Climate change is not the main cause of the northward shift in the range of woodland caribou in Quebec, concludes a study published Tuesday in the journal Global Change Biologyreinforcing the scientific consensus on the role of human activities in the decline of the iconic deer.
From 1850 to 2010, the southern limit of the caribou range would have only declined by about 105 kilometers, instead of 620, if the only factor in question had been the northward movement of favorable climatic conditions. to the species, the authors calculated.
Climate change therefore explains “only about 17% of the observed decline” in the distribution of caribou over 160 years, notes the study carried out by researchers from the University of Quebec at Rimouski (UQAR), from the Canadian Service of Forests, from the University of Quebec in Montreal and the Ministry of the Environment, the Fight against Climate Change, Wildlife and Parks of Quebec.
“It’s quite clear that there would be caribou much further south today, if it was just the climate that guided the distribution of caribou in space,” summarizes the professor of animal ecology at the UQAR, Martin-Hugues St-Laurent, who supervised the study.
The researchers’ work consisted of cross-referencing the historical distribution of caribou with models of past climate, making it possible to follow the geographic evolution of climatic conditions favorable to the species.
“It’s a very innovative study. [sur l’analyse] species-climate relationships,” underlines Mr. St-Laurent.
Setback caused by human activities
The “relatively limited impact of climate” and the extent of the decline in the caribou range in Quebec “strengthen the scientific consensus” indicating that this decline of the caribou is mainly caused by human activities, write the authors of the ‘study.
“The distribution of woodland caribou has probably been shaped by anthropogenic factors that have disrupted the state of equilibrium of the species with its climatic environment since 1850,” they say, citing logging, agriculture and ‘urbanization.
Human exploitation of natural resources has converted most of the mature coniferous forests on which caribou depend for food and evasion from predators into “a matrix of recent cutblocks, mixed stands, and regenerating hardwoods.” and small remnants of residual old stands, all crossed by a dense network of forest roads,” underlines the study.
The study thus debunks the idea “commonly raised by opponents of caribou conservation” that logging and the extraction of natural resources have nothing to do with “the major pan-Canadian decline of the caribou,” indicate the authors.
This argument is notably used by the Alliance Forêt Boréale, a paramunicipal organization in Saguenay–Lac-Saint-Jean and the North Shore.
“While the evidence for range contraction caused by climate is scant, the evidence that it is caused by habitat loss is overwhelming,” the study reads.
Hope for recovery
Due to the influence of this discourse on caribou recovery strategies, it was “crucial” to study the specific impact of climate change on the current distribution of the species, say the authors of the study.
And their conclusions give “a little hope” regarding the recovery of the caribou in Quebec, by proving that it is not useless to work there, affirms Martin-Hugues St-Laurent.
“It shows that the defeatism that says we are going to lose the caribou with climate change is false,” he says.
“We can think that with restoration efforts, we could bring back caribou [au sud de sa répartition actuelle] “, where the climatic conditions are favorable for it, explains the researcher.
We should technically have caribou in Quebec until about the 46the parallel, between Val-d’Or and Charlevoix. The climate would be favorable there.
Martin-Hugues St-Laurent, professor of animal ecology at UQAR
While climate change has had little impact on caribou decline so far, it could have more impact in the future as the climate crisis grows, study warns .
“The combined negative effect of anthropogenic pressures and global warming has been identified as a significant threat to many endangered species,” recalls the document, citing anticipated changes in the composition of forests, the increase in fires, the distribution of parasites, pathogens, predators and competitors.
Climate change only explains 17% of the northward shift in the range of woodland caribou between 1850 and 2010 in Quebec, concludes a new study.
This observation reinforces the scientific consensus according to which human activities are mainly responsible for the decline of the caribou.
The study thus demonstrates the relevance of caribou recovery efforts in Quebec, indicate its authors.
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- 39 km/decade
- Speed at which the southern limit of the woodland caribou range moved northward in Quebec between 1850 and 2010, according to the study
- 6.5 km/decade
- Speed at which the southern limit of the woodland caribou range in Quebec would have moved northward between 1850 and 2010 if climate change were the only factor involved, according to the study