Wildlife and Landscape Science News
Spring 2008
Wildlife Populations
- Red Knot Population Declines to Less Than 15,000
- Population Modelling for Ivory Gulls Yields Alarming Results
- Seabird Ecology Report Pending for the North Atlantic
- Reptile Ecology and Conservation Overview Available for Canada
Habitats and Ecosystems
- Murre Dive Characteristics Linked with Diet Change in Arctic Marine Ecosystem
- Landscape Changes Documented for Rural Southern Québec
- Maintaining Forest Biodiversity During Recovery from Mountain Pine Beetle Outbreaks
- Does Agricultural Policy in the Prairie Pothole Region Influence Nest Success of Ducks?
Health Effects of Toxics
- State of the Science Explored: Wildlife Exposure to Mercury
- Dramatic Acceleration in Trends of Flame Retardants in Great Lakes Gulls
About this e-news
Wildlife Populations
> Red Knot Population Declines to Less Than 15,000
The Red Knot population (Calidris canutus rufa) that spends the northern winter on the tip of South America has suffered another decline of 15%. The population is now estimated at 14,800 and is not yet showing signs of recovery.
COSEWIC has recommended this population for listing (Endangered) on Schedule 1, the official list of wildlife species at risk. The species will be proposed for listing in 2009 following extended consultation. Aerial surveys conducted each winter by Guy Morrison and Ken Ross provided the data documenting the population’s decline by almost 70% from over 50,000 in 2000.
In 2007, during northward migration, some 1,300 dead knots were discovered on Uruguay beaches. This and other challenges along their 16,000-km journey have devastated the vulnerable population. Most importantly, the shorebirds face insufficient feeding each spring on the beaches of New Jersey. The knots rest in Delaware Bay where they consume the eggs of once-plentiful horseshoe crabs to fuel the flight to their Arctic breeding grounds. Overfishing in the 1990s decimated the crab population and, subsequently, many underfed birds died while migrating or lacked the strength for successful nesting in the Arctic.
Recently, the governor of New Jersey signed a law (March 2008) banning the harvest of horseshoe crabs until both populations reach sustainable levels, as determined by the U.S. Fish and Wildlife Service.
Guy Morrison plays a prominent role in the Wildlife Conservation Society’s International Red Knot Project.
Contact: Dr. Guy Morrison (613) 998-7296
> Population Modelling for Ivory Gulls Yields Alarming Results
Results of a population viability analysis for Ivory Gulls (Pagophila eburnea) in Canada project the possible extirpation of the species over much of its breeding range in the next 10 years.
The status of Ivory Gulls, a rare species that breeds at remote sites in the high Arctic, was assessed to determine whether Canadian breeding populations will persist into the near future. COSEWIC has recommended this population for “uplisting” on Schedule 1, the official list of wildlife species at risk, from Special Concern to Endangered. Recent declines were shown previously by Gilchrist and Mallory (2005: Biol. Cons. 121: 303-309).
As most of the data were collected at the colony level, the evaluation used techniques based on colony site dynamics rather than traditional demographic rates. The analysis used survey data of breeding colonies from 2001 to 2006 – covering most of the known breeding range – using a starting population of 225 pairs at the 24 sites. The projected population declined to approximately 30 pairs in just eight years. A more traditional population viability analysis was conducted for the large Seymour Island colony: although declining, this site is not at immediate risk of extinction.
The analysis demonstrates how colony or site-specific data can be used to effectively model population viability and persistence of colonial birds. Results were published in the journal, Avian Conservation and Ecology:
Robertson, G. J., H. G. Gilchrist, and M. L. Mallory. 2007. Colony dynamics and persistence of Ivory Gull breeding in Canada. Avian Conservation and Ecology - Écologie et conservation des oiseaux 2(2): 8.
Contact: Dr. Greg Robertson (709) 772-2778 for information on the analysis / Dr. Grant Gilchrist (613) 998-7364 or Mark Mallory (867) 975-4637 for information on Ivory Gulls
> Seabird Ecology Report Pending for the North Atlantic
The International Council for the Exploration of the Sea (ICES), an intergovernmental body, coordinates and promotes marine research in the North Atlantic for an international community of some 1,600 marine scientists. The Working Group on Seabird Ecology is preparing an annual report on its 2008 focal points, which will be available online:
- effects of climate change on North Atlantic seabirds
- North Atlantic seabirds and bycatch in long-line fisheries
- ecological issues linked to the circulation of parasites and pathogens within seabird populations
Highlights of the 2007 report include: a review of current approaches to identifying protected areas for seabirds (demonstrated with case studies); continued development of a concept for a comprehensive seabird monitoring program; a new section on the use of seabirds as biomonitors of marine environment change; and a review of evidence of climate-related changes for seabirds in the OSPAR Maritime Region (north-east Atlantic) based on changes in distribution, reproductive success, survivorship and different phenological aspects. Download the 2007 Report of the Working Group on Seabird Ecology. Download the ICES meeting calendar for information on working groups .
