sensitive or tolerant species and then use a biotic index of health to interpret what they indicate about the quality of the stream.

Unfortunately, macroinvertebrate monitor ing in wetlands is much more challenging than in streams. The macroinvertebrate community found in a wetland will differ considerably from the communities in other wetland types. And, because there is a great deal of variation among wetland types, it is difficult to standardize protocol for collecting representative macroinver tebrate samples or identifying a healthy Crayfish or unhealthy macroinvertebrate community. Consequently, it is also difficult to determine when variations in sampled macroinvertebrate

This publication is part of a Monitoring Your Wetland series available online in pdf format at:

wetlandmonitoring.uwex.edu

Bob Korth

Macroinvertebrates . . . . . . . . . .

Jeffrey J. Strobel photos

Monitoring Your Wetland – Benthic Macroinvertebrates

Wetlands alongside a lake

Bog wetland

Wetland with ponds

About Macroinvertebrate Surveys – continued from front page communities are due to wetland degradation or engage your volunteers in if your primary goals natural wetland characteristics. are to raise awareness and characterize the Differences in wetland characteristics wetland. Macroinvertebrate monitoring is a good that have nothing to do with degradation can way to teach volunteers about wetland ecology. influence the presence or absence of various And identifying some of the types of macro species of macroinvertebrates. In contrast to invertebrates living in your wetland contributes shallow, land-locked wetlands, to what you know about it. for example, wetlands connect This publication outlines some Macroinvertebrate ed to lakes or rivers typically basic macroinvertebrate monitoring may be a have fish, which tend to reduce survey methods that can be macroinvertebrate abundance great activity to engage applied to a broad range of and species diversity. Addition wetland types. your volunteers in if ally, naturally high levels of These are methods your primary goals are acidity in bogs can also reduce designed to help maximize to raise awareness macroinvertebrate diversity, but volunteers’ ability to produce and characterize the don’t necessarily indicate poor an inventory of species that wetland. wetland quality. will help characterize a Macroinvertebrate monitor wetland. We will not explain ing is one of the more difficult and costly moni what sampling results indicate about wetland toring efforts a wetland volunteer monitoring health, since methods for doing so are nascent group can engage in. Wetland monitoring even for professional biologists. But for those groups often become frustrated trying to achieve of you interested in experimenting with prelim satisfactory results if they are determined to inary methods for monitoring macroinvertebrates develop a complete inventory of wetland as wetland health indicators, we will briefly macroinvertebrate species or monitor macroin describe and provide references to projects vertebrates as an indicator of wetland quality. testing such methods in Midwestern wetland When trying to monitor macroinvertebrates as areas (see Informational Resources on the indicators, sampling, picking and especially back page). specimen identification can be difficult. All of this having been said, macroinver tebrate monitoring may be a great activity to

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Supplies and Equipment Costs for the equipment, supplies

and need to pick macroinverte

want to experiment with a

and possibly laboratory services

brate specimens from a mat of

number of tools, such as plastic

needed to support macroinverte

duckweed, plant fragments and

spoons, basting brushes or

brate monitoring can range from

muck. White invertebrate

turkey basters.

moderate to high depending on

counting trays made out of fiber

the rigor of the identification

glass or plastic will help volunteers

standards used. Monitoring will,

sort through the mess. Trays

For Identification and Preserving

at minimum, require equipment

used to hold collected samples

for collecting samples. Depending

while volunteers pick specimens

After picking, you will need

on how you structure your volun

out of organic matter should be

teer group’s monitoring activities,

light-weight, flat-bottomed and

they may also need equipment

shouldn’t twist or easily spill.

and supplies for separating

Macroinvertebrate picking trays

specimens from organic matter,

can come in a variety of sizes, but

identification and preserving specimens.

a typical tray might measure 25 cm wide, by 30 cm long and 5 cm deep. Some volunteer groups use

For Collecting Samples

dish pans, which are affordable

Volunteers need at least three

and easy to find.

basic pieces of equipment to gather macroinvertebrate samples. First, they need D-frame macroinvertebrate sampling dip nets and basins or pails for holding samples. Recommended mesh sizes for the sampling nets ranges from 600-1,200 microns. Finer mesh nets will capture more macroinvertebrates, but will also clog easily and can collect an unnecessarily large, debris-laden sample. Finally, because volunteers need to leave dry land to collect samples, they will also need hip boots or waders and possibly a canoe.

