6,606 research outputs found
The ecological basis of fishery yield of the Puerto Rico-Virgin Islands Insular Shelf: 1987 Assessment
A literature review was conducted to locate information on the flow of energy from primary producers to the fishery stocks of the Puerto Rican-Virgin Islands insular shelf. This report uses site-specific information to describe the major ecological subsystems, or habitats, of the region, to
identify the more common species and the subsystems in which they occur, to quantify productivity and biomass, and to outline trophic relationships. Discussions on each topic and subsystem vary in substance and detail, being limited by the availability and accessibility of information. (PDF contains 189 pages)
Seven distinct subsystems are described: mangrove estuary, seagrass bed, coral reef, algal plain, sand/mud bottom, shelf break, and overlying pelagic. Over 50 tables provide lists of species found in each habitat on various surveys dating back to 1956. Estimates of density, relative abundance, and productivity are provided when possible.
We evaluated whether sufficient information exists to support an analysis of the energy basis of fishery production in the area, beginning with the design and development of an ecosystem model. Data needs in three categories - species lists, biomass, and trophic relations - were examined for each subsystem and for each of three species groups - primary producers, invertebrates, and fish.
We concluded that adequate data, sufficient for modeling purposes, are available in 16 (25%) of 64 categories; limited data, those requiring greater extrapolation, are available in 35 (55%) categories; and no data are available in 13 (20%) categories. The best-studied subsystems are seagrass beds and coral reefs, with at least limited data in all categories. Invertebrates, the intermediate link in the food web between primary producers and fishes, are the least quantified group in the region. Primary production and fishes, however, are relatively well-studied, providing sufficient data to support an ecosystem-level analysis and to initiate a modeling effort
Grenada Carriacou Petite Martinique
The Eastern Caribbean Seascape is an arc of islands linked through diverse coral reef ecosystems, oceanic currents, migratory pathways and a rich cultural heritage. The Eastern Caribbean Coral Reef Report Cards are a series of individual reports for the6 participating countries and provide an easy-to-understand summary of the state of the region's marine resources. The Report Cards collate data from 277 comparable coral reef surveys and map in detail 383 km2 of coral reefs, 19 km2 of mangrove, 286 km2 of seagrass, 44 designated and 50 proposed Marine Managed Areas (MMA). The Report Cards provide an initial baseline on the current state of the reef and identify gaps. Reporting this type of information will help track progress in protecting reefs and inform future monitoring and management. The vision is to produce report cards every 2 years and share data through the CaribNode regional spatial data platform. Future report cards will include key socioeconomic and management effectiveness information. Each Report Card includes information on:Key Habitats (location and extent of coral, mangrove, seagrass)Reef Health Index (a measure of the health of four key coral reef indicators)Marine Managed Areas (size and location of designated and proposed areas
A simple and cost-effective method for cable root detection and extension measurement in estuary wetland forests
This work presents the development of a low-cost method to measure the length cable roots of black mangrove (Avicennia germinans) trees to define the boundaries of central part of the anchoring root system (CPRS) without the need to fully expose root systems. The method was tested to locate and measure the length shallow woody root systems. An ultrasonic Doppler fetal monitor (UD) and a stock of steel rods (SR) were used to probe root locations without removing sediments from the surface, measure their length and estimate root-soil plate dimensions. The method was validated by comparing measurements with root lengths taken through direct measurement of excavated cable roots and from root-soil plate radii (exposed root-soil material when a tree tips over) of five up-rooted trees with stem diameters (D130) ranging between 10 and 50 cm. The mean CPRS radius estimated with the use of the Doppler was directly correlated with tree stem diameter and was not significantly different from the root-soil plate mean radius measured from up-rooted trees or from CPRS approximated by digging trenches. Our method proved to be effective and reliable in following cable roots for large amounts of trees of both black and white mangrove trees. In a period of 40 days of work, three people were capable of measuring 648 roots belonging to 81 trees, out of which 37% were found grafted to other tree roots. This simple method can be helpful in following shallow root systems with minimal impact and help map root connection networks of grafted trees
Ecosystem carbon 7 dioxide fluxes after disturbance in forests of North America
