The Community Concept and Ecological Gradients Its a

The Community Concept and Ecological Gradients It’s a diverse planet…

These species interact, in complex ways, with one another- and with the constantly changing environment. And the complexity multiplies…

Community Ecology is science’s attempt to grapple with this complex world. . .

What is an ecological community? ?

Dr. Fredrick Clements: The Community as Superorganism

Dr. Henry Gleason: The individualistic hypothesis of community organization

Vegetation of the Smokey Mountains • R. H. Whittaker (1920 -1980) • Vegetation of the Great Smokey Mountains – (Ecological Monographs 26: 1 -69)

a. Tilia heterophylla; b. Halesia monticola; c. Tsuga canadensis; d. Quercus alba

Which archetypal view of the community does this support?

Edaphic gradient (salinity)

Edaphic gradient (water-logged soil)

Persistent-disturbance gradient Fire

tohee veery

Temporal gradients (long-term) 1) Climate changes constantly 2) This change alters the tolerance vs. competition balance for species. 3) In response, species’ ranges shift- and thus- gradients move in space. 4) This dynamics is unending, what we think of as static (e. g. , maple forests in New England) isn’t.

Margaret Davis: Roger’s Lake Ecology (50: 409 -422), 1969

http: //www. ncdc. noaa. gov/paleo/pollen/viewer/webviewer. html

Shorter-term temporal gradients are successional changes….

Ecological Gradients