Browsing by Author "Wanless, Ross M."
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- A framework for mapping the distribution of seabirds by integrating tracking, demography and phenologyPublication . Carneiro, Ana Paula B.; Pearmain, Elizabeth J.; Oppel, Steffen; Clay, Thomas A.; Phillips, Richard A.; Bonnet‐Lebrun, Anne‐Sophie; Wanless, Ross M.; Abraham, Edward; Richard, Yvan; Rice, Joel; Handley, Jonathan; Davies, Tammy E.; Dilley, Ben J.; Ryan, Peter G.; Small, Cleo; Arata, Javier; Arnould, John P. Y.; Bell, Elizabeth; Bugoni, Leandro; Letizia, Campioni; Catry, Paulo; Cleeland, Jaimie; Deppe, Lorna; Elliott, Graeme; Freeman, Amanda; Gonzalez-Solis, Jacob; Granadeiro, José Pedro; Grémillet, David; Landers, Todd J.; Makhado, Azwianewi; Nel, Deon; Nicholls, David G.; Rexer‐Huber, Kalinka; Robertson, Christopher J. R.; Sagar, Paul M.; Scofield, Paul; Stahl, Jean‐Claude; Stanworth, Andrew; Stevens, Kim L.; Trathan, Philip N.; Thompson, David R.; Torres, Leigh; Walker, Kath; Waugh, Susan M.; Weimerskirch, Henri; Dias, Maria P.1. The identification of geographic areas where the densities of animals are highest across their annual cycles is a crucial step in conservation planning. In marine environments, however, it can be particularly difficult to map the distribution of species, and the methods used are usually biased towards adults, neglecting the distribution of other life-history stages even though they can represent a substantial proportion of the total population. 2. Here we develop a methodological framework for estimating populationlevel density distributions of seabirds, integrating tracking data across the main life-history stages (adult breeders and non-breeders, juveniles and immatures). We incorporate demographic information (adult and juvenile/immature survival, breeding frequency and success, age at first breeding) and phenological data (average timing of breeding and migration) to weight distribution maps according to the proportion of the population represented by each life-history stage. 3. We demonstrate the utility of this framework by applying it to 22 species of albatrosses and petrels that are of conservation concern due to interactions with fisheries. Because juveniles, immatures and non-breeding adults account for 47%–81% of all individuals of the populations analysed, ignoring the distributions of birds in these stages leads to biased estimates of overlap with threats, and may misdirect management and conservation efforts. Population-level distribution maps using only adult distributions underestimated exposure to longline fishing effort by 18%–42%, compared with overlap scores based on data from all lifehistory stages. 4. Synthesis and applications. Our framework synthesizes and improves on previous approaches to estimate seabird densities at sea, is applicable for data-poor situations, and provides a standard and repeatable method that can be easily updated as new tracking and demographic data become available. We provide scripts in the R language and a Shiny app to facilitate future applications of our approach. We recommend that where sufficient tracking data are available, this framework be used to assess overlap of seabirds with at-sea threats such as overharvesting, fisheries bycatch, shipping, offshore industry and pollutants. Based on such an analysis, conservation interventions could be directed towards areas where they have the greatest impact on populations.
- Understanding the mechanisms of antitropical divergencein the seabird White-faced Storm-petrel (Procellariiformes:Pelagodroma marina) using a multilocus approachPublication . Silva, Mónica C.; Matias, Rafael; Wanless, Ross M.; Ryan, Peter G.; Stephenson, Brent M.; Bolton, Mark; Ferrand, Nuno; Coelho, Manuela M.Analytical methods that apply coalescent theory to multilocus data have improved infer-ences of demographic parameters that are critical to understanding population divergenceand speciation. In particular, at the early stages of speciation, it is important to implementmodels that accommodate conflicting gene trees, and benefit from the presence of sharedpolymorphisms. Here, we employ eleven nuclear loci and the mitochondrial control regionto investigate the phylogeography and historical demography of the pelagic seabirdWhite-faced Storm-petrel (Pelagodroma marina)bysamplingsubspeciesacrossitsanti-tropical distribution. Groups are all highly differentiated: global mitochondrial ΦST= 0.89(P < 0.01) and global nuclear ΦSTvaries between 0.22 and 0.83 (all P < 0.01). The completelineage sorting of the mitochondrial locus between hemispheres is corroborated by approx-imately half of the nuclear genealogies, suggesting a long-term antitropical divergence inisolation. Coalescent-based estimates of demographic parameters suggest that hemisphericdivergence of P. marina occurred approximately 840 000 ya (95% HPD 582 000–1 170 000),in the absence of gene flow, and divergence within the Southern Hemisphere occurred190000ya(95%HPD96000–600 000), both probably associated with the profound palaeo-oceanographic changes of the Pleistocene. A fledgling sampled in St Helena (tropicalSouth Atlantic) suggests recent colonization from the Northern Hemisphere. Despite thegreat potential for long-distance dispersal, P. marina antitropical groups have beenevolving as independent, allopatric lineages, and divergence is probably maintained byphilopatry coupled with asynchronous reproductive phenology and local adaptation.