BIO 373 1st Edition Lecture 21 Outline of Last Lecture I. Communities contda. Changes in communitiesi. Agents of change1. Abiotic2. Bioticii. Succession1. Primary and secondary succession2. Early modes of succession3. Connel and Slatyer’s 3 modes of successiona. Facilitation modelb. Tolerance modelc. Inhibition modelOutline of Current Lecture II. Communities contda. Changes in communities contdi. Chapin experimentii. Mechanism of successioniii. Alternative stable statesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. Fouling communities2. Stability, change, hysteresisIII. Species Diversitya. Spatial scalesi. Global, regional, landscape, localb. Filters i. Importance in invasive speciesc. Models of coexistencei. Resource portioningii. Intermediate disturbance hypothesisiii. Lottery modelCurrent LectureCommunities Contd- Changes in communities contdo Succession Chapin Experiment- Tested 3 models of succession at Glacier Bay- Observed seedling survival and germination rate at succession stageso Pioneer, Dryas, Alder, and Spruceo Determined dominate species and succession Mechanism of succession- Facilitative interactions are often important drivers of early successiono Especially when physically conditions are stressfulo Larger, slower growing, long-lived species begin to dominate as succession progresseso Competition plays a larger role later in successiono Alternative stable states =different communities develop in the same area under similar environmental conditions Stable= when community returns to original state after perturbation Fouling communities and alternative states- Agent of change was predation here- Determined dominate species Stability—community in original state Change—community may enter another stable state Hysteresis—reversal of change but no return to original conditions because original shift was large and reversal was not large enoughSpecies Diversity- Landscape= patchwork of communities- Interconnected spatial scales of species diversityo Global regional landscape localo Regional makes up global, landscapes make up region, local communities make up landscapes- Series of filters that bring species into a communitieso Filters determine community membershipo Dispersal of immigration (regional) abiotic factors (what can a species withstand)species interaction (local)o Importance of filters in invasive species Dispersal—who makes it down to next filter and who leaves Abiotic factors—can other species withstand these conditions- Important in removing invasive species- who can withstand negative effects filters control if a species can become invasive or not- will native species allow invasive species to become part of community- models of coexistenceo resource partitioning, Intermediate disturbance hypothesis, lottery model Resource partitioning—theory by McArthur- McArthur studied migratory birds during reproductive season and observed resource partitioning of nest size and feeding location- To coexist must use resources in different ways- Prevents dominance- Species resource use falls on spectrumo Ex: some eat larger size of prey, some eat intermediate size, some eat small o Species can specialize in resource use with character displacement, evolution,