Structure Of Mangrove Vegetation Research Articles

Qualitative and Quantitative Characterization of Mangrove Vegetation Structure and Dynamics in a Peri-urban Setting of Douala (Cameroon): An Approach Using Air-Borne Imagery

Qualitative and quantitative characterization of mangrove vegetation structure and dynamics is required for assessment of coastal habitat vulnerability. Changes in mangrove forests around Douala, Cameroon, have been documented using aerial photography between 1974 and 2009. The distribution pattern of tree species was also assessed in 2009 following the point-centered quarter method (PCQM+) protocol. Pristine mangroves observed in 1974 had been disturbed markedly in 2003 and 2009. Some of the pre-existing mangroves were entirely replaced by settlements, road, and crops (maize, bean, banana, oil palm, green vegetables, and sugar cane plantations). From 1974 to 2003, 39.86 % of mangrove forests have disappeared; the net loss of 22.10 % occurred between 2003 and 2009 alone. Mangrove forest area had decreased 53.16 % around Douala over a 35-year period from 1974 to 2009 concurrent with a substantial increase of settlements (60 %), roads (233.33 %), agriculture areas (16 %), non-mangrove areas (193.33 %), and open water (152.94 %). Field survey showed that almost one third of the quadrants in the remaining mangrove forest were empty. The disrupted mangrove forest has an overall mean height, absolute density, and basal area of 19.80 m, 158 trees ha−1, and 110.44 m2 ha−1, respectively. In comparison with scientific literature on mangrove degradation, this puts the mangroves around Douala at the top of the “peri-urban mangrove degradation” list. In addition, beyond listing of mangrove plants on the Red List of Threatened Species which will seldom lead to widely distributed species being listed, we call for the creation of a Red List of Locally Threatened Ecosystems, which in contrast is likely to list mangroves as an ecosystem under critical risk of (local) extinction in many countries around the globe, in particular, peri-urban sites.

Air temperature and canopy cover of impacted and conserved mangrove ecosystems: a study of a subtropical estuary in Brazil

ABSTRACT Lima, N. G.B, Galvani, E., Falcao, R. M. and Cunha-Lignon, M., 2013. Air temperature and canopy cover of impacted and conserved mangrove ecosystems: a study of a subtropical estuary in Brazil. In: Conley, D.C., Masselink, G., Russell, P.E. and O'Hare, T.J. (eds.) The aim of this study was to analyze and compare the variation of air temperature between impacted and conserved mangrove areas by monitoring the microclimate and canopy cover of mangrove forests in the southern coast of Sao Paulo State, Brazil. Data were collected from September 2011 to August 2012 using meteorological towers installed below the canopy at a height of 2 m. Hemispherical photographs were processed to acquire the canopy opening and Leaf Area Index, which quantifies the area with leaves, trunks and branches. The mangrove vegetation structure was characterized in permanent plots located in conserved and impacted areas. All plants were identified and described. Evaluations of the temperature data using Pearson linear correlat...

Kondisi ekosistim mangrove di sub district Liquisa Timor-Leste

Abstract. The objective of the present study was to determine the condition of the mangrove ecosystem and how to the influence of physic-chemical environment parameters on community structure of mangrove vegetation in Kaitehu Tibar and Ulmera in Bazartete coastal areas District of Liquisa, Timor-Leste. The parameters observed include the condition of mangrove vegetation, soil substrates, plankton abundance and Nutrient Elements in the area. The results showed that, the Sonneratia alba species is the most dominating in Bazartete area, compared with Rhizophora and Brugueira cylindric species, ie 967 threes /ha, 967 threes /ha, and 1333 threes /ha, The results of laboratory analysis quality of physical-chemical conditions of the environment shows that, there are significant differences in soil nutrient substrate in the 3 observation areas. such as follows: Substrate ground, the average content of C-organic were 0.67%, 2.47% and 0.21%, K = 1.17 Me/100g, 1.20 Me/100g , and 1.14 Me/100g; Ca = 32.39 Me/100g, Me/100g 25.83, and 27.09 Me/100g; Me/100g Mg = 11.46, 9.81 and 9.78 Me Me/100g / 100g; Me/100 g Na = 8.47, 8.26 and 9.78 Me/100g Me/100g. The cation concentration at each observation areas is : K = 0.023 mg / l, 0.023 mg / l and 0.046. Ca = 0.05 mg / l, 0.04 mg / l and 0.04 mg / l. Mg= 0.02 mg / l, 0.03 mg / l, 0.026 mg / l, and Na = 0.03 mg / l, 0.03 mg/l and 0.02 mg/l.Keywords. Mangrove ecosystems, mangrove environment habitats, organic matter, Calsium and Magnesium

Predation risks for juvenile fishes in a mangrove estuary: A comparison of vegetated and unvegetated microhabitats by tethering experiments

