Functional vulnerability of ecosystems across Canada

What is functional diversity?

Functional diversity directly relates species to ecosystem functioning and services using species' functional traits, thereby capturing the different roles species can play in their communities. Understanding how functional diversity varies across space and how vulnerable this element of diversity is to species loss, can help inform conservation and can enable predictions for the future. In this project, I aimed to both quantify how functional diversity varies across Canada, and test the functional vulnerability of Canadian ecosystems to species loss.

Results

  • High arctic ecosystems have uncharacteristically high vertebrate functional diversity, driven by disparate latitudinal patterns in body size between birds and mammals (Fig. 1)

  • High arctic communities are also the most vulnerable to species loss. The extinction of species at risk or megafauna could reduce functional diversity by 20-60%, likely causing the collapse of vertebrate food webs in these ecosystems (Fig. 2)

  • Functional vulnerability is mainly driven by a reduction in functional redundancy, which tends to be higher in southern, species-rich ecosystems, and lower in northern, species-poor ecosystems (Fig. 3)

Figure 1 — Maps of functional richness for different taxonomic groups across Canada

Figure 2 — Changes in functional richness driven by species loss for Canadian Ecoregions (top) and Ecozones (bottom)

Figure 3 — Patterns of functional redundancy across Canadian Ecoregions (top) and Ecozones (bottom) along with average species contributions to functional diversity (right)

Conclusions

Arctic ecosystems in Canada comprise the most functional rich and vulnerable ecological communities. As rates of species loss increase due to climate change and habitat loss, the future of these ecosystems is increasingly uncertain. The threat of ecological collapse can be mitigate to some degree by focused and targeted conservation, which is likely necessary to preserve the future of these ecosystems.