Stream Ecology
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 1/45
Stream Ecology
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 2/45
F reshwater Ecology
Physical
Biological Chemical
light
currenttemperature
substrate
pH
DO
Turbidity
Conductivity
photosynthesis
macroinvertebrates
macrophytes
fish
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 3/45
M acroinvertebrates
³Macro´
³I
nvertebrate´
Large enough to be
seen with the naked
eye
Lacking an internal
skeleton of cartilageand 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
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 4/45
he Importance of M acroinvertebrates
Macroinvertebrates are anessential component of
freshwater ecosystems
They serve as food for other
organisms (fish, amphibiansand waterfowl)
Are essential to the breakdown
and cycling of organic matter
and nutrients
Macroinvertebrate diversity is
vital to a properly
functioning ecosystem
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 5/45
W hy Study M acroinvertebrates? 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 revealwhether a body of water is
healthy or unhealthy and may
reveal the cause of the problem
K nown as BIOMONITOR I NG
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 6/45
M acroinvertebrate Biology
Habitat
Movement
Feeding
Breathing
Life History
S
tress Tolerance
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 7/45
H abitat 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
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 8/45
M ovement
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 legsS prawlers ± 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
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 9/45
F eeding
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
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 10/45
Shredders
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)
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)
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 11/45
C ollectors
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)
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
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 12/45
P iercers
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
mouthparts are modified into one or two hard, sharp, hollow tubes that they use to
stab into their prey (water scorpions)
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 13/45
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 byfinger like projections from other
mouthparts
(flathead mayflies, water pennies, snails)
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 14/45
Engulfer- P redators
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 attackingand devouring their prey
e.g. (common stoneflies and hellgrammites)
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 15/45
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
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 16/45
River C ontinuum C oncept
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 17/45
River
C ontinuumC oncept
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 18/45
Breathing
Closed Breathing System
depend upon oxygen dissolved in the
water for their breathing
Oxygen enters the organisms bysimple diffusion either through their
general body surface or through gills
that are specialized for this purpose,
or both
Some have behavioral mechanisms,such as wriggling the body, to
increase the rate of oxygen diffusion
Open Breathing System
obtain oxygen directly from the
atmosphere
All some attach a quantity of air totheir body, called an air store, and take
it underwater to breathe from (either in
a bubble or in a thin layer)
Others breathe by pushing either
spiracles or some type of extension onthe end of their body to the surface to
reach the atmosphere (breathing tubes
or siphons)
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 19/45
Life H istoryReproduction, 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
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 20/45
C omplete M etamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 21/45
Incomplete M etamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 22/45
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 identifyingwhether an aquatic environment is inhabited predominantly by stress
tolerant or stress intolerant organisms
Natural
volcanoes, forest
fires, floods,
landslides
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 23/45
C lassification
K ingdom: Animalia
Phylum: Arthropoda (Arthropods)
Annelida (Segmented Worms)
Mollusca (Mollusks)
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 24/45
Group 1 Taxa
Pollution Sensitive Organisms Found In
Good Quality Water
StonefliesMayflies
Water Pennies
Dobsonflies
Riffle BeetlesMussels
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 25/45
P lecoptera: StonefliesK ingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Plecoptera
Families: Perlidae
Perlodidae
Leuctridae
³ plekein´ ± to braid (wings of adult are folded to fit under front wings)
³ ptera´ ± tail
3 pairs of segmented legs on thorax
2 tarsal claws
2stick-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
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 flatover the abdomen
Incomplete Metamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 26/45
Ephemeroptera: M ayfliesK ingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Ephemeroptera
Families: Baetidae
Heptageniidae
Ephemeridae
³ephemeros´ ± lasts a day
³Ptera´ - wings
Usually has 3 tails, although some with 2
single tarsal claw
3 pair of segmented legs on thorax
gills occur on abdomen (flat plates or filaments)
short antennae
have a single set of wingpads
scraper/grazer or collector-gatherers
Adults havetriangular shaped
wings that are held
straight up when
body is at rest
Incomplete Metamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 27/45
C oleoptera: Beetles
W
ater P
enny
K ingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Psephenidae
³koleon´ ± sheath
³ ptera´ ± wing
hardened front wings provide protective cover
for hind wings and abdomen
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
CompleteMetamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 28/45
M egaloptera: Dobsonflies
