EVPP 550 Waterscape Ecology and Management

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EVPP 550Waterscape Ecology and Management

• Professor
• R. Christian Jones
• Fall 2007

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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

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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

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Adaptation to Flowing Water

• Anchoring
• Flattening of bodies to stay in boundary layer
• Suckers, hooks, silky secretions
• Ballast

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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)

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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

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Comparative Energy Flow in Streams

• New Hope Creek, NC
• Third order stream with more open canopy, but
  still allochthonous material is more important

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Comparative Energy Flow in Streams

• Thames River
• Larger stream with more varied sources of primary
  production

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Comparative Energy Flow in Streams

• Silver Spring
• Large underground source of clear water
• Almost all production is autochthonous

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Stream Energy Flow

• Importance of insects to stream food web is shown
  by experiments that substantially removed insects
  from the stream food web

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Stream Energy Flow

• Importance of autochthonous production in small
  to medium streams?
• Minshall (1978) argues that it has been
  underestimated

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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, 10-60 cm deep) In Great Basin
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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

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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

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Large Rivers

• In large rivers, interactions between main river
  channel and floodplain become increasingly
  important
• Lengthgt2000 km, Ordergt7

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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

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Large Rivers

• Many large rivers show a single strong annual
  discharge peak which inudates the floodplain
• Flood-pulse concept

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Large Rivers

• Flood pulse concept emphasizes lateral or
  latitudinal gradients whereas RCC emphasizes
  longitudinal processes

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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

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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

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Large Rivers

• Habitats within the floodplain
• Backwaters
• Lakes
• Wetlands

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Large Rivers Exchanges of Materials

• River brings
• Plant nutrients (NP), organic particulates,
  inorganic particles from upstream
• NP ? 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

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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

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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

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Large Rivers - Animals

• Timing of flood waters affects usefulness to
  differing groups of biota in temperate areas

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Origins of Lakes

• Glacial
• Tectonic
• Volcanic
• Solution
• Fluviatile
• Impoundments

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Origins of Lakes

• Glacial phenomena are responsible for the
  greatest number natural lakes esp the immense
  number of small lake basins

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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

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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

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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

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Origin of Lakes

• Moraine or outwash dams
• Back up water into an existing valley
• Finger Lakes, NY

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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

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Origin of Lakes

• Tectonic Activity (crustal instability and
  movement)
• Graben fault-trough rift lake
• Formed between two faults

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Origin of Lakes

• Some are symmetrical such as Lake Tahoe
• Some are assymetrical such as Lake Tanganyika

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Origin of Lakes

• The Worlds oldest and deepest lake Lake Baikal
  is a graben complex