Biology & Ecology of SE MN Karst Region StreamsMacroinvertebrate Ecology & Bioassessments

Natural History of Stream

Invertebrates: Making Sense of

Biotic Indices

Segment 2 Outline

Roles and types of aquatic macroinvertebrates

Habitats, feeding, life histories, and tolerance

Biological integrity and its application in southern MN

Freshwater Ecology

Physical

Biological Chemical

light

currenttemperature

substrate

pH

DO

[nutrients]

alkalinity

photosynthesis

macroinvertebrates

macrophytes

fish

The Importance of Macroinvertebrates• Macroinvertebrates are an

essential component of freshwater ecosystems

• They serve as food for other organisms (fish, amphibians and waterfowl)

• Are essential to the breakdown and cycling of organic matter and nutrients

• Macroinvertebrate diversity is vital to a properly functioning ecosystem

Why Study Macroinvertebrates?• Macroinvertebrates are

used to assess the health of freshwater environments

• Some macroinvertebrates are sensitive to stress produced by pollution, habitat modification, or severe natural events

• Sampling and identifying macroinvertebrates can reveal whether a body of water is healthy or unhealthy and may reveal the cause of the problem

Why are macroinvertebrates biological indicators

of stream health?

Spend up to one year (or more) in the stream

Have little mobility Generally abundant Primary food source for

many fish Good indicators of local

conditions Diversity = healthy stream Easy to sample

Adult Caddisfly

Stream Benthic Macroinvertebrates: Standard Habitat Samples from Iowa Streams

Common MacroinvertebratesMayflies (Ephemeroptera)

Baetidae

Ephemerellidae Heptageniidae Isonychiidae

(Adult)

Common MacroinvertebratesStoneflies (Plecoptera)

PerlidaePteronarcydiae

Perlodidae(Adult)

Common Macroinvertebrates

Brachycentridae

Phryganeidae Hydropsychidae

Philopotamidae

Caddisflies (Trichoptera)

Case (Adult)

Common Macroinvertebrates

Damselflies and Dragonflies (Odonata)

True Bugs (Hemiptera)

Dobsonflies, Alderflies and Fishflies

(Megaloptera)Beetles (Coleoptera)

Common Macroinvertebrates

Midge (Chironomidae)

Cranefly (Tipulidae)Midge adult

True Flies (Diptera)

Blackfly (Simuliidae)

Common Macroinvertebrates

Crayfish and Amphipods(Crustacea)

Snails/Mussels (Mollusca)

Worms and Leeches(Oligochaeta)

Planarians (Platyhelminthes)

Macroinvertebrate Biology

Habitat

Movement

Feeding

Life History

Stress Tolerance

Use in Biomonitoring

HabitatThe place where an organism lives

Running waters – lotic – seeps, springs, brooks,

branches, creeks, streams, rivers

Mineral bedrock, boulders, cobbles, pebble,

gravel, sand, silt, clay

Standing waters – lentic – bogs, marshes, swamps, ponds, lakes

erosional (riffles, wave action) or depositional areas (point bars,

pools)

Organiclive plants,

detritus

Movement

Clingers – maintain a relatively fixed position on firm substrates in current

Climbers – dwell on live aquatic plants or plant debris

Crawlers – have elongate bodies with thin legs, slowly move using legs

Sprawlers – live on the bottom consisting of fine sediments

Burrowers – dig down and reside in the soft, fine sediment

Swimmers – adapted for moving through water

Skaters – adapted to remain on the surface of water

Locomotion, habits, or mode of existence

FeedingMacroinvertebrates are described by how

they eat, rather than what they eat

Functional Feeding Groups – categories of

macroinvertebrates based on body structures and behavioral mechanisms that they use to

acquire their food

Shredders

• Material is usually >1 mm, referred to as Coarse Particulate Organic Matter (CPOM)

Chew on intact or large pieces of plant material

Shredder-herbivores feed on living aquatic plants that grow submerged in the water (northern casemaker caddisflies)

