Mangrove Structure Research Articles

STRUKTUR VEGETASI MANGROVE DI PESISIR PANTAI DESA DAMBALO KECAMATAN TOMILITO KABUPATEN GORONTALO UTARA

Mangroves are tropical coastal vegetation communities dominated by several unique tree species that can be affected by tides. Damage to mangrove forests can be caused by two main factors, namely human activity factors and natural factors. The purpose of this study was to analyze the structure of mangrove vegetation by looking at density, frequency, Impact Value Index (IVI) and species diversity (H ') on the coast of Dambalo Village, Tomilito Sub-district, North Gorontalo District. The method used is a combination of the path method and the checkered line method so that measuring squares are created within the paths. The results showed that the number of mangrove diversity was 11 species, with the Importance Value Index at the tree level of the Rhizophora apiculata species having the highest value of 61.28% and the seedling phase with the same species Rhizophora apiculata having the highest index of importance of 29.80%. The main conclusion from this research is that the mangrove vegetation structure has an abundant level of species diversity. This shows that the index of species diversity in mangrove vegetation is H '= 2.2692 that species diversity is abundant.

Impacts of sea-level changes on mangroves from southeastern Brazil during the Holocene and Anthropocene using a multi-proxy approach

Globally, mangroves are expected to move inland as sea-level rises. However, local characteristics mainly related to mangrove structure, geomorphology and coastal hydrodynamics may change the mangrove response to sea-level rise. The most useful evidence to support projections for the future likely comes from mangrove history reconstruction corresponding to past sea-level changes. This study characterized modern (1985–2018 CE) and past (<6300 cal yr BP) mangrove dynamics according to sea-level changes along two estuarine valleys on the southeastern Brazilian coast to predict the mangrove response to sea-level rise by 2100. Relative Sea-Level (RSL) rise triggered changes from a tidal flat occupied by herbs, palms, tree/shrubs to a lagoon surrounded by mangroves between ~6300 and ~4230 cal yr BP. More recently, the RSL fall converted that lagoon into flats occupied by herbs, trees/shrubs, and palms on higher surfaces, and mangroves on lower flats during the mid-late Holocene. The last thousand years were characterized by a mangrove contraction between 390 and 77 cal yr BP, caused by a RSL fall. By contrast, mangrove expansion began at 77 cal yr BP (1873 CE) and continued after 1950 CE, migrating onto higher tidal flats previously occupied by herbs, palms, and trees/shrubs. Spatial-temporal analysis also indicated a mangrove invasion onto higher flats since 1985 CE. These trends are likely related to RSL rise since the end of the Little Ice Age and they intensified during recent decades, when the lower mangrove boundaries remained stable, and mangroves expanded to higher surfaces. Mangroves, confined between steep surfaces, will expand ~22ha under the influence of a sea-level rise of 98cm by 2100. However, an upstream mangrove migration by 2100 on low and extensive fluvial plains (~4030 ha) will depend mainly on the interaction between fluvial discharge/sea-level rise.

The Distribution and Structure of Mangroves (Avicennia germinans and Rhizophora mangle) Near a Rapidly Changing Range Limit in the Northeastern Gulf of Mexico

The Distribution and Structure of Mangroves (Avicennia germinans and Rhizophora mangle) Near a Rapidly Changing Range Limit in the Northeastern Gulf of Mexico

Vegetation structure, biomass and carbon retention capacity of mangroves at Northeast coast of Sri Lanka

The Ceylon Journal of Science is published by the University of Peradeniya, Sri Lanka. Full text available. The journal also has its own website. The Ceylon Journal of Science is a continuation of the Ceylon Journal of Science (Biological Sciences) which is no longer being published as a separate journal. The history of the journal can be found here.From May 2020, Ceylon Journal of Science is indexed in DOAJ.

