An extreme climate gradient-induced ecological regionalization in the Upper Cretaceous Western Interior Basin of North America

The Upper Cretaceous Western Interior Basin of North America provides a unique laboratory for constraining the effects of spatial climate patterns on the macroevolution and spatiotemporal distribution of biological communities across geologic timescales. Previous studies suggested that Western Interior Basin terrestrial ecosystems were divided into distinct southern and northern communities, and that this provincialism was maintained by a putative climate barrier at ∼50°N paleolatitude; however, this climate barrier hypothesis has yet to be tested. We present mean annual temperature (MAT) spatial interpolations for the Western Interior Basin that confirm the presence of a distinct terrestrial climate barrier in the form of a MAT transition zone between 48°N and 58°N paleolatitude during the final 15 m.y. of the Cretaceous. This transition zone was characterized by steep latitudinal temperature gradients and divided the Western Interior Basin into warm southern and cool northern biomes. Similarity analyses of new compilations of fossil pollen and leaf records from the Western Interior Basin suggest that the biogeographical distribution of primary producers in the Western Interior Basin was heavily influenced by the presence of this temperature transition zone, which in turn may have impacted the distribution of the entire trophic system across western North America.

Supplemental Material: An extreme climate gradient-induced ecological regionalization in the Upper Cretaceous Western Interior Basin of North America

Additional methods descriptions, figures, tables, and paleotemperature and paleobotany databases.

Supplemental Material: An extreme climate gradient-induced ecological regionalization in the Upper Cretaceous Western Interior Basin of North America

Additional methods descriptions, figures, tables, and paleotemperature and paleobotany databases.

Phytoclimatic Stages and Vegetation in Baden - Württemberg and Emilia - Romagna

The assessment of ecosystems and landscapes requires reliable and simple tools. Climate determines broad type and distribution of ecosystems. Therefore, it is a major factor to consider in environmental analysis and ecological regionalization. A standardized bioclimatic classification would be useful to characterize and compare different ecosystems. In this paper, Defaut’s Phytoclimatic System (DSPS) was tested at regional scale in two European areas: Baden-Württemberg (Germany) and Emilia-Romagna (Italy). DSPS phytoclimatic units and vegetation belts and climatic parameters are illustrated and discussed. In addition, as an example application, a map of phytoclimatic units of Emilia-Romagna is designed. Some challenges in matching vegetation to DSPS were found: 1) in areas where transition from one stage to another are not sharply delineated and different vegetation types are intermixed; 2) in alluvial lowlands; 3) in heavily anthropized areas. In conclusion, the results of this study suggest that DSPS can be a useful tool in ecological regionalization and in landscape analysis.