A2 Geography-Biodiversity under threat

Genetic diversity- diversity of genes within a species. Can determine the degree of resistance to pests and diseases. Broad gene pool vital to combat diseases & climate change. Agro-ecosystems have been reduced by plant breeding to artificial monocultures(genetic erosion)
Species diversity- variety of plant/animal species in a given area(habitat)-measure of no of different organisms(species richness). More diverse ecosystems are able to withstand threats such as climate change. removal of key species has huge impact on functioning of an ecosystem e.g nutrient cycling & energy flows. Endemics(unique & rare species) important. Few factors limiting growth-high primary productivity leads to a complex and diverse food web with many ecological niches-leads to high biodiversity
Ecosystem diversity- variety of different ecosystems & habitats surrounding them in a given area- biotic & abiotic. Highest biodiverse ecosystems- tropical rainforest & coral reefs.- adds to value of goods & services. SSSI-wide variety of habitats within small reserve- high levels of ecodiversity.
factors influencing biodiversity. effect light availability, temperature, humidity, nutrient supply. Absence of limiting factors- high levels of primary productivity & energy produced leads to high biodiversity. Size of are- large-more species. local-natural disasters, hunting, fishing, slash & burn, eutrophication from high tech agriculture.
1. Physical- Climate e.g temp, rainfall, light; latitude, altitude & gradient; vegetation & rate of nutrient recycling; age,size & topography of area, islandness & endemism; climate change
2. Human- Level of protection/management, level of poverty, direct actions exploiting flora & fauna, hunting, fishing, over harvesting, clearance for agriculture-deforestation, growth of human population & rate of development/use of technology, local ecosystem factors-succession disturbance, competition/colonisation, dispersion rates. direct factors- hunting, indirect-climate change. Negative-threats & positive-conservation
hotspots-areas of high biodiversity. criteria- species richness, high levels of endemism, severe levels of threat from human action- environmental degradation.
1. mainly in tropical areas- LDCs-poverty-main threat.
2. Coral reefs-11 marine hotspots, 25% of worlds coral reefs. most marine hotspots adjacent to terrestrial hotspots- land based threats to pollution, over-fishing and tourism development. threats-bleaching from global warming.
value of ecosystems- provide materials-food,freshwater,shelter,fuel. human security(mitigating disaster impact), health(access to clean air & water)
1. Ecosystem services- Supporting- Nutrient cycling, Soil formation, Primary production. Provisioning(Goods)- Food, Freshwater, Wood, Fuel. Regulating- Climate regulation, flood regulation, disease regulation, water purification. Cultural- Aesthetic, Spiritual, Educational, Recreational.
2. Constituents of wellbeing- Freedom of choice and action Security- Personal safety, Secure resource access, Security from disasters. Material for life- Adequate livelihoods, sufficient nutritious food, Shelter, Access to goods. Health- Strength, Feeling well, access to clean air & water. Social relations- Social cohesion, Mutual respect, Ability to help others.
threats to biodiversity
1. WRI- ecosystem scorecard- shows conditions of worlds major ecosystems & ability to provide future goods & services. Records freshwater ecosystems as the most eco-stressed
2. WWF- Living planet index- monitoring populations of representative animal species in forests, freshwaters and marine ecosystems. Grasslands recently added.
3. IUCN- Annual red list of endangered species- Placed in 1/10 categories from extinct/endangered-vunerable-little concern. Extinction hotspots-tropical rain forests, grasslands, polar & small island environments. Species with large body vulnerable to hunting, species with low rates of increase, poor dispersal & migration ability easily predated by alien species/ if perceived as a nuisance by humans. Feshwater ecosystems have highest percentage of threatened species.- reptiles & amphibians
4. MEA- UN Environment programme- Large-scale survey across 13 major ecosystems- world drylands(tropical grasslands) under greatest overall threat. Freshwater & marine ecosystems under greatest threat from hypoxia & eutrophication- could lead to ecosystem collapse. Deforestation of rain forests highly concentrated in brazil & Indonesia- 80% of destruction.
5. GBO- Global Biodiversity Outlook.- Assesses current status & trends of biodiversity to celebrate international Year of biodiversity-2010
6. freshwater ecosystems under greatest overall threat & drylands(tropical grassland) under greatest threat in future. climate change biggest threat in future. Amphibians & reptiles(1/3 in danger of extinction),Mammals(1/4), Birds(1/8). Some species emphasised(polar bears) to attract conservation funding- keystone species(bees) ignored. Endemic species- uniqueness & rarity (Galapagos islands). Global scale threats-server,widespread, long term effects on ecosystem functioning(nutrient cycling, energy flows) Local threats-short term,localised. Some natural threats triggered by humans. Destruction-loss in quantity. Degradation-loss in quality.
7. Global threats- Accelerated soil erosion, Desertification, deforestation, global scale pollution e.g acid rain, Ozone depletion, Global warming, Disease
8. Local threats- Hazard impact, Wildfires, Habitat conversion & fragmentation, Over-harvesting/fishing, Recreational impacts, Opencast mining, Eutrophication & local pollution, Invasive species.
causes of changes to ecosystems
1. Root/underlying causes- macroeconomic policies-role of TNCs & trade policies; Social change & development( demands for resources); Demographic changes- higher demand for food/fuel; Public policies- disregard for locals; Commercial markets(hardwood/traditional medicines); North-South divide-poverty & inequality, force people to hunt for food/kill animals (sell ivory)
2. Primary causes- Over-harvesting; Exploitation of wild resources; Habitat loss(deforestation/logging/agriculture/urbanisation); Introduction of alien species; Pollution(oil/pesticides/acid rain); Global climate change- changes in food supply, impact on arctic areas, desiccation of water.
Impact of threats on ecosystem processes
1. energy flows- trophic levels-energy lost through respiration & amount of biomass decreases
