Abstract: Tropical dry forest ecosystems are among the most endangered ecosystems globally. In Hawai‘i, dry forest species are under threat due to habitat destruction, invasive species, and a loss of mutualisms including pollinators. Understanding the pollination biology of species at risk can inform conservation strategies. This study aimed to identify the breeding system and types of floral visitors to Erythrina sandwicensis (Fabaceae) or wiliwili, an iconic Hawaiian tree in decline and with little regeneration. We conducted hand-pollination trials and observed visitors in two sites: a botanical garden and a forest site. We compared fruit set, seed set, seed germination, seedling growth rate, and seedling size across four pollination treatments: open control, autogamy, geitonogamy, and xenogamy. We found that wiliwili is visited by a novel suite of non-native visitors. All treatments produced seeds, but the xenogamous (cross) treatment produced significantly more fruit and seeds than the control or other treatments. Seedlings produced from cross-pollinated treatments were also taller and had wider basal diameters after twenty-eight days of growth. These results indicate that wiliwili employs a mixed-mating system, and that trees are pollen limited. Enhancing current populations of wiliwili to promote cross-pollination could help increase population regeneration.
{"title":"Pollination Biology of an Endemic Hawaiian Tree, Erythrina sandwicensis (Fabaceae: Papilionoideae), in a Novel Ecosystem1","authors":"Emily F. Grave, Timothy I. Kroessig, T. Ticktin","doi":"10.2984/75.3.1","DOIUrl":"https://doi.org/10.2984/75.3.1","url":null,"abstract":"Abstract: Tropical dry forest ecosystems are among the most endangered ecosystems globally. In Hawai‘i, dry forest species are under threat due to habitat destruction, invasive species, and a loss of mutualisms including pollinators. Understanding the pollination biology of species at risk can inform conservation strategies. This study aimed to identify the breeding system and types of floral visitors to Erythrina sandwicensis (Fabaceae) or wiliwili, an iconic Hawaiian tree in decline and with little regeneration. We conducted hand-pollination trials and observed visitors in two sites: a botanical garden and a forest site. We compared fruit set, seed set, seed germination, seedling growth rate, and seedling size across four pollination treatments: open control, autogamy, geitonogamy, and xenogamy. We found that wiliwili is visited by a novel suite of non-native visitors. All treatments produced seeds, but the xenogamous (cross) treatment produced significantly more fruit and seeds than the control or other treatments. Seedlings produced from cross-pollinated treatments were also taller and had wider basal diameters after twenty-eight days of growth. These results indicate that wiliwili employs a mixed-mating system, and that trees are pollen limited. Enhancing current populations of wiliwili to promote cross-pollination could help increase population regeneration.","PeriodicalId":54650,"journal":{"name":"Pacific Science","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43592242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract: There is little known about cetaceans in the waters of Papua New Guinea (PNG). Here we present findings from the first two sets of cetacean sighting and acoustic surveys conducted within the Admiralty Island group in the northern Bismarck Sea. More than 1,000 cetaceans were sighted during our boat-based surveys–the most common being spinner dolphins (Stenella longirostris), followed by pantropical spotted dolphins (Stenella attenuata), short-finned pilot whales (Globicephala macrorhynchus), and sperm whales (Physeter macrocephalus). The relative group size of spinner dolphins was different between years with group sizes in 2010 being significantly lower (median = 15, range = 2–50) than those recorded in 2013 (median = 50, range = 5–100). The presence of large aggregations of spinner dolphins (including calves) as well as sightings of Vulnerable sperm whales suggest the northern Bismarck Sea as an area of conservation importance for cetaceans. Our surveys also provide useful baseline data for a variety of marine protected area planning processes and management initiatives that are ongoing in PNG.
