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Caribou Recruitment Was Lower in More Productive, Disturbed Canadian Landscapes

Woodland caribou calf in Alberta, Canada
Research · Ecology

Calf recruitment in boreal woodland caribou (Rangifer tarandus) was lower in more productive and more heavily disturbed landscapes with richer predator and alternative-prey communities, according to a Canada-wide study published in March 2026. Researchers combined demographic data from 40 caribou study areas with net primary productivity, disturbance footprints, moose density and predator and prey richness. Net primary productivity describes how much new plant biomass a landscape produces and therefore how much energy is initially available to the food web.

Recruitment, measured as the number of calves surviving to about ten months of age relative to adult females, declined along gradients of higher net primary productivity, anthropogenic disturbance and greater predator and alternative-prey richness. Structural modelling indicated a pathway in which higher productivity was associated with more disturbance, which in turn was associated with richer prey and predator communities and lower caribou recruitment.

Apparent competition may help explain lower calf recruitment

This pattern is an example of apparent competition, an indirect food-web interaction in which abundant alternative prey can support more generalist predators and thereby increase predation pressure on another prey species such as caribou. When human disturbance helps create those conditions, the authors refer to the process as disturbance-mediated apparent competition.

Adult female survival followed a different pathway

Adult female survival showed a different pathway. Higher primary productivity was associated with higher moose density, which in turn was linked to lower caribou survival. In this part of the analysis, disturbance was not the intermediate step. Taken together, the results indicate that the full disturbance–prey–predator pathway was strongest in more productive parts of the boreal landscape, while productivity was also linked to adult survival through moose density.

The authors argue that productivity helps determine where human disturbance, alternative prey and predators become concentrated, changing the ecological context in which caribou populations persist across Canada.

Sources and image credit

  1. Neufeld, B. T., Superbie, C., Johnson, C. A., Fortin, D., & McLoughlin, P. D. (2026). Disturbance-mediated apparent competition across boreal landscapes: the role of primary productivity. Landscape Ecology, 41, 88. https://doi.org/10.1007/s10980-026-02336-9Primary research article published online 30 March 2026. The study combined calf recruitment data from 40 boreal caribou study areas across Canada and adult female survival data with net primary productivity, anthropogenic and fire disturbance, moose density, and predator and alternative-prey richness. Recruitment declined with higher productivity, anthropogenic disturbance and richer predator–prey assemblages. Higher productivity was associated with higher moose density and lower adult female survival.

Image: Ontley / Wikimedia Commons — woodland caribou calf from the Little Smoky herd in Alberta, Canada, 5 January 2004. Representative image for this story; not presented as an animal or scene from the reported study or event. · CC BY-SA 4.0 · Source

About this content: This story was produced with AI assistance within an editorial workflow developed by Wildlife Vagabond. Editorial responsibility remains with Wildlife Vagabond.How AI is used

Ecology

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Reindeer Rangifer tarandus Explore species Moose Alces alces Explore species

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