TORONTO, Oct. 4 (UPI) -- Populations of herbivores, important in the human food supply chain, could go down as global temperatures go up, Canadian researchers say.
Ecologists at the University of Toronto say differences in the general responses of plants and herbivores to temperature change produces predictable declines in herbivore populations because herbivores grow more quickly at high temperatures than plants do, and as a result the herbivores run out of food.
Studying the phenomenon in a marine environment suggests global warming will cause large shifts in food chains with consequences for global food security and species conservation, one researcher said in a university release Tuesday.
"If warmer temperatures decrease zooplankton in the ocean, as predicted by our study, this will ultimately lead to less food for fish and less seafood for humans," study co-author Benjamin Gilbert of the university's ecology and evolutionary biology department said.
A number of studies have shown how the metabolic rates of plants or animals change with temperature, and Gilbert and his colleagues incorporated these rates into commonly used mathematical models of plants and herbivores to predict how the abundance of each should change with warming.
They confirmed their predictions in an experimental study in which phytoplankton and zooplankton populations in tanks of water shifted significantly with changes in water temperature.
Long-term studies are required, Gilbert cautioned, but he said if their predictions are right, global warming would cause large shifts in food chains.
