Importance of accounting for detection heterogeneity when estimating abundance: the case of French wolves.
Assessing conservation strategies requires reliable estimates of abundance. Because detecting all individuals is most often impossible in free-ranging populations, estimation procedures have to account for a <1 detection probability. Capture-recapture methods allow biologists to cope with this issue of detectability. Nevertheless, capture-recapture models for open populations are built on the assumption that all individuals share the same detection probability, although detection heterogeneity among individuals has led to underestimating abundance of closed populations. We developed multievent capture-recapture models for an open population and proposed an associated estimator of population size that both account for individual detection heterogeneity (IDH). We considered a two-class mixture model with weakly and highly detectable individuals to account for IDH. In a noninvasive capture-recapture study of wolves we based on genotypes identified in feces and hairs, we found a large underestimation of population size (27% on average) occurred when IDH was ignored.
Cubaynes
Sarah
S
Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, Campus CNRS, 1919 Route de Mende, F-34293 Montpellier Cedex 5, France. sarah.cubaynes@cefe.cnrs.fr
Pradel
Roger
R
Choquet
Rémi
R
Duchamp
Christophe
C
Gaillard
Jean-Michel
JM
Lebreton
Jean-Dominique
JD
Marboutin
Eric
E
Miquel
Christian
C
Reboulet
Anne-Marie
AM
Poillot
Carole
C
Taberlet
Pierre
P
Gimenez
Olivier
O
D000823:Animal Identification Systems; D000818:Animals; D001699:Biometry / Q000379:methods*; D005243:Feces; D005602:France; D006197:Hair; D015233:Models, Statistical; D011156:Population Density; D019596:Wolves