and F ishflies ( H ellgramites)
K ingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Megaloptera
Family: Corydalidae
³megal´ ± large or of giant size³ ptera´ ± tail
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 theabdomen
CompleteMetamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 29/45
C oleoptera: Beetles
Riffle Beetle
K ingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Elmidae
³koleon´ ± sheath
³ ptera´ ± wing
hardened front wings provide protective cover
for hind wings and abdomen
segmented, hardened, worm-like body
gills protrude from end of abdomen primarily lotic-erosional, lentic-littoral
scrapers, collector-gatherers
primarily clingers, also climbers
CompleteMetamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 30/45
M ollusca: M usselsK ingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
³ bi´ ± two
³valva´ ± hinged and movable pieces
³volvere´ ± to roll or wrap
³mollu´ ± hard or brittle external coat
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
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 31/45
CaddisfliesDamselflies
Dragonflies
Blackflies
CranefliesWater Boatman
Backswimmers
Crayfish
Amphipods
Group 2 Taxa
Can Exist Under a Wide Range of Water QualityConditions
Generally of Moderate Quality Water
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 32/45
Trichoptera: C addisfliesK ingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Trichoptera
Family: Hydropsychidae
Family: Limnephilidae
Family: Helicopsychidae
³trich´ ± hair
³ 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
Adults have long wings
folded back
CompleteMetamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 33/45
Odonata: Dragonflies and
Damselflies
K ingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Odonata
Families: Aeshnidae
Gomphidae
Libellulidae
Families: Calopterygidae
Coenagrionidae
Lestidae
³odon´ ± tooth, refers to mouthparts of the adults
body is elongate and slender
head is wider than the thorax and abdomen
three flat, elongate gills project from the rear of the abdomen
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 theabdomen, forming a pyramid-shaped valve for the opening
on the end of the abdomen
Wing pads are present on the thorax
Three pairs of segmented legs extend from the thorax
Two claws occur on the end of segmented legs
No gills are found on the sides of the abdomen, but
some have three, elongate gills Incomplete Metamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 34/45
H emiptera: True Bugs
W ater Striders
K ingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Family: Gerridae
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
³heteros´ ± different
³ ptera´ - wing Half wing near body is leathery, half is membranous
Incomplete Metamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 35/45
H emiptera: True Bugs
W ater Boatman
K ingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Family: Corixidae
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
³heteros´ ± different
³ ptera´ - wing Half wing near body is leathery, half is membranous
Incomplete Metamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 36/45
H emiptera: True Bugs
Backswimmers
K ingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Family: Notonectidae
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
³heteros´ ± different
³ ptera´ - wing Half wing near body is leathery, half is membranous
Incomplete Metamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 37/45
Diptera: True F lies
Blackfly
K ingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Simulidae
³di ± two
³ ptera´ - wingTrue flies have two wings, other insects have four
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
CompleteMetamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 38/45
Diptera: True F lies
C rane
F lies
K ingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Tipulidae
³di ± two
³ ptera´ - wingTrue flies have two wings, other insects have four
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
CompleteMetamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 39/45
C rustacea: C rustaceans
Decapoda ( C rayfish)
K ingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Family: Astacidae
³deka´ ± ten
³ poda´ ± foot
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
Crayfish have five pairs of walking legs
³crusta´ ± hard or brittle external coat
Incomplete Metamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 40/45
C rustacea: C rustaceans
Amphipods
(Scuds/Sideswimmer)
K ingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Amphipoda
³amphi´ ± of both kinds
³ poda´ ± foot
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
Two kinds of appendages on bottom of body
³crusta´ ± hard or brittle external coatIncomplete Metamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 41/45
Midgeflies/Chironomids
Worms
Leeches
Pouch Snails
Group 3 Taxa
Can Exist Under a Wide Range of Water QualityConditions, Generally are Highly Tolerant of Poor
Quality Water
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 42/45
Diptera: True F lies M idge/ C hironomid
K ingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Chironomidae
³di´ ± two
³ ptera´ - wingTrue flies have two wings, other insects have four
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
CompleteMetamorphosis
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 43/45
W orms and Leeches
K ingdom: Animalia
Phylum: Annelida
Class: Oligochaeta
K ingdom: Animalia
Phylum: Annelida
Class: Hirudinia
Order: Rhynenobdella
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
body is soft, moderately muscular,
elongate and cylindrical
body consists of round, ring-likesegments 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
³olig´ ± long
³chaite´ - hair
Incomplete MetamorphosisIncomplete Metamorphosis
i d A i li
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 44/45
M ollusca: C lams, M ussels,
Snails
K ingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
³mollu´ ± hard or brittle external coat
³gaster´ - stomach
³ pod´ - foot
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
digestive system begins in muscular foot
projecting from shell
8/8/2019 Freshwater Invertebrates
http://slidepdf.com/reader/full/freshwater-invertebrates 45/45
P ollution 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