Modeling mangrove responses to multi-decadal climate change and anthropogenic impacts using a long-term time series of satellite imagery

Determining the effects of simultaneously operating climate change and anthropogenic impacts on mangroves remains a challenge for the Persian Gulf and the Gulf of Oman. The objective of this study was to spatially quantify the spatial extents and biomass of dwarf and tall mangroves in response to drought intensities (Standardized Precipitation Index, SPI), sea-level rise (EC), land use/land cover change (LULC), and surface runoff and freshwater inflow to upstream mangrove catchments along the coasts of southern Iran over a 35-year period (1986–2020). The study drew on a long-term time series of 105 Landsat satellite images, maritime data, rainfall data, field surveys, and models to quantify independent variables (i.e., the WetSpass-M model to quantify surface runoff) and mixed models analysis to determine the important drivers of change. Although mixed model analysis indicated that sea-level rise was the main climate change driver of the development of spatial extents and biomass of both tall and dwarf mangroves, its influence was embedded in the larger temporal climate context of the region. Our findings show that spatial extents and biomass development are neither tightly coupled nor developed temporally or directionally synchronously in dwarf and tall mangroves. This study also shows a precipitous decline in rainfall amounts, SPI, and freshwater runoff volumes starting in 1998. The ensuing long-term drought that is still ongoing but decreased slightly in intensity in the last few years shaped the overall spatiotemporal development pattern of the mangrove structures over the entire study period. The correlation between biomass and the independent variables was similar for dwarf and tall mangroves and was positive with SPI and runoff amounts and negative with EC in all three study sites.

Mapping multi-layered mangroves from multispectral, hyperspectral, and LiDAR data

Understanding species distribution and canopy structure of mangrove forests is imperative for flora and fauna conservation in mangrove habitats. However, most mangrove studies focused on the top canopy layer without exploring the vertical structure of mangroves. This paper presents multi-layered mangrove mapping which considered both overstory and understory detection and species classification using multispectral WorldView-3 (WV-3) data, airborne hyperspectral images (HSI), and LiDAR point cloud. First, LiDAR returns were stratified into the overstory and understory by analyzing the profile of return height, which helped understand the vertical structure of the mangrove stands. Second, three classification algorithms Random Forest (RF), Support Vector Machine (SVM), and Convolutional Neural Network (CNN) were compared by applying WV-3, HSI, LiDAR data, and their combinations to map seven vegetative species. Feature selection was conducted to identify important features and the optimal feature size prior to classification tasks. The measured and estimated understory canopy heights reached a high correlation coefficient of 0.71, which demonstrated the effectiveness of using LiDAR data and the proposed procedure to stratify multi-layered canopies. The combined HSI and LiDAR data produced satisfactory results by the three classifiers with overall accuracy (OA) varying from 0.86 to 0.88. And the species was also accurately mapped by integrating WV-3 and LiDAR data using both RF and SVM algorithms with OA attaining between 0.84 and 0.86. The results of this study highlight that (1) LiDAR data provided superior information to map the vertical structure of multi-layered mangroves, which provided valuable information to classify single-layered and dual-layered Kandelia obovata with understory beneath; (2) the combination of spectral and LiDAR features improved mangrove species classification; (3) and species mapping results derived from combined datasets appeared to be more influential by LiDAR features when using RF and SVM, but spectral features played a more important role in CNN.

Struktur Vegetasi Mangrove berdasarkan Karakteristik Substrat di Pantai Karang Sewu, Gilimanuk Bali

Karang Sewu Beach is one of the areas in the West Bali National Park (TNBB) which has a natural mangrove ecosystem. One of parameters affecting mangrove growth is substrate. This research aims to determine the vegetation structure, substrate characteristics, and different vegetation groups of mangroves based on its substrate characteristics in Karang Sewu Beach. This study collected the data on vegetation structure using a plotted line method with 2x2, 5x5, 10x10 and 20x20 meters transects. Substrate texture was analyzed using a pipette method while total organic material was analyzed using the Loss on Ignition (LOI) method. Mangrove vegetation was categorized based on substrate characteristics using the descriptive quantitative method. Results showed there were nine species of mangrove found in Karang Sewu Beach, namely Ceriops tagal, Sonneratia alba, S. caseolaris, Rhizophora apiculata, R. mucronata, R. stylosa, R. lamarckii, Lumnitzera racemosa, and Avicennia marina. INP in the first station was dominated by R. apiculata for tree levels (152,88 %), pole (174,24 %), sapling (139,04 %), and seedling (111,48 %). R. lamarckii dominated the second station with a tree level value of 226,94 % while C. tagal dominated for pole level (220,82 %), sapling (243,65 %), and seedling (182,94 %). INP in the third stasion was dominated by C. tagal for pole level (103,68 %), sapling (98,77 %) and seedling (95,51 %). Mangrove substrate in Karang Sewu Beach was characterized as having a sand like texture, dusty loam, sandy loam, loamy sand, and sandy clay with moderate organic matter (2.44 %) to low (0.79 %). Mangrove vegetation grouping based on substrate characteristics in Karang Sewu Beach was different in general. A. marina is found in the middle zone, where this species is usually found in the front zone.&#x0D;

