Finding the last Hawkweed plant: how detection rate scales with cluster size

Abstract

When surveying or monitoring a species, the assumption that all the individuals living in the sampling area will be detected rarely holds. Even for plants, detection probabilities are typically less than 1 (where 1 represents perfect detection). Detectability estimates can be affected by ecological processes, observational processes, and by the interactions between the two. For invasive species control programs understanding the factors affecting detectability is critical to determining the effort needed to reduce population density to a desired level, or prevent their establishment in new areas. The influence of cluster size on detection rate was investigated in the context of Orange Hawkwe..