{"title":"Cetaceans of the Northern Bismarck Sea, Papua New Guinea1","authors":"Cara Miller, Vagi Rei","doi":"10.2984/75.3.7","DOIUrl":"https://doi.org/10.2984/75.3.7","url":null,"abstract":"Abstract: There is little known about cetaceans in the waters of Papua New Guinea (PNG). Here we present findings from the first two sets of cetacean sighting and acoustic surveys conducted within the Admiralty Island group in the northern Bismarck Sea. More than 1,000 cetaceans were sighted during our boat-based surveys–the most common being spinner dolphins (Stenella longirostris), followed by pantropical spotted dolphins (Stenella attenuata), short-finned pilot whales (Globicephala macrorhynchus), and sperm whales (Physeter macrocephalus). The relative group size of spinner dolphins was different between years with group sizes in 2010 being significantly lower (median = 15, range = 2–50) than those recorded in 2013 (median = 50, range = 5–100). The presence of large aggregations of spinner dolphins (including calves) as well as sightings of Vulnerable sperm whales suggest the northern Bismarck Sea as an area of conservation importance for cetaceans. Our surveys also provide useful baseline data for a variety of marine protected area planning processes and management initiatives that are ongoing in PNG.","PeriodicalId":54650,"journal":{"name":"Pacific Science","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41914642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wieteke A. Holthuijzen, Susan L. Durham, E. Flint, J. Plissner, K. Rosenberger, C. Wolf, H. Jones
Abstract: Invertebrates are key to island ecosystems but impacts from invasive mammalian predators are not well documented or understood. Given this knowledge gap, we studied terrestrial arthropod communities in the presence of a common invasive rodent (house mice, Mus musculus) on a subtropical atoll—Midway Atoll National Wildlife Refuge (MANWR). Here, invasive mice recently began to attack and depredate nesting seabirds, prompting planning for a future mouse eradication. However, uncertainty remains regarding the ecosystem's response to mouse removal. As part of a pre-eradication investigation, we conducted a baseline survey of MANWR's arthropod community structure and diversity (at order level), comparing islands with and without mice. From April 2018 to February 2020, we used pitfall traps to monitor ground-dwelling arthropods on MANWR's Sand Island (mice present) and Eastern Island (mice absent). During our study, we captured over 450,000 specimens from 24 taxonomic units. Arthropods on MANWR form six community clusters and differ between islands and habitats. Richness is relatively similar among clusters and islands, but diversity of common and dominant arthropod taxa is significantly higher on Sand Island, as well as in anthropogenically-built habitats. Weather is not a strong environmental driver of arthropod communities; community structure and diversity vary only slightly throughout the year. Additionally, anthropomorphic landscape-level alteration of MANWR may still influence arthropod communities today. Continued monitoring and research will provide better insight into how arthropod communities recover following invasive mouse eradications. Our study contributes to the body of knowledge of arthropods in the Northwestern Hawaiian Islands, arthropod community ecology, and potential mouse impacts on islands.