STRUKTUR KOMUNITAS VEGETASI MANGROVE DI PESISIR UTARA PULAU MENDANAU DAN PULAU BATU DINDING, KECAMATAN SELAT NASIK KABUPATEN BELITUNG

Mendanau Island and Batu Dinding Island are part of small island groups that have a high diversity and density of mangroves. Based on administratively, Mendanau Island is located in the coastal area of Simpang Pesak District, Belitung Regency, which consist of one large island (Mendanau Island) and 1 small island (Batu Dinding Island). The lack of data about potential, diversity, and community structure of mangroves on the north coast of Mendanau Island and Batu Dinding Island, therefore this research is needed as a database for planning, sustainability management of mangroves at the coastal area and small island. The data of mangrove vegetation was taken by purposive sampling method, with using line transect plot (LTP). Ilustration of sampling design is each line transect have 3 plot / kuadratic transect sized 10 m x 10 m (capling), 5 m x 5m (sapling), 1m x 1 m (seedling). The result showed that there are 12 (twelve) mangrove species were found: jenis S. alba, R. apiculata, R. stylosa, R. mucronata, B. gymnorhiza, X. granatum, L. littorea. S. hydrophyllacea, S. taccada, H. tiliaceus, Pandanus, dan I. pes-caprae. Mangrove community structure and mangrove condition on the North Coast of Mendanau Island, at several observation stations, was damaged (poor conditions), while the status of the mangrove conditions on Pulau Batu Dinding was still relatively good

Short Communication: A comparison of stand structure, species diversity and aboveground biomass between natural and planted mangroves in Sikka, East Nusa Tenggara, Indonesia

Abstract. Matatula J, Afandi AY, Wirabuana PYAP. 2021. Short Communication: A comparison of stand structure, species diversity and aboveground biomass between natural and planted mangroves in Sikka, East Nusa Tenggara, Indonesia. Biodiversitas 22: 1098-1103. The effectiveness of mangroves reforestation can be evaluated by comparing the stand dynamics of planted mangroves with natural mangroves in similar site conditions. This study investigated stand structure, species diversity and aboveground biomass between natural and planted mangroves in Sikka, East Nusa Tenggara. A field survey was conducted using quadrat transect method for vegetation measurement, especially related to species composition and its size distribution. Several parameters were recorded in field observation, including number of species, diameter, height, volume, and aboveground biomass. The stand structure of both mangroves was demonstrated by the distribution of diameter class while the species diversity was described using three parameters, i.e., richness, heterogeneity, and evenness. Moreover, the IVI of each species recorded was also calculated to understand the contribution of species in the mangrove ecosystems. The comparison of stand characteristics between natural and planted mangroves was examined by Mann-Whitney test and Spearman Correlation was also applied to understand the relationship between IVI and aboveground biomass. The results showed that the diameter and height between the natural and planted mangroves significantly differed (P&lt;0.05). In contrast, there was no significant difference in tree density, volume, and aboveground biomass (P&lt;0.05). The stand structure of both mangrove stands followed the pattern of J-inverse in which the frequency of trees decreased with the increase in diameter class. Species diversity in both stands was statistically equal in richness, heterogeneity, and evenness (P&gt;0.05) even though there were some specific species which only observed in the natural or planted mangroves. The most superior species in the planted mangroves was Rhizophora mucronata (IVI = 96.99) while the most important plant in the natural mangroves was Sonneratia alba (IVI = 82.49). Our study found there was a significant correlation between IVI and aboveground biomass in which species with higher IVI indicated greater aboveground biomass. Based on these findings, restoration efforts of degraded mangroves in Sikka have been effective. The restoration, which has been conducted for almost three decades, has not only brought back its vegetation cover but also the functional traits of the mangrove stand to mimic with natural mangroves in the area.