Disturbances are important for renewal of North American forests. Here we summarize more than 180 site years of eddy covariance measurements of carbon dioxide flux made at forest chronosequences in North America. The disturbances included stand-replacing fire (Alaska, Arizona, Manitoba, and Saskatchewan) and harvest (British Columbia, Florida, New Brunswick, Oregon, Quebec, Saskatchewan, and Wisconsin) events, insect infestations (gypsy moth, forest tent caterpillar, and mountain pine beetle), Hurricane Wilma, and silvicultural thinning (Arizona, California, and New Brunswick). Net ecosystem production (NEP) showed a carbon loss from all ecosystems following a stand-replacing disturbance, becoming a carbon sink by 20 years for all ecosystems and by 10 years for most. Maximum carbon losses following disturbance (g C m−2y−1) ranged from 1270 in Florida to 200 in boreal ecosystems. Similarly, for forests less than 100 years old, maximum uptake (g C m−2y−1) was 1180 in Florida mangroves and 210 in boreal ecosystems. More temperate forests had intermediate fluxes. Boreal ecosystems were relatively time invariant after 20 years, whereas western ecosystems tended to increase in carbon gain over time. This was driven mostly by gross photosynthetic production (GPP) because total ecosystem respiration (ER) and heterotrophic respiration were relatively invariant with age. GPP/ER was as low as 0.2 immediately following stand-replacing disturbance reaching a constant value of 1.2 after 20 years. NEP following insect defoliations and silvicultural thinning showed lesser changes than stand-replacing events, with decreases in the year of disturbance followed by rapid recovery. NEP decreased in a mangrove ecosystem following Hurricane Wilma because of a decrease in GPP and an increase in ER
Variations in water use by a mature mangrove of Avicennia germinans, French Guiana
In the tropical intertidal zones, little is known on water uptake by mangroves. Transpiration rates are generally measured at leaf level, but few studies exist on water use at tree or stand levels. The objective of this study was to measure sap flow in trees of different sizes to appreciate the range of variation in water use that may exist in a site dominated by 80% mature Avicennia germinans. The results showed that from the dry to the wet season the mean water use increased from 3.2 to 5.3 dm3 d−1 in small trees (DBH ∼ 13 cm), from 11.5 to 30.8 dm3 d−1 in medium trees (∼24 cm) and from 40.8 to 64.1 dm3 d−1 in large ones (∼45 cm). Sapwood remained active up to a depth of 8 cm with radial variations within the stem. Weak correlations were obtained with VPD and net radiation. This study confirmed that transpiration was larger under low levels of salinity. Water use at stand level (∼1900 living stems ha−1) was estimated to be in the range of 5.8 to 11.8 m3 ha−1 d−1 according to the season
Summary of Coral Cay Conservation's habitat mapping data from Utila, Honduras
IIThe coral reefs of Honduras are of vital national and international importance,both ecologically and economically, but are threatened because of rapid economicand population growth.? During work on Utila between 1999 and 2000 (the ?Bay Islands 2000? project),Coral Cay Conservation developed a programme of surveys, training andconservation education aimed at assessing the status of local reefs and improvingenvironmental awareness amongst neighbouring communities.? This summary report provides an overview of the habitat mapping data collectedby the Bay Islands 2000 project.? CASA provided software, hardware and skills, on a charitable basis to ensure thatthe data collected by CCC could be developed into a GIS, not only for mappingthe status of the coral reefs of Honduras, but also to provide analysis of the aerialextent of these reefs.? Data were collected within individual ?study areas?, to facilitate analysis at a rangeof spatial scales, and utilised the CCC standard baseline survey technique for therapid assessment of the characteristics of reef communities. The surveys,therefore, utilised a series of transects, perpendicular to the reef.? Baseline transects discriminated nine benthic and six geomorpholgical classeswhich indicates Utila has a high habitat diversity. Habitat diversity is importantsince the number of habitat types has been shown to be a good representation ofspecies biodiversity.? The nine benthic classes that were distinguished were all relatively coral poorbecause of a suite of relatively long-term local and regional factors, exacerbatedby the combination of Hurricane Mitch and coral bleaching in 1995 and 1998.? Damselfish were the most abundant reef associated fish recorded during baselinetransect surveys. Commercially important fish were less abundant that wouldnormally be expected in unfished systems.? A recurring pattern in the baseline transect data was the greater abundance anddiversity of fish in coral rich classes. However, although the link between fishabundance and coral cover was clear, not all species were necessarily mostabundant in the most coral rich areas.? Invertebrates were generally uncommon, partly because of fishing pressure, andthe abundances of many invertebrate taxa were correlated with coral cover.? A habitat map is presented within this report as an indication of the distribution ofhabitat types around Utila.? Using the map, estimates of areal extents of each benthic class and habitat type areinstructive. For example, there is only approximately 27 km2 of reefal habitatsaround Utila. Furthermore, the area supporting the most coral rich benthic classesis only approximately 4 km2 (15%). These statistics both highlight the damagecaused by the bleaching event and Hurricane Mitch and other anthropogenicimpacts and the need to conserve remaining coral rich areas.? If further reserves were to be created, it would be important to try to protect arange of reef and habitat types. For this reason, it appears that the Turtle HarbourWildlife