1. EVPP 550 Waterscape Ecology and Management
Professor
R. Christian Jones
Fall 2007

2. Adaptation to Flowing Water
Life Cycles are often adaptive
Many aquatic insects are aerial as adults to facilitate dispersal and crossbreeding
Some species concentrate their growth phases in periods of favorable conditions (moderate temp, plenty of water and food) and revert to dormant stages (eggs, pupae) during other stages

3. Adaptation to Flowing Water
Feeding mechanisms:
Scrapers: radula in snails, mayfly nymphs use bristles
Filtering mechanisms:
Fringes of hairs on mouthparts and legs
Caddisfly Nets
Blackfly

4. Adaptation to Flowing Water
Anchoring
Flattening of bodies to stay in boundary layer
Suckers, hooks, silky secretions
Ballast

5. Adaptation to Flowing Water
Modes of existence (habits)
Skaters (water striders)
Divers (water boatmen and diving beetles)
Swimmers (streamlined mayfly nymphs)
Clingers (net-spinning caddisflies, blackflies)
Sprawlers (some mayflies and dragonflies)
Climbers (damselflies, mayflies, chironomids)
Burrowers (chironomids, oligochaetes, bivalves)

6. Comparative Energy Flow in Streams
Bear Brook
Wooded second order stream in New England
Dominated by allochthonous inputs from forest canopy directly and from upstream

7. Comparative Energy Flow in Streams
New Hope Creek, NC
Third order stream with more open canopy, but still allochthonous material is more important

8. Comparative Energy Flow in Streams
Thames River
Larger stream with more varied sources of primary production

9. Comparative Energy Flow in Streams
Silver Spring
Large underground source of clear water
Almost all production is autochthonous

10. Stream Energy Flow
Importance of insects to stream food web is shown by experiments that substantially removed insects from the stream food web

11. Stream Energy Flow
Importance of autochthonous production in small to medium streams?
Minshall (1978) argues that it has been underestimated

12. Stream Energy Flow
Streams in some areas have little or no canopy, eg prairie, desert, urban, farm
Example: Deep Creek, Idaho
Small stream (1-6 m wide, cm deep)
In Great Basin

13. Stream Energy Flow
In streams with deciduous canopy, during periods with no leaves, light reaching stream is substantial
Periphyton production tends to be highest in spring and fall when consumers are most active

14. Stream Energy Flow
Even in streams with relatively closed canopy and apparent low algal density, periphyton may be important
High rates of production may occur under low light (shade-adapted)
High rates of production may be masked by high rates of production (grazing rate ≈ production)
Periphyton are a high quality food source and important food supplement

15. Large Rivers
In large rivers, interactions between main river channel and floodplain become increasingly important
Length>2000 km, Order>7

16. Large Rivers Channel is deep and turbid
Substrate is fine and in constant motion
Upstream food supplies are of poor quality, best compounds have already been utilized
Many backwaters and side channels with slower flow
Flood plain inundation is relatively predictable so aquatic communities can adapt to this as a resource

17. Large Rivers
Many large rivers show a single strong annual discharge peak which inudates the floodplain
“Flood-pulse” concept

18. Large Rivers
Flood pulse concept emphasizes lateral or latitudinal gradients whereas RCC emphasizes longitudinal processes

19. Large Rivers Single large pulse inundates the entire flood plain
Land-water interface (littoral) is pushed to the edge of the floodplain
As year proceeds, the moving littoral (ATTZ) slowly edges back toward the channel margin
ATTZ-aquatic-terrestrial transition zone

20. Large Rivers The flood plain has high productivity due to:
High nutrient concentration
Shallow water depth
Low current velocity & resulting increase in transparency
Lots of edges

21. Large Rivers
Habitats within the floodplain:
Backwaters
Lakes
Wetlands

22. Large Rivers – Exchanges of Materials
River brings
Plant nutrients (N&P), organic particulates, inorganic particles from upstream
N&P  fuel high production
Particulates  build up flood plain, carry P
Flood plain contributes
Fresher CPOM, FPOM, DOM than upstream sources
Nursery ground for many invertebrate prey organisms
Many larger predator animals enter flood plain to feed

23. Large Rivers - Biota Plants Respond to water levels
Amazon plants grow fastest at rising water levels
At this time water and nutrient levels are high and no low DO stress that occurs later
Seed production coincides with peak O2 levels

24. Large Rivers - Biota Animals enter the flood plain to feed
On rising tide much of food consists of pollen, fruits, seeds, terrestrial insects dropping from the canopy
Spawning occurs near the beginning of the rising water
Larvae and juveniles feed in the flood plain, adults move back into the main channels

25. Large Rivers - Animals
Timing of flood waters affects usefulness to differing groups of biota in temperate areas

26. Origins of Lakes Glacial Tectonic Volcanic Solution Fluviatile
Impoundments

27. Origins of Lakes
Glacial phenomena are responsible for the greatest number natural lakes esp the immense number of small lake basins

28. Origins of Lakes
Glacial action in currently restricted to Antarctic, Greenland and high mountains, but during the Pleistocene glaciation, vast ice sheets covered much of the Northern hemisphere

29. Origins of Lakes Definitions:
Drift: accumulation of material directly or indirectly resulting from glacial action
Moraine: drift deposited directly by glacier either at its end (terminal) or underneath (ground)
Outwash: drift washed away from a glacier and deposited

30. Origins of Lakes Glacial Rock Basins
Lakes formed by direct glacial scour of rocky basins
Includes small lakes such as cirques formed at the head of glacial valleys
Also includes larger fjord lakes like Loch Ness and Lake Windermere

31. Origin of Lakes Moraine or outwash dams
Back up water into an existing valley
Finger Lakes, NY

32. Origin of Lakes Drift Basins
Irregularities in the ground moraine such as ice blocks left behind which then melt
Kettle lakes
Northern Wisconsin, Walden Pond
Vast number in flat glaciated areas

33. Origin of Lakes Tectonic Activity (crustal instability and movement)
Graben = fault-trough = rift lake
Formed between two faults

34. Origin of Lakes Some are symmetrical such as Lake Tahoe
Some are assymetrical such as Lake Tanganyika

35. Origin of Lakes
The World’s oldest and deepest lake – Lake Baikal is a graben complex