Bond A.L.,University of Saskatchewan |
Bond A.L.,Environment Canada |
Bond A.L.,Center for Conservation Science |
Hobson K.A.,Environment Canada |
Branfireun B.A.,University of Western Ontario
Proceedings of the Royal Society B: Biological Sciences | Year: 2015
Mercury (Hg) is increasing in marine food webs, especially at high latitudes. The bioaccumulation and biomagnification of methyl mercury (MeHg) has serious effects on wildlife, and is most evident in apex predators. The MeHg body burden in birds is the balance of ingestion and excretion, and MeHg in feathers is an effective indicator of overall MeHg burden. Ivory gulls (Pagophila eburnea), which consume ice-associated prey and scavenge marine mammal carcasses, have the highest egg Hg concentrations of any Arctic bird, and the species has declined by more than 80% since the 1980s in Canada. We used feathers from museum specimens from the Canadian Arctic and western Greenland to assess whether exposure to MeHg by ivory gulls increased from 1877 to 2007. Based on constant feather stable-isotope (d13C, d15N) values, there was no significant change in ivory gulls’ diet over this period, but feather MeHg concentrations increased 45× (from 0.09 to 4.11 mg g-1 in adults). This dramatic change in the absence of a dietary shift is clear evidence of the impact of anthropogenic Hg on this high-latitude threatened species. Bioavailable Hg is expected to increase in the Arctic, raising concern for continued population declines in high-latitude species that are far from sources of environmental contaminants. © 2015 The Author(s) Published by the Royal Society. All rights reserved.
Bond A.L.,Environment Canada |
Bond A.L.,Center for Conservation Science |
Wilhelm S.I.,Environment Canada |
Robertson G.J.,Environment Canada |
Avery-Gomm S.,Environment Canada
Waterbirds | Year: 2016
Environmental conditions in eastern Newfoundland have changed considerably since the 1970s, as both bottom-up oceanographic and anthropogenic influences on seabird populations have fluctuated considerably. The diet, reproductive success, and presumably survival of gulls are intrinsically linked to these processes, and breeding populations have declined considerably through the 1980s and 1990s. To assess the populations of breeding large gulls in the Witless Bay Ecological Reserve in eastern Newfoundland and Labrador, Canada, nests were surveyed and clutch size determined for Herring Gulls (Larus argentatus) and Great Black-backed Gulls (L. marinus) breeding on Great, Gull, and Pee Pee Islands in 2011-2012. The total number of breeding gulls of these two species combined decreased by 41% on Gull Island, 78% on Great Island and 51% on Pee Pee Island since 2000. However, the declines differed among habitat type, with modest declines on puffin slopes (-15% to -52%) and the steepest declines in meadows (-70% to -88%), suggesting that large-scale causative factors are not solely responsible for changes in population size. Clutch size did not differ from that in 2000. Differential recruitment among highly philopatric gulls stemming from bottom-up diet-related variation in breeding success may be responsible for different changes in populations among different habitats.
Gibbons D.,Center for Conservation Science |
Morrissey C.,University of Saskatchewan |
Mineau P.,Pierre Mineau Consulting
Environmental Science and Pollution Research | Year: 2014
Concerns over the role of pesticides affecting vertebrate wildlife populations have recently focussed on systemic products which exert broad-spectrum toxicity. Given that the neonicotinoids have become the fastest-growing class of insecticides globally, we review here 150 studies of their direct (toxic) and indirect (e.g. food chain) effects on vertebrate wildlife-mammals, birds, fish, amphibians and reptiles. We focus on two neonicotinoids, imidacloprid and clothianidin, and a third insecticide, fipronil, which also acts in the same systemic manner. Imidacloprid and fipronil were found to be toxic to many birds and most fish, respectively. All three insecticides exert sub-lethal effects, ranging from genotoxic and cytotoxic effects, and impaired immune function, to reduced growth and reproductive success, often at concentrations well below those associated with mortality. Use of imidacloprid and clothianidin as seed treatments on some crops poses risks to small birds, and ingestion of even a few treated seeds could cause mortality or reproductive impairment to sensitive bird species. In contrast, environmental concentrations of imidacloprid and clothianidin appear to be at levels below those which will cause mortality to freshwater vertebrates, although sub-lethal effects may occur. Some recorded environmental concentrations of fipronil, however, may be sufficiently high to harm fish. Indirect effects are rarely considered in risk assessment processes and there is a paucity of data, despite the potential to exert population-level effects. Our research revealed two field case studies of indirect effects. In one, reductions in invertebrate prey from both imidacloprid and fipronil uses led to impaired growth in a fish species, and in another, reductions in populations in two lizard species were linked to effects of fipronil on termite prey. Evidence presented here suggests that the systemic insecticides, neonicotinoids and fipronil, are capable of exerting direct and indirect effects on terrestrial and aquatic vertebrate wildlife, thus warranting further review of their environmental safety. © 2014 The Author(s).
