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Natural History of Stream Invertebrates: Using and Making Sense of Biotic Indices, and Beyond

Natural History of Stream Invertebrates: Using and Making Sense of Biotic Indices, and Beyond. Natural History. The study and description of organisms and natural objects, especially their origins, evolution, and interrelationships. caddisfly. sowbug. Natural History.

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Natural History of Stream Invertebrates: Using and Making Sense of Biotic Indices, and Beyond

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  1. Natural History of Stream Invertebrates: Using and Making Sense of Biotic Indices, and Beyond

  2. Natural History • The study and description of organisms and natural objects, especially their origins, evolution, and interrelationships caddisfly sowbug

  3. Natural History • Some examples related to aquatic macroinvertebrates might include: • Ecology (relationships between living organisms and the non-living components of the environment in which they live) • Behavior • Functional feeding groups

  4. What Problems Must Macroinvertebrates Solve Because They Live In Streams? • Aqueous medium (tough to get O2) • Medium that is generally moving upstream-downstream • Diel variation in physio-chemical characteristics • Seasonal variation in hydrology • Connected to upstream conditions • Linked to land-water interface black flies

  5. Feeding Groups or Guilds • Shredders - Coarse woody or plant associated materials • Filtering Collectors - Suspended particulates, microbes, phytoplankton • Gathering Collectors - Deposited particulates • Grazers/Scrapers - Peryiphyton & fungi • Predators - especially invertebrates caddisfly stonefly

  6. Some Guiding Principles for Classification • Everyone can classify objects • Ways macroinvertebrates may be classified: • Functional feeding groups • Morphology • Locomotion • Microhabitat • Type of metamorphosis • Means of obtaining oxygen • Need for oxygen / Ability of stream to provide that oxygen net spinning caddisfly

  7. Biotic Indices • A way to classify based on macroinvertebrates’ tolerance to pollution • Generally this means organic pollution • Or that which affects oxygen levels in the stream

  8. Biotic Indices • Some organisms require water with a lot of oxygen in it • Others have adaptations to obtaining the oxygen they need

  9. Adaptations for Obtaining Oxygen Morphological • Tubes • Soft tissue between segments & gills • Hair-like/Plate-like wings Behavioral • Body pumping • Swimming to surface • Construct burrows or tubes

  10. Biotic Indices • Assign pollution tolerance values to organisms based on their oxygen needs • Order level • Fairly Simple: Excellent, Good, Fair, Poor • Tolerance values 1, 2, 3 and 4 # Group 1 * tolerance value (4)= # Group 2 * tolerance value (3)= # Group 3 * tolerance value (2)= # Group 4 * tolerance value (1)= SUM A SUM B • SUM B/SUM A = Biotic Index Score

  11. Biotic Indices • More tricky: Excellent, Very Good, Good, Fair, Poor, Very Poor • Weighted average: Each individual is counted (rather than just counting types) • Tolerance values 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 • If 100 organisms in sample… Number of inverts in family * tolerance 1 *9 = 9 10 *8 = 80 16 *7 = 112 14 *6 = 84 5 *5 = 25 39 *4 = 156 5 *3 = 15 10 *2 = 20 100 501 • Answer: 501/100 = 5.01 • Gives specific types of macroinvertebrates individual credit for being in the stream

  12. Diversity of Families of Aquatic Insects in Wisconsin • Generally find 10 Orders • Approximately 89 Families water penny riffle beetle

  13. What are tolerances, feeding strategies, and presence of different families in Wisconsin streams like?

  14. Mayflies use abdominal gills to obtain oxygen Page 23

  15. Representative Mayflies armored mayfly flathead mayfly Hexagenia prong gill mayfly adult

  16. Dragonflies obtain oxygen through soft tissue between plates; Damselflies use leaf-like abdominal gills Page 23

  17. Representative Dragonflies & Damselflies broadwing damselfly larva darner dragonfly larva darner dragonfly adult broadwing damselfly adult

  18. Stoneflies use thoracic gills to obtain oxygen

  19. Representative Stoneflies perlodid stonefly common stonefly

  20. True bugs may use atmospheric oxygen or may use hair-like or tube-like modifications on their abdomens

  21. Representative True Bugs giant water bug water strider water scorpion back swimmer

  22. Dobsonflies, fishflies, hellgrammites, and alderflies obtain oxygen through diffusion across soft tissue

  23. Spongillaflies obtain oxygen through diffusion across soft tissue

  24. Representative Hellgrammites or Alderflies (Top) & Spongillaflies (Bottom) hellgrammite Alderfly larva spongillafly adult alderfly

  25. Caddisflies obtain oxygen through diffusion across soft tissues and sometimes with gills and pumping water through case

  26. Caddisflies obtain oxygen through diffusion across soft tissues and sometimes with gills and pumping water through case

  27. Representative Caddisflies humpless casemaker caddisfly saddlecase maker caddisfly net spinning caddisfly

  28. Aquatic moths obtain oxygen through diffusion across soft tissue

  29. Beetles obtain oxygen through diffusion across soft tissues and from the atmosphere through modified hairs and plate-like wings

  30. Representative Beetles Riffle beetle adult

  31. Flies obtain oxygen through diffusion across soft tissues including abdominal gills and atmospheric oxygen through breathing tubes

  32. Flies obtain oxygen through diffusion across soft tissues including abdominal gills and atmospheric oxygen through breathing tubes

  33. Representative Flies midge larva cranefly larva midge adult

  34. Long term sampling

  35. Biotic Indices aren’t the only solution • Diversity indices • Richness (# species) • Feeding guilds • Don’t forget to think about scale…

  36. Figure 2. Scale of Sampling and Analysis in Streams Ecosystem/Biome Watershed Ecosystem Reach Community/Ecosystem Pool-Riffle Sequence Hours Days Weeks Months Years Decades Centuries Population/Community Microhabitat Individual Organism, Particle or Grain Millimeters Meters Kilometers Sq. Kilometers

  37. Thought Question: What spatial and temporal scale would you choose to sample to determine changes in populations (number of individuals of the same species in a given area)?

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