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Studying Ecology at Different Levels of Organization

Lori Spindler

April 9th, 2016

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Keystone Topics in ecology:

  • BIO.B.4.1.1 Describe the levels of ecological organization (i.e., organism, population, community, ecosystem, biome, and biosphere)
  • BIO.B.4.1.2 Describe characteristic biotic and abiotic components of aquatic and terrestrial ecosystems.
  • BIO.B.4.2.1 Describe how energy flows through an ecosystem (e.g., food chains, food webs, energy pyramids)
  • BIO.B.4.2.2 Describe biotic interactions in an ecosystem (e.g., competition, predation, symbiosis)
  • BIO.B.4.2.3 Describe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle)
  • BIO.B.4.2.4 Describe how ecosystems change in response to natural and human disturbances (e.g., climate changes, introduction of nonnative species, pollution, fires)

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Levels of Ecological Organization

  • Individual
  • Population
  • Community
  • Ecosystem
  • Biome
  • Biosphere

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Population Ecology

  • Population: all the members of a species that live together at one time
  • Population Ecology: the study of what factors affect a population and why a population changes over time.

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Some Big Questions: Population Ecology

  • How do organisms make movement decisions in relation to dispersal, migration, foraging or mate search?
  • What are the evolutionary and ecological mechanisms that govern species’ range margins?
  • How can we upscale detailed processes at the level of individuals into patterns at the population scale?
  • Why are some species more vulnerable to extinction than others?

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W.J. Sutherland et. al. 2013. Identification of 100 Fundamental Ecological Questions. Journal of Ecology 101: 58-67.

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Prima Donna Species Just Has To Have

Every Part Of Natural Habitat Intact

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http://www.theonion.com/article/prima-donna-species-just-has-have-every-part-natur-52486

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Community Ecology

  • Community: all the organisms interacting in an area
  • Community Ecology: the study of factors that influence biodiversity, community structure, and the distribution and abundance of species. These factors include interactions with the abiotic world and the diverse array of interactions that occur between species.

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Species Interactions

  • Predation
  • Herbivory
  • Parasitism
  • Competition
  • Mutualism

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              • Hornworm caterpillar eats a tobacco plant. Parasitoid wasps lay eggs on the caterpillar and the pupae eat the caterpillar. The plant can release chemicals that attract the wasps.

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Some Big Questions: Community Ecology

  • Why do some places contain more species than others?
  • Is there competition in nature?
  • When, if ever, can the combined effect of many weak interactions, which are difficult to measure, be greater than the few strong ones we can easily measure?
  • How does species loss affect the extinction risk of the remaining species?
  • How do resource pulses affect resource use and interactions between organisms?

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Bamboo Reproduction: A resource pulse

  • Melocanna baccifera bamboo set seed in synchronous every 48 years.
  • They produce so many seeds that all the animals that eat the seeds have more than they can ever eat.
  • Populations of rats and other seed predators increase for a few years, but decline drastically before the next time the bamboos reproduce.

http://www.pbs.org/wgbh/nova/nature/plant-vs-predator.html

Dan Janzen

Melocanna baccifera seed pods

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Ecosystem Ecology

  • Ecosystem: all of the organisms and nonliving environment found in a particular place
  • Ecosystem Ecology: is the study of the living and nonliving components within the environment, how these factors interact with each other, and how both natural and human-induced changes affect how they function. 

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  • Ecosystems are often used interchangeably with biomes, eg. Temperate forest, tundra�

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Some Big Questions: Ecosystem Ecology

  • Which factors and mechanisms determine the resilience of ecosystems to external perturbations and how do we measure resilience?
  • To what extent is biotic invasion and native species loss creating ecosystems with altered properties?
  • How is ecosystem function altered under realistic scenarios of biodiversity change?
  • What are the major feedbacks and interactions between the Earth’s ecosystems and the atmosphere under a changing climate?
  • How do natural communities respond to increased frequencies of extreme weather events predicted under global climate change?

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What do we measure at the ecosystem level?

  • Very small things
    • Nutrient cycling
    • Photosynthesis
  • Very large things
    • Images of large areas
    • Long term patterns of temperature, precipitation and air currents

FACE (free air CO2 enrichment experiment

At Duke University

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Characterization of forest ecosystem functioning using imaging spectroscopy and thermal IR imagery

17.07.2013, 15:49 (GMT) by Shawn Serbin

Aditya Singh Brenden McNeil John Couture Clayton Kingdon Eric Kruger Philip Townsend Elizabeth Ainsworth Jeff Skoneczka

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