Topic 3: Biodiversity and conservation
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3.1 Biodiversity and evolution
3.1.1Biodiversity levels
• Total diversity of living systems • Habitat diversity, species diversity, genetic diversity
3.1.2Diversity and resilience
• Components of diversity contribute to ecological system resilience
3.1.3Biodiversity from evolution
• Cumulative change in heritable characteristics
3.1.4Natural selection
• Mechanism driving evolutionary change • Operates continuously over billions of years
3.1.5Natural selection process
• Variation, overproduction, competition for limited resources • Differences in adaptation affect survival and reproduction rates • Heritable variation → increased frequency of advantageous genes
3.1.6Speciation
• Generation of new species through evolution • Population isolation → adaptation → inability to interbreed
3.1.7Species diversity components
• Richness: number of species in community • Evenness: similarity of population sizes
3.1.8Simpson's reciprocal index
• Quantitative measure of species diversity • Allows ecosystem comparison and monitoring change over time
3.1.9Biodiversity knowledge for conservation
• Knowledge of global and regional biodiversity is needed for the development of effective management strategies to conserve biodiversity • Include: how knowledge of biodiversity is gathered in the local region • This is likely to involve citizen science and the work of voluntary and government-funded agencies • The training of indigenous people and others, such as parabiologists, is also used to gather information for use in conservation management
3.2 Human impact on biodiversity
• Direct: overharvesting, poaching, illegal pet trade • Indirect: habitat loss, climate change, pollution, invasive alien species
• Most ecosystems subject to multiple impacts • Effects amplified when combined
• Reduce biodiversity through competition, predation, diseases/parasites
• Global conservation status assessment • Based on: population numbers, rate changes, breeding potential, geographic range, threats • Status ranks: least concern (LC) to extinct (EX)
• Publicizes species vulnerability • Allows selection of conservation priorities and management strategies
• Extinct species due to human activity • Critically endangered species • Species improved by intervention
• Overexploitation of shared natural resources • Tension between individual self-interest and sustainable development • Examples: fish stocks, ocean plastic pollution
3.3 Conservation and regeneration
• Aesthetic, ecological, economic, ethical, social
• Species-based: ex situ (zoos, botanic gardens, CITES, seed banks) • Habitat-based: in situ (national parks, reserves, sanctuaries)
• Both habitat and particular species considered • Flagship/keystone species used to justify habitat conservation
• UN treaty addressing species and habitat conservation • National strategies for conservation and sustainable use • Includes Nagoya Protocol (equitable sharing of genetic resources)
• Protect species by conserving natural environment • May require wild area protection or active management
• Understanding target species biology • Size and shape of conservation areas • Edge effects, wildlife corridors for connectivity • UNESCO biosphere reserves: pristine core, buffer zones, transition zones
• Regenerates natural processes in ecosystems • Methods: apex predator reintroduction, habitat connectivity, cessation of agriculture
• Reverse biodiversity decline • Operating within biodiversity planetary boundary • Individual, collective, national, international levels
• Environmental perspectives and value systems impact choices • Success depends on: community support, funding, education, legislation, research