Biology & Ecology of SE MN Karst Region Streams Macroinvertebrate 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 BiologicalChemical 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 Macroinvertebrates Mayflies (Ephemeroptera) Baetidae EphemerellidaeHeptageniidae Isonychiidae (Adult)

Common Macroinvertebrates Stoneflies (Plecoptera) Perlidae Pteronarcydiae Perlodidae (Adult)

Common Macroinvertebrates BrachycentridaePhryganeidae 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

Habitat The 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) Organic live 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

Feeding Macroinvertebrates 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/Grazers Adapted 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 orby tearing large prey into pieces that are small enough to consume (common stoneflies and hellgrammites)

FFGExamplesDietCharacteristics Predators Dragonflies, damselflies, stoneflies Other insectsToothy 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 STREAM ORDERSTREAM 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 History Reproduction, 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 body Ovoviviparous – 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 Anthropogenic pollution, 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 Stoneflies Mayflies Water Pennies Dobsonflies Riffle Beetles Mussels

Stonefly Water Penny Beetle Mayfly Dobsonfly Alderfly Mussel Snipe Fly Riffle Beetle Macroinvertebrates as Indicators Pollution Sensitive (“Clean Water”) Benthos

Caddisflies Damselflies Dragonflies Blackflies Craneflies Water 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/Chironomids Worms Leeches Pouch 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 Index most pollution sensitive e.g. Stoneflies 010 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 Ophiogomphus 0 Lepidostoma 0.12 Ephemerella 0.26 Glossosoma 1.14 Acroneuria 2.40 Hesperophylax 2.67 Perlodidae 2.68 Baetidae 7.18 Hyalella 7.30 Hydropsychidae 7.55 Hexatoma 8.07 Stenelmis 8.30 Caenis 8.79 Orconectes 9.41 Physa 10

EPT Tolerance Values Family (Species range) Leptophlebiidae 2 (1-6) Heptageniidae 4 (0-7) Ephemerellidae 1 (0-2) Baetiscidae 3 Caenidae 7 (3-7) Isonychiidae 2 (2-2) Capniidae 1 (1-3) Leuctridae 0 (0-0) Taeniopterygidae 2 (2-3) Perlidae 1 (0-4) Rhyacophilidae Brachycentridae Limnephilidae Hydropsychidae 0 (0-1) 1 (0-2) 4 (0-4) 4 (0-6)

Gomphidae 1 (1-5) Calopterygidae 5 (5-6) Aeshnidae 3 (2-6) Corydalidae 0 (4) Elmidae 4 (2-6) Psephenidae 4 (4-5) Tipulidae 3 (2-7) Chironomidae Tanypodinae (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 is an ensemble of biological information It objectively defines benchmark conditions It objectively defines benchmark conditions It can assess change due to human causes It can assess change due to human causes It uses standardized methods It uses standardized methods It scores sites numerically, describes in narrative form It scores sites numerically, describes in narrative form It defines multiple condition classes It defines multiple condition classes It has a strong theoretical basis It has a strong theoretical basis It does not require fine resolution of taxa 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 body Result: dose-response curves to human impact Human Impact IBI Score 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 mi 2 (Cannon, Root, Zumbro)  Invertebrate Class 5 – Southern Streams (Riffle/Run Habitats)  Watershed < 500 mi 2 (Root, Zumbro)  Invertebrate Class 6 – Southern Forest Streams (Glide/Pool Habitats)  Watershed < 500 mi 2 (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) MetricCategoryResponseDescription ClimberCh Habitat Decrease Taxa richness of climbers ClingerChTx Pct Habitat Decrease Relative % of taxa adapted to cling to substrate in swift flowing water DomFiveCh Pct 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 Tolerant2Ch TxPct Tolerance Increase Relative % of taxa with tolerance values = or > 6, using MN TVs Trichoptera Richness Decrease Taxa richness of Trichoptera