Final Report Summary - SEABIRDPOP (Seabird population genetics, structure and biogeography) A summary description of the project objectivesAs global biodiversity is rapidly eroding, the preservation of species and their intra-specific diversity is an urgent challenge. Many seabirds are slipping dangerously close to extinction and seabird numbers have deteriorated faster than most other groups. Molecular methods and population modelling can be used to answer various questions important for species conservation. This project has three main objectives. First, we will trial an accurate method to census seabird colonies and analyse kinship even when the birds are absent. Indeed, one difficulty of working with seabirds is that they are often located in areas difficult to access and study trips are usually of limited duration. Second, we will determine how seabird populations are connected and if meta-populations occur. The grey-faced petrel (Pterodroma macroptera gouldi) and the Yelkouan shearwater (Puffinus yelkouan) both have unclear conservation status even if the latter has been recently listed as Vulnerable by the IUCN. Humans have had a marked impact on their range and many local populations have gone extinct or contracted to very small sizes. It is crucial to evaluate gene flow and meta-population occurrence to identify threatened populations. Third, we will analyse how seabird population diversity is distributed and what are the factors that influence their distribution. We will use a range of various molecular techniques, population modelling and biogeographical analyses to reach these objectives. The fellow will obtain the skills necessary to use the full toolkit of molecular methods currently available to ecologists and to perform meta-population modelling analyses. Once learned, these skills will be easily transferred to other conservation programs in Europe. This project will help to define units below the species level (Evolutionary Significant Units, Adaptative Units, Designatable Units) to accurately assess the extinction probability and to help set conservation priorities.A description of the work performed since the beginning of the project- With collaborators twenty 1 kg soil samples were collected from 10 plots on the seabird island of Little Barrier. Next generation sequencing data were obtained from PCR products amplified from DNA extracted from soil using the following markers: 16S, 18S, trnL, ITS, COI. However, no seabird DNA was detected in these analyses.- All the blood and tissue samples of grey-faced petrels (n = 245) and Yelkouan shearwaters (n = 226) have been collected in New Zealand and the Mediterranean Basin, respectively.- We obtained cytochrome b sequences and genotypes for 12 microsatellite loci for the 245 samples of grey-faced petrels. We also obtained cytochrome b sequences for the 226 samples of Yelkouan shearwaters. Genotypes for 14 microsatellite loci for 192 samples of Yelkouan shearwaters will be obtained by the end of this year.- We analyzed mtDNA and microsatellite data for grey-faced petrels and mtDNA data for Yelkouan shearwaters.- We gathered data for ~150 islands greater than 5 ha around the North Island of New Zealand to analyze grey-faced petrel biogeography. As petrels can breed on smaller islands and we would like to perform this analysis on several species, we need to gather more data.- We completed a research project complementary to the core of the SeabirdPop project which is dedicated to genetics but aims to understand the functioning of seabird populations and factors affecting the variation in this functioning. This additional project mainly aimed to analyze the influence of grey-faced petrel adult foraging strategies on breeding success and chick growth. East and West coast colonies were monitored for breeding success and chick development as well as for adult foraging strategy during the 2013 and 2014 breeding seasons. We deployed geolocators and GPS devices to identify foraging areas, determined the frequency of chick feeding and adult foraging trip duration, and evaluated trophic position by stable isotope analyses of adult and chick diet and their prey. This additional project allowed us to enlarge the multi-disciplinary approach of the project and the researcher to acquire new skills in spatial and trophic ecology.- The researcher was trained in island and seabird conservation and ecology, and in molecular ecology through the attendance of conferences, meeting and courses, as well as through the development of collaborations.A description of the main results achieved so far- As suggested by analyses from another team research by using mitochondrial control region and microsatellites, grey-faced petrels lack genetic structure in our study area due to high gene flow. Both mtDNA (cytochrome b) and microsatellites suggest panmixia (no barriers to gene flow between our study sites). The haplotype network revealed a ‘star-like’ pattern: although there is high haplotype diversity, most haplotypes occur at a very low frequency and are little differentiated from a dominant (probably ancestral) haplotype. This pattern is indicative of a bottleneck event followed by population expansion.- The analysis of mtDNA (cytochrome b) revealed a lack of phylogeographical structure in the Yelkouan shearwater. Tajima’s D, ‘star-like’ haplotype network and coalescent analysis suggest a population expansion (starting ~25 ka before present) potentially after a bottleneck event. A few individuals exhibited Balearic shearwater haplotypes. While it was known that hybridization between the two species occurred in Balearic Islands, our results show that hybridization occurs in both taxa, in both ways. The coalescent analysis dated the most recent common ancestor between the two species to ~400 ka before present.- We found that grey-faced petrel chicks on the West coast grew faster and reached higher body condition than those on the East coast. In addition, breeding success on the West coast was higher. Grey-faced petrels breeding on the East coast tended to travel further from their breeding ground to feed, foraging for a longer period and thus fed their chicks less frequently. Stable isotope analyses revealed different δ15N and δ13C values between East and West coast breeders suggesting the use of different trophic levels and foraging habitats during chick rearing. These results of exclusive colony foraging areas are starkly contrasting to the genetics results, and provide a rich combined dataset for exploring the population structuring traits of grey-faced petrels.- The researcher published 9 papers, 3 further are in preparation and 1 is submitted.The expected final results and their potential impact and useOur studies are state-of-the-art through their combination of field ecology, population genetics, trophic ecology, and biogeographic modelling, and through genetic data analysis using recent approaches such as landscape genetics and historical demography. Moreover, the meta-population scale will strengthen the global inference and applicability of results. Studies such as this are most powerful for conservation policy guidance. Such an integrative approach to map conservation ‘hotspots’ using multiple methodological descriptors has never been undertaken. Biological diversity conservation requires defining units below species level to accurately assess extinction probability and to help set priorities for conservation. Conservation units are important for management, pinpointing discrete components within the evolutionary legacy of a species and are particularly relevant for conservation of endemic species strongly affected by habitat degradation, introduced species and climate change. However, no study has examined their relevance to seabird conservation, a complex taxa regularly moving between terrestrial and marine environments.An understanding of seabird diet and foraging strategy is integral to their conservation and management, as monitoring seabird trophic niche dimensions, foraging areas and reproductive parameters can elucidate causes for population declines. Ultimately, we also aim to test for the influence of genetic parameters on reproductive performances and foraging strategies.