Vegetative structure and zonal distribution of true mangroves in Shwe-Thaung-Yan coastal areas, Myanmar

The survey was conducted in the mangrove forests around the Magyi and Utto Creeks at Shwe-Thaung-Yan coastal areas in Ayeyarwady Delta region, April 2018. Transect lines were laid as lower, middle and upper, and quadrate plots based on Point Center Quarter Method (PCQM) P-DATA PRO were used. A total of 15 species of true mangrove was recorded. Rhizophora apiculata and Bruguiera gymnorhiza are the most dominant and distributed species in the study area. Followed by Bruguiera sexangulata, Cerop tagal and Rhizophora mucronata then remaining species. Zonation pattern of mangroves species as lower, middle, upper was also examined in study areas. Among than 1 species in Near Threaten (NT), 1 species in Critically Endangered (CR), 1 species in Endangered (EN) and remaining species are Least Concern (LC) had been considered according with IUCN red list. The environmental parameters such as water salinity and temperature, soil salinity, soil temperature and soil pH of study area were also recorded.

MANGROVE GROWTH DYNAMICS AND SEDIMENT RELATIONS IN SOUTH WESTERN NIGERIA

The mangrove ecosystem is not exempted from the fundamental interlinkages of components ensuring their functionality and development. Proper understanding of the interrelations between sediment parameters and their potential influence on mangrove growth is limited. This study examined mangrove structure across South western Nigeria, their growth dynamics, successional stage and relationship with the underlying sediments. Vegetation measurements and soil sampling (0-30cm) were carried out in one hundred quadrats of 20m by 20m. Sediments underwent laboratory analysis using standard procedures. Multiple regression was used to evaluate the relationship between the sediments and structural parameters at the 0.05 significance level. Ongoing degradation was detected, with evidence of selective harvesting targeted in the critical younger classes of &lt;6cm, 6.1-9cm and 9.1-13cm. Phosphorus, magnesium, pH, salinity, sodium, silt and organic carbon were significant factors, contributing approximately 53 percent to the height. Electrical conductivity, organic carbon, salinity, total acidity, pH and silt were significant factors, contributing approximately 56 percent to the girth. The mangrove forests, though at a matured stage, are endangered. Sediment parameters, especially texture, have a significant influence on mangrove growth. Preparation of specialised sediment treatments for mangrove regrowth sites and also the setting up of conservation sites should be adopted.

Study of Molluscs Diversity as Ecosystem Engineer from Beach of Sungai Bakau Village, Tanah Laut, South Kalimantan

Molluscs are engineered biota that play an important role in changing the structure and function of ecosystems, including coastal and mangroves. This study aims to record the diversity of molluscs as a group of engineers in coastal areas in Sungai Bakau Village, Tanah Laut, South Kalimantan. Purposive random sampling method was used to obtain mollusc data at three observation stations (Station 1 : sandy beaches, Station 2 : rocky beaches, and Station 3 : river estuaries). Only one type of bivalve was found (Meretirix meretrix) and 13 types of gastropods (Nassarius Sp., Turricula javana, Cerithidea alata, Polygona angulate, Distorsio decipiens, Latirus pictus, Bursa granularis, Latirus sp., Littorina undulate, Naticarius hebraeus, Murex. elenensis, Neverita didyma, and Turritella terebra). The highest diversity index (1.95) was found at station 1. While the evenness index is 0.755. Similarity index was 92.85% (stations 1-2 and stations 1-3) while at stations 2-3 was 85.71%. The highest density of Cerithidea alata is reached 2,996,700 ind/Ha and the least was Turritella terebra (20,000 ind/Ha). Water parameters between observation stations were close to each other : pH ± 7.6 - 7.7, temperature ± 29.3 - 29.7 0C, and salinity ± 34.9 - 35.4 ppt. The difference between research stations can be seen from sediment content. Station 1 has the highest sand content (96.2%). Station 2 consists of 64.7% sand dust and 20.6% clay. Station 3 has the highest dust content, reaching 84.6%. The types and presence of mollusks (bivalves and gastropods) at each research station is vary in value.

