Article

Climate, copepods and seabirds in the boreal Northeast Atlantic - current state and future outlook

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Abstract

The boreal Northeast Atlantic is strongly affected by current climate change, and large shifts in abundance and distribution of many organisms have been observed, including the dominant copepod Calanus finmarchicus, which supports the grazing food web and thus many fish populations. At the same time, large-scale declines have been observed in many piscivorous seabirds, which depend on abundant small pelagic fish. Here, we combine predictions from a niche model of C. finmarchicus with long-term data on seabird breeding success to link trophic levels. The niche model shows that environmental suitability for C. finmarchicus has declined in southern areas with large breeding seabird populations (e.g. the North Sea), and predicts that this decline is likely to spread northwards during the 21st century to affect populations in Iceland and the Faroes. In a North Sea colony, breeding success of three common piscivorous seabird species [black-legged kittiwake (Rissa tridactyla), common guillemot (Uria aalge) and Atlantic puffin (Fratercula arctica)] was strongly positively correlated with local environmental suitability for C. finmarchicus, whereas this was not the case at a more northerly colony in west Norway. Large seabird populations seem only to occur where C. finmarchicus is abundant, and northward distributional shifts of common boreal seabirds are therefore expected over the coming decades. Whether or not population size can be maintained depends on the dispersal ability and inclination of these colonial breeders, and on the carrying capacity of more northerly areas in a warmer climate.

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... In UK waters, cod and sand eel stocks have particularly suffered overexploitation. The latter case has had serious impacts on seabird populations (Frederiksen et al. 2013) -with the impact being compounded by the synergy of sand eel overfishing and the range shift of the copepod Calanus finmarchicus, a main food species of sand eel (see Seabird section below). In the case of cod, the combination of intense fishing pressure and climate change (discussed above) has led to a northward shift of distribution ranges (Engelhard et al. 2014). ...
... Major changes are expected for the UK's seabird fauna. The puffin (Fratercula arctica), tourist magnets e.g. of the Shetland Islands for example, has been declining in the UK and beyond (Frederiksen et al. 2013). This is strongly correlated with the climate-related decline of a major copepod species, Calanus finnmarchicus constituting the basis of the food web that puffins and other seabird species rely on (Frederiksen et al. 2013). ...
... The puffin (Fratercula arctica), tourist magnets e.g. of the Shetland Islands for example, has been declining in the UK and beyond (Frederiksen et al. 2013). This is strongly correlated with the climate-related decline of a major copepod species, Calanus finnmarchicus constituting the basis of the food web that puffins and other seabird species rely on (Frederiksen et al. 2013). Conversely, the little egret (Egretta garzetta), not recorded as a breeding bird until 1997 and considered a species with warm-temperate affinities, has recently strongly expanded its range into the UK (Wood andStillman 2014, MCCIP 2015). ...
Article
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Marine biodiversity and ecosystem functioning – including seaweed communities – in the territorial waters of the UK and its Overseas Territories are facing unprecedented pressures. Key stressors are changes in ecosystem functioning due to biodiversity loss caused by ocean warming (species replacement and migration, e.g. affecting kelp forests), sea level rise (e.g. loss of habitats including salt marshes), plastic pollution (e.g. entanglement and ingestion), alien species with increasing numbers of alien seaweeds (e.g. outcompeting native species and parasite transmission), overexploitation (e.g. loss of energy supply further up the food web), habitat destruction (e.g. loss of nursery areas for commercially important species) and ocean acidification (e.g. skeletal weakening of ecosystem engineers including coralline algal beds). These stressors are currently affecting biodiversity, and their impact can be projected for the future. All stressors may act alone or in synergy. Marine biodiversity provides crucial goods and services. Climate change and biodiversity loss pose new challenges for legislation. In particular, there are implications of climate change for the designation and management of Marine Protected Areas and natural carbon storage by marine systems to help control the global climate system. The UK currently has legal obligations to protect biodiversity under international and European law.
... If C. finmarchicus is not replaced by other zooplankton suitable as prey for small fish, seabird populations are likely to experience reduced breeding success, leading to further declines in population size (Frederiksen et al. 2013). Indeed, a close relative of C. finmarchicus, the warm-temperate C. helgolandicus has increased in abundance in the North Sea over recent decades as C. finmarchicus abundance has declined . ...
... There are several reasons for this: C. helgolandicus are smaller, have a lower lipid content, and tend to occur at low densities early in spring when most fish larvae need access to abundant copepod prey . Frederiksen et al. (2013) anticipated that because of these shifts in the zooplankton community resulting in declines in abundance of fish such as sandeel and the lack of obvious replacements for these as seabird prey, it is likely that breeding populations of piscivorous seabirds in the boreal Northeast Atlantic, including the North Sea will shift northwards. Consequently, the large seabird populations currently present in, for example, eastern Scotland could disappear (Frederiksen et al. 2013). ...
... Frederiksen et al. (2013) anticipated that because of these shifts in the zooplankton community resulting in declines in abundance of fish such as sandeel and the lack of obvious replacements for these as seabird prey, it is likely that breeding populations of piscivorous seabirds in the boreal Northeast Atlantic, including the North Sea will shift northwards. Consequently, the large seabird populations currently present in, for example, eastern Scotland could disappear (Frederiksen et al. 2013). ...
Chapter
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This chapter presents a review of what is known about the impacts of climate change on the biota (plankton, benthos, fish, seabirds and marine mammals) of the North Sea. Examples show how the changing North Sea environment is affecting biological processes and organisation at all scales, including the physiology, reproduction, growth, survival, behaviour and transport of individuals; the distribution, dynamics and evolution of populations; and the trophic structure and coupling of ecosystems. These complex responses can be detected because there are detailed long-term biological and environmental records for the North Sea; written records go back 500 years and archaeological records many thousands of years. The information presented here shows that the composition and productivity of the North Sea marine ecosystem is clearly affected by climate change and that this will have consequences for sustainable levels of harvesting and other ecosystem services in the future. Multi-variate ocean climate indicators that can be used to monitor and warn of changes in composition and productivity are now being developed for the North Sea.
... Carroll et al. (2015) showed that kittiwake breeding success is predicted to decline by 21-43% between 1961−90 and 2070−99. Frederiksen et al. (2013) predicted that habitat suitability for seabirds will shift northward over the next century, and concluded that northern distributional shifts of seabirds are likely over this period. Russell et al. (2015b) used climate envelope models together with climate scenarios to predict that 65% of species that breed in the British Isles would show a decline in their European range, some by as much as 80%. ...
... In addition to effects of warming, the last decade has seen a growing realisation of the importance of extreme weather events, which may have a profound impact on seabird populations by reducing both breeding performance and survival rates of immature and adult birds Newell et al., 2015). Furthermore, studies are, for the first time, projecting future population change and are predicting substantial changes in the range and population sizes of seabirds in the UK, including some species for which the UK holds internationally important numbers such as great skua and arctic skua (Huntley et al., 2007;Frederiksen et al., 2013;Carroll et al., 2015;Russell et al., 2015b). This shift in emphasis towards future forecasting is of fundamental importance to developing effective conservation strategies for these species, in keeping with the drive to take a spatio-temporally dynamic approach to species conservation and habitat protection. ...
... Many seabirds are at the limit of their breeding range in the UK, and models of habitat suitability under scenarios of climate warming suggest there will be a retraction to more northern parts of the UK and overall changes in population size (Huntley et al., 2007). Northward shifts of the principal prey of seabirds, sandeels, are also expected due to movements of critical thermal boundaries (Frederiksen et al., 2013). Trophic mismatch may also increase, with the potential for negative consequences on seabirds if they become desynchronised with their prey (Burthe et al., 2002). ...
... C. finmarchicus is a boreal species with the southern limits of its range in the North Sea and a SST thermal optimum of 4.5 -8.5°C, above or below which occurrence becomes rapidly reduced (Reygondeau and Beaugrand, 2010). Since the 1960s the biomass of C. finmarchicus in the North Sea has declined by 70% (Macdonald, et al., 2015), coincident with a decline in climatic suitability (Frederiksen et al., 2013). In contrast, there has been a gradual increase in abundance of the pseudo-oceanic temperate species C. helgolandicus since the mid-1980s (Jaschnov, 1970;Beaugrand et al., 2002;Beaugrand et al., 2003). ...
... Further, the maximum potential duration of diapause (a period of reduced metabolic activity in response to low food availability during the winter) is likely to decline with increasing overwinter temperature, as metabolic costs increase with temperature and therefore the lipid reserves upon which the copepods rely are used up at a greater rate (Wilson et al., 2016b). In addition to observed declines in climatic suitability around east Scotland and southern Iceland, further declines are expected to occur in Norway and the Faroes by the mid-late 21 st century (Frederiksen et al., 2013). Thus declines in the abundance of this copepod in the North Sea are projected to continue and expand (Frederiksen et al., 2013). ...
... In addition to observed declines in climatic suitability around east Scotland and southern Iceland, further declines are expected to occur in Norway and the Faroes by the mid-late 21 st century (Frederiksen et al., 2013). Thus declines in the abundance of this copepod in the North Sea are projected to continue and expand (Frederiksen et al., 2013). ...
Technical Report
Full-text available
Technical report by the RSPB on the lesser sandeel, Ammodytes marinus, including a review of its ecology, population trends and importance in the food chain, causes of spatial and temporal variation, and threats to the species including climate change.
... All of these challenges, which also compromise many other components of marine biodiversity, have to be urgently addressed. Most of the studies dealing with climate change impacts on seabirds focus on population processes or on their responses during the breeding season (Frederiksen, Anker-Nilssen, Beaugrand, & Wanless, 2013). Indeed, seabirds are easily reachable on land during this period, and as most of them are philopatric (Schreiber & Burger, 2002), they can be monitored year after year at the same colony. ...
... They are around 6-7 million breeding pairs of Atlantic puffins in total, with some declines among European colonies in the last decades . Determining the causes of such declines is difficult but environmental conditions could impact Atlantic puffins breeding success through direct or indirect effects: For example it is negatively correlated to sea surface temperature (Kress, Shannon, & O'Neal, 2016) and positively correlated to Calanus finmarchicus habitat suitability (Frederiksen et al., 2013). ...
... Yet, because of technological limitations and practical difficulties, most of these studies dealing with climate change impacts on seabirds focus on population processes or on their responses during breeding season (Frederiksen, Anker-Nilssen, Beaugrand, & Wanless, 2013), rather than climate change impacts on their at-sea distributions during the non-breeding period. This is critical since conditions encountered during the non-breeding period strongly shape seabird population dynamics . ...
