docStream Ecology - Teton Science Schools
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Stream Ecology - Teton Science Schools
Stream Ecology Freshwater Ecology substrate temperature light Physical current pH photosynthesis macrophytes Biological macroinvertebrates Chemical DO Turbidity fish Conductivity Macroinvertebrates “Macro” “Invertebrate” Large enough to be seen with the naked eye Lacking an internal skeleton of cartilage and bones Invertebrates account for 70% of all known species of living organisms (microbes, plants, and animals If we consider just animals, invertebrates account for 96% of known species 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 • Known as BIOMONITORING Macroinvertebrate Biology Habitat Movement Feeding Breathing Life History Stress Tolerance Habitat The place where an organism lives Running waters – lotic – seeps, springs, brooks, branches, creeks, streams, rivers Standing waters – lentic – bogs, marshes, swamps, ponds, lakes erosional (riffles, wave action) or depositional areas (point bars, pools) Mineral bedrock, boulders, cobbles, pebble, gravel, sand, silt, clay Organic live plants, detritus Movement Locomotion, habits, or mode of existence 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 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 Chew on intact or large pieces of plant material • have basic mouthparts, without any special modifications • basic mouthparts include two jaw like structures (mandibles) for cutting and grinding and often an upper lip (labrum) and a lower lip (labium) to help keep food in their mouths • Material is usually >1 mm, referred to as Coarse Particulate Organic Matter (CPOM) 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 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 • position themselves on the bottom and eat the detritus from the top of the sediment (non-biting midges) • burrow through the bottom and unselectively swallow the sediment and fine detritus as they go (aquatic earthworms) • finger-like projections from some of the mouthparts (palps) help them gather the fine particles of food Collector-filterers- use special straining mechanisms to feed on fine detritus that is suspended in the water • spin nets from silk (netspinner caddisflies) • have hairs on their heads (black flies) • appendages create water current for their feeding (mussels) Piercers mouthparts, or sometimes their entire head, protrude as modifications to puncture food and bring out the fluids contained inside mouthparts are modified into one or two hard, sharp, hollow tubes that they use to stab into their prey (water scorpions) 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 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) • After algae has been removed, the material is swept into the mouth by finger like projections from other mouthparts (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 • Typically have large jaws with pointed ends and sharp, tooth like projections for attacking and devouring their prey e.g. (common stoneflies and hellgrammites) Autochthonous vs. Allochthonous Inputs Autochthonous – the relative amount of biomass produced within the system (in stream) algae, periphyton, macrophytes Allochthonous – the relative amount of 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 River Continuum Concept River Continuum Concept Breathing Closed Breathing System Open Breathing System depend upon oxygen dissolved in the water for their breathing obtain oxygen directly from the atmosphere Oxygen enters the organisms by simple diffusion either through their general body surface or through gills that are specialized for this purpose, or both All some attach a quantity of air to their body, called an air store, and take it underwater to breathe from (either in a bubble or in a thin layer) Some have behavioral mechanisms, such as wriggling the body, to increase the rate of oxygen diffusion Others breathe by pushing either spiracles or some type of extension on the end of their body to the surface to reach the atmosphere (breathing tubes or siphons) Life History Reproduction, growth and development of an organism Hermaphroditic organisms – contain both male and female reproductive organs (flatworms, aquatic earthworms, leeches, snails and mussels) 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 Exoskeletons 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 covers produced by the organism, called shells; shells are made of protein and calcium carbonate; made larger by adding material, like a tree growth ring Complete Metamorphosis Incomplete Metamorphosis Stress Tolerance Natural volcanoes, forest fires, floods, landslides 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 Classification 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 Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Plecoptera “plekein” – to braid (wings of adult are folded to fit under front wings) Families: Perlidae “ptera” – tail Perlodidae Leuctridae Plecoptera: Stoneflies • 3 pairs of segmented legs on thorax • 2 tarsal claws • 2 stick-like tails • gills on thorax (often where leg joins thorax) • long antennae • double set of wings • wing pads are often visible • most are crawlers • shredder-detritivores or engulfer-predators Incomplete Metamorphosis Adults: long, thin antennae that project from the head Both