Squat lobster assemblages on seamounts differ from some, but not all, deep‐sea habitats of comparable depth

Abstract

This study was carried out to test the hypothesis that benthic communities on seamounts are distinct from those of other deep‐sea habitats at comparable depths. Analysis of the squat lobster fauna of deep‐sea habitats in the Southwestern Pacific revealed that the species composition of assemblages on seamounts was not statistically dissimilar from assemblages on slope and plateau habitat at comparable depths. However, compositional differences were observed between seamount and rise and ridge habitat. Differences in assemblage composition between seamount and ridge habitat were statistically significant for two of the four ridge systems examined. Assemblages on seamounts that were distinct from non‐seamount ridge habitat were typically dominated by small‐bodied species with an abbreviated larval stage. Various environmental variables were correlated with the observed assemblage patterns observed; depth‐related variables may account for differences between seamount and rise assemblages, whilst differences in POC flux likely play a role in determining the assemblage compositional patterns between seamount and non‐seamount ridge habitat. Extensive pre‐analysis data treatment was required to ensure that multivariate analyses of assemblage data from seamount and non‐seamount habitats were robust. Our results confirm the findings of recent studies that found no compositional differences in assemblages from seamount and slope habitats, and support the idea that dissimilarity between seamount assemblages on different ridge systems increases with geographic distance. Further research will be required before the generality of these findings can be confirmed.

Seamount benthos in a cobalt‐rich crust region of the central Pacific: conservation challenges for future seabed mining

“…These drivers include hydrographic conditions as well as seafloor characteristics -a result similar to comparable studies elsewhere (e.g. O'Hara et al, 2010; Rowden et al, 2010b). Of particular interest for this study was that the prevalence of Mn-crust was identified as one potential determinant of benthic assemblage structure on seamounts in the region.…”

“…In the South-west Pacific, the relationship between spatial separation of seamounts and biotic similarity of the fauna has been examined for mixed invertebrate assemblages at distances up to 3000 km by Richer de Forges et al (2000). Subsequent studies on molluscs (Samadi et al, 2006;Castelin et al, 2010Castelin et al, , 2011, galatheids (Rowden et al, 2010b) and ophiuroids (O'Hara et al, 2008) in the same general region reported an effect of geographic distances of 100s to 1000s of km on the degree of resemblance among assemblages. O'Hara et al (2010) found that species composition changed along the 950 km Vitoria-Trindade seamount chain in the western South Atlantic.…”

Diversity, distribution and spatial structure of the cold-water coral fauna of the Azores (NE Atlantic)

“…There are also major common components with the western North Atlantic (33 %), the Canary and Cape Verde islands (30 %) and the seamounts located south of the Azores and between mainland Portugal and Madeira (28 %). Several studies have previously reported high similarities between seamount faunas and those from the nearest continental margin (Wilson and Kaufman, 1987;McClain et al, 2009a;Rowden et al, 2010). In the northeast Atlantic, Surugiu et al (2008) found that 73 % of the polychaetes from seamounts off the Iberian and African coasts and south of the Azores were shared with the neighbouring continental margins.Ávila and Malaquias (2003) reported that a high proportion of the molluscan fauna inhabiting Ormonde Seamount has strong affinities with the nearby Portuguese continental shelf, the Mediterranean and the Macaronesian archipelagos of Madeira and the Canaries.…”

Habitat Differences in Deep-Sea Megafaunal Communities off New Zealand: Implications for Vulnerability to Anthropogenic Disturbance and Management

“…Food availability is a major driver of structure in deep-sea benthic communities at regional scales, where elevated levels (up to a point) increase the overall faunal abundance and relative abundance of particular taxa (Levin et al, 2001;Smith et al, 2008). Rowden et al (2010b) also attributed the regional differences they observed in squat lobster communities to the relative levels of particulate organic matter flux to the seafloor (another proxy for food availability). In the present study, substrate diversity was also markedly different between regions, being greater at canyons and seamounts in the Bay of Plenty, and at slopes in the Hikurangi Margin region.…”

“…Studies have shown that these feature-scales of habitat heterogeneity influence the biodiversity patterns (abundance, biomass and diversity) of megafauna on continental margins due to differences in various local environmental factors (e.g., canyon versus open slope- Sardà et al, 1994;Ramírez-Llodra et al, 2008;Vetter et al, 2010; seamount versus slope- Rowden et al, 2010a;Tecchio et al, 2013). However, few studies have determined and reported the level of community similarity (species turnover or β-diversity) among the megafaunal communities that inhabit these deep-sea habitats Ramirez-Llodra et al, 2010;Rowden et al, 2010b), and only one to our knowledge has used community similarity to explicitly assess the degree of connectivity between habitats (Kelly et al, 2010-which included megafauna), and none to assess their potential vulnerability to anthropogenic disturbance.…”