Is seagrass an important nursery habitat for the Caribbean spiny lobster,panulirus argus,in Florida?     

Donald C. Behringer  Mark J. Butler IV  William F. Herrnkind  John H. Hunt  Charles A. Acosta  William C. Sharp 《新西兰海洋与淡水研究杂志》2013,47(1):327-337

Caribbean spiny lobster (Panulirus argus) settle preferentially in macroalgal‐covered hard‐bottom habitat, but seagrass is more prevalent in Florida (United States) and the Caribbean, so even low settlement of lobsters within seagrass could contribute substantially to recruitment if post‐settlement survival and growth were high. We tested the role of seagrass and hard‐bottom habitats for P. argus recruitment in three ways. We first explored possible density‐dependent regulation of early benthic juvenile lobster survival within cages deployed in seagrass and hard‐bottom habitats. Second, we compared settlement and survival of P. argus in both habitats, by comparing the recovery of microwire‐tagged early benthic juveniles from patches of seagrass and hard‐bottom. Finally, we assessed the relative abundance of juvenile lobsters in each habitat by deploying artificial structures in seagrass sites and compared these data with data from similar deployments of artificial structures in hard‐bottom habitat in other years. More early benthic juvenile lobsters were recovered from cages placed in hard‐bottom than in seagrass, but mortality of the early benthic life stage was high in both habitats. In regional surveys, the mean number of lobsters recovered from artificial shelters deployed within seagrass was lower than in any year that we sampled hard‐bottom, indicating that fewer lobsters reside naturally in seagrass, particularly large juveniles >40 mm carapace length. The greater abundance (and likely survival) of juvenile P. argus that we observed in hard‐bottom habitat as opposed to seagrass, combined with previous studies demonstrating that postlarval P. argus are attracted to, settle in, and metamorphose more quickly in red macroalgae, confirm that macroalgae‐dominated hard‐bottom habitat appears to be the preferred and more optimal nursery for Caribbean spiny lobster.  相似文献   

The gastropod genus Thalassocyon Barnard, 1960     

A. G. Beu 《新西兰海洋与淡水研究杂志》2013,47(3):445-452

The tonnacean genus Thalassocyon Barnard, 1960 contains only two species, T. bonus Barnard, 1960 from deep water off South Africa and T. mi Dell, 1967 from deep water off northern New Zealand. The genus is removed from the Cymatiidae and placed in the Ficidae on the basis of shell morphology, the reduced periostracum and the details of the radula.  相似文献   

Growth rates of five species of surf clams on a southern North Island beach,New Zealand     

H. John Cranfield  Keith P. Michael 《新西兰海洋与淡水研究杂志》2013,47(5):909-924

Abstract

Growth rates of five species of surf clam were estimated on the Kapiti Coast, southern North Island, New Zealand. Length‐frequencies of sequential population samples were analysed by the computer program, MULTIFAN. Incremental growth of marked individuals was analysed by the computer program, GROTAG. The von Bertalanffy growth parameters k and L ₈ estimated by MULTIFAN for Spisula aequilatera (Deshayes in Reeve, 1854) were 0.80 yr^?1 and 52.1 mm; for Mactra murchisoni Deshayes in Reeve, 1854 were 0.60 yr^?1 and 72.3 mm; and for M. discors Gray, 1837 were 0.35 yr^?1 and 60.1 mm. MULTIFAN could not model growth of Paphies donacina (Spengler, 1793) and Dosinia anus (Philippi, 1848) from the population samples. The growth parameters estimated by GROTAG for D. anus were 0.53 yr^?1 and 53.0 mm and for M. murchisoni 1.84 yr^?1 and 72.4 mm. The growth rates of P. donacina, S. aequilatera, and M. discors were estimated for the size range of their incremental growth data and the estimates are usable for this limited size range only. Growth rates of each species varied with depth in the surf zone in the same way in the North and the South Island. The growth rate of two species was faster in the South Island and asymptotic size of all species was greater in the South Island.  相似文献   

Coral recruitment and potential recovery of eutrophied and blast fishing impacted reefs in Spermonde Archipelago,Indonesia     

