Stream Ecology
and
Macroinvertebrate Biology
Background Information for
Developing your Research Project
Ecology
• Definition: The study of interactions between
individuals and individuals and their environment
• Simplified Food Chains:
– Plants  Herbivores  Predators
– Dead organic matter  Detritivores  Predators
• Much green material in temporal areas is not eaten by herbivores,
but is delivered to the detrital pool
• Detritus  Dead, decaying, particulate organic matter
Sun
Leaves
Microbes
Algae
(fungi, bacteria)
Smaller leaf particles
Shredders
(crane flies, some caddisflies and
stoneflies, sowbugs, and scuds)
Collectors/ Gatherers
(black flies, net-spinning
caddisflies, mayflies, midges)
Predators
(Dobson flies, dragonflies/ ”hellgrammites”)
Source: A. Berkowitz, posted by T. Meyers
Grazers/ Scrapers
(caddisflies, water pennies,
midges, and mayflies)
http://www.stroudcenter.org/lpn/LPNmanual/2_BackgroundInformation.pdf
Functional Feeding Groups of
Macroinvertebrates
• Shredders
– Consume coarse organic matter, such as leaves (Sowbugs)
• Collectors
– Consume fine pieces of organic matter, such as leaf fragments
or other material on stream bottom
– Filtering Collectors (Clams)
– Gathering Collectors (Caddisfly larvae)
• Scrapers
– Feed on attached periphyton located on submerged
underwater surfaces (Example: Snails)
• Predators
– Feed on other invertebrates (Example: Dragonflies)
Food processing…
of this detritus is a major ecosystem function
• Soil formation
• Supports predators
– (some predators consumed by humans)
• Processed in streams
– If it accumulated, would create anoxic conditions
• Influence of processing rates:
– Quality of detritus (P, N, polyphenols, lignins, etc)
– Fungi and bacteria colonization
– Invertebrate feeding
Ecological Interactions
• Microbes and invertebrates process and get
energy from detritus
– Microbes often overlooked on many levels
• Different species process materials at different
rates
– If a species is lost, the entire ecosystem function
will change
– Species are being lost at an alarming rate
Adaptations
Variations of anatomy/structure allow for
tolerance, feeding capacities, and competition
Trichoptera (Caddisflies)
((Scuds) (Scuds)
Amphipoda (Scuds)
Importance
• Impacts on Humans
– Aug. 17, 1988, an 85 foot section of Rt. 675 Bridge collapsed over the
Pokomoke (Eastern Shore)
– Reduction in cross section area of piles 18-35%
• Due to: Bacteria and fungal decay, Caddisfly decay, water currents
– In 1977, MDE estimated Caddisflies occupied 30-100% of the underwater pile
surfaces
– From 1976-1986, Caddisflies per 1.5 sq feet in the area averaged 543.5
• (High 1977=1837; Low 1986=50)
– Since 1977, 3 underwater inspections, pile measurements were inconsistent
– If use “Chemically Treated Wood,” less fungal and bacterial growth, therefore,
less caddisflies
Trichoptera Biology
• Taxonomy:
–
–
–
–
–
Phylum Arthropoda
Class Insecta
Order Trichoptera
Family Lepidostomatidae
Genus Lepidostoma
• Larvae feed on detritus (shredders)
• Protective cases
• You will identify these to Order at the
stream, and to Family in the lab
Amphipoda Biology
• Scuds; Detritivores (Shredders)
• Taxonomy:
– Phyllum Arthopoda
– Class Malacostraca
– Superorder Peracarida
– Order Amphipoda
– Family Gammaridae
Trichoperta Life Cycles
Complete
Metamorphosis
Amphipoda Life Cycle
Incomplete Metamorphosis
Tolerance/Sensitivity of Macroinvertebrates
• Macroinvertebrates can also be categorized by their
level of tolerance or sensitivity to stream conditions
–
–
–
–
Dissolved oxygen
