Mangrove Zone Research Articles

Variation in the Colonization of Artificial Substrates by Mangrove Root Fouling Species of the Port Royal Mangrove Lagoons in the Eutrophic Kingston Harbour, Jamaica

The aim of this study was to investigate temporal changes in mangrove root fouling species settled on artificial substrates in the mangrove zone of the Port Royal lagoons and to determine the effect of stress as part of a larger project to determine appropriate indicators of eutrophication in mangrove lagoons. Five Perspex? panels were suspended in the prop root zone at five contrasting stations within the Port Royal mangroves and the fouling organisms were monitored fortnightly using underwater digital photography. Nine taxonomic categories of epibionts were recorded of which the most prevalent group was the ascidians. Barnacles and hydroids were initially found to have established on the artificial substrates at all stations but were quickly replaced by ascidians and bryozoans at most. Species composition was similar between all stations by the end of the study, however, the dominant taxa were different. Sheltered lagoons like Fort Rocky lagoon (north and south) had a clear dominance of non-shelled species (ascidians and polychaetes) by the end of the study, while molluscs- bivalves and barnacles dominated Hurricane Refuge lagoon. This station, deemed to be experiencing greatest stress due to exposure to the eutrophic Kingston Harbour, also had the greatest proportion of shelled taxa represented in the epibiont biomass at the end of the study. Differences in biomass and species composition of root fouling species can therefore be used to indicate water quality in the mangrove lagoons.

Sediment Bioturbation Potential of Uca rapax and Uca uruguayensis as a Result of Their Feeding Activity

Bioturbation of mangrove sediments by Uca uruguayensis (Nobili, 1901) and U. rapax (Smith, 1870) was compared based on the grain-size composition and organic content in surface sediment around the burrow and feeding pellets in two mangrove zones of the Sao Vicente Estuary, state of Sao Paulo, Brazil. For each species, 25 burrows with active crabs were selected. All pellets within a 15-cm radius of each burrow were carefully collected; samples of substrate were taken; and the crab occupant was excavated, sexed, and measured for carapace width (CW). The number of spoon-tipped setae on the second maxilliped of each species was estimated; U. uruguayensis showed more of these setae than U. rapax. For both species, the sediment post-processed by feeding activity (feeding pellets) showed a similar increase of coarser fractions and a smaller organic content. However, U. uruguayensis was more efficient in removing organic matter (88.1%) from the sediment than U. rapax (37.5%). These results suggest that different numbers of spoon-tipped setae on the second maxillipeds of the fiddler crabs do not affect the potential for grain-size selection, but result in differing abilities to remove organic matter from the sediment.

ANALISIS TATA RUANG (ZONASI) PENGEMBANGAN EKOWISATA DI KAWASAN TAMAN NASIONAL BALURAN JAWA TIMUR

Research on potential ecotourism development at Baluran National Park which consists more than 25.000 Hectares area and coast line about 42 km long has been conducted from June to September 2003 in the local communities area around Baluran National Park and 5 ecosystems type such as mangrove forest, lowland tropical forest, deciduous forest, evergreen forest, and grassland. The objectives of this study were to definited the zonation for ecotourism. For these, research was initiated to inventory ecotourism supply such are biophysic attractions, socio culture local people attractions, tour object around Baluran National Park and facilities attractions. In order to obtain data and information for ecotourism demand of tourist and local people characteristic included activity, interest and opinion data were collected through questionnaires and open-ended interviews. The collected data were analyzed by using zonation analysis for ecotorism landscape. Based on the zonation analysis revealed that at Baluran National park obtained 3 zonation that could further develop for ecotourism: (1) mangrove and coral reef ecotourism zonation, (2) savana and forest ecotourism zonation, (3) village ecotourism zonation. Kind of attraction for ecotourism on each zonation are biodiversity of flora and fauna, coral reef, etnobotany information and cultural local people activities.

