DISTRIBUTION

Water mite species of the Mixedwood Plains exhibit six main distribution patterns.

Southeastern. Many species have extensive distributions in the eastern United States between the Atlantic Coast and the Ozark Plateau and reach their northern limit in the Mixedwood Plains and Atlantic-Maritime Ecozones, or contiguous southern regions of the Boreal Shield Ecozone. Populations of these species apparently inhabited Pleistocene refugia with temperate conditions in deciduous forest biomes of southeastern North America well south of the maximum extent of the Laurentide Ice Sheet during the Wisconsinan.

Northeastern. Many species have extensive distributions in the Atlantic-Maritime Ecozone and eastern regions of the Boreal Shield Ecozone and reach their western limit in the Mixedwood Plains Ecozone. These species probably inhabited Pleistocene refugia with temperate conditions in mixed forest biomes along the Atlantic Coast south of the maximum extent of the Laurentide Ice Sheet.

Boreal. Many species have extensive distributions throughout the Boreal Shield Ecozone and into the Boreal Plain and Cordilleran Ecozones, and reach their southern limit in eastern North America in the Mixedwood Plains and Atlantic-Maritime Ecozones. These species apparently inhabited periglacial Pleistocene refugia with boreal conditions in coniferous forest biomes just south of the maximum extent of the Laurentide Ice Sheet.

Great Lakes Basin. Some species have distributions essentially restricted to the Mixedwood Plains and contiguous mixed forest biomes in the watersheds draining into the Great Lakes. These species may have inhabited Pleistocene refugia with cool temperate conditions in the transition zones between deciduous to coniferous forest biomes during the Wisconsinan Glacial Maximum.

Western. Some species have extensive distributions in the Prairie Ecozone and contiguous grassland biomes of the United States, and reach their eastern limit in the Mixedwood Plains Ecozone, often as disjunct populations. These species apparently inhabited Pleistocene refugia with temperate conditions in grassland biomes in midcontinental regions of North America during the Wisconsinan Glacial Maximum. They may have first colonized the Mixedwood Plains during the Hypsithermal Interval.

Widespread. Some species have distributions that essentially cover all of temperate North America. Populations of these species apparently inhabited Pleistocene refugia with temperate conditions in various biomes south of the ice front across North America.

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