Persistent Suppression in Dwarf Birch after Release from Heavy Summer Browsing by Caribou

Crête, Michel; Doucet, G. Jean

doi:10.2307/1552127

Cited by 44 publications

(40 citation statements)

References 26 publications

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“…The same kind of examples can be found in several Cervidae populations, such as reindeer, and caribou (Klein, 1968;Leader-Williams & Ricketts, 1982;Reimers, 1983;Skogland, 1983;1985;Post & Klein, 1999), red deer (Coulson et al, 1997), roe deer (Hewison et al, 1996) and moose (Sand et al, 1996;Hjeljord & Histøl, 1999). Heavily overgrazed plant communities may also need a very long time to recover to the optimal stage (Klein, 1987;Crête & Doucet, 1998;Kumpula et al, 2000).…”

Section: Discussionmentioning

confidence: 82%

“…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.…”

Section: Discussionmentioning

confidence: 99%

“…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.…”

Section: Discussionmentioning

confidence: 99%

“…Even though the ultimate reason for collapses in reindeer or caribou populations can be found in harsh snow and weather conditions in winter, the collapses are almost always preceded by the gradual deterioration of animal nourishment in pastures. The increasing herbivore population causes a slowly progressing, but continuous change in the composition, biomass and productivity of plant species on the most important pasture areas, especially in those plants which are most important as fodder for herbivores (Klein, 1968;Leader-Williams et al, 1987;Henry al., 1998;Crête & Doucet, 1998;Alpe et al, 1999). These vegetation changes may take place so gradually that their documentation over a period of years can prove very difficult (Wegener & OdaszAlbrigtsen, 1998).…”

Section: Introductionmentioning

confidence: 99%

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

Kumpula¹,

Colpaert

Nieminen³

2002

Ran

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Intensive reindeer grazing and the increase of other land use forms have caused a decline in the amount of arboreal (Alectoria, Bryoria spp.) and reindeer (Cladina spp.) lichens in the Finnish reindeer management area during the last few decades. Supplementary feeding of reindeer has increasingly compensated for the lack of natural winter fodder. The amount of the supplementary feeding and the quantity and quality of summer pastures should therefore have an increasing effect on the productivity of reindeer stock. In order to outline better the present carrying capacity problems on pastures in the Finnish reindeer management area we focused some of the most important productivity factors of Finnish reindeer stock from 1993 to 1999. The results showed that the productivity of reindeer stock in Finland was dependent especially on two main elements: amount of reindeer feeding and reindeer densities on summer pastures. Winter pastures had no clear effect on productivity when analysing the entire management area. High productivity figures in reindeer stock (calf production, carcass mass and meat production per reindeer) were reached in the management districts where winter feeding was the most abundant, reindeer densities relatively low and summer pastures abundant. An increase in reindeer density on summer pastures raised meat production per total summer pasture area but decreased carcass mass of reindeer calves and meat production per reindeer. It seems that the fundamental factor for keeping the reindeer stock productivity sustainable at a high enough level is to optimize the longterm reindeer densities on pastures. Summer pastures may gradually become a limiting factor for reindeer stock productivity in some areas if overgrazed and decreased winter pastures are only compensated for by winter feeding of reindeer.

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Section: Discussionmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Kumpula¹,

Colpaert

Nieminen³

2002

Ran

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“…The long distance movements of herds from calving to wintering grounds covered a wide biogeographical variation (three biomes) difficult to classify in a reasonable number of vegetation classes. The predominance of terrestrial lichens in the cari¬ bou winter diet (Gauthier et al, 1989;, of graminoids (mostly Cyperaceae) in spring, and of dwarf birch leaves (Betula glandulosa) and other shrubs in summer (Crête & Doucet, 1998) had to be integrated in the definition of vegetation class¬ es because of the the critical importance of the calv¬ ing grounds. Moreover, disturbance by forest fires that affects lichen regeneration, and lichens abun¬ dance which can influence caribou winter distribu¬ tion (Couturier & St-Martin, 1990) add a temporal dimension to mapping.…”

Section: Rangifer Special Issue No 14 2003mentioning

confidence: 99%

Mapping caribou habitat north of the 51st parallel in Québec using Landsat imagery

Chalifoux¹,

Saucier²,

Doucet³

et al. 2003

Ran

Self Cite

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A methodology using Landsat Thematic Mapper (TM) images and vegetation typology, based on lichens as the principal component of caribou winter diet, was developed to map caribou habitat over a large and diversified area of Northern Québec. This approach includes field validation by aerial surveys (helicopter), classification of vegetation types, image enhancement, visual interpretation and computer assisted mapping. Measurements from more than 1500 field sites collected over six field campaigns from 1989 to 1996 represented the data analysed in this study. As the study progressed, 14 vegetation classes were defined and retained for analyses. Vegetation classes denoting important caribou habitat included six classes of upland lichen communities (Lichen, Lichen-Shrub, Shrub-Lichen, Lichen-Graminoid-Shrub, Lichen-Woodland, Lichen-Shrub-Woodland). Two classes (Burnt-over area, Regenerating burnt-over area) are related to forest fire, and as they develop towards lichen communities, will become important for caribou. The last six classes are retained to depict remaining vegetation cover types. A total of 37 Landsat TM scenes were geocoded and enhanced using two methods: the Taylor method and the false colour composite method (bands combination and stretching). Visual inter¬ pretation was chosen as the most efficient and reliable method to map vegetation types related to caribou habitat. The 43 maps produced at the scale of 1:250 000 and the synthesis map (1:2 000 000) provide a regional perspective of caribou habitat over 1200 000 km 2 covering the entire range of the George river herd. The numerical nature of the data allows rapid spatial analysis and map updating.

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Vertebrate Herbivory and Its Ecosystem Consequences

Oksanen

Olofsson

2009

Encyclopedia of Life Sciences

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Herbivory is a process where animals obtain energy and nutrients from vegetative plant parts (leaves, stems, etc.). Herbivory is called grazing, browsing or folivory, depending on the size of the herbivore and the type of plant tissue consumed. The consumption is actually performed by microbes in the digestive system. The role of the animal is to prepare the material and to provide a good environment for the microbes. This requires specializations, making herbivores a distinct animal group. This article focuses on consequences of herbivory by vertebrates. Vertebrate herbivory can change forests to heathlands or grasslands and influence the composition and species richness of the herbaceous vegetation.

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Persistent Suppression in Dwarf Birch after Release from Heavy Summer Browsing by Caribou

Cited by 44 publications

References 26 publications

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

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

Mapping caribou habitat north of the 51st parallel in Québec using Landsat imagery

Vertebrate Herbivory and Its Ecosystem Consequences

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