Empirical tools for simulating salinity in the estuaries in Everglades National Park, Florida

Salinity in a shallow estuary is affected by upland freshwater inputs (surface runoff, stream/canal flows, groundwater), atmospheric processes (precipitation, evaporation), marine connectivity, and wind patterns. In Everglades National Park (ENP) in South Florida, the unique Everglades ecosystem exists as an interconnected system of fresh, brackish, and salt water marshes, mangroves, and open water. For this effort a coastal aquifer conceptual model of the Everglades hydrologic system was used with traditional correlation and regression hydrologic techniques to create a series of multiple linear regression (MLR) salinity models from observed hydrologic, marine, and weather data. The 37 ENP MLR salinity models cover most of the estuarine areas of ENP and produce daily salinity simulations that are capable of estimating 65–80% of the daily variability in salinity depending upon the model. The Root Mean Squared Error is typically about 2–4 salinity units, and there is little bias in the predictions. However, the absolute error of a model prediction in the nearshore embayments and the mangrove zone of Florida Bay may be relatively large for a particular daily simulation during the seasonal transitions. Comparisons show that the models group regionally by similar independent variables and salinity regimes. The MLR salinity models have approximately the same expected range of simulation accuracy and error as higher spatial resolution salinity models.

Phytolith assemblages of grasses from the Sunderbans, India and their implications for the reconstruction of deltaic environments

Grasses are among the most abundant, diverse and ecologically important group of plants; their number and diversity make them a significant part of the ecosystem. The characteristic presence of opaline silica in grasses makes them a valuable tool in environmental reconstruction over other groups of vascular plants. Fifty grass taxa belonging to four different subfamilies viz., Panicoideae, Chloridoideae, Ehrhartoideae and Bambusoideae of family Poaceae were collected for phytolith analysis from different eco-vegetational zones viz., swampy mangrove or intertidal mangrove zone, tidal mangrove zone, true mangrove decline zone, zone for colonization of non-littoral species and xerophytic non-mangrove species and dry evergreen forest zone along the coastal regions of the Indian part of the Sunderbans. Predominant phytolith assemblages recovered from these grass taxa might help in discriminating different deltaic sub-environments. It was observed that the dominant grasses of the true mangrove decline zone and the zone for colonization of non-littoral species produced abundant lobate and cross morphotypes. On the other hand, a predominance of flat towers followed by short saddles, three-horned towers, two-horned towers and keeled rondels were noticed in the members of Chloridoideae growing in the xerophytic non-mangrove and dry-evergreen forest zone along riverbanks. In contrast, chloridoid members adapted to the tidal mangrove ridge forest produced spool/horned towers in the highest frequencies followed by ellipsoid rondels and two-horned towers. Grasses exclusively growing on salt marshes of the swampy intertidal mangrove zone showed a dominance of ellipsoid rondel morphotypes followed by flat tower and two-horned towers. The observations were corroborated by the results of principal components analysis (PCA) on modern phytolith data. The result may serve as a basis for the future interpretation of depositional environments of fossil phytolith assemblages recovered from deltaic regions along a salinity gradient.

Impacts of Spartina alterniflora invasion on abundance and composition of ammonia oxidizers in estuarine sediment

Spartina alterniflora widely invades coastal wetland in China and might change nitrification in sediment. Both ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) are involved in nitrification in this environment. The objective of this study was to examine the effect of S. alterniflora invasion on abundance and composition of AOA and AOB. The abundance and composition of AOA, AOB, and total bacteria in the sediments from S. alterniflora-invaded native mangrove vegetated and unvegetated zones at two depths of 0–5 cm (O) and 5–20 cm (R) were investigated using quantitative real-time polymerase chain reaction and denaturing gradient gel electrophoresis. Relationships were also determined between sediment properties and the AOB and AOA population sizes. Compared with native mangrove vegetated zone, the archaeal amoA gene abundance was reduced by 11.3-fold (O) and 46.1-fold (R), but the bacterial amoA gene abundance was increased by 9.8-fold (O) and 1.8-fold (R), respectively, in the S. alterniflora-invaded zone. The AOA abundance was always higher than AOB, especially in the native mangrove zone. Both AOA and AOB population sizes in the upper layer (O) were bigger than those in the deeper layer (R). Little difference was found in the AOB community composition among different zones, while diversity of AOA community was increased by the presence of S. alterniflora. This study demonstrated that the S. alterniflora invasion affects the abundance of both AOA and AOB, but only affects the community composition of AOA in the tidal sediments.

