Wildlife and Landscape Science News

Wildlife Populations

> Evidence for Conserving Biofilm for Higher-level Organisms

A study of the foraging behaviour of Western Sandpipers provides evidence for conserving biofilm found on mud flats and other aquatic environments. This is the first report of biofilm feeding for any higher vertebrate, revealing that biofilm accounts for 45 to 59% of the sandpipers’ total diet.

The study was conducted at the Roberts Bank mud flats on the Fraser River estuary in British Columbia. Each spring, more than two million sandpipers feed on the flats as they migrate northward. Individual grazing rates are estimated at seven times body mass per day and flock sizes into the tens of thousands.

The physical and biological processes that maintain biofilm are important to shorebird and intertidal conservation. Biofilm is a thin, dense layer of microbes, organic detritus and sediment in a mucous-like matrix. The research team used video images of feeding, stomach contents, stable isotope techniques, and energy budget models to identify the contribution of biofilm and associated organisms to the diet of Western Sandpipers.

Threats to biofilm from coastal development, changing hydrodynamic processes or additional grazing pressures from invasive species are not currently considered in environmental assessment procedures. This study provides evidence that conservation of biofilm should be an explicit consideration not only for native invertebrate species but also higher trophic level organisms where food sources overlap. Adverse cascading trophic interactions could be triggered by direct competition between higher vertebrates and invertebrates, leading to decreases in biofilm availability as a food for shorebirds, potentially contributing to population-level declines.

Kuwae, T., P.G. Beninger, P. Decottignies, K.J. Mathot, D.R. Lund and R.W. Elner. 2008. Biofilm grazing in a higher vertebrate: the Western Sandpiper, Calidris mauri. Ecology 89(3): 599-606.

Bob Elner was interviewed about the study by the Victoria Times-Colonist: Snot-Like Mud Coating Makes Roberts Bank Unique for Sandpipers

Contact: Dr. Bob Elner (604) 940-4674

> Can Ducks Function as Habitat Quality Indicators for Grassland Birds in Southern Saskatchewan?

Bird Conservation Regions (BCR) provide a common geographic basis for initiatives that may benefit all bird species. BCR 11 is on the Canadian Prairies and covers the prairie pothole region of Alberta, Saskatchewan, Manitoba and the north-central United States. In this region, loss and degradation of natural habitats contribute to the decline of grassland birds.

A two-year study was conducted to determine whether ducks (Northern Pintail in particular) can function as an indicator or umbrella guild for overall breeding habitat quality for other grassland birds. Currently, digital mapping that integrates long-term duck population and land-use data guide conservation program delivery. A greater understanding of the relationships between ducks and other grassland birds would enhance multi-species conservation planning.

The study compared grassland bird species richness and relative abundance among areas of low, moderate and high predicted waterfowl breeding densities in southern Saskatchewan. Overall, duck and other grassland bird species richness and abundance were moderately correlated; ducks were somewhat successful as an indicator or umbrella guild.

This approach may facilitate the initial selection of areas of high conservation value for multiple grassland bird species, but will not directly benefit the development of priority species conservation plans. Adequate critical habitat for several priority species may not be protected if conservation is focused only in areas of moderate to high wetland density because large tracts of contiguous, dry grassland habitat (e.g., pasture) occur infrequently in high-quality duck habitat.

Skinner, S.P. and R.G. Clark. 2008. Relationships between duck and grassland bird relative abundance and species richness in southern Saskatchewan. Avian Conservation and Ecology - Écologie et conservation des oiseaux 3(1): 1. 

Contact: Dr. Bob Clark (306) 975-4110

> Using Stable Isotopes in Migration Research

A new volume presents an overview of the current knowledge of stable isotopes in migration research. Tracking Animal Migration with Stable Isotopes is edited by Keith Hobson and Len Wassenaar of Environment Canada. Their expertise and experience in this fast-growing field combine to make the volume accessible and clear for other researchers and for ecologists, animal behaviourists and wildlife managers.

Many questions in animal biology require tracking of animal movements by using multi-disciplinary and technological innovations. Over the past decade, intrinsic chemical markers have become especially key in the study of migration. This volume includes information on application of methods, and study design and analysis.

This is the second in a Terrestrial Ecology series from Academic Press. Also available as a ScienceDirect e-book.

