by Clara Casabona i Amat
Site occupancy models are models that take into account the imperfect detection of organisms to determine the probability of presence of a species at a site. They can be considered as an extension of generalized linear mixed effects models (GLMM). In databases from sampled biological communities, the presence of a species at a site can mean two things: either the species is present in that site and the species was detected. However, the absence of a species at a site can be the result of two phenomena: the species is not present or the species is present, but has not been detected. In occupancy models, we can quantify this uncertainty related to the detection of a species by using sites that have been visited at least twice. We will discuss these issues and practice with examples of applications using the R package unmarked
.