TY - JOUR
T1 - The distribution of the invasive non-native gastropod Crepidula fornicata in the Milford Haven Waterway, its northernmost population along the west coast of Britain
AU - Bohn, Katrin
AU - Richardson, Christopher A.
AU - Jenkins, Stuart R.
PY - 2015/8/12
Y1 - 2015/8/12
N2 - The invasive non-native gastropod Crepidula fornicata is well established in the Milford Haven Waterway (MHW) in south-west Wales, UK, since its first introduction to this ria in 1953. Whilst it reaches high densities within the MHW and has extended its range to the south of this ria, there has been very little northward expansion. Here, we report findings of a series of intertidal and subtidal surveys in 2009 and 2010 where we monitored the population density and the vertical distribution of C. fornicata at its northern range limit in Wales (the MHW). We also characterised the composition of the surface substrata of the seabed in the MHW to provide some insight into how the availability of certain settlement substrata may limit its distribution along the west coast of Britain. We found locally very dense aggregations (maximum 2748 ± 3859 individuals m−2, mean ± SD) in the shallow subtidal and low intertidal of the MHW. Subtidally, highest densities were found in areas of high gravel content (grain sizes ~16–256 mm), suggesting that the availability of this substrata type is beneficial for its establishment at a site. In the intertidal, on the other hand, high gravel content was indicative of low C. fornicata abundance, possibly because gravelly shores are an indicator of very exposed conditions that, at least in the intertidal, may result in high levels of early post-settlement mortality and low recruitment. C. fornicata was absent from the entrance of the MHW, possibly due to the lack of suitable settlement substrata. The presence of substantial populations in the MHW suggests that C. fornicata’s population growth and potential expansion in Welsh coastal waters is not fully limited by prevailing environmental conditions in the region, but that other processes may affect its local distribution.
AB - The invasive non-native gastropod Crepidula fornicata is well established in the Milford Haven Waterway (MHW) in south-west Wales, UK, since its first introduction to this ria in 1953. Whilst it reaches high densities within the MHW and has extended its range to the south of this ria, there has been very little northward expansion. Here, we report findings of a series of intertidal and subtidal surveys in 2009 and 2010 where we monitored the population density and the vertical distribution of C. fornicata at its northern range limit in Wales (the MHW). We also characterised the composition of the surface substrata of the seabed in the MHW to provide some insight into how the availability of certain settlement substrata may limit its distribution along the west coast of Britain. We found locally very dense aggregations (maximum 2748 ± 3859 individuals m−2, mean ± SD) in the shallow subtidal and low intertidal of the MHW. Subtidally, highest densities were found in areas of high gravel content (grain sizes ~16–256 mm), suggesting that the availability of this substrata type is beneficial for its establishment at a site. In the intertidal, on the other hand, high gravel content was indicative of low C. fornicata abundance, possibly because gravelly shores are an indicator of very exposed conditions that, at least in the intertidal, may result in high levels of early post-settlement mortality and low recruitment. C. fornicata was absent from the entrance of the MHW, possibly due to the lack of suitable settlement substrata. The presence of substantial populations in the MHW suggests that C. fornicata’s population growth and potential expansion in Welsh coastal waters is not fully limited by prevailing environmental conditions in the region, but that other processes may affect its local distribution.
KW - Crepidula fornicata
KW - Milford Haven Waterway
KW - Northern range limit
KW - Settlement substrata
KW - Vertical zonation
UR - http://www.scopus.com/inward/record.url?scp=84946492785&partnerID=8YFLogxK
U2 - 10.1007/s10152-015-0439-2
DO - 10.1007/s10152-015-0439-2
M3 - Article
AN - SCOPUS:84946492785
SN - 1438-387X
VL - 69
SP - 313
EP - 325
JO - Helgoland Marine Research
JF - Helgoland Marine Research
IS - 4
ER -