Allelopathic potential of Helleborus dumetorum and its prospects for conservation with gardening

Abstract

To tackle global biodiversity loss, we will need to sustain biodiversity beyond protected areas. Here we present a case study of a rare and threatened native species Helleborus dumetorum. First, we assessed by laboratory experiments if H. dumetorum has a competitive advantage over weeds because of its allelopathic potential; secondly, we reviewed the literature to discuss if this threatened species could be conserved as an ornamental species for gardening while at the same time its cultivation would benefit local biodiversity. Using bioassays, we tested the allelopathic potential of aqueous extracts of H. dumetorum leaves and of soil samples, collected at or away from H. dumetorum plants, on garden cress Lepidium sativum germination and seedling development. The results confirmed the presence of H. dumetorum aqueous allelochemicals in leaves as well as allelopathic effects of the soil where H. dumetorum was growing, supporting the competitive advantage of H. dumetorum. Literature review combined with our observations in the field indicated more characteristics of H. dumetorum suitability for ornamental purposes and species’ conservational opportunities: easy and successful transplanting, survival in various habitats, no invasive potential, flowering in early spring, long-lived leaves. Our study shows, that considering threatened native plants for ornamentals could have a multitude of benefits for local biodiversity.