Community Ecology
Spatial dynamics of communities: terrestrial analogs of IB

Click here for supplemental materials for today (PDF)

Outline:

1. Goal of many ecologists is preservation of biodiversity against extinction

A. Four main causes of extinction (Shaffer 1981)

i. genetic

ii. demographic stochasticity

iii. environmental stochasticity

iv. deterministic causes

a. fragmentation

3. Reserve design

A. Corridors and connectivity

i. pros and cons of corridors

4. Metapopulations

Terms/people:

extinction (and its 4 causes) fragmentation

connectivity rescue effect (Brown & Kodric-Brown)

edge effects corridor

metapopulation (Levins 1969)

source-sink (Pulliam 1988)

A primary goal of many ecologists is preservation of biodiversity against extinction. Extinction arises through (Shaffer 1981):
-genetic causes -
-demographic stochasticity -
-environmental stochasticity -
-deterministic causes (e.g. fragmentation) -

(Be able to provide examples of each of the above.)

fragmentation à habitat loss and isolation

To combat negative effects from fragmentation: reserve design
-recall Diamond’s "design principles" (and Simberloff’s criticisms of them).

-corridors and connectivity (Figs. 12.1-12.2 in Mittelbach text)

benefits and costs

metapopulation biology

types: see Figs. 12.3-12.5 in Mittelbach text

special type: source-sink metapopulations (Pulliam 1988)

Next time: applied community ecology and future directions in community ecology

References:

Ahern, J. 1999. Spatial concepts, planning strategies, and future scenarios: A framework method for integrating landscape ecology and landscape planning. Pp. 175-201 in: Landscape Ecological Analysis: Issues and Applications (J.M. Klopatek and R.H. Gardner, eds.). Springer-Verlag, New York, NY.

Andreassen, H.P., S. Halle, and R.A. Ims. 1996. Optimal width of movement corridors for root voles: not too narrow and not too wide. J. Appl. Ecol. 33:63-70.

Andreassen, H.P., R.A. Ims, and O.K. Steinset. 1996. Discontinuous habitat corridors: effects on male root vole movements. J. Appl. Ecol. 33:555-560.

Arnold, G.W. 1995. Incorporating landscape pattern into conservation programs. Pp. 309-337 in: Mosaic Landscapes and Ecological Processes (L. Hansson, L. Fahrig, and G. Merriam, eds.). Chapman and Hall, London, UK.

Bissonette, J.A. 1997. Wildlife and Landscape Ecology: Effects of Pattern and Scale. Springer-Verlag, New York, NY.

Brown, J.H., and A. Kodric-Brown. 1977. Turnover rates in insular biogeography: effect of immigration on extinction. Ecology 58:445-449.

Cabeza, M., and A. Moilanen. 2001. Design of reserve networks and the persistence of biodiversity. Trends Ecol. Evol. 16:242-248.

Conroy, M.J., and B.R. Noon. 1996. Mapping of species richness for conservation of biological diversity: conceptual and methodological issues. Ecol. Appl. 6:763-775.

Hobbs, R.J. 1992. The role of corridors in conservation: solution or bandwagon? Trends Ecol. Evol. 7:389-392.

Levins, R. 1969. Some demographic and genetic consequences of environmental heterogeneity for biological control. Bull. Entomol. Soc. Am. 15:237-240.

Lindenmayer, D.B., and M.A. Nix. 1993. Ecological principles for the design of wildlife corridors. Conserv. Biol. 7:627-630.

Noss, R.F. 1987. Corridors in real landscapes: a reply to Simberloff and Cox. Conserv. Biol. 1:159-164.

Prendergast, J.R., R.M. Quinn, and J.H. Lawton. 1999. The gaps between theory and practice in selecting nature reserves. Conserv. Biol. 13:484-492.

Pressey, R.L., and R.M. Cowling. 2001. Reserve selection algorithms and the real world. Conserv. Biol. 15:275-277.

Pulliam, H.R. 1988. Sources, sinks, and population regulation. Am. Nat. 132:652-661.

Schreiber, S.J., and M. Kelton. 2005. Sink habitats can alter ecological outcomes for competing species. J. Anim. Ecol. 74:995-1004.

Shaffer, M.L. 1981. Minimum population sizes for species conservation. BioScience 31:131-134.

Simberloff, D., and J. Cox. 1987. Consequences and costs of conservation corridors. Conserv. Biol. 1:63-71.

Simberloff, D., J.A. Farr, J. Cox, and D.W. Mehlman. 1992. Movement corridors: conservation bargains or poor investments? Conserv. Biol. 6:493-504.