Chronic lack of breeding by Galápagos Blue-footed Boobies and associated population decline

Anchundia, David; Huyvaert, Kathryn P.; Anderson, David J.

doi:10.5751/ace-00650-090106

Cited by 16 publications

(20 citation statements)

References 47 publications

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“…Although nesting effort was better in colonies on the range peripheries, it was still sub-optimal. This breeding failure in pelicans was similar to that observed in many other Pacific seabirds (e.g., Anchundia et al 2014, Humphries et al 2015, MacCall et al 2016), but apparently not universal in all Pacific seabirds .…”

Section: Synthesis and Conclusionsupporting

confidence: 86%

Brown Pelicans, Pelecanus occidentalis californicus (Aves: Pelecanidae): Five decades with ENSO, dynamic nesting, and contemporary breeding status in the Gulf of California

et al. 2017

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The California Brown Pelican subspecies (Pelecanus occidentalis californicus) was removed from the US endangered species list in 2009, along with the entire species of Brown Pelican throughout North America. The Gulf of California subpopulation within the entire metapopulation (= subspecies) comprises the majority of nesting (~76% of P. o. californicus). The US classifications were based on pollution effects in the Southern California Bight (SCB) during the early 1970s; official listing-recognition in Mexico (NOM-059-SEMARNAT-2010) occurred in 2010 and it continues. Unfortunately, Brown Pelican conservation across the US/Mexico border has been largely uncoordinated. Recent declines in the SCB subpopulation are not well-documented, whereas representative subpopulations in the Gulf of California have received continual study since the US listing. Until the early 2000s, Gulf pelican breeding populations changed little. El Niño/Southern Oscillation continues to be a major factor driving annual pelican breeding intensity and success, with a slightly weaker effect to the north. Nest attempts (NA) in the southern Midriff zone and to the south of our monitoring zone have declined in the last decade, in especially extreme and unprecedented ways in a period of unusual warming in the last 3 years (2014-2016), termed by some as the "Blob". Other factors (such as human disturbance and commercial fishing) have likely exacerbated recent warming effects in some areas. Recent data also suggest the pelican is in a process of minor range-shifting toward the northern Gulf, and there are no definitive indications of a recent NA decline in that zone. Monitoring over the entire range, past 2016, will be important to determine whether populations have begun a long-term decline or will recover to normal baseline levels. The health of pelican populations is an important indicator of overall ecological health in the Pacific region and not an isolated phenomenon.

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Section: Synthesis and Conclusionsupporting

confidence: 86%

Brown Pelicans, Pelecanus occidentalis californicus (Aves: Pelecanidae): Five decades with ENSO, dynamic nesting, and contemporary breeding status in the Gulf of California

et al. 2017

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“…Taking low-frequency oscillations into account is at an early stage but is absolutely necessary in the context of global warming. Failing to consider low-frequency oscillations among the possible causes of fluctuations in tropical seabirds (Anchundia et al 2014) could lead to strong bias in reporting responses to regional climate warming.…”

Section: Discussionmentioning

confidence: 99%

“…Nevertheless, they cause large changes to marine ecosystems (Alheit et al 2009), such as alternative regimes of sardines and anchovy abundance observed across the major upwelling areas of the world (Lluch-Cota 2013). Demographic and behavioral responses of high trophic-level predators to these regime shifts have been suggested (Lusseau et al 2004, Baker et al 2012, Hatch 2013, Anchundia et al 2014, Tompkins et al 2017) but, to our knowledge, never documented in detail, in particular for survival rates. Seabirds, mammals, and reptiles have complex life cycles with delayed maturity and intermittent reproduction that are not easily amenable to demographic analysis (deYoung 2004).…”

Section: Introductionmentioning

confidence: 92%

Pacific Decadal and El Niño oscillations shape survival of a seabird

Guillemain

Lebreton

Drummond³

et al. 2018

Ecology

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Understanding and modeling population change is urgently needed to predict effects of climate change on biodiversity. High trophic-level organisms are influenced by fluctuations of prey quality and abundance, which themselves may depend on climate oscillations. Modeling effects of such fluctuations is challenging because prey populations may vary with multiple climate oscillations occurring at different time scales. The analysis of a 28-yr time series of capture-recapture data of a tropical seabird, the Nazca Booby (Sula granti), in the Galápagos, Ecuador, allowed us to test for demographic effects of two major ocean oscillations occurring at distinct time-scales: the inter-annual El Niño Southern Oscillation (ENSO) and inter-decadal oscillations. As expected for a tropical seabird, survival of fledgling birds was highly affected by extreme ENSO events; by contrast, neither recruitment nor breeding participation were affected by either ENSO or decadal oscillations. More interesting, adult survival, a demographic trait that canalizes response to environmental variations, was unaffected by inter-annual ENSO oscillations yet was shaped by the Pacific Decadal Oscillation and small pelagic fish regime. Adult survival decreased during oceanic conditions associated with higher breeding success, an association probably mediated in this species by costs of reproduction that reduce survival when breeding attempts end later. To our knowledge, this is the first study suggesting that survival of a vertebrate can be vulnerable to a natural multidecadal oscillation.

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“…This result adds to the current evidence of an overall declining trend in seabird populations around the world (Croxall et al 2012, Paleczny et al 2015 and extends its confirmation to the warm eastern tropical Pacific. Declining numbers of these boobies have also been documented in the Galápagos Archipelago by comparing estimates of population size from the 2000s with estimates from the 1960s (Anchundia et al 2014), suggesting this negative trend could be taking place throughout the entire distribution range of this species. Interestingly, although l decreased over time, the long-term average suggests population increase (mean l  1.11  0.052).…”

Section: Discussionmentioning

confidence: 84%

“…In this study, we used 23 yr of data to investigate how adult survival, local recruitment, and their relative contributions to population growth (l) vary over time in the blue-footed booby, a long-lived locally foraging seabird that breeds on islands in the warm eastern tropical Pacific (Nelson 2005). Chronic lack of breeding by blue-footed boobies and low counts of breeding pairs and juveniles have been observed in recent years in the Galápagos Archipelago, suggesting that population numbers of these tropical boobies could be declining (Anchundia et al 2014). Our study population in Mexico contains a large number and proportion (∼ 90% in 2006) of marked individuals for which survival and recruitment probabilities can be estimated.…”

mentioning

confidence: 91%

Long‐term population dynamics reveal that survival and recruitment of tropical boobies improve after a hurricane

Ancona

Drummond

Rodrı́guez

et al. 2016

Journal of Avian Biology

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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.

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Chronic lack of breeding by Galápagos Blue-footed Boobies and associated population decline

Cited by 16 publications

References 47 publications

Brown Pelicans, Pelecanus occidentalis californicus (Aves: Pelecanidae): Five decades with ENSO, dynamic nesting, and contemporary breeding status in the Gulf of California

Brown Pelicans, Pelecanus occidentalis californicus (Aves: Pelecanidae): Five decades with ENSO, dynamic nesting, and contemporary breeding status in the Gulf of California

Pacific Decadal and El Niño oscillations shape survival of a seabird

Long‐term population dynamics reveal that survival and recruitment of tropical boobies improve after a hurricane

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