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

Abstract

To understand the patterns and processes associated with the population dynamics of Balanus glandula during the early phase of invasion along the Pacific coast of eastern Hokkaido, population surveys were conducted from 2002 to 2011 at five shores, each consisting of five paired plots (scraped recruitment plot and unscraped establishment plot), along 49 km of coastline located 144 km east of the eastern front of the invasion of this species in 2000. Larval recruitment was first detected in 2004, but the establishment of a population was not observed until 2 years later at the westernmost shore of the study area. Occurrence increased from non-native barnacle present in 4 % of plots in 2006 to 100 % in 2011, but mean coverage remained low (\5 %) in 2011. Most local population coverage fluctuated without indicating clear temporal trends, but coverage in one plot showed a consistent pattern of rapid increase. Local extinctions occurred, but rates of local extinction decreased with time as larval recruitment increased. Lag times between recruitment and establishment occurred for 64 % of the paired plots and ranged from 1 to 4 years. Lag times decreased after 5 years, when larval recruitment increased. These findings suggest that the intensity of larval recruitment determined invasion dynamics during this early phase of the invasion, and the monitoring of recruitment is therefore essential for early detection of invasions by sessile marine organisms and prediction of their range expansion.

Impacts of alien ‘ecosystem engineers’ overwhelm interannual and seasonal shifts in rocky-shore community composition on Marcus Island, South Africa

“…Limpets can remove newly settled barnacles from substrate by consumption or dislodgment, and this effect is intensified when limpet densities are high (Hawkins 1983;Hawkins and Hartnoll 1983;Miller and Carefoot 1989). However, recruitment of the alien barnacle B. glandula on Marcus Island decreased in the years following its invasion, as was also the case in Japan (Rashidul Alam et al 2013). In False Bay, on the southwest coast of South Africa, where the density of native barnacles can reach high levels, the size, density and gonadal output of S. granularis decrease when it is surrounded by barnacles, because the limpet's feeding is inhibited (Branch 1976).…”

Limpet disturbance effects on barnacle recruitment are related to recruitment intensity but not recruit size

“…We conducted this study on the Pacific coast of Hokkaido, Japan. Along this coast, limpets (Lottia cassis) and barnacles (Chthamalus dalli, Balanus glandula) are common organisms that co-occur in rocky mid-intertidal habitats (Nakaoka et al, 2006;Alam et al, 2014;Yorisue, Ellrich & Momota, 2019). Lottia cassis is patchily distributed (Yorisue, personal observations) and forages by grazing algae off the rocky substrate (Tsurpalo, 1995).…”

“…Such limpet disturbance effects (LDEs) can limit barnacle recruitment (Dayton, 1971;Miller & Carefoot, 1989;Menge et al, 2010), which is the appearance of new barnacle individuals (i.e., recruits) that derive from settled and metamorphosed cyprids (Cole et al, 2011). Recruitment is a key demographic variable in barnacle population establishment (Alam et al, 2014) and persistence (Menge & Menge, 2013).…”

“…On this coast, B. glandula has replaced several native barnacle species (Kado & Nanba, 2006). More recently, B. glandula spread to the Pacific coast of Hokkaido, northern Japan (Alam et al, 2014). In Hokkaido, the cyprid carapace length is ca.…”

“…However, observations in several barnacle species suggest that early recruits are slightly smaller than cyprids (Høeg et al, 2012;Maruzzo et al, 2012). In Hokkaido, C. dalli and B. glandula recruitment occurs from May to September, and C. dalli recruitment is typically higher than B. glandula recruitment since B. glandula established on this coast only recently (Alam et al, 2014;Yorisue, Ellrich & Momota, 2019).…”