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Stream Ecology and Macroinvertebrate Sampling

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Presentation on theme: "Stream Ecology and Macroinvertebrate Sampling"— Presentation transcript:

1 Stream Ecology and Macroinvertebrate Sampling

2 What is a stream? A lotic habitat (flowing waters)
A transporter of inorganic and organic material A habitat for many species of fish, insects, birds, mammals, plants, and microrganisms stream is used to describe flowing waters (or lotic habitats). This includes rivers, creeks, branches and runs. When streams are impounded in a lake or reservoir (lentic habitats), the biological, chemical and physical characteristics of the stream often change significantly. Here we will only discuss lotic (flowing water) habitats (although habitats in large pools may have lentic properties). Streams remove inorganic and organic materials from the landscape by water transport. This process contributes to the shape and dimensions of the stream itself. The geologic history and characteristics underneath the watershed also strongly affect the morphology of the stream.

3 What is a Benthic Macroinvertebrate?
Why use them? Easy to collect and identify Some are indicator species Some are sedentary and have long life cycles, so can act as continuous monitors of water quality Macros are aquatic insects, mollusks and crustaceans Macros live in various stream habitats and derive their oxygen from the water Animals retained by a net with a mesh size greater than 1/5 of a mm

4 Macroinvertebrates are affected by:
- Resource availability - Pollution inputs (organic and inorganic) - Available habitat - Velocity and volume of water (flow) Why are they important? - They are the link in the aquatic food chain They eat algae, leaves, and other small macroinvertebrates, which are then eaten by larger animals like fish, who are eaten by birds, racoons, snakes, and people

5 Why Monitor Aquatic Systems?
Provides education about streams near us Assess the health of streams and our waterways Build local awareness about water quality Documents the quality of streams overtime Detect a pollution problem Determine places in need of restoration May influence decision-making of local, state, and federal governments The monitoring of streams and rivers yields an understanding of processes and patterns in the watersheds where people live, play and work.

6 What Is Point Source Pollution?
Industrial Discharge Sewage treatment plant Exposed leaking sewer pipe Regulated by EPD through a permitting process Pollutant source more easily identified (point to source)

7 What is Non-point Source Pollution?
Erosion Sediment Fertilizers, pesticides Animal wastes Runoff from roads and parking lots Illicit Spills and illegal dumping Leaking septic systems The #1 cause of water quality problems in North Carolina No easily identifiable source and everyone contributes

8 Biological Communities
Definition- a group of plants, animals, bacteria, and fungi living in a particular area Why is it important? It reflects the overall ecological integrity of a system because the organisms integrate the chemical and physical aspects of the environment Communities vary with microhabitat

9 What is Biomonitoring? Biological Monitoring Definition- The use of organisms and their biological responses to evaluate changes in the environment Why important? Reveals the effects of different pollutants or other changes in environmental changes. The presence of macroinvertebrates indicate both the the quality of water and habitat This data is often collected and used to assess the human impacts on a system

10 Kicknet Sampling Face it upstream Place rocks on net
Make sure there is a bow on the net Kick for one minute Ensure that water does not flow over the top of the net or escape around the sides Together bring sides together slowly and bring net out of H20 in a forward sweeping motion Kick net is facing upstream to the right. Note the bow in the net: this is important for creating a depositional area where insects can be accumulated. Weighting the net with rocks ensures that the net remains on the bottom of the stream. Washing large rocks by hand will greatly enhance capture success and is an important part of the procedure. When removing the kicknet from the water, ensure that no water washes over the top of the net. Bring the sides together and slowly bring the net out of the water in a forward sweeping motion. Sorting out the macroinvertebrates from the kicknet should take two people 20 minutes (see the next section). Organisms should be roughly sorted into general taxonomic groups (mayflies, stoneflies, etc) and placed into partitioned containers (e.g., ice trays) for further identification.

11 Sand/rock/gravel streambed
Stream Habitats Riffles Leaf packs Vegetated margins Woody debris Sand/rock/gravel streambed

12 Picking a site Suitable Riffles Small Safe to wade in
Will not wash water over top of kick net Not suitable riffle This is perhaps as small a stream as you might wish to sample for monitoring reasons (sample nothing smaller), but this stream is more than six feet wide and is actually a fourth order stream Pic 2- The riffle in the foreground of this picture is too large to safely or effectively wade for sampling. The section upstream of the white water (near the black pack) is more appropriate for sampling.

13 Leafpack Sampling Place pan underneath leaves Scrape material into pan
*+Leafpack accumulated behind a small log. Note the various stages of decomposition of leaves (some are green, some brown and partially decomposed). To collect this leafpack, a volunteer would carefully place a pan underneath the leaves and then gently scrape the material into the pan. Place pan underneath leaves Scrape material into pan Sort and identify the macroinvertebrates

14 Pollution-sensitive Macroinvertebrates
Caddisflies Hellegramites Mayfly Stoneflies Planarian Gilled snail Riffle beetle adult Water penny A healthy stream will have various pollution sensitive macroinvertebrates present

15 Stonefly Nymph Measure 8-15mm in length (not including tails) 2 tails
2 sets of wing pads Branched gills between legs on underside of body Yellow to brown in color; often patterned yellow and brown when mature Superficially similar to certain flattened mayfly nymphs, however stonefly nymphs always have two tails, prominent antennae, and two claws at the end of each leg. Stoneflies are not tolerant to low levels of dissolved oxygen and therefore prefer cold, swift-moving streams. The streamlined, flattened bodies of stonefly nymphs enable them to move about the rocky streambed in rapid currents

16 Mayfly Mature larvae measure to 3/4 inch in length (excluding tails)
Two rows of long hairs present on inside of front legs 2 or 3 tails Slender antennae The conspicuous hairs growing on the inner front legs are used for filtering food particles from the water. Brush-legged mayflies may be minnow like with a vertically oriented head and three tails (as pictured) or may be more flattened with a horizontally oriented head and two tails.

