Effects of Summer Grazing by Caribou on Composition and Productivity of Vegetation: Community and Landscape Level

Abstract

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Opposing plant community responses to warming with and without herbivores

“…Caribou and reindeer (Rangifer tarandus), for instance, can promote expansion and productivity of graminoids while constraining biomass of deciduous shrubs such as dwarf birch (Betula nana) and willow (Salix glauca) (21,22,(25)(26)(27). Such opposing responses to herbivory of plant species belonging to different functional groups may contribute to changes in plant community composition and C-sequestration potential of ecosystems in response to climate change.…”

A conceptual model for migratory tundra caribou to explain and predict why shifts in spatial fidelity of breeding cows to their calving grounds are infrequent

“…For example, the George and Leaf River herds have high amplitude changes in herd size and shifts in calving distribution up to 400 km (Bergerud et al, 2008;Couturier et al, 2009). Between 1986 and 2003, the George River herd peaked in size at about 776 000 (±104 000) in 1993 before decreasing (Crete & Huot 1993, Manseau et al, 1996, Couturier et al, 2009 while the Leaf River herd probably peaked in 2001 and then started to decline (Couturier et al, 2009). When both the George River and Leaf River herds were increasing in size, their calving grounds directionally shifted north of the tree line.…”

Productivity factors of the Finnish semi-domesticated reindeer (Rangifer t.tarandus) stock during the 1990s

“…Overgrazing of summer pastures therefore affects the quantity and quality of summer fodder available for reindeer or caribou (see Ouellet et al 1994;Manseau et al, 1996;Crête & Doucet, 1998). Poor summer food availability causes reduction of body weight of reindeer and may then also reduce calf production.…”

“…It is likely that in the same way as in winter pastures, productivity of summer fodder in the most important summer range areas can be manipulated by adjusting the long-term grazing pressure (see for example Tolvanen et al, 1992;1993;Ouellet et al, 1994;Manseau et al, 1996;Crête & Doucet, 1998;Alpe et al, 1999). Varying weather and snow conditions, to which reindeer management always has to adapt, form one essential element in the productivity and availability of fodder plants.…”