skip to main content

Title: Successful Long-Distance Breeding Range Expansion of a Top Marine Predator
Little is known about the effects of large-scale breeding range expansions on the ecology of top marine predators. We examined the effects of a recent range expansion on the breeding and foraging ecology of Laysan albatrosses ( Phoebastria immutabilis ). Laysan albatrosses expanded from historical breeding colonies in the Central Pacific Ocean to the Eastern Pacific Ocean around central Baja California, Mexico, leading to a 4,000-km shift from colonies located adjacent to the productive transition zone in the Central Pacific to colonies embedded within the eastern boundary current upwelling system of the Eastern Pacific California Current. We use electronic tagging and remote sensing data to examine the consequences of this range expansion on at-sea distribution, habitat use, foraging habitat characteristics, and foraging behavior at sea by comparing birds from historic and nascent colonies. We found the expansion resulted in distinct at-sea segregation and differential access to novel oceanographic habitats. Birds from the new Eastern Pacific colony on Guadalupe Island, Mexico have reduced ranges, foraging trip lengths and durations, and spend more time on the water compared to birds breeding in the Central Pacific on Tern Island, United States. Impacts of the range expansion to the post-breeding season were less pronounced more » where birds maintained some at-sea segregation but utilized similar habitat and environmental variables. These differences have likely benefited the Eastern Pacific colony which has significantly greater reproductive output and population growth rates. Laysan albatrosses have the plasticity to adapt to distinctly different oceanographic habitats and also provide insight on the potential consequences of range shifts to marine organisms. « less
Authors:
; ; ; ; ; ; ; ; ;
Award ID(s):
2049303
Publication Date:
NSF-PAR ID:
10326872
Journal Name:
Frontiers in Ecology and Evolution
Volume:
9
ISSN:
2296-701X
Sponsoring Org:
National Science Foundation
More Like this
  1. Elegant terns Thalasseus elegans breed in a very limited area of the northern Gulf of California and the Pacific coast of southern California, with up to 95% (mean 78%, 1991–2014, Perez et al., 2020 ) of the population nesting on Isla Rasa in the northern Gulf of California. On Isla Rasa, the primary nesting colony, elegant terns suffered predation by rodents which raised the possibility of population extinction, with a substantial proportion of the world population nesting on this single island. Because of this threat, rodents were successfully removed from Isla Rasa in 1995. The removal of rodents from Isla Rasa led to a near immediate increase in the population of elegant terns. That increase was associated with a changing pattern in dispersal by the terns, including extraordinary movements to the Gulf of Mexico, the Atlantic coast of the United States north to Massachusetts, and, remarkably, to western Europe. A few elegant terns successfully bred at these European localities during 2009 to the present. In this paper we use this exceptional example of long-distance dispersal to illustrate how rapid population growth during ∼ 1995 to present can lead to successful colonization of remote sites through repeated instances of vagrancy. Wemore »tested four Hypotheses that together support the idea that the growing population of elegant terns has produced increasing numbers of young, and these young have spread, through the mechanism of vagrancy, to the Pacific Northwest, the east coast of the United States, and western Europe. Our Hypotheses are: (1) The nesting population of elegant terns within their core nesting range has increased since removal of rodents from Isla Rasa; (2) Occurrence of vagrant elegant terns in the Pacific Northwest is driven by population growth within the core breeding range. (3) Occurrence of vagrant elegant terns at the east coast of the United States is driven by population growth within the core breeding range. (4) Occurrence and colonization of western Europe by elegant terns is driven by nesting population size within the core breeding range. Corollaries of these Hypotheses are, (i) that there is a time lag in occurrence of vagrants at each of these areas, based on increasing distance from the core breeding range and (ii) the number of vagrants in any given year is also related to sea surface temperature (SST), as expressed by Oceanic Niño Index, a proxy for food resource levels. Generally we found strong statistical support for each of these Hypotheses; an exception was for the occurrence of elegant terns in the Pacific Northwest, which initially occurred following El Niño events (low food supply) and profound breeding failure, but later corresponding to cold water years with high breeding success. We use elegant terns, exceptional for the highly restricted breeding range and sustained population growth over 25 years, to illustrate how growing populations may colonize very distant habitats through repeated instances of vagrancy.« less
  2. The Antarctic Circumpolar Current (ACC) is the world’s strongest zonal current system that connects all three major ocean basins of the global ocean and therefore integrates and responds to global climate variability. Its flow is largely driven by strong westerly winds and constricted to its narrowest extent in the Drake Passage. Transport of fresh and cold surface and intermediate water masses through the Drake Passage (cold-water route) strongly affects the Atlantic Meridional Overturning Circulation together with the inflow of Indian Ocean water masses (warm-water route). Both oceanographic corridors are critical for the South Atlantic contribution to Meridional Overturning Circulation changes. In contrast to the Atlantic and Indian sectors of the ACC, and with the exception of drill cores from the Antarctic continental margin and off New Zealand, the Pacific sector of the ACC lacks information on its Cenozoic paleoceanography from deep-sea drilling records. To advance our knowledge and understanding of Miocene to Holocene atmosphere-ocean-cryosphere dynamics in the Pacific and their implications for regional and global climate and atmospheric CO2, International Ocean Discovery Program (IODP) Expedition 383 recovered sedimentary sequences at (1) three sites located in the central South Pacific (U1539, U1540, and U1541), (2) two sites at the Chile marginmore »(U1542 and U1544), and (3) one site from the pelagic eastern South Pacific (U1543) close to the entrance to the Drake