Lincoln-Petersen method: Closed populations, single marking event
Schnabel method: Closed populations, multiple marking and recapture events, equal probability of capture within a given sampling occasion but probabilities can vary between sampling periods.
CAPTURE: Closed populations, multiple marking and recapture events, unequal probability of capture due to:
Individual differences in capture probabilities
Differences in capture probabilities associated with a behavioral response to trapping
Differing capture probabilities between sampling periods (Schnabel model)
Jolly-Seber method: Open populations, equal probability of capture, multiple marking and recapture events
Jolly (1965) and Seber (1965) submitted idea separately.
Model estimates population size, "mortality" rates (i.e., deaths + emmigration), and "births" (i.e., births + immigration)
mt = Number of marked animals caught in sample t
ut = Number of unmarked animals caught in sample t
nt = Total number of animals caught in sample t
= mt + ut
st = Total number of animals released after sample t
= nt - accidental deaths or removals
Rt = Number of the st individuals released at sample t and caught again in some later sample
Zt = Number of individuals marked before sample t, not caught in sample t, but caught in some sample after sample t
Example From Krebs, C. J. 1989. Ecological Methodology.
Capture history for field voles:
Øt = Loss rate. Probability of survival from sample time t to sample time t + 1.
= Staying alive in the study area. Individuals which emigrate are counted as losses just as individuals that die.
Population is geographically closed.
Every animal present in the population (marked and unmarked) has the same probability of capture in sample t.
Every marked animal present in the population immediately after the ith sample has the same probability of survival (Øi) until the (t + 1)th sampling time.
Marks are not lost or overlooked.
Sampling time is negligible in relation to intervals between samples (i.e., demographic closure is satisfied during each sampling occasion) and each release is made immediately after the sample.