Abstract

In forested ecosystems dominated by long lived plant species, many ecological processes occur over a time span that is greater than can be studied through conventional experiments. In this seminar I describe three pieces of work that employ ‘natural’ or ‘unintended’ experiments to investigate aboveground and belowground processes and linkages in the long term perspective. The first involves the aboveground and belowground effects of invasive mammals such as deer and rats in New Zealand rainforests that have occurred over a time-span of decades to centuries. The second involves an ongoing study of lake islands in northern Sweden in which historical fire regime drives aboveground-belowground feedbacks in the order of millennia. The third involves the aboveground and belowground consequences of ecosystem retrogression in contrasting long term chronosequences around the world, over the order of millennia and beyond. The consistent theme that emerges from these examples is that feedbacks between aboveground and belowground organisms, and the key traits of the dominant taxa in these groups, serve as major drivers of forest community and ecosystem processes at long-term timescales that are relevant to the dynamics of the forest.