Northern Breeding Range Expansion of Two Sula Species at Sutil Island, California, USA

Méndez Sánchez F., Bedolla Guzmán Y., Rojas Mayoral E., Aguirre-Muñoz A., Koleff P., Aguilar Vargas A., Álvarez Santana F., Arnaud G., Aztorga Ornelas A., Beltrán Morales L.F., Bello Yáñez M., Berlanga García H., Bravo Hernández E., Cárdenas Tapia A., Castellanos Vera A., et. al.

The Baja California Pacific Islands (BCPI) is a seabird hotspot in the southern California Current System supporting 129 seabird breeding populations of 23 species and over one million birds annually. These islands had a history of environmental degradation because of invasive alien species, human disturbance, and contaminants that caused the extirpation of 27 seabird populations. Most of the invasive mammals have been eradicated and colonies have been restored with social attraction techniques. We have recorded the number of breeding pairs annually for most of the colonies since 2008. To assess population trends, we analyzed these data and show results for 19 seabird species on ten island groups. The maximum number of breeding pairs for each nesting season was used to estimate the population growth rate (λ) for each species at every island colony. We performed a moving block bootstrap analysis to assess whether seabird breeding populations are increasing or decreasing. San Benito, Natividad, and San Jerónimo are the top three islands in terms of abundance of breeding pairs. The most widespread species is Cassin’s Auklet (Ptychoramphus aleuticus) with 14 colonies. Thirty-one populations of 14 species are significantly increasing while eleven populations of seven species are decreasing. We did not find statistical significance for 19 populations, however, 15 have λ>1 which suggest they are growing. Twelve of the 18 species for which we estimated a regional population trend are significantly increasing, including seven surface-nesting species: Brandt’s Cormorant (Phalacrocorax penicillatus), Brown Pelican (Pelecanus occidentalis), Caspian Tern (Hydroprogne caspia), Double-crested Cormorant (P. auritus), Elegant Tern (Thalasseus elegans), Laysan Albatross (Phoebastria immutabilis) and Western Gull (Larus occidentalis), and five burrow-nesting species: Ainley’s (Hydrobates cheimomnestes), Ashy (H. homochroa) and Townsend’s (H. socorroensis) Storm-Petrels, and Craveri’s (Synthliboramphus craveri) and Guadalupe (S. hypoleucus) Murrelets. The BCPI support between 400,000 and 1.4 million breeding individuals annually. Our results suggest that these islands support healthy and growing populations of seabirds that have shown to be resilient to extreme environmental conditions such as the “Blob”, and that such resilience has been strengthen from conservation and restoration actions such as the eradication of invasive mammals, social attraction techniques and island biosecurity.

Fiechter J., Pozo Buil M., Jacox M.G., Alexander M.A., Rose K.A.

Predicting changes in the abundance and distribution of small pelagic fish species in response to anthropogenic climate forcing is of paramount importance due to the ecological and socioeconomic importance of these species, especially in eastern boundary current upwelling regions. Coastal upwelling systems are notorious for the wide range of spatial (from local to basin) and temporal (from days to decades) scales influencing their physical and biogeochemical environments and, thus, forage fish habitat. Bridging those scales can be achieved by using high-resolution regional models that integrate global climate forcing downscaled from coarser resolution earth system models. Here, “end-to-end” projections for 21st century sardine population dynamics and catch in the California Current system (CCS) are generated by coupling three dynamically downscaled earth system model solutions to an individual-based fish model and an agent-based fishing fleet model. Simulated sardine population biomass during 2000–2100 exhibits primarily low-frequency (decadal) variability, and a progressive poleward shift driven by thermal habitat preference. The magnitude of poleward displacement varies noticeably under lower and higher warming conditions (500 and 800 km, respectively). Following the redistribution of the sardine population, catch is projected to increase by 50–70% in the northern CCS and decrease by 30–70% in the southern and central CCS. However, the late-century increase in sardine abundance (and hence, catch) in the northern CCS exhibits a large ensemble spread and is not statistically identical across the three downscaled projections. Overall, the results illustrate the benefit of using dynamical downscaling from multiple earth system models as input to high-resolution regional end-to-end (“physics to fish”) models for projecting population responses of higher trophic organisms to global climate change.

Smith J.A., Muhling B., Sweeney J., Tommasi D., Pozo Buil M., Fiechter J., Jacox M.G.

Osborne O., O’Hara P., Whelan S., Zandbergen P., Hatch S., Elliott K.

Marine heatwaves are increasing in frequency and can disrupt marine ecosystems non-linearly. In this study, we examined the effect of the North Pacific warming event of 2014, the largest long-term sea surface anomaly on record, on black-legged kittiwake Rissa tridactyla foraging trips before, during, and after the event. We assessed foraging trip characteristics (trip distance and duration), the dispersal of foraging locations, and the persistence of foraging areas within and among years. Foraging trip characteristics, foraging area size, and location varied from year to year. Kittiwake foraging was more dispersed, direct, and farther from the colony in years immediately after and during the warming event. A third of the foraging area used pre-heatwave (2012) was important in subsequent years, which indicates that this area was, and may still be, a perennial foraging hot spot. During the chick-rearing stage, black-legged kittiwakes increased their speed and reduced the proportion of resting compared to the incubation stage. We conclude that marine heatwaves may have a strong impact on seabird foraging, extending foraging ranges, and that those impacts may be nonlinear with a strong lag.

