Adobe bricks can help identify historic weed flora – a case study from south-western Hungary

Abstract

Background: The adobe bricks of old buildings can preserve diaspores of cultivated and weed species associated with arable fields. Recovery of these plant remains can provide insight into historical agriculture, and former weed flora.

Aims: This study aims to describe and evaluate the changes in the weed flora in south-western Hungary, based on archaeobotanical findings and contemporary plot surveys.

Methods: Plant remains of 51 adobe bricks dating from 1850 to 1950 were identified in south-western Hungary and compared with the flora of 104 plots from the same region.

Results: A total of 276 species were identified from the adobe bricks, while the present-day plot survey yielded 305 species. A significant difference was found between the historical (60- to 160-year-old) and current species richness of the weed flora. The proportion of rare and threatened species decreased by 38.1%. A total of 142 weed species identified from the adobe bricks have declined, and 40 of them even disappeared in comparison with the contemporary surveys. Today, in Hungary and neighbouring countries, more than 80 of these species are rare or threatened and some of them are extinct or critically endangered.

Conclusions: Our findings show that many weed species that flourished in the early twentieth century have declined. This is most likely due to the intensive management practices of cultivated fields and the spread of invasive neophyte taxa. We showed that analysing the botanical information preserved in adobe bricks is a reliable method that can provide evidence of long-term changes in weed flora.

Keywords:

• desiccated diaspores
• diversity loss
• Nationwide Weed Surveys
• seeds
• Red List
• threatened weeds

Acknowledgements

The authors thank Mónika Czigler for her help in processing the adobe bricks and Sándor Gara for his help in processing the regional data of the 2nd and 3rd NWSs. We also thank Patrick Murphy, Dr Suzanne Hampton, Dr Hamp Hampton and Mark Mariano for the linguistic improvement of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Tamás Henn

Tamás Henn is a Ph.D. student and assistant curator. He is currently working on the examination of desiccated seed assemblages from natural building materials in south-western Hungary.

Dávid U. Nagy

Dávid U. Nagy is a Ph.D. student; he is currently studying on the ecology of the invasive plant species Solidago gigantea in Hungary.

Róbert W. Pál

Róbert W. Pál is an associate professor; he is currently studying the biogeography of invasive plant species.