The process of secondary succession happens in stages, with each stage playing a crucial role in restoring the land to a stable state.

Pollen can help scientists track changes in vegetation through time, as they respond to moderations of the climate, be that glaciation or deglaciation with transitions into and out of ice ages.

For example, detailed investigations in the Himalayas demonstrate that late-successional species are increasingly outcompeting pioneer species, resulting in a marked upslope movement of the ...