17 Antennae reduced and inconspicuous
Caddisflies Up to one inch in length Build distinctive cases made of sticks, rocks, sand, plant material and/or other debris Three pairs of legs Antennae reduced and inconspicuous

18 Hellegramites Measure 3/4 - 4 inches in length.
Body is elongate and somewhat flattened. Large pinching jaws. Lateral appendages along the length of the abdomen. Cotton-like gill tufts on underside of abdomen. Abdomen terminates in two small prolegs, each bearing two claws. Short inconspicuous antennae. Feed on other aquatic insects. Hellgrammites are usually found on the underside of large rocks in cool, slow-moving streams. Handle hellgrammites carefully, larger individuals may deliver a painful pinch!

19 Water Penny Measures 1/4 inch in length Flat disk-like body
Head and legs concealed from above 6 legs and branched gills on underside Prefers cold running water Water pennies prefer cold, fast-moving streams. Their smooth, flattened bodies enable them to resist the pull of the current. Water pennies are usually found on smooth rocks where they graze on attached algae

20 Riffle Beetle Adults Riffle beetles measure approximately 1/16 to
1/4 inch in length Body small, usually oval Legs are long Antennae are usually slender Riffle beetles walk slowly underwater, they do not swim on the surface

21 Gilled Snail Shell usually opens on right Shell opening covered by
a thin plate (operculum)

22 Pollution semi-tolerant Macroinvertebrates
Alderfly Clam or Mussel Cranefly Crayfish Damselfly Dragonfly Fishfly Aquatic beetles Sowbug Scud Watersnipe fly Wherligig beetle larvae

23 Dragonfly Larva Measure between 0.5-2.0 inches in length Large eyes
Two pairs of wing pads Large round or oval abdomen Abdomen terminates in three small pointed structures Can be readily distinguished from other species by the presence of a large jaw which is modified for grasping and covers the underside of the head Prefer cool still water, often found among vegetation and leaf packs or burrowed in sediment

24 Damselfly Nymph Measure 1/2 to 1 inch in length Large eyes
3 broad flattened gills at end of abdomen Abdomen usually much more narrow and slender than that of dragonflies Underside of head covered by a large jaw which is modified for grasping

25 Cranefly Larva Measure 1/3-2 inches in length
Plump caterpillar-like segmented body Head is usually retracted into the body Milky green to brown color Four finger-like lobes at back end of body

26 Sowbug Measure 5-20 mm in length. Clear whitish to pink in color.
Dorsoventrally flattened (side to side). Seven pairs of legs, the first two are modified for grasping. Found in shallow freshwater on rocks or detritus.

27 Scud Measure 5-20 mm in length. Clear whitish to pink in color.
Laterally flattened (top to bottom). Seven pairs of legs, the first two are modified for grasping. Found in shallow freshwater springs, streams, lakes and ponds. Most species feed on detritus. Scuds are an important food source for many fishes.

28 Crayfish Measure up to 6 inches in length
Have 5 pairs of walking legs, the first pair with large pinchers Resembles a small lobster Crayfish are usually active only at night. During the day they hide in burrows or under rocks. Crayfish are omnivorous, eating both plants and animals.

29 Pollution-tolerant macroinvertebrates
Aquatic worm Black Fly Leech Lunged snail Midge Fly Some macroinvertebrates can survive or even thrive in polluted water. An unhealthy stream may only have a few types of non-sensitive macroinvertebrates present

30 Midge fly Measure up to 1/2 inch in length Body small, cylindrical,
and slightly curved Occasionally deep red in color, otherwise variously colored Two small prolegs just posterior to head Frequently found in bottom sediments of lakes, streams, and ponds where they feed on deposited organic material

31 Black fly Measure to 1/2 inch in length
Body cylindrical and widest posteriorly Abdomen terminates in an attachment disc Head usually possesses fan-like appendages Blackfly larvae prefer cold running water and are usually found attached by the end of their abdomens to rocks, woody debris, or vegetation in the currents of rivers and streams.

32 Leech Measure 1.0 mm to 5.0 cm in length.
Typically dorsoventrally flattened. Always have 34 segments. Suckers at both ends. Leeches are common in warm protected waters of lakes, ponds, streams, and marshes. Leeches usually avoid light by hiding under rocks or among aquatic vegetation or detritus. Silty substrates are unsuitable for leeches because they cannot attach properly.

33 Aquatic Worm Measure 1-30 mm in length, but sometimes over 100 mm.
Clear whitish to pink in color. Body consists of 7 to 500 segments. Segments often have bristles or hairs. Tolerant of low dissolved oxygen concentrations. Found in silty substrates and among debris or detritus in pods, lakes, streams and rivers. Dense populations of Tubificids can often be found in organically polluted rivers. Approximately 200 species in North America

34 Lunged Snail Shell usually opens to the left Breathe Air No operculum

35 Calculate your results If you find: You may have:
Variety of macroinvertebrates, lots of each kind Healthy Stream Little variety, with many of each kind Water enriched with organic matter A variety of macroinvertebrates, but a few of each kind, or No macroinvertebrates but the stream appears clean Toxic pollution Few macroinvertebrates and the streambed is covered with sediment Poor habitat from sedimentation

36 “We monitor because we care; We care because we are informed;
We are informed because we monitor.” -- Cassie Champion

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