Inger R.,University of Exeter |
Gregory R.,Center for Conservation Science |
Duffy J.P.,University of Exeter |
Stott I.,University of Exeter |
And 3 more authors.
Ecology Letters | Year: 2015
Biodiversity is undergoing unprecedented global decline. Efforts to slow this rate have focused foremost on rarer species, which are at most risk of extinction. Less interest has been paid to more common species, despite their greater importance in terms of ecosystem function and service provision. How rates of decline are partitioned between common and less abundant species remains unclear. Using a 30-year data set of 144 bird species, we examined Europe-wide trends in avian abundance and biomass. Overall, avian abundance and biomass are both declining with most of this decline being attributed to more common species, while less abundant species showed an overall increase in both abundance and biomass. If overall avian declines are mainly due to reductions in a small number of common species, conservation efforts targeted at rarer species must be better matched with efforts to increase overall bird numbers, if ecological impacts of birds are to be maintained. © 2014 John Wiley & Sons Ltd/CNRS.
Bond A.L.,University of Saskatchewan |
Bond A.L.,Center for Conservation Science
Waterbirds | Year: 2016
The diets of gulls (Laridae) can have consequences for reproductive success, chick growth, and survival, yet there have been no quantitative assessments in eastern Newfoundland since the early 1970s. The diet of Herring Gulls (Larus argentatus) was examined through regurgitated prey items and pellets on Gull Island, Witless Bay, Newfoundland and Labrador, Canada, in 2012, and compared with similar data from 1970-1971. There was a significant shift in Herring Gull diet composition from blue mussels (Mytilus edulis) and capelin (Mallotus villosus) in the 1970s to garbage and Common Murre (Uria aalge) eggs in 2012. Delays in capelin spawning and the large increase in breeding Common Murres on Gull Island are likely factors influencing Herring Gull diet. Garbage, which includes human food scraps as well as plastic debris, now constitutes the single largest diet item for Herring Gulls, corresponding with a global increase in plastic pollution. The consistently low contribution of fisheries discards suggests that changes in fishing practices and availability of discards are only one possible factor in the Herring Gull decline in Witless Bay.
Hiley J.R.,University of York |
Bradbury R.B.,Center for Conservation Science |
Thomas C.D.,University of York
Diversity and Distributions | Year: 2014
Aim: Protected wildlife habitats provide valuable stepping stones for species that shift their distributions in response to climatic and other environmental changes, but they might also aid the spread of invasive alien species. Here, we quantify the use of protected areas (PAs) by both introduced and natural wetland colonists in the UK to analyse patterns of colonization and examine the propensity of invaders to use PAs. Location: United Kingdom. Methods: We calculate PA associations for six species of wetland birds deliberately introduced to the UK and compare these with eight others that have recently colonized the UK naturally. We assess PA associations at three different stages of establishment - first breeding in each county, early establishment of a population (4-6 years after initial breeding) and subsequent consolidation (14-16 after initial breeding) - and analyse changes in PA association over time. Results: Introduced wetland bird species were less associated with PAs than natural colonists at each stage of establishment. During the later stages of colonization, the PA association of introduced species tended to increase. In contrast, natural colonists usually colonized PAs first, and their established populations subsequently spread into non-PA sites. Main conclusions: The United Kingdom PA network did not facilitate the invasion of introduced species during the initial stages of their colonization, but was vulnerable to colonization as populations established. This is in contrast to natural colonists, which are more reliant on PAs during initial colonization but become less dependent as they establish. During a period of rapid environmental change, PAs have facilitated expansions of natural colonists, without acting as the prime sites for invasion by introduced species. © 2014 John Wiley & Sons Ltd.
Dunn J.C.,Center for Conservation Science |
Morris A.J.,Center for Conservation Science
Bird Study | Year: 2012
Capsule Turtle Doves continue to show a strong population decline; territories were more likely to be retained in areas with more nesting habitat, and more suitable foraging habitat. Aim To determine which features of farmland in England are important for retaining Turtle Dove territories Methods Fifty-eight grid squares with recent records of territorial Turtle Doves were resurveyed, and squares retaining Turtle Dove territories compared with those from which Turtle Doves had been lost. Results Turtle Dove territories were detected in 48% of squares resurveyed. When correcting for the 70% detection rate of the survey methodology, territories were present in 66% of squares surveyed suggesting a 34% decline over a 2-year period. Established scrub and hedgerows>4 m tall positively influenced Turtle Dove presence and abundance, as did standing water. Bare ground and fallow had positive effects on Turtle Dove abundance whereas grazed land negatively impacted abundance. Conclusion The positive effects of area of established scrub and volume of large hedgerows are likely to represent a declining density of birds selecting the best quality nest sites. We suggest instead that foraging habitat may be limiting distribution. © 2012 Copyright British Trust for Ornithology.