John Chardine is an official Canadian delegate on the working group.
Contact: Dr. John Chardine (506) 364-5046
> Reptile Ecology and Conservation Overview for Canada
A new volume describes the ecology and conservation issues for the 46 species of reptiles in Canada. Ecology, Conservation, and Status of Reptiles in Canada, edited by Carolyn Seburn and Christine Bishop of Environment Canada, depicts the current view of reptiles that occur in Canada and Canadian marine waters, and the difficulties faced in their conservation.
The 11 chapters are contributed by prominent Canadian herpetologists and include overviews of the major groups (i.e., turtles, marine turtles, lizards and snakes) and discussions of issues and conservation tools.
This is the second in the Herpetological Conservation series published by The Canadian Amphibian and Reptile Conservation Network and the Society for the Study of Amphibians and Reptiles.
Contact: Dr. Christine Bishop (604) 940-4671 or Carolyn Seburn (819) 934-3963
Habitats and Ecosystems
> Murre Dive Characteristics Linked with Diet Change in Arctic Marine Ecosystem
Studies of feeding ecology in Thick-billed Murres focus in part on foraging behaviour at the Coats Island breeding colony on northern Hudson Bay. This colony is unusual in that chicks are fed a broad diet including fish of several species, crustacea and squid. As the murres’ diet changes in response to changes in ice cover, observations using data loggers provide a valuable tool for tracking changes in marine ecosystems where marine food webs are not well-known.
Small data loggers were attached to the birds' legs each summer over several years. Data collected established foraging range and diving depth and shape (straight down and up, or flat-bottomed with a period of searching at a specific depth) for several hundred birds. This information identified diet items with combinations of dive characteristics, allowing prey identification from logger data alone and reducing the need for prolonged observations in diet studies.
Results were published in the journals, Canadian Journal of Zoology and Marine Ecology Progress Series:
Elliott, K.H., G.K. Davoren and A.J. Gaston. 2007. The influence of buoyancy and drag on the dive behaviour of an Arctic seabird, the Thick-billed Murre. Canadian J. Zoology 85: 352-361.
Elliott, K., K. Woo, A.J. Gaston, S. Benvenuti, L. Dall'Antonia and G. Davoren. 2008. Foraging behaviour of an arctic seabird indicates prey type. Marine Ecology Progress Series 354: 289-303.
View an online video from CBC TV’s The National, A Tale of Two Bird Colonies, which features Coats Island and Prince Leopold Island. Tony Gaston is interviewed by Peter Mansbridge about his 30-plus years of field research, including a discussion of the role of birds as barometers of change.
Contact: Dr. Tony Gaston (613) 998-9662
> Landscape Changes Documented for Rural Southern Québec
Wildlife habitats in southern Québec have changed drastically in recent decades, mainly as a result of agricultural and urban expansion. Major changes in land use, land cover and landscape have now been documented in the St. Lawrence Lowlands and Appalachian ecoregions using Landsat images from 1993 and 2001.
A further sample of 900 square kilometres (36 plots each measuring 5x5 kilometres) was interpreted along a gradient of agricultural intensity in the St. Lawrence Lowlands ecoregion using aerial photos from <1950, 1965 and 1997. The aerial photos were used to quantify changes over a longer period of landscape patterns, land cover, and small habitats (hedgerows, riparian habitats) not visible on Landsat images.
A shift in major agricultural classes was observed in the St. Lawrence Lowlands where forage crops and pastures were converted into annual crops in areas under high-intensity cultivation. Woodlot fragmentation did not change through time. Urban coverage increased throughout the ecoregion at the expense of annual and perennial crops, forests and old fields. Road density increased markedly from 1950 to 1997, whereas drainage ditch and watercourse densities were reduced. Treed hedgerow density first declined between 1950 and 1965 before experiencing a sharp increase. Few changes were observed in agricultural land cover classes in the agro-forested landscapes of the Appalachian ecoregion. Land abandonment was observed in some areas now covered with forests.
Results were published in the Canadian Wildlife Service Technical Report series and Le Naturaliste Canadien, including discussion of observed changes in land cover, potential impacts on biodiversity, scenarios regarding possible future land cover changes, and the importance of protecting the integrity of wildlife habitats in these agricultural landscapes:
Latendresse, C., B. Jobin, C. Maisonneuve, A. Sebbane and M. Grenier. 2008. Changements de l’occupation du sol dans le Québec méridional entre 1993 et 2001. Le Naturaliste Canadien 132: 14-23.
