Sampling Biodiversity Using macroinvertebrates Assessing Aquatic Biodiversity

What is a Macroinvertebrate? “Macro” – big enough to see with the naked eye “Invertebrate” – no backbone These organisms represent the foundation of freshwater aquatic ecosystems Food sources for- Fish Birds Reptiles and Amphibians Diversity of Macroinvertebrate Life is an indicator of STREAM HEALTH

Benthic Macroinvertebrates? “Benthic” = Bottom Most Macros are in the LARVAL or Nymph stage of life cycle Egg  Larva/Nymph  Adult

Dragonfly Life cycle Dragonfly NYMPH

Tolerance to Pollution Different orders of macros have different levels of tolerance to water pollution: Pollution Intolerant- macros cannot tolerate any level of pollution- will die if Exposed Examples: Mayfly, stonefly, caddisfly Pollution Sensitive- can stand some pollution Scuds, Dragonfly Larvae Pollution tolerant- can live in very polluted waters Aquatic Worms, Leeches, Black Flies

Why Does biodiversity matter? The more types of macros we find  the higher the biodiversity  the healthier the aquatic ecosystem is What can we infer if we only found pollution Tolerant bugs in our stream?

Identifying Macros dichotomous key Use physical characteristics to narrow down choices You will get better the more you practice

PRACTICE Identifying Macros Number your Journal #1-5 For each photo- use the dichotomous Key to Determine Macro READY?

#1

#1- Stonefly Pollution Intolerant

#2

#2- Amphipod (Scud) Pollution Sensitive

#3

#3- Black Fly Pollution Tolerant

#4

#4- Crane Fly Pollution Sensitive

Adult Crane Fly- They DON’T Bite!

#5

#5- Dragonfly Pollution Sensitive

Sampling Method- Kick Net Find a riffle of a stream One Partner faces upstream with net poles in streambed, Net outstretched Other partner stands in front of net, upstream Disturb streambed- Rub rocks off in Water, Kick, Twist feet, dance The point is to dislodge macros from their home into the net Carefully lift net out of water with debris inside, bring to stream bank and layout flat Sort through your sample, place similar Macros in Ice cube tray w/ Water- ID and count macros

Where do the Macros live? Riffles Packets of clumped dead leaves (Leaf Packs) Under and On Rocks Stream bed Sediments (Sand, Clay, Silt) Try to sample sites where these habitats are available for best results

What do Macros eat? Shredders- eat decomposing organic matter (detritivores) Crayfish, caddisflies, stoneflies Collectors- filter-feeders and gatherers Net-building caddisflies, black fly larva, mayflies Grazers- algae on rocks or vegetation Snails, waterpennies Predators- eat other macros, tadpoles hellgrammites, dragonflies, damselflies

Why Sample the Riffles? Oxygen enters Water Macros have gills – need oxygenated water

Other data we will collect Air temperature (deg. C) Water temperature (deg. C) Stream depth (cm) Stream width (m) Current and Recent Weather- Rainfall Types of macro habitat present (check) – leaf packs, submerged logs, etc.

When is a good time to Sample? Spring and fall are optimal Be careful of private property and hunting season Be safe when working in water

Assessing Water Quality Identify different macros (scuds, mayflies, black flies, etc.) Tally how many of each type of macro there are- 6 scuds, 2 mayflies, 1 crane fly Using the biotic index assign a Number (1, 2, 3) based on pollution tolerance Pollution Intolerant = 3 Somewhat Sensitive= 2 Pollution tolerant = 1 add up all the biotic index numbers to get stream health score

Practice stations at lab tables calculating stream health score based on Sample Streams