From publisher blurb:
Geography is a series of segues connecting competing biomes to one another. On dry land, forests slowly transition to grasslands and then ultimately to deserts. The boundaries between each ecological system change over time as weather patterns shift, and the creatures dwelling in these habitats alter the environment to suit their specific needs. The same principle applies to the interplay between land and water. Without outside intervention, oceans, rivers, lakes, and streams are not surrounded by impenetrable stone walls or earthen dams distinctly separating aquatic and terrestrial neighbors.
By definition, wetlands are a natural community that is seasonally or permanently saturated by water. In this sense, natural is used to indicate that water normally overruns the landmass on a frequent and recurring basis rather than being caused by an extreme or infrequent event. Thus, a landmass alongside a riverbank that becomes submerged on an annual basis during the monsoon season fits the classification of a natural community, whereas a coastal region or a low-lying area that is flooded once every decade by a passing hurricane would not. To further distinguish wetlands from landmasses susceptible to sporadic flooding, wetlands must also display at least one of the following characteristics: They must support aquatic plant life for at least some portion of the year; their soil is predominately saturated with water, thus creating an anaerobic environment; or the sediment present at or near the surface is saturated with water or covered by shallow water during at least part of the growing season.