Water-filled leaf axils in teasel plants: A study of often overlooked aquatic habitats

Abstract

Teasels (Dipsacus spp.) are among the few European plant species that can create small aquatic ecosystems, known as phytotelmata, in their leaf axils. However, these unique environments have received little research attention. We performed the first detailed study of phytotelmata in teasels, aiming to describe the physical habitat and macroinvertebrate communities across different leaf axil levels. We explored 64 phytotelmata on 20 teasel plants in Slovakia (Central Europe). These small aquatic ecosystems contained less than 100 ml of water, exhibited a pH ranging from slightly acidic to neutral, had very low oxygen content, and showed highly variable conductivity. We collected more than 1000 larvae of Diptera, representing at least ten aquatic invertebrate taxa. The dominant species found in these communities were the chironomid Metriocnemus eurynotus (Holmgren, 1883), followed by ceratopogonids of the genus Dasyhelea. The oldest, bottom-situated phytotelmata showed the highest invertebrate density and species richness, suggesting an important role of ecosystem age and the probability of colonization in the community assembly process. These highly replicated ecosystems with simple communities may serve as useful models for studying various ecological phenomena such as metacommunity dynamics, succession, community assembly, biodiversity-ecosystem functioning or mutualistic interactions.