Biological Invasions

, Volume 16, Issue 10, pp 2195–2208

The non-native turf-forming alga Caulacanthus ustulatus displaces space-occupants but increases diversity

  • Jayson R. Smith
  • Sean C. Vogt
  • Faye Creedon
  • Benjamin J. Lucas
  • Douglas J. Eernisse
Original Paper

DOI: 10.1007/s10530-014-0658-5

Cite this article as:
Smith, J.R., Vogt, S.C., Creedon, F. et al. Biol Invasions (2014) 16: 2195. doi:10.1007/s10530-014-0658-5

Abstract

Non-indigenous seaweeds can be found in coastal habitats worldwide yet the ecological effects of only ~6 % of macroalgal introductions have been studied. The turf-forming red alga Caulacanthus ustulatus, a putative introduction from Asia, was discovered in southern California in 1999, yet has received very little attention despite being common in rocky intertidal habitats in the region. The purpose of this study was to evaluate the potential effects of Caulacanthus on native invertebrate and seaweed community composition. Macrofaunal, meiofaunal, and macroalgal community structure and diversity were compared between patches with (non-native) and without Caulacanthus (native) in the upper intertidal zone at 5 locations in southern California. Caulacanthus appears to displace macro invertebrates, such as barnacles, limpets, and periwinkles, while facilitating a more diverse array of meiofauna and macroalgae. This is likely due to the formation of a novel turf habitat in the upper zone where turfs are uncommon in this region naturally; algal turfs can increase habitat complexity, trap sediment, and maintain moisture during low tide which likely benefits meiofauna and seaweeds by providing food, habitat, or refuge from desiccation stress. Subsequent comparisons of invertebrate and seaweed assemblages were conducted in native and non-native patches at one site in the upper intertidal zone as well as in the middle intertidal zone where a native turf zone exists. Despite differences in community composition in the upper intertidal zone, no differences were observed in the middle zone, providing support that the novel turf created by Caulacanthus in the upper zone drives community differences.

Keywords

Non-native seaweedsExotic or introduced speciesRocky intertidal ecologyNon-native species impactsNovel turf forming hypothesis

Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  • Jayson R. Smith
    • 1
  • Sean C. Vogt
    • 2
  • Faye Creedon
    • 2
  • Benjamin J. Lucas
    • 1
  • Douglas J. Eernisse
    • 2
  1. 1.Department of Biological SciencesCalifornia State Polytechnic University, PomonaPomonaUSA
  2. 2.Department of Biological ScienceCalifornia State University, FullertonFullertonUSA