Tecnico En Salud Zcomunitaria

8/22/2012

Stream Ecology

Freshwater Ecology
substrate temperature light current pH

Physical

photosynthesis

macrophytes

Biological

Chemical

DO

macroinvertebrates

Turbidity fish Conductivity

Macroinvertebrates

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

“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

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 wateris healthy or unhealthy and may reveal the cause of the problem • Known as BIOMONITORING

Macroinvertebrate Biology
Habitat Movement Feeding Breathing Life History Stress Tolerance

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Habitat
The place where an organism lives
Running waters – lotic – seeps, springs, brooks, branches, creeks, streams, rivers Standing waters – lentic – bogs, marshes, swamps, ponds, lakesMovement
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 formoving through water Skaters – adapted to remain on the surface of water

erosional (riffles, wave action) or depositional areas (point bars, pools)

Mineral bedrock, boulders, cobbles, pebble, gravel, sand, silt, clay

Organic live plants, detritus

Feeding
Macroinvertebrates are described by how they eat, rather than what they eat

Shredders
Chew on intact or large pieces of plantmaterial
• 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 submergedin the water (northern casemaker caddisflies)

Functional Feeding Groups – categories of macroinvertebrates based on body structures and behavioral mechanisms that they use to acquire their food

Shredder-detritivores feed on detritus, or dead plant material in a state of decay (giant stoneflies)

Collectors
Acquire and ingest very small particles ( immature (larva) > Pupa > Adult  2)During pupal stage adult characteristics develop  3) Examples include; caddisflies and dipterans such as blackflies

Incomplete Metamorphosis
Holometabolous Hemimetabolous

Stress Tolerance
Natural volcanoes, forest fires, floods, landslides Anthropogenic pollution, removal of water by irrigation, dams, deforestation, removal of riparian vegetation

 Hemimetabolous

insects pass throughthree stages in their life cycle:  1) Egg > Immature (nymph) > Adult  2) Adults are terrestrial  3) Examples include; stoneflies, mayflies, and dragonflie

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...