Data from: Long-term population dynamics reveal that survival and recruitment of tropical boobies improve after a hurricane
Ancona, Sergio; Drummond, Hugh; Rodríguez, Cristina; Zuñiga-Vega, José Jaime (2016), Data from: Long-term population dynamics reveal that survival and recruitment of tropical boobies improve after a hurricane, Dryad, Dataset, https://doi.org/10.5061/dryad.h0qp0
Variability in population numbers is a central issue in evolutionary ecology and also in biodiversity conservation. However, for most seabirds this information is lacking and tropical populations are virtually unstudied. Long-term studies are warranted because world’s seabird populations exhibit an overall declining trend since 1950. Using data spanning 23 years, we investigated how adult survival, local recruitment, and their relative contributions to population growth (λ) vary over time in the blue-footed booby (Sula nebouxii), a long-lived locally foraging seabird that breeds in tropical waters. In addition, we investigated whether booby demographic rates exhibit the same declining trend observed in other seabirds, whether these rates are impacted by hurricanes, and whether these potential impacts differ between sexes. Our analysis of 4608 capture-recapture histories revealed that survival and recruitment were nearly equal between males and females, exhibited a declining trend over the last 23 years, and in both sexes, these vital rates improved after a hurricane. The declining trend in recruitment was slightly more attenuated in males. These results add to the current evidence for an overall declining trend in world’s seabird populations and extend its confirmation to the warm eastern tropical Pacific. Moreover, they provide the first evidence that hurricanes may favor natural populations. As a result of the declining trend and variation in survival and recruitment, λ exhibited a slight decline and substantial variation over the 23 years. However, most λ values were equal to or higher than 1, and the long-term average indicates population increase. The ability of blue-footed boobies to maintain a positive population balance despite of negative trends in their vital rates might result from canalization of adult survival (the vital rate that contributes most to λ and shows lower variation compared to recruitment) against environmental variability.
eastern tropical Pacific