Comparison of prey availability for &lt;i&gt;Setophaga petechia gundlachi&lt;/i&gt; (Aves: Parulidae) between two mangroves with different vegetation structure

The subspecies Setophaga petechia gundlachi is characterized by its specificity to mangrove habitat during the breeding season. The objective of this work was to compare the prey availability for S. petechia gundlachi during the breeding season in two mangrove sites with different vegetation structure in Havana, Cuba. To describe different levels of vegetation structure between both mangrove sites, we took several variables at 50 plots. Besides, we recorded the foraging behavior of S. petechia gundlachi to establish the design of prey availability sampling. We measured prey availability by using the branch clipping method, about 90 samples were collected at each mangrove site. Bajo de Santa Ana mangrove, with a lower height and diameter at breast height, showed evidence of deforestation. Laguncularia racemosa was the most used mangrove species for foraging and offered the highest biomass of available prey in the Laguna de Cobre-Itabo mangrove site. The greatest biomass of available prey was found at the Laguna de Cobre-Itabo, with a value of 5.1 (CI: 4.0 - 6.2) mg / 100 g of branch clipping. The Bajo de Santa Ana site had a lower value than expected 1.6 (CI: 0.8 - 1.7) mg / 100 g of branch clipping. The results provide evidence of the possible influence of mangrove vegetation structure changes on food availability for S. petechia gundlachi in this urban landscape.

Mangrove associated macrobenthos community structure from an estuarine island

Abstract. Rahman MDH, Hossain MB, Habib A, Noman MDA, Mondal S. 2021. Mangrove associated macrobenthos community structure from an estuarine island. Biodiversitas 22: 247-252. Macroinvertebrate living on or around the mangroves has not been or less investigated in Bangladesh. This study was carried out to describe the density, distribution, and community structure of mangrove associated macrobenthos in Nijhum Dwip, central coast of Bangladesh. A total of 17 taxa were identified belonging to mainly Polychaetes (67.37%), Mysids (23.53%), Isopods (3.83%), Amphipods (0.58%), and Gastropods (0.29%). Polychaetes were dominant by contributing 67.37% of total macrobenthos. The number of benthic fauna ranged from 359 to 1617 inds./m2 with a mean value of 1003.93± 400.3 inds./m 2 There was no significant difference observed (p &gt; 0.05) in the abundance of macrofauna among the stations. The maximum Shannon-Wiener Index (H’) of species diversity was found at St2 (1.323) and the lowest at St4 (0.8) in the monsoon period possibly due to high rainfall and disturbance of benthic habitat. The Shannon-Wiener diversity values suggest the area was less polluted. The information from the present study can be used to measure the impacts of pollution to conserve biodiversity in sustainable manner.

ANALYSIS OF SHORELINE CHANGE IN COASTAL AREA OF SUBANG WEST JAVA INDONESIA FROM 2010 TO 2019 THROUGH SATELLITE IMAGERY

The condition of beaches in Indonesia is currently quite concerning. Indonesia's mangroves and coastal sand are in danger of being damaged. Commitment from all parties is needed to overcome coastal damage. If not, the negative impact will be dangerous for the existence of coastal communities. Damage to coastal is a serious threat to the surrounding ecosystem, even tends to harm humans. Not only waste carried by the flow into the sea, but also garbage disposed of around the coastal areas of the sea and poor land management are clearly some actions that can reduce the carrying capacity of the environment. This carriage a serious threat to the environment. The beach in Subang district, West Java has quite severe coastal damage. Analysis of shoreline changes is needed to overcome the damage to the coast. The method used to analyze shoreline changes is through satellite mapping using Google Earth. The results obtained from 10 years of coastline satellite mapping in Subang Regency are changes in coastline and area that occur due to erosion and/or accretion. These results will help to challenge erosion and/or accretion. The next step can be made a coastal protection in the form of mangrove plants or coastal protection structures.

