ABSTRACT
Peatlands are considered as three-dimensional landforms which have both horizontal and vertical gradients. The vertical gradient in peatlands from older to younger, is primarily developed as a result of the accumulation of peat through time. In this chapter, a conceptual model for understanding the physical, hydrological, chemical, and biological processes regulating peat accumulation and system dynamics is presented. The pollen and spore records contained in peatlands in southern Ontario show a major change along the vertical gradient coincident with the time of arrival of the first European settlers. It appears that European settlement has had a major impact on the peatland systems in southern Ontario by causing both gains and losses. A scheme for classifying peatlands affected by human activity is presented. Such knowledge of overall peatland conditions and the magnitude of human impact is vitally important to the management, restoration, and conservation of peatland resources.
