Presentation on theme: "Prospects for Biodiversity"— Presentation transcript:
1Prospects for Biodiversity Author: Martin JenkinsSummary: Chase MahoneyCritique: Asa Angeles
2Introduction 9,000,000,000 people Imagine their impact. “What will be the state of the world’s biodiversity in 2050?”Prospects for Biodiversity offers an answer to this question.
3Overview Assumptions for extrapolation Human influences and their impactsTerrestrial EcosystemsAquatic EcosystemsDo these impacts matter?
4Assumptions for Extrapolation United Nations global population estimation9 Billion (2050)6-7 Billion (2003)The human race will conduct its affairs in much the same manner as today.Intergovernmental Panel on Climate Change Scenarios1oC to 2oC increase in average surface temperature.100 to 200 ppm increase in CO2 concentration.
5Major Human Influences on Land Habitat conversionClearing land for farmingIntensificationAt least 120 ha by 2030By 2050 much moreSouth America and sub-Sahara AfricaMost biologically diverse regions in the world.Disproportionate loss in biodiversity
6Major Human Influences on Land Habitat conversionClearing land for farmingDense tropical forest -> Fragmented/DegradedResemble temperate forests of North America350 species of avifauna (3.5%) will become extinct.Surviving species live in heavily protected managed areas.
7Major Human Influences on Aquatic Ecosystems Habitat ConversionDestruction by siltationLand runoffCoastal developmentPollutionLarge-scale Hydroengineering
8Major Human Influences on Aquatic Ecosystems Habitat ConversionFresh water biodiversity has suffered the heaviest losses over the last 30 years.These losses are expected to continueCoral Reef destruction
9Major Human Influences on Aquatic Ecosystems Exploitation of wild resourcesDirect exploitation through fishingCurrent rates lead to extinctionLarge species and top marine predators scarce or extinct.
10Does it Matter?Ecologists and Conservationists struggle to demonstrate benefits of diverse intact systems.Diverse species-rich systemsIntensively managed systems of nonnative species (farms)
11Does it Matter? Benefits are marginal and local Forest destruction Few cases have shown benefits of natural systemsForest destructionInfertile unusable land has obvious impacts on human existence.Replacement shows no negative impacts.
12Does it Matter?Experts agree most large terrestrial species are extinct as result of human influence.40,000 to 50,000 yearsSystems we consider natural aren’t so.Don’t show catastrophic consequences.
13Does it Matter? Real life example 38 species of avifauna existed in New Zealand.9 exist todayMost of which are endangeredHuge loss of biodiversityNo signs of suffering from a crisis.On what grounds can we base our belief that similar losses will result in crisis in other areas.
14Does it Matter? Still may not abuse the biosphere indefinitely. Unforeseen thresholdCatastrophic consequencesMore likely cause of catastrophic consequences will be abrupt climate shifts.May begin with manipulation and abuse of the biosphere.
15Conclusion Jenkins scenario assumptions ClimatePopulationSimilar method of conductHuman actions have direct influences on surrounding ecosystems.Losses in biodiversity do not have immediate negative impacts on human existence.Still be aware our impact may eventually trigger other catastrophic events.
16Prospects for Biodiversity By Martin JenkinsSummary: Chase MahoneyCritique: Asa S. Angeles
18Positive Critique Evidence 24 citations, including links to web sources
19Living Planet Index282 species195 species217 species
20Other Good Aspects of the Article Honest tone; mostly not over-dramatizedSays estimating extinction rates is difficultAdmits that scientists struggle to show human benefits from “intact” wild systemsNew Zealand went from 38 to 9 species of birds in a few centuries, but does not sufferThe future will probably be this way
21Constructive Criticism Minor: Of the 24 citations, 7 are Science articlesHow much does it matter?Says “natural” systems that really aren’t natural still function (recall New Zealand)But somewhat dramatizes at the end: “…some threshold may be crossed, with unforeseeable but probably catastrophic consequences for humans.”Then he immediately takes back this claim: “It seems more likely that these consequences would be brought about by other factors.”So…How much does it matter?!