pairs of wings are membranous and have many veins Wings fold, when not is use, so that they lie flat over the abdomen Ephemeroptera: Mayflies “ephemeros” – lasts a day “Ptera” - wings Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Ephemeroptera Families: Baetidae Heptageniidae Ephemeridae • Usually has 3 tails, although some with 2 Incomplete Metamorphosis • single tarsal claw • 3 pair of segmented legs on thorax Adults have • gills occur on abdomen (flat plates or filaments) triangular shaped • short antennae wings that are held straight up when • have a single set of wingpads body is at rest • scraper/grazer or collector-gatherers Coleoptera: Beetles Water Penny Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Coleoptera Family: Psephenidae “koleon” – sheath hardened front wings provide protective cover “ptera” – wing for hind wings and abdomen Complete Metamorphosis • thin, flat, flexible plates to help mold body to rock shape • single hooks at the end of legs • jaws have thin sharp edge to scrape algae • dense fringe of fine hairs to increase grip on rocks • gills occur on underside of abdomen • lotic-erosional • clingers • scrapers Megaloptera: Dobsonflies and Fishflies (Hellgramites) “megal” – large or of giant size “ptera” – tail Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Megaloptera Family: Corydalidae Complete Metamorphosis • 6 legs • large mandibles, projecting toothed jaws • large elongate bodies • head and thorax have thick, hardened skin, abdomen thin and soft • 8 pairs of lateral filaments from abdomen segments • gill tufts • no wing pads occur on thorax • engulfer-predators • primarily lotic-erosional • primarily crawlers, some burrowers, sprawlers Adults: cylindrical bodies soft abdomen Wings are large, elongate, membranous with many veins wings held slanted and roof like over the abdomen Coleoptera: Beetles Riffle Beetle Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Coleoptera Family: Elmidae “koleon” – sheath hardened front wings provide protective cover “ptera” – wing for hind wings and abdomen Complete Metamorphosis • segmented, hardened, worm-like body • gills protrude from end of abdomen • primarily lotic-erosional, lentic-littoral • scrapers, collector-gatherers • primarily clingers, also climbers Mollusca: Mussels “mollu” – hard or brittle external coat “bi” – two “valva” – hinged and movable pieces “volvere” – to roll or wrap • mussels and clams are mollusks that have two shells • often the largest invertebrates present in freshwater environments • live throughout lotic and lentic habitats • collector-filterers, have tubular siphons that create a one way current, cilia and mucous coating on gill filaments filter suspended particles of food • burrowers • have parasitic larval stage Kingdom: Animalia Phylum: Mollusca Class: Bivalvia Group 2 Taxa Can Exist Under a Wide Range of Water Quality Conditions Generally of Moderate Quality Water Caddisflies Damselflies Dragonflies Blackflies Craneflies Water Boatman Backswimmers Crayfish Amphipods Trichoptera: Caddisflies “trich” – hair “ptera” – tail • 6 segmented legs • worm-like bodies • no easily visible antennae • thick, hardened skin on head • either live in a fixed retreat or makes a portable case • shredder-detritivores, shredder-herbivores, collector-gatherers, collector-filterers, and scrapers Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Trichoptera Family: Hydropsychidae Family: Limnephilidae Family: Helicopsychidae Complete Metamorphosis Adults have long wings folded back Odonata: Dragonflies and Damselflies Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Odonata Families: Aeshnidae “odon” – tooth, refers to mouthparts of the adults Gomphidae Libellulidae • Wing pads are present on the thorax Families: Calopterygidae • Three pairs of segmented legs extend from the thorax Coenagrionidae • Two claws occur on the end of segmented legs Lestidae • No gills are found on the sides of the abdomen, but some have three, elongate gills Incomplete Metamorphosis • Bodies are either long and stout or oval and somewhat flattened • Head is narrower than the thorax and abdomen • No gills are found on the end of the abdomen • Three short, stiff, pointed structures occur on the end of the abdomen, forming a pyramid-shaped valve for the opening on the end of the abdomen • body is elongate and slender • head is wider than the thorax and abdomen • three flat, elongate gills project from the rear of the abdomen Hemiptera: True Bugs Water Striders Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Hemiptera Family: Gerridae “heteros” – different Half wing near body is leathery, half is membranous “ptera” - wing • 3 pairs of segmented legs on thorax • legs are skinny and long to help distribute body weight • 2 claws on segmented legs • only middle and hind legs touch water; front legs are held up • piercer-predators • skaters • lentic-limnetic or lotic-depositional Incomplete Metamorphosis Hemiptera: True Bugs Water Boatman Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Hemiptera Family: Corixidae “heteros” – different Half wing near body is leathery, half is membranous “ptera” - wing Incomplete Metamorphosis • well developed, prominent eyes • modified beak (blunt, triangle shaped non-segmented mouth) • swims upright (backswimmers swim on back) • have short front legs, much shorter than other pairs of