Thesis
Seabirds are particularly vulnerable to the direct and indirect effects of climate change, however little is known about those impacts outside of the breeding season. This lack of knowledge is problematic because the conditions encountered during migration and wintering strongly shape seabird population dynamics. It is therefore essential to understand the effects of climate on their winter distribution and migration routes. Linking the distribution of organisms to environmental factors is therefore a primary task benefiting from the concept of energyscapes (defined as the variation of an organism's energy requirements across space according to environmental conditions) which has recently provided a mechanistic explanation for the distribution of many animals. In this context, we have predicted the current and future winter habitats of five species representing 75% of the seabird community in the North Atlantic (Alle alle, Fratercula arctica, Uria aalge, Uria lomvia and Rissa tridactyla). To this aim, we monitored the movements of more than 1500 individuals to identify the birds' preferred habitats through resource selection functions based on the modeling of their energy expenditure and prey availability. Electronic tracking data were also overlaid with cyclone locations to map areas of high exposure for the seabird community across the North Atlantic. In addition, we explored the energetic consequences of seabird exposure to storms using a mechanistic bioenergetic model (Niche MapperTM). Finally, we examined the impact of total summer sea ice melt from 2050 on Arctic bird migration. Our analyses predict a northward shift in the preferred wintering areas of the North Atlantic seabird community, especially if global warming exceeds 2°C. Our results suggest that cyclonic conditions do not increase the energy requirements of seabirds, implying that they die from the unavailability of prey and/or inability to feed during cyclones. Finally, the melting sea ice at the North Pole may soon allow 29 species of Arctic birds to make new trans-Arctic migrations between the Atlantic and the Pacific. We also estimate that an additional 26 currently migratory species could remain in the Arctic year-round. This work illustrates how climate change could radically alter the biogeography of migratory species and we provide a methodological toolbox to assess and predict these changes by combining movement ecology and energetic physiology.
... However, population modelling of the Flamborough and Filey Coast pSPA kittiwake population (MacArthur Green 2015a) indicated that an annual mortality of 372 adults would reduce the median population growth rate by approximately 0.5%. A reduction of this magnitude would be difficult to measure from census data, especially against a background where impacts on population growth are anticipated as a consequence of climate change (Frederiksen et al. 2013). 134. ...
... Birds that are short of food or short of time to search for food may be more willing to enter areas they perceive as risky. There is evidence for changing diet composition ) and foraging conditions (Frederiksen et al. 2013) for common guillemots (and other seabirds) in the North Sea which could alter their behavioural responses to offshore wind farms even in the absence of any habituation. ...
Technical Report
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The aim of this literature review is to inform the understanding of the current state of knowledge of selected seabird species (northern gannet Morus bassanus hereafter ‘gannet’, black-legged kittiwake Rissa tridactyla hereafter ‘kittiwake’, lesser black-backed gull Larus fuscus, great black-backed gull L. marinus, common guillemot (=common murre) Uria aalge, razorbill Alca torda, and red-throated diver Gavia stellata), and to identify key knowledge gaps in terms of assessing impacts of offshore wind farms for these seabird species and specifically for their populations in the southern North Sea.
... Poloczanska et al. 2013). For instance, in the North Sea, climate-related changes in abundance and distribution of the copepod Calanus finmarchicus, an important food source for small forage fish, was found to negatively affect breeding success of 3 common piscivorous seabirds (Frederiksen et al. 2013). This was not the case for a colony situated farther north in the Norwegian Sea, suggesting that the predicted northwards decline in copepod abundance might only have influenced the southernmost colonies so far (Frederiksen et al. 2013). ...
... For instance, in the North Sea, climate-related changes in abundance and distribution of the copepod Calanus finmarchicus, an important food source for small forage fish, was found to negatively affect breeding success of 3 common piscivorous seabirds (Frederiksen et al. 2013). This was not the case for a colony situated farther north in the Norwegian Sea, suggesting that the predicted northwards decline in copepod abundance might only have influenced the southernmost colonies so far (Frederiksen et al. 2013). ...
Article
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Seabird populations have declined worldwide, and several of the potential threats are of anthropogenic origin. To understand how changes in seabird populations relate to environmental conditions it is important to know the functional relationships between prey availability and foraging behaviour, prey choice and breeding performance over several years. This was studied by linking breeding success of European shag Phalacrocorax aristotelis to variation in diet composition, and investigating the underlaying mechanism driving this variation, primarily based on be - havioural costs associated with foraging, such as foraging range and diving effort. We obtained demographic data and foraging trip metrics (using GPS-loggers and time−depth recorders) from a shag colony at Sklinna, Central Norway, during the 2011−2016 breeding seasons. Breeding population size was closely and positively correlated with breeding success, which in turn was positively correlated with the proportion of saithe Pollachius virens in the diet. When the dietary proportion of uncommon prey species increased, breeding success decreased. Breeding success was negatively influenced by increasing distance travelled and accumulated dive depths on an annual basis. Summed dive depths were greatest when prey species other than saithe dominated the diet. We found that in years with low availability of saithe fewer shags bred, and those that did had lower breeding success. This indicates that in years with poor feeding conditions, there might not be sufficient resources in the foraging area to support the whole breeding population of shags.
... The GOM has undergone at least 3 climate-driven regime shifts since the 1980s from a combination of local atmospheric warming and remote forcing from the rapidly warming Arctic Ocean (Greene et al. 2013). Concurrent northward movement of the Gulf Stream has caused widespread warming in the northeast Atlantic, with dramatic effects on seabirds there including reduced breeding success (Foster & Marrs 2012, Frederiksen et al. 2013, Miles et al. 2015. The changes in alcid diet we document here are best discussed in this context and suggest similar changes may be beginning in the northwest Atlantic. ...
... Many right whales formerly spent summers feeding on these copepods in the Bay of Fundy, but since 2011 have largely abandoned it and moved north (Pace et al. 2017). Linkages between declines of C. finmarchicus and seabirds have also been identified in the northeast Atlantic (Frederiksen et al. 2013). ...
Preprint
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This paper examines responses of three alcids breeding in the Bay of Fundy/Gulf of Maine to changes in diet over ~20 years of collecting chick diet data on three colonies including Machias Seal Island (MSI). Atlantic puffins had the most varied diet and were most vulnerable to increases in SST, especially warm winters followed by a warm summer which caused breeding success <20%. Each species responded differently to changing prey base.Prey declined in quality around 2000, when herring almost disappeared from the diet, and again after 2010 when haddock and other gadids became prominent in puffin diet. Fat content did not drive responses directly. Acadian redfish have replaced herring in southern colonies but not at MSI.
... While a positive link was found between copepod biomass in Eastern Scotland, the abundance of sandeel larvae and kittiwake breeding productivity on the Isle of May (Scott et al. 2006), this relationship did not hold in another colony in East Scotland (Fowlsheugh SPA), across North Sea regions (Frederiksen et al. 2007) or in the North-East Atlantic (Lauria et al. 2013). Moreover, no consistent patterns emerged from looking at the relationship between kittiwake productivity and previous year's abundance of copepods within North Atlantic regions (Frederiksen et al. 2013(Frederiksen et al. , 2007. ...
... The strength of marine trophic relationships is expected to vary both in space, due to differing physical and biological mechanisms operating at the scale of a colony vs. regional population, and in time due to the predicted species distribution range shifts as SST increases (e.g. Frederiksen et al. 2013). Furthermore, changes in oceanographic conditions can affect seabirds at both their breeding and nonbreeding foraging areas, with potential lag effects of a decline in immature survival during the autumn and winter months on population growth rates (e.g. ...
Technical Report
Full-text available
Offshore windfarms are seen as a key part of efforts to combat climate change. However, there are a number of significant concerns about the potential of these windfarms to have a negative impact on wildlife and biodiversity, particularly in relation to birds. This is of particular concern as the scale of offshore windfarm development expands so that the risk of reaching unacceptable levels of cumulative impacts also increases. This work has been undertaken on behalf of the Offshore Wind Strategic Monitoring and Research Forum (OWSMRF). The report presents a summary of existing evidence, and potential research opportunities, to better understand the population dynamics of black-legged kittiwakes and how their populations might respond to potential additional mortality from offshore windfarm development and conservation management measures. The intention is that this report provides a signpost towards research that can facilitate meaningful and precise cumulative impact assessments, and thus contribute to reducing uncertainty in decision making around offshore windfarm consenting in the next few years. Full report can be found here: https://hub.jncc.gov.uk/assets/c563bfa5-8177-4dc0-bcb3-4aeafef24b59
... As suggested by Gaston et al. (2005a), we expect that continued global warming may benefit murres at PLI in the short term, as the availability of open water during the early breeding season in the high Arctic increases. At the same time, climate amelioration may result in an eventual northward displacement of populations from farther south (Frederiksen et al. 2013;Boertmann et al. 2020;Patterson et al. 2021). The steady growth we report in the murre breeding population at PLI since 1975 does not appear to be related to ice given the lack of consistent directional change in ice conditions around the colony, and warrants further study to determine its cause. ...
... As the distribution of both seabirds and their prey shift with future ice changes, it is essential to understand how species use MPAs both now and under future climate conditions (Davies et al. 2017). As ocean temperatures continue to increase, seabird distributions are projected to shift northward (Frederiksen et al. 2013;Boertmann et al. 2020;Patterson et al. 2021). This highlights the importance of MPAs such as Tallurutiup Imanga that protect northern areas, but also long-term monitoring studies like ours that can inform future MPA networks (Carr et al. 2017). ...
Article
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Seabirds breeding in the high Arctic contend with variable annual sea ice conditions, with important consequences depending on a species’ unique reproductive and foraging ecology. We assessed the influence of sea ice extent and phenology on seabird breeding biology using monitoring data collected for northern fulmar (Fulmarus glacialis), glaucous gull (Larus hyperboreus), black-legged kittiwake (Rissa tridactyla), and thick-billed murre (Uria lomvia) breeding at Prince Leopold Island, Nunavut, Canada over 4 decades. We expected that years of later sea ice break-up and greater ice cover around the colony would create greater challenges to foraging and could result in delayed nest initiation, decreased colony attendance, and lower nesting success, but with distinct responses from each species. We also tested for time-lagged effects of ice conditions, where sea ice in a given year could impact food availability or juvenile recruitment in later years. Ice conditions around the colony exhibited no significant overall temporal trends or changepoints over the past 50 years (1970–2021), while counts of kittiwakes and murres increased over the study period 1975–2013. No trends were evident in counts of fulmars or gulls or in egg-laying dates or nest success for any species. However, three species (all but glaucous gulls) exhibited unique responses between breeding metrics and sea ice, highlighting how breeding decisions and outcomes may differ among species under the same environmental conditions in a given year. Time-lagged effects were only detected for kittiwake nest counts, where the date of spring ice break-up around the colony was negatively associated with counts at a 5-year lag. Greater distances to open water were associated with lower colony attendance by fulmars and later nest initiation by kittiwakes and murres. Our analyses provide additional insights to effects of sea ice on high-Arctic seabird breeding ecology, which will be useful in predicting and planning for the complex effects of a changing climate and changing human pressures on this high-latitude ecosystem and for the management of high-Arctic marine-protected areas.
... Critical new evidence suggests that the proportion of sandeels in the diet of seabirds breeding on the Isle of May National Nature Reserve, south-east Scotland, has declined in both summer and winter over the last three decades, linked to trends in SST (Howells et al., 2017(Howells et al., , 2018Wanless et al., 2018). Warming of waters around much of the UK has led to substantial changes in species composition and abundance at lower trophic levels Kirby and Beaugrand 2009;Luczak et al., 2012;Frederiksen et al., 2013). There have been northward shifts of key copepod prey of sandeels, associated with critical thermal boundaries Reygondeau and Beaugrand 2011). ...
... As a result, we may see changes in species' ranges in association with climate change, with the potential for associated overall declines in population size. Frederiksen et al. (2013) and Russell et al. (2015) predicted that habitat suitability for seabirds will shift northward over the next century, and concluded that northern distributional shifts of seabirds are likely over this period. Russell et al. (2015) constructed climate envelopes for each species, which characterised the climate of their range using a composite of measures of (a) winter cold, (b) overall warmth or growing season, and (c) available moisture. ...
