TY - JOUR T1 - An efficient extension of N-mixture models for multi-species abundance estimation JF - bioRxiv DO - 10.1101/073577 SP - 073577 AU - Juan Pablo Gomez AU - Scott K. Robinson AU - Jason K. Blackburn AU - José Miguel Ponciano Y1 - 2016/01/01 UR - http://biorxiv.org/content/early/2016/11/16/073577.abstract N2 - 1. In this paper we propose an extension of the N-mixture family of models that targets an improvement of the statistical properties of the rare species abundance estimators when sample sizes are low, yet of typical size in tropical studies. The proposed method harnesses information from other species in an ecological community to correct each species' estimator. We provide guidance to determine the sample size required to estimate accurately the abundance of rare tropical species when attempting to estimate the abundance of single species.2. We evaluate the proposed methods using an assumption of 50m radius plots and perform simulations comprising a broad range of sample sizes, true abundances and detectability values and a complex data generating process.3. The extension of the N-mixture model is achieved by assuming that the detection probabilities of a set of species are all drawn at random from a beta distribution in a multi-species fashion. This hierarchical model avoids having to specify a single detection probability parameter per species in the targeted community. Parameter estimation is done via Maximum Likelihood.4. We compared our multi-species approach with previously proposed multispecies N-mixture models, which we show are biased when the true abundances of species in the community are less than seven individuals per 100ha. The beta N-mixture model proposed here outperforms the traditional Multi-species N-mixture model by allowing the estimation of organisms at lower densities and controlling the bias in the estimation.5. We illustrate how our methodology can be used to suggest sample sizes required to estimate the abundance of organisms, when these are either rare, common or abundant. When the interest is full communities, we show how the multi-species approaches, and in particular our beta model and estimation methodology, can be used as a practical solution to estimate organism densities from rapid inventories datasets. The statistical inferences done with our model via Maximum Likelihood can also be used to group species in a community according to their detectabilities. ER -