Schreiber E.A., Norton R.L.

Gallo N.D., Drenkard E., Thompson A.R., Weber E.D., Wilson-Vandenberg D., McClatchie S., Koslow J.A., Semmens B.X.

Multidisciplinary, integrated ocean observing programs provide critical data for monitoring the effects of climate change on marine ecosystems. California Cooperative Oceanic Fisheries Investigations (CalCOFI) samples along the US West Coast and is one of the world’s longest-running and most comprehensive time series, with hydrographic and biological data collected since 1949. The pairing of ecological and physical measurements across this long time series informs our understanding of how the California Current marine ecosystem responds to climate variability. By providing a baseline to monitor change, the CalCOFI time series serves as a Keeling Curve for the California Current. However, challenges remain in connecting the data collected from long-term monitoring programs with the needs of stakeholders concerned with climate change adaptation (i.e. resource managers, policy makers, and the public), including for the fisheries and aquaculture sectors. We use the CalCOFI program as a case study to ask: how can long-term ocean observing programs inform ecosystem based management efforts and create data flows that meet the needs of stakeholders working on climate change adaptation? Addressing this question and identifying solutions requires working across sectors and recognizing stakeholder needs. Lessons learned from CalCOFI can inform other regional monitoring programs around the world, including those done at a smaller scale in developing countries.

Sanford E., Sones J.L., García-Reyes M., Goddard J.H., Largier J.L.

During 2014–2016, severe marine heatwaves in the northeast Pacific triggered well-documented disturbances including mass mortalities, harmful algal blooms, and declines in subtidal kelp beds. However, less attention has been directed towards understanding how changes in sea surface temperature (SST) and alongshore currents during this period influenced the geographic distribution of coastal taxa. Here, we examine these effects in northern California, USA, with a focus on the region between Point Reyes and Point Arena. This region represents an important biogeographic transition zone that lies <150 km north of Monterey Bay, California, where numerous southern species have historically reached their northern (poleward) range limits. We report substantial changes in geographic distributions and/or abundances across a diverse suite of 67 southern species, including an unprecedented number of poleward range extensions (37) and striking increases in the recruitment of owl limpets (Lottia gigantea) and volcano barnacles (Tetraclita rubescens). These ecological responses likely arose through the combined effects of extreme SST, periods of anomalous poleward flow, and the unusually long duration of heatwave events. Prolonged marine heatwaves and enhanced poleward dispersal may play an important role in longer-term shifts in the composition of coastal communities in northern California and other biogeographic transition zones.

Auth T.D., Daly E.A., Brodeur R.D., Fisher J.L.

AbstractUnderstanding changes in the migratory and reproductive phenology of fish stocks in relation to climate change is critical for accurate ecosystem‐based fisheries management. Relocation and changes in timing of reproduction can have dramatic effects upon the success of fish populations and throughout the food web. During anomalously warm conditions (1–4°C above normal) in the northeast Pacific Ocean during 2015–2016, we documented shifts in timing and spawning location of several pelagic fish stocks based on larval fish samples. Total larval concentrations in the northern California Current (NCC) during winter (January–March) 2015 and 2016 were the highest observed since annual collections first occurred in 1998, primarily due to increased abundances of Engraulis mordax (northern anchovy) and Sardinops sagax (Pacific sardine) larvae, which are normally summer spawning species in this region. Sardinops sagax and Merluccius productus (Pacific hake) exhibited an unprecedented early and northward spawning expansion during 2015–16. In addition, spawning duration was greatly increased for E. mordax, as the presence of larvae was observed throughout the majority of 2015–16, indicating prolonged and nearly continuous spawning of adults throughout the warm period. Larvae from all three of these species have never before been collected in the NCC as early in the year. In addition, other southern species were collected in the NCC during this period. This suggests that the spawning phenology and distribution of several ecologically and commercially important fish species dramatically and rapidly changed in response to the warming conditions occurring in 2014–2016, and could be an indication of future conditions under projected climate change. Changes in spawning timing and poleward migration of fish populations due to warmer ocean conditions or global climate change will negatively impact areas that were historically dependent on these fish, and change the food web structure of the areas that the fish move into with unforeseen consequences.

Anderson D.W., Godínez-Reyes C.R., Velarde E., Avalos-Tellez R., Ramírez-Delgado D., Moreno-Prado H., Bowen T., Gress F., Trejo-Ventura J., Adrean L., Meltzer L.

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. 

Gentemann C.L., Fewings M.R., García-Reyes M.

