Applications of Markov chains in demography and population

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Applications of Markov chains in demography and population ecology Hal Caswell Biology Department Woods

Applications of Markov chains in demography and population ecology Hal Caswell Biology Department Woods Hole Oceanographic Institution Copyright 2006 Hal Caswell

Markov chains in demography • • particle = individual organism states = stages in

Markov chains in demography • • particle = individual organism states = stages in the life cycle chains absorbing questions relate to absorbtion – where – timing – perturbation analysis June 2006 Hal Caswell -- Markov Anniversary Meeting 2

 • Patterns and rates of transition reflect hypotheses about biological processes – growth

• Patterns and rates of transition reflect hypotheses about biological processes – growth – development – maturation – reproduction – mortality June 2006 Hal Caswell -- Markov Anniversary Meeting 3

Discrete demography • • • life cycle stages projection interval transitions reproduction June 2006

Discrete demography • • • life cycle stages projection interval transitions reproduction June 2006 Hal Caswell -- Markov Anniversary Meeting 4

Age-classified life cycle June 2006 Hal Caswell -- Markov Anniversary Meeting 5

Age-classified life cycle June 2006 Hal Caswell -- Markov Anniversary Meeting 5

Size-classified life cycles Teasel (Dipsacus sylvestris) 1. 2. 3. 4. 5. 6. June 2006

Size-classified life cycles Teasel (Dipsacus sylvestris) 1. 2. 3. 4. 5. 6. June 2006 Hal Caswell -- Markov Anniversary Meeting Dormant seeds 1 Dormant seeds 2 Small rosettes Medium rosettes Large rosettes Flowering plants 6

Stage-classified life cycles Wandering albatross (Diomedea exulans) June 2006 Hal Caswell -- Markov Anniversary

Stage-classified life cycles Wandering albatross (Diomedea exulans) June 2006 Hal Caswell -- Markov Anniversary Meeting extracted from Croxall et al. 71990

North Atlantic right whale calf June 2006 immature Hal Caswell -- Markov Anniversary Meeting

North Atlantic right whale calf June 2006 immature Hal Caswell -- Markov Anniversary Meeting mom post-mom 8

June 2006 Hal Caswell -- Markov Anniversary Meeting 9

June 2006 Hal Caswell -- Markov Anniversary Meeting 9

June 2006 Hal Caswell -- Markov Anniversary Meeting 10

June 2006 Hal Caswell -- Markov Anniversary Meeting 10

Analysis within the life cycle • partition entries into transitions and reproduction • recognize

Analysis within the life cycle • partition entries into transitions and reproduction • recognize that death is present as an absorbing state • life cycle describes dynamics on transient states of an absorbing Markov chain June 2006 Hal Caswell -- Markov Anniversary Meeting 11

June 2006 Hal Caswell -- Markov Anniversary Meeting 12

June 2006 Hal Caswell -- Markov Anniversary Meeting 12

reproduction rates (s x s) transition probabilities (s x s) mortality probabilities (1 x

reproduction rates (s x s) transition probabilities (s x s) mortality probabilities (1 x s) absorbtion probabilities (a x s) June 2006 Hal Caswell -- Markov Anniversary Meeting 13

1=calf 2=immature 3=mature 4=mom 5=post-mom 6=dead June 2006 Hal Caswell -- Markov Anniversary Meeting

1=calf 2=immature 3=mature 4=mom 5=post-mom 6=dead June 2006 Hal Caswell -- Markov Anniversary Meeting 14

Importance? • population dynamics • conservation (growth and persistence, invasion and recolonization) • evolution

Importance? • population dynamics • conservation (growth and persistence, invasion and recolonization) • evolution (success of life cycles, aging, environmental response) June 2006 Hal Caswell -- Markov Anniversary Meeting 15

June 2006 Hal Caswell -- Markov Anniversary Meeting 16

June 2006 Hal Caswell -- Markov Anniversary Meeting 16

June 2006 Hal Caswell -- Markov Magnus and Neudecker 1988, Nel 1980 Anniversary Meeting

June 2006 Hal Caswell -- Markov Magnus and Neudecker 1988, Nel 1980 Anniversary Meeting 17

hours of fun for everybody! June 2006 Hal Caswell -- Markov Anniversary Meeting 18

hours of fun for everybody! June 2006 Hal Caswell -- Markov Anniversary Meeting 18

The North Atlantic right whale (Eubalaena glacialis) June 2006 Hal Caswell -- Markov Anniversary

The North Atlantic right whale (Eubalaena glacialis) June 2006 Hal Caswell -- Markov Anniversary Meeting 19

Endangered, by any standard N < 300 individuals feeding Minimal recovery since 1935 Ship

Endangered, by any standard N < 300 individuals feeding Minimal recovery since 1935 Ship strikes calving June 2006 Hal Caswell -- Markov Anniversary Meeting Entanglement with fishing gear 20

