Phenological sequences reveal aggregate life history response to climatic warming.

Climatic warming is associated with organisms breeding earlier in the season than is typical for their species. In some species, however, response to warming is more complex than a simple advance in the timing of all life history events preceding reproduction. Disparities in the extent to which different components of the reproductive phenology of organisms vary with climatic warming indicate that not all life history events are equally responsive to environmental variation.

Relationships between graminoid growth form and levels of grazing by caribou (Rangifer tarandus) in Alaska.

Herbivores and their forage interact in many ways, in some instances to the benefit or detriment of herbivore and vegetation. Studies of wildebeest (Connochaetes taurinus) in Africa and snow geese (Chen caerulescens) in the Arctic have suggested that these grazers enhance graminoid production in certain sites by repeatedly using them. Other studies have concluded that herbivores are sensitive to local variation in forage quality and quantity, and preferentially use those sites that are intrinsically more productive.