Ecosystems at risk: vulnerability and resilience Flashcards Preview

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Flashcards in Ecosystems at risk: vulnerability and resilience Deck (10):

What are the factors affecting vulnerability and resilience? and the importance of dynamic equilibrium



ecosystem must function in this state of interconnections between biosphere, lithosphere, hydrosphere and atmosphere. If one sphere changes, all change as well --> if beyond limits= vulnerability


What is biodiversity? and 2 eg:

genetic, species, ecosystem diversity within a system

Genetic: variety in plants, animals and micro-organisms

Species: no. of species within each trophic level, more species --> more pathways of ecological processes, more resilient

Ecosystem: diversity within ecosystems, habitat difference, biotic community, ecological processes

Wetlands: flora --> not diverse, very specialised (saltmarsh, mangrove). Fauna --> lots of diversity, detritivores, bird species BOTH R/V

Reef: flora --> immense diversity, fauna --> lots RESILIENT


What is extent? and 2 eg:

size of ecosystem in question, larger in extent --> more resilient

wetlands: small extent, 58 ha VULNERABLE

reef: large, 348 000km2 RESILIENT


What is linkages? and 2 eg:

interdependence of species to survive: higher level of this, better chance to absorb change

wetlands: no specific, but heavily dependant on mangrove BOTH (more resilient)

reef: lots of variety, RESILIENT (both: Zoo X --> v)


What is location? and 2 eg:

depending on where the ecosystem is located, esp. if in extreme environments affects degree specialisation of species --> more vulnerable to change

wetlands: located in estuary, surrounded by urban development and no room to expand VULNERABLE

reef: proximity to coast, urban growth/mining and affected by El Nino bleaching events, cyclones VULNERABLE


What is maleability? and 2 eg:

difference between final recovery level and pre-stress --> bigger difference, less resilient

wetlands: worst polluted areas in city BOTH (resilient from human intervention, yet vulnerable from past land use)

reef: complicated by many threats, from multiple sources and climate change. never fully return to pre-stress VULNERABLE


What is amplitude? and 2 eg:

threshold beyond which ecosystem can no longer return to original state

wetlands: given proper management since 1988 but still BOTH (resilient from human intervention, yet vulnerable from past land use)

reef: reached limit with mass bleaching events, only getting worse with climate change /multiple threats VULNERABLE


What is elasticity? and 2 eg:

rate of recovery following stress event

wetlands: no benchmark and still suffering from past land use, limited knowledge on overall impacts --> ongoing scientific research BOTH (resilient from human intervention, yet vulnerable from past land use)

reef: low rate, slow to recover 12-15 years VULNERABLE


Natural stress impacts on 2 eg: (and rate of change)

salinity --> catastrophic, although adapted with less frequent precipitation/more intense rainfall can alter salinity completely --> mangroves need hypersaline conditions
tide --> gradual, adaptations to cope with ebb and flow of water, rising sea levels

cyclones --> catastrophic, major source of damage creating huge waves destroying coral reef, alter salinity levels (bring large freshwater amounts)
Crown of Thorns --> gradual, boom or bust organism (either small no. or large), with increased nutrients from runoff, eat coral polyps, inefficient predators/human killing, slow (giant triton snail eats one a week)


Human induced stress impacts on 2 eg: (and rate of change)

past land use --> gradual, industry chemical use (DDTs, oils) created by-product dioxins --> runoff affect bioaccumulation
straightening Powells creek --> catastrophic, heats up and loses oxygen, also stop deposition of nutrients/silt to mangroves (fast water velocity)

exclusion --> gradual, restrict public access of certain areas, allow to naturally regenerate
education --> gradual, through school excursions, signs change public perception --> know how important wetlands are

climate change --> catastrophic, many impacts, on organisms, rainfall, sea temperature, acidification
overfishing --> unsustainable practice, deplete resources, threatened by illegal fishers (foreign trawlers, recreational etc.)

Zoning plan --> special zones for human activity, protect for future generations (intergenerational), but also present to use too (intragenerational)
exclusion of certain islands --> vital for animal species (bird rookeries, turtle laying) and stop public access to minimise disruption and monitered