Presentation on theme: "Donald Winslow, 28 January 2011"— Presentation transcript:
1Donald Winslow, 28 January 2011 Conservation BiologyDonald Winslow, 28 January 2011Defining conservation biologyValuation of biodiversityThreats to biodiversitySolutions for conservation challengesSustainabilityLiving in ways that do not degrade resources on which future generations depend, allowing civilization to persist.
2Defining Conservation Biology The natural worldWorld ecosystemsBiodiversity conservationHistory of conservation biology
3Valuation of Biodiversity Extrinsic valuesEconomic uses of speciesMedical uses of speciesGenetic resourcesEcosystem servicesIntrinsic value
4Threats to biodiversity Human population growthHuman industry and resource useExtinction of speciesLoss of genetic diversityHabitat changeOverexploitationInvasive species & diseaseClimate change
6Habitat destruction Primary cause of biodiversity loss 80+% of threatened species affected by habitat destruction or degradationA decrease in habitat availability decreases the number of breeding territories and thus population productivity.
7Destruction vs. degradation Destruction: Changed to such an extent that one or more ecological populations can no longer use the habitat.Degradation: Habitat still used, but individuals have lower fitness and populations reduced viability.
8Habitat fragmentation— loss of contiguity as well as area.
9Neotropical Migrant Birds Winter in tropics in Central and South America.Breed in temperate North America during the spring & summer.Long-term continental declines have been observed in a number of species.
13Neotropical migrants are dependent on: Breeding habitatMigratory stopover sitesWinter habitatTherefore, long-distant migrants link the ecosystems of the hemisphere, andThey are vulnerable to threats in each of these habitats.
14Threats on breeding grounds: Habitat destruction.Habitat degradation.Habitat fragmentation.Brood parasitism by Brown-headed Cowbirds (Molothrus ater).Nest predation by various nest predators.Agricultural pesticides reduce food availability and poison birds.
15Human land-use patterns affect the abundance, distribution, & activity of cowbirds & nest predators Cowbirds feed in pastures, agricultural fields and lawns.Cowbirds and many nest predators(e.g. Blue Jays, rat snakes, and raccoons) use forest edges.
16Brown-headed Cowbirds (Molothrus ater) Do not build their own nests.Lay their eggs in the nests of other birds.Often remove a host egg from the nest.The host parents raise the cowbird young.Cowbird nestlings out-compete host young and sometimes push them from the nest.
19Nest predators in Midwestern forests include: Blue Jays and crows.Snakes, such as the black rat snake.Large mammals, such as racoons and skunks.Small mammals, such as squirrels and mice.Many other birds and mammals may harm eggs and nestlings if given a chance.
22An “edge” is the border or transition between two habitat types. Agricultural edgesUrban or suburban edgesRoadsInternal edges from clearcuts or maintained wildlife openings
23These methods generate high edge density. Timber is extracted from Indiana state forests using individual and group selection techniquesIndividual selection—Individual trees are removed from within a harvest tract.Group selection—Small openings are created by removing groups of trees.Site preparation entails the construction and maintenance of roads, skid trails, and log landings.These methods generate high edge density.
25Acadian Flycatcher (Empidonax virescens) Breeds in eastern United States.Winters in Central and South America.Nests in mature forest, May-August.Nest suspended from fork in branch, typically 3- 7 m high.Clutch size usually 3.Female incubates.Both parents feed young.
27Objective—Experimentally evaluate the effects of logging in Yellowwood State Forest on nest survival and cowbird parasitism level.Hypothesis—Timber extraction decreases nest survival (by increasing predation) and increases parasitism.Prediction—Nest survival will be lower and parasitism higher after logging than before, relative to values measured in unlogged sites.
28Study SitesNests in eight tracts in Yellowwood State Forest were monitored in 1995 & (Three were also monitored in 1994.)Four sites were logged between 1995 &The other four sites were close to rotation age but remained unlogged during 1996.
29Overall Success Rate of Acadian Flycatcher nests in Yellowwood State Forestbefore (1995) and after (1996) treatment sites were logged.Treatment:Control 1.22Treatment:Control 0.563Ratio of 1996 OSR ratio to 1995 OSR ratio: 0.460, p < (one-tailed)
30Proportion of Acadian Flycatcher nests parasitized before (1995) and after (1996) treatment sites were logged.Interaction effect: G = 3.49, df = 1, p = 0.031, (one-tailed)
31Possible interpretations If factors responsible for between-year variation operate similarly in both sets of sites, the observed interactions between year and treatment may indicate logging decreases breeding success.Alternatively, site-specific processes at control tracts may have caused higher success in 1996.
32Lessons from IndianaWhere avian conservation is a priority in eastern deciduous forests, timber extraction should be limited until effects on nesting success are understood.Special attention should be given to monitoring breeding success of bird species that preferentially select edge habitats.
33Solutions to conservation challenges Population levelSpecies level—in situ and ex situEcosystem level—protection & restorationLandscape levelRegional levelGlobal levelConserving evolutionary processes
34SustainabilitySustainable practices are practices that can continue indefinitely—without depleting or degrading resources needed to continue.AgricultureIndustryEconomyHuman relations