Battle of the barnacle newcomers: niche compression in invading species in Kaneohe Bay, Oahu, Hawaii

Abstract

Multiple invasions by ecologically similar species can be viewed as 'natural' addition experiments in which access to key resources might be reduced. Possible outcomes might include:(1) the extirpation of a species already present in the ecosystem, (2) the exclusion of a new invader, or (3) niche compression, with each species using less of the shared resource. Chthamalus proteus, a barnacle that arrived in the Hawaiian Islands ~30 yr ago, is now the most abundant and widespread non-native barnacle in the intertidal zone on the island of Oahu. In a series of field experiments, I demonstrate that the abundance of an earlier invader -the larger, faster growing barnacle Balanus reticulatus -is reduced via substrate pre-emption in the zone of overlap between the 2 barnacle species. A third barnacle, Balanus amphitrite, which invaded Hawaii earlier than the other two, is now virtually absent from locations where it was once abundant and where C. proteus is now the numerical dominant. B. amphitrite did not settle on plates from which C. proteus was removed, suggesting that the presence of C. proteus is not the proximal cause of its decline. B. amphitrite is still present on Oahu, particularly in lower salinity settings. While successively invading barnacles have reportedly replaced each other in other locations around the world, it appears that invasive barnacles on Oahu are undergoing niche compression rather than complete replacement. KEY WORDS: Competition · Barnacle recruitment · Chthamalus proteus · Biological invasions · Balanus Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 381: [175][176][177][178][179][180][181][182] 2009 for space between barnacle species can occur after settlement through overgrowth, undercutting and crushing (Connell 1961b, Wethey 1984. In such interactions, larger, faster growing balanoid barnacles are likely to win over the typically smaller chthamaloid barnacles (Connell 1961b, Stanley & Newman 1980, Wethey 1984. Chthamaloid barnacles as a group tend to have a higher tolerance to air exposure, and where competition with balanoids is strong, may be relegated to the upper intertidal zone, where balanoids either do not settle or do not survive as well.Competition between barnacles can also occur via pre-emption of space. Some barnacle species tend to settle near conspecifics , Denley & Underwood 1979, Underwood & Denley 1984, but tend not to settle in already crowded conditions (Crisp 1961, Meadows & Campbell 1972, Gaines & Roughgarden 1985, Minchinton & Scheibling 1993. Thus, a barnacle species that arrives first and settles in abundance may have a competitive advantage over a second species that then encounters a crowded substratum and few conspecifics . Patterns of distribution and abundance of barnacle species that display strong conspecific settlement behavior should be governed, at least partly, by priority effects (sensu Paine 1977), and succession involving such barnacles might be expected to follow Connell & Slatyer's (...

Patterns of adult abundance vary with recruitment of an invasive barnacle species on Oahu, Hawaii

“…Zabin (2009) reported anecdotally that recruitment of A. reticulatus was an order of magnitude lower than that of C. proteus in Kaneohe Bay even in treatments from which adult C. proteus were excluded, suggesting that differences between the species in terms of presettlement and/or settlement processes also were important to barnacle abundance there. Thus, processes at several life stages might be expected to contribute to the patterns of abundance of adult barnacles on Oahu.…”

“…Recruitment panels were deployed at three locations: 1) Ala Moana Beach in Mamala Bay on the south shore, 2) Kualoa Beach Park on the northern edge of Kaneohe Bay on the windward side, and 3) Lilipuna Pier in the southern portion of Kaneohe Bay (hereafter Kaneohe Bay), where earlier studies (Zabin, 2009) had been done (Fig. 1, Table 1).…”

“…In fact, Zabin (2009) demonstrated that competition was occurring between C. proteus and A. reticulatus in Kaneohe Bay on the island of Oahu, in the form of substrate pre-emption by the numerically dominant C. proteus. Zabin (2009) hypothesized that this occurred because of the importance of conspecific cues to the settlement of A. reticulatus (Thiyagarajan et al, 2002); these cues were likely not as strong when surfaces were dominated by C. proteus as they were on surfaces on which only A. reticulatus were allowed to settle.…”

“…At semi-protected sites it co-occurs with native barnacles, such as Nesochthamalus intertextus (Darwin, 1854), and in protected waters it can be found in the fouling community with other non-native barnacle species, such as Amphibalanus reticulatus (Utinomi, 1967), which are sometimes highly abundant (Zabin et al, 2007). In fact, Zabin (2009) demonstrated that competition was occurring between C. proteus and A. reticulatus in Kaneohe Bay on the island of Oahu, in the form of substrate pre-emption by the numerically dominant C. proteus. Zabin (2009) hypothesized that this occurred because of the importance of conspecific cues to the settlement of A. reticulatus (Thiyagarajan et al, 2002); these cues were likely not as strong when surfaces were dominated by C. proteus as they were on surfaces on which only A. reticulatus were allowed to settle.…”

Early phase of the invasion of Balanus glandula along the coast of Eastern Hokkaido: changes in abundance, distribution, and recruitment

“…At control plots, N. lima has been commonly found, but it was rarely found at recruitment plots (Takashi Noda, personal observation). Actually, the absence of the introduced barnacles often reflects inhibition associated with interactions with endemic species, such as competition (Zabin 2009) and predation (Laird and Griffiths 2008;Sanford and Swezey 2008).…”