Chapter 6: Ecosystems and Ecosystem Management

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Chapter 6 Ecosystems and Ecosystem Management
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Watershed

• The whole region or extent of land which
  contributes to the supply of a river, lake or
  ocean.

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Our Watershed
Elm Fork Trinity Watershed
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Bioindicator

• The presence, condition, and numbers of the types
  of fish, insects, algae, and plants that provide
  accurate information about the health of a
  specific body of water.
• By tracking changes, water systems can be
  identified that have undergone change due to
  stress placed upon the environment.

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Bioindicators

• Some bugs can't tolerate water pollution,
• We call these bugs pollution sensitive. 
• 12 points each
• MayflyCaddisflyWater PennyPlanarianDobsonflyS
  tonefly
• Other bugs are less sensitive to pollution...
• Eight points each
• Crayfish              DragonflyMussel
  Riffle Beetle AdultWhirligig
  DamselflyClam FishflySowbug
  Riffle Beetle Larva             Alderf
  ly DamselflyCraneflyDragonflyMuss
  el

• Some bugs can live in any kind of water.  We call
  these bugs pollution tolerant.
• Four points each
• LeechMidgeAquatic WormGilled SnailBlack
  FlyLunged Snail

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Osteichthyes

• The Clean Water Act (CWA) was based on several
  laws, (Federal Water Pollution Control Act of
  1972, Clean Water Act of 1977, and the Water
  Quality Act of 1987) and was created to identify
  and reduce pollution caused by industrial,
  government, and agricultural facilities.
• The Acts objective is to restore and maintain
  the chemical, physical, and biological integrity
  of the Nations waters through the use of
  credible bioindicators to evaluate the health of
  a body of water.

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EPA Case Study
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The Ecosystem Sustaining Life on Earth

• Sustaining life on Earth requires more than
  individuals
• Life is sustained by interactions of many
  organisms functioning together in ecosystems
• Physical and chemical environments

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Basic Characteristics of Ecosystems

• Ecosystems have several fundamental
  characteristics
• Structure
• Made up of two major parts
• Biotic or living (ecological community)
• Abiotic or non living (physical chemical
  environment)

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Basic Characteristics of Ecosystems

• Processes
• Cycling of chemical elements and flow of energy
• Change
• Undergo development through succession

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Basic Characteristics of Ecosystems

• For complete recycling of chemical elements to
  take place, several species must interact.
• Photosynthetic organisms produce sugar from
  carbon dioxide and water
• From sugar and inorganic compound they make other
  organic compounds (protein, woody tissue)
• Need decomposers to get back to inorganic
  compounds

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Basic Characteristics of Ecosystems

• At its simplest a community will have
• At least one species that is a producer
• Another species that is a decomposer
• Plus a fluid medium

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Ecological Communities

• Ecological community defined in two ways
• A set of interacting species found in the same
  place and functioning together to maintain life.
• Operational def all the species found in an
  area, whether or not they interact.

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Food Chains

• Energy, chemicals and some compounds are
  transferred from creature to creature along food
  chains (food webs).
• The linkage of who feeds on whom
• Grouped by trophic level
• of feeding levels away from original source of
  energy

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Trophic Levels

• First trophic level
• Use energy from the sun and carbon dioxide from
  the air to photosynthesizes
• Green plants, algae and certain bacteria
• Called autotrophs
• Second trophic level
• Organisms that feed on autotrophs
• Called herbivores

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Trophic Levels

• Third trophic level
• Feed directly on herbivores
• Called carnivores (meat eaters)
• Fourth trophic level
• Carnivores that feed on third-level carnivores
• Decomposers- feed on waste and dead organisms of
  all trophic levels

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A Terrestrial Food Chain

• Example North American Temperate Woodland
• 1st level- grasses, herbs and trees
• 2nd level- mice, pine borer and deer
• 3rd level- foxes, wolves, hawks and other
  predatory birds and insects
• 4th level- humans

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An Oceanic Food Chain

• Tend to have more trophic levels
• 1st level- planktonic algae and planktonic
  bacteria
• 2nd level- zooplankton and some fish
• 3rd level- fish and invertebrates feed on
  herbivores, baleen whales
• 4th levels- killer whales, predatory fish

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The Food Web of the Harp Seal

• Food webs are complex because most species feed
  on several trophic levels.
• Harp seal (shown at 5th level)
• Feeds on flatfish (4th level)
• But also feed on foods from 2nd 4th
• A species that feeds on several levels placed in
  a category one above the highest level it feeds
  on.

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Community Level Interactions

• Indirect and more complicated community wide
  affects species have on one another.
• Sea otter of the Pacific Ocean
• Came close to extinction because of over hunting
  for fur
• Feed on shellfish (abalone, sea urchins)
• Where sea otters abundant kelp beds abundant and
  few sea urchins
• Otters affects the abundance of kelp

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Community Level Interactions

• Sea otters have community level effect
• Where more kelp is present more habitat for many
  species
• Keystone species
• A species that has a large effect on its
  community or ecosystem
• Holistic view
• Ecological community is more than the sum of its
  parts

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How do you know when you have found an ecosystem?

• An ecosystem is the minimal entity that has the
  properties required to sustain life.
• Vary greatly in structural complexity and clarity
  of their boundaries.
• Differ is size, composition, proportion of
  non-biological constituents and degree of
  variation in time and space.

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Watershed

• Watershed
• Commonly used practical delineation of the
  boundary of an ecosystem
• Determined by topography
• United in terms of chemical cycling

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Ecosystem Management

• Ecosystem can be natural or artificial
• Can also be managed
• Agriculture
• Wildlife preserves
• Ecosystem concepts lies at the heart of the
  management of natural resources.