From January 2014 to August 2016, sea-surface temperatures (SSTs) along the Washington, Oregon, and California coasts were significantly warmer than usual, reaching a maximum SST anomaly of 6.2 °C off southern California. This marine heat wave occurred alongside the Gulf of Alaska marine heat wave, and resulted in major disturbances in the California Current ecosystem and massive economic impacts. Here, we use satellite and blended reanalysis products to report the magnitude, extent, duration, and evolution of SSTs and wind stress anomalies along the west coast of the continental United States during this event. Nearshore SST anomalies along the entire coast were persistent during the marine heat wave, and only abated seasonally, during spring upwelling-favorable wind stress. The coastal marine heat wave weakened in July 2016 and disappeared by September 2016.

Cavole L., Demko A., Diner R., Giddings A., Koester I., Pagniello C., Paulsen M., Ramirez-Valdez A., Schwenck S., Yen N., Zill M., Franks P.

Velarde E., Ezcurra E., Horn M.H., Patton R.T.

Since 2000, Elegant Terns have begun migrating northward in the face of warm oceanographic anomalies.

Auer S.K., King D.I.

Aim Species are expected to move uphill or poleward in response to climate change, yet their distributions show idiosyncratic responses; many species are moving in the predicted direction, but others are not shifting at all or are shifting downhill or towards the equator. Fundamental questions remain about the causes of interspecific variation in range responses and whether shifts along elevational and latitudinal gradients are correlated. We examined whether shifts in northernlatitude and upper-elevation boundaries of western North American songbirds over a 35-year period were correlated and whether species ecological and lifehistory traits explained interspecific variation in observed shifts.

Velarde E., Ezcurra E., Anderson D.W.

Small pelagic fisheries show wide fluctuations, generally attributed to oceanographic anomalies. Most data on these fisheries come from landings, often reporting sustained catches-per-unit-effort (CPUEs) until a decline occurs. Fishery-independent data are important as management tools. In this study we show that the proportions of Pacific Sardine and Northern Anchovy in the diet of three seabird species (California Brown Pelicans, Heermann's Gulls and Elegant Terns) nesting in spring in the Gulf of California show significant relationships with CPUEs during the following season in gulls and terns, or during the same season in pelicans. As sardine availability for seabirds declines, CPUEs remain high until the fishery falls, one or two seasons later. A declining proportion of sardines in the seabirds' diet, combined with the status of the Pacific warm-phase anomaly (El Niño), give a reliable forecast of diminishing CPUEs and signals the need to reduce fishing efforts in the ensuing season.

Peterson A.T., Ortega-Huerta M.A., Bartley J., Sánchez-Cordero V., Soberón J., Buddemeier R.H., Stockwell D.R.

Global climates are changing rapidly, with unexpected consequences1. Because elements of biodiversity respond intimately to climate as an important driving force of distributional limitation2, distributional shifts and biodiversity losses are expected3,4. Nevertheless, in spite of modelling efforts focused on single species2 or entire ecosystems5, a few preliminary surveys of fauna-wide effects6,7, and evidence of climate change-mediated shifts in several species8,9, the likely effects of climate change on species' distributions remain little known, and fauna-wide or community-level effects are almost completely unexplored6. Here, using a genetic algorithm and museum specimen occurrence data, we develop ecological niche models for 1,870 species occurring in Mexico and project them onto two climate surfaces modelled for 2055. Although extinctions and drastic range reductions are predicted to be relatively few, species turnover in some local communities is predicted to be high (>40% of species), suggesting that severe ecological perturbations may result.

Russell T.M., Pereksta D.M., Tietz J.R., Vernet M., Jahncke J., Ballance L.T.

ABSTRACTClimate change is impacting marine ecosystems in the California Current Ecosystem (CCE) through physical changes (e.g., an increase in the frequency and intensity of marine heatwaves) that manifest biologically at all trophic levels. We investigated range expansion into the CCE and correlations with environment for a group of tropical/sub-tropical seabirds. We assessed changes in the abundance (2002-2022) of five species from the genus,Sula(Cocos, Blue-footed, Red-footed, Masked, and Nazca Boobies), using a novel compilation of four data sources (at-sea surveys, n=82 observations, records from Southeast Farallon Island, n=600, the California Rare Birds Committee, n=593, andeBird-a citizen science mobile application, n= 20,529), and looked for relationships with the environment, including broad temporal and spatial scale dynamics (El Niño Southern Oscillation), local conditions where the bird was reported, and potential source conditions from Baja California Sur and the Gulf of California. All five species increased in abundance, and all, with the exception of Blue-footed, exhibited a northward range expansion by as much as 6.8 degrees latitude and increased range area of between 235-1013% within the CCE. There was increased abundance during warmer conditions (El Niño and warm SST) for Cocos, Red-footed, Masked, and Nazca Boobies, and all species increased by 692-3015% after the extreme marine heatwaves that began in late 2013. Our results document a tropical shift in seabirds of the CCE, which may present future challenges to resident species. As marine heatwaves are projected to increase in frequency and intensity, in addition to long-term warming, we hypothesize that these species will continue to expand their range northward in the CCE.