Chapter
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EXECUTIVE SUMMARY • The seabird declines that commenced at the end of the last century have continued during the last two decades. • Further research into the causes of these declines is required if we are to fully understand the complex mechanisms operating, which are known to vary geographically. Climate change is considered to be one of the main causes of the declines. The principal mechanism is the effect of climate warming on food supply. • There is growing evidence that short-term weather conditions have an important effect, including extreme weather events. Climate models predict further warming and increased severity and frequency of extreme weather events in UK waters. • Seabirds face an uncertain future and may decline further in the coming decades, as the interacting effects of new and existing influences will pose additional challenges.
... How these changes will affect higher trophic levels remains unclear. However, it is thought that the retreat of Calanus finmarchicus will be damaging to sandeel populations (van Deurs et al. 2009) and, ultimately, seabirds (Frederiksen et al. 2013). A recent niche model study (Frederiksen et al. 2013) showed that the breeding success of kittiwakes and Atlantic puffins on the Isle of May is significantly related to environmental suitability for C. finmarchicus (van Deurs et al. 2009). ...
... However, it is thought that the retreat of Calanus finmarchicus will be damaging to sandeel populations (van Deurs et al. 2009) and, ultimately, seabirds (Frederiksen et al. 2013). A recent niche model study (Frederiksen et al. 2013) showed that the breeding success of kittiwakes and Atlantic puffins on the Isle of May is significantly related to environmental suitability for C. finmarchicus (van Deurs et al. 2009). Therefore, it may become increasingly difficult for several boreal seabird species to maintain adequate breeding success as this Calanus species continues its retreat. ...
Article
Full-text available
After flourishing during the second half of the twentieth century, many North Sea seabird populations are now in decline. Much evidence is accumulating that climate change is driving these negative trends in growth rate. Climate-driven changes in the physical environment may affect seabirds both directly and indirectly. Direct impacts such as increasingly common extreme weather events will result in negative physiological responses. However, climate effects on seabirds are more likely to be indirect and mediated by prey quality and availability. Mounting evidence suggests that climate impacts on lower trophic levels are altering the pathway of energy to seabirds. While the basis for changes in primary production are complex and uncertain, climate-driven changes in the availability of sandeels (primarily Ammodytes marinus) and the copepod Ca/anus finmarchicus, key prey species in adjacent trophic levels, appear to be causing a reduction in breeding success and growth rate in several British seabird species.
... 2010. Croxall et al. 2012 report that seabirds as a group are declining faster than any other group of birds and are under threat from humaninduced changes in their environment due mainly to the negative impacts of commercial fisheries and pollution. Several recent studies have also shown that seabirds are affected by climate ( Springer et al. 2007, Frederiksen et. al 2013). In the North Atlantic in particular, Frederiksen et al. (2013) report a strong positive correlation between the presence of suitable habitat for a low trophic-level copepod (Calanus finmarchicus) and long-term breeding success of several seabird species feeding at a higher trophic level. This suggests a bottom-up effect on seabirds of ...
... al 2013). In the North Atlantic in particular, Frederiksen et al. (2013) report a strong positive correlation between the presence of suitable habitat for a low trophic-level copepod (Calanus finmarchicus) and long-term breeding success of several seabird species feeding at a higher trophic level. This suggests a bottom-up effect on seabirds of a changing marine climate. ...
... The GOM has undergone at least 3 climate-driven regime shifts since the 1980s from a combination of local atmospheric warming and remote forcing from the rapidly warming Arctic Ocean (Greene et al. 2013). Concurrent northward movement of the Gulf Stream has caused widespread warming in the northeast Atlantic, with dramatic effects on seabirds there including reduced breeding success (Foster & Marrs 2012, Frederiksen et al. 2013, Miles et al. 2015. The changes in alcid diet we document here are best discussed in this context and suggest similar changes may be beginning in the northwest Atlantic. ...
... Many right whales formerly spent summers feeding on these copepods in the Bay of Fundy, but since 2011 have largely abandoned it and moved north (Pace et al. 2017). Linkages between declines of C. finmarchicus and seabirds have also been identified in the northeast Atlantic (Frederiksen et al. 2013). ...
... The impact of teleconnections has even been shown to extend to the biosphere, as teleconnection patterns strongly influence both marine and terrestrial ecosystems (e.g. Bradley and Ormerod 2001;Ottersen et al. 2001;Sims et al. 2001;Stenseth et al. 2002;Drinkwater et al. 2003;Wang and Schimel 2003;Ahas and Aasa 2006;Barbraud and Weimerskirch 2006;Forcada and Trathan 2009;Alheit et al. 2012;Frederiksen et al. 2013). The NAO/NAM have been shown to be related to the timing of bird migration in northern Europe (Huppo 2003;Sandvik et al. 2005;Stervander et al. 2005;Schummer et al. 2014), bird population dynamics in the United States (Nott et al. 2002), North Atlantic fish populations (Fromentin et al. 1998), plankton blooms (Weyhenmeyer et al. 1999), North Atlantic copepod crustaceans populations (Beaugrand et al. 2002), the timing of the growing season for many plant species (DeBeurs and Henebry 2008), and high arctic mammal populations (Forchhammer et al. 2002). ...
Chapter
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Teleconnections are spatial patterns in the atmosphere that link weather and climate anomalies over large distances across the globe. This chapter examines the spatial and temporal characteristics of teleconnections in both hemispheres, including the history of their discovery and research, and the methods by which teleconnections have been identified. We also present a detailed discussion on the leading theories of the physical mechanisms that account for the location, time scale, excitation, maintenance, and decay of teleconnections, as well as the role of tropical convection, and the inter-annual variability of teleconnections.
... Global warming, commercial fisheries, offshore activities and pollution are currently causing major changes to marine ecosystems (Beaugrand et al. 2002;Halpern et al. 2008). Among species of particular concern are seabirds, as most seabirds are top predators, and thus sensitive to changes in the marine environment that alter the availability of prey (Descamps et al. 2013;Frederiksen et al. 2013;MacDonald et al. 2015). The world's seabird populations are more threatened than other comparable bird groups (Croxall et al. 2012) and an estimated 70% of all monitored populations worldwide are declining (Paleczny et al. 2015). ...
Article
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Like many seabirds, auks spend most of the year in offshore areas. Information on which oceanic areas they rely on throughout the winter is therefore important in understanding their population dynamics and establishing appropriate conservation measures. The breeding populations of Thick-billed Murres (Uria lomvia), Common Murres (Uria aalge) and Razorbills (Alca torda) in Iceland have been reported declining for the last 30 years. Thick-billed Murres have shown the most alarming rate of decrease, while Razorbills have declined the least. To help understand these changes, we collected information about the non-breeding distribution of these three species by using light-based geolocation. Geolocators were deployed on breeding adults in three different colonies in Iceland in 2013 and 2014. Data showed that the three species’ wintering areas differed substantially. Thick-billed Murres wintered off the west coast of Greenland and East Greenland/Northern Iceland, Common Murres favoured areas around Iceland/East Greenland and to the southwest along the Mid-Atlantic Ridge, and Razorbills were mostly distributed around Iceland. Although some intraspecific variation was evident, we conclude that the population development of Thick-billed Murres in Iceland is likely to be largely influenced by environmental conditions in west Greenland, while Common Murres and Razorbills are more dependent on the oceanic area around Iceland. The results may therefore prove to be an important platform for understanding the population dynamics of these three species in Iceland and informing conservation actions.
... Sea surface temperatures in the northern North Sea are likely to increase by 1.5 to 2.5°C by 2070-2098 compared to 1961-1990 temperatures, while in the southern North Sea and Irish Sea the predicted increase is likely to be between 2.5 and 4°C (Lowe et al., 2009). As a consequence, by the mid-to late-21 st Century the waters around the UK and Ireland are modelled as being largely unsuitable for C. finmarchicus (Reygondeau and Beaugrand, 2010;Frederiksen et al., 2013). As C. finmarchicus is the preferred prey of sandeels and herring (Parrish andSaville, 1965, cited by Maravelias et al., 2000;Dalpadado et al., 1996;van Deurs et al., 2013), a large decline in abundance and frequency of this copepod will likely have a strong negative impact on these fish and the breeding seabirds that they support Raab et al., 2012;van Deurs et al., 2013). ...
Technical Report
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A technical report by the RSPB on the diet of tern chicks around the UK and Ireland. This report reviews variation in tern diet across the study region, identifying three key prey species. It then reviews the ecology and distribution of these fish species, and considers current and potential future changes to their populations in response to climate-driven changes in the marine environment.
... have declined particularly in the Atlantic Arctic (and to some extent Davis Strait-Baffin Bay), and the two latter species are subjects of detailed investigations. These declines are consistent with wider changes in the pelagic ecosystem in the North Atlantic, affecting seabirds over a wide range (Frederiksen 2010, Frederiksen et al. 2013. A similar geographical pattern is apparent for the omnivorous glaucous gull (Larus hyperboreus) and the benthic feeder common eider (Somateria mollissima), whereas the ivory gull (Pagophila eburnea) has declined throughout its Arctic range. ...
... Forage fish abundance has been linked to phytoplankton production [60] and zooplankton community composition through changes in the distribution of copepods both indicating changes in physical oceanographic conditions and influencing recruitment [61]. There can also be direct trophic links between zooplankton and seabirds, especially in the non-breeding season [62,63]. ...
Article
The Marine Strategy Framework Directive (MSFD) uses an indicator-based approach for ecosystem assessment; indicators of the state of ecosystem components ('state indicators') are used to determine whether, or not, these ecosystem components are at ‘Good Environmental Status’ relative to prevailing oceanographic conditions. Here, it is illustrated that metrics of change in plankton communities frequently provide indications of changing prevailing oceanographic conditions. Plankton indicators can therefore provide useful diagnostic information when interpreting results and determining assessment outcomes for analyses of state indicators across the food web. They can also perform a strategic role in assessing these state indicators by influencing target setting and management measures. In addition to their primary role of assessing the state of pelagic habitats against direct anthropogenic pressures, plankton community indicators can therefore also fulfil an important 'surveillance' role for other state indicators used to formally assess biodiversity status under the MSFD.
... Secondly, the differing sample periods of the datasets may play a role if distributions have changed over time. For example if breeding birds range more widely during times of food stress and, as indicated in [48], there has been increasing food stress in recent years, then the more recently sampled transect and tracking at-sea distributions may show dispersion patterns more closely resembling each other than either resemble those derived from less recent transect sampling. Thirdly, choice of modelling technique has been shown to influence the estimated spatial distribution and therefore which areas are identified as important [49]. ...
Article
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Understanding how seabirds use the marine environment is key for marine spatial planning, and maps of their marine distributions derived from transect-based surveys and from tracking of individual bird’s movements are increasingly available for the same geographic areas. Although the value of integrating these different datasets is well recognised, few studies have undertaken quantitative comparisons of the resulting distributions. Here we take advantage of four existing distribution maps and conduct a quantitative comparison for four seabird species (black-legged kittiwake Rissa tridactyla; European shag Phalacrocorax aristotelis; common guillemot Uria aalge; and razorbill Alca torda). We quantify the amount of overlap and agreement in the location of high use areas identified from either tracking or transect samples and use Bhattacharyya’s Affinity to quantify levels of similarity in the general distribution patterns. Despite multiple differences in the properties of the datasets, there was a far greater degree of overlap than would be expected by chance, except when adopting the most constrained definition of high use. Distance to the nearest conspecific colony appeared to be an important driver of the degree of similarity. Agreed areas of highest use tended to occur close to colonies and, with increasing distance from colonies, similarity between datasets declined and/or there was similarity in respect of their being relatively low usage. Interpreting reasons for agreement between data sources in some areas and not others was limited by an inability to control for the multiple potential sources of differences from both the sampling and modelling processes of the underlying datasets. Nevertheless, our quantitative comparative approach provides a valuable tool to quantify the degree to which an area’s importance is corroborated across multiple datasets, and therefore confidence that an important area has been correctly identified. This can help prioritise where the implementation of conservation measures should be targeted and identify where greatest scrutiny is required of the potential adverse environmental effects of any planned anthropogenic activities.