{"title":"Fly on the Wall: Comparing Arthropod Communities between Islands with and without House Mice (Mus musculus)1","authors":"Wieteke A. Holthuijzen, Susan L. Durham, E. Flint, J. Plissner, K. Rosenberger, C. Wolf, H. Jones","doi":"10.2984/75.3.6","DOIUrl":"https://doi.org/10.2984/75.3.6","url":null,"abstract":"Abstract: Invertebrates are key to island ecosystems but impacts from invasive mammalian predators are not well documented or understood. Given this knowledge gap, we studied terrestrial arthropod communities in the presence of a common invasive rodent (house mice, Mus musculus) on a subtropical atoll—Midway Atoll National Wildlife Refuge (MANWR). Here, invasive mice recently began to attack and depredate nesting seabirds, prompting planning for a future mouse eradication. However, uncertainty remains regarding the ecosystem's response to mouse removal. As part of a pre-eradication investigation, we conducted a baseline survey of MANWR's arthropod community structure and diversity (at order level), comparing islands with and without mice. From April 2018 to February 2020, we used pitfall traps to monitor ground-dwelling arthropods on MANWR's Sand Island (mice present) and Eastern Island (mice absent). During our study, we captured over 450,000 specimens from 24 taxonomic units. Arthropods on MANWR form six community clusters and differ between islands and habitats. Richness is relatively similar among clusters and islands, but diversity of common and dominant arthropod taxa is significantly higher on Sand Island, as well as in anthropogenically-built habitats. Weather is not a strong environmental driver of arthropod communities; community structure and diversity vary only slightly throughout the year. Additionally, anthropomorphic landscape-level alteration of MANWR may still influence arthropod communities today. Continued monitoring and research will provide better insight into how arthropod communities recover following invasive mouse eradications. Our study contributes to the body of knowledge of arthropods in the Northwestern Hawaiian Islands, arthropod community ecology, and potential mouse impacts on islands.","PeriodicalId":54650,"journal":{"name":"Pacific Science","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44830468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract: Visual census surveys utilizing a distance sampling approach were undertaken in Saipan Lagoon to determine the density of humphead wrasse (HHW) in four shallow water habitats, and compared to observations in the Saipan nighttime commercial spear fishery. Fish observed from the survey ranged in total length from 6.5 to 35 cm total length, generally smaller than the range of fish sampled from the commercial fishery of 16 to 47 cm total length. The majority of survey observations occurred in the central and northern part of Saipan Lagoon, which correlated with capture locations documented in the commercial fishery landings. Analysis of contemporary and historical commercial fishery data showed that HHW could not be considered primary fishery target species. Distance sampling results indicated that coral/hard bottom and Enhalus acroroides seagrass were the habitats most important to HHW, as reflected by higher density estimates. The use of distance sampling was useful in estimating the spatial distribution and density of HHW, and should be considered when assessing other rare marine finfish species.
{"title":"Evaluation of the Humphead Wrasse, Cheilinus undulatus, in Shallow Water Habitats in Saipan Lagoon, Commonwealth of the Northern Mariana Islands1","authors":"M. Trianni, John E. Gourley, S. Vogt","doi":"10.2984/75.3.4","DOIUrl":"https://doi.org/10.2984/75.3.4","url":null,"abstract":"Abstract: Visual census surveys utilizing a distance sampling approach were undertaken in Saipan Lagoon to determine the density of humphead wrasse (HHW) in four shallow water habitats, and compared to observations in the Saipan nighttime commercial spear fishery. Fish observed from the survey ranged in total length from 6.5 to 35 cm total length, generally smaller than the range of fish sampled from the commercial fishery of 16 to 47 cm total length. The majority of survey observations occurred in the central and northern part of Saipan Lagoon, which correlated with capture locations documented in the commercial fishery landings. Analysis of contemporary and historical commercial fishery data showed that HHW could not be considered primary fishery target species. Distance sampling results indicated that coral/hard bottom and Enhalus acroroides seagrass were the habitats most important to HHW, as reflected by higher density estimates. The use of distance sampling was useful in estimating the spatial distribution and density of HHW, and should be considered when assessing other rare marine finfish species.","PeriodicalId":54650,"journal":{"name":"Pacific Science","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45026204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Honour Booth, N. Lautze, Diamond K. Tachera, Daniel Dores
Abstract: While the influence of elevation and seasonal variation on isotopic composition has been studied on Maui, Hawai‘i Island, and O‘ahu (Scholl et al. 1996, Scholl et al. 2002, Scholl et al. 2007, Dores et al. 2020, Fackrell et al. 2020, Tachera et al. 2021), this work is the first to investigate event-based precipitation in detail on the island of O‘ahu. The stable isotopic composition of water has been used to track the movement of water within the hydrosphere, to investigate the type and origin of a rainfall event, and elevation of collection, among other characteristics. Here, we present a high-resolution study of the stable isotopes δ2H and δ18O of precipitation along a compact land-to-sea transect in Waikīkī, a southwest facing region on O‘ahu. The study provides a unique, in-depth investigation into the nature of individual storm events, and how they contribute to a larger seasonal climatic pattern. Monthly precipitation samples were collected at three sites along the transect from December 2017 to March 2019 and event-based samples were collected at the Makai site from October 2018 to February 2019. Storm direction, temperature, and relative humidity were recorded for each event-based sample. Results suggest that evaporative conditions at different elevations influence the isotopic composition of precipitation, either through net addition as moisture recycling, or net loss of evaporated water. The spatial distribution of these patterns from site to site illustrates the extreme heterogeneity of Hawaiian watersheds.