  1. Eutrophication- algal blooms that block out light & prevent primary producers photosynthesising & toxic conditions that can effect food chain.
    1. El Nino-warm water-reduces phytoplankton-lack of food for fish
      1. Over harvesting of fish, birds feeding on them suffer
        Alien species 'take over' at various trophic levels- no native predator e.g hedgehogs-Outer Hebrides
        over-hunting of seals/otters- impacts further down food chain-overpopulation & starvation further up food chain
2. Nutrient cycling
  1. human activities can have impact on size of store- deforestation, over cultivation, soil erosion. Indirect- pollution e.g acid rain. humans add nutrients by fertilisation of soil- lead to eutrophication
  2. eutrophication-excessive richness of nutrients in a lake or other body of water, frequently due to run-off from the land, which causes a dense growth of plant life.
Managing biodiversity
1. Sustainable yield- safe level of harvest that can be hunted/caught/utilised without detriment to the sustainable management of an ecosystem.
  1. sustainable management allows resources to be used without compromising its worth for future generations
  2. Maximum sustainable yield- greatest harvest that could be taken indefinitely and leave systems in tact. only exceeded by commercial activities.
  3. Optimum sustainable yield- used as compromise as it is a lower level of yield and will not destroy aesthetic/recreational value of the ecosystem but will allow multi use for the maximum benefit of the whole community.
  4. sustainable yield used by managers to keep trophic levels of an ecosystem in balance e.g culling.
  5. Used in extractive reserves- e.g CAMPFIRE scheme Zimbabwe- hunting 'big game' permitted as a means of sustainable income for tribal communities providing levels of wildlife are sufficient(above optimum sustainable yield)- so wildlife tourism isn't damaged.- Licenced hunting- some say profit will get in the way
2. key players in biodiversity management- conflicts between exploitation of biodiversity for its goods and conservation for its future use. Max rates of exploitation occurring in countries experiencing rapid economic growth e.g china
  1. Individual farmers- Manage environment for food consumption- now subsidised to deliver environmentally friendly farming, adding to biodiversity.
  2. Individual campaigners- Justice to save rainforest e.g Sting in the Amazon
  3. Individual consumers- Make decisions about their consumption, whether to use environmental friendly products or to be ecotourists to conserve biodiversity.
  4. Artists,painters, writers- provide imaged & literature to amok people aware of the issue e.g Rachel carson on degradation of marine environment
  5. local communities- develop sustainable management and work together to save local ecosystems using bottom up schemes to resolve conflicts e.g Mangrove reserve St Lucia
  6. Campaigning NGOs- Greenpeace e.g Save the whale, RSPB
  7. NGOs scientific research- support of conservation and sustainable management schemes such as WWF
  8. local governments- manage local reserves in cooperation with wildlife trust and support biodiversity action plans
  9. National Governments e.g UK- DEFRA- provide well managed countryside and conserve wildlife. Natural England responsible for designating and administering National Nature reserves, SSSIs and AONBs
  10. TNCs- have environmental reports and decisions concerning locations to exploit can have huge impact on biodiversity in rainforest locations (logging/mining.biofuels). Collecting wild plants for pharmaceutical research can effect gene pool. TNCs cash sponsor biodiversity/conservation schemes & promote biodiversity
  11. International organisations- Global NGOs e.g World Conservation Union operate as think tanks & provide data & administer schemes such as Biosphere reserves and World Heritage sites
  12. UNEP/UNESCO- Carry out research, exchange ideas, provide information on biodiversity- big role in Millennium ecosystems assessment. Set up conferences for world treaties/ administer agreements
  13. Scientists & researchers- work for a variety of organisations- NGOs to international organisations & agencies- provide research data for management of biodiversity- based in universities.
3. Conservation
  1. what to conserve
    1. hotspot strategy- prioritises most threatened, high-quality areas. eco-region strategy-conserves representative ecosystems. fundraising favours more popular not keystone species
  2. how to conserve
    1. sustainable development now favours total protection.. total protection-Scientific reserve-(no access), Wildlife reserves & parks,Community wildlife management, Extractive reserves, Economic development integrated into conservation, tolerant forest management, Exploitation with token protection. ----Eco-reserves- insitu conservation alongside ex-situ(gene banks,zoos) to save endangered species.
  3. mechanics
    1. conflict between top-down global strategies and local initiatives. Indigenous people favour biodiversity- rely on it for subsistence.- lessened by plans from 2010 world yr of Biodiversity- integrated planning at variety of scales. LEDC & MEDC tensions- who pays for conservation- LEDC lower costs but money comes from aid & investment
4. ecofutures
  1. MEA- Global orchestration, Order from strength, Adapting mosaic, Techno garden
  2. Living planet report- Buisiness as usual, Slow shift to sustainability, Rapid reduction,radical solution, Shrink & shave
  3. GLOBIO- Markets first, Policy first, Security first, Sustainability first.
Synoptic links
1. links to other units - unit 1-world at risk- impact of climate change on Arctic & other ecosystems, Unit 3- Water conflicts- diminishing water quantity and quality, impact of energy exploitation. Impacts of technology use, impacts of development on ecosystems. Unit 4- Consuming the rural landscape- Impact of tourism on biodiversity, in fragile/vunerable areas e.g Galapagos
2. Links to wider global issues- Conservation v exploitation- need for sustainable approach. Global warming & impact on biodiversity- concern for indigenous communities who depend on biodiversity for existence, Development gap- contrasting issues & attitudes to biodiversity.

Siguiente

A2 Geography-Biodiversity under threat

Descripción

Resumen del Recurso

Similar

	Creado por sophielee0909 hace más de 10 años