Refuge is well placed since this areas includes a wide range of habitattypes. However, placement of reserves in Utila should favour relatively coral richhabitats over sand dominated areas.? This study led to six recommendations:Summary Utila habitat mapping reportIII? One or more agencies should collect additional ground-truthing data fromaround Utila to facilitate both classification of currently ?Unknown? polygonsand an accuracy assessment of the map.? Establish an integrated GIS and associated meta-database for Utila, includingdata from the Bay Islands 2000 project.? Examine the potential of using data collected by the Bay Islands 2000 projectas the basis of national habitat classification scheme and subsequent nationalhabitat map.? Continue to aim to establish one or more additional multiple use marineprotected areas around Utila, with an integrated monitoring programme tomeasure their efficacy, and strengthen the enforcement of regulations in theTurtle Harbour Wildlife Sanctuary. Establish regulations, and enforce existinglegislation, to minimise the detrimental effects of coastal development on reefhealth.? Additional marine reserves in Utila should integrate factors such as thepreference of many fish species for coral rich habitats and the protection ofareas incorporating a range of habitat types, including mangroves and seagrassbeds, in order to allow for nursery areas, ontogenetic shifts and species thatrely on non-coral rich habitats. The corollary of the preference of fish speciesfor coral rich habitats is to protect coral cover within the reserves.? The reef on the south coast of Utila appears to be a good candidate forprotection because it is relatively sheltered from storm and hurricane damage
Antibacterial activities of three species of mangrove leaves extract against Staphylococcus aureus and Escherichia coli
The increasing incidence of infections and drug resistance has led scientists to seek approaches towards medicinal plants that are potentially effective against many microorganisms. Therefore, this study was planned to assess the antibacterial activity of 3 mangrove species (Scyphipora hydrophylaceae C.F.Gaertn., Lumnitzera littorea (Jack) Voigt and Avicennia alba Blume) against Staphylococcus aureus and Escherichia coli bacteria. This study used the disc diffusion method to measure the diameter of inhibition at several concentrations of mangrove leaf ethanol extracts, namely 15%, 10%, 5%, 2.5%, 1.25% and 0.625% b/v as well as positive control cefadroxil for bacteria and DMSO as negative control. The test results showed that ethanol extracts of mangosteen leave Scyphipora hydrophylaceae C.F.Gaertn and Lumnitzera littorea (Jack) Voigt had a solid response to Escherichia coli bacteria and moderate potential against S. Aureus bacteria—no antibacterial activity against both test bacteria for Avicennia alba mangrove. This study concludes that Scyphipora hydrophylaceae C.F.Gaertn and Lumnitzera littorea (Jack) Voigt have potent antibacterial activity against Escherichia coli, but Avicennia alba has no antibacterial activity
A tackle box guide to: common saltwater fishes of southwest Florida
There are well over 150 species of fish caught by hook and line in local waters. The 86 species
included in this book were selected by the author and editors because they are the most frequently
encountered. For eachspecies, important informationabout distinguishing features, biology/habitat, and
fishing methods is provided. The often confusing common nicknames applied to each fish are noted,
as well as the fish's preferred common name. (56pp.
Assessing the Value of Krabi River Estuary Ramsar Site Conservation and Development
Krabi River Estuary, a ramsar site located in southern Thailand, is dominated by two major natural vegetation assemblages, i.e. mangrove forests and seagrass beds. According to the cluster development strategy, the cabinet has approved in principle to develop Krabi as the global marine tourism center and economic gateway of Asia. This study aimed to assess the economic value of the site, using market price and benefit transfer. The impact on economic activities with the 5% annual decline of mangrove forests was evaluated. The estimated annual use value of the site was 758/ha. The net present value of mangrove forests was 21.0 million or 2.3 million per year to be considered as an economically feasible project.Krabi River Estuary,ramsar site,wetland management,economic valuation,direct use values
Living with the Sea: Local Efforts Buffer Effects of Global Change
Living with the Sea examines the role of MMAs (Marine Managed Areas) in restoring and sustaining healthy oceans, particularly the importance of local management efforts. This document draws on MMA experiences worldwide by synthesizing results from over 25 natural science studies conducted over the past five years in 18 tropical countries in 48 MMAs. The analysis focuses on the role of MMAs in maintaining healthy oceans, showing that MMAs can be used to enhance fisheries outside their borders and safeguard threatened species. Conserving multiple habitats using MMAs can also protect diverse livelihoods and increase fisheries yields. Local protection of marine resources through the MMA process can provide strong local benefits to species, habitats, and people. Local protection buffers against global climate change impacts while maintaining the richness of marine life. Finally, MMAs benefit by using new scientific approaches and engaging citizen scientists
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