摘要：虽然已经在毛伊岛、夏威夷岛和奥阿胡岛研究了海拔和季节变化对同位素组成的影响（Scholl等人，1996年，Scholl et al.2002年，Schol et al.2007年，Dores et al.2020，Fackrell et al.2020年，Tachera et al.2021），但这项工作是首次详细研究奥阿胡岛基于事件的降水。水的稳定同位素组成已被用于跟踪水圈内的水的运动，研究降雨事件的类型和起源，以及收集的高程等特征。在这里，我们对O’ahu上面向西南的Waikīkī地区一条紧凑的陆海样带上降水的稳定同位素δ2H和δ18O进行了高分辨率研究。这项研究对单个风暴事件的性质以及它们如何促成更大的季节性气候模式进行了独特而深入的调查。2017年12月至2019年3月，在样带沿线的三个地点收集了月度降水样本，2018年10月至2019月，在马凯地点收集了基于事件的样本。记录每个基于事件的样本的风暴方向、温度和相对湿度。结果表明，不同海拔高度的蒸发条件通过水分循环的净添加或蒸发水的净损失影响降水的同位素组成。这些模式在不同地点的空间分布说明了夏威夷流域的极端异质性。
{"title":"Event-Based Stable Isotope Analysis of Precipitation Along a High Resolution Transect on the South Face of O‘ahu, Hawai‘i","authors":"Honour Booth, N. Lautze, Diamond K. Tachera, Daniel Dores","doi":"10.2984/75.3.9","DOIUrl":"https://doi.org/10.2984/75.3.9","url":null,"abstract":"Abstract: While the influence of elevation and seasonal variation on isotopic composition has been studied on Maui, Hawai‘i Island, and O‘ahu (Scholl et al. 1996, Scholl et al. 2002, Scholl et al. 2007, Dores et al. 2020, Fackrell et al. 2020, Tachera et al. 2021), this work is the first to investigate event-based precipitation in detail on the island of O‘ahu. The stable isotopic composition of water has been used to track the movement of water within the hydrosphere, to investigate the type and origin of a rainfall event, and elevation of collection, among other characteristics. Here, we present a high-resolution study of the stable isotopes δ2H and δ18O of precipitation along a compact land-to-sea transect in Waikīkī, a southwest facing region on O‘ahu. The study provides a unique, in-depth investigation into the nature of individual storm events, and how they contribute to a larger seasonal climatic pattern. Monthly precipitation samples were collected at three sites along the transect from December 2017 to March 2019 and event-based samples were collected at the Makai site from October 2018 to February 2019. Storm direction, temperature, and relative humidity were recorded for each event-based sample. Results suggest that evaporative conditions at different elevations influence the isotopic composition of precipitation, either through net addition as moisture recycling, or net loss of evaporated water. The spatial distribution of these patterns from site to site illustrates the extreme heterogeneity of Hawaiian watersheds.","PeriodicalId":54650,"journal":{"name":"Pacific Science","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47034251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Lavery, L. Decicco, Jonathan Q. Richmond, Ikuo G. Tigulu, Michael J. Andersen, D. Boseto, R. Moyle
Abstract: Remote oceanic islands have high potential to harbor unique fauna and flora, but opportunities to conduct in-depth biotic surveys are often limited. Furthermore, underrepresentation of existing biodiversity in the literature has the potential to detract from conservation planning and action. Between 18 and 29 October 2018, we surveyed the terrestrial vertebrates of East Rennell, a UNESCO World Heritage Site in Solomon Islands. We documented 56 species, including 15 squamates, 13 mammals, and 38 birds, and present four new vertebrate records for the island: Stephan's emerald dove (Chalcophaps stephani), Maluku myotis (Myotis moluccarum), littoral skink (Emoia atrocostata) and brahminy blindsnake (Indotyphlops braminus). East Rennell was designated a World Heritage site for its significant on-going ecological and biological processes, and importance for the study of island biogeography. The new records presented here provide evidence that continued field studies combined with DNA analysis will continue to uncover even greater endemic biodiversity. Rennell is currently experiencing major habitat destruction in parts of the island that are not under World Heritage protection, and we anticipate collateral damage will likely extend into protected areas. Our survey also underscores the incredible vertebrate biodiversity that stands to be lost unless conservation actions and local community needs are intertwined to promote beneficial outcomes on both fronts.
