Chapter 4: Estimating Vital Rates Flashcards
non-invasive capture and mark methods: sources of error
- genotypic error
- shadow effect
genotypic error
two or more individuals that share the same genetic ID or physical markings are counted as same individuals
genotypic error example
increased number of loci
shadow effect
same individual counted as multiple individuals in analyses
shadow effect example
hair cells of two individuals are amplified together, creating a ‘new’ individual
SCR - Spatial Capture Recapture Methods
- new class of sophisticated closed CMR methods
- incorporates spatial information of captures to estimate location and number of animal home ranges
SCR example
- R packages
- Bayesian approaches
open population models
- some caught, other dead or gone
- additions or losses are of interest
additions
- birth
- immigration
losses
- death
- emigration
Jolly Seber Abundance
Ni = Mi* ni / mi
Mi
estimate of number of marked animals alive in the population right before occasion i
how is abundance estimated
with closed-population models within each primary period
how gains and losses are estimated across the primary period
using open-population models
open population models examples
- survival
- recruitment
- emigration
- immigration
factors of survival estimation
- known fate
- CMR
- band recovery/return
known fate
all animals can be relocated
CMR (Cormack-Jolly-Seber)
only survivors are recorded
band recovery/return
- only deaths are recorded
- marked alive, bands returned via harvest
known fate models
S = x/n
S
survival
x
number of surviving animals
n
total number of sampled animals
Kaplan Meier Methods
S(t) = pi [1- (# of deaths at time i=di/ # at risk at time i=ri)]
Kaplan-Meier Methods accommodates…
- multiple intervals of sampling
- right censoring of animals with unknown fate
- staggered entry of new animals
assumptions of Known-Fate survival methods
- marked animals are representative of the population
- the mark/sensor does not affect survival
- censoring is unrelated to their fate
- survival times are independent for the different animals
survival estimation allows for:
estimating the effects of different variables
measuring reproduction: proportion breeding
- observation
- non-invasive genetic markers
- hormone assays
non-invasive genetic markers example
paternity/maternity
factor to tell how many babies per mom
- natality
- fecundity
- average reproduction contribution
natality
average number of live offspring per female that reproduces
examples of natality
- litter size
- clutch size
fecundity
average number of offspring born per individual of a given age in one time step
average reproduction contribution
product of fecundity and either the survival of young to be counted the next year or the survival of parents to have the young
sex ratios
- ratio of males to females
- varies through different lineages
sex ratio driving factors
- temperature
- food availability
- males often have a lower survival
sex ratio driving factors: temperature
- climate change
- styrofoam boxes
food availability
sex allocation theory
sex ratio driving factors: males often have a lower survival
- more risky behaviors
- high susceptibility to disease and parasites
- X linked genetic problems