A new species of Parasesarma (Crustacea: Brachyura: Sesarmidae) from the mangroves of Western Australia

A new species of intertidal sesarmid crab, Parasesarma hartogi, is described from the upper mangrove zone in Shark Bay, Western Australia. It differs from its four closest relatives in the P. plictatum species-complex by being broader between the epibranchial angles than between the exorbital angles; showing differences in the number and form of the dorsal dactylar tubercles of the male cheliped, a relatively broader gape between the fingers of the adult male chelae, proportions and shape of the male abdomen, and shape of the male first gonopod.

The fauna of mangroves

Introduction: The fauna of mangroves basically reflects the convergence of two types of habitat, a sheltered marine muddy intertidal habitat and a terrestrial forest. In temperate areas, mangroves form fairly open, one layered forests; in tropical areas they may be open or closed, often multilayered with distinct zonation. The terrestrial fauna is to a large extent, restricted to the forest canopy and the marine fauna to the substrate and lower levels of the forest, so a horizontal partitioning of the two dominant kinds of fauna occurs. A third component, a freshwater fauna may be present along the margins of the mangroves in the upper reaches of the estuary. Within the two major faunal components, subdivision occur. For the terrestrial fauna, this may be related to the zonation of the mangroves themselves. For example certain species of insects are restricted to particular mangrove trees, e.g. the butterfly Hypochrysops epicurus is restricted to Avicennia marina. The terrestrial fauna may also be affected by the type of vegetation adjacent, this may be Malaleuca/eucalypt forest, Juncus sedgelands, Malaleuca swamps; rainforests or bare salt plains. In some cases, mangroves may provide the only refuge for terrestrial species, in others they serve as a corridor linking adjacent habitats.

Blood-Feeding Behavior of <I>Anopheles gambiae</I> and <I>Anopheles melas</I> in Ghana, Western Africa

Anopheles gambiae is the predominant malaria vector species in Ghana, western Africa, with a strong local presence of Anopheles melas Theobald along the southern coast. We studied the biting behavior of these two species of the Anopheles gambiae complex inland and at the coast in Ghana, with special attention to the local peoples' preference for outdoor sleeping. We collected mosquitoes at two sites in 2007, representing the moist semideciduous forest zone and the strand and mangrove zone, and the sampling was repeated in the dry and rainy seasons. Sampled mosquitoes were examined for species, parity and size (wing length), and we identified the hosts of their bloodmeals. We interviewed 288 of the village people to determine where and when they slept outdoors. Our study confirmed that An. gambiae is the only species of the An. gambiae complex in the Ashanti region and revealed that An. melas is highly dominant on the western coast of Ghana. Both species showed high human blood rates in indoor resting mosquito samples. More people sleep outside on the coast than inland. An. melas demonstrated high exophily. An. gambiae bit people more frequently indoors and did so more often during the dry season than in the rainy season. We suggest that the degree of exophily in An. melas may be affected by humidity and the availability of human as well as by the mosquitoes' innate habits.

Australian Saltmarsh Ecology

Australia, including its territorial islands, is surrounded by almost 60 000 km of coastline (Geoscience Australia, http://www.ga.gov.au/education/) and, according to Saintilan, coastal saltmarshes occupy some 16 000 km2. Saltmarshes provide valuable ecosystem services and are generally recognized as among the most productive ecosystems on Earth. This is considered to be ecologically important because excess detrital matter exported to marine waters sustains food webs, including important fisheries (i.e., Odum?s [1980] ?outwelling hypothesis?). Although physically and biologically similar to saltmarshes elsewhere, Australian coastal saltmarshes have certain unique characteristics (e.g., the tidal zonation of marsh and mangroves and levels of productivity) that natural resource managers need to be aware of. Perhaps more so than elsewhere, the great majority of the Australian population lives along or near the coast. Consequently, Australian saltmarsh environments have been subject to significant human-driven change since European settlement. In spite of these compelling facts, Australian publications remain under-represented relative to the extent of saltmarsh on the continent. Australian Saltmarsh Ecology does much to correct this situation.