{"title":"New Faunal Records from a World Heritage Site in Danger: Rennell Island, Solomon Islands1","authors":"T. Lavery, L. Decicco, Jonathan Q. Richmond, Ikuo G. Tigulu, Michael J. Andersen, D. Boseto, R. Moyle","doi":"10.2984/75.3.8","DOIUrl":"https://doi.org/10.2984/75.3.8","url":null,"abstract":"Abstract: Remote oceanic islands have high potential to harbor unique fauna and flora, but opportunities to conduct in-depth biotic surveys are often limited. Furthermore, underrepresentation of existing biodiversity in the literature has the potential to detract from conservation planning and action. Between 18 and 29 October 2018, we surveyed the terrestrial vertebrates of East Rennell, a UNESCO World Heritage Site in Solomon Islands. We documented 56 species, including 15 squamates, 13 mammals, and 38 birds, and present four new vertebrate records for the island: Stephan's emerald dove (Chalcophaps stephani), Maluku myotis (Myotis moluccarum), littoral skink (Emoia atrocostata) and brahminy blindsnake (Indotyphlops braminus). East Rennell was designated a World Heritage site for its significant on-going ecological and biological processes, and importance for the study of island biogeography. The new records presented here provide evidence that continued field studies combined with DNA analysis will continue to uncover even greater endemic biodiversity. Rennell is currently experiencing major habitat destruction in parts of the island that are not under World Heritage protection, and we anticipate collateral damage will likely extend into protected areas. Our survey also underscores the incredible vertebrate biodiversity that stands to be lost unless conservation actions and local community needs are intertwined to promote beneficial outcomes on both fronts.","PeriodicalId":54650,"journal":{"name":"Pacific Science","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48568318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract:Reports on the taxonomy and distribution of the amphipod crustacean Leucothoe nagatai Ishimaru, 1985, are discussed including significant range extensions from the type locality in the Sea of Japan. This research was based on existing museum specimens, and in situ collections of new material. Originally described from the branchial chamber of the solitary ascidian Styela plicata (Lesueur, 1823), several new ascidian and sponges host species from California and New Zealand are documented for L. nagatai. Molecular studies confirm that northern and southern hemisphere populations are genetically indistinguishable. Color patterns in live and freshly preserved specimens of L. nagatai are diagnostic across its geographic range aiding in identification by nontaxonomists. Feeding habits of leucothoids within their invertebrate hosts are elucidated and discussed. Figures and plates of known invertebrate hosts, color patterns, and taxonomic structures are included.