Yvonne Sawall  Jamaluddin Jompa  Magdalena Litaay  Andi Maddusila  Claudio Richter 《Marine pollution bulletin》2013

Coral recruitment was assessed in highly diverse and economically important Spermonde Archipelago, a reef system subjected to land-based sources of siltation/pollution and destructive fishing, over a period of 2 years. Recruitment on settlement tiles reached up to 705 spat m⁻² yr⁻¹ and was strongest in the dry season (July–October), except off-shore, where larvae settled earlier. Pocilloporidae dominated near-shore, while a more diverse community of Acroporidae, Poritidae and others settled in the less polluted mid-shelf and off-shore reefs. Non-coral fouling community appeared to hardly influence initial coral settlement on the tiles, although, this does not necessarily infer low coral post-settlement mortality, which may be enhanced at the near- and off-shore reefs as indicated by increased abundances of potential space competitors on natural substrate. Blast fishing showed no local reduction in coral recruitment and live hard coral cover increased in oligotrophic reefs, indicating potential for coral recovery, if managed effectively.  相似文献   

A dynamic riparian forest structure model for predicting large wood inputs to meandering rivers     

John C. Stella  Li Kui  Gregory H. Golet  Frank Poulsen 《地球表面变化过程与地形》2021,46(15):3175-3193

Fluvial processes strongly influence riparian forests through rapid and predictable shifts in dominant species, tree density and size that occur in the decades following large floods. Modelling riparian forest characteristics based on the age and evolution of floodplains is useful in predicting ecosystem functions that depend on the size and density of trees, including large wood delivered to river channels, forest biomass and habitat quality. We developed a dynamic model of riparian forest structure that predicts changes in tree size and density using floodplain age derived from air photos and historical maps. Using field data and a riparian forest chronosequence for the 160-km middle reach of the Sacramento River (California, USA), we fit Weibull diameter distributions with time-varying parameters to the empirical data. Species were stratified into early and late successional groups, each with time-varying functions of tree density and diameter distributions. From these, we modelled how the number and size of trees in a stand changed throughout forest succession, and evaluated the goodness-of-fit of model predictions. Model outputs for the early successional group, composed primarily of cottonwoods and willows, accounted for most of the stand basal area and large trees >10 cm DBH for the first 50 years. Post-pioneer species with slower growth had initially low densities that increased slowly from the time of floodplain creation. Within the first 100 years, early successional trees contributed the most large wood that could influence fluvial processes, carbon storage, and instream habitat. We applied the model to evaluate the potential large wood inputs to the middle Sacramento River under a range of historical bank migration rates. Going forward, this modelling approach can be used to predict how riparian forest structure and other ecosystem benefits such as carbon sequestration and habitat quality respond to different river management and restoration actions.  相似文献   

Growth of juvenile tarpon in Puerto Rican Estuaries     

Zerbi  A.; Aliaume  C.; Joyeux  J.-C. 《ICES Journal of Marine Science》2001,58(1):87-95

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Estimation of the size of molluscan larval settlement using the death assemblage     

E.N. Powell  H. Cummins  R.J. Stanton  G. Staff 《Estuarine, Coastal and Shelf Science》1984,18(4):367-384

The death assemblage is an important source of information about temporal variability in community composition. The living community and the short-term death assemblage have been studied at a sandy-bottom station in the Laguna Madre, Texas. Abundance peaks of living species are usually followed by long-term abundance increases of the same species in the death assemblage. This phenomenon provides a tool for investigating between-sampling-occasion events in the preservable component of the living community. Given a six-week sampling regimen, approximately 90% of all individuals settle, live and die during the period between consecutive sampling occasions and are not collected alive. Thus, larval settlements are consistently underestimated by about 90% from data on the living community. Comparisons of year-to-year variability in settlement and survivorship of settled individuals in the youngest age classes may be considerably in error. Better estimations of actual settlement and survivorship can be made from the death assemblage provided that the rate of taphonomic loss can be quantified. The rate of taphonomic loss can be expressed as the species' half-life, the time required for the destruction of 50% of the individuals that were added to the death assemblage following settlement. Half-lives for the smallest size classes in the death assemblage at this site are about 100 days.  相似文献   