Latendresse, C., B. Jobin, A. Baril, C. Maisonneuve, C. Boutin and D. Côté. 2008. Dynamique spatio-temporelle des habitats fauniques dans l’écorégion des Basses terres du fleuve Saint-Laurent, 1950-1997. Série de rapports techniques no 494, Environnement Canada, Service canadien de la faune, région du Québec, Québec, 83 p. et annexes.
Jobin, B., C. Latendresse, C. Maisonneuve, A. Sebbane and M. Grenier. 2007. Changements de l’occupation du sol dans le sud du Québec pour la période 1993-2001. Série de rapports techniques nº 483, Environnement Canada, Service canadien de la faune, région du Québec, Sainte-Foy, Québec. 112 p. et annexes.
Contact: Benoît Jobin (418) 649-6863
> Maintaining Forest Biodiversity During Recovery From Mountain Pine Beetle Outbreaks
Mountain pine bark beetle (Dendroctonus ponderosae) is a major natural disturbance structuring North America’s mature conifer stands. The largest beetle outbreak recorded for North America is spreading east and north, with resulting declines in the health of western forests. Insights into effects on wildlife populations are essential to conserve and manage those forests during recovery.
Since 1995, before the outbreak, field research has monitored forest wildlife and habitat conditions in the Cariboo-Chilcotin region of interior British Columbia. The study has provided an opportunity to track habitat and wildlife shifts during the outbreak and ensuing forest salvage activities. For example, nuthatches and chickadees currently have very low populations.
The mixed forests of interior British Columbia support more than 185 vertebrate species, about 24% of which are birds and mammals known as cavity-nesters. These species require dead and dying conifers for nesting, roosting and foraging. Cavity-nesters thrived early in the outbreak due to the abundance of beetles.
Some “beetle-eaters” may moderate the onset, distribution, duration or intensity of outbreaks. More than 20 bird species consume beetle larvae and/or adults. For example, woodpeckers destroyed 24-98% of beetles when beetle populations were at medium to high levels. Woodpeckers continue to thrive but are expected to decline sharply.
Beetle attacks are variable in intensity and distribution. Maintaining an irregular pattern is key to biodiversity protection. Retention patches should include dead and dying trees, especially aspen and large conifers. The patches should be at least 1 ha in size and include larger patches (>10 to 50 ha) to support mature-forest species.
Results, discussion and recommendations for forest managers are available:
Biodiversity Maintenance and Conservation in Post-Epidemic MPB Forests in Interior BC. Authors: Kathy Martin, Mark Drever and Andrea Norris. PowerPoint.
Norris, A. R. and K. Martin. 2008. Mountain pine beetle presence affects nest patch choice of red-breasted nuthatches. Journal of Wildlife Management 72(3): 733-737. [DOI: 10.2193/2006-409]
Drever, M.C., K.E.H. Aitken, A.R. Norris and K. Martin. 2008. Woodpeckers as reliable indicators of bird richness, forest health, and harvest. Biological Conservation 141(3): 624-634. [DOI: 10.1016/j.biocon.2007.12.004]
Davidson, P., W. Easton and K. Martin. 2007. Beetlemania in British Columbia. Bird Watch Canada 39: 8-11.
Martin, K., A.R. Norris and M. Drever. 2006. Effects of bark beetle outbreaks on avian biodiversity in the British Columbia Interior. Implications for critical habitat management. BC Journal of Ecosystems and Management 7(3): 10-24.
Contact: Dr. Kathy Martin (604) 940-4667
> Does Agricultural Policy in the Prairie Pothole Region Influence Nest Success of Ducks?
The Prairie Pothole Region stretches from central Alberta south-east to Iowa. The area is rich in wetlands which remain crucial for wildlife – especially waterfowl and other wetland species. In the past 100 years, agricultural expansion has eliminated, fragmented and degraded habitats such as wetlands, native grasslands and woodlands.
The United States (U.S.) addressed some aspects of upland habitat loss through the 1985 U.S. Farm Bill, which provided economic incentives to reduce production on marginal farmland and benefited nesting waterfowl and other wildlife. Canada does not have equally comprehensive legislation, although some detrimental agricultural subsidies (e.g., grain transportation) were removed in the 1990s. This difference in policy approach suggests that benefits to waterfowl in Canada should lag behind the U.S.
To test this idea, duck nest success in the U.S. and Canada was compared to assess long-term changes in each country, and to relate nest success to cropping intensity and wetland density. Overall, mean duck nest success increased only slightly in Canada from pre-1970s until the end of the study period in 2005, whereas mean nest success increased in the U.S. during the 1990s. Nest success in both countries was negatively related to cropping intensity, and was positively related to wetland density only in Canada.
These findings are consistent with suggestions that agricultural policy which encourages large-scale permanent upland cover positively influences duck reproductive success. Results also suggest that the benefits from increased perennial cover in Canada would be better realized if accompanied by strong measures to conserve and restore wetlands.