... These regime shifts have been generally inferred from changes in plankton assemblages (Beaugrand et al., 2015). Large-scale changes in plankton communities could explain the changes in the kittiwake population dynamics through changes in the availability of specific plankton species (such as the copepod Calanus finmarchicus in the Atlantic, Planque & Batten, 2000) that are important prey for small pelagic fish favored by seabirds like kittiwakes (Frederiksen et al., 2013, Buren et al., 2014. ...
... A range of factors drive seabird population dynamics (Ratcliffe 2004), including food availability (Furness & Birkhead 1984, Cury et al. 2011, fisheries (Tasker et al. 2000, Bicknell et al. 2013, climate change (Sandvik et al. 2012, Frederiksen et al. 2013, Macdonald et al. 2015, presence of non-native predators (Ratcliffe et al. 2009) and competition from other seabirds (Oro & Furness 2002, Votier et al. 2004. Some species, such as the Northern Gannet Morus bassanus, have been able to exploit abundance in food that suits their breeding requirements enabling large population growth (Murray et al. 2015). ...
Article
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Capsule: Long-term population trends of gulls on the Isle of Canna, Scotland, showed a correlation to fish tonnage landed in a nearby port. Aims: To assess whether gull numbers and breeding success at Canna have been influenced by the amount of fish discarded in the area. Methods: We examined data on gull breeding numbers, breeding success and diet studied at Canna from 1969 to 2014, and data on fish landings at the nearby port of Mallaig for 1985 to 2014. We examined correlations between gull and fishery data, and performed a detrended analysis of Herring Gull Larus argentatus numbers in relation to demersal fish catch (the latter as a proxy for discard volumes). Results: Gulls fed extensively on discards. Gull breeding numbers declined at Canna, especially between 2000 and 2006, the decline being more pronounced than seen in national totals. Gull breeding numbers correlated with demersal landings, even after detrending for long-term decreases in both. Conclusions: Correlation between detrended Herring Gull breeding numbers and detrended demersal fish landings provided strong evidence for a causal link between fishery discarding and gull breeding numbers.
... Marked changes have notably been ob served during the recent warming, since the mid-1990s in the waters north of Iceland (Astthorsson & Gislason 1998, Astthorsson et al. 2007, Valdimarsson et al. 2012). Our analyses on Calanus finmarchicus (see Supplement 9) suggest that intermediate pathways by which the SPG may affect guillemots may not take place through this copepod (see Supplement 10), which is considered to be a keystone species in the North Atlantic (Fort et al. 2012, Frederiksen et al. 2013. Other copepods (e.g. C. glacialis, C. hyperboreus) may be more indicative of biological shifts that may propagate until seabird level. ...
Article
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The Arctic is experiencing environmental changes at unprecedented rates. These changes are spreading throughout the entire food web, affecting apex predators such as seabirds. Brünnich's guillemot Uria lomvia populations in Svalbard archipelago have significantly declined since the mid-1990s. For longlived species such as seabirds, population growth rate is highly sensitive to changes in adult survival rates, and slight changes in survival may have large consequences at the population level. Adult survival rates, were estimated for Brünnich's guillemots individually marked and monitored from 1986 to 2011 at Bjørnøya, Svalbard. While survival appeared to be repeatedly high (mean ± SE; 95 ± 1%) from 1986 to 1995-98 (transitional years, when Svalbard guillemot colonies started to de cline), it dropped by 9-12% over the period 1995-98 to 2011. This decline coincided with the occurrence of an abrupt ecosystem shift in the North Atlantic Ocean in the mid-1990s and the weakening of the Atlantic subpolar gyre. Variations in the subpolar gyre index (SGI) were significantly associated with inter-annual variation in guillemot annual survival, and a strong gyre (i.e. cold waters on guillemot wintering grounds) was associated with high adult survival. Our results, combined with other studies, suggest that the SGI may be an important global proxy to assess oceanographic conditions and changes in marine ecosystems in the North Atlantic. © The authors 2017. Open Access under Creative Commons by Attribution Licence.
... The NPPEN model is described 132 in full details in Beaugrand et al. (2011) as well as in subsequent articles presenting different 133 study cases (e.g. Lenoir et al., 2011; Chaalali et al., 2013a; Frederiksen et al., 2013; Raybaud 134 et al., 2013; Goberville et al., 2015; Raybaud et al., 2015). The NPPEN model only requires 135 presence data and uses the Mahalanobis distance, which allows the consideration of the 136 correlations between explanatory variables (Farber and Kadmon, 2003 ). ...
Article
As species biology and ecology is profoundly influenced by climate, any climatic alteration may have severe consequences on marine pelagic ecosystems and their food webs. It remains challenging to estimate the influence of climate on both structural and functional properties of food webs. In this study, we proposed an innovative approach to assess the propagating effects of climate change on ecosystem food web. The approach is based on a sensitivity analysis of a food-web model, a linear inverse model using a Monte Carlo method coupled with a Markov Chain, in which changes in the values of parameters are driven by external Ecological Niche Model outputs. Our sensitivity analysis was restricted to parameters regarding a keystone functional group in marine ecosystems, i.e. small pelagic fish. At the ecosystem level, the consequences were evaluated using both structural and functional ecological network indices. The approach is innovative as it is the first time that these three methods were combined to assess ecological network indices sensitivity to future climatic pressure. This coupling method was applied on the French continental shelf of the Bay of Biscay for which a food-web model already exists and where future changes in the distribution of small pelagic fish have already been examined through model building and projections. In response to the sensitivity analysis corresponding to an increase in small pelagics production only, our results suggested a more active system with an intense plankton-small pelagics-seabirds chain and an efficient recycling to maximize detritus use in the system in relation with detritus export. All results combined together seemed to be in favor of a system adapting to sustain the tested increase in production of small pelagic planktivores. Finally, regarding the innovative combination of numerical tools presented, even if further investigations are still necessary to get a more realistic view of cumulative effects resulting from one given pressure (or more) on a food web (e.g. altering different biological compartments at the same time), the Ecological Network Analysis indices values showed a higher variability under the scenarios of change. Our study thus pointed out a promising methodology to assess propagating changes in structural and functional ecosystem properties.
... We demonstrated that total carbon biomass seasonally decreased 50% from the mixed to stratified periods during non-El Niño, and 72% from the mixed to stratified period during El Niño/post El Niño (Fig. 4B, Table 2). We hypothesize that such a pronounced decrease in carbon biomass (food availability) negatively impacts reproductive success, recruitment, and early survival rates of fishes, which are the target species of coastal artisanal fisheries (mainly regional-breeding species) and other non-commercial predators as was documented for the North Atlantic (Beaugrand et al., 2003;Frederiksen et al., 2013) and North Pacific Oceans (Fiedler et al., 1998). Lucano-Ramírez et al. (2016) reported that maximum reproductive activity of the striped jack Carangoides vinctus corresponds to the period of highest biological productivity (March to May) in our study area López-Sandoval et al., 2009a, 2009b. ...
Article
The seasonal succession of species community structure, abundance and carbon biomass of five zooplankton taxa (Copepoda, Euphausiacea, Chaetognatha, Amphipoda and fish larvae) and their variability during different oceanographic conditions was investigated on the continental shelf of the central Mexican Pacific (19°N, 105°W) during a monthly time-series (1996–1998). These zooplanktonic taxa included 291 species, with maximum species richness during El Niño 1997–98, when 54 tropical oceanic species invaded the continental shelf. This typical offshore community was advected onshore by the anomalous intrusion of Subsurface Equatorial water mass which caused + 7 °C temperature anomalies. Nineteen species comprised the bulk of the abundance (91%) and biomass (87%) of the five zooplankton taxa. Multivariate statistical analysis revealed four species assemblages associated with distinct oceanographic conditions: (1) mixed water column period (upwelling; February–June, non-El Niño period) characterized by high abundance and carbon biomass of omnivorous zooplankters (copepods Subeucalanus subcrassus, Centropages furcatus, Canthocalanus pauper, Temora discaudata, and Subeucalanus subtenuis, euphausiid Euphausia distinguenda, and fish larvae Bregmaceros bathymaster); (2) stratified water column period (July–January, non-El Niño period) with low-moderate abundance and biomass of the predominant species of the first group plus the euphausiid E. lamelligera, the chaetognaths Flaccisagitta enflata and Zonosagitta bedoti, and the tropical amphipod Hyperioides sibaginis; and (3 and 4) two highly diverse assemblages associated with El Niño-stratified conditions and post El Niño (July 1997–December 1998). These last two assemblages were distinguished by a high numerical dominance of carnivores (F. enflata, Z. bedoti, and H. sibaginis) and a pronounced decline of abundances of omnivore copepods, euphausiids, and fish larvae. Both the seasonal upwelling dynamics and the interannual-scale El Niño events shaped the tropical zooplankton community structure succession of this neritic ecosystem. The local community structure modulates the function and productivity of this ecosystem, which sustains regional fisheries and ecotouristic activities. More frequent, intense or even longer El Niño events may significantly decrease zooplanktonic carbon biomass and trophic transfer through the neritic epipelagic food web, resulting in impoverishment of the shelf biota with negative economic implications.
... With improved understanding of physical drivers of productivity, longer-term climate change impacts can be considered. Longer-term impacts have been implied from observed changes, but few studies have made explicit projections (but see Frederiksen et al. 2013, Sandvik et al. 2014. A clearer understanding of future impacts is essential when considering possible conservation strategies in a changing climate, especially in light of legislative frameworks that consider seabird productivity under prevailing climatic conditions (HM Government 2012). ...
Conference Paper
The black-legged kittiwake (Rissa tridactyla) is one of the UK's most abundant seabirds but the population has declined by 60% since the 1980s. Declines have been linked to rising sea surface temperatures (SSTs) that are believed to affect recruitment and growth of the lesser sandeel (Ammodytes marinus), a key kittiwake prey species, in turn causing reduced breeding success. However, these relationships have often been derived from a small number of intensively-studied colonies from a geographically limited area, and analyses have primarily considered SST within arbitrarily-defined areas surrounding breeding colonies. Consequently, important national-scale drivers may not have been detected and oceanographic indices may not accurately reflect the conditions experienced. We have attempted to address these issues by using tracking data to estimate colony-specific foraging areas for eleven colonies. Estimates of SST, stratification strength, and stratification onset date from these areas were linked to colony productivity. Higher productivity was associated with lower SSTs and weaker early-year stratification. Climate change projections indicated that rising SSTs could drive substantial kittiwake productivity declines by the late 21st Century. Finally, food web components linking physical conditions to kittiwake productivity were explored using Continuous Plankton Recorder data. Higher productivity was associated with higher sandeel abundance, which in turn was associated with higher calanoid copepod abundance. Higher Calanus finmarchicus abundance was associated with later stratification and weaker early-year stratification, whilst higher Calanus helgolandicus abundance was associated with stronger stratification throughout the year. Hence, our analyses show how changing oceanographic conditions can influence kittiwake food webs, in turn influencing breeding success; further examination of such links should improve understanding of the threats posed by climate change.
