A team of researchers discovered that grazing reindeer reduce the height and abundance of tundra shrubs, which increases the level of surface albedo – a term referring to the amount of solar energy reflected by Earth back into space. Their findings were published Wednesday in the journal Environmental Research Letters.
“The effect reindeer grazing can have on albedo and energy balances is potentially large enough to be regionally important,” said lead author Mariska te Beest. “It also points toward herbivore management being a possible tool to combat future warming.”
The team combined land-surface computer modeling with measurements of albedo and vegetation characteristics taken in Reisadalen, Troms, Norway – an area with four vegetation types that varied in shrub height and volume. A more than 50-year-old fence separated areas with heavy and light grazing by reindeer, serving as a unique experimental setup.
Reindeer activity was estimated through vegetation trampling indicators and feces collection. The researchers also measured the abundance of vegetation, its leaf-area index, soil moisture and temperature levels, as well as albedo levels.
“Our modeling results showed this increase in albedo would result in a corresponding decrease in net radiation and latent and sensible heat fluxes – indicating that heavily grazed sites absorbed less radiation,” te Beest said.
She added, “Although the estimated differences might appear small, they are large enough to have consequences for the regional energy balance.”