Larval fish assemblage, diversity and habitat ecology in the Matang Mangrove Ecosystem, Perak, Malaysia

Aim: In this study, habitat ecology, abundance and diversity indices were combined to characterize spatial distribution and seasonal patterns of larval assemblages at three sites with different levels of disturbance at Matang mangrove ecosystem. Methodology: Three sampling stations were selected, namely S1 - most disturbed, S2 - moderately disturbed? and S3 - least disturbed. Larval fishes were collected using oblique tows of a bongo net (450 μm mesh size) equipped with a flow meter every month for one year from April 2015 to March 2016. A total of 14 families were identified with nine families dominating at S1, eight at S2 and 10 at S3. Results: Gobiidae was the most abundant at 80.68% total abundance, followed by Mullidae (3.26%), Rachycentridae (3.07%), Blenniidae (3.01%), Engraulidae (2.22%) and Ambassidae (1.68%). The highest and lowest Shannon-Wiener diversity index was recorded at S3 (H'=1.04) and S1 (H'=0.35), respectively. Water temperature showed a positive significant correlation with Blenniidae (p < 0.05) and a negative significant correlation with Gobiidae and Syngnathidae (p < 0.05). Similarly, Gobiidae and Syngnathidae were negatively correlated with salinity, TDS, conductivity and pH. However, multiregression analysis indicated a weak overall relationship (4 - 41%) between larval abundance and environmental variables. This suggests that habitat structure of mangroves was more important in determining larval abundance than water quality. Interpretation: This study emphasizes the need to conserve mangrove ecosystems as important nursery grounds for various fish larvae to ensure adequate recruitment and ultimately sustainable fisheries management.

High variance in community structure and ecosystem carbon stocks of Fijian mangroves driven by differences in geomorphology and climate

Mangrove ecosystems are particularly important for small island developing states of the Pacific, such as Fiji, which are at the forefront of the impacts of climate change. This is because of the ability of mangroves to mitigate storm surges and floods as well as their high carbon sequestration and storage capacity. However, there are few detailed studies on the spatial variation in mangrove structure and carbon stocks in Fiji, and this information is essential to support decision making by government and communities, enabling the development of effective mitigation and adaptation responses. We assessed mangrove forest structure in contrasting regions around Fiji's largest island, Viti Levu, within sites managed by indigenous (iTaukei) Fijians. Mangroves of the Ba, Nadroga-Navosa, and Rewa and Tailevu regions showed high variance in both structural complexity and ecosystem carbon stocks. Levels of variation were similar to that observed globally due to variable geomorphological and biophysical settings related to orographic rainfall, freshwater influx, tidal amplitude and cyclonic disturbances. High biomass, structurally complex forests occur on the wetter south-east coast (e.g. the Rewa Delta), while structurally uniform scrub mangroves dominate large areas of mangroves along the north-west (e.g. the Ba Delta) and west coast (e.g. the Tuva Delta). Mangroves of the Ba region displayed considerable damage from tropical cyclones, particularly in taller vegetation. All mangrove sites assessed were important reservoirs of carbon, with results when scaled to the spatial extent of mangroves in Fiji revealing that ecosystem carbon storage is disproportionate to area and equates to 73.3% of the carbon held within terrestrial rainforests, despite occupying just 7.3% of the total area. This underscores the importance of mangroves as valuable carbon sinks in Fiji and the need to develop incentives for improved conservation and restoration.

Decomposition of mangrove litter under experimental nutrient loading in a fringe Rhizophora mangle (L.) forest

Carbon (C) cycling is an important attribute of mangrove forests that relates to the structure, function, and resilience of mangroves under environmental change. Increased nutrient enrichment in tropical coastal waters may influence C cycling through organic C mineralization. For example, by alleviating nutrient limitation of the heterotrophic microbial community, nutrient enrichment may enhance C mineralization and facilitate a loss of within-stand C sequestration. Here, we enriched a coastal fringe Rhizophora mangle (L.) mangrove system for two years with two fertilizer regimes to mimic agriculture runoff (”+high” N:P ratio of 50:1) and urban runoff (”+moderate” N:P ratio of 16:1) scenarios as follows: (1) annual loading rate of 70 g N m −2 year −1 and 3.1 g P m −2 year −1 or (2) annual loading rate of 70 g N m −2 year −1 and 9.7 g P m −2 year −1. C mineralization was measured as microbial respiration rates from the forest floor and litter decomposition rates. While decomposing leaf litter and green leaves had lower molar C:N under the +moderate N:P fertilization course, neither fertilization scenario produced an effect on C mineralization processes compared with ambient conditions. Substrate CO 2 flux rates were not different among treatments and ranged from 1.15 to 1.81 μmol CO 2 m −2 s −1 (3.0–4.8 g CO 2 m −2 day −1) following 72 weeks of fertilization and 0.58–1.55 μmol CO 2 m −2 s −1 (1.5–4.1 g CO 2 m −2 day −1) 30 weeks following the end of the experiment. Time to 50% decay of above-ground leaf litter ranged from 61 to 110 days (average 79 days). Below-ground leaf litter material was fully decomposed by 22 months after burial. A15 N pulse-recovery suggests that the majority of the retained fertilizer (22.2 ± 4.4% at 10 months following spike) was taken up by fine roots, though this did not significantly affect CO 2 flux from the forest floor. This work demonstrates that nutrient enrichment by aqueous delivery does not strongly affect organic carbon mineralization in a coastal fringe mangrove within two years. Environmental conditions, substrate quality, and location may play a more substantial role in mangrove C dynamics compared with short-term aqueous-based nutrient enrichment.