Read more about stable isotope research:

• Cougar's movements betrayed by claw analysis (Nature.com)
• Secrets of Wildlife Migration Revealed through a Forensic “Isotopic Tag” (Environment Canada)

Contact: Dr. Keith Hobson (306) 975-4102 or Dr. Len Wassenaar (306) 975-5747

Health Effects of Toxics

> Tracking Pollutants and Their Effects in Top Arctic Predators

Arctic ecosystems are currently undergoing unprecedented changes in climate. In addition, organic and metal pollutants are transported north from lower latitudes into the Arctic by prevailing winds and, to a lesser degree, by ocean currents. Resource extraction in the Arctic has also increased the concentration of some metals.

The identity, fate, trends and effects of organic and metal pollutants are the subject of international collaborative research projects examining top predators, specifically mammals (e.g., polar bears, sled dogs) and seabirds (e.g., glaucous gulls), for exposure to pollutants and potential health effects.

The research team includes Robert Letcher and Derek Muir of Environment Canada and Christian Sonne and Rune Dietz of Denmark’s National Environmental Research Institute. In the present study component, the research team analyzed elements (e.g., cadmium, arsenic, mercury) in the livers of polar bears collected by hunters in Canada, Alaska and Greenland, between 1994 and 2002.

The purpose was to assess geographic distributions of elements and make comparisons between current and older data. Geographical trends, similar to those observed in the early 1980s, were seen in a number of elements including mercury. Significant geographic differences were revealed in the concentrations of some essential and non-essential elements.

These top predators are excellent sentinels of Arctic environmental pollutants because they are long lived, circumpolarly distributed and feed mainly on seals (with some populations preferring ringed seals). Previous research has shown that the accumulation of organohalogen contaminants, such as PCBs, could be affecting polar bears. Examples of effects include influence on reproductive success and immune response.

These concentrations may pose a long-term health risk for polar bears. However, it may be more immediately significant that contaminant burdens pose additional stress on a species already facing potential declines due to short-term climate changes.

Results were published in Environmental Pollution:

Rush, S.A., K. Borgå, R. Dietz, T. Evans, D.C.G. Muir, R.J. Letcher, R.J. Norstrom and A.T. Fisk. 2008. Geographic distribution of select elements in the livers of polar bears (Ursus maritimus) from Greenland, Canada and the United States. Environ. Pollut. 153(3): 618-626. [doi:10.1016/j.envpol.2007.09.006]

Contact: Dr. Robert Letcher (613) 998-6696 or Dr. Derek Muir (905) 319-6921

> New Method Detects Contaminant-induced Alterations of Gene Expression in Wildlife

A new method to identify gene targets, Fluorescent RNA Arbitrarily Primed PCR (FRAP-PCR), has been developed in the molecular toxicology laboratory at Environment Canada’s National Wildlife Research Centre (Ottawa). The method is described in a chapter of a new environmental genomics textbook. The chapter was written by Doug Crump and colleagues from Environment Canada.

FRAP-PCR has been used to identify novel gene targets in neuronal (see paper below) and hepatic avian cells, as well as brain and liver samples in species such as the herring gull, mallard duck and chicken. The technique offers an attractive approach for researchers trying to identify novel molecular mechanisms of action of various environmental contaminants in a wide range of species.

The textbook is available from Humana Press:

Crump, D., S. Chiu, V.L. Trudeau and S.W. Kennedy. 2008. Fluorescent RNA Arbitrarily Primed (FRAP) PCR - A new differential display approach to detect contaminant-induced alterations of gene expression in wildlife species. In Methods in Molecular Biology 410: Environmental Genomics (Martin, C., ed.). Humana Press (Totowa, NJ), pp. 15-27.

A paper in Toxicology in Vitro highlights the method and describes its application as a screening tool to identify polybrominated diphenyl ether (PBDE) effects on gene expression in chicken neuronal cells:

Crump, D., M.M. Jagla, S. Chiu and S.W. Kennedy. Detection of PBDE effects on mRNA expression in chicken (Gallus domesticus) neuronal cells using real-time RT-PCR and a new differential display method. Toxicol. in Vitro 22(5): 1337-1343. [doi:10.1016/j.tiv.2008.03.015]

Contact: Doug Crump (613) 998-7383

> Risk Assessment for Avian Predators in Cascades Forest District

Various techniques were used in recent decades to reduce timber losses from bark beetle outbreaks including an arsenic-based pesticide, monosodium methanearsonate (MSMA). As many as 700,000 MSMA-treated trees remain on the landscape in British Columbia’s forests.