legs • two long claws on mid pair of legs • swimming hairs • 2 pair of long hind legs with swimming • dark colored back, light colored stomach • hind legs are oarlike with swimming hairs • front legs with stiff setae (hairs) to be used like a rake • surface for air; thin film of air on underside (plastron) • collector-gatherers • lentic-littoral and lotic-depositional habitats Hemiptera: True Bugs Backswimmers Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Hemiptera Family: Notonectidae “heteros” – different Half wing near body is leathery, half is membranous “ptera” - wing Incomplete Metamorphosis • oval shaped body, dark colored stomach • swims on back • has short front legs • hind pair of legs are oarlike with swimming hairs • has narrow, segmented beak (mouth) • uses hind legs as oars • usually red eyes, well-developed and prominent • dark colored stomach, light colored back • lentic-littoral and lotic-depositional habitats • swimmers • piercer-predators • hold stored air in two troughs with fringes of hair on the bottom of abdomen Diptera: True Flies Blackfly “di” – two True flies have two wings, other insects have four “ptera” - wing Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Diptera Family: Simulidae Complete Metamorphosis • worm-like with one swollen end (bowling pin) • usually dark in color • usually live in colonies • have well developed, hardened head • fan-like mouth with brushes used for eating • proleg under head • have disc at rear end with many small hooks to attach to rocks • lotic-erosional • clingers-use silk to stick to substrate • collector-filterers Diptera: True Flies Crane Flies “di” – two True flies have two wings, other insects have four “ptera” - wing • fleshy, plump, segmented, worm-like body • no legs, no wings • usually brown, white or green in color • head is retractable • two spiracles on posterior used for breathing • burrowers, sprawlers • shredder-detritivores, collector-gatherers • lentic-littoral; lotic-erosional, lotic-depositional Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Diptera Family: Tipulidae Complete Metamorphosis Crustacea: Crustaceans Decapoda (Crayfish) “crusta” – hard or brittle external coat “deka” – ten “poda” – foot Kingdom: Animalia Phylum: Arthropoda Subphylum: Crustacea Class: Malacostraca Order: Decapoda Family: Astacidae Crayfish have five pairs of walking legs Incomplete Metamorphosis • one pair of antennae much longer than others • 5 pairs of walking legs • 2-3 pair of walking legs have hinged claw • other legs have pointed tip • 2 large, compound eyes • live in a variety of habitats • are mostly nocturnal • omnivores Crustacea: Crustaceans Amphipods (Scuds/Sideswimmer) Kingdom: Animalia Phylum: Arthropoda Subphylum: Crustacea Class: Malacostraca Order: Amphipoda Incomplete Metamorphosis “crusta” – hard or brittle external coat “amphi” – of both kinds “poda” – foot Two kinds of appendages on bottom of body • 7 pair of legs • 2 pair of antennae • head fused to thorax • laterally flattened • white or clear body with many segments • swims sideways and rests in a curved position • occur in many habitats • omnivores, many functional feeding groups Group 3 Taxa Can Exist Under a Wide Range of Water Quality Conditions, Generally are Highly Tolerant of Poor Quality Water Midgeflies/Chironomids Worms Leeches Pouch Snails Diptera: True Flies Midge/Chironomid “di” – two True flies have two wings, other insects have four “ptera” - wing • small, slender, slightly curved body • hardened head capsule (often yellow) • sometimes has a brush like structure at rear • occur in all types of habitats • primarily burrowers • primarily collector-gatherers Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Diptera Family: Chironomidae Complete Metamorphosis Kingdom: Animalia Phylum: Annelida Class: Oligochaeta “olig” – long “chaite” - hair Kingdom: Animalia Phylum: Annelida Class: Hirudinia Order: Rhynenobdella Worms and Leeches Incomplete Metamorphosis • body is soft, moderately muscular, elongate and cylindrical • body consists of round, ring-like segments arranged in a row • each segment after the first has bundles of tiny hairs (chaetae) • no suckers or eyespots are present • lentic-littoral, lotic-depositional • burrowers, collector-gatherers Incomplete Metamorphosis • flat, segmented body • head section usually skinnier than rear • body shape can change with movement • ventral side is usually paler in color • ventral suckers on both ends • sometimes attach to and feed off other organisms Mollusca: Clams, Mussels, Snails Kingdom: Animalia Phylum: Mollusca Class: Gastropoda “mollu” – hard or brittle external coat “gaster” - stomach “pod” - foot digestive system begins in muscular foot projecting from shell • snails are freshwater mollusks with one shell • divided into two major groups, based on breathing • some breathe oxygen dissolved in water (gilled snails) • others obtain oxygen from air by structure that works like a lung (lunged snails) • lentic-littoral, lotic-depositional, lotic-erosional • scrapers Pollution Indices EPT - # of EPT taxa found in stream (Ephemeroptera, Plecoptera, Trichoptera) mayflies, stoneflies, caddisflies % of Aquatic Worms (% of Midges) numbers of individuals found that are midges Pollution Sensitivity Index – Assigns Scores to Each Type of Macroinvertebrate - sum ten indices to get a composite score