Surface Elevation Change and Susceptibility of Different Mangrove Zones to Sea-Level Rise on Pacific High Islands of Micronesia

Mangroves on Pacific high islands offer a number of important ecosystem services to both natural ecological communities and human societies. High islands are subjected to constant erosion over geologic time, which establishes an important source of terrigeneous sediment for nearby marine communities. Many of these sediments are deposited in mangrove forests and offer mangroves a potentially important means for adjusting surface elevation with rising sea level. In this study, we investigated sedimentation and elevation dynamics of mangrove forests in three hydrogeomorphic settings on the islands of Kosrae and Pohnpei, Federated States of Micronesia (FSM). Surface accretion rates ranged from 2.9 to 20.8 mm y−1, and are high for naturally occurring mangroves. Although mangrove forests in Micronesian high islands appear to have a strong capacity to offset elevation losses by way of sedimentation, elevation change over 6½ years ranged from −3.2 to 4.1 mm y−1, depending on the location. Mangrove surface elevation change also varied by hydrogeomorphic setting and river, and suggested differential, and not uniformly bleak, susceptibilities among Pacific high island mangroves to sea-level rise. Fringe, riverine, and interior settings registered elevation changes of −1.30, 0.46, and 1.56 mm y−1, respectively, with the greatest elevation deficit (−3.2 mm y−1) from a fringe zone on Pohnpei and the highest rate of elevation gain (4.1 mm y−1) from an interior zone on Kosrae. Relative to sea-level rise estimates for FSM (0.8–1.8 mm y−1) and assuming a consistent linear trend in these estimates, soil elevations in mangroves on Kosrae and Pohnpei are experiencing between an annual deficit of 4.95 mm and an annual surplus of 3.28 mm. Although natural disturbances are important in mediating elevation gain in some situations, constant allochthonous sediment deposition probably matters most on these Pacific high islands, and is especially helpful in certain hydrogeomorphic zones. Fringe mangrove forests are most susceptible to sea-level rise, such that protection of these outer zones from anthropogenic disturbances (for example, harvesting) may slow the rate at which these zones convert to open water.

Comportamento geoquímico de metais em sedimentos de manguezal da Baía de Camamu-Bahia

This inquiry encloses the sediments and mangroves of the Camamu Bay, Bahia, Brazil. 13 stations of sampling had been selected in which sediments, water and leaves were collected. Of these stations, 5 are located in mining zones and 8, in the estuary of the rivers that flow down the bay. The samples had been separate by grain size, mineralogical characteristics, metals (Pb, Zn, Cr, Cu, Cd, Ba, Mn, Fe and Al), organic substances and nutrients. The results of the metals have evidenced differentiated geochemical behaviors for each one of the mangrove zones (compartment of the islands and around the Camamu Bay). The amounts of Pb, Zn and Cu, had been raised in the islands compartment, while Mn, Cr, Al and Fe, presented higher concentration around the Bay. In relation to the dynamics of metal partition in the zones of mining of the interior islands, it was observed a preoccupying increase of Pb, Zn, Mn and Ba.

A preliminary assessment of NigeriaSat-1 for sustainable mangrove forest monitoring

Mangroves constitute an area of great ecological importance and regular assessment and monitoring of this ecosystem is an integral part of environmental management plan. The difficulty of access for ground survey has often limited the frequency of assessment of mangroves and remote sensing methods therefore provide a veritable means of assessment. However, accessibility to remotely sensed data as well as the cost have been major constraints for mangrove assessment in the developing countries. The launching of small satellites by some developing countries may therefore provide a solution to this problem. This paper is an attempt to evaluate the capability of NigeriaSat-1 which is one of the Disaster Management Constellation (DMC) small satellites for generation of baseline information on cover types and areal extents within the mangrove zone in Nigeria. This is important since cover information is always the first step for conservation and management. The study shows that the results obtained from NigeriaSat-1 have comparable accuracy with ASTER and Landsat ETM+. The findings documented in this paper could serve as a springboard for organized wetland management in Nigeria in particular and West Africa sub-region in general.