{"title":"Bi-Hemispheric Distribution and Ecology of the Commensal Amphipod Leucothoe nagatai Ishimaru, 1985 (Crustacea: Leucothoidae)","authors":"J. Thomas, Donald B. Cadien, K. White","doi":"10.2984/75.3.2","DOIUrl":"https://doi.org/10.2984/75.3.2","url":null,"abstract":"Abstract:Reports on the taxonomy and distribution of the amphipod crustacean Leucothoe nagatai Ishimaru, 1985, are discussed including significant range extensions from the type locality in the Sea of Japan. This research was based on existing museum specimens, and in situ collections of new material. Originally described from the branchial chamber of the solitary ascidian Styela plicata (Lesueur, 1823), several new ascidian and sponges host species from California and New Zealand are documented for L. nagatai. Molecular studies confirm that northern and southern hemisphere populations are genetically indistinguishable. Color patterns in live and freshly preserved specimens of L. nagatai are diagnostic across its geographic range aiding in identification by nontaxonomists. Feeding habits of leucothoids within their invertebrate hosts are elucidated and discussed. Figures and plates of known invertebrate hosts, color patterns, and taxonomic structures are included.","PeriodicalId":54650,"journal":{"name":"Pacific Science","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48869052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract: Two introduced invasive red macroalgae, Eucheuma denticulatum (Burman) Collins & Hervey and Gracilaria salicornia C. Ag., progressively declined in abundance in Kāne‘ohe Bay, Hawai‘i, following ∼30 years of increase since their introduction in the mid-1970s. The declines were not the result of biological control or mechanical control efforts, but instead were the result of grazing by native herbivores, probably fishes, as demonstrated by field experiments conducted in 2014 with algal thalli exposed to, and protected from grazing. Two long-term time-series of the abundance of herbivorous fishes at Kāne‘ohe Bay patch and fringing reef sites indicated that the abundance of herbivorous fishes increased from 2007 through 2014 over the period when these macroalgae declined in cover. Analyses of data of algal cover from surveys of Kāne‘ohe Bay reefs carried out between 1996 and 2018 indicate that the declines in E. denticulatum and G. salicornia began in approximately 2008, several years before control programs commenced on some of the reefs in the bay. In addition to intense herbivory, high summer water temperatures in 2014 and 2015 may have contributed to the decline in E. denticulatum. Naturally occurring declines in the abundance of alien invasive marine algal species have rarely been reported in the literature. These reductions in macroalgal abundance are the second instance of decline in invasive macroalgae in Kāne‘ohe Bay since 2006, and have reduced competition between macroalgae and corals on reef flats and reef slopes across the bay.
{"title":"Reduction in Cover of Two Introduced Invasive Macroalgae by Herbivores on Coral Reefs of Kāne‘ohe Bay, Hawai‘i1","authors":"J. Stimson, S. Larned","doi":"10.2984/75.2.9","DOIUrl":"https://doi.org/10.2984/75.2.9","url":null,"abstract":"Abstract: Two introduced invasive red macroalgae, Eucheuma denticulatum (Burman) Collins & Hervey and Gracilaria salicornia C. Ag., progressively declined in abundance in Kāne‘ohe Bay, Hawai‘i, following ∼30 years of increase since their introduction in the mid-1970s. The declines were not the result of biological control or mechanical control efforts, but instead were the result of grazing by native herbivores, probably fishes, as demonstrated by field experiments conducted in 2014 with algal thalli exposed to, and protected from grazing. Two long-term time-series of the abundance of herbivorous fishes at Kāne‘ohe Bay patch and fringing reef sites indicated that the abundance of herbivorous fishes increased from 2007 through 2014 over the period when these macroalgae declined in cover. Analyses of data of algal cover from surveys of Kāne‘ohe Bay reefs carried out between 1996 and 2018 indicate that the declines in E. denticulatum and G. salicornia began in approximately 2008, several years before control programs commenced on some of the reefs in the bay. In addition to intense herbivory, high summer water temperatures in 2014 and 2015 may have contributed to the decline in E. denticulatum. Naturally occurring declines in the abundance of alien invasive marine algal species have rarely been reported in the literature. These reductions in macroalgal abundance are the second instance of decline in invasive macroalgae in Kāne‘ohe Bay since 2006, and have reduced competition between macroalgae and corals on reef flats and reef slopes across the bay.","PeriodicalId":54650,"journal":{"name":"Pacific Science","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45647755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bryan A. Nakahara, A. Demopoulos, Y. Rii, R. Alegado, Kauaoa M. S. Fraiola, C. Smith