Predation rates for juveniles of three fish species, the resident cardinal fish Apogon amboinensis, vagile mojarra Gerres erythrourus and benthic resident sand goby Favonigobius reichei, were compared in a creek between a mangrove-root area (fringing area with submerged portions of mangrove roots) and a bare sand area (unvegetated central area) in the Urauchi River mangrove estuary, Iriomote island, southern Japan, by daytime tethering experiments. A. amboinensis, occurring restrictedly in the mangrove-root area, hovered inactively near mangrove roots during the day. The other two species, on the other hand, inhabited both mangrove-root and bare sand areas, G. erythrourus swimming actively and speedily in the water column and F. reichei resting immobile on the substratum, its body coloration similar to the later. The predation mortality rate of A. amboinensis was significantly lower in the mangrove-root area than the bare sand area, whereas no differences in the rates for G. erythrourus and F. reichei were found between the two microhabitats. In addition, species and individual densities of piscivorous fishes, determined from a visual census, were significantly higher in the mangrove-root area, suggesting that the potential predation risk was not necessarily lower. The lower mortality rate of A. amboinensis in such a predator-rich area may be due to their anti-predator tactic associated with mangrove structural complexity, sheltering behind mangrove roots when disturbed by predators. The similar mortality rates of the other two species between the microhabitats may have resulted from anti-predator tactics independent of mangrove vegetation structure, such as rapid flight and cryptic body coloration.

Effects of the physical structure of mangrove vegetation on a benthic faunal community

Clarification of the role of the physical structure of mangrove for benthic faunal communities was sought by investigating the impacts of canopy shade and root structure on (1) the physical environment, including temperature, moisture and grain size of the substrate sediment, (2) benthic faunal distribution, and (3) food resource availability, using a field manipulated experiment at an intertidal mangrove forest around Sikao Creek, Trang Province, Thailand. Five treatments were established, including artificial shade cover, root simulated structure, mix (shade and structure) and control of the canopy gap (which had no mangrove vegetation), in addition to forest control under the mangrove canopy. Following 18 months of observation, species' richness and abundance of epifauna were found to have increased in shaded treatments, which had low temperature and high moisture substrate. Food resource conditions had also altered from abundant microphytobenthos (relatively high nutritional values) to enriched mangrove detritus due to shading. These results indicated that the physical structure of mangrove vegetation facilitates the habitation of intertidal epifauna, canopy shade having an important function in providing cooler wetter surface substrate, despite also inducing a reduction of favorable food resources (i.e. microphytobenthos).

Transitions in Ancient Inland Freshwater Resource Management in Sri Lanka Affect Biota and Human Populations in and around Coastal Lagoons

The increasing anthropogenic pressure on natural environments results in impacts that affect tropical forest areas and their biodiversity. Adverse impacts on terrestrial and oceanic environments often compound in the intertidal area, where mangrove forest ecosystems thrive. In tropical coastal areas of many developing countries where people depend on wood and other mangrove forest products and services, forest degradation leads to socioeconomic problems. At the same time, increasing freshwater needs in these areas are expected to cause additional problems. On the basis of remote sensing and ground truthing complemented by colonial archival material from the Dutch East India Company (1602-1800), we report that changes to the historic system of inland freshwater management have increased dramatically in recent times. Hydrological changes, such as interbasin transfers, have resulted in a qualitative ecological and socioeconomic degradation in three coastal lagoons in southern Sri Lanka. Variations in river hydrology have caused changes in the areas suitable as mangrove habitat and, thus, have resulted in an altered distribution. However, increases in mangrove area can mask the degradation of the site in terms of floristic composition, significance of the species, and biodiversity (this effect is termed "cryptic ecological degradation"). It is important that such changes be carefully monitored to ensure biological and socioeconomic sustainability.

Mangroves of Arid Environments in Puerto Rico and Adjacent Islands

The structure of mangrove vegetation, soil salinity, and topographic relief of the mangrove ecosystem were studied along the south coast of Puerto Rico, Culebra, and Mona Island. All systems, with the exception of the forest at Mona Island, were characterized by having a coastal fringe of live vegetation (usually dominated by the red mangrove), a zone of dead trees, and a hypersaline lagoon or dry salt flat on the landward side. Mean soil salinities were 44 0/00 for the zone of live trees, 72 0/00 for the zone of dead trees, and 87 0/00 for the salt flats. The Mona Island forest grew over a sandy hardpan that prevented mixing of sea water and the fresh water. Soil salinities were low in this forest, and trees reached a height of 15 m. Tree height was inversely proportional to soil salinity (r = 0.72) between 17 and 72 0/00. When soil salinities exceeded 65 0/00, dead tree basal area was higher than live tree basal area. It is suggested that mangrove growth is limited by soil salinities higher than 90 0/00. Mangrove succession in offshore overwash islands and arid coastlines is described. It is proposed that cyclic rainfall patterns and hurricanes act as regulators of speed and direction of succession. Rainy periods are associated with lower soil salinities and expansion of the red mangrove zone. Droughty periods result in high soil salinities, mangrove mortality, and expansion of salt flats. Hurricanes set back succession and reverse successional trends that reduce mangrove areas. A model of mangrove ecosystem function and implications for management are also discussed.