Gut microbiota of crabs from the Vellar estuary, southeast coast of India

Animals in the aquatic environment carry a particular bacterial flora that is a reflection of their environment. In the present study the level of total heterotrophic bacterial (THB) populations observed in the gut of crabs simply reflected the THB in the water and sediment of the environments from which the crabs were collected. Crabs were collected from the different areas, i.e. neritic, mangrove and oyster zones, of the Vellar estuarine environment of the southeast coast of India. THB populations were high in the water and sediment in the mangrove and neritic zones. Among the three stations, less bacterial populations were observed in the water, sediment and the gut of the crabs in the oyster zones due to the constant disturbance of wave action from the estuarine mouth region. Bacteria belonging to the genera Pseudomonas and Vibrio were found to be higher in all the three different stations. In the mangrove region, Bacillus was the dominant genus in sediment samples. Key words: Gut microbiota, crabs, neritic zone, oyster zone, mangrove zone

Forest structure of arid zone mangroves in relation to their physical and chemical environment in the western Gulf of Kachchh, Gujarat, Northwest coast of India

To understand natural and anthropic control of mangrove vegetation in the Gulf of Kachchh, a study was undertaken of its vegetation structure. Over 2 years (1999–2000) at three sites, mangrove vegetation was studied, including tree density, tree height, tree girth at breast height (GBH), canopy index, regeneration class and recruitment class, together with physico-chemical characteristics of water and sediment and the textural aspects of sediments. Reflecting the hot, arid hinterland of Gujarat, ambient temperatures and salinities are high in this macrotidal estuary, decreasing somewhat during the monsoon. The littoral soil supporting the mangrove is abundant in silty loam, silty clay and slity clay loam. The density of mature trees (Mangrove plants of GBH > 25 cm) ranged from 2088/ha to 3011/ha, the height of the trees ranged from 1.42 m to 9 m and the maximum mean GBH at all three sites was 33 cm, and the mean canopy indices ranged between 4.77 m2 and 10.45 m2. The maximum density of regeneration stages was 100,800/ha while that of recruitment stages was only 3,040/ha. While quite severely impacted by anthropic exploitation at one site, the mangrove ecosystem of Gulf of Kachchh was found to be mainly healthy and supporting associated organisms. The ecological and social role of the mangrove, and the potential for its future conservation are briefly discussed in the light of current legislation.

Characterization of phosphorus fractions in the sediments of a tropical intertidal mangrove ecosystem

Solid phases of phosphorus fractions in the surface and core sediments were studied to understand the biogeochemical cycling and bioavailability of phosphorus in the Pichavaram intertidal mangrove sediments of India. Total P in surface and core sediments ranged between 451–552 and 459–736 μg g−1 respectively and Fe bound P was the dominant fraction. Low levels of Fe bound P in the mangrove zone than the two estuarine zones may be because of high salinity inhibition of phosphate adsorption onto the Fe-oxides/hydroxides. Post-depositional reorganization of P was observed in surface sediments, converting organic P and Fe bound P into the authigenic P. High levels of organic P in the mangrove zone is primarily due to intensive cycling and degradation of organic matter and adsorption of phosphate on the organic molecules. The burial rates and regeneration efficiency of P in the intertidal mangrove ecosystem ranged from 5.41 to 7.27 μmol P cm−2 year−1 and 0.122 to 0.233 μmol P cm−2 year−1, respectively. High burial efficiency (≈99%) of P proves the earlier observation of limiting nature of P for the biological productivity. Further, bioavailable P (exchangeable P + Fe bound P + organic P) constituted a considerable proportion of sedimentary P pool of which an average accounted for 55 and 50% in surface and core sediments respectively. The results indicate that significant amount of P is locked in sediments in the form of authigenic P and detrital P which makes P as a limiting nutrient for the biological productivity.

Organic matter characterization in a tropical estuarine-mangrove ecosystem of India: Preliminary assessment by using stable isotopes and lignin phenols