Abstract: Mangrove forests are prevalent along tropical/subtropical coastlines and provide valuable ecosystem services including coastline stabilization, storm impact reduction, and enhanced coastal productivity. However, mangroves were absent from the Hawaiian Islands and their introduction to Moloka‘i in 1902 has provided an opportunity to examine their unique influence on coastal landscapes. Previous studies indicate an inability of native detritivores to utilize tannin-rich substrates, yielding poor cycling of mangrove-derived detritus in Hawaiian tidal zones. We hypothesize that in addition to altering detrital inputs, introduced mangroves facilitate the persistence of introduced species in the Hawaiian coastal zone by providing novel habitat for juvenile megafauna. To determine whether mangrove-dominated tidal zones harbor megafaunal assemblages distinct from open sandflats, we sampled in two mangrove (M1 and M2) and two adjacent sandflat (S1 and S2) sites along the southern coast of Moloka‘i, where the most mature mangrove forests occur in Hawai‘i. There were no statistical differences in total abundances between M1 and M2 or S1 and S2; therefore, results from individual deployments were pooled across the sites in order to conduct between-habitat (mangrove vs. sandflat) comparisons. Our mangrove study site had significantly higher abundances of megafauna, including several shrimp and crab species, compared to the sandflat site. The community composition within the mangrove site differed from the sandflat site, including higher abundances of non-native mangrove crabs (Scylla serrata), as well as native fish Bathygobius cocosensis and crustaceans (Thalamita crenata, Palaemon pacificus, P. debilis) than in the sandflat site, indicating that the mangrove site may provide niches for both invasive and native species. In addition, mean body length for several similar species was smaller in the mangrove site than in the sandflat site, suggesting that these mangroves may be providing a habitat for juvenile species. While our study was spatially limited to two mangrove and two adjacent sandflat sites, our results suggest that introduced mangroves in Moloka‘i may support small-bodied, native, and non-native megafauna, influencing coastal Hawaiian trophic dynamics. Our case study provides a baseline for megafaunal fish and invertebrate communities present prior to non-native mangrove removal as well as for monitoring potential community changes following expansion of mangrove habitats due to climate change.
{"title":"Introduced Mangroves along the Coast of Moloka‘i, Hawai‘i may Represent Novel Habitats for Megafaunal Communities","authors":"Bryan A. Nakahara, A. Demopoulos, Y. Rii, R. Alegado, Kauaoa M. S. Fraiola, C. Smith","doi":"10.2984/75.2.4","DOIUrl":"https://doi.org/10.2984/75.2.4","url":null,"abstract":"Abstract: Mangrove forests are prevalent along tropical/subtropical coastlines and provide valuable ecosystem services including coastline stabilization, storm impact reduction, and enhanced coastal productivity. However, mangroves were absent from the Hawaiian Islands and their introduction to Moloka‘i in 1902 has provided an opportunity to examine their unique influence on coastal landscapes. Previous studies indicate an inability of native detritivores to utilize tannin-rich substrates, yielding poor cycling of mangrove-derived detritus in Hawaiian tidal zones. We hypothesize that in addition to altering detrital inputs, introduced mangroves facilitate the persistence of introduced species in the Hawaiian coastal zone by providing novel habitat for juvenile megafauna. To determine whether mangrove-dominated tidal zones harbor megafaunal assemblages distinct from open sandflats, we sampled in two mangrove (M1 and M2) and two adjacent sandflat (S1 and S2) sites along the southern coast of Moloka‘i, where the most mature mangrove forests occur in Hawai‘i. There were no statistical differences in total abundances between M1 and M2 or S1 and S2; therefore, results from individual deployments were pooled across the sites in order to conduct between-habitat (mangrove vs. sandflat) comparisons. Our mangrove study