... Seabirds are also ecological sentinels of marine ecosystems across their life cycles (Durant et al., 2009;Lescroël et al., 2016), and the subject of long-term monitoring studies throughout the world (Paleczny, Hammill, Karpouzi, & Pauly, 2015). Yet, because of technological limitations and practical difficulties, most of these studies dealing with climate change impacts on seabirds focus on population processes (Descamps et al., 2017) or on their responses during the breeding season (Frederiksen, Anker-Nilssen, Beaugrand, & Wanless, 2013), rather than climate change impacts on their at-sea distributions during the non-breeding period. This is critical since conditions encountered during the non-breeding period strongly shape seabird population dynamics (Alves et al., 2013). ...
Article
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We explored the implications of reaching the Paris Agreement Objective of limiting global warming to <2°C for the future winter distribution of the North Atlantic seabird community. We predicted and quantified current and future winter habitats of five North Atlantic Ocean seabird species (Alle alle, Fratercula arctica, Uria aalge, Uria lomvia and Rissa tridactyla) using tracking data for ~1500 individuals through resource selection functions based on mechanistic modeling of seabird energy requirements, and a dynamic bioclimate envelope model of seabird prey. Future winter distributions were predicted to shift with climate change, especially when global warming exceed 2°C under a “no mitigation” scenario, modifying seabird wintering hotspots in the North Atlantic Ocean. Our findings suggest that meeting Paris agreement objectives, will limit changes in seabird selected habitat location and size in the North Atlantic Ocean during the 21st century. We thereby provide key information for the design of adaptive marine protected areas in a changing ocean.
... Anderson et al. (2014),Frederiksen et al. (2004Frederiksen et al. ( , 2013,Burthe et al. (2014),Macdonald et al. (2015) ...
Chapter
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Seabirds throughout the world are vulnerable to increasing sea temperatures, and associated climate change such as rainfall and storminess, partly through direct effects on bird physiology, but mostly through indirect bottom-up effects, with adverse effects far more frequent than new opportunities. • Some populations have already declined considerably due to climate change (emperor penguins declined by 50% due to reduction in adult survival related to reduced sea ice extent, rockhopper penguins at Campbell Island declined by 96% as sea temperature increased, a 70% reduction in ivory gull numbers has been attributed to increasing temperatures reducing Arctic sea ice, Arctic skua breeding numbers in Scotland declined by 74% during 1986-2011, black-legged kittiwake breeding numbers by 66% in the same period, both declines being thought due to increasing temperatures (predominantly affecting sandeel productivity). • Modelling predicts extinction of black-legged kittiwakes in Norway within the next 10-100 years because their breeding success and survival are both reduced by increasing sea temperature. • Some populations may redistribute polewards, but scope for redistribution is limited. • Climate envelope models predict the near-future loss as breeding species in the British Isles of Arctic tern, Arctic skua, great skua and Leach's storm-petrel, all of which are at the southern edge of breeding range in the British Isles.
... On the contrary, apart from environmental conditions and food availability, the life history of copepods in the Norwegian Sea is also shaped by topdown control by planktovorous fish, like herring (Clupea harengus) and capelin (Mallotus villosus) (Kaartvedt, 2000). Moreover, seabird breeding success is linked to C. finmarchicus abundance (Frederiksen et al., 2013), but also to environmental conditions: e.g. Moe et al. (2009) found increasing sea temperatures result in earlier breeding of black-legged kittiwake. ...
Thesis
Seasonal changes in environmental conditions in Arctic and subarctic waters, such as light or temperature, impact the timing of life cycle events of species. Interannual variation in plankton development can lead to a mismatch with higher trophic levels and have consequences for the entire food web. In this study, the spatial and temporal variability in phytoplankton growth in the northeast Atlantic is analysed over a latitudinal gradient between 62 and 82°N and a study period from 1998-2016. The phenological concept, published in previous literature on plankton bloom development, which predicted a later bloom onset and maximum, smaller maximum and decreased bloom duration with increasing latitude, is evaluated with ocean color data. Furthermore, environmental conditions, which are available on large spatial scales, namely the North Atlantic Oscillation (NAO) index and sea surface temperature (SST) are included as potential explanatory variables. Copepod datasets from deployments of the continuous plankton recorder (CPR) on the Iceland-Norway route and mainland Norway to the Svalbard archipelago are examined to explore the link between the trophic level in plankton. Apart from the decrease of the bloom duration and a weak trend towards a later onset, the maximum timing and magnitude do not show a pattern across latitudes. However, the variability of the characteristic bloom features, for example the peak timing, increases with latitude, resulting in high standard deviation of the average development. Similarly, the maximum of copepod abundance numbers in surface waters is not related to location and only a slight trend of an earlier peak at low latitudes is observed for the species Calanus finmarchicus. The maximum abundance of copepodite stages as well as of small-sized zooplankton and C. finmarchicus follow the phytoplankton bloom on large scales, but with increasing latitudes, C. finmarchicus abundances start to lag behind. The within seasonal and interannual coverage of the methods is biased by cloud cover and night (ocean colour) and length of observation period and sampling techniques (CPR). However, both ocean colour and CPR data have proven beneficial to provide important indicators in changes in phenology and insights into climate change impact on higher latitudes.
... There are likely to be multiple causes for the observed Puffin declines which could include climate change, changing fisheries practices and pollution (Mitchell et al. 2004, Carroll et al. 2017, as well as reduced recruitment of immatures into breeding colonies (Miles et al. 2015). The impact of climate change on food availability, especially Lesser Sandeels Ammodytes marinus, one of the main Puffin food sources (Miles et al. 2015), is particularly likely to affect Puffins, and other seabirds, in the Northern Isles (Frederiksen et al. 2013). A specific local threat on Orkney may be the predation by non-native Stoats Mustela erminea which have appeared on Orkney. ...
Article
Full-text available
Atlantic Puffins Fratercula arctica were counted at all known colonies in Orkney (excluding Sule Skerry) during the 2016 breeding season. Counts of individuals (IND) were made during pre-laying and incubation at all 20 sites and at six sites where burrows where physically accessible. In 2016 the Atlantic Puffin population of Orkney was estimated to be 6,675 breeding pairs (based on the counts of apparently occupied burrows [AOB] where available, and assuming that one individual represented one breeding pair for the other sites). AOB counts were higher than the IND counts at all six colonies where both methods were used. Previous Orkney Atlantic Puffin population estimates of breeding pairs were mostly based on counts of individuals on land (INDL) made during late incubation and chick rearing. While caution must be used when comparing INDL counts between years the results suggest a decline in line with studies of other Northern Isles colonies.
... Historically, spring hunting near colonies has had a strong negative impact on West Greenland colonies south of Upernavik (Kampp et al. 1994), whereas hunting pressure in the NOW area has been much lower. In recent decades, the harvest of thick-billed murres in the North Atlantic has dropped significantly due to a combination of management regulations and occupational changes (Merkel & Barry 2008;Merkel et al. 2018), and evidence is accumulating that the continued decline of many murre populations is linked to large-scale climatic and ecosystem changes in the wintering areas of the birds (Irons et al. 2008;Descamps et al. 2013;Frederiksen et al. 2013;Fluhr et al. 2017). The thick-billed murres from the NOW area primarily winter off Newfoundland, where conditions seems to be relatively favourable compared to the Southwest Greenland Open Water Area and the Central/Western North Atlantic, where many of the declining murre populations spend the winter . ...
Conference Paper
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Understanding the complex dynamics of environmental change in northern latitudes is particularly critical for arctic avian communities, which are integral components that maintain biological connections between the mid-and northern latitudes. We report on studies done in 2010-2015 in Northwest Greenland as part of a larger effort focused on understanding the population dynamics of High Arctic marine bird communities. We use several data sources and analysis techniques, including diet data, stable isotopes, and Bayesian inference, to identify the potential relationships between ecological response of coastal marine birds and rapid environmental change such as increased freshwater runoff from glacier melt, inshore oceanographic change, and cascading trophic perturbations. Our preliminary results indicate that community wide spatial and temporal dynamics of this high Arctic marine bird community are far greater during our study period than was evident in past decades. We also find that the magnitude of change is greater here in the high Arctic (eg., 78 °N) compared to low Arctic coastal marine ecosystems (eg., western Aleutian Islands, 53 °N). In particular, we show that the ecological patterns observed within such widespread arctic species as Dovekie (Alle alle), Thick-billed Murres (Uria lomvia), and Black-legged Kittiwakes (Rissa tridactyla) indicate diets are strongly perturbed from a decade earlier. Moreover, we find that the variance in environmental and ecological parameters is increasing over relatively small temporal and spatial scales. We hypothesize that these fine-scale changes are related to oceanographic and trophic-level responses to increased freshwater injection into coastal waters, in addition to larger scale perturbations possibly related to a cascade of climate-related factors.
... However, the marginal ice zone can provide a rich foraging opportunity (Hunt et al., 1996), as zooplankton and fish species often aggregate at ice edge habitats (Daase et al., 2021). Changes in sea ice extent and water temperature have resulted in changes in the available prey field for seabirds throughout the Arctic (Mallory et al., 2010;Frederiksen et al., 2013;Gall et al., 2017;Mueter et al., 2021a). For instance, in the North Atlantic, little auk wintering distribution expands and contracts with the distribution of their subarctic copepod prey, which is shifting northward (Amélineau et al., 2018). ...
Article
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Studies of the impacts of climate change on Arctic marine ecosystems have largely centered on endemic species and ecosystems, and the people who rely on them. Fewer studies have focused on the northward expansion of upper trophic level (UTL) subarctic species. We provide an overview of changes in the temporal and spatial distributions of subarctic fish, birds, and cetaceans, with a focus on the Pacific Arctic Region. Increasing water temperatures throughout the Arctic have increased "thermal habitat" for subarctic fish species, resulting in northward shifts of species including walleye pollock and pink salmon. Ecosystem changes are altering the community composition and species richness of seabirds in the Arctic, as water temperatures change the available prey field, which dictates the presence of planktivorous versus piscivorous seabird species. Finally, subarctic whales, among them killer and humpback whales, are arriving earlier, staying later, and moving consistently farther north, as evidenced by aerial survey and acoustic detections. Increasing ice-free habitat and changes in water mass distributions in the Arctic are altering the underlying prey structure, drawing UTL species northward by increasing their spatial and temporal habitat. A large-scale shuffling of subarctic and Arctic communities is reorganizing high-latitude marine ecosystems. Two transient killer whales in the Chukchi Sea in September 2017. Image credit: K.M. Stafford
... piscivorous seabird species have declined in the eastern North Atlantic has accumulated (Frederiksen 2010;Ganter & Gaston 2013;Kuletz et al. 2017). The declines appear to be linked to wide-ranging climate and ecosystem changes in the North Atlantic (Irons et al. 2008;Descamps et al. 2013;Frederiksen et al. 2013;Descamps et al. 2017). However, among planktonic and benthic feeders, some species are seemingly doing well and local changes are sometimes opposite to the general trend (Frederiksen 2017). ...
