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Donald Winslow, 28 January 2011

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1 Donald Winslow, 28 January 2011
Conservation Biology Donald Winslow, 28 January 2011 Defining conservation biology Valuation of biodiversity Threats to biodiversity Solutions for conservation challenges Sustainability Living in ways that do not degrade resources on which future generations depend, allowing civilization to persist.

2 Defining Conservation Biology
The natural world World ecosystems Biodiversity conservation History of conservation biology

3 Valuation of Biodiversity
Extrinsic values Economic uses of species Medical uses of species Genetic resources Ecosystem services Intrinsic value

4 Threats to biodiversity
Human population growth Human industry and resource use Extinction of species Loss of genetic diversity Habitat change Overexploitation Invasive species & disease Climate change

5 Habitat change Habitat destruction Habitat degradation Fragmentation

6 Habitat destruction Primary cause of biodiversity loss
80+% of threatened species affected by habitat destruction or degradation A decrease in habitat availability decreases the number of breeding territories and thus population productivity.

7 Destruction 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.

8 Habitat fragmentation— loss of contiguity as well as area.

9 Neotropical 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.

10 Wood Thrush (Hylocichla mustelina) incubating

11 Hatching Wood Thrush nest next to regeneration opening

12 Breeding Bird Survey

13 Neotropical migrants are dependent on:
Breeding habitat Migratory stopover sites Winter habitat Therefore, long-distant migrants link the ecosystems of the hemisphere, and They are vulnerable to threats in each of these habitats.

14 Threats 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.

15 Human 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.

16 Brown-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.

17 Brown-headed Cowbirds (Molothrus ater)

18 Nests parasitized by cowbirds

19 Nest 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.

20 Rat snake (Elaphe obsoleta) preying on Wood Thrush (Hylocichla mustelina) nest.

21 Edge Effects on Cowbird Parasitism

22 An “edge” is the border or transition between two habitat types.
Agricultural edges Urban or suburban edges Roads Internal edges from clearcuts or maintained wildlife openings

23 These methods generate high edge density.
Timber is extracted from Indiana state forests using individual and group selection techniques Individual 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.

24 Regeneration opening, Compartment 1, Tract 16

25 Acadian 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.

26 Checking the contents of a Red-eyed Vireo nest.

27 Objective—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.

28 Study Sites Nests 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.

29 Overall Success Rate of
Acadian Flycatcher nests in Yellowwood State Forest before (1995) and after (1996) treatment sites were logged. Treatment:Control 1.22 Treatment:Control 0.563 Ratio of 1996 OSR ratio to 1995 OSR ratio: 0.460, p < (one-tailed)

30 Proportion 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)

31 Possible 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.

32 Lessons from Indiana Where 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.

33 Solutions to conservation challenges
Population level Species level—in situ and ex situ Ecosystem level—protection & restoration Landscape level Regional level Global level Conserving evolutionary processes

34 Sustainability Sustainable practices are practices that can continue indefinitely—without depleting or degrading resources needed to continue. Agriculture Industry Economy Human relations

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