Mortality and serious injury due to entanglement and ship strikes 2030: died October 1999

Mortality and serious injury due to entanglement and ship strikes 2030: died October 1999 entanglement June 2006 1014 “Staccato” died April 1999 ship strike Hal Caswell -- Markov Anniversary Meeting 21

1=calf 2=immature 3=mature 4=mom 5=post-mom 6=dead June 2006 Hal Caswell -- Markov Anniversary Meeting

1=calf 2=immature 3=mature 4=mom 5=post-mom 6=dead June 2006 Hal Caswell -- Markov Anniversary Meeting 22

Parameter estimation • photographic ID catalog • multistage markrecapture analysis • maximum likelihood estimates

Parameter estimation • photographic ID catalog • multistage markrecapture analysis • maximum likelihood estimates June 2006 Hal Caswell -- Markov Anniversary Meeting 23

Results • data 1980 -1998 • series of statistical models • evidence for declining

Results • data 1980 -1998 • series of statistical models • evidence for declining trend in survival of moms, and of birth rate • population growth rate declined to negative levels Fujiwara and Caswell 2001 Caswell and Fujiwara 2004 June 2006 Hal Caswell -- Markov Anniversary Meeting 24

Time-invariant model June 2006 Hal Caswell -- Markov Anniversary Meeting 25

Time-invariant model June 2006 Hal Caswell -- Markov Anniversary Meeting 25

June 2006 Hal Caswell -- Markov Anniversary Meeting 26

June 2006 Hal Caswell -- Markov Anniversary Meeting 26

E(number of reproductive events) June 2006 Hal Caswell -- Markov Anniversary Meeting 27

E(number of reproductive events) June 2006 Hal Caswell -- Markov Anniversary Meeting 27

Right whale calf 18 16 Expected occupancy (yrs) 14 12 10 8 6 4

Right whale calf 18 16 Expected occupancy (yrs) 14 12 10 8 6 4 2 0 June 2006 calf imm mature Hal Caswell -- Markov Anniversary Meeting mom post-mom 28

June 2006 Hal Caswell -- Markov Anniversary Meeting 29

June 2006 Hal Caswell -- Markov Anniversary Meeting 29

June 2006 Hal Caswell -- Markov Anniversary Meeting 30

June 2006 Hal Caswell -- Markov Anniversary Meeting 30

June 2006 Hal Caswell -- Markov Anniversary Meeting 31

June 2006 Hal Caswell -- Markov Anniversary Meeting 31

Right whale calf CV of stage occupancy time 1. 5 1 0. 5 0

Right whale calf CV of stage occupancy time 1. 5 1 0. 5 0 June 2006 calf imm mature Hal Caswell -- Markov Anniversary Meeting mom post-mom 32

June 2006 Hal Caswell -- Markov Anniversary Meeting 33

June 2006 Hal Caswell -- Markov Anniversary Meeting 33

June 2006 Hal Caswell -- Markov Anniversary Meeting 34

June 2006 Hal Caswell -- Markov Anniversary Meeting 34

June 2006 Hal Caswell -- Markov Anniversary Meeting 35

June 2006 Hal Caswell -- Markov Anniversary Meeting 35

June 2006 Hal Caswell -- Markov Anniversary Meeting 36

June 2006 Hal Caswell -- Markov Anniversary Meeting 36

June 2006 Hal Caswell -- Markov Anniversary Meeting 37

June 2006 Hal Caswell -- Markov Anniversary Meeting 37

June 2006 Hal Caswell -- Markov Anniversary Meeting 38

June 2006 Hal Caswell -- Markov Anniversary Meeting 38

June 2006 Hal Caswell -- Markov Anniversary Meeting 39

June 2006 Hal Caswell -- Markov Anniversary Meeting 39

Right whale 40 35 Life expectancy (yrs) 30 25 20 15 10 5 0

Right whale 40 35 Life expectancy (yrs) 30 25 20 15 10 5 0 June 2006 calf imm mature Hal Caswell -- Markov Anniversary Meeting mom post-mom 40

Right whale 1. 4 CV of life expectancy 1. 2 1 0. 8 0.

