Robert Lenthall Jefferies Collection
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When Bob Jefferies died unexpectedly in 2009, Canada lost one of its most important Arctic biologists at a vital and significant time. Bob was a professor at the University of Toronto from 1974 to 2009 in the Botany Department, which later became the Ecology and Evolutionary Biology Department.
This sub-community in the Churchill Communities of Knowledge digital archive celebrates Bob's life and research legacy. From 1978 to 2009, Bob and his students carried out field research on the effects of herbivory on salt-marsh vegetation by lesser snowgeese at La Pérouse Bay, on the shores of Hudson Bay, east of Churchill, Manitoba. Bob is seen above, at Camp Finney (Nestor 2) during spring melt in June 1983. Bob also did research with his students in other parts of the Churchill region, and elsewhere in the Arctic.
Bob not only worked in northern Canada. He carried out research in California, where he was a post-doc with Emmanuel Epstein, at University of California at Davis, from 1962-64, and a Distinguished Visiting Professor at the Bodega Marine Laboratory (UC Davis) in 2002-03. Bob also studied salt-marshes in the United Kingdom and Europe.
Digitized versions of many of Bob's research accomplishments can be found in this collection, including his students' theses and dissertations, along with images and other forms of media.
Correspondence and information relating to Bob's participation in the Intergovernment Panel on Climate Change is also lodged here.
The programme from Bob's Memorial Celebration, held on November 9th 2009, can be found here
Recent Submissions
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Taxonomic status of diploid Salicornai europaea (s.L.) (Chenopodiaceae) in northeastern North America.
(01/03/2013)The taxonomic status of diploid Salicornia europaea L. (s.1.) in northeastern North America has been evaluated based on morphological and electrophoretic variation within and between populations. Populations of two European ... -
Robert Jefferies with a baby Arctic Fox
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Researchers on the top of the McConnell esker
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The biology of the annual Salicornia europaea agg. at the limits of its range in Hudson Bay.
(NRC Research Press, 1983)The biology of a marginal population of the annual Salicornia europaea agg. has been examined at La Pérouse Bay, Manitoba, on the shores of Hudson Bay. Plants were confined to south-facing sites which became hypersaline ... -
Seasonal partitioning of resource use and constraints on the growth of soil microbes and a forage grass in a grazed Arctic salt-marsh
(Springer Verlag, 2009)Seasonal growth responses of plants and soil microorganisms to additions of nitrogen (N), phosphorus (P) and carbon (C) were examined in goose-grazed and exclosed plots in an Arctic salt marsh. Plants showed strong growth ... -
Soil microbial and nutrient dynamics in a wet Arctic sedge meadow in late winter and early spring
(Elsevier, 2006)Microbial activity is known to continue during the winter months in cold alpine and Arctic soils often resulting in high microbial biomass. Complex soil nutrient dynamics characterize the transition when soil temperatures ... -
Is the decline of soil microbial biomass in late winter coupled to changes in the physical state of cold soils?
(Elsevier, 2010)During winter when the active layer of Arctic and alpine soils is below 0 °C, soil microbes are alive but metabolizing slowly, presumably in contact with unfrozen water. This unfrozen water is at the same negative chemical ... -
The role of lesser snow geese in positive, degenerative feedback processes resulting in the destruction of salt-marsh swards.
(1993)A positive feedback cycle between soil salinity and graminoid growth, triggered by intensive grazing and grubbing by geese, is proposed to account for the loss of graminoid vegetation in an arctic salt marsh (La Pérouse ... -
Allochthonous inputs: integrating population changes and food-web dynamics
(Elsevier, 2004)Most ecosystems are recipients of allochthonous materials that enhance in situ productivity. Recent theoretical and empirical studies suggest that low to moderate inputs can stabilize food webs. However, depending on the ... -
Robert L Jefferies Virtual Issue
(12/11/2012) -
Soluble carbohydrate content of shoots of Arctic wetland plants that are consumed by lesser snow geese
(NRC Research Press, 2008)We recorded seasonal changes in the total amounts of soluble carbohydrates in shoots of salt- and fresh-water coastal plants at La Pérouse Bay, northern Manitoba, to determine whether adult snow geese and their goslings ... -
Goose-induced Changes in Vegetation and Land Cover between 1976 and 1997 in an Arctic Coastal Marsh
(Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, 2005)Since the 1970s, a breeding colony of lesser snow geese (Chen caerulescens caerulescens L.) at La Pérouse Bay, Manitoba, has grown 8% annually. This increase has led to significant loss of plant cover in all major salt- ... -
Patterns and Processes of Species Diversity in Fragmented Northern Hardwood Forests.
(Toronto : University of Toronto, 2001)Twenty-four upland hardwood forests were examined to determine the influence of plant dispersal and environmental heterogeneity on the composition and richness of species in the forest understory. Patterns in the dispersal ... -
Soil Microbial and Nutrient Dynamics During Late Winter and Early Spring in Low Arctic Sedge Meadows
(Toronto : University of Toronto, 2010)Microbial activity occurs year-round in Arctic soils, including during the winter when soils are frozen. From 2004 to 2008 I monitored soil microbial and nutrient dynamics in low Arctic wet and dry sedge meadows near ... -
Seed and vegetation dynamics in undamaged and degraded coastal habitats of the Hudson Bay lowlands.
(Ottawa : National Library of Canada = Bibliotheque nationale du Canada, 2000)Grubbing and grazing by increasing numbers of lesser snow geese (Anser caerulescens caerulescens) have led to loss of vegetation and soil degradation in salt marshes and on beach ridges. These changes have had a deleterious ...
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