All images from the FWS National Image Library unless otherwise noted'

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• All images from the FWS National Image Library
  unless otherwise noted.

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Ecosystems and Natural Communities

• Chapter 4

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Figure 4-1
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Figure 4-2
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• Ecosystem
• network involving the interactions of living and
  nonliving elements in a manner that sustains life
• plants and animals
• air, soil, water
• Biotic community
• living components
• Abiotic
• nonliving
• Biosphere
• part of Earth extending beneath Earths surface
  into the atmosphere where life flourishes

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Management Decisions with Ecosystems

• Adjust water levels to improve nesting cover for
  waterfowl
• habitat changes
• fish, amphibians
• birds, aquatic mammals

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Matter and Energy

• Carbon based life
• Photosynthesis
• Cellular respiration
• Food chains
• pathway materials flow through exosystems
• plants to decomposers
• Primary production
• energy incorporated into green plants by
  photosynthesis
• sun source of all energy

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• Second law of thermodynamics
• transformation of energy is NOT 100
• some last as heat
• metabolism
• 10 transfer to next level is standard
• between trophic levels
• feeding levels
• Consequences
• less energy is available at each successive
  trophic level
• length of a good chain is limited
• very little energy remains after three or four
  steps

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Figure 4-3 Biomass Pyramid on Isle Royal
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Range of Tolerance

• Range of tolerance
• ecological amplitude
• for each component of their environment
• when upper or lower optimal limits are exceeded
• organism experiences difficulties
• dies where critical physiological functions are
  reduced/stopped
• Steno-
• means narrow range
• Eury-
• means wide range of tolerance

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Figure 4-4 Relationship of Biological Activity
to a Gradient of Environmental Conditions
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Niche

• Niche
• unique role of organism in ecosystem
• emphasizes function within an ecosystem
• location and role in environment
• reduces the turmoil of competition
• Ecological equivalents
• organisms in different geographical areas that
  fulfill similar roles in their respective
  communities
• Organisms feeding on same food do NOT necessarily
  occupy the same nice
• time, location, method of feeding may vary
• Wildlife Managers must match habitats to niche
  requirements of a species
• especially for those with narrow limit of
  tolerance

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Figure 4-6
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Table 4-1 Forest Habitat Compositionspruce
grouse like pines/spruce ruffled grouse like
deciduous tree buds
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Natural Communities - Changes in Time Space

• Tundra
• Deciduous Forest
• Grassland
• Desert
• Rain Forest
• Coniferous Forest
• Chaparral

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Figure 4-7
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Table 4-2
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• Ecological Succession
• orderly progression through time of changes in
  community composition
• progresses through intermediate stages from
  pioneer to climax communities
• primary succession
• occurs when no community previously existed
• secondary
• takes place where there are remnants of previous
  community
• dynamic equilibrium
• constantly changing
• tilled field abandoned
• pioneer community of weeds
• annuals with large numbers of seeds
• annuals replaced by perennials

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Succession Wildlife Management

• Wildlife management
• manipulate habitat for the benefit of selected
  species
• bobwhite do best at early successional stages
• Tools to set back succession
• ax
• cow
• match
• plow
• herbicides
• Climax species
• caribou
• eat lichens growing in understory of mature
  trees, boreal forest

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Table 4-3 Climax Non-climax Communities
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Diversity and Stability

• Diversity
• number of species in a community
• Abundance
• numerical measure of a populations size
• Biomass
• amount of living mass in a defined part of an
  ecosystem
• Stability
• relative constancy in abundance of populations
• Argument
• Does diversity promote stability?
• Does stability promote diversity?

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• Symbiotic
• close relationship between two or more unrelated
  organisms
• Mutualism
• two organisms benefit each other
• lichen, part algae, part fungi
• environmental indicators absorb substances from
  atmosphere
• Diversity as Environmental Safeguard
• more species, less impact if one disappears
• Buffer species
• secondary foods that become of primary importance
  for maintenance of stability
• Trend toward decreased diversity
• due to human impact
• monocultures in agriculture

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• Wildlife Management
• does not maintain or regain diversity once
  present in natural communities
• hunting is primary management goal
• Varied Resiliency of ecosystems
• some ecosystems adapted to wide variations
• rainfall and temperature
• fire, insects
• invasive species
• synthetic chemical compounds
• Succession
• healing process
• some ecosystems dont recover as fast
• artic tundra, desert

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Summary

• Global ecosystem
• Producers
• Trophic Levels
• Consumers
• Decomposers
• Food webs
• Biotic Communities

• Diversity
• Niche
• Range of tolerance
• Biomes

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• All images from the FWS National Image Library
  unless otherwise noted.