Announcements HW Addendum for CONS670 Reading assignment for BSCI363

pop “a” pop “b” pop “e” pop “g” pop “c” pop “d” pop “f”pop “h” TIME Population Density (Ln) Mean r = 0, P(extinction) = ?

General Predictors of Extinction Population Growth + - Population Size Current population size

General Predictors of Extinction Carrying capacity / population size. Maximum growth rate. Variation in growth rate –Demographic stochasticity –Environmental stochasticity –Genetic stochasticity

Variation in B&D: Demographic Stochasticity “Transparent” in VORTEX Probabilistic nature of births and deaths, males and females Function of –Birth and death rates Fecundity = 0.34? –Sex ratio

Variation in B&D: Demographic Stochasticity Monogamy1 male1 female Polyandry> 1 male1 female Polygyny1 male> 1 female Polygynandry> 1 male> 1 female Polygamy“random breeding”

Variation in B&D: EV Fecundity of adult spotted owls = 0.34 In a “normal” year: 34% of adult females have 1 female offspring. In a “bad” year, EV results in decreased r: e.g., births = 34% - “x” In a “good” year, EV results in increased r: e.g., births = 34% + “x”

frequency X= 34% % of females producing offspring Yearly Variation in Fecundity s.d. ~68% ~95% s.d.

AB 1 YearFecundity (%) SD= STDEV(b2:b6) Calculating S.D. from Data (> 5 yrs.)

ABC 1 Yearbxbx (34-24)^ (34-34)^ (34-14)^ (34-44)^ (34-54)^2 Sqrt(Sum(c2:c6)/(5-1)) Calculating S.D. from Data (> 5 yrs.)

Calculating S.D. From Data (Range) Average fecundity =.34 (range.14 –.54) Calculate S.D., based on years / data points For N ~ 10, assume range defines +/- 1.5 SD. For N ~ 25, assume range defines +/- 2SD For N ~ 50, assume range defines +/ SD For N ~ 100, assume range defines +/- 2.5 SD For N ~ 200, assume range defines +/ SD For N ~ 300, assume range defines +/- 3 SD

“Last Ditch” Estimate of S.D. Where mean value (e.g. fecundity) = 34% “highly tolerant of EV” –let SD = 34%*.05 “very vulnerable to EV” –let SD = 34%*.50 “intermediate tolerance” –let SD = 34%*.25

Variation in B&D: Catastrophes Defined by VORTEX as episodic effects that occasionally depress survival or reproduction. Types (up to 25, start with 1) Independent causes of mass mortality. Probability based on data (# per 100 years). Loss due to catastrophe (= % surviving) 0 = no survivors. 1 = no effect.

Catastrophes: Harbor Seals Disease outbreaks in 1931, 1957, 1964, and : 445 seals out of ~10,000 died. “Few” seals reproduce J. R. Geraci et al., Science 215, (1982).

Catastrophes: Harbor Seals Disease outbreaks in 1931, 1957, 1964, and seals out of ~10,000 died. “Few” seals reproduce Probability of catastrophe: –26, 12, 14 years between outbreaks –Average time between outbreaks = 17 years. –1 every 17 years or 6 every 100 years. Loss (e.g., % surviving) –9,555 / 10,000 ~ 95% –Reproduction = ? J. R. Geraci et al., Science 215, (1982).

Catastrophes: More Info Mangel, M., and C. Tier Four facts every conservation biologist should know about persistence. Ecology 75: –General background Young, T. P Natural die-offs of large mammals: implications for conservation. Conservation Biology 8: –Possible reference or starting point for term-paper Access through JSTOR (

Aa x Where a is deleterious Homozygous recessive is lethal (Recessive Allele Model) Variation in B&D: Genetic Stochasticity Aa AAAAa a aa Presence of “a” allele decreases fitness Reduced fitness = sum of lethal equivalents (Heterosis Model)