Community structure of hermatypic corals at Pearl and Hermes Atoll, Northwestern Hawaiian Islands: unique conservation challenges within the Hawaiian archipelago

Self Cite

The distribution and abundance of scleractinian corals at Kure Atoll in the Northwestern Hawaiian Islands was determined by georeferenced towed-diver surveys that covered close to 27,000 m 2 of benthic habitat and site-specific surveys at 21 sites during 2000-2003. Three complementary methods (towed-diver surveys, video transects, and photoquadrats) were used to quantify percent cover of corals by genus or species in the fore-reef, back-reef, and lagoon habitats. Three genera, Porites, Pocillopora, and Montipora, accounted for more than 99% of the coral cover throughout the atoll, although their relative abundances vary considerably according to habitat and geographic sector within habitats. Fore-reef communities are dominated by massive and encrusting Porites and by Pocillopora, while the back reef is dominated by Montipora and the lagoon by Porites compressa. All taxa show habitat-specific differences in colony density and sizeclass distributions as assessed through colony counts within belt transects at fixed sites. These demographic data provide the most detailed, spatially comprehensive description of coral communities at Kure Atoll produced to date and can serve as a solid baseline for determining the magnitude and direction of future changes. They are discussed within the context of factors known to affect community development on Hawaiian coral reefs including temperature, wave stress, coral bleaching and other diseases, marine debris, and crown-of-thorns seastars.

Section: Community Development At High Latitudessupporting

confidence: 68%

Community structure of hermatypic corals at Kure Atoll in the northwestern Hawaiian Islands: Stemming the shifting baseline

Kenyon¹,

Dunlap²,

Aeby³

2008

Self Cite

“…Reef-wide patterns of coral cover at Maro Reef vary from those at other locations in the NWHI. At Pearl and Hermes Atoll, coral cover was highest on the fore reef in the northwest and north sectors (~ 24-28%; Kenyon et al, 2007a); at Kure Atoll, coral cover was highest on the fore reef along the arc extending counterclockwise from north to west (~ 11-16%; J. Kenyon, unpubl.…”

Section: Coral Cover and Wave Disturbancementioning

confidence: 99%

Community structure of hermatypic corals at Maro Reef in the northwestern Hawaiian Islands: A unique open atoll

Kenyon¹,

Wilkinson²,

Aeby³

2008

Self Cite

Percent cover of shallow-water (< 20m) scleractinian corals at Maro Reef, an open atoll with no perimeter reef in the Northwestern Hawaiian Islands (NWHI), was quantified from analysis of imagery recorded along more than 81 km of benthic habitat by towed divers and at 18 sites surveyed with video transects and photoquadrats. Colony densities and size class distributions were determined from censuses within belt transects at the same sites. All three methods showed statistically significant differences in total coral cover and relative abundance of coral genera among four geographic sectors characterized by different exposure to prevailing wave regimes. Massive and encrusting growth forms of Porites dominated coral cover and density throughout all sectors, with Montipora the next most dominant genus. Patterns of highest coral cover differed from that of most other classic and open atolls in the NWHI. Populations of Pocillopora, though contributing little to percent cover, attained the largest colony sizes of any reef system in the NWHI surveyed with similar methods. Numerous indicators, including coral percent cover, recovery from bleaching, low coral disease prevalence, rarity of crown-of-thorns seastars, and high larval recruitment rates suggest healthy coral communities at Maro Reef, although the predicted accumulation of marine debris from outside sources remains problematic. These data enable the most comprehensive quantitative description of coral communities at Maro Reef produced to date and are a valuable baseline for assessing change.

“…In contrast, mean scleractinian coral cover from towed-diver surveys between depths of 10 and 12 m on the fore reef (n = 175 frames) was 26.1% (SE 1.4) (data not shown). Estimates of coral cover derived from site-specific surveys generally exceed those derived from towed-diver surveys (Kenyon et al, 2006b(Kenyon et al, , 2007a, because site-specific surveys target hard-bottom communities, whereas broad-scale surveys include more variable substrate. Our estimate of coralline algal cover from towed-diver surveys between depths of 10 and 12 m on the fore reef (18.8%, SE 1.5) also differs from that reported by Sandin et al (2008), ~ 29%.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Coral Communities at Kingman Reef in the Remote Central Pacific Ocean

Kenyon¹,

Maragos²,

Wilkinson³

2010

Self Cite

Kingman Reef, an atoll in the northern Line Islands of the central Pacific, is among the last of the remote locations in the U.S. Pacific to be scientifically explored underwater, and previously published surveys of its benthic reef communities have been limited to the seaward-facing fore-reef habitat. Here, we apply multivariate statistical analyses to data acquired in 2004 from several complementary survey methods that operate at different scales of spatial and taxonomic resolution to characterize the coral communities in 5 habitats, 3 of which are further stratified by geographic sector or depth zone. Coral cover is highest in the small lagoon pool inside the southeast vertex of the perimeter reef, followed by the fore reef, patch reefs, reef flat, and lagoon slope. Benthic communities are more highly variable on the fore reef, but the coral cover and colony abundances are less dominated by a few key genera than in other habitats. While the relative representation of coral taxa varies among habitats, Porites, Fungia, Pocillopora, Sinularia, Turbinaria, Acropora, and Favia all contribute > 10% of the total coral cover in at least one habitat. We provide a list of 188 anthozoan and hydrozoan corals observed at Kingman Reef during survey activities since the year 2000. Coral diversity at Kingman is similar to that at Palmyra Atoll to the south but is high compared to other adjacent atolls and reef islands to the south and west (Phoenix and Line Islands) where data are available. Our spatially widespread surveys that generate independent metrics of benthic cover and coral abundance collectively provide the most comprehensive description of coral communities at Kingman Reef produced to date and also provide an important record by which to monitor the response of this community to changing ocean conditions.