For Picking Specimens

To assist in separating organic matter from macroinvertebrate specimens you may also want to provide each volunteer with a framed screen. The screen frame can be made out of wood and the screen can be made out of chicken wire, hardware cloth or other wire mesh with holes big enough for large macroinverte brates to fall through, but small enough to hold back a large quantity of vegetative matter. The screen frame should just fit within the perimeter of a tray and suspend the screen below the lip of the tray and above the tray bottom. You will also need tools for grabbing and removing

When volunteers sample macro

specimens from organic matter,

invertebrates from a wetland

such as forceps and eyedroppers.

they will almost definitely gather

Volunteers may prefer different

a great deal of organic matter

tools for picking and you may

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additional supplies and possibly laboratory services to complete the identification process. For rudimentary identification that can be conducted in the field, volunteers will need a few basic supplies including macroinvertebrate taxonomic keys, ice cube trays for sorting picked macroinvertebrates into families, hand-held magnifying glasses and data recording sheets. For more rigorous identification, volunteers will need access to a laboratory supplied with microscopes. If they are not identifying in the field, they will also need supplies for preserving specimens including vials or bottles to hold macroinvertebrates and a preservative, such as alcohol or glycerin. To obtain the most rigorous identification of sample specimens, volunteer groups will need professional laboratory services. Unfortunately, laboratory services can cost hundreds of dollars and often exceed the resources available to many volunteer monitoring groups.


Volunteers empty a D-frame sampling dip net into containers.

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As little as two to three hours of field training may be sufficient to train volunteers to collect samples. However, picking, and particularly identifying macroinvertebrates, can be very difficult and requires a high level of skill that cannot be taught over a short period of time.

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Survey Participants

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wetland macroinvertebrate monitoring team will require a highly skilled team leader and moderate-to-high skill levels among other volunteers, depending on the design of the monitoring effort. Three tasks must be completed to determine the types and species of macroinvertebrates present in a wetland. Samples must be collected, macroinvertebrates must be picked from the organic matter mixed in the sample and the macroinvertebrates must be identified. Samples must be collected using consistent methods, but volunteers can learn these methods

relatively easily when taught by an experienced instructor. As little as two to three hours of field training may be sufficient to train volunteers to collect samples. However, picking, and particularly identifying macroinvertebrates, can be very dif ficult and requires a high level of skill that cannot be taught over a short period of time. If you ask volunteers to pick and identify specimens, you will need a highly experienced team leader to ensure volunteers are properly picking and to double check identifications. Generally, volunteers are said to struggle with identifying down to the family level.

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Surveying – When, Where & How to Sample

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o get the most representative macroin depths. Depending on how dense the vertebrate sample possible, volunteers vegetation is, volunteers should sample in need to sample at the right time and in the water depths ranging from no deeper than hip right locations. Volunteers don’t need to wake level down to ankle level. In deep water up before dawn or limit monitoring to days with volunteers may find sowbugs, midges and low wind speeds, but they do need to take worms, but macroinvertebrate diversity will be samples at the right time of year. The best low compared with shallow water areas time to sample macroinvertebrates is roughly surrounded by emergent vegetation. from early June through July When taking a sample, or mid-August. Samples volunteers should sweep the Depending on how collected earlier could contain net through the entire water dense the vegetation is, large numbers of under column with a vigorous developed organisms, which jabbing motion, starting near volunteers should will be difficult to identify. the sediment surface. With sample in water depths Sampling is typically each jab of the net, the ranging from no deeper completed before August, volunteer reaches outward than hip level down to since by late summer the and then rapidly pulls toward ankle level. macroinvertebrate community their body with the net, is more likely to include dislodging macroinvertebrates macroinvertebrates that have migrated in from emergent and floating vegetation. When a from connected water bodies and will be less volunteer reaches the water’s surface with their representative of the wetland. Also, in late sample, they should deposit it in a pail. To summer many wetlands can become dry. ensure the pail contains a robust collection of Volunteers can determine where to macroinvertebrates, the volunteer should sample by examining wetland vegetative dipnet one to two more additional samples in composition and water depths. Volunteers the same general area and combine them in the should sample pail with the first. macroinvertebrates These two to three from both emergent samples will be herbaceous plant treated as one communities (the sample when picking underwater portion) and identifying. and submerged and floating aquatic communities when both are present. They should also take samples that represent D-frame dip net, macroinvertebrate key, containers and tools. a range of water

