Use of ambiguous detections to improve estimates from species distribution models

• Published in: Conservation biology 2019-02, Vol.33 (1), p.185-195
• Main Authors: Louvrier, Julie, Molinari‐Jobin, Anja, Kéry, Marc, Chambert, Thierry, Miller, David, Zimmermann, Fridolin, Marboutin, Eric, Molinari, Paolo, Müeller, Oliver, Černe, Rok, Gimenez, Olivier
• Format: Article
• Language: English
• Subjects: Carnivores; carnívoros mayores; Computer simulation; Conflicts; Conservation status; Cost benefit analysis; Data; Data processing; detección imperfecta de especies; Detection; Distribution; Ecological monitoring; Environmental Sciences; Estimates; false positives; Home range; large carnivores; lince; lynx; Lynx lynx; Mathematical models; modelos de ocupación; occupancy models; Parameter estimation; Parameters; positivos falsos; Species; species imperfect detection; Surveys; 假阳性; 占据模型; 大型食肉动物; 物种不充分检测; 猞猁
• ISSN: 0888-8892; 1523-1739
• DOI: 10.1111/cobi.13191

As large carnivores recover throughout Europe, their distribution needs to be studied to determine their conservation status and assess the potential for human‐carnivore conflicts. However, efficient monitoring of many large carnivore species is challenging due to their rarity, elusive behavior, and large home ranges. Their monitoring can include opportunistic sightings from citizens in addition to designed surveys. Two types of detection errors may occur in such monitoring schemes: false negatives and false positives. False‐negative detections can be accounted for in species distribution models (SDMs) that deal with imperfect detection. False‐positive detections, due to species misidentification, have rarely been accounted for in SDMs. Generally, researchers use ad hoc data‐filtering methods to discard ambiguous observations prior to analysis. These practices may discard valuable ecological information on the distribution of a species. We investigated the costs and benefits of including data types that may include false positives rather than discarding them for SDMs of large carnivores. We used a dynamic occupancy model that simultaneously accounts for false negatives and positives to jointly analyze data that included both unambiguous detections and ambiguous detections. We used simulations to compare the performances of our model with a model fitted on unambiguous data only. We tested the 2 models in 4 scenarios in which parameters that control false‐positive detections and true detections varied. We applied our model to data from the monitoring of the Eurasian lynx (Lynx lynx) in the European Alps. The addition of ambiguous detections increased the precision of parameter estimates. For the Eurasian lynx, incorporating ambiguous detections produced more precise estimates of the ecological parameters and revealed additional occupied sites in areas where the species is likely expanding. Overall, we found that ambiguous data should be considered when studying the distribution of large carnivores through the use of dynamic occupancy models that account for misidentification. Uso de Detecciones Ambiguas para Mejorar las Estimaciones a partir de Modelos de Distribución de Especies Resumen Conforme los carnívoros mayores se recuperan en toda Europa, su distribución requiere ser estudiada para determinar su estado de conservación y para evaluar el potencial de conflictos entre humanos y carnívoros. Sin embargo, el monitoreo eficiente de muchas especies de carní