Shredder-detritivores feed on detritus, or dead plant material in a state of decay (giant stoneflies)

Collectors

Collector-filterers- use special straining mechanisms to feed on fine detritus that is suspended in the water

Acquire and ingest very small particles (<1 mm) of detritus, often referred to as fine particulate

organic matter (FPOM)

Collector-gatherers – eat fine detritus that has fallen out of suspension that is lying on the bottom or mixed with bottom sediments

Piercers

Piercer-herbivores – penetrate the tissues of vascular or aquatic plants or individual cells of filamentous algae and suck the liquid contents (crawling water beetles, microcaddisflies)

Piercer-predators – subdue and kill other animals by removing their body fluids

mouthparts, or sometimes their entire head, protrude as modifications to puncture food and bring out the

fluids contained inside

Scrapers/GrazersAdapted to remove and consume the thin layer of algae and bacteria that grows tightly attached to solid substrates in shallow waters• Jaws of scrapers have sharp, angular edges

(function like using a putty knife or paint scraper)

(flathead mayflies, water pennies, snails)

Engulfer-Predators

Feed upon living animals, either by swallowing the entire body of small prey or by tearing large prey into pieces that are small enough to consume(common stoneflies and hellgrammites)

FFG Examples

Diet Characteristics

Predators

Dragonflies, damselflies, stoneflies

Other insects Toothy jaws, larger in size

Shredders

Stoneflies, beetles, caddisflies

CPOM, leaves, woody debris

Streamlined, flat

Grazers / Scrapers

Mayflies, caddisflies, true flies, beetles

Periphyton, diatoms

Scraping mandibles

Gathering Collectors

Mayflies, worms, midges, crayfish

FPOM, settled particles, bacteria

Filtering hairs, hemoglobin

Filtering Collectors

Black flies, net-spinning caddisflies, mayflies

FPOM, phytoplankton, floating particles

Some build cases (caddisflies)

Autochthonous vs. Allochthonous Inputs

Autochthonous – biomass produced within the system (in stream)

- algae, periphyton, macrophytes

Allochthonous – biomass produced outside the system (riparian and upland)

- tree and shrub leaves and needles

Light is a primary determinant of whether the food base for a given community is live green plants

growing within the aquatic environment or decaying plant material that originated in the terrestrial

environment

Functional Feeding Groups: The River Continuum(Vannote et al., 1980)

CPOM

FPOM

FPOM

STREAM ORDER

Relative Channel Width

HEADWATERS:• Shredders abundant• Coarse POM

MID-REACHES:• Grazers abundant• Higher 1° production

LARGE RIVERS:• Collectors abundant• Fine-Ultra fine POM

Life HistoryReproduction, growth, and development of an organism

Hermaphroditic organisms – contain both male and female reproductive organs (flatworms, aquatic earthworms, leeches, snails)Oviparous – females lay their eggs outside of their bodyOvoviviparous – females retain their eggs and allow them to hatch within their body and release free-living offspring

Growth is relatively simple in flatworms, aquatic earthworms and leeches because they are not restricted by any type of external protective structures

Exoskeleton of arthropods does not grow once it has been produced, so growth of the organism is restricted. As a result, arthropods must shed their skin (molt) in order to increase in size (3-45 times).

Mollusks are enclosed in non-living protective shells produced by the organism; shells are made of protein and calcium carbonate; made larger by adding material, like a tree growth ring

Insect Life Cycles Metamorphosis -

biological process involving a conspicuous and relatively abrupt change in the insect's body structure through cell growth and differentiation.

Complete metamorphosis is egg > larva (nymph) > pupa > adult

Incomplete metamorphosis

Insect Life Cycles Many (but not all) of the aquatic macroinvertebrates

are in the larval or nymphal stage while in a stream, and will eventually leave the water when they are adults that can fly.

Adult insects often have very short life spans, maybe only 24 hours or a few days. These insects may not live very long once removed from their stream habitat.

