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Published byRandolph Darren Norton Modified over 9 years ago
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A Curlew’s Farewell I tried but I can try no more I cried but I can cry no more I failed to bring a young chick’s cry into this world Time now bids me say farewell The sun is setting and I must go But I will come again next year… and try Until I die. J.N. Allen (U.S Fish & Wildlife Service)
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Wildlife Reproduction So many definitions! What affects wildlife reproduction? How does reproduction affect population dynamics? How do mating habits affect productivity? How does understanding reproductive physiology & behavior help me as a biologist? Who cares?
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Wildlife Reproduction Females only? (U.S Fish & Wildlife Service)
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Wildlife Reproduction Fecundity Fertility Natality Recruitment* –Rate b = ind./ind.*time –Management Implications
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Wildlife Reproduction Productivity –Recruitment –Surplus or yield produced –# offspring surviving –dN/dt* Biotic Potential Population Size Time ABC
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Wildlife Reproduction Sex Relations/Mating Habits –Monogamy –Polygamy Polyandry Polygyny Promiscuity –Management Implications (U.S Fish & Wildlife Service)
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Wildlife Reproduction Sex Ratios –% males:% females 36:64 –# males/# females 1 buck/2 does –# males/100 females 2 males/100 females
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Wildlife Reproduction Sex Ratios –Primary Fertilization –50:50 –Secondary Birth –~50:50 –Tertiary Juveniles –Quarternary Adults (Recruited) (U.S Fish & Wildlife Service)
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Wildlife Reproduction Sex Ratios –Influences Mortality/decimating factors –Harvest, weather, disease, etc… –Mating habits Monogamous Polygynous Polyandrous
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Wildlife Reproduction Effects of Age –Management Implications? Age Reproductive Value (V x ) Mammals & Birds Herps & Fish
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Wildlife Reproduction Factors Influencing Annual Reproductive Success Onset & length of breeding season Litter/clutch size Prenatal survival Survival of newborns Parental care Age at sexual maturity Sex ratios & mating habits Population density
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Wildlife Reproduction Factors Influencing Annual Reproductive Success Onset & length of breeding season –Environmental factors & implications Biological clocks Timing: conditions, fertilization, & satiation JanMarMayJulSepNov Northern Bobwhite HatchingSeverest Conditions Covey Breakup & PairingCovey Formation Hunting SeasonEgg Laying
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Wildlife Reproduction Factors Influencing Annual Reproductive Success Litter/clutch size –Environmental factors & implications Age Region Timing/season Nutrition –Manageable NOAA Photo
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Wildlife Reproduction Factors Influencing Annual Reproductive Success Prenatal survival –Gestation & incubation Fertility v. natality –Environmental factors & implications Nutrition & habitat –Sex ratios (e.g., deer) Manageable
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Wildlife Reproduction Factors Influencing Annual Reproductive Success Survival of newborns* –Environmental factors & implications Nutrition & habitat Manageable Northern Bobwhite Ruffed Grouse
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Wildlife Reproduction Factors Influencing Annual Reproductive Success Parental care –Environmental factors & implications Parental Effort Survival Rate Parental Offspring
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Wildlife Reproduction Factors Influencing Annual Reproductive Success Age at sexual maturity* –Environmental factors & management implications Morton and Cheatum (1946) Northern NY –Overbrowsed, poor soil, & deep snow –4 % of fawns pregnant Southern NY –Adequate forage, better soil, & less snow –36 % of fawns pregnant (U.S Fish & Wildlife Service)
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Wildlife Reproduction Factors Influencing Annual Reproductive Success 100 juv F 1 st breed at age 3 (Ad) 1 juv F/age 3+ F/yr –Yr 0: 100 –Yr 1: 100 –Yr 2: 100 –Yr 3: 100 –Yr 4: 200 –Yr 5: 300 –Yr 6: 400 –Yr 7: 500 –Yr 8: 700 100 juv F 1 st breed at age 2 (Ad) 1 juv F/age 2+ F/yr –Yr 0: 100 –Yr 1: 100 –Yr 2: 100 –Yr 3: 200 –Yr 4: 300 –Yr 5: 400 –Yr 6: 600 –Yr 7: 900 –Yr 8: 1300 Age at sexual maturity = delaying recruitment + twinning effects Manageable
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Wildlife Reproduction Factors Influencing Annual Reproductive Success Population structure –2 ◦ factors (population ecology) –Age or population pyramid 8 9 7 5 6 4 3 2 1 Age Class Male FemaleMale FemaleMale Female
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Wildlife Reproduction Factors Influencing Annual Reproductive Success Sex ratios & mating habits –Monogamous Environmental factors & management implications Sex RatioMax. # nests/100 birds 50:5050 75:2525 25:7525
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Wildlife Reproduction Factors Influencing Annual Reproductive Success Sex ratios & mating habits –Polygynous Environmental factors & management implications Sex RatioMax. # nests/100 birds 50:5050 75:2525 25:7525-75
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Wildlife Reproduction Factors Influencing Annual Reproductive Success Sex ratios & mating habits –Polyandrous Environmental factors & implications Sex RatioMax. # nests/100 birds 50:5050 75:2525 25:7525
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Wildlife Reproduction Factors Influencing Annual Reproductive Success Population density –Many welfare & decimating factors –Density-dependence Population Density Reproductive Rate A B
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Wildlife Reproduction Factors Influencing Annual Reproductive Success Population density –Density-dependence & habitat Population Density Reproductive Rate A BC Allee Effect
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Wildlife Reproduction Reproductive & Courtship Behavior –Mate attraction –Intraspecific recognition –Stimulate & synchronize copulation (U.S Fish & Wildlife Service) Trade-offs Evolved with certain conditions Habitats & management
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Wildlife Reproduction Courtship Behavior –Management implications Survival & sex ratios –Many birds & ungulates –Lekking spp. (U.S Fish & Wildlife Service) (Forestryimages)
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Wildlife Reproduction Courtship Behavior –Management implications Sage grouse - Lek ♀ ♂ ♂ ♂ ♂ ♂ ♂ ♂ ♂ ♂ ♂ ♂ ♂ ♂ (Forestryimages) ♀ ♀♀ ♀ ♀ ♀ ♀ ♀ ♀ ♀ ♀ ♀ ♂ ♀
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Wildlife Reproduction Courtship Behavior –Management implications Sampling (U.S Fish & Wildlife Service)
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Wildlife Reproduction Reproductive Physiology & Behavior –Biological clocks –Implications Brain & Endocrine System Other animals Photoperiod* Other resources Water Climate/weather Cover Food Mating behavior Social behavior Molt/shed Migration Dispersal Fat deposition Gonad development Space
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Wildlife Reproduction Reproductive Physiology & Behavior –Implications Space as a Welfare Factor –Crowding, disturbance, & other stressors –General adaptation syndrome (GAS) or non-specific stress response Stressor Pituitary Gland ACTHAdrenal Cortex Corticoid Hormones Growth Water Balance Glucose Metabolism Disease Resistance Development of Sex Organs and Behavior Other
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Wildlife Reproduction Imprinting –Permanent learning during the critical period –Implications (U.S Fish & Wildlife Service)
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Wildlife Reproduction Who cares?
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