Abstract:
Bryophytes are widespread in terrestrial ecosystems but little is known about their infl uence on vascular species. Watersoluble leachates (0%, 1%, 5%, 10% concentration) derived from 18 species of bryophytes (mosses 11 species; liverworts 7 species) were tested on the germination and seedling growth of Lactuca sativa and two common trees Melicytus ramifl orus (Violaceae) and Fuchsia excorticata (Onagraceae) in southern New Zealand forests. Bryophyte water soluble extracts (BWSE) have minor impact on seed germination of Lactuca, stimulatory eff ects on radical growth at low (1%) concentrations and inhibitory eff ects at higher concentrations (5 – 10%). For Melicytus the BWSE had variable eff ects, with evidence of strong stimulatory (Dendrohypopterygium fi liculiforme) and inhibitory (Lepidozia concinna) eff ects on germination, but generally inhibited radical growth. BWSE at all test concentrations consistently inhibit both germination and seedling radicle growth in Fuchsia. h e toxicity eff ect of water-soluble leachates varies signifi cantly between bryophyte species but not consistently between mosses and liverworts. Bryophyte species exhibiting strongest inhibition eff ects under control conditions were associated with signifi cantly reduced densities of broadleaved tree seedlings in forest ecosystems. Our results demonstrate that some bryophyte species via allelopathic interactions can inhibit seedling establishment and growth of forest trees. h is mechanism provides an additional factor constraining the spatial distribution of the regeneration niche in forest communities.