Community Ecology
Spatial dynamics of communities: landscape ecology

Outline:

1. Patch-matrix approach to organism-environment interactions

A. Assumptions of P-M

B. Problems with P-M

2. Alternative to P-M: mosaic approach

A. Focus is on amount, placement, and connectivity of landscape elements

B. Is associated with rise of landscape ecology

3. Landscape ecology

A. Scope/focus

B. History

i. Europe: origins, foci, key players

ii. North America: differences to European school, foci, key players

4. Importance of considering landscape mosaic structure in community ecology

Terms/people:

patch-matrix approach mosaic approach landscape ecology

Carl Troll European vs. North American schools of thought

amount, placement, connectivity of landscape elements

"...spatial variability, or patchiness, in natural populations is a dynamically interesting quantity rather than a statistical nuisance to be overcome..." (Schneider 1994, p. 7)

patch-matrix approach
terrestrial analog of island biogeography

problems, especially with concept of “sea” (matrix)

Habitat fragmentation and the matrix:

http://www.youtube.com/watch?v=JZwTZ-d1ZRE&desktop_uri=%2Fwatch%3Fv%3DJZwTZ-d1ZRE&app=desktop

The Wog Wog Experiment:

http://vimeo.com/21249067

paradigm shift à mosaic approach

amount, placement, and connectivity of landscape elements (Dunning et al. 1992, Taylor et al. 1993)

This paradigm shift corresponds to the rise of a new field in ecology: landscape ecology ("the study of the effects of pattern on process" - Turner 1989)

Roots in Europe, Carl Troll 1939


The European vs. North American “schools” of landscape ecology

Why considering landscape ecology & spatial effects is important to community ecology:

For much of its history, community ecology has been conducted while tacitly ignoring spatial heterogeneity: predators perfectly mixed with prey, competitors were only affected by the actions of their fellow competitors, niches were constant in space, etc. This is not to say that there weren't a few ecologists who recognized the importance of including spatial variables, but they were definitely in the minority. Yet space is inherent in community ecology:

"...the problem of pattern and scale is the central problem in ecology, unifying population biology and ecosystem science, and marrying basic and applied ecology." (Levin 1992)

Spatial effects on communities:

- species-area relationship

- Huffaker’s (1958) work on the role spatial heterogeneity and refugia play in permitting predator-prey coexistence

- “rescue effect” of Brown and Kodric-Brown (1977)

- “spreading of risk” (den Boer 1968)

- SLOSS

- etc.

Adopting the approaches from landscape ecology will thus make community ecology a more realistic and rigorous science.

Next time: Communities in landscape mosaics and conservation reserve design

References:

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

Davies, K.F., B.A. Melbourne, and C.R. Margules. 2001. Effects of within- and between-patch processes on community dynamics in a fragmentation experiment. Ecology 82:1830-1846.

den Boer, P.J. 1968. Spreading of risk and stabilization of animal numbers. Acta Biotheoretica 18:165-194.

Dunning, J.B, B.J. Danielson, and H.R. Pulliam. 1992. Ecological processes that affect populations in complex landscapes. Oikos 65:169-175.

Forman, R.T.T. 1995. Land Mosaics: The Ecology of Landscapes and Regions. Cambridge University Press, Cambridge, UK.

Forman, R.T.T., and M. Godron. 1986. Landscape Ecology. John Wiley & Sons, New York, NY.

Forys, E., and S.R. Humphrey. 1999. The importance of patch attributes and context to the management and recovery of an endangered lagomorph. Landscape Ecol. 14:177-185.

Hansson, L., L. Fahrig, and G. Merriam, eds. 1995. Mosaic Landscapes and Ecological Processes. Chapman and Hall, London, UK.

Huffaker, C.B. 1958. Experimental studies on predation: dispersion factors and predator-prey oscillations. Hilgardia 27:343-383.

Levin, S.A. 1992. The problem of pattern and scale in ecology. Ecology 73:1943-1967.

Naveh, Z., and A. Lieberman. 1994. Landscape Ecology: Theory and Applications. Springer-Verlag, New York, NY.

Pickett, S.T.A., and M.L. Cadenasso. 1995. Landscape ecology: spatial heterogeneity in ecological systems. Science 269:331-334.

Schneider, D.C. 1994. Quantitative Ecology: Spatial and Temporal Scaling. Academic Press, New York, NY.

Taylor, P.D., L. Fahrig, K. Henein, and G. Merriam. 1993. Connectivity is a vital element of landscape structure. Oikos 68:571-573.

Turner, M.G. 1989. Landscape ecology: the effect of pattern on process. Annu. Rev. Ecol. Syst. 20:171-197.

Urban, D.L., R.V. O’Neill, and H.H. Shugart. 1987. Landscape ecology. BioScience 37:119-127.

Wiens, J.A. 1995. Landscape mosaics and ecological theory. Pp. 1-26 in: Mosaic Landscapes and Ecological Processes (L. Hansson, L. Fahrig, and G. Merriam, eds.). Chapman and Hall, London, UK.

Wiens, J.A, and B.T. Milne. 1989. Scaling of ‘landscapes’ in landscape ecology, or, landscape ecology from a beetle’s perspective. Landscape Ecology 3:87-96.

Wiens, J.A., N.C. Stenseth, B. Van Horne, and R.A. Ims. 1993. Ecological mechanisms and landscape ecology. Oikos 66:369-380.