Heracleum sosnowskyi or Heracleum mantegazzianum? DNA-based identification of invasive hogweeds (Apiaceae) in two key regions of the species' invasion history in the territory of the former Soviet Union

Abstract

Abstract Heracleum mantegazzianum Sommier & Levier and Heracleum sosnowskyi Manden. are two species that belong to the giant invasive hogweed complex. H. mantegazzianum is predominantly found in Western European countries, while H. sosnowskyi is invasive in the European part of Russia and Eastern European countries. The taxonomy of the Heracleum genus is quite complex, and identifying these species requires extensive expertise. Surprisingly, although H. mantegazzianum and H. sosnowskyi are considered separate species, their morphological and ecological-physiological properties, as well as their ontogeny and population structure, exhibit remarkable similarities, making them ecological twins. The intentional introduction of this invasive species was initially conducted in the cities of Kirovsk city (Murmansk region, Russia) and Syktyvkar city (Komi Republic, Russia). Plant materials sourced from these two regions were subsequently distributed to all regions encompassing the modern hogweed invasion range across the former USSR countries. The objective of this study was to test the hypothesis that the plants initially introduced in Kirovsk and Syktyvkar actually belong to H. mantegazzianum. To accomplish this, herbarium material was collected, and DNA barcoding was performed on 16 samples of giant invasive hogweed from the vicinity of the cities of Kirovsk and Syktyvkar, as well as on 30 H. mantegazzianum samples collected within its native range in the Western Caucasus. The results of morphological identification combined with DNA barcoding demonstrate that H. mantegazzianum and the plants growing in Kirovsk and Syktyvkar belong to the same species – H. mantegazzianum, rather than H. sosnowskyi as previously believed.