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Surveying – Picking & Preserving

U

nless you send unpicked samples to a lab for identification, volunteers will need to learn how to pick macroinvertebrates from the organic matter scooped up in their dip nets. Even if your volunteers will be sending sampled specimens to a lab for professional identification, your group will likely want to pick the samples first since laboratory fees for unpicked samples are very high. Volunteers should process samples right away while the macroinvertebrates are still moving and easy to see. To pick, volunteers should spread their sample over screens placed inside white picking trays. The macroinverte brates will squirm down toward the bottom of the tray to escape the light and fall through the screen into the tray. Volunteers should let the sample sit for about five to ten minutes while the macroinvertebrates move down.

After allowing the sample to settle for five to ten minutes, the screen and organic matter caught by it can be removed. Before removing the screen, volunteers should inspect it for invertebrates that did not move down into the tray. After removing the tray, volunteers can begin picking. Volunteers should continue to pick either until they have picked 150 specimens from their sample or have been picking for 30 minutes. To avoid picking bias, volunteers should resist the urge to ignore macroinvertebrates that are difficult to pick because they are fast or very small. Volunteers should pick big, small, slow and fast macroinvertebrates. Volunteers should use tweezers or an eye dropper to grab specimens, then drop them into a jar or bottle of water for temporary storage until they can be sorted and/or preserved.

Identification

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hysical features examined to identify those that have casings, some have a case of macroinvertebrates include overall body sticks and others a case of stone. Even with all shape, number and of these possible location of legs, distinguishing features, presence and location macroinvertebrate of gills and tails, the identification is incredi shape of the head bly difficult. capsule and unusual Unless your appendages. volunteers are retired Macroinvertebrate entomologists, they casings and mode of will probably only be locomotion can also able to identify most be used to identify macroinvertebrates macroinvertebrates. down to the order or Some crawl, swim side family taxonomic to side or swim uplevels. Non-expert Sorted macroinvertebrates and identification notes. down. And among entomologists will

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Monitoring Your Wetland – Benthic Macroinvertebrates MACROINVERTEBRATES

Tubifex worm

Tubifex worm: Jason Neuswanger, troutnut.com; scud and black fly: Missouri Dept. of Conservation; mayfly: Dr. Stanley Szczytko, UW-Stevens Point

Scud or sideswimmer

Black fly larva

typically not be able to identify macroinverte brates down to the species or even the genus level. If it is important to you to have a large proportion of sampled macroinvertebrates identified down to the genus or species level and you have substantial resources to support the monitoring project, you might consider sending samples to a professional lab for identification. Laboratories in Stevens Point and at UW-Superior offer identification services. A monitoring project can expect to pay approxi mately $150 in laboratory fees to have a single pre-sorted sample of macroinvertebrate

Mayfly

specimens identified down to the lowest practical taxonomic level, usually genus or species. If you plan to have volunteers identify macroinvertebrates in the field, they’ll need ice cube trays for separating macroinvertebrates into families and macroinvertebrate identifica tion informational resources. Two online identification resources are listed among the Informational Resources on the back page – a guide to macroinvertebrates of the Upper Midwest and a flow chart for identifying common macroinvertebrates found in Wisconsin wetlands.