Article
The South-west Greenland Open Water Area is an internationally important wintering area for seabirds in the North Atlantic. Nearly two decades after the area was last surveyed, we conducted a replicate aerial survey in March 2017 to update information on the distribution and abundance of seabirds. With a total effort of about 5800 km, we covered the coastal area from Aasiaat (69°N) to Kap Farvel (60°N), 56% of the open water area in the fjords, and the offshore bank, Store Hellefiskebanke. Line transect survey methodology was used except in the fjords, which were censused by total counts. By means of distance sampling analyses, the abundances of the dominant species were estimated to be roughly 1100 000 king eiders (Somateria spectabilis), 443 000 common eiders (Somateria mollissima), 42 000 long-tailed ducks (Clangula hyemalis) and 76 000 Iceland gulls/glaucous gulls (Larus glaucoides/Larus hyperboreus). For the great black-backed gull (Larus marinus), great cormorant (Phalacrocorax carbo), mallard (Anas platyrhynchos) and red-breasted merganser (Mergus serrator), we present the first winter population estimates for the area (6100, 7700, 7600 and 3200 individuals, respectively). Areas around Kangaatsiaq, Nuuk and Julianehåbsbugten were identified as key wintering sites, as was Store Hellefiskebanke which held 99% of the king eiders. For all species assessed in 1999, abundance in the coastal survey area was considerably lower in 2017. In some cases, this may be due to changes in distribution patterns. However, for thick-billed murre (Uria lomvia), long-tailed duck and black-legged kittiwake (Rissa tridactyla), the reduced coastal abundances coincide with declining breeding populations.
... herring) for food, they have the potential to overgraze on the zooplankton community [73]. This could lead to a decline in zooplankton abundance, especially of C. finmarchicus, which in turn can have detrimental effects on the food-web structure, as well as the survival of many marine fish, bird and whale species [29,30,[82][83][84]. Studies have shown, that mackerel on several occasions seem to prefer fish larvae to zooplankton [24,27], and reports say that mackerel readily feed on juvenile herring, capelin, sand eel among others [27,57,73,85]. ...
Article
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Predator-prey relations, as well as the trophic ecology of highly migratory marine species, is important to understand their impact on the ecosystem. Conventional methods were used to study the diet composition and feeding strategy of the Northeast Atlantic mackerel (Scombrus scomber), during their summer feeding migration to Icelandic waters in 2009–2014. In addition, generalised additive modelling (GAM) was used to determine which biological and environmental factors contribute to the variation of their stomach weight in the years 2011–2014. From the dietary analysis, we found that calanoid copepods (especially Calanus finmarchicus) were the most important contributor to the overall diet of mackerel in the years studied. Although in some years and areas, they also preyed heavily on larger prey items such as euphausiids, amphipods and megalopa larvae of crab and shrimp. The GAM showed that temperature and the time the day of sampling were significant explanatory variables for the stomach weight, while zooplankton biomass did not seem to have much influence. The Northeast Atlantic mackerel are ferocious feeders upon copepods, as well as exhibiting an overall opportunistic feeding strategy. During their feeding migration in Icelandic waters, they were found to feed on the most dominant species available to them.
... The investigation of shifts in breeding distributions of Arctic species is in its infancy, but theoretical exercises predicting shifts in winter and summer ranges are contributing a basis for forecasting potential changes. Shifts in breeding distribution have been predicted for Arctic-breeding shorebirds [173] as well as for Arctic seabirds [174] given the northward shifts of their prey [175]. In this way, climate change may result in shifts in migration destinations and even flyways, for example the predicted establishment of wintering populations of little auks (Alle alle) in the Pacific, which would facilitate trans-Arctic migrations [174]. ...
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Climate warming in the Arctic has led to warmer and earlier springs, and as a result, many food resources for migratory animals become available earlier in the season, as well as become distributed further northwards. To optimally profit from these resources, migratory animals are expected to arrive earlier in the Arctic, as well as shift their own spatial distributions northwards. Here, we review literature to assess whether Arctic migratory birds and mammals already show shifts in migration timing or distribution in response to the warming climate. Distribution shifts were most prominent in marine mammals, as expected from observed northward shifts of their resources. At least for many bird species, the ability to shift distributions is likely constrained by available habitat further north. Shifts in timing have been shown in many species of terrestrial birds and ungulates, as well as for polar bears. Within species, we found strong variation in shifts in timing and distributions between populations. Ou r review thus shows that many migratory animals display shifts in migration timing and spatial distribution in reaction to a warming Arctic. Importantly, we identify large knowledge gaps especially concerning distribution shifts and timing of autumn migration, especially for marine mammals. Our understanding of how migratory animals respond to climate change appears to be mostly limited by the lack of long-term monitoring studies.
... According to IUCN, Arctic tern is globally considered as decreasing (BirdLife International 2018), though detailed information is notoriously lacking. The main effects identified to be responsible for this decrease are predation (Nordström et al. 2002), egging (Gilchrist and Robertson 1999), and food shortage (Schreiber and Kissling 2005;Vigfúsdóttir 2012;Frederiksen et al. 2013;Vigfúsdóttir et al. 2013). According to the IUCN, the other important threatening factor is yachting and other leisure activities, which have led to a significant increase in disturbance of breeding terns (BirdLife International 2018). ...
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Nesting birds often respond to human disturbance as to a predatory act. In the case of the high Arctic, the disturbance of incubating birds may bring further complications due to egg cooling. In addition, it is assumed that birds in the high Arctic are not shy and do not respond to human presence fearfully. We tested how quickly the Arctic terns (Sterna paradisaea) nesting in two colonies in Svalbard return to the nest after human disturbance. One colony was situated inside a town where the terns were regularly harassed by human presence. The second colony was on a glacial foreland where breeding terns have limited experience with humans. We found that terns without frequent experience with humans returned to the nest about 5 min after disturbance, while urban terns habituated to human presence returned within a few tens of seconds. The urban terns in this way likely solve the risk of spending too much time off the nest, which could lead under the conditions of the high Arctic to the stopping of embryogenesis. Terns from a remote colony do not show lower hatching success of their eggs than the urban ones, however, incubation and the whole population of terns could be threatened when there is more frequent disturbance by researchers or tourists.
... These whales, which mainly feed on this copepod (Baumgartner and Mate 2003;Pendleton et al. 2012), and of which only 409 individuals remain in the world (Pettis et al. 2019), may be irretrievably affected by these changes in prey availability (Meyer-Gutbrod and Greene 2018). Birds such as the common guillemot (Uria aalge) or the Atlantic puffin (Fratercula arctica), whose diet is based on fish that feed on C. finmarchicus, will entrust their survival to their adaptability to move northwards in search of prey (Frederiksen et al. 2013). Little auk (Alle alle), which feeds directly on C. glacialis, a more nutritious species than C. finmarchicus (Kidawa et al. 2014), could also be affected if this species is replaced by C. finmarchicus in northern waters (Karnovsky et al. 2010;Amélineau et al. 2019). ...
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The nutraceutical market for EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) is promoting fishing for Euphasia superba (Antarctic krill) in the Southern Ocean and Calanus finmarchicus in Norwegian waters. This industry argues that these species are underexploited, but they are essential in their ecosystems, and climate change is altering their geographical distribution. In this perspective, we advocate the cessation of fishing for these species to produce nutraceuticals with EPA and DHA. We argue that this is possible because, contrary to what this industry promotes, the benefits of these fatty acids only seem significant to specific population groups, and not for the general population. Next, we explain that this is desirable because there is evidence that these fisheries may interact with the impact of climate change. Greener sources of EPA and DHA are already available on the market, and their reasonable use would ease pressure on the Arctic and Antarctic ecosystems.
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Climate change impacts on vertebrates have consequences for marine ecosystem structures and services. We review marine fish, mammal, turtle, and seabird responses to climate change and discuss their potential for adaptation. Direct and indirect responses are demonstrated from every ocean. Because of variation in research foci, observed responses differ among taxonomic groups (redistributions for fish, phenology for seabirds). Mechanisms of change are (i) direct physiological responses and (ii) climate-mediated predator-prey interactions. Regional-scale variation in climate-demographic functions makes range-wide population dynamics challenging to predict. The nexus of metabolism relative to ecosystem productivity and food webs appears key to predicting future effects on marine vertebrates. Integration of climate, oceanographic, ecosystem, and population models that incorporate evolutionary processes is needed to prioritize the climate-related conservation needs for these species.
Article
Understanding the determinants of species’ distributions is a fundamental aim in ecology and a prerequisite for conservation but is particularly challenging in the marine environment. Advances in bio‐logging technology have resulted in a rapid increase in studies of seabird movement and distribution in recent years. Multi‐colony studies examining the effects of intra‐ and inter‐colony competition on distribution have found that several species exhibit inter‐colony segregation of foraging areas, rather than overlapping distributions. These findings are timely given the increasing rate of human exploitation of marine resources and the need to make robust assessments of likely impacts of proposed marine developments on biodiversity. Here we review the occurrence of foraging area segregation reported by published tracking studies in relation to the density‐dependent hinterland (DDH) model, which predicts that segregation occurs in response to inter‐colony competition, itself a function of colony size, distance from the colony and prey distribution. We found that inter‐colony foraging area segregation occurred in 79% of 39 studies. The frequency of occurrence was similar across the four seabird orders for which data were available, and included species with both smaller (10–100 km) and larger (100–1000 km) foraging ranges. Many predictions of the DDH model were confirmed, with examples of segregation in response to high levels of inter‐colony competition related to colony size and proximity, and enclosed landform restricting the extent of available habitat. Moreover, as predicted by the DDH model, inter‐colony overlap tended to occur where birds aggregated in highly productive areas, often remote from all colonies. The apparent prevalence of inter‐colony foraging segregation has important implications for assessment of impacts of marine development on protected seabird colonies. If a development area is accessible from multiple colonies, it may impact those colonies much more asymmetrically than previously supposed. Current impact assessment approaches that do not consider spatial inter‐colony segregation will therefore be subject to error. We recommend the collection of tracking data from multiple colonies and modelling of inter‐colony interactions to predict colony‐specific distributions.
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The North Atlantic copepods Calanus finmarchicus and C. helgolandicus are moving north in response to rising temperatures. Understanding the drivers of their relative geographic distributions is required in order to anticipate future changes. To explore this, we created a new spatially explicit stage-structured model of their populations throughout the North Atlantic. Recent advances in understanding Calanus biology, including U-shaped relationships between growth and fecundity and temperature, and a new model of diapause duration are incorporated in the model. Equations were identical for both species, but some parameters were species-specific. The model was parameterized using Continuous Plankton Recorder Survey data and tested using time series of abundance and fecundity. The geographic distributions of both species were reproduced by assuming that only known interspecific differences and a difference in the temperature influence on mortality exist. We show that differences in diapause capability are not necessary to explain why C. helgolandicus is restricted to the continental shelf. Smaller body size and higher overwinter temperatures likely make true diapause implausible for C. helgolandicus. Known differences were incapable of explaining why only C. helgolandicus exists southwest of the British Isles. Further, the fecundity of C. helgolandicus in the English Channel is much lower than we predict. We hypothesize that food quality is a key influence on the population dynamics of these species. The modeling framework presented can potentially be extended to further Calanus species.
