BioOne Online Journals - Linking Top-Down Forces to the Pleistocene Megafaunal Extinctions

BioOne Online Journals - Linking Top-Down Forces to the Pleistocene Megafaunal Extinctions: "Humans, in conjunction with natural top-down processes and through a sequence of cascading trophic interactions, may have contributed to the Pleistocene megafaunal extinctions. The arrival of the first humans, as hunters and scavengers, through top-down forcing, could have triggered a population collapse of large herbivores and their predators."

ESA Online Journals - Interacting regime shifts in ecosystems: implication for early warnings

ESA Online Journals - Interacting regime shifts in ecosystems: implication for early warnings: "Big ecological changes often involve regime shifts in which a critical threshold is crossed. Thresholds are often difficult to measure, and transgressions of thresholds come as surprises. If a critical threshold is approached gradually, however, there are early warnings of the impending regime shift. For example, in a one-dimensional ecosystem dynamics, autocorrelation approaches 1 from below, variance and skewness increase, and variance spectra shift to lower frequencies"