Voltinism Many invertebrates can pass through only a single

generation each year (or less), while others are capable of 2 or more generations

Univoltine – one brood or generation per year (most mayflies, caddisflies)

Bivoltine - two broods or generations per year (baetid mayflies)

Multivoltine - more than two broods or generations per year (some mayflies like Tricorythodes)

Semivoltine - generation time is more than one year (many stoneflies, dragonflies)

Stress Tolerance

Anthropogenicpollution, removal of water by irrigation, dams, deforestation, removal of riparian vegetation

Freshwater invertebrates vary in their ability to cope with environmental stress

Biomonitoring takes advantage of this situation by identifying whether an aquatic

environment is inhabited predominantly by stress tolerant or stress intolerant organisms

Natural volcanoes, forest

fires, floods, landslides

Classification of Macroinvertebrates used in Biomonitoring

Kingdom: Animalia

Phylum: Arthropoda (Arthropods) Annelida (Segmented Worms) Mollusca (Mollusks)

Group 1 Taxa

Pollution Sensitive Organisms Found In Good Quality Water

StonefliesMayfliesWater Pennies

DobsonfliesRiffle

BeetlesMussels

Stonefly Water Penny Beetle Mayfly Dobsonfly

Alderfly Mussel Snipe Fly Riffle Beetle

Macroinvertebrates as Indicators

Pollution Sensitive (“Clean Water”) Benthos

CaddisfliesDamselflies

DragonfliesBlackflies

CranefliesWater

Boatman

Backswimmers

Crayfish

Amphipods

Group 2 Taxa

Can Exist Under a Wide Range of Water Quality Conditions

Generally of Moderate Quality Water

Macroinvertebrates as Indicators

Blackfly Caddisfly Isopod Cranefly

Damselfly Dragonfly Crayfish Amphipod

Somewhat Pollution Tolerant Benthos

Midgeflies/ChironomidsWorms

LeechesPouch Snails

Group 3 Taxa

Can Exist Under a Wide Range of Water Quality Conditions, Generally are Highly

Tolerant of Poor Quality Water

Macroinvertebrates as Indicators

Pouch Snail Midgefly Worm Leech

Pollution Tolerant (“Polluted Water”) Benthos

The Tolerance Index0 - 10

most pollution sensitivee.g. Stoneflies

0 10

most pollution tolerant e.g. Midges & Leeches

require high DO, clear water, rocky cobble substrate

contain hemoglobin, tolerate lower DO, prefer soft substrate, less sensitive to toxins

HBI_MN Tolerance Values from Joel Chirhart

Ophiogomphus0

Lepidostoma0.12

Ephemerella0.26

Glossosoma1.14

Acroneuria2.40

Hesperophylax2.67

Perlodidae2.68

Baetidae7.18

Hyalella7.30

Hydropsychidae7.55

Hexatoma8.07

Stenelmis8.30

Caenis8.79

Orconectes9.41

Physa10

EPT Tolerance Values Family (Species range)

Leptophlebiidae2 (1-6)

Heptageniidae4 (0-7)

Ephemerellidae1 (0-2)

Baetiscidae3

Caenidae7 (3-7)

Isonychiidae2 (2-2)

Capniidae1 (1-3)

Leuctridae0 (0-0)

Taeniopterygidae2 (2-3)

Perlidae1 (0-4)

Rhyacophilidae

Brachycentridae

Limnephilidae

Hydropsychidae

0 (0-1)

1 (0-2)

4 (0-4)

4 (0-6)

Gomphidae1 (1-5)

Calopterygidae5 (5-6)

Aeshnidae3 (2-6)

Corydalidae0 (4)

Elmidae4 (2-6)

Psephenidae4 (4-5)

Tipulidae3 (2-7)

ChironomidaeTanypodinae (4-10)Podonominae (1-8)

Simulidae 6 (1-7)From: Benthic Macroinvertebrates in Freshwaters-

Taxa Tolerance Values, Metric and Protocols (Mandaville 2002)

Other taxa tolerance values, Family (species)

