Diversity at hydrothermal vents

Aim To describe patterns of hydrothermal vent community diversity and dispersion at the intersegment scale (> 100 km). Location The area discussed is an approximately 170 km portion of the Juan de Fuca Ridge, a mid‐ocean ridge in the north‐east Pacific Ocean. Methods Samples of benthic invertebrates from hydrothermal vents on three segments of the Juan de Fuca are examined for community characteristics such as diversity, abundance and distribution. Results Species richness (55 species) and evenness are low. If the macrofauna only are considered, species richness is about 30% lower than when meiofauna are also considered. The geometric series describes the species‐abundance distribution. The relationship between vent species’ distribution and abundance is significantly positive (r² = 0.818; P < 0.001). Alpha diversity is lower in patchy habitat than continuous habitat and gamma diversity is similar for both habitat types. Beta diversity is higher in patchy habitat. Local diversity is linearly related to regional diversity. Main conclusions Species richness is comparable to other highly disturbed systems. The geometric series species abundance model implies some degree of niche pre‐emption in the vent community and is consistent with the suggestion that the geometric series distribution can be found in species‐poor environments that experience harsh conditions and are structured by relatively few environmental factors. Species distribution and abundance are highly correlated. The regional species pool affects local vent diversity. Vent diversity studies should be conducted on at least the ridge scale.