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Ecosystems, Human Population and Development, Wild Species and…

- - - - tertiary consumer
        
        secondary consumer
        
        primary consumer
        
        primary producer
    - - scavengers
      - decomposers
- - - - Secondary: area cleared by fire, human activity, or flooding - is reinvaded by plants and animals from another ecosystem
      - Aquatic: soil particles eroded from land/plant detritus build up in ponds and lakes, eventually filling them
      - Primary: area lacking plants and soil is initially invaded by plants when soil forms (only rocks) (moss covered rocks)
      - Fire and Succession: some pine species require fire
        
        Resilience: ability of ecosystems to return to normal after disturbance
        
        Tipping Point: situation in human impacted ecosystem where small action catalyzes major change in system state
- - - - Demographers
- - - - Replacement-level fertility: fertility rate replacing population of parents
  - - - land ownership by wealthy - needs reform
      - intensifying cultivation - small farms cannot support families
      - opening up new lands - destroy ecosystems
      - resource exploitation
      - illicit activities
      - migration
- - - - (S) stewardship
- - - - Habitat loss
      - Over-exploitation
      - Introduction of invasive species
      - Population (humans)
      - Pollution
    - - intrusion of other species
        
        organisms not native to area that cause env. damage
        
        can be accidental, deliberate, or gradual / overtime
        
        what can we do?
        
        enact laws
        
        prevent establishment
        
        remedy situation
      - simplification - removing parts of ecosystems
      - fragmentation - highways
      - conversion - slash and burn agriculture
    - - biological: pathogens, parasites
      - physical: sediments, light, noise, thermal
      - chemical: nutrients, endocrine disruptors, compounds, industrial waste
    - - over harvesting of particular species
      - accounts for 23% of recent extinctions
        
        illegal trade in exotics
        
        greed -> monetary reasons and gains
- - - - Conservation: management and regulation of ecosystem use
      - Preservation: ensure continuity of ecosystems and species, regardless of potential utility
    - - precautionary principle: if you don't know the #, back off exploitation
      - common-pool resources: may be a problem - "Tragedy of the Commons"
      - optimal population: # of species you can harvest sustainably
    - - private ownership
      - commercial ownsership
      - state ownership
      - open access (over exploitation)
- - - - used for production of wood
      - 13.5% national parks or reserves (increasing)
      - deforestation rate 7.3 million HA/yr - lower than 1990 (18%)
      - role in climate change - carbon sequestration
      - 2005 forest cover 30% of total land area
      - insects and pests are increasing forest damage - related to climate change
    - - soil erosion increased
      - alters hydrology
      - biodiversity reduced
      - CO2 sequential loss
      - reduction in nutrients and biomass
      - productivity reduced
  - - - selective cutting
      - shelter-wood cutting
  - - - row crops / pastures
      - foremost cause of deforestization
    - - sustainable forest managements
      - conservation of biodiverse areas
      - setting aside reserves for food
      - preservation as national heritage
      - put in control of indigenous villages
  - - - 52% MSY, 16% over exploited, 8% depleted
      - plastic pollution, bottom trawling
      - 1970 - over fishing
    - - growing in developing countries
      - accelerate decline of fisheries (Eutrophication, disease)
      - Open Ocean Aquaculture: farming coastal species in ocean several miles from shoreline