The problem, said James, DNR's fisheries chief, is that as water levels drop, fish compete for oxygen with each other, aquatic vegetation and algae blooms. On land, deer and other larger species should adapt without much trouble, biologists say, though they expect it won't be as easy for smaller, less-mobile species such as wild turkeys, which depend on insects, lush ground-level forage and farmers' leftover corn silage for food.