The relative contribution of camera trap technology and citizen science for estimating survival of an endangered African vulture

Andrea Santangeli,Veli-Matti Pakanen,Peter Bridgeford,Mark Boorman,Holger Kolberg,Ana Sanz-Aguilar

doi:10.1016/j.biocon.2020.108593

Abstract

Technological advances such as camera traps, and citizen science, coupled with advanced quantitative approaches, can help fill existing knowledge gaps and aid effective conservation.We combine citizen and camera trap observations to estimate survival of the Endangered lappet-faced vulture, assess the relative contribution of data from camera traps and citizens, as well as impact of loss of individual marks (wing tags), on survival estimates.We used data from 762 lappet-faced vultures wing tagged as nestlings during 2006–2017 in western Namibia. Observations of wing tagged individuals were provided by citizens or via camera traps. We formulated a multievent capture-mark-recapture model to estimate survival while accounting for probabilities of resighting by citizens and/or camera traps, recovery of dead individuals, and loss of the wing tag.Survival was relatively high for juveniles (0.79), and increased with age to 0.95. Citizen observations of live and dead birds were low in number. However, when combined with camera trap resightings of live individuals, citizen observations increased the precision of survival estimates of birds older than one year compared to using data from either sources separately. Wing tag loss was high after 5–6 years of tag age. If neglected, tag loss can result in severe underestimation of survival of the older age classes.Overall, we show that filling ecological knowledge gaps is possible through the efficient use of data provided by different sources, and by applying state-of the art approaches that minimise potential biases, such as those due to tag loss.

Highlights

Biodiversity is being lost worldwide at unprecedented rates (IPBES, 2019)
We aim to i) assess the relative contribution of data provided by a citizen science program aimed at reporting live vultures with a wing tag, and the recapture data provided by a more recent camera trap program; ii) quantify the survival rate of lappet-faced vultures by age classes; iii) quantify the potential bias on survival estimates due to ignoring the loss of wing tags
We have shown that camera trap observations, even if based on very few camera trap locations, can, under specific conditions, provide a large amount of resighting observations that dominate the share of total live resightings compared to citizen observations

Summary

Introduction

Biodiversity is being lost worldwide at unprecedented rates (IPBES, 2019). Averting the collapse of biodiversity and the associated ecosystem services it supports may still be possible, but increased efforts are required (Ceballos et al, 2015; IPBES, 2019). Adequate information on key demographic parameters, such as birth and death rates, is available from only 1.3% of the world's tetrapod species (Conde et al, 2019). This lack of basic ecological knowledge hinders species conservation policies, which, under urgent and critical circumstances, are often designed and implemented in the dark (Cook et al, 2010)

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