Diversity patterns of Arctic herbivores are only partly determined by temperature; interactions with plants and predators are more important. The diversity of herbivores varies across the Arctic, and until now, no one knew whether this was shaped by physical environmental factors, like temperature, or biotic factors, such as plant productivity.

Understanding the forces that shape biodiversity is essential
for improving our ability to predict the responses of ecosystems to rapid, ongoing
environmental change. In the Arctic, herbivores often play a key role in the
functioning of terrestrial ecosystems. Vertebrate herbivores are particularly
important as they affect the structure and dynamics of plant communities and provide
food for higher trophic-level predators. The results of this study showed that
herbivore diversity in the Arctic is higher in areas with greater plant productivity
and with higher diversity of predators.

– We cannot only
consider temperature and precipitation when projecting how Fennoscandian tundra
ecosystems might change in the coming decades. We need to account for the fact that,
for example, large reindeer herds can be beneficial by potentially limiting
encroachment of shrubs and mountain birch forest into the fjells. Forested fjells
instead can facilitate rapid climate warming, says Research Professor Bruce Forbes
from the Arctic Centre at the University of Lapland, who is the member of the
research initiative.

The study is the result of a new
collaborative research initiative, the Herbivory Network, involving researchers from
10 different countries. The research team collected information on the distribution
of all 73 species of vertebrate herbivores that occur in the Arctic, including
migratory geese, reindeer and caribou, lemmings and free-ranging domestic sheep.

More information:

Herbivory Network: http://herbivory.biology.ualberta.ca

The study “Biotic interactions mediate patterns of herbivore
diversity in the Arctic” is published in the journal Global Ecology and Biogeography

Bruce Forbes
Research Professor, Docent

Arctic Centre, University of Lapland
+358 40 847 9202,
bruce.forbes (at) ulapland.fi

LaY/AK/JW