Nutrients
Pollutants
Chemical quality
• Some species can live in “lower” quality water, and are
said to be:
– More tolerant
– Less sensitive
Shredders Roles
• Ecological/Trophic
– Leaf litter breakdown
• CPOMFPOM
– Course Particulate Organic Matter
– Fine Particulate Organic Matter
• Human Impact
• Predators (Trout, etc)
• Bio-indicator
– 0 - 3.75 = No Impairment Evident
– 3.75 - 6.50 = Moderate Impairment
– >6.5 = Severe Impairment
Selected Major
Taxa
Mayflies
Stoneflies
Caddisflies
TV
2
1
3
Density
16
14
142
TxD
32
14
426
6
2
12
Midges - Red
Beetles
Order/Family
Ephemeroptera
Plecoptera
Tricoptera
Chironomidae,
Diptera
Chironomidae,
Diptera
Coleoptera
8
4
0
6
0
24
Aquatic Worms
Oligochaeta
8
2
16
Crane Flies
Tipulidae, Diptera
3
3
9
Black Flies
Simuliidae, Diptera
6
5
30
Snipeflies
Anthericidae, Diptera
2
3
6
Other Flies
Dragon/Damselfli
es
Diptera
6
0
0
Odonnata
5
0
0
Hellgramites
Alderflies
Scuds
Sowbugs
Crayfish
Megaloptera
Megaloptera
Amphipoda
Isopoda
Decapoda
0
4
8
8
6
0
0
8
2
0
0
0
64
16
0
Snails/Limpets
Gastropoda
7
1
7
Clams/Mussels
Leeches
Pelecypoda
Hirudinea
7
10
11
0
77
0
Midges - White
Density Total
T x D Total
Biotic Index (T x D) ÷
Density
3.41
215
733
Source: A. Berkowitz, posted by T. Meyers
E=Ephemeroptera (Mayflies)
P=Plecoptera (Stoneflies)
T=Trichoptera (Caddisflies)
Stream Water Chemistry
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•
•
•
•
•
pH
Temperature
Nitrates
Phosphates
Chloride
Dissolved Oxygen
What Is a Watershed?
A watershed is the area of land that drains
to a particular point along a stream
Center for Watershed Protection
What is a Watershed?
Definition: the area of land that drains to a
particular point along a stream
Each stream has its own watershed
Topography is the key element affecting this area
of land
The boundary of a watershed is defined by the
highest elevations surrounding the stream
OK, now I know that
I live in a watershed …
what types of things
can affect the
health of my watershed?
High levels of paved surfaces,
or impervious cover, and land
use changes can have many
impacts on a watershed.
Center for Watershed Protection
Harmful Pollutants in Runoff
•
•
•
•
•
•
Bacteria
Nutrients
Pesticides
Oil and Grease
Turbid (muddy) water
Heavy Metals (zinc, lead, copper)
Impervious
Surfaces
Riparian Zone
• Definition: The interface between land and a stream
• Riparian vegetation is often planted as part of stream
restoration efforts because it can:
–
–
–
–
–
–
Remove nutrients from runoff (from fertilizers, etc)
Biofilter pollutants
Trap sediment (less turbid water, improve stream banks)
Improve wildlife habitat
Shade water, mitigating water temperature changes
Reduce soil erosion, reduce flood damage
What is the best way to evaluate
stream health?
• Water chemistry is more transient than biotic
index of macroinvertebrates due to:
– Point-source pollution
– Rain events
– Seasonal road salting
– Inconsistent littering/dumping
Physical Regions of a Stream
Riffle: Rapidly moving water,
turbulent
Pool: Deep, slowly
moving water
Run: Smooth flowing water, medium water speed
How do you think these different habitat types
will effect water chemistry and
macroinvertebrate populations?
Your Research Project
Objective is to utilize a learned understanding of
stream ecology and macroinvertebrate biology
to investigate the effects of habitat
preference, possibly due to available nutrients
and dissolved oxygen, on macroinvertebrate
species diversity and abundance in Hereford
High School’s stream
How can we do this??
Leaf Packs
Natural
Artificial