Presented by: Robert Serrouya

This webinar has two components:

  1. Launched in June 2018, the National Boreal Caribou Knowledge Consortium (NBCKC) is a forum for collaborative knowledge generation and sharing to support conservation and recovery of boreal caribou. Within the NCBCK, a population management working group was formed (PMWG), as a result of an action identified in the Federal Action Plan for Boreal Caribou. Population management includes actions intended to provide a relatively immediate benefit to caribou numbers, until the legacy of habitat distance diminishes as a result of habitat restoration and protection. The purpose of the PMWG is to discuss the breadth and efficacy of population management actions under various scenarios, and to rapidly disseminate information across jurisdictions.
  2. Changes in primary productivity have the potential to substantially alter food webs, with positive outcomes for some species and negative outcomes for others. Understanding the environmental context and species traits that give rise to these divergent outcomes is a major challenge to the generality of both theoretical and applied ecology. In aquatic systems, nutrient-mediated eutrophication has led to major declines in species diversity, motivating us to seek terrestrial analogues using a large-mammal system across 598 000 km2 of the Canadian boreal forest. These forests are undergoing some of the most rapid rates of land-use change on Earth and are home to declining caribou (Rangifer tarandus caribou) populations. Using satellite-derived estimates of primary productivity, coupled with estimates of moose (Alces alces) and wolf (Canis lupus) abundance, we used path analyses to discriminate among hypotheses explaining how habitat alteration can affect caribou population growth. Hypotheses included food limitation, resource dominance by moose over caribou, and apparent competition with predators shared between moose and caribou. Results support apparent competition and yield estimates of wolf densities (1.8 individuals 1000 km−2) above which caribou populations decline. Our multi-trophic analysis provides insight into the cascading effects of habitat alteration from forest cutting that destabilize terrestrial predator–prey dynamics. Finally, the path analysis highlights why conservation actions directed at the proximate cause of caribou decline have been more successful in the near term than those directed further along the trophic chain.