Watson H.,University of Glasgow |
Watson H.,Lund University |
Bolton M.,Center for Conservation Science |
Monaghan P.,University of Glasgow
Journal of Experimental Biology | Year: 2015
Conditions experienced during early life can have profound consequences for both short- and long-term fitness. Variation in the natal environment has been shown to influence survival and reproductive performance of entire cohorts in wild vertebrate populations. Telomere dynamics potentially provide a link between the early environment and long-term fitness outcomes, yet we know little about how the environment can influence telomere dynamics in early life.We found that environmental conditions during growth have an important influence on early-life telomere length (TL) and attrition in nestlings of a long-lived bird, the European storm petrel Hydrobates pelagicus. Nestlings reared under unfavourable environmental conditions experienced significantly greater telomere loss during postnatal development compared with nestlings reared under more favourable natal conditions, which displayed a negligible change in TL. There was, however, no significant difference in pre-fledging TL between cohorts. The results suggest that early-life telomere dynamics could contribute to the marked differences in life-history traits that can arise among cohorts reared under different environmental conditions. Early-life TL was also found to be a significant predictor of survival during the nestling phase, providing further evidence for a link between variation in TL and individual fitness. To what extent the relationship between early-life TL and mortality during the nestling phase is a consequence of genetic, parental and environmental factors is currently unknown, but it is an interesting area for future research. Accelerated telomere attrition under unfavourable conditions, as observed in this study, might play a role in mediating the effects of the early-life environment on later-life performance. © 2015. Published by The Company of Biologists Ltd.
Masden E.A.,University of the Highlands and Islands |
McCluskie A.,Center for Conservation Science |
Owen E.,Center for Conservation Science |
Langston R.H.W.,Center for Conservation Science
Marine Policy | Year: 2015
As marine renewable energy applications are increasing in the UK, environmental and cumulative impacts and their assessments are receiving considerable attention. The uncertainty, particularly surrounding cumulative impacts, however remains high and is becoming a cause of delay in the consenting process. This study examines the sources of uncertainty in environmental impact assessments and provides recommendations as to how these may be reduced, using the example of birds and wind farms. In the assessment of environmental impacts, uncertainty not only enters through the availability of empirical data but also data collection and analysis methods, linguistics and policy frameworks. Identifying and quantifying sources of uncertainty in environmental and cumulative impact assessments is critical to facilitating the development of an environmentally sustainable offshore wind industry. © 2014 Elsevier Ltd.
Buckingham D.L.,Center for Conservation Science |
Giovannini P.,Center for Conservation Science |
Peach W.J.,Center for Conservation Science
Agriculture, Ecosystems and Environment | Year: 2015
Grass fodder crops are attractive nesting habitats for a suite of declining farmland bird species that nest in taller grass swards. Multiple, early silage harvests cause substantial losses of nests and flightless fledglings, making this widespread crop an influential population sink in temperate farmland. We measured the effects of two simple conservation interventions (raised cutting heights and delayed mowing) designed to increase the reproductive output of a multi-brooded passerine (skylark Alauda arvensis). Annual reproductive output of independent juveniles (fecundity) was quantified using a stochastic re-nesting model that allowed us to investigate the impacts of a wide range of potential management interventions (varying cutting heights, dates and machinery) at minimal cost.Under typical silage management mean skylark fecundity was only 13-17% of the level required for metapopulation stability (the replacement rate). 12-54% of nests and 28-44% of fledglings survived a typical silage harvest with most losses caused by abandonment of nests covered by cut grass, crushing by wheels or predation soon after mowing. Delaying mowing increased fecundity, but only up to a maximum of 44% of the replacement rate. Raising cutting heights had a negligible impact on fecundity. Asynchrony between nesting attempts (due to predation, starvation and protracted delays between nesting attempts) resulted in few attempts taking place when they could benefit from the interventions. In the absence of mowing, fecundity was only 47% of the replacement rate, due to low reproductive output per nesting attempt, while simulations showed that increasing output per nest would have the largest impact on fecundity. Conservation effort should focus on providing alternative high fecundity breeding and foraging habitats at the landscape scale, to counteract silage fields' action as a sink for skylark populations in livestock-farming areas. These conclusions are likely to apply to other multi-brooded ground-nesting species. © 2015 Elsevier B.V.