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

4. 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

5. 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)

6. 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

7. Principles Life on earth depends on: A.Natural cycling of chemical elements B.Energy flow

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

9. Chemical Cycles

10. Carbon Cycle

11. Water Cycle

12. Nutrient Cycle

13. N-S Cycles

14. Box 11: The role of fungi Required Reading

15. 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 CO 2  warmer temperatures  more methane production in peat lands  higher greenhouse effect  higher temperatures

16. Positive Feedback

18. 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 CO 2  increased cloud cover;

19. Negative Feedback

21. Potential feedback mechanisms in climate change

22. 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

23. Properties of Ecological Systems

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

25. 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

26. 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

27. 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

29. 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

30. Energy Flow within Trophic Chains Plants Detritus HerbivoresPredators Detritus Respiration Energy

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

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

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

37. Box 31: North Slope of Alaska

38. Box 28: Harvest of Murres

39. 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

40. Toxicants: Large Scale Inputs

41. Toxicants: Biomagnification

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