Article
The Arctic is currently experiencing the most rapid warming on Earth. Arctic species communities are expected to be restructured with species adapted to warmer conditions spreading poleward and, if already present, becoming more abundant. We tested this prediction using long-term monitoring data (2009-2018) from nine of the most common seabird species breeding in the High Arctic Svalbard archipelago. This region is characterized by rapidly warming ocean temperatures, declining sea-ice concentrations and an increasing influence of Atlantic waters. Concurrent with these environmental changes, we found a shift in the Svalbard seabird community, with an increase in abundance of boreal species (defined here as species breeding commonly in temperate environments) and a decline in arctic species (species breeding predominantly in the Arctic). Combined with previous observations from lower trophic levels, our results confirmed that part of the Arctic fauna is moving from an arctic to a boreal (or north temperate) state, a process referred to as a "borealization". Spatial variations exist among colonies for some species, indicating that local conditions may affect the trajectories of specific populations and potentially counter-balance the consequences of large-scale climate warming.
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Bottom-up” influences, that is, masting, plus population density and climate, commonly influence woodland rodent demography. However, “top-down” influences (predation) also intervene. Here, we assess the impacts of masting, climate, and density on rodent populations placed in the context of what is known about “top-down” influences. To explain between-year variations in bank vole Myodes glareolus and wood mouse Apodemus sylvaticus population demography, we applied a state-space model to 33 years of catch-mark-release live-trapping, winter temperature, and precise mast-collection data. Experimental mast additions aided interpretation. Rodent numbers in European ash Fraxinus excelsior woodland were estimated (May/June, November/December). December–March mean minimum daily temperature represented winter severity. Total marked adult mice/voles (and juveniles in May/June) provided density indices validated against a model-generated population estimate; this allowed estimation of the structure of a time-series model and the demographic impacts of the climatic/biological variables. During two winters of insignificant fruit-fall, 6.79 g/m2 sterilized ash seed (as fruit) was distributed over an equivalent woodland similarly live-trapped. September–March fruit-fall strongly increased bank vole spring reproductive rate and winter and summer population growth rates; colder winters weakly reduced winter population growth. September–March fruit-fall and warmer winters marginally increased wood mouse spring reproductive rate and September–December fruit-fall weakly elevated summer population growth. Density dependence significantly reduced both species' population growth. Fruit-fall impacts on demography still appeared after a year. Experimental ash fruit addition confirmed its positive influence on bank vole winter population growth with probable moderation by colder temperatures. The models show the strong impact of masting as a “bottom-up” influence on rodent demography, emphasizing independent masting and weather influences; delayed effects of masting; and the importance of density dependence and its interaction with masting. We conclude that these rodents show strong “bottom-up” and density-dependent influences on demography moderated by winter temperature. “Top-down” influences appear weak and need further investigation.
Article
Over four decades there were pronounced within‐season changes in the proportion of a key prey species (Lesser Sandeel Ammodytes marinus) in Common Guillemot Uria aalge chick diet. As Sandeels became scarcer their occurrence was largely confined to the early part of the chick period. Consequently, the mean annual proportion of Sandeels was poorly estimated if sampling occurred within a short time window, particularly if this was early or late in the season. Within‐season variation is rarely considered in diet monitoring, but our results highlight the need for further analyses across other species and sites to develop a deeper understanding of how best to optimise sampling protocols.
Article
Recent observations confirm the rising temperatures of Atlantic waters transported into the Arctic Ocean via the West Spitsbergen Current (WSC). We studied the overall abundance and population structure of the North Atlantic keystone zooplankton copepod Calanus finmarchicus, which is the main prey for pelagic fish and some seabirds, in relation to selected environmental variables in this area between 2001 and 2011, when warming in the Arctic and Subarctic was particularly pronounced. Sampling within a three-week time window each summer demonstrated that trends in the overall abundance of C. finmarchicus varied between years, with the highest values in "extreme" years, due to high numbers of nauplii and early copepodite stages in colder years (2001, 2004, 2010), and contrary to that, the fifth copepodite stage (C5) peaking in warm years (2006, 2007, 2009). The most influential environmental variable, driving C. finmarchicus life cycle was temperature, which promoted an increased C5 abundance when the temperature was above 6°C, indicating earlier spawning and/or accelerated development, and possibly leading to their development to adults later in the summer and spawning for the second time, given adequate food supply. Based on the presented high interannual and spatial variability, we hypothesize that under a warmer climate, C. finmarchicus may annually produce two generations in the southern part of the WSC, what in turn could lead to food web reorganization of important top predators, such as little auks, and induce northward migrations of fish, especially the Norwegian herring. This article is protected by copyright. All rights reserved.
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An increasing number of studies report coordinated chick provisioning by avian parents. Although the pattern of parental coordination varies across species, broad occurrence of this coordination suggests that it has an adaptive value: it may increase individual fitness via higher offspring survival, faster offspring growth rate and/or higher body reserves of the parents. However, to what extent the pattern of coordinated provisioning in a species represents a flexible response to current foraging conditions remains an open question. Here, we examined coordination of chick provisioning in the Little Auk (Alle alle), a planktivorous seabird species that breeds in the Arctic. Harsh environmental conditions impose bi-parental care on this species, and high variability within and across breeding seasons promotes flexibility in parental involvement to secure breeding success. During the chick rearing period, parents exhibit a dual-foraging strategy (i.e., alternating long foraging trips, serving to maintain the adults' body reserves, with several short trips aimed to provision the chick). We examined coordination of parental provisioning across five breeding seasons varying in terms of environmental conditions and found that the parents indeed coordinate their provisioning, avoiding performing long trips simultaneously and thus enabling a more even distribution of feeding through time. We also examined chick body condition in relation to the level of parental coordination to test the potential adaptive value of coordination, but we found no significant relationship between these two parameters. We found high variability in the level of the coordination between pairs, and this variability was similar across all study seasons, which represented a wide range of experienced environmental conditions. Nevertheless, we found that the energy density of food loads delivered to chicks was associated with the level of parental coordination: when conditions were characterized by the delivery of higher-energy food loads, the level of coordination exhibited by the studied population was higher. These findings suggest that environmental conditions somehow affect parental coordination, but the range of the environmental variation could be still below a critical threshold of extreme conditions that would trigger more pronounced modifications of parental foraging patterns and coordination.
Thesis
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The earth's climate is changing rapidly, with pronounced impacts observed in all well studied ecosystems throughout the globe. Climate-mediated impacts are particularly marked and rapid within marine ecosystems. At the apex of such systems, marine top predators, such as seabirds, are vulnerable to direct and indirect climate-mediated effects, which may alter foraging capacity and prey availability. Consequently, many seabird populations are displaying pronounced changes in diet composition and declining demographic trends, yet the mechanisms underpinning these responses remain largely untested. Although many studies have quantified seabird diet during the breeding season, the climate-related mechanisms determining long-term trends in diet composition are less well understood. Further, as the majority of seabird mortality occurs during winter, the diet of seabirds in winter is a key knowledge gap. Demographic trends have also been observed in numerous seabird species but, as with diet, we have limited understanding of the key mechanisms whereby climate is driving these trends. Finally, analyses of climate have focussed on broad scale processes, yet variation in microclimate may also be a key determinant of fine-scale distribution and demography within seabird colonies, yet this potential factor has been overlooked. As a long-lived species with highly variable demography and plastic foraging habits, the European shag Phalacrocorax aristotelis provides an ideal species to investigate the impacts of environmental change on marine top-predator demography. This thesis uses demographic and diet datasets collected from a shag population breeding on the Isle of May, southeast Scotland, over half a century. By combining these data with environmental covariates, collected over a range of temporal and spatial scales, I quantify the response of this population to pronounced environmental change within the North Sea over the last five decades. My thesis reveals that the diet of nestling shags in this population has changed dramatically over this period, from an almost complete dependence on lesser sandeel Ammodytes marinus to a range of prey types. Crucially, a suite of environmental covariates, including daily wind and long-term ocean warming, has contributed to this change in diet. The diet in winter displayed similar temporal trends (reduced sandeel and greater diversity). However, I found that the reduction in sandeel occurrence was more marked during the non-breeding period, with potential demographic consequences. I also documented a substantial increase in productivity and rapid phenological advancement over the last half a century. Crucially, the productivity trend was linked to this advancing phenology, which in turn was determined by conditions experienced in late winter and in the previous breeding season. Finally, pronounced fine-scale distributional trends occurred in this colony, with an increasing proportion of individuals breeding on the northeast side of the island, showing more rapid improvements in reproductive output than the declining sub-colonies in the southwest. This redistribution may benefit the population since exposure is a key factor in productivity and the prevailing wind direction is westerly. Overall, these results suggest that substantial dietary and demographic plasticity in shags may confer some resilience in this species to predicted future climate-mediated environmental change.
Article
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Rapid anthropogenic climate change potentially severely reduces avian breeding success. While the consequences of high temperatures and drought are reasonably well-studied within single breeding seasons, their impacts over decadal time scales are less clear. We assessed the effects of air temperature (T air) and drought on the breeding output of southern yellow-billed hornbills (Tockus leucomelas; hornbills) in the Kalahari Desert over a decade (2008-2019). We aimed to document trends in breeding performance in an arid-zone bird during a time of rapid global warming and identify potential drivers of variation in breeding performance. The breeding output of our study population collapsed during the monitoring period. Comparing the first three seasons (2008-2011) of monitoring to the last three seasons (2016-2019), the mean percentage of nest boxes that were occupied declined from 52% to 12%, nest success from 58% to 17%, and mean fledglings produced per breeding attempt from 1.1 to 0.4. Breeding output was negatively correlated with increasing days on which T max (mean maximum daily T air) exceeded the threshold T air at which male hornbills show a 50% likelihood of engaging in heat dissipation behavior [i.e., panting (T thresh; T air = 34.5 • C)] and the occurrence of drought within the breeding season, as well as later dates for entry into the nest cavity (i.e., nest initiation) and fewer days post-hatch, spent incarcerated in the nest by the female parent. The apparent effects of high T air were present even in non-drought years; of the 115 breeding attempts that were recorded, all 18 attempts that had ≥ 72% days during the attempt on which T max > T thresh failed (equivalent to T max during the attempt ≥ 35.7 • C). This suggests that global warming was likely the primary driver of the recent, rapid breeding success collapse. Based on current warming trends, the T max threshold of 35.7 • C, above which no successful breeding attempts were recorded, will be exceeded during the entire hornbill breeding season by approximately 2027 at our study site. Therefore, our findings support the prediction that climate change may drive rapid declines and cause local extinctions despite the absence of direct lethal effects of extreme heat events.
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Cheung, W. W. L., Dunne, J., Sarmiento, J. L., and Pauly, D. 2011. Integrating ecophysiology and plankton dynamics into projected maximum fisheries catch potential under climate change in the Northeast Atlantic. – ICES Journal of Marine Science, 68: 1008–1018. Previous global analyses projected shifts in species distributions and maximum fisheries catch potential across ocean basins by 2050 under the Special Report on Emission Scenarios (SRES) A1B. However, these studies did not account for the effects of changes in ocean biogeochemistry and phytoplankton community structure that affect fish and invertebrate distribution and productivity. This paper uses a dynamic bioclimatic envelope model that incorporates these factors to project distribution and maximum catch potential of 120 species of exploited demersal fish and invertebrates in the Northeast Atlantic. Using projections from the US National Oceanic and Atmospheric Administration's (NOAA) Geophysical Fluid Dynamics Laboratory Earth System Model (ESM2.1) under the SRES A1B, we project an average rate of distribution-centroid shift of 52 km decade−1 northwards and 5.1 m decade−1 deeper from 2005 to 2050. Ocean acidification and reduction in oxygen content reduce growth performance, increase the rate of range shift, and lower the estimated catch potentials (10-year average of 2050 relative to 2005) by 20–30% relative to simulations without considering these factors. Consideration of phytoplankton community structure may further reduce projected catch potentials by ∼10%. These results highlight the sensitivity of marine ecosystems to biogeochemical changes and the need to incorporate likely hypotheses of their biological and ecological effects in assessing climate change impacts.
