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Module 2 Biocomplexity of the North

Module 2 Biocomplexity of the North

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Module 2 Biocomplexity of the North

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  1. Module 2Biocomplexity of the North Dactylica arctica Xanthoria elegens Algae under Arctic sea ice Poripidia flavocaerulescens

  2. Objectives • Learning about feedback mechanisms • Using feedbacks to meet management goals • Properties of ecological systems • Material and energy cycles • Human-induced ecological changes • Notion of ecological health

  3. Terms and Concepts • Homeostasis • Maintenance by an organism of a constant internal environment, such as regulation of blood sugar level • Equilibrium • Steady state for a population, community, or environmental parameter

  4. Terms and Concepts • Chemical cycles • Temporal and spatial changes in the distribution of a chemical compound in the environment due to physical or biological processes • Energy flow • Transfer of energy from sun radiation, through food chains, and dissipation to the environment (subject to the 2 laws of thermodynamics)

  5. Terms and Concepts • Resiliency • The ability of a natural system to return to a state of equilibrium after a disturbance (similar to “environmental robustness”) • Carrying capacity • The level of a population that can be sustained in an ecological environment assuming no human exploitation: dynamic in nature

  6. Principles Life on earth depends on: • Natural cycling of chemical elements • Energy flow

  7. Principles No ecosystem can function without a source of energy, generally through photosynthesis

  8. Chemical Cycles

  9. Carbon Cycle

  10. Water Cycle

  11. Nutrient Cycle

  12. N-S Cycles

  13. Required Reading • Box11: The role of fungi

  14. Feedback Systems Positive feedback: An interaction that increases or amplifies the response of the system in which it is incorporated • Positive feedback increases change • E.g. Increased CO2  warmer temperatures  more methane production in peat lands  higher greenhouse effect  higher temperatures

  15. Positive Feedback

  16. Positive Feedback

  17. Feedback Systems Negative feedback • An interaction that reduces or dampens the response of the system in which it is incorporate • Stabilizing; tends to oppose change • E.g. Population regulation; increased CO2 increased cloud cover;

  18. Negative Feedback

  19. Negative Feedback

  20. Potential feedback mechanisms in climate change

  21. Using feedback systems to meet management goals • Increased harvest of caribou leads to lower caribou numbers, less competition for food, less predation, and higher caribou reproduction

  22. Properties of Ecological Systems

  23. Biological Organization • Individual • One whole organism • Individuals have size, shape, health, or condition • They grow, reproduce, and die over time

  24. Biological Organization • Population • A group of individuals of the same species occupying the same area at a given time • Populations have abundance, biomass, size, and age and sex class structures • They compete, exploit prey, and produce biomass

  25. Biological Organization • Community • The collection of all organisms that live in a specific region at a given time • Communities have biomass, diversity (evenness, richness), and trophic structure • Produce biomass, process materials, and change through succession over time

  26. Biological Organization • Ecosystem • All of the organisms in an area, together with the physical environment with which they interact • Ecosystems have biological as well as physical and chemical structure • They move energy, materials, and nutrients

  27. Energy Flow • Energy is a requirement for any ecosystems • The North receives less sun energy due to the earth’s orientation towards the sun (changes with season) • Ambient temperatures are lower in the Arctic, which means less primary productivity

  28. Energy Flow within Trophic Chains Detritus Detritus Detritus Energy Plants Herbivores Predators Respiration Respiration Respiration

  29. Arctic Monitoring and Assessment Program. 1997. Arctic Pollution Issues: A State of the Arctic Environment Report. [online] http://amap.no/. Oslo: AMAP.

  30. Ecological health in the Arctic • Functions: productivity, food chain integrity, biodiversity • Toxicology (contaminants)

  31. Stresses of Arctic Ecosystems • Global changes (e.g. climate) • Industrial developments • Human exploitation (new technologies)

  32. Box 31: North Slope of Alaska

  33. Box 28: Harvest of Murres

  34. Case Study: Snow Geese • Rapid expansion (26 million in N. Canada • Habitat Degradation (over grazing) • Conclusions: • South-North landscapes are connected • Humans’ influences at macro scales

  35. Toxicants: Large Scale Inputs

  36. Toxicants: Biomagnification

  37. Required Reading • Implementing the Precautionary Principle by P.L deFur and M. Kaszuba • Sections 1, 2, 3, 4.1, 5