Lecture 4 Community Structure II PDF

Assignment 1: Turn in at front of room Lab Week 3: Field trip – meet bus, watch weather. Read ‘Clements v Gleason’ in Lecture 4 Bb folder. Results interp/narration assignment due at beginning of lab. Community Zonation Niche The set of biotic a...

Assignment 1: Turn in at front of room Lab Week 3: Field trip – meet bus, watch weather. Read ‘Clements v Gleason’ in Lecture 4 Bb folder. Results interp/narration assignment due at beginning of lab. Community Zonation Niche The set of biotic and abiotic conditions that a species can tolerate. Communities have distinct or gradual boundaries Ecotone — an abrupt boundary created by sharp changes in environmental conditions over a relatively short distance, accompanied by a major change in the composition of species Ecocline - a gradual, continuous change in the species composition between two communities across an environmental gradient. Whittaker, 1956. Ecological Monographs 26:1-80 The Nature of Communities Frederic Clements Communities are comprised of interdependent organisms Communities are ‘superorganisms,’ ‘holistic’ units Henry Allan Gleason Communities are comprised of independent organisms that respond to environment individualistically Read ‘Clements v Gleason’ in Lecture 4 Bb folder The Nature of Communities Predictions of community-unit vs individualistic perspectives along topo-edaphic gradients Experimental Determination of Study ‘focal species’ – Interdependence (Facilitation) remove neighbors Experimental Determination of Interdependence (Facilitation) Study ‘focal species’ - remove neighbors - monitor for evidence of positive or negative interactions Callaway 2002. Nature 417:844-848