The Key to Life in the Wetlands flow chart

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Monitoring your

Wetland

a primer to site-level monitoring activities for volunteer coordinators

Macroinvertebrates

. . . . . . . . . . . . . . . . . . . . . . . . . . . INFORMATIONAL RESOURCES Minnesota Pollution Control Agency Macroinvertebrate Community Sampling Protocol for Depressional Wetland Monitoring Sites This document outlines protocol developed for expert-led volunteer monitoring of depressional wetlands in Minnesota. The methods are designed to use macroinvertebrate monitoring as a means of assessing water quality and require identification of macroinvertebrates down to the genus or species level using microscopes. (see website link on wetland monitoring site)

Field Testing the Wisconsin Depressional Wetland Macroinvertebrate and Plant Indices of Biological Integrity for Application by Trained Volunteers This report documents the effectiveness of Wisconsin Department of Natural Resources developed macroinvertebrate and plant biotic index for assessment of isolated depressional wetlands in Wisconsin, when used by DNR biologists not trained in aquatic entomology. (see website link on wetland monitoring site)

The Monitoring Your Wetland series includes 9 sections: • Introduction to Wetland Monitoring • Birds • Small Mammals • Dragonflies & Damselflies (Odonata) • Frogs and Toads (Anurans) • Butterflies (Lepidoptera) • Invasive Plants • Water Quality Macroinvertebrates Available online in pdf format at: wetlandmonitoring.uwex.edu

Great Lakes Coastal Wetlands Consortium Great Lakes Coastal Wetlands Monitoring Plan The fourth chapter of this plan outlines protocol for monitoring macroinvertebrates in Great Lakes coastal wetlands. Requires laboratory identification of macroinvertebrates down to species and genus level. http://www.glc.org/wetlands/final-report.html

Water Action Volunteers Biotic Index This Web page and linked documents are designed to help volunteers monitor macroinvertebrates in streams as part of the Water Action Volunteers program. These guidelines cannot be used to monitor macroinvertebrates in wetlands, but can be used when wetland volunteers monitoring a wetland in which there is a stream would like to monitor the stream. http://watermonitoring.uwex.edu/wav/monitoring/biotic.html

University of Minnesota, Guide to the Aquatic Invertebrates of the Upper Midwest This guide provides an identification key for common aquatic invertebrates found in the Upper Midwest, based on mature larvae or adults. http://wrc.umn.edu/pubs/watersqq/guidetoaquaticinverts

Wisconsin Department of Natural Resources and University of Wisconsin Extension Key to Life in the Wetlands This is a flow chart for identifying common macroinvertebrates found in many Wisconsin wetlands. This chart is handy for identification of macroinvertebrates in the field. http://watermonitoring.uwex.edu/pdf/level3/WEPP/WEPPLifeinWetland.pdf

University of Wisconsin-Superior and University of Wisconsin-Stevens Point Laboratory Identification Services For macroinvertebrate identification contact either UW-Superior Aquatic Entomology Assistant Professor Kurt Schmude, [email protected] (715)394-8421 or UW-Stevens Point Aquatic Entomology Laboratory Supervisor & Research Specialist Jeff Dimick, [email protected] (715)346-3868

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Project coordination by the Rock River Coalition and Suzanne Wade, UW-Extension Basin Education Initiative. Researched and written by Patrice Kohl With editorial contributions from Kurt Schmude University of Wisconsin-Superior assistant professor, aquatic entomology; and Dick Lillie, biologist. Editorial assistance by Marie Martinelle and graphic design by Jeffrey J. Strobel, UW-Extension Environmental Resources Center. Photography by Kris Stepenuck/Citizen Monitoring except where otherwise noted. Project funded through a DNR Citizen-Based Monitoring Partnership Program Grant with support from University of Wisconsin-Extension. University of Wisconsin, U.S. Department of Agriculture and Wisconsin counties cooperating. An EEO/AA employer, University of Wisconsin Extension provides equal opportunities in employment and programming, including Title IX and American with Disabilities (ADA) requirements.