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Biomonitoring. the study of biological organisms and their responses to environmental conditions; can be fish, algae or insect communities. Benthic macroinvertebrates. Benthic = Live on or in bottom substrate Macro = Large enough to be seen with unaided eye
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Biomonitoring the study of biological organisms and their responses to environmental conditions; can be fish, algae or insect communities
Benthic macroinvertebrates • Benthic = Live on or in bottom substrate • Macro = Large enough to be seen with unaided eye • Invertebrate = Animal without a backbone
Why study macroinvertebrates? • Affected by the physical, chemical and biological conditions of stream • Can’t escape pollution - show the effects of short and long-term pollution events • Can show the cumulative impacts of pollution • May show the impacts of habitat loss
Why study macroinvertebrates? • Critical part of the stream’s food web • Relatively easy to sample and identify (easier than algae) • Have greater diversity in stream than fish - sport fishing, stocking of fish and exotic species have altered fish community
Key identification features • Overall body shape (NOT SIZE) • Case made of sticks, leaves, stone • Legs • Presence and location of gills • Presence and location of cerci (“tails”) • Head capsule, unusual appendages • Movement (crawl; swim side-to-side, up-down)
Legs and prolegs Prolegs on midge Caddis removed from case
Gills Mayfly (Speckle-Winged Quill, Callibaetis)
Cerci (tails) Baetis has center tail that is ½ length of outer tails
Stoneflies (Plecoptera) Sensitive Nymphs: • Two distinct "tails" called cerci, which are actually sensory feelers • Usual movement = crawl; swim side-side • Insect nymphs with three pair of jointed legs, each with paired claws. • Two pair of wing pads (developing wings) present on thorax. • No gills along abdomen • Length up to 3 inches
Stoneflies (Plecoptera) Sensitive • Feeding types: • Predator • Shredder • Omnivore • Adults: • resemble nymphs, but possess a long pair of wings folded down the length of the body. • Eaten by a variety of fish species
Mayflies (Ephemeroptera) Sensitive Nymphs: • Three tails, occasionally two • Gills usually visible on abdomen • Typical movement = crawl, swim (up-down) • Small - Total length < 1 inch
Mayfly nymph (Pale Evening Dun) Head is widest part of body
Mayfly nymph (Small Yellow May) Nymph with only two tails Head is widest part of body
Mayflies (Ephemeroptera) Sensitive • Feeding Types: • Collector-Gatherers • Scrapers • Adults: • Resemble nymphs with two pair of long, lacy wings folded upright • Adults usually have only two tails (cerci) • Food for fish and predatory macroinvertebrates
Caddisflies (Tricoptera) Sensitive Larvae: • Soft “worm-like”bodies • Head contains a hard covering • Larvae are known for their construction of hollow cases that they either carry with them or attach to rocks • built from twigs or bark, small stones, or rolled leaves • used for protection and pupation • Anal hooks usually present • Large - Length up to 2 inches
“Free-living” CaddisflySpotted sedge Branched gills on abdomen
Caddisflies (Tricoptera) Sensitive • Feeding Types: • Predators • Grazers • Collector-Gatherers • Adults: • “Moth-like”; usually nocturnal • Wings fold into “tent” on back • Eaten by fish and by some macroinvert predators • Collector-Filterers • Scrapers • Shredders
Water Pennies (Coleoptera)Sensitive • Circular-shaped • Attach firmly to rocks • Sensitive – need high oxygen and fast flowing water
MegalopteraSensitive • Dobsonfly/ hellgrammites (Corydalidae) • Large mandibles • 2 short “tails” • Predator • Alderfly (Sialidae) • Long, single “tail” • Predator
OdonataWide range • Damselfly • 3 fan-shaped caudal gills • Dragonfly • Robust body • Well-developed “jaws”
Crayfish (Decapoda)Wide Range • 4 pairs of walking legs • Large pair of pinchers • Up to 6 inches
Scuds (Amphipoda)Wide Range • “Shrimp-like” • 14 feet • Prefer muddy substrate with rooted vegetation
Cranefly (Diptera)Wide Range • Worm-like • Head capsule, usually retracted into “accordion-like” body • Shredders
Midge Larvae (Diptera)Tolerant • Pear-shaped body, with swollen base where they attach • Filter feeders
Snails (Gastropoda)Tolerant • Cylindrical shell • May be right or left handed
OthersTolerant • Worms (Oligochaeta) • Segmented bodies • Leeches (Hirundinea) • Suckers at both ends
Green Rock Worm (Tricoptera) • No case • Predator • Found in riffles Only first thoracic segment has hard shell Pair of anal hooks
Riffle Beetle (Coleoptera) • Hard shelled, tube-shaped larvae • Found in riffles • No tails or anal hooks Gills concealed in chamber at rear of abdomen
Midge Larvae (Diptera) • Head capsule • No jointed legs • Variety of colors • Prolegs on 1st thoracic and last abdominal segments Prolegs Prolegs
Data Analysis • Data collection is key • Level of ID determines level of analysis • Score (5) vs. interpretation (“POOR”) • Use the same data analysis tool for comparing data • Local-scale tool most accurate • Requires time • High quality “reference” sites
Pollution Tolerance Index • National-level tool • ID to Order • 3 groups • Pollution Sensitive (3 pts) • Wide Range (2 pts) • Pollution Tolerant (1 pt) • Data limited since # organisms not considered
Example PTI calculation PTI = (1x3)+(1x2)+(3x1) = 8 (POOR)
Hilsenhof Biotic Index (HBI) • Considers organic pollution • ID to Family or lower • 10-point scale where: • 0 = most sensitive • 10 = most tolerant • # organisms is considered • Sometimes included as 1 metric in a multi-metric analysis, such as IBI
Hilsenhof Biotic Index (HBI) HBI = (Taxa count) (HBI score) (Total count) Rating:
Example HBI calculation HBI = (11x8)+(57x4)+(3x4)+(14x7)+(5x8) 90 HBI = 5.18 (POOR/Enriched)
Biometrics “Biometric” - a measure of some characteristic of the biological community • Taxa Richness and Composition • EPT • Tolerance and Intolerance • HBI • Feeding Ecology • % or abundance of functional feeding groups • Population Attributes • dominance
Family-level metrics • Taxa Richness (# diff taxa identified) • Mayfly Taxa • Stonefly Taxa • Caddisfly Taxa • % Diptera • HBI
Multi-metric indices • Include several (usually 5-10) metrics • Combined, they measure various aspects of stream health • Examples: • Index of Biological Integrity (IBI) • State of Oregon Multi-metric Index