Research
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This file contains the contents, references, general introduction and discussion. Please refer to the individual files for the chapters. For chapter 3 "How does climatic variation affect seabird population sizes?" please refer to Russell et al. 2015 in Diversity and Distributions.
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The temperature of the upper 300 m of the North Atlantic increased by about 0.57°C between 1984 and 1999. but this underlying trend was overlain with substantial geographic and interannual variability. Northward shifts occurred in the distribution of many commercial and non-commercial fish species in the NE Atlantic during the 1990s. New records were established for a number of Mediterranean and NW African species on the south coast of Portugal. Red mullet (Mullus surmuletus) and bass (Dicentrarchus labrax) extended their ranges northward to western Norway and catches of the former increased throughout the 1990s in the North Sea. Abundance or relative abundance of warm-water commercial species of gadoids and flatfish generally increased during the 1990s, but like the warming trend the changes in distribution and abundance were by no means uniform and there was considerable interannual variability. There were also examples of southward shifts for some species, which can be related to local hydrographic conditions, such as upwelling. Information on distribution and abundance of Greenland cod (Gadus morhua L.) and Norwegian spring spawning herring (Clupea harengus) during a previous warming period in the late 1920s and 1930s is also presented and compared with changes in the 1990s.
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We show that the distributions of both exploited and nonexploited North Sea fishes have responded markedly to recent increases in sea temperature, with nearly two-thirds of species shifting in mean latitude or depth or both over 25 years. For species with northerly or southerly range margins in the North Sea, half have shown boundary shifts with warming, and all but one shifted northward. Species with shifting distributions have faster life cycles and smaller body sizes than nonshifting species. Further temperature rises are likely to have profound impacts on commercial fisheries through continued shifts in distribution and alterations in community interactions.
Conference Paper
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About 3 million pairs of seabirds breed in North Norway and along the Kola Peninsula in some of the largest seabird colonies in the North Atlantic. The most numerous species are Atlantic puffins (Fratercula arctica), kittiwakes (Rissa tridactyla), and common murres (Uria aalge), and their main prey consists of capelin (Mallotus villosus), herring (Clupea harengus), and sand lance (Ammodytes spp.). The numbers of puffins, kittiwakes, and murres have changed dramatically over the last 30-40 years. While some local populations of the kittiwake west of the North Cape have increased or been fairly stable, those of the puffin and murres have decreased. For example, the puffin population at Røst, Lofoten decreased from about 1.4 million pairs in 1979 to only 500-600,000 pairs during the last few years. At Røst, the decrease in the puffin population and in part that of the common murre was due to long-term failures in chick production through starvation. For puffins this was caused by the collapse in the Norwegian herring stock in the late 1960s. East of the North Cape, the kittiwake and common murre populations have increased since about 1960, probably as a result of an increased availability of capelin. Murre numbers continue to increase today but experienced a collapse of about 80% in their numbers in 1985-1987. This collapse was the result of an extraordinarily high adult mortality during the winter which was associated with the collapse of the Barents Sea capelin stock. The capelin stock is now low and kittiwake numbers are showing signs of a decrease. Short-term responses on Røst and colonies in East Finnmark and Kola are documented by close correlations between choice of chick food and/or breeding success and indices of the abundance of the main prey fish. This paper presents details of these and other seabird-fish interactions in these waters.
Article
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Global climate change is expected to modify the spatial distribution of marine organisms. However, projections of future changes should be based on robust information on the ecological niche of species. This paper presents a macroecological study of the environmental tolerance and ecological niche (sensu Hutchinson 1957, i.e. the field of tolerance of a species to the principal factors of its environment) of Calanus finmarchicus and C. helgolandicus in the North Atlantic Ocean and adjacent seas. Biological data were collected by the Continuous Plankton Recorder (CPR) Survey, which samples plankton in the North Atlantic and adjacent seas at a standard depth of 7 m. Eleven parameters were chosen including bathymetry, temperature, salinity, nutrients, mixed-layer depth and an index of turbulence compiled from wind data and chlorophyll a concentrations (used herein as an index of available food). The environmental window and the optimum level were determined for both species and for each abiotic factor and chlorophyll concentration. The most important parameters that influenced abundance and spatial distribution were temperature and its correlates such as oxygen and nutrients. Bathymetry and other water-column-related parameters also played an important role. The ecological niche of C. finmarchicus was larger than that of C. helgolandicus and both niches were significantly separated. Our results have important implications in the context of global climate change. As temperature (and to some extent stratification) is predicted to continue to rise in the North Atlantic sector, changes in the spatial distribution of these 2 Calanus species can be expected. Application of this approach to the 1980s North Sea regime shift provides evidence that changes in sea temperature alone could have triggered the substantial and rapid changes identified in the dynamic regimes of these ecosystems. C. finmarchicus appears to be a good indicator of the Atlantic Polar Biome (mainly the Atlantic Subarctic and Arctic provinces) while C. helgolandicus is an indicator of more temperate waters (Atlantic Westerly Winds Biome) in regions characterised by more pronounced spatial changes in bathymetry.
Article
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Despite contrasting population trends ranging from –3 to +11% per annum, the annual survival rates of Atlantic puffins Fratercula arctica in the 5 colonies spanning the species range in the east Atlantic were virtually identical over a 10 to 15 yr period, giving no support to the hypothesis that variation in population growth rates is driven by adult survival. The extent to which survival varied among years differed markedly between colonies. Similarities between colonies in the patterns of inter-annual variation in survival did not reflect similarities in wintering areas, as indicated by recoveries of ringed birds, nor the geographic proximity of the colonies. However, survival in 4 of the 5 colonies correlated with sea surface temperatures around each colony 2 yr earlier. The relationship between survival and sea temperature was positively correlated with the effects of sea temperature on recruitment of the Atlantic puffin’s main prey species, the lesser sandeel Ammodytes marinus, the herring Clupea harengus and the capelin Mallotus villosus.
Article
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Dolgov, A. V., Johannesen, E., Heino, M., and Olsen, E. 2010. Trophic ecology of blue whiting in the Barents Sea. – ICES Journal of Marine Science, 67: 483–493. Blue whiting (Micromesistius poutassou) are distributed throughout the North Atlantic, including the Norwegian and Barents Seas. In recent years, both abundance and distribution of blue whiting in the Barents Sea have increased dramatically. Therefore, to evaluate the trophic impact of this increase, we analysed the diet of the species. In all, 54 prey species or taxa were identified, the main prey being krill. However, the diet varied geographically and ontogenetically: the proportion of fish in the diet was higher in large blue whiting and in the north of the range. Blue whiting overlap geographically with other pelagic species at the edge of their distribution in the Barents Sea, with juvenile herring in the south, with polar cod in the north, and with capelin in the northeast. The overlap in diet between blue whiting and these other pelagic species ranged from 6 to 86% and was greatest with capelin in areas where both species feed on hyperiids and krill. The importance of blue whiting as prey for predatory fish was highest in the areas of greatest abundance, but overall, blue whiting were seemingly unimportant as prey of piscivorous fish in the Barents Sea.
Article
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The lesser sandeel Ammodytes marinus is a key prey species for many avian predators in the North Sea, and is the target of the largest single species fishery in the area. This has led to concern about the potential impact of the fishery on seabirds. The most vulnerable predatory species are small and surface-feeding, characteristics that are exemplified by the black-legged kittiwake Rissa tridactyla. This paper reports on the first assessment of seasonal changes in prey composition and prey size for the kittiwake in the North Sea during 4 breeding seasons (1997 to 2000) in which breeding success varied dramatically. Kittiwake diet showed little inter-annual variation, with a well-defined seasonal change from planktonic crustacea in early spring, to 1+ group sandeels in April and May, to 0 group sandeels in June and July. However, there was evidence that temporal differences in sandeel life history events were well reflected in both kittiwake diet and breeding success. Thus, the most successful year (2000) was characterised by the earliest appearance of 0 group sandeels, while the least successful season had the latest appearance. There was also a link between annual variations in breeding success and sandeel size such that success was lower when 0 group sandeels were smaller and hence of lower energy value. Our study included 3 seasons (1997, 1998, 1999) during which the industrial fishery was operating within 50 km of the study colony and 1 (2000) in which the fishing grounds were closed. The higher breeding success in 2000 than in the other years suggests that the closure of the fishery might have had an immediate and positive effect on kittiwake productivity. However, as the dietary data indicated, the earlier appearance and rapid growth rates of 0 group sandeels in 2000 suggests that the enhanced breeding success was more likely to have been a response to environmental factors influencing the growth and timing of life history transitions of this prey.
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Results are presented from a new version of the Hadley Centre coupled model (HadCM3) that does not require flux adjustments to prevent large climate drifts in the simulation. The model has both an improved atmosphere and ocean component. In particular, the ocean has a 1.25° × 1.25° degree horizontal resolution and leads to a considerably improved simulation of ocean heat transports compared to earlier versions with a coarser resolution ocean component. The model does not have any spin up procedure prior to coupling and the simulation has been run for over 400 years starting from observed initial conditions. The sea surface temperature (SST) and sea ice simulation are shown to be stable and realistic. The trend in global mean SST is less than 0.009 °C per century. In part, the improved simulation is a consequence of a greater compatibility of the atmosphere and ocean model heat budgets. The atmospheric model surface heat and momentum budget are evaluated by comparing with climatological ship-based estimates. Similarly the ocean model simulation of poleward heat transports is compared with direct ship-based observations for a number of sections across the globe. Despite the limitations of the observed datasets, it is shown that the coupled model is able to reproduce many aspects of the observed heat budget.
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The use of the egg production rate of herbivorous copepods as an important parameter for understanding population dynamics and as an index of secondary production requires knowledge of the regulatory mechanisms involved and of the response to changes in food concentrations and temperature. Furthermore, the effects of season and generation on egg production have to be studied. In this context data are presented for Calanus finmarchicus from the northern North Atlantic. Prefed and prestarved females were exposed to different concentrations of the diatom Thalassiosira antarctica over 1 to 2 wk at 0 or 5 °C, and egg deposition was controlled daily. Egg production increased with higher food concentrations, but much less when prestarved. The effect of temperatures between −1.5 and 8 °C on egg production was studied in females maintained at optimum feeding conditions. Egg production rate increased exponentially over the whole temperature range by a factor of 5.2, from 14.2 to 73.4 eggs female−1 d−1, and carbon-specific egg production by 4, from 2.1 to 8.5% body C d−1. The response to starvation was also temperature dependent. In both the temperature and feeding experiments egg production rate was regulated mainly by changes of the spawning interval, while changes of clutch size were independent of experimental conditions. Different responses to optimum feeding conditions were observed in females collected in monthly intervals on three occasions between March and May. The March females deposited more clutches than the April and May females. In May, >50% of the females did not spawn at all. Maximum egg production rates were never >25% of the rate expected at 5 °C, indicating endogenous control of egg production in addition to food and temperature effects.