Evidence for rare crop weeds of the Caucalidion group in Southwestern Germany since the Bronze Age: palaeoecological implications

Abstract

The crop weed communities of dry calcareous soils are today very rare and endangered. In the first half of the 20th century this group was already in an advanced stage of disappearance, caused by the intensification of agriculture since the 19th century. Therefore, botanists only found these plants in a few regions with calcareous soils, obviously reflecting the geological conditions. But many archaeobotanical finds are in places where this species was never observed as a living plant and edaphic conditions seem to exclude it. In the western Lake Constance region floristic observations are lacking. Of Orlaya grandiflora, there is now proof from several pollen diagrams that this species did occur regularly and with high frequency in this region from the Late Bronze Age to the 19th century ad. Several other species of the Caucalidion are also reflected in the pollen record, but are less frequent, reflecting the ecological conditions triggered by agriculture; due to soil erosion, topsoils were thin, especially on slopes, with low water capacity, and low yields. The weeds with spiny fruits were distributed over long distances by migrating domestic animals. Pollen grains in high-resolution pollen profiles from the northern Black Forest and Allgäu, where these plants were not to be expected and were never observed, indicate a ubiquitous distribution of the Caucalidion between Late Bronze Age and early Modern Ages in Central Europe and adjacent regions, reflecting the tenuous situation of long-term extensive ard agriculture in hilly landscapes. More and better pollen diagrams and macrofossil studies would bring better evidence.

Life on a hilltop: vegetation history, plant husbandry and pastoralism at the dawn of Bergamo-Bergomum (northern Italy, 15th to 7th century bc)

“…More rarely, pollen occurs in the Domus dei Bragagnoli trench C sequence. As remarked by Perego et al ( 2011 ) and Rösch ( 2018 ), persistently high pollen values of this plant suggest overgrazed dry fields and intensive, free range growing livestock husbandry in open woodlands, which is likely the case for the Bergamo Hill in the Final Bronze Age. On the other hand, sporadic grains may reflect occurrences in secondary but low-human pressure xerophilous grasslands and forest fringes, as observed today in the sub-mediterranean low mountain belt in the Garda region (Figs.…”

“…Low dispersibility pollen discharged by animals, by humans (hay and cereal stubbles: Greig 1984 ) and/or transported by runoff processes before incorporation in sediments may be strongly overrepresented in the context of a watering pond with an accumulation of laminated mud (Kühn et al 2013 ). This feature may explain the abundance of usually low-represented large pollen grains ( Anthericum, occurring in 18 out of 58 samples), often echinate ( Dipsacus in 29 samples, mean value 0.4% + and other Dipsacaceae, Centaurea nigra -type in 51 samples, mean value 3.8%), as well as of very large rare pollen types ( Asphodelus ) and of other pollen types foraged on dry grasslands ( Orlaya grandiflora- type , Helianthemum , see Perego et al 2011 ; Rösch 2018 ) detected in these samples.…”

Does site elevation determine the start and intensity of human impact? Pollen evidence from southern Germany

“…In general, human impact before the medieval period was never strong enough to change the woodland cover completely by interrupting the dominance of Fagus at Großer Ursee, as was the case in the Bodensee region (Rösch 2018). The importance of the conifers Abies and Picea in woodland composition was greater in the Allgäu than in the lowlands.…”