Results were published in the journal, Avian Conservation and Ecology:
Drever, M. C., T. D. Nudds and R. G. Clark. 2007. Agricultural policy and nest success of prairie ducks in Canada and the United States. Avian Conservation and Ecology - Écologie et conservation des oiseaux 2(2): 5.
Contact: Dr. Bob Clark (306) 975-4110
Health Effects of Toxics
> State of the Science Explored: Wildlife Exposure to Mercury
Three times more mercury falls from the atmosphere on average today than before the Industrial Revolution despite the steep reduction in industrial use of mercury in North America. In recent years, ecological risk assessment associated with elevated exposure to methylmercury has revealed increasingly subtle yet biologically important effects in fish and wildlife, including behavioural, neurochemical, hormonal and reproductive changes. The potential for population-level impacts are also being assessed for some species.
Leading mercury scientists collaborated as part of the Eighth International Conference on Mercury as a Global Pollutant (August 2006). The results were published in a special issue of the journal, Ambio, including a conference declaration and synthesis papers on mercury pollution. A special issue of the journal, Ecotoxicology, presents the state of the science specifically for toxicology of methylmercury in wildlife, selected by guest editors Tony Scheuhammer and Mark B. Sandheinrich (University of Wisconsin-La Crosse).
AMBIO: A Journal of the Human Environment / Mercury Pollution Volume 36, Issue 1 (February 2007)
Scheuhammer, A.M., M.W. Meyer, M.B. Sandheinrich and M.W. Murray. 2007. Effects of Environmental Methylmercury on the Health of Wild Birds, Mammals, and Fish. Ambio 36: 12-19.
ECOTOXICOLOGY / Special Issue on Effects of Methyl Mercury on Wildlife Volume 17, Number 2 (February 2008)
Scheuhammer, A.M. and M.B. Sandheinrich. 2008. Recent advances in the toxicology of methylmercury in wildlife. Ecotoxicology 17(2): 67-68.
Burgess, N.M. and M. Meyer. 2008. Methylmercury exposure associated with reduced productivity in common loons. Ecotoxicology 17(2): 83-91.
Scheuhammer, A.M., N. Basu, N.M. Burgess, J.E. Elliott, G.D. Campbell, M. Wayland, L. Champoux and J. Rodrigue. 2008. Relationships among mercury, selenium, and neurochemical parameters in common loons (Gavia immer) and bald eagles (Haliaeetus leucocephalus). Ecotoxicology 17(2): 93-101.
Read more about The Changeable State of Mercury Pollution on Environment Canada’s S&T Website.
Contact: Dr. Tony Scheuhammer (613) 998-6695
Dramatic Acceleration in Trends of Flame Retardants in Great Lakes Gulls
Analysis of Herring Gull eggs collected from sites across the Great Lakes between 1982 and 2006 shows changes in the presence of an important class of brominated flame retardants, polybrominated diphenyl ethers (PBDEs), used widely in manufacturing. Changes were evident in the distribution pattern within the region, the type of PBDE congeners (individual PBDEs that differ by the number and position of bromine atoms on the same molecule base, i.e., a diphenyl ether) found, and the quantity of PBDEs deposited in the eggs over the period. PBDE concentrations and congener pattern trends have dramatically changed since 1995.
The study used pooled samples of Herring gull (Larus argentatus) eggs from seven colonies spanning the Laurentian Great Lakes. As a bioindicator species, these birds’ eggs have been monitored since the early 1970s because traces of persistent chemicals form metabolically in their bodies and/or bioaccumulate from their diet and are transferred to their eggs.
Particularly noteworthy is the rapid increase in the levels of decaBDE (BDE-209) found, as well as octa- and nona-BDE degradation products. DecaBDE is a current-use, commercial formulation of an additive flame retardant composed almost entirely of BDE-209. From 1982 to 2006, the BDE-209 doubling times ranged from 2.1 to 3.0 years, whereas for octaBDEs and nonaBDEs, the mean doubling times ranged from 3.0 to 11 years and 2.4 to 5.3 years, respectively. PBDE congeners derived mainly from pentaBDE and octaBDE mixtures (e.g., BDE-47, BDE-99 and BDE-100) showed rapid increases up until 2000.
While BDE-209 does not fit the pervasive criteria as a persistent and bioaccumulative substance, it is clearly of increasing concern in Great Lakes Herring gulls and provides evidence that control of decaBDE formulations is warranted.
L.T. Gauthier, C.E. Hébert, D.V. Chip Weseloh and R.J. Letcher.2008. Dramatic changes in the temporal trends of polybrominated diphenyl ethers (PBDEs) in herring gull eggs from the Laurentian Great Lakes: 1982-2006. Environ. Sci. Technol. 42(5): 1524-1536.
Read more about Thirty Years of Monitoring Great Lakes Herring Gulls on Environment Canada’s Website.
Contact: Dr. Robert Letcher (613) 998-6696
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