The development of patterned mosaic landscapes: an overview

The articles in this special issue review what is known about the development of wetlands in landscapes and of patterns in various kinds of wetlands around the world with an emphasis on wetlands with treed patches ( tree islands) like the Okavango Delta and the Everglades. Wetlands with treed patches have much in common with their terrestrial counterparts in arid regions. Both are mosaic landscapes in which the patches of trees are distributed in a non-random fashion in a matrix of herbaceous vegetation. In these landscapes, the treed patches are both biogeochemical and biodiversity hotspots. They are biogeochemical hotspots because treed patches preferentially acquire nutrients and other limited resources, like water in arid regions. They are biodiversity hotspots because treed patches are habitats with environmental and structural characteristics very different from those of the herbaceous matrix in which they are found. Consequently, treed patches attract and support populations of many plant and animal species that otherwise would not be found in the area. Studies and simulation models of arid mosaic landscapes have generated a number of hypotheses about the structure and functions of mosaic landscapes, most of which have yet to be tested, especially in wetland mosaic landscapes.