In order to characterize the sources and fate of organic matter (OM) in the Pichavaram estuarine-mangrove ecosystem (east coast of India), stable isotope (δ 13C and δ 15N) ratios and molecular lignin analyses were conducted in plant litter, benthic algae, sediment, particulate matter and in a variety of benthic invertebrate species. The δ 13C signature of plant litter ranges from −29.75‰ to −27.64‰ suggesting that mangrove trees follow the C 3 photosynthetic pathway. Sedimentary δ 13C signature (−28.92‰ to −25.34‰) demonstrates the greater influence of plant litter organic matter on sedimentary organic matter. Suspended particulate organic pool was influenced by terrestrial source and also seems to be influenced by the marine phytoplankton. Enriched signature of δ 15N in surface sediments (4.66–8.01‰; avg. 6.69‰) suggesting the influence of anthropogenic nitrogen from agricultural fields and human settlements. Spatial chemical variability in availability of nitrogen and plant associated microbial interactions demonstrate variability in δ 15N signature in mangrove plant litter. Two (lower and higher) trophic levels of invertebrates were identified with and observed >4‰ gradient in δ 13C signal between these two trophic groups. The observed δ 13C values suggest that the lower level invertebrates feed on phytoplankton and higher level organisms have a mixed source of diet, phytoplankton, sediment and particulate organic matter. Lignin phenol analyses explain that the benthic surface layer was almost free of lignin. The ratio between syringyl phenols to vanillyl phenols (S/V) is 1.14–1.32 (avg. 1.23) and cinnamyl phenols to vanillyl phenols (C/V) is 0.17–0.31 (avg. 0.24), demonstrate non-woody angiosperm tissues was the major sources of lignin to this ecosystem, while aldehyde to acid ratios (Ad/Al) describe diagenetic nature of sediment and is moderately to less degraded. A two-end-member mixing model indicate that the terrigenous OM was dominant in the estuarine zones, while in the mangrove zone terrigenous supply accounts for 60% and marine input accounts for 40%.

Fishery resources in arid zone mangroves in gulf of Kachchh, Gujarat, northwest coast of India

The finfish and shellfish resources were assessed quantitatively and qualitatively in regard to their abundance in creek waters at three sites within a period of two years, from January 1999 to December 2000, in the western mangrove areas of Kachchh. The catch rate varied from 0.69 to 6.99 kg•h^(-1). It was low during monsoon (July to October), which could be due to the freshwater-flow-induced salinity reduction in all the sites. Among 38 species recorded, 5 were shellfish and 33 were finfish. The spawning period of fishes was found to be during summer and early monsoon period (May to August). Surface water temperatures varied from 17℃ to 37℃. Sa-linity values varied from 34 to 44 and the pH ranged between 7 and 8.9. Variation in dissolved oxygen content was from 3.42 to 5.85 Ml•L^(-1). The high fishery densities in these semi arid mangrove creek areas were recorded during monsoon and early winter season.

Conservation of the false water rat (Xeromys myoides) depends on landscape complementation

Identification of habitat variables that are associated with patch occupancy can provide a solid foundation for conservation, especially when habitats and landscapes are affected by human activities. As a case study to investigate the importance of landscape complementation and habitat quality for conservation, we examined the habitat preferences of a vulnerable native rodent, the false water rat (Xeromys myoides Thomas). In this study, results from surveys for animal presence and recording of habitat attributes in localities in south-east Queensland showed that X. myoides prefers a habitat with a wide mangrove zone of short mangroves and a high percentage of relatively tall vegetation cover in the sedge/saltmarsh zone. The absence of X. myoides from areas of likely habitat at a large scale can be attributed, at least in part, to the local habitat variables that overrode predictions based at a large scale. The findings suggest that availability of suitable habitat is a factor limiting the distribution and abundance of X. myoides. It is clear that landscape complementation influences patch occupancy and should be an essential consideration for conservation programs.

Degradasi Hutan Bakau Akibat Pengambilan Kayu Bakar oleh Indutri Kecil Gula Kelapa di Cilacap

A study on degradations mangrove forest due to firewood exploitation by coconut palm sugar home industry in Cilacap. Information on social economic aspect and respons of coconut palm sugar home industry to using fuel substitutions were collected by using a questioner. The potential of mangrove as a firewood source was estimated by quadrat method. The study has been carried out on dry and rainy season. The wood production of available 8000 ha of mangrove from Cilacap primarily Rhizophora apiculata Linn and Rhizophora mucronata Lamk were 3.249.920 m³. The results showed that the declining of mangrove was about 19,250 m² in dry season and 26,551 m² in rainy season, this was correlated with the amount of nira to be processed that was 0,782 m³ in dry season and 1,079 m³ in rainy season. Deforestation of mangrove forest due to change of mangrove zonation. Rhizophora apiculata Linn and Rhizophora mucronata Lamk will be domination Nypa fruticans that is shown superficiality to continent form.