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Habitat Fragmentation Habitat Fragmentation • Community & Ecosystem processes altered Habitat Fragmentation • First-Order Effects: Habitat Fragmentation • Higher-Order Effects: #patches Patch isolation Patch size Edge Implications with Diseases Isolation effects Carnivores & Reserves Area of Reserve (km^2) (A) black bear (F) lion (I) African wild dog (J) grizzly bear Habitat Fragmentation • area-sensitive species: species that require minimum patch size for daily life requirements • Edge effects: Edge Effects 250 m 250 m 31% 64% Total Area = 1 km2 250 m 14% Total Area = 5 km2 Total Area = 0.5 km2 Edge Effects Edge Effects • Habitat surrounding a patch can: - change abiotic conditions; e.g., temp. - change biotic interactions, e.g., predation Habitat Fragmentation: SpeciesSpecific Sensitivity? Habitat Fragmentation: SpeciesSpecific Sensitivity? Swihart et al. 2003. Diversity and Distributions 9:1-8. Differential Sensitivities to Habitat Alteration Swihart et al. 2003