Passage. Because of persistently stormy conditions and the resulting bad weather avoidance, we were not successful in recovering the originally planned Proposed Site CSP-3A in the central South Pacific in the Polar Frontal Zone. The drilled sediments at Sites U1541 and U1543 reach back to the late Miocene, and those at Site U1540 reach back to the early Pliocene. High sedimentary rate Pleistocene sedimentary sequences were drilled both in the central South Pacific (Site U1539) and along the Chile margin. Taken together, the sites represent a depth transect from ~1100 m at the Chile margin site (U1542) to ~4070 m in the central South Pacific (Site U1539) and allow investigation of changes in the vertical structure of the ACC, a key issue for understanding the role of the Southern Ocean in the global carbon cycle. The sites are located at latitudes and water depths where sediments will allow the application of a wide range of siliciclastic-, carbonate-, and opal-based proxies to address our objectives of reconstructing with unprecedented stratigraphic detail surface to deep-ocean variations and their relation to atmosphere and cryosphere changes through stadial to interstadial, glacial to interglacial, and warmer than present time intervals.« less
  3. Abstract Group-size variation is common in colonially breeding species, including seabirds, whose breeding colonies can vary in size by several orders of magnitude. Seabirds are some of the most threatened marine taxa and understanding the drivers of colony size variation is more important than ever. Reproductive success is an important demographic parameter that can impact colony size, and it varies in association with a number of factors, including nesting habitat quality. Within colonies, seabirds often aggregate into distinct groups or subcolonies that may vary in quality. We used data from two colonies of Adélie penguins 73 km apart on Ross Island, Antarctica, one large and one small to investigate (1) How subcolony habitat characteristics influence reproductive success and (2) How these relationships differ at a small (Cape Royds) and large (Cape Crozier) colony with different terrain characteristics. Subcolonies were characterized using terrain attributes (elevation, slope aspect, slope steepness, wind shelter, flow accumulation), as well group characteristics (area/size, perimeter-to-area ratio, and proximity to nest predators). Reproductive success was higher and less variable at the larger colony while subcolony characteristics explained more of the variance in reproductive success at the small colony. The most important variable influencing subcolony quality at both colonies wasmore »perimeter-to-area ratio, likely reflecting the importance of nest predation by south polar skuas along subcolony edges. The small colony contained a higher proportion of edge nests thus higher potential impact from skua nest predation. Stochastic environmental events may facilitate smaller colonies becoming “trapped” by nest predation: a rapid decline in the number of breeding individuals may increase the proportion of edge nests, leading to higher relative nest predation and hindering population recovery. Several terrain covariates were retained in the final models but which variables, the shapes of the relationships, and importance varied between colonies.« less
  4. The ecology of an epibiont may depend not only on the dynamics of its biogenic habitat but also on microclimate variation generated within aggregations of its host, a process called physical ecosystem engineering. This study explored variation in the abundance and demography of Membranipora, a suspension-feeding bryozoan, within forests of giant kelp (Macrocystis pyrifera) off the coast of Santa Barbara, California, USA. First, we assessed differences in Membranipora abundance between the edge and interior of kelp forests. The occurrence of Membranipora on kelp blades and its percent cover on occupied blades were higher along forest edges than interiors. Second, we conducted observational studies and field experiments to understand spatial variation in substrate longevity, colony mortality, larval recruitment, and colony growth rates. A higher density of recruits and colonies occurred along forest edges than interiors, suggesting kelp acts like a sieve, whereby larvae settle to edge blades first. Moreover, growth rates along the edge were up to 45% higher than forest interiors. Reduced current speeds, combined with feeding by exterior colonies, may have lowered the uptake of suspended food particles by interior colonies. These results suggest that variation in Membranipora abundance is due in part to differences in colony growth betweenmore »forest edges and interiors, and not solely the result of recruitment limitation. Our results highlight the importance of ecosystem engineers in influencing the ecological dynamics of epiphytic flora and fauna in marine systems.« less
  5. Climate change is a threat to marine turtles that is expected to affect all of their life stages. To guide future research, we conducted a review of the most recent literature on this topic, highlighting knowledge gains and research gaps since a similar previous review in 2009. Most research has been focused on the terrestrial life history phase, where expected impacts will range from habitat loss and decreased reproductive success to feminization of populations, but changes in reproductive periodicity, shifts in latitudinal ranges, and changes in foraging success are all expected in the marine life history phase. Models have been proposed to improve estimates of primary sex ratios, while technological advances promise a better understanding of how climate can influence different life stages and habitats. We suggest a number of research priorities for an improved understanding of how climate change may impact marine turtles, including: improved estimates of primary sex ratios, assessments of the implications of female-biased sex ratios and reduced male production, assessments of the variability in upper thermal limits of clutches, models of beach sediment movement under sea level rise, and assessments of impacts on foraging grounds. Lastly, we suggest that it is not yet possible to recommendmore »manipulating aspects of turtle nesting ecology, as the evidence base with which to understand the results of such interventions is not robust enough, but that strategies for mitigation of stressors should be helpful, providing they consider the synergistic effects of climate change and other anthropogenic-induced threats to marine turtles, and focus on increasing resilience.« less