title: Divergent ecological strategies determine different impacts on community production by two successful non-native seaweeds.
abstract: The consequences of plant introductions into ecosystems are frequently reported from terrestrial environments, but little is known about the effects on ecosystem functioning caused by non-native primary producers in marine systems. In this study we explored the effects of the invasion by the two filamentous red algae Heterosiphonia japonica and Bonnemaisonia hamifera on the primary production of seaweed communities by using single and mixed cultures of non-native and native red algae. The experiments were conducted both in the presence and absence of herbivores. Biomass production of the invaded community increased more than four times in mixed cultures with H. japonica, while introduction by B. hamifera had no significant effect. The different impact on community production could be explained by differences in life history strategies between the invaders; H. japonica grew considerably faster than the native seaweeds which directly increased the community production, while B. hamifera showed a relatively slow growth rate and therefore had no effect. From previous studies it is known that B. hamifera produces a highly deterrent, but also costly, chemical defence. The assessment of survival and growth of a native generalist herbivore further corroborated that the biomass produced by B. hamifera constitutes a very low-quality food, whereas the performance of herbivores on a diet of H. japonica was comparable to that on native algal diets. In summary, this study demonstrates that successful invaders belonging to the same functional group (filamentous red algae) may have distinctly different impacts on productivity in the recipient community, depending on their specific life history traits.
authors.affiliation: Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91, Stockholm, Sweden, josefin.sagerman@su.se.
authors.forename: Josefin
authors.initials: J
authors.lastname: Sagerman
authors.forename: Swantje
authors.initials: S
authors.lastname: Enge
authors.forename: Henrik
authors.initials: H
authors.lastname: Pavia
authors.forename: Sofia A
authors.initials: SA
authors.lastname: Wikström
mesh_terms: D000818:Animals; D018533:Biomass; D060434:Herbivory; D058865:Introduced Species; D000461:Rhodophyta / Q000145:classification / Q000502:physiology*; D012624:Seaweed / Q000145:classification / Q000502:physiology*; D013045:Species Specificity
references.citation: Ecology. 2012 Dec;93(12):2736-45
references.pmid: 23431603
references.citation: Oecologia. 2010 Nov;164(3):833-40
references.pmid: 20821025
references.citation: Biol Bull. 2007 Dec;213(3):226-51
references.pmid: 18083964
references.citation: Ecol Lett. 2009 May;12(5):432-42
references.pmid: 19379137
references.citation: Proc Biol Sci. 2003 Apr 22;270(1517):775-81
references.pmid: 12737654
references.citation: Ecol Lett. 2013 Apr;16(4):487-92
references.pmid: 23331740
references.citation: New Phytol. 2008;177(3):706-714
references.pmid: 18042198
references.citation: Am Nat. 2002 Apr;159(4):396-419
references.pmid: 18707424
references.citation: Biol Lett. 2005 Dec 22;1(4):435-8
references.pmid: 17148226
references.citation: Ecol Lett. 2010 Feb;13(2):235-45
references.pmid: 20002494
references.citation: Ecol Lett. 2011 Jul;14(7):702-8
references.pmid: 21592274
references.citation: Curr Opin Plant Biol. 2000 Aug;3(4):305-8
references.pmid: 10873846
references.citation: Ecol Lett. 2005 Nov;8(11):1165-74
references.pmid: 21352440
references.citation: Ecol Lett. 2012 Aug;15(8):912-22
references.pmid: 22639820
references.citation: Nature. 2006 Oct 26;443(7114):989-92
references.pmid: 17066035
references.citation: Ecol Lett. 2009 Feb;12(2):107-17
references.pmid: 19143824
references.citation: Biom J. 2008 Jun;50(3):346-63
references.pmid: 18481363
references.citation: PLoS One. 2010 Mar 29;5(3):e9788
references.pmid: 20360960
references.citation: Oecologia. 2006 Jul;148(4):593-601
references.pmid: 16532333
references.citation: Nature. 2004 Apr 22;428(6985):821-7
references.pmid: 15103368
references.citation: Oecologia. 2006 Nov;150(2):300-9
references.pmid: 16927104