Non-linear wave attenuation quantification model improves the estimation of wave attenuation efficiency of mangroves

The wave attenuation function of mangroves follows the Dalrymple model but changes nonlinearly with vegetation structure in various places, which has not been fully addressed. Here, taking the Da Guan Sha of Beihai city, China, as a case study, the landscape metrics characterizing mangrove structures, including the diameter at breast height (DBH), crown breadth, crown density, and rhizome and stem systems, were obtained through remote sensing and field measurements. Then, the nonlinear spatiotemporal pattern of the wave attenuation function (decreasing rate of wave height) was explored and revealed among six 20х200 m parallel transects passing through mangroves along the direction of the current. The results showed the following: (1) The DBH and crown breadth first increased and then decreased from the seaward to landward side of each transect, showing a nonlinear inverted "U" pattern of distribution. (2) The wave attenuation function of mangroves was dominated by the canopy at high tide but significantly affected by the structure of the rhizome or stem system at low tide. The wave height during a specific storm surge could decrease by nearly 97% among the six transects at high tide but by only 87% at low tide on average if the wave crossed through the mangroves over a distance of ≥100 m from the seaward side of the mangroves edge. (3) The wet surface width of a major part of mangrove trees with wave attenuation functions would change with the distribution of the DBH, crown breadth, and tree height along the transects, which would also change with the dynamics of the water level. The wave attenuation of mangroves ranged from 85% to 90% at low tide and from 96% to 97% at high tide if the wave crossed through mangroves at a distance of ≥100 m from the seaward side of the mangrove edge. (4) The predicted practical decreasing rate of wave height based on the forward differencing method (a method that considered the varied vegetation structure along transects in the model during the calculation of wave attenuation, which would be close to reality) would be 12% and 9% higher at low and high tide, respectively, than those estimated by the simplified calculation method (a method of taking the average value of the vegetation structure of each transect to calculate wave attenuation) if the wave crossed through mangroves at a distance of ≥200 m from the seaward side of the mangrove edge. The integration of mangrove structures into the established empirical models improves our understanding of the nonlinear wave attenuation function of mangroves and may provide decision makers with more valuable information on restoring mangrove ecosystems to protect against storm surges.

Evaluation of the mangrove system in the estero "Arroyo los Coamiles" (Punta de Mita, Nayarit, Mexico)

In March 2019, the current state of the mangrove structure in the Arroyo los Coamiles estuary (Punta Mita Bay, Nayarit) was evaluated. The method of circular plots centered on a point was used (Cottam and Curtis, 1956). The mangrove structure is made up of the species Laguncularia racemosa, Avicennia germinans, Conocarpus erectus and Rhizophora mangle. The greatest forest development is found in the second third of the estuary with a bordercontinental structure. The average height of the mangroves was 6.17 m, (SD 7.35 m), the diameter at breast height was 19.21 cm and the total basal area was 57.36 m2 . The data are associated with young trees in a good state of development and conservation. The C / N ratio was determined as an index of the quality of the soil organic substrate, the values ranged between 3.74 and 14.91 and the percentage of organic matter was from 1.45 to 8.04. The fragility of the soils reinforce the proposal to take care of the natural drainage of the property. Mangroves have been impacted by tourist developments around the world, the environmental and economic benefits that these ecosystems provide are ignored by inhabitants and authorities, which allow their destruction.