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Group Territoriality, Dispersal and Population Persistence in an Endangered Species

Group Territoriality, Dispersal and Population Persistence in an Endangered Species. Endangerment Loss of Required/Preferred Habitat Habitat Fragmentation Habitat Degradation Number of Territories Dispersal Distance Between Territories. Red-Cockaded Woodpecker. Picoides borealis.

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Group Territoriality, Dispersal and Population Persistence in an Endangered Species

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  1. Group Territoriality, Dispersal and Population Persistence in an Endangered Species Endangerment • Loss of Required/Preferred Habitat • Habitat Fragmentation • Habitat Degradation Number of Territories Dispersal Distance Between Territories

  2. Red-Cockaded Woodpecker Picoides borealis Endangered 1985 - USFWS Group Territoriality Cooperative Breeding Male Helpers

  3. Red-Cockaded Woodpecker Excavate Nesting Cavity 80+ Year-Old Pine, Heartwood Endemic Mature Pine Forests, Southeast

  4. Extinction: Causes • Demographic Stochasticity Among-Individual Variation 2. Environmental Stochasticity Among-Generation Variation 3. Catastrophe 4. Inadequate Genetic Variation

  5. Avoid Extinction: Viable Population Commonly Large Enough to Withstand Demographic and Environmental Stochasticity Catastrophe Difficult to Plan Red-cockaded Woodpecker USFWS: Large Enough to Avoid Loss Alleles Thru Genetic Drift

  6. Red-Cockaded Woodpecker Recovery Plan • Preserve Breeding Habitat and Establish New Populations • Maintain Viable Local Populations Challenges • Habitat Loss (Fewer Territories) • Fragmentation (Greater Dispersal Distance)

  7. Red-Cockaded Woodpecker Letcher, Priddy, Walters & Crowder (1998) Biol. Conservation 86:1 – 14. • Between-Sex Behavioral Differences in Dispersal • Territory Availability • Spatial Aggregation of Territories “Clumped”  Reduced Dispersal Distance

  8. Letcher, Priddy, Walters & Crowder (1998)Biol. Conservation 86:1 – 14. Territories “fixed” by availability of old trees Breeding pair and non-breeding helpers Competition for breeding status/territory Female fledglings disperse, long distance Male fledglings remain as helpers Breed on natal territory Disperse, short distance

  9. Female Life History: Disperse to Breed

  10. Male Life History: Most help before breeding

  11. Letcher, Priddy, Walters & Crowder (1998)Biol. Conservation 86:1 – 14. J. Walters: 25 yrs.; behavior and life histories > 200 groups in North Carolina > 2000 individuals Data to parameterize demography/conservation model Territory number (habitat loss) Spatial pattern (dispersal distances)

  12. Letcher, Priddy, Walters & Crowder (1998)Biol. Conservation 86:1 – 14.

  13. Letcher, Priddy, Walters & Crowder (1998)Biol. Conservation 86:1 – 14.

  14. Letcher, Priddy, Walters & Crowder (1998)Biol. Conservation 86:1 – 14.

  15. Letcher, Priddy, Walters & Crowder (1998)Biol. Conservation 86:1 – 14. Population Persistence Clutch size (obvious) Female Dispersal (Long Distance) Avoid Mortality, Find Breeding Opportunity Number of Territories Male Dispersal (Short Distance) Find/Compete Breeding Opportunity Spatial Aggregation of Territories

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