A four-year study in the Cascades (Merritt) Forest District assessed the threat of MSMA to avian predators that feed directly on bark beetles. John Elliott and colleagues worked with Simon Fraser University and University of British Columbia to conduct field and laboratory research such as arsenic analysis of bark beetles, an index of woodpecker foraging, blood and feather sampling of birds to measure arsenic residues, and forest bird surveys in MSMA stands relative to untreated areas. This work provided evidence of a significant risk to woodpecker species and other insect-eating birds.

These results informed a collaborative forum, hosted by the British Columbia Ministry of Forests and Range, to develop a policy framework and recommendations to the Chief Forester on how to factor a landscape legacy of MSMA-treated trees into cutting and wildlife set aside regulations. The forum included government and industry foresters and biologists, and representatives from non-government organizations.

There are now North America wide restrictions on arsenic-based pesticides and MSMA is removed from the B.C. market.

Results were published in the Canadian Wildlife Service Technical Report series and scientific journals:

Morrissey, C.A., P.L. Dods and J.E. Elliott. 2008. PESTICIDE TREATMENTS AFFECT MOUNTAIN PINE BEETLE ABUNDANCE AND WOODPECKER FORAGING BEHAVIOR. Ecological Applications 18: 172-184.

Albert, C.A., T.D. Williams, W.R. Cullen, V. La, C.A. Morrissey and J.E. Elliott. 2008. Dose dependant uptake, elimination and toxicity of monosodium methanearsonate (MSMA) in adult Zebra Finches (Taeniopygia guttata). Environmental Toxicology and Chemistry 27(3): 605-611.

Albert, C.A., T.D. Williams, W.R. Cullen, V. Lai, C.A. Morrissey and J.E. Elliott. 2008. Tissue uptake, mortality and sub-lethal effects of monomethylarsonic acid (MMA (V)) in nestling Zebra Finches (T. guttata). Journal of Toxicology and Environmental Health 71(6): 353-360. [doi: 10.1080/15287390701738566]

Morrissey, C.A., C.A. Albert, P.L. Dods, W.R. Cullen, V.W.-M. Lai and J.E. Elliott. 2007. Arsenic accumulation in bark beetles and forest birds occupying mountain pine beetle infested stands treated with monosodium methanearsonate (MSMA). Environmental Science & Technology 41(4): 1494-1500.

Morrissey, C.A., P.L. Dods, C.A. Albert, W. Cullen, V. Lai, T.D. Williams and J.E. Elliott. 2006. Assessing forest bird exposure and effects from Monosodium Methanearsonate (MSMA) during the Mountain Pine Beetle epidemic in British Columbia. Canadian Wildlife Service Technical Report Series No. 460: 89 pp.

Contact: Dr. John Elliott (604) 940-4680

> Scientific Opinion: Risk Assessment for Birds and Mammals from Agricultural Pesticides

The European Food Safety Authority’s (EFSA) Guidance Document on Risk Assessment for Birds and Mammals is being revised by the Scientific Panel on Plant Protection Products and their Residues (PPR Panel). A core working group was established to provide a scientific opinion to the PPR Panel encompassing risk management issues.

The resulting Scientific Opinion on the Science behind the Guidance Document on Risk Assessment for birds and mammals (PDF) addresses approaches to risk assessment for birds and mammals to assess the risk of mortality and reproductive effects. The PPR Panel developed a first-tier assessment procedure for scenarios including different crops and different types of pesticide uses. Each scenario combines the ecological characteristics of exposed species with factors relevant to their exposure such as the type of crop and the formulation of the pesticide.

The EFSA published the scientific opinion on its website. Download the opinion summary, the opinion document and extensive related appendices that report on new approaches and analyses carried out in support of the opinion.

Pierre Mineau is a member of the core working group that developed the scientific opinion.

Contact: Dr. Pierre Mineau (613) 998-0518