Terrestrial Ecology

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Terrestrial Ecology

• Introduction to ecology
• Competitive interactions_1
• Competitive interactions_2
• Predator-prey interactions
• Plant-herbivore interactions_1
• Plant-herbivore interactions_2
• More complicated ecological interactions

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Terrestrial Ecology

• Managing pest numbers
• Modifying pest behaviour

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What is ecology?

• As distinct from
• Evolution
• Physiology
• Genetics
• Behaviour

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What is ecology?
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What is ecology?
1. Studying interactions
2. Within between
3. At various levels
4. To understand (explain)
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Or

• Understanding biodiversity
• Why is there biodiversity?
• What affects it?
• How why is it affected?

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Ecology broader context
Physiology
Genetics
Ecology
Behaviour
Evolution
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Ecology broader context

• Maintaining homeostasis in
• deserts?
• estuaries?

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Ecology broader context

• Phylogeny
• Populations across environments
• Metapopulations?
• Separate populations?

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Ecology historical context

• Agriculture
• What causes plagues of insects?
• What increases crop yields and why?
• Human population growth
• Theoretical rates of increase?
• Misery and population size (Malthus)
• Natural history
• Observing the natural world

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Natural History vs. Ecology?

• Observing describing the natural world
• Applying the scientific method to test your ideas

Natural history observations
Explanation
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Ecology vs. Ecological Methods?
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General factors affecting distribution abundance

• History
• Environmental conditions
• Resources
• Interactions (intra- and interspecific)
• Rates of birth, death, migration

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History

• Where were their ancestors?
• Landmasses move
• Climate changes
• Landscapes change

• Animals may NOT be somewhere
• Havent got there
• Died out
• if region ? unsuitable

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History

• Early mammals

• Eutherians
• Marsupials
• Monotremes

• Opossum (Didelphis virginiana) South ? North
  America
• Brushtail possum (Trichosurus vulpecula)(naturall
  y) still confined to Australia

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Environmental conditions?

• Abiotic factors varying in space time
• Temperature, rel. humidity, salinity, pH
• Hazards (volcanoes, tornadoes, turbulence)
• Can be modified by organisms
• e.g. temperature by grass cover
• Cannot be consumed
• cf. resources
• Impose physiological constraints on living
• Ecophysiology
• how organisms interact with environmental
  conditions

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Environmental conditions

• Affect individuals

• Patterns vary

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Environmental conditions patterns of effects?
(a)
Examples?

• Temperature
• pH

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Example (a) effect of temperature
(a)
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Environmental conditions patterns of effects?

• Examples?

• toxins

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Environmental conditions patterns of effects?

• Examples?

• Essential micronutrients
• copper

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Example (b c) toxins micronutrients
Blidberg E. (2004) Effects of copper and
decreased salinity on survival rate and
development of Tridacna gigas larvae. Marine
Environmental Research, 58, 793-797.
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Resources?

• Things that are consumed
• cf. environmental conditions

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Resources?

• Include

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Resources

• Affect individuals

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Ecological niche (Hutchinson 1958)

• Conditions / resources essential for maintaining
  a viable population
• Each dimension represents a condition or
  resource
• ?n-dimensional hypervolume n-D

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How to maintain a viable population?

• Individuals must

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Ecological niche

• Fundamental niche
• Conditions Resources essential for maintaining
  a viable population
• Overall potential of a species

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Realised niche Can it get there?
Examples?
Rabbits in Australia - thriving
Wallabies in UK - thriving
Possums in NZ - thriving
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Realised niche effect of enemies?
Dingoes on mainland Australia devils extinct
3200y.a.
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Niche

• Depends on
• Conditions
• Resources
• Enemies

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(Why) is the concept of niche important ?

• Level of competition?
• ? niche overlap ? competition?
• Introductions extinctions?
• empty niche?
• niche overlap ? competition ? extinction?
• Role of species in ecosystems?
• Are all niches filled?
• Is biodiversity important for ecosystem
  processes? Are all current species essential?

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Main points

• Distribution abundance affected by
• History
• Environmental conditions
• Resources
• Interactions
• Births, deaths, migration
• Niche
• Fundamental
• Realised (add enemies)

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General References

• Attiwill P. Wilson B. (eds) (2003) Ecology an
  Australian Perspective. 1st edn. Melbourne,Oxford
  University Press.
• Begon M., Harper J. L. Townsend C. R. (1996)
  Ecology Individuals, Populations and
  Communities, 3rd edn. Blackwell Science Ltd,
  Malden, Massachusetts.
• Krebs C. J. (2001) Ecology the Experimental
  Analysis of Distribution and Abundance, 5th edn.
  Benjamin Cummings, San Francisco.

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