IncreasedCannabis/Humuluspollen, an indicator of European agriculture in Iowa

Abstract

The percentages of Ambrosia-type pollen increase in the upper few centimeters of many North American cores of lake sediments or bog peats, For much of eastern North America south of 50 °N, this increase is easily recognizable in pollen diagrams and indicates the time when persons of European origin settled in an area. The actual biostratigraphic proof that this "Ambrosia rise" occurs with settlement requires correlating the Ambrosia rise with the first appearance or the rise in abundance of pollen types from both cultivated and non-native plants. This requirement is particularly important in the Midwest where Ambrosia is a native weed. Our results illustrate the potential of Cannabis/Humulus pollen as an indicator of settlement and cultivation in Iowa.

Diatom floristic change and lake paleoproduction as evidence of recent eutrophication in shallow lakes of the midwestern USA

“…Of the 22 cores with identifiable settlement markers, 21 dated to between 1837 and 1880 (mean = 1856, Table 3, Fig. 1), which is a reasonable approximation for the timing of Euro-American settlement in this region according to US Census data (Van Zant et al 1979). Uncertainty (±1 SD) associated with settlement dates for the individual cores ranged from 6 to 36 years (mean = 18 years, Fig.…”

“…Lakes in this study are located in the midwestern United States where tall-grass prairie was converted for agricultural land use in the mid-1800s (Van Zant et al 1979). Water bodies in the calibration set include both natural lakes and impoundments, but reconstructions were limited to natural lakes, all of which were formed by the retreat of glaciers in the early Holocene (ca.…”

The appearance and disappearance of major vegetational assemblages: Long-term vegetational dynamics in eastern North America

“…The final map in the series is for 500 yr B.P., which is just before European settlement in North America, and thus illustrates the 'pre-settlement' vegetation patterns before widespread logging and agriculture modified the pollen record in much of eastern North America south of 50°N Van Zant et aL, 1979;Gaudreau & Webb, 1985). The final map in the series is for 500 yr B.P., which is just before European settlement in North America, and thus illustrates the 'pre-settlement' vegetation patterns before widespread logging and agriculture modified the pollen record in much of eastern North America south of 50°N Van Zant et aL, 1979;Gaudreau & Webb, 1985).…”

Pollen indicators of human activity

“…Zea mays) occurred together with cropland weed pollen, such as Portulaca, Rumex, Plantago, Urtica, indicating agricultural practice of the time [14,32] . The appearance of Cannabis/Humulus in central western part of North America was related to the plantation of Cannabis during the twentieth century in this region as documented in literature [62,63] . In the eastern part of North America, the wide occurrence of ragweed pollen whose percentage reached 20% 50% marked the arrival of the Europeans and the subsequent wasteland management, and was even used as stratigraphic marker [64,65] .…”