Wetland Ecology and Management

 Definition (PA Code, Chapter 93): ◦ Spend a “living portion of their life cycle” in an aquatic environment ◦ Can be seen without the aid of a microscope ◦ Animals without a backbone  Examples: crayfish, snails, insect larvae

 Like plants, macroinvertebrates can serve as indicators of water quality.  Sensitive to a variety of chemical and physical stressors: ◦ Nutrient loading ◦ Unstable hydrology ◦ Habitat destruction Minnesota Pollution Control Agency staff evaluating invertebrate samples

 Macroinvertebrate community data can be used to: ◦ Monitor the condition of a wetland ◦ Determine the effectiveness of wetland mitigation ◦ Make decisions regarding permit issuance

 Aquatic macroinvertebrates fall mainly into 3 different phyla: ◦ Phylum Mollusca ◦ Phylum Annelida ◦ Phylum Arthropoda Scientific Classification: Kingdom Phylum Class Order Family Genus Species

 Clams and snails Helisoma sp. Physa sp. Stagnicola elodes L R

 Aquatic earthworms and leeches ◦ Aquatic earthworms are very similar to terrestrial earthworms – eat mud and small bits of organic bottom as they move through substrate.

 Class Malacostraca: Crayfish and Amphipods  Characteristics: ◦ Large diversity in this class ◦ 20-segmented body ◦ Two pairs of antennae ◦ Two pairs of maxillae

 Class: Insecta  3 distinct body regions ◦ Head ◦ Thorax ◦ Abdomen  2 pairs of wings  3 pairs of jointed legs

 1 pair of antennae  Compound eyes  Mouthparts consisting of: ◦ 1 pair of mandibles ◦ 1 pair of maxillae ◦ 1 labrum ◦ 1 labium

Merritt and Cummins 1996

Aquatic Insect Orders OrderExample CollembolaSpringtails EphemeropteraMayflies OdonataDragonflies and Damselflies PlecopteraStoneflies HemipteraTrue bugs MegalopteraAlderflies TrichopteraCaddisflies LepidopteraButterflies and Moths ColeopteraBeetles DipteraMosquitoes, Blackflies, Chironomids

 Common name: Mayflies  Nymph characteristics: ◦ Possess 2-3 tails at end of abdomen ◦ Gills arise from side of abdomen

 Adult characteristics: ◦ VERY short-lived  Do not feed – just reproduce, then die ◦ Occur in large swarms  Swarms are so large that they can be detected on radar! Swarms are so large that they can be detected on radar!

 Common name: Stoneflies  Larval characteristics: ◦ Each leg ends in 2 claws ◦ Possess 2 cerci at the end of abdomen ◦ Antennae typically 4-6 times the width of the head

 Common name: Caddisflies  Larval characteristics: ◦ Often possess 2 prolegs with hooks at tip of abdomen ◦ Can free-living or build complex casings ◦ Often have thread-like gills on abdomen

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 Common name: Dragonflies, Damselflies  Larval characteristics: ◦ Damselflies:  Delicate looking  3 caudal leaf or paddle-shaped gills at tip of abdomen ◦ Dragon flies:  Stout body, gills located inside abdomen tip

 Larvae have a HUGE, hinged lower jaw that can be extended to capture prey as large as fish! Larvae have a HUGE, hinged lower jaw that can be extended to capture prey as large as fish!

 Adult characteristics: ◦ Dragonflies:  Wings are held out to the side when at rest  Rear wings have a broader base than front pair ◦ Damselflies:  Wings are held above the body when at rest  Wing pairs of similar shape and size

 Common name: True bugs  Characteristics: ◦ Mouthparts are modified into a beak called a rostrum ◦ May be found with air bubble in the water ◦ 1 st pair of wings are modified into leathery coverings for hindwings (hemelytra)

Interesting facts:  Watch out in the water! Also known as toe-biters, these bugs will take a stab at unsuspecting humans swimming in ponds or lakes.  Rostrum operates by piercing the prey, ejecting digestive enzymes into the prey, and then sucking out the digested remains. ◦ Allows the bugs to feed on large prey, including snakes and small turtles.

 Common names: Mosquitoes, Blackflies, Craneflies, Chironomids  Larval characteristics: ◦ HUGE diversity, difficult to id any farther than family ◦ Lack jointed legs on the thorax ◦ Often have tubercules – small, fleshy appendages

 Many different “metrics” are used to describe macroinvertebrate communities.  Most common metric: ◦ Taxa richness: # of taxa in a community ◦ Prediction: As water quality ↓, taxa richness ↓  Related metric: ◦ EPT richness: # of Ephemeroptera, Plecoptera, and Trichoptera taxa in a community ◦ Thought to be more pollution sensitive

 Functional feeding groups ◦ Measures functioning rather than structure of the community ◦ Types of groups:  Scrapers - remove attached algae  Shredders – utilize large pieces of organic matter  Collectors – utilize small particles of organic matter, either by filtering or gathering them.  Predators – capture prey

Metric Predicted response to increasing perturbation % scrapersDecrease % collectorsVariable % predatorsVariable % shreddersDecrease % omnivores/scavengersIncrease

 Habitat and Behavior measures  Tolerance/Intolerance measures

 “Crawdad Dance”  Sweeping