Improving distribution data of threatened species by combining acoustic monitoring and occupancy modelling

Abstract

Running title: Acoustic monitoring and occupancy modeling Summary 1. Conservation of threatened species relies on predictions about their spatial distribution; however, it is often difficult to detect species in the wild. The combination of acoustic monitoring to improve species detectability and statistical methods to account for false negative detections can improve species distribution estimates. 2. Here, we combine a novel automated species-specific identification approach with occupancy models that account for imperfect detectability to provide a more accurate species distribution map of the Elfin-woods warbler Setophaga angelae, a rare, elusive, and threatened bird species. We also compared three automated species identification/validation approaches to determine which approach provided occupancy estimates similar to manual validation of all recordings. Acoustic data were collected along three elevational gradients (95 to 1074 m a.s.l) in El Yunque National Forest, Puerto Rico. The detection matrices acquired through automated species-specific identification models and manual validations of all recordings were used to create occupancy models. 3. Although this species has a wider distribution than previously reported, it depends on Palo Colorado forest cover and it mainly occurs between 600 and 900 m a.s.l. Unbiased and precise occupancy models were developed by using automated species identification models and only manually validating 4% of the recordings. 4. Our approach draws on the strength of two active areas of ecological research: acoustic monitoring and occupancy modeling. Our methods provide an effective and efficient way to translate the enormous amount of acoustic information collected with passive acoustic monitoring devices into meaningful ecological data that can be applied to understand and map the distribution of rare, elusive and threatened species.

Autonomous recording units in avian ecological research: current use and future applications

“…ARUs can be programmed to record for a similar duration as point counts (e.g., 3-10 min), but can make several recordings per day and multiple surveys can be done over several days or months (e.g., Goyette et al 2011, Tegeler et al 2012. The increased temporal effort makes ARUs a useful tool for studying rare or elusive species that vocalize infrequently , Cerqueira and Aide 2016. A downside is that if an ARU fails to record, the loss of data could go unnoticed for a long time, making it imperative to check units before deployment.…”

“…Increasing the number of visits and sampling sites improves the accuracy and precision of occupancy estimates (Mackenzie et al 2002). Automated species recognition from ARUs can be an efficient method to obtain data from acoustic recordings for occupancy modeling (Cerqueira and Aide 2016). An issue with estimating occupancy is that interpreting the biological meaning of the results requires some knowledge of species movement and home range size.…”

Species Richness (of Insects) Drives the Use of Acoustic Space in the Tropics

“…In addition, each recording is a permanent record of multiple species, which provides invaluable information that can be analyzed by other researchers in the future [27]. To extract useful information from these audio recordings, researchers have identified species by listening to recordings [21,28,29], creating automated species identification algorithms [27,30], or using acoustic indices [31]. The manual approach requires expert knowledge and is time consuming, and this limits the number of recordings, species and sites that can be monitored.…”

The effect of industrial noise on owl occupancy in the boreal forest at multiple spatial scales

“…Passive acoustic surveys employing autonomous recording units (ARUs) set to record on a predetermined schedule, are becoming increasingly prevalent in avian research (Shonfield and Bayne 2017). ARUs have been found to be useful for surveying owls (Rognan et al 2012) as well as other rare and elusive species (Holmes et al 2014, 2015, Campos-Cerqueira and Aide 2016. ARUs can be left unattended in the field for extended periods, and by increasing the amount of time surveyed at a location, the likelihood that an owl occupies an area but goes undetected is reduced.…”