Right whale 1. 4 CV of life expectancy 1. 2 1 0. 8 0. 6 0. 4 0. 2 0 June 2006 calf imm mature Hal Caswell -- Markov Stage Anniversary Meeting mom post-mom 41

June 2006 Hal Caswell -- Markov Anniversary Meeting 42

June 2006 Hal Caswell -- Markov Anniversary Meeting 42

June 2006 Hal Caswell -- Markov Anniversary Meeting 43

June 2006 Hal Caswell -- Markov Anniversary Meeting 43

June 2006 Hal Caswell -- Markov Anniversary Meeting 44

June 2006 Hal Caswell -- Markov Anniversary Meeting 44

June 2006 Hal Caswell -- Markov Anniversary Meeting 45

June 2006 Hal Caswell -- Markov Anniversary Meeting 45

June 2006 Hal Caswell -- Markov Anniversary Meeting 46

June 2006 Hal Caswell -- Markov Anniversary Meeting 46

June 2006 Hal Caswell -- Markov Anniversary Meeting 47

June 2006 Hal Caswell -- Markov Anniversary Meeting 47

June 2006 Hal Caswell -- Markov Anniversary Meeting 48

June 2006 Hal Caswell -- Markov Anniversary Meeting 48

June 2006 Hal Caswell -- Markov Anniversary Meeting 49

June 2006 Hal Caswell -- Markov Anniversary Meeting 49

June 2006 Hal Caswell -- Markov Anniversary Meeting 50

June 2006 Hal Caswell -- Markov Anniversary Meeting 50

The birth interval • • • interval between births determines birth rate varies over

The birth interval • • • interval between births determines birth rate varies over time responds to environment especially important in species producing few offspring • a special case of the “timing problem” • calculation uses machinery for absorbtion times, but conditional times June 2006 Hal Caswell -- Markov 51 Anniversary Meeting

Modified life cycle graph reproduce before dying died before breeding June 2006 Hal Caswell

Modified life cycle graph reproduce before dying died before breeding June 2006 Hal Caswell -- Markov Anniversary Meeting 52

June 2006 Hal Caswell -- Markov Anniversary Meeting 53

June 2006 Hal Caswell -- Markov Anniversary Meeting 53

June 2006 Hal Caswell -- Markov Anniversary Meeting 54

June 2006 Hal Caswell -- Markov Anniversary Meeting 54

Right whale 12 Mean time to reproduction (yrs) 10 8 6 4 2 0

Right whale 12 Mean time to reproduction (yrs) 10 8 6 4 2 0 June 2006 calf imm mature Hal Caswell -- Markov Starting. Meeting stage Anniversary mom post-mom 55

Time variation • the vital rates of the right whale changed between 1980 and

Time variation • the vital rates of the right whale changed between 1980 and 1998 June 2006 Hal Caswell -- Markov Anniversary Meeting 56

0. 96 time trend best model 0. 94 Calf survival 0. 92 0. 9

0. 96 time trend best model 0. 94 Calf survival 0. 92 0. 9 0. 88 0. 86 0. 84 0. 82 1980 June 2006 1984 1988 Hal Caswell -- Markov Year Anniversary Meeting 1992 1996 57

1 time trend best model 0. 95 Mother survival 0. 9 0. 85 0.

1 time trend best model 0. 95 Mother survival 0. 9 0. 85 0. 8 0. 75 0. 7 0. 65 0. 6 1980 June 2006 1984 1988 Hal Caswell Year -- Markov Anniversary Meeting 1992 1996 58

0. 5 time trend best model 0. 45 Birth probability 0. 4 0. 35

0. 5 time trend best model 0. 45 Birth probability 0. 4 0. 35 0. 3 0. 25 0. 2 0. 15 0. 1 1980 June 2006 1984 1988 Hal Caswell Year -- Markov Anniversary Meeting 1992 1996 59

June 2006 Hal Caswell -- Markov Anniversary Meeting 60

June 2006 Hal Caswell -- Markov Anniversary Meeting 60

70 period Life expectancy 60 50 40 30 20 10 1980 June 2006 1982

70 period Life expectancy 60 50 40 30 20 10 1980 June 2006 1982 1984 1986 1988 1990 Hal Caswell -- Markov Year Anniversary Meeting 1992 1994 1996 1998 61

June 2006 Hal Caswell -- Markov Anniversary Meeting 62

June 2006 Hal Caswell -- Markov Anniversary Meeting 62

June 2006 Hal Caswell -- Markov Anniversary Meeting 63

June 2006 Hal Caswell -- Markov Anniversary Meeting 63

June 2006 Hal Caswell -- Markov Anniversary Meeting 64

June 2006 Hal Caswell -- Markov Anniversary Meeting 64

June 2006 Hal Caswell -- Markov Anniversary Meeting 65

June 2006 Hal Caswell -- Markov Anniversary Meeting 65

70 period cohort Life expectancy 60 50 40 30 20 10 1980 June 2006

70 period cohort Life expectancy 60 50 40 30 20 10 1980 June 2006 1982 1984 1986 1988 1990 Hal Caswell -- Markov Year Anniversary Meeting 1992 1994 1996 1998 66

Summary • stage-classified demography from Markov chains – – – – expected stage occupancy

Summary • stage-classified demography from Markov chains – – – – expected stage occupancy times variance in stage occupancy times expected longevity variance in longevity net reproductive rate generation time birth and other intervals period and cohort effects in variable envionments • perturbation analyses • connection to data • things don’t look good for the right whale June 2006 Hal Caswell -- Markov Anniversary Meeting 67