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23 Biodiversity • • • • • • • Outline Concepts & definitions Diversity Measures Community Membership Niche Patterns Equilibrium Approach Biodiversity • Ricklefs • A measure of the variety of organisms within a local area or region, often including genetic variation, taxonomic uniqueness, and endemism. Biodiversity Latitudinal Patterns - Fig. 23.1 • Genetic Variation; Fig. 16.5, 16.6 • Latitudinal Patterns - Fig. 23.2 Diversity Measures • Mammals • Regional (gamma) - across habitats • Local (alpha) - within a habitat • Beta - species turnover – New species between habitats 1 Diversity Measures Community Membership? • Beta • Why these species and not others? • Outcome vs. process • Weiher & Keddy – # habitats/mean habitats per species – 10/10 = 1 – 10/5.0 = 2 – 10/2.5 = 4 – 10/1.0 = 10 – specialization – 20 species – Microcosms; water depth, litter, fertility – 5 years Community Membership? Community Membership? • Fig. 23.7 • Fig. 23.7 Year Community Membership? Community Concept - Niche • Fig. 23.8 • Ricklefs • The ecological role of a species in the community. • The range of many conditions and resource qualities within which the organism persists. 2 Fundamental Niche Gause • Competitive exclusion principle – Two species cannot coexist on the same limiting resource. Resource Gradient Realized Niche Fundamental Niche Ecological Time Resource Gradient Realized Niche Resource Partitioning Calcium • Species Packing • Fig. 23.10 Ricklefs 1979 Organic Matter 3 Resource Partitioning Niche Diversity Evidence Fig. 23.11 • Species diversity corresponds to niche diversity • Niche Diversity Evidence Fig. 23.11 Diversity-Abundance Trade-off • http://pixdaus.com/?sort=tag&tag=bat • Productivity limits? • Fig. 23.9 http://www.britannica.com/EBchecked/topic-art/55655/19477/Epauletted-fruit-bat-feeding-onwild-figs Diversity-Abundance Trade-off Diversity-Abundance Trade-off • Ecological release • Lower species richness (islands) • Ecological release? • Predation lowers abundance – Shift & broaden niches Resource Gradient Resource Gradient 4 Patterns and Causes Hypothesis • Latitude • Fig. 23.2 • Physical – Temperature – Water Smith & Smith 2001 Hypothesis Hypothesis • Physical • Productivity; Fig 23.6 – Temperature – Water Smith & Smith 2001 Hypothesis Hypothesis • Productivity & Habitat Heterogeneity • Fig 23.3 • Heterogeneity Smith & Smith 2001 5 • Heterogeneity - Fig 23.5 Breeding Birds Hypothesis P = 0.02 Shrub Cover Hypothesis Hypothesis • Dispersal • Dispersal Smith & Smith 2001 Smith & Smith 2001 Patterns and Causes Hypothesis • Predation & Herbivory • Disturbance Smith & Smith 2001 Bush 2002 6 Patterns and Causes Equilibrium • Predation & Herbivory; Fig 23.21 • New Approach – Islands – Continental Island Biogeography Island Biogeography • Robert MacArthur (1930-1972) • Edward O. Wilson • Fig 23.14 faculty-staff.ou.edu/.../associates.htm ham.muohio.edu/news/2006/eo_wilson.htm pupress.princeton.edu/titles/7051.html Island Biogeography Island Biogeography • Fig 23.15 • 7 Island Biogeography Island Biogeography • Fig 23.15 • Fig 23.16 Small S Island Biogeography; test; Fig 23.17 Island Biogeography; test; Fig 23.18 • • Dan Simberloff userwww.sfsu.edu/~gscb/speakers.htm Continental Equilibria Fig 23.19 Tuesday • Immigration & Speciation • Chapter 24 8
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