The promise and limits of DNA based approach to infer diet flexibility in endangered top predators

Abstract

work, the authors assessed the nature and spatio-temporal flexibility of the foraging behaviour and consequent diet of the endangered petrel Procellaria westlandica from New-Zealand through metabarcoding of faeces samples. The results of this dDNA, non-invasive approach, identify some expected and also unexpected prey items, some of which require further investigation likely due to large gaps in the reference databases. They also reveal the temporal (before and after hatching) and spatial (across colonies only 1.5km apart) flexibility of the foraging behaviour, additionally suggesting a possible influence of fisheries activities in the surroundings of the colonies. This study thus both underlines the power of the non-invasive metabarcoding approach on faeces, and the important results such analysis can deliver for conservation, pointing a potential for diet flexibility that may be essential for the resilience of this iconic yet endangered species. The authors have used metabarcoding of environmental DNA from fecal samples of tāiko (Procellaria westlandica), an endangered New Zealand seabird, to better understand its foraging behavior and trophic ecology. Two seasons and two sub-colonies were compared to assess temporal and spatial variation in the potential diets of tāiko. The authors found that surprisingly, talitrid amphipods dominated both the frequency of occurrence and relative number of sequence reads in the fecal samples from tāiko. However, more consistent with expectations, fish and cephalopods were also significant components of tāikos diet – with an important commercial deep-sea species (hoki) featuring prominently, thus suggesting a potential conflict with the fishing industry due to bycatch. DNA foraging Storm-Petrels Hydrobates 8:87-94.