site had significantly higher abundances of megafauna, including several shrimp and crab species, compared to the sandflat site. The community composition within the mangrove site differed from the sandflat site, including higher abundances of non-native mangrove crabs (Scylla serrata), as well as native fish Bathygobius cocosensis and crustaceans (Thalamita crenata, Palaemon pacificus, P. debilis) than in the sandflat site, indicating that the mangrove site may provide niches for both invasive and native species. In addition, mean body length for several similar species was smaller in the mangrove site than in the sandflat site, suggesting that these mangroves may be providing a habitat for juvenile species. While our study was spatially limited to two mangrove and two adjacent sandflat sites, our results suggest that introduced mangroves in Moloka‘i may support small-bodied, native, and non-native megafauna, influencing coastal Hawaiian trophic dynamics. Our case study provides a baseline for megafaunal fish and invertebrate communities present prior to non-native mangrove removal as well as for monitoring potential community changes following expansion of mangrove habitats due to climate change.","PeriodicalId":54650,"journal":{"name":"Pacific Science","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43073953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Brandie A. Colwell, Ronald P Kittle, Renee L. Corpuz, K. McDERMID
Abstract: Ruppia cf. maritima is one of the few native Hawaiian brackish water flowering plants, but its identity has never been examined using genetic analysis. The ability of this seagrass to tolerate a wide range of salinities and temperatures is reflected in its morphological variability among locations worldwide. Three populations on the island of Hawai‘i were sampled, and molecular analyses of the nuclear gene ITS and two chloroplast genes trnH-psbA and rbcL were used to examine the identity of Hawaiian Ruppia. Concatenated analyses showed that the populations contained little intra- or interpopulation variability, and indicated greatest genetic similarity to specimens from Japan, India, Vietnam, and Africa. Slight variations in tree topologies were present among the individual nuclear and two plastid markers; however, all Hawaiian specimens nested within other sequences reported as R. maritima. Molecular phylogenetic analyses demonstrate that there are multiple clades of samples from around the world labeled as R. maritima, and that the Hawaiian samples are allied with one of these clades. The geographic isolation and geologic age of each Hawaiian island, as well as the disjunct distribution of Ruppia populations among islands and within each island suggest a multiplex biogeography and evolutionary history of Hawaiian Ruppia.
{"title":"Molecular Systematics of the Native Seagrass, Ruppia cf. Maritima (Ruppiaceae, Alismatales), on Hawai‘i Island1","authors":"Brandie A. Colwell, Ronald P Kittle, Renee L. Corpuz, K. McDERMID","doi":"10.2984/75.2.7","DOIUrl":"https://doi.org/10.2984/75.2.7","url":null,"abstract":"Abstract: Ruppia cf. maritima is one of the few native Hawaiian brackish water flowering plants, but its identity has never been examined using genetic analysis. The ability of this seagrass to tolerate a wide range of salinities and temperatures is reflected in its morphological variability among locations worldwide. Three populations on the island of Hawai‘i were sampled, and molecular analyses of the nuclear gene ITS and two chloroplast genes trnH-psbA and rbcL were used to examine the identity of Hawaiian Ruppia. Concatenated analyses showed that the populations contained little intra- or interpopulation variability, and indicated greatest genetic similarity to specimens from Japan, India, Vietnam, and Africa. Slight variations in tree topologies were present among the individual nuclear and two plastid markers; however, all Hawaiian specimens nested within other sequences reported as R. maritima. Molecular phylogenetic analyses demonstrate that there are multiple clades of samples from around the world labeled as R. maritima, and that the Hawaiian samples are allied with one of these clades. The geographic isolation and geologic age of each Hawaiian island, as well as the disjunct distribution of Ruppia populations among islands and within each island suggest a multiplex biogeography and evolutionary history of Hawaiian Ruppia.","PeriodicalId":54650,"journal":{"name":"Pacific Science","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49607225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：