Pacific Science Volume 57, Number 4, 2003
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Pacific Science is a quarterly publication devoted to the biological and physical sciences of the Pacific Region.
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ItemThree New Species of Saccocirrus (Polychaeta: Saccocirridae) from Hawai'i(University of Hawai'i Press, 2003-10)Three new species of saccocirrids from interstitial sand habitats off O'ahu, Hawai'i, are described. Two are from subtidal depths, 9-33 m, and the third is from the intertidal to 3.5 m deep on a fringing reef and at Hanauma Bay, the Marine Life Conservation District and public park. The two deeper-water species, Saccocirrus oahuensis, n. sp. and S. waianaensis, n. sp., have 76-119 and 157-210 segments, respectively; they also have bilateral gonads but lack a pharyngeal pad. The third, S. alanhongi, n. sp., has 35-47 segments, unilateral gonads, and a muscular pharyngeal pad. These species are distinguished from 18 known Saccocirrus spp. by their unique chaetation, number of segments, presence or absence of ventral cilia, and pygidial adhesive structures. Saccocirms oahuensis consumes foraminiferans, and S. alanhongi contained diatoms, unicellular algae, and ostracods. These species add to the interstitial fauna of O'ahu and cooccur with polychaetes Nerilla antennata (Nerillidae) and protodrilids (Protodrilidae), and Kinorhyncha. Saccocirrus alanhongi withstands almost daily disturbance by 600-1200 bathers per day entering the sandy swimming holes in the reef at Hanauma Bay.
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ItemVariation in Structure of the Subcanopy Assemblage Associated with Southern California Populations of the Intertidal Rockweed Silvetia compressa (Fucales)(University of Hawai'i Press, 2003-10)Variation in structure of the subcanopy communities associated with southern California Silvetia compressa (J. Agardh) Serrao, Cho, Boo & Brawley populations was examined at eight sites, including four long-standing intertidal Marine Protected Areas (MPAs). Although sea temperature and salinity showed little variation, maximum wave force and sand influence differed significantly among sites. Seaweed and sessile macroinvertebrate cover and mobile macroinvertebrate densities were determined in 10 quadrats during both autumn 1995 and spring 1996. A total of 111 taxa was distinguished at the eight sites, including 47 macroalgae, 20 sessile macroinvertebrates, and 44 mobile macroinvertebrates; however, only a few species consistently dominated abundances in the subcanopy assemblage. Silvetia compressa cover varied significantly among sites during both sampling periods; cover was significantly greater at all but one site during the autumn. Morphologies of Silvetia compressa thalli were qualitatively similar except at Monarch Bay, where plants were the least densely aggregated and frond lengths were two to three times greater than at other sites. Seaweeds contributed 71.2% of the subcanopy cover averaged over all sites compared with 23.8% sessile macroinvertebrate cover; mobile invertebrate densities averaged 363.9 m-2 over all sites. The three most abundant seaweeds (Pseudolithoderma nigra, Pseudolithophyllum neofarlowii, and Corallina pinnatifolial C. vancouveriensis) and macroinvertebrates (Phragmatopoma californica, Mytilus californianus, and Anthopleura elegantissima) accounted for approximately 67% and 20%, respectively, of total understory cover. The three most abundant mobile macroinvertebrates (Littorina scutulata, Lepidochitona hartwegii, and Macclintockia scabralLottia conus) accounted for nearly 60% of all mobile animals. An average of 27 macrophytes and sessile macroinvertebrates and 19 mobile macroinvertebrates occurred at a site; site H' diversity based on macrophyte and sessile macroinvertebrate cover averaged 1.91; mobile macroinvertebrate H' diversity based on density averaged 2.03. Neither cluster analysis nor multidimensional scaling produced clear site patterns based on geographic location or sampling period; long-standing MPA sites did not form a distinct group and did not differ significantly in community structure from nonhistorical MPAs based on Analysis of Similarity (ANOSIM) tests. Communities representing autumn and spring were more closely associated with each other than with communities from other sites. Differences in community structure were detected among individual sites in all ANOSIM tests despite strong similarities in abundant taxa. ANOSIM tests also showed that understory communities differed between
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ItemMacroalgae from 23 Stream Segments in the Hawaiian Islands(University of Hawai'i Press, 2003-10)Twenty-three stream segments (seven on O'ahu, eight on Kaua'i, and eight on Hawai'i) were sampled for macroalgae in the Hawaiian Islands. Stream segments ranged greatly in size from 1.2 to 40 m in width. Water temperature was uniformly warm (17-24°C), but other chemical parameters differed from site to site (pH 5.5-8.9, specific conductance 20-200 mS . cm^-1 ). Mean species richness per site was 3.9 with one to eight species collected per stream segment. Ninety populations of 42 infrageneric taxa were identified from the Cyanobacteria (19), Chlorophyta (17), Rhodophyta (3), and Chrysophyta (3). The most abundant taxa were Spirogyra sp. 1, Audouinella pygmaea, and Phormidium retzii. All three of these taxa are widespread among the Islands. Other species collected on all three islands were Cloniophora plumosa and Hildenbrandia angolensis. Eighteen taxa are new records for streams and 15 of these for aquatic habitats. Ten of the new records for the Hawaiian Islands were collected on Kaua'i, six on O'ahu, and one on Hawai'i (two new records shared for Kaua'i and O'ahu). The large percentage (36%) of new taxa reported in this study suggests that more research is needed to fully catalog the Hawaiian stream macroalgal diversity. This study extends the number of micro- and macroalgal taxa known from streams in the Hawaiian Islands to 299 infrageneric taxa.
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ItemAnts (Hymenoptera: Formicidae) of Samoa(University of Hawai'i Press, 2003-10)The ants of Samoa have been well studied compared with those of other Pacific island groups. Using Wilson and Taylor's (1967) specimen records and taxonomic analyses and Wilson and Hunt's (1967) list of 61 ant species with reliable records from Samoa as a starting point, we added published, unpublished, and new records of ants collected in Samoa and updated taxonomy. We increased the list of ants from Samoa to 68 species. Of these 68 ant species, 12 species are known only from Samoa or from Samoa and one neighboring island group, 30 species appear to be broader-ranged Pacific natives, and 26 appear to be exotic to the Pacific region. The seven-species increase in the Samoan ant list resulted from the split of Pacific Tetramorium guineense into the exotic T. bicarinatum and the native T. insolens, new records of four exotic species (Cardiocondyla obscurior, Hypoponera opaciceps, Solenopsis geminata, and Tetramorium lanuginosum), and new records of two species of uncertain status (Tetramorium cf. grassii, tentatively considered a native Pacific species, and Monomorium sp., tentatively considered an endemic Samoan form).
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ItemThe Odonata of Kosrae, Eastern Caroline Islands, Micronesia(University of Hawai'i Press, 2003-10)A recent collection of 69 specimens together with survey counts and incidental observations during June-July 2002 provide new information on the odonate fauna of Kosrae, Micronesia. The fauna comprises one zygopteran (Ischnura aurora) and six anisopterans. It appears to have remained stable with no known extinctions or colonizations over the past half century. The fauna is nearly a subset of that of Pohnpei and the islands to the west, and it comprises six widespread weedy species and one endemic, Hemicordulia erico. Upland aquatic habitats appear largely unexploited or underutilized by odonates, and the absence of any Teinobasis species on Kosrae is in marked contrast to the presence of six species on the nearest high island, Pohnpei.