Geo-questionnaires in urban planning: recruitment methods,participant engagement,and data quality     

Michał Czepkiewicz  Piotr Jankowski  Marek Młodkowski 《制图学和地理信息科学》2017,44(6):551-567

ABSTRACT

Recent focus on sustainable urban development and livability has increased the demand for new data sourcing techniques to capture experiences and preferences of urban dwellers. At the same time, developments of geospatial technologies and social media have enabled new types of user-generated geographic information and spatially explicit online communication. As a result, new public participation GIS methods for engaging large groups of individuals have emerged. One such method is geo-questionnaire, an online questionnaire with mapping capabilities, which has been used to elicit geographic data in variety of topics and geographical contexts. This article presents two recent cases, in which geo-questionnaires have been used in Polish cities to obtain public input on quality of life and development preferences in local land use planning. The article evaluates participant recruitment methods focusing on sample representativeness, participant engagement, and data quality. Recruitment via social media was found to increase bias towards younger population. Paper questionnaires used along the online version provided for better representation of target population’s age structure, but did not reduce bias related to educational attainment. We discuss how these issues relate to data usability and generalizability in the context of digital divide, and suggest directions for future research.  相似文献   

Artemia parthenogenetica in Lake Hayward, Western Australia. I. Interrupted recruitment into adult stages in response to seasonal limnology     

Alan Savage  Brenton Knott 《International Journal of Salt Lake Research》1998,7(1):1-12

Lake Hayward, Western Australia, is a pristine, monomictic coastal lake with a residual brine (depth=1.5 m) of 200 gL⁻¹: stratification in winter (May to October) followed the input of ground water and rain. The epilimnion had temperature ranges of 10–30°C, and salinity from 65–110 g L⁻¹. Maximum depth in winter was 2.4 m. The population structure of the brine shrimpArtemia parthenogenetica, the dominant metazoan grazer in Lake Hayward, was studied from September, 1989, to February, 1991. The L. Hayward population ofA. parthenogenetica is predominantly ovoviviparous with little recruitment into the adult population. Cyst production occurs in summer, and there was evidence for recruitment from cyst hatching in the winters of 1989 and 1990. Nauplii were continuously present throughout the study period. Nevertheless, recruitment through to adult stages as defined by the presence of gravid females occurred only twice: in October–December, 1989 and in December, 1990. Based on limited observations of long-term survival of laboratory cultures, we believe that the major mechanism controlling nauplius survival and recruitment ofArtemia in Lake Hayward is food quality and quantity.  相似文献   

Coral Recruitment and Regeneration on a Maldivian Reef Four Years after the Coral Bleaching Event of 1998. Part 2: 2001–2002     

Karen Loch  Wolfgang Loch  Helmut Schuhmacher  & Wolf R. See 《Marine Ecology》2004,25(2):145-154

Abstract.  This paper is the follow-up study to a quantitative inventory of stony corals on a Maldivian reef after the bleaching event of 1998 [Loch, K., W. Loch, H. Schuhmacher & W. R. See, 2002; P.S.Z.N.: Marine Ecology, 23 (3): 219–236] covering the years 2001 and 2002, thereby extending the observation period from 1999 to 2002. Data collection was performed as previously in transects on the reef flat, Acropora tables at the reef rim, Porites lobata blocks and one Diploastrea heliopora colony. While between 2000 and 2001 the transects showed a noticeable increase of living scleractinian colonies of 6.1 per m² of reef surface per year, this had slowed to 0.7 per m² per year by 2002. Likewise, the colonisation of dead Acropora tables had changed from a yearly increase of 14.4 colonies per m² of table surface between 2000 and 2001 to a decrease of 9.4 between 2001 and 2002. The main constituent of the regeneration in transects as well as on Acropora tables was Pavona (Agariciidae), whereas Pocilloporidae and Acroporidae were almost completely missing. A new immigrant was Tubastraea micranthus . Continuous growth of regenerates on Porites presented a columnar form, and the growth rate of D. heliopora was reduced between 2001 and 2002. The influence on reef ecology in terms of coral substrate, species differentiation, growth rate changes, interaction with other organisms and the overall prospect of the reef development on a longer timescale is outlined.  相似文献