Benthic community structure and water column characteristics at two sites in the Kermadec Islands Marine Reserve, New Zealand

Abstract

The Kermadec Islands Marine Reserve (KIMR), which is located at 30°S, is New Zealand's largest marine reserve at 748 000 ha, and its biota is composed of a mix of warm temperate, subtropical, and tropical species. A depth-stratified ecological survey was conducted of the abundance and percentage cover of macrobenthic species and of the water column at two sites (Meyer Island and West Chanter Island), 2km apart. Significant differences in benthic community structure and in water column turbidity and chlorophyll concentrations were observed between the two sites despite their proximity and physical similarity. Compared with other "snapshot" surveys of benthic community structure at sites within the KIMR there was a high degree of similarity among the species observed, but often a low degree of similarity in species abundance or percentage cover as a function of depth. We suggest that despite its isolation and the degree of difficulty of working at this location, a full-scale ecological survey of the coastal marine biota of the KIMR is warranted to better understand New Zealand's subtropical marine biota and its affinities with other marine biotas of the South Pacific.

Evaluating edge-of-range genetic patterns for tropical echinoderms, <I>Acanthaster planci</I> and <I>Tripneustes gratilla</I>, of the Kermadec Islands, southwest Pacific

“…The islands are geologically young, having originated only 1.8-3 Ma and provide marginal habitat for tropical marine species (Watt 1975). Despite falling within New Zealand's largest marine reserve (Gardner et al 2006), the transitional coral-algal community of the islands is relatively understudied. Genetic patterns and affinities of the islands' marine biota have mostly been addressed above the species level (e.g., algae, Heesch et al 2009;coral symbionts, Wicks et al 2010b), or for subtropical (neritid snail, spencer et al 2007) and endemic species (limpets, Wood and Gardner 2007).…”

“…The pelagic larvae of T. gratilla are known to disperse for at least 18 d (Mortensen 1937), and those of A. planci typically survive up to 28 d in the pelagic environment (Yamaguchi 1973). since the first published records of A. planci (McKnight 1978) and T. gratilla [Farquhar 1897;formerly Tripneustes variegatus (Leske, 1778)] at the Kermadec Islands, both species have been repeatedly recorded at the island group (A. planci: schiel et al 1986, Francis et al 1987, cole et al 1992, brook 1999, Gardner et al 2006T. gratilla: McKnight 1968, schiel et al 1986, cole et al 1992, Gardner et al 2006, including observations of new recruits (richards and Liggins in press).…”

“…since the first published records of A. planci (McKnight 1978) and T. gratilla [Farquhar 1897;formerly Tripneustes variegatus (Leske, 1778)] at the Kermadec Islands, both species have been repeatedly recorded at the island group (A. planci: schiel et al 1986, Francis et al 1987, cole et al 1992, brook 1999, Gardner et al 2006T. gratilla: McKnight 1968, schiel et al 1986, cole et al 1992, Gardner et al 2006, including observations of new recruits (richards and Liggins in press). Acanthaster planci and T. gratilla are particularly abundant around the islets of raoul Island (the northernmost island of the Kermadec Islands); the density of A. planci was recently estimated to be >80 individuals per hectare (richards and Liggins in press) and T. gratilla was present in an estimated similar abundance (L Liggins unpubl data).…”

Correlation between pelagic larval duration and realised dispersal: long-distance genetic connectivity between northern New Zealand and the Kermadec Islands archipelago

“…These regions range from cool temperate, through warm temperate, to subtropical, with the associated environmental variability inherent in such regional differences. Indeed, the Kermadec Islands biota has been recognised as unique, with a marine environment providing important links between the temperate waters of the coasts of New Zealand and the subtropical and tropical waters of Australia and Fiji and Tonga, respectively (Gardner et al 2006 and references therein). The high levels of gene flow between the Kermadec Islands and northern New Zealand, coupled with the absence of stepping stone dispersal and transient adaptation/selection, suggest a significant degree of tolerance to environmental variation in the larvae, juveniles and adults of N. melanotragus.…”

“…They are divided into three groups: the northern group with Raoul Island and its outlying islets; the middle group with Curtis, Cheeseman and Macauley Islands; the southern group with L'Esperance Rock and Havre Rock (Gardner et al 2006). (Fig.…”