Fig 1.
Map of the Baja California Pacific Islands, a seabird hotspot where breeding populations have been systematically monitored for almost two decades.
Photos of Coronado Archipelago and San Roque islands are shown—being the extremes in geographic location—to show the heterogeneous physiography of the region’s islands. Arrows depict the southerly flow of the California Current [51], which has significant influence on the region’s marine productivity and thus the seabird populations. Map design credits: © GECI / Gabriela Fernández Ham. Photo credits: © GECI / J.A. Soriano.
Table 1.
Characteristics of the Baja California Pacific Islands where breeding seabird populations were monitored during the period 2003–2019.
Table 2.
Breeding status of the seabird populations on the Baja California Pacific Islands for the 2017–2019 breeding seasons.
Fig 2.
Seabird population trends on the Baja California Pacific Islands for the period 2014–2019.
Only species colonies that tested the following null hypotheses: Increasing population, H0: λ≤1, p<α = 0.1 (31 colonies, 14 species) and decreasing population, H0: λ≥1, p<α = 0.1 (11 colonies, 7 species) are shown.
Fig 3.
Population trends per taxonomic group.
Points represent the hierarchical bootstrapped means from the medians of the population growth rates (λ) shown in S1 Table. Bars represent the 95% bootstrap interval. The horizontal dashed line shows λ = 1 which indicates no population change.
Table 3.
Summary of population trends for 61 colonies of 19 seabird species on 10 islands and archipelagos in the Mexican Pacific off the Baja California Peninsula.
Fig 4.
Seabirds with a positive regional population trend on the Baja California Pacific Islands for the period 2014–2019.
For an increasing population, the following null hypothesis was tested: H0: λ≤1, p<α = 0.1.