Biological Integrity “…the capability of supporting and maintaining a balanced, integrated, adaptive community of organisms having a composition, diversity and functional organization comparable to that of natural habitats of the region”

(Karr and Dudley 1981)

J.R. Karr First developed biotic index for fish

Became multi-metric index

IBIs are now used world-wide for many different taxa

Must be regionally calibrated with reference sites

The Index of Biotic Integrity (IBI) is useful because…

It is an ensemble of biological information It objectively defines benchmark

conditions It can assess change due to human causes It uses standardized methods It scores sites numerically, describes in

narrative form It defines multiple condition classes It has a strong theoretical basis It does not require fine resolution of taxa

Great candidates for biological monitoring…

Benthic Macroinvertebrates

Heptageniidae sp. (Mayfly larva)

Hydropsyche sp. (Caddisfly larva)

Perlodidae sp. (Stonefly larva)

Macroinvertebrates as Indicators Limited migration patterns – good indicators of

localized conditions and site-specific impacts Integrate effects of human impacts** Easy to sample and identify Broad range of habitat requirements

and sensitivities to pollution

Integrate effects of human impacts

EPA Recommendations

Build a comprehensive bioassessment data base

Test and validate metrics, or indices, to ensure they are reliable indicators of human disturbance and are able to discern between changes due to natural variability and human activity

Adopt numeric biocriteria for specific waterbody types sequentially into water quality standards as EPA publishes technical guidance for those waters

For each community characteristic (metric)

1) Does metric respond to stream impairment? Significant difference in metric between

reference and impaired sites?

2) How many metrics “work”? 3) Determine scoring for each metric

(continuous or categorical, 0-10?) 4) Combine scores for each metric: total score 5) Determine impairment threshold (standard)

Benthic Index of Biotic Integrity(B-IBI)

Index based on macroinvertebrate samples that integrates several metrics to produce an overall “health score” for a given water bodyResult: dose-response curves to human impact

Human Impact

IBI S

core

e.g. Taxa richness, relative abundance of certain taxa, feeding groups

e.g. Pollution, habitat degradation, flow alteration

Generalized Plot of B-IBI Scores vs. Human Impact

SE MN River/Stream Macroinvertebrate Assessments

Invertebrate Class 2 – Prairie Forest Rivers Watershed > 500 mi2 (Cannon, Root, Zumbro)

Invertebrate Class 5 – Southern Streams (Riffle/Run Habitats) Watershed < 500 mi2 (Root, Zumbro)

Invertebrate Class 6 – Southern Forest Streams (Glide/Pool Habitats) Watershed < 500 mi2 (Money, Root, Rush)

Invertebrate Class 9 – Southern Coldwater Streams Size? (Beaver, Pine, Trout, Whitewater, S.Br/S.F. Root)

Macroinvertebrate IBI Metric Categories

Composition (3 metrics)Habitat (2 metrics)Trophic (1 metric)

Tolerance (6 metrics)Richness (8 metrics)

Class 5 – Southern Streams (Run/Riffle Habitats)Biocriteria Threshold 35.9 (23.3 – 48.5)Metric Categor

yResponse

Description

ClimberCh Habitat Decrease Taxa richness of climbers

ClingerChTxPct

Habitat Decrease Relative % of taxa adapted to cling to substrate in swift flowing water

DomFiveChPct

Composition

Increase Realtive abundance (%) of dominant 5 taxa in subsample (Chir genera separate)

HBI_MN Tolerance Increase Average tolerance value of individuals in sample (Chirhart)

InsectTxPct Composition

Decrease Relative % of insect taxa

Odonata Richness Decrease Taxa richness of Odonata

Plecoptera Richness Decrease Taxa richness of Plecoptera

PredatorCh Richness Decrease Taxa richness of predators

Tolerant2ChTxPct

Tolerance Increase Relative % of taxa with tolerance values = or > 6, using MN TVs

Trichoptera Richness Decrease Taxa richness of Trichoptera