The Early Permian floras of Prince Edward Island, Canada: differentiating global from local effects of climate change
Ziegler, A.M., Rees, P.M. & Naugolnykh, S. (2002).
Canadian Journal of Earth Sciences, 39: 223-238.

ABSTRACT. New Permian plant specimens are described from Prince Edward Island, Canada. They include attached specimens of leaf and stem genera Walchia and Tylodendron, enabling reconstruction of this Early Permian conifer. Although poorly preserved, the study of these floras extends our knowledge of diversity and climate conditions in the region.

By placing these findings in a broader stratigraphic and geographic framework, we can document the phytogeographic and climate trends through the Carboniferous and Permian in the Maritimes Basin. Combined data on temporal trends in climate-sensitive sediments, as well as macrofloral and microfloral diversities, generally match the independently derived paleolatitudinal estimates. These show the region migrating from the southern subtropics across the equator and into the northern subtropics between the Early Carboniferous and Early Permian.

Evaporites and pedogenic carbonates, together with low diversity floras, match its subtropical position in the Early Carboniferous. In contrast, coals are present in the Late Carboniferous, accompanied by high diversity macro- and microfloral remains, when the region was on or near the equator. However, the subsequent transition to pedogenic carbonates, eolian sands and lower diversity floras is not matched by significant poleward latitudinal motion.

We ascribe these changes to a decrease in moisture availability, as transgressions of epeiric seas became less frequent and finally stopped altogether, causing an increase of continentality in Euramerica.