caa a22 4500 378931814 CHVBK 20180305123631.0 cr unu---uuuuu 161128e20040701xx s 000 0 eng 10.1515/BOT.2004.031 doi (NATIONALLICENCE)gruyter-10.1515/BOT.2004.031 Crusts of the alien bryozoan Membranipora membranacea can negatively impact spore output from native kelps (Laminaria longicruris) [Elektronische Daten] [Bettina Saier, Annelise S. Chapman] Severe outbreaks of the crust-forming European bryozoan Membranipora membranacea in northwestern Atlantic waters have caused extensive losses of kelp canopy through a process of defoliation. Here, we report how these crusts may negatively impact kelp beds by reducing spore release from fertile blades. In the laboratory, fully and partially encrusted sori of Laminaria longicruris released significantly fewer spores than bryozoan-free blades. Through field observations, we quantified the potential ecological impact of the encrusting mechanism. Unlike previous years, infestation was minimal in 2002 when only 4% of kelp surface areas were covered with bryozoan colonies (with a maximum of 72% of kelp individuals infested). This indicates strong interannual variability in the scale of impact on kelp spore release. In years when Membranipora encrustation impact is high and coincides with invasion by other nonnative species and/or elevated levels of sea urchin grazing, there is the potential for conversion of the rocky subtidal benthos to a new, possibly stable community state. © Walter de Gruyter Hydrobiology nationallicence Mycology, fungi nationallicence Botany & plant sciences nationallicence alien invasive species nationallicence Membranipora membranacea nationallicence Laminaria longicruris nationallicence spore release nationallicence Saier Bettina Biologische Anstalt Helgoland, Alfred Wegener Institute, Foundation for Polar and Marine Research, P.O. Box 180, 27483 Helgoland, Germany aut Chapman Annelise S. Dalhousie University, Biology Department, Halifax, Nova Scotia B3H 4J1, Canada aut Botanica Marina Walter de Gruyter 47/4(2004-07-01), 265-271 0006-8055 47:4<265 2004 47 botm https://doi.org/10.1515/BOT.2004.031 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/BOT.2004.031 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Saier Bettina Biologische Anstalt Helgoland, Alfred Wegener Institute, Foundation for Polar and Marine Research, P.O. Box 180, 27483 Helgoland, Germany aut NATIONALLICENCE 700 1- Chapman Annelise S. Dalhousie University, Biology Department, Halifax, Nova Scotia B3H 4J1, Canada aut NATIONALLICENCE 773 0- Botanica Marina Walter de Gruyter 47/4(2004-07-01), 265-271 0006-8055 47:4<265 2004 47 botm CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter