Advances in Ecological Research

adrenal adult aggressive analysis animals aphids arthropods behavior biological birth rate breeding season brown lemming changes chicks Chitty Clethrionomys Coleoptera concept cultural cultural ecology Daphnia decline phase declining populations defined density function Diptera dispersal diversity ecological approach ecological psychology ecologists economics ecosystem environment environmental equation example factors females Gaines and Krebs genetic geography grey partridge growth habitat human ecology hypothesis important increase phase individuals integration interaction June larvae lemming populations Lemmus levels litter low numbers males mass microtine populations Microtus agrestis Microtus californicus Microtus pennsylvanicus mortality natural neonates nutrient ochrogaster organization parasites peak populations Pitelka population cycle population decline population density population fluctuations predators prey problem relationship reproduction rodents rutilus samples social sociology spatial species spring barley structure study area submodels summer survival rates tion trapping Univ variables voles and lemmings West Sussex wheat York