A functional analysis reveals extremely low redundancy in global mangrove invertebrate fauna.

Deforestation results in habitat fragmentation, decreasing diversity, and functional degradation. For mangroves, no data are available on the impact of deforestation on the diversity and functionality of the specialized invertebrate fauna, critical for their functioning. We compiled a global dataset of mangrove invertebrate fauna comprising 364 species from 16 locations, classified into 64 functional entities (FEs). For each location, we calculated taxonomic distinctness (Δ+), functional richness (FRi), functional redundancy (FRe), and functional vulnerability (FVu) to assess functional integrity. Δ+ and FRi were significantly related to air temperature but not to geomorphic characteristics, mirroring the global biodiversity anomaly of mangrove trees. Neither of those two indices was linked to forest area, but both sharply decreased in human-impacted mangroves. About 60% of the locations showed an average FRe < 2, indicating that most of the FEs comprised one species only. Notable exceptions were the Eastern Indian Ocean and west Pacific Ocean locations, but also in this region, 57% of the FEs had no redundancy, placing mangroves among the most vulnerable ecosystems on the planet. Our study shows that despite low redundancy, even small mangrove patches host truly multifunctional faunal assemblages, ultimately underpinning their services. However, our analyses also suggest that even a modest local loss of invertebrate diversity could have significant negative consequences for many mangroves and cascading effects for adjacent ecosystems. This pattern of faunal-mediated ecosystem functionality is crucial for assessing the vulnerability of mangrove forests to anthropogenic impact and provides an approach to planning their effective conservation and restoration.

Diversity of perspectives in biodiversity conservation: A case study of port land use in Antwerp and Rotterdam.

Conflicts of interest often undermine conservation initiatives against biodiversity decline. Effective decision-making requires a deeper understanding of the positions, criteria, concerns, and perspectives of stakeholders. However, managing so many perspectives can be difficult, and if not done well, conflicts arise which make it difficult to achieve conservation goals. The purpose of this study is to demonstrate that identifying areas of consensus is a good starting point to generate more effective debates and address complex issues. To do this, we investigate the diversity of perspectives regarding biodiversity conservation schemes among stakeholders in the studied ports of Antwerp and Rotterdam. Using Q-methodology, a semi-quantitative technique that enables us to systematically study the subjective views of stakeholders involved in a topic, we identified and organized a range of shared perspectives into three groups, known as factors. A total of 20 participants sorted 45 statements according to their perceptions and objectives, from -4 'most disagreeable' to 4 'most agreeable'. Then, respondents explained their rankings in a post-sorting interview. Next, the data was analyzed quantitatively and qualitatively. The quantitative analysis was conducted in two parts: (i) Dividing respondents into groups based on similar perspectives and (ii) coupling distinguishing statements with one of the factors characteristic of that viewpoint. Finally, in a qualitative analysis, we used the distinguishing statements and insights from interviews to create narratives and titles for the three factors: (1) Ports are key for our economic wealth, hence port development should continue, (2) Nature first, and (3) Multi-actor governance. Our findings confirm consensuses in three areas: policy, land use, and mitigation tactics. Interestingly, all narratives unanimously agreed on the importance of regulating port development and land use changes via legislation and environmental impact assessments. However, they debated the rigidity of legislation and whether offsetting port expansion (and associated land and resource use claims) should take place locally or internationally. We also found that decision-making mostly followed a human-centered perspective, where economic values were more relevant than intrinsic ones. These insights can serve as a baseline for stakeholders to form coalitions around areas of consensus to depolarize debates and avoid decision-making gridlocks.

The composition, distribution, and socio-economic dimensions of Ghana's mangrove ecosystems.

Mangrove ecosystems are recognised as one of the nature-based solutions to a changing climate. Notwithstanding the socio-ecological benefits of mangrove ecosystems, they are increasingly being destructed in some regions of the world. In Ghana, several studies have reported on the status, use, and management strategies of mangrove ecosystems in different sites of the country. However, these studies do not make it possible to appreciate the broader picture of Ghana's mangrove ecosystems since they are not synthesized into a single comprehensive report. This study uses the ROSES method for systematic reviews to report on Ghana's mangrove ecosystem distribution and species composition, as well as their socio-economic benefits, the anthropogenic and natural impacts on Ghana's mangrove ecosystems, and the management strategies and/or practices on Ghana's mangrove ecosystems. The study reveals there is no existing management strategy for Ghana's mangrove ecosystems, and therefore recommends the need to develop and implement policies and regulations that specifically target the protection and sustainable use of mangrove ecosystems in Ghana.

Mangrove management in Sri Lanka and stakeholder collaboration: A social network perspective.

Understanding the extent of collaboration among stakeholders is key to supporting mangrove management. Despite the existence of robust policies, collaboration among stakeholders of mangrove co-management remains largely unexplored in Sri Lanka. This was partly due to the civil war, natural disasters, and other socio-economic changes over the past 30 years. Our study aimed to identify the collaboration between stakeholders of mangrove management and their perceptions regarding mangrove co-management in Sri Lanka using social network analysis and content analysis. Surveys were conducted in all five coastal provinces of Sri Lanka. Stakeholders included in the study were from government departments, non-governmental organizations, and private institutes. Our results showed that there were differences between coastal provinces in the mangrove management networks, specifically in the number of stakeholders involved and their degree of collaboration. Some important stakeholders (for example the Land Use and Policy Planning Department) were excluded from the social networks in certain provinces (Eastern and Western provinces). There were various issues hampering effective mangrove management such as inefficient communication, inconsistencies between policies, and insufficient financial capacity of government stakeholders responsible for policy implementation. According to the stakeholders in our study, providing mangrove management initiatives with long-term collaboration, post-care, continuous monitoring, and funding may help to overcome these challenges. Additionally, we suggest the establishment of a common platform to coordinate stakeholders. We further encourage increasing the participation of academics, researchers, and students from national universities in the mangrove co-management of Sri Lanka. Insights from this island-wide survey can be adapted to mangrove and other natural resource management trajectories in other countries as well.

Interference competition as a key determinant for spatial distribution of mangrove crabs.

BACKGROUND: The spatial distribution of mangrove crabs has been commonly associated with tree zonation and abiotic factors such as ground temperature and soil granulometry. Conversely, no studies were designed to investigate the role of competition for resources and predation in shaping crab distribution in mangroves, despite these biotic factors are recognised as key determinants for spatial patterns observed in the communities colonising rocky and sandy intertidal habitats.We studied floral and faunal assemblages in two zones of a Sri Lankan mangrove, a man-made upper intertidal level and a natural eulittoral, mid-shore one. Leaf choice experiments were designed to study both feeding rate and intra and inter-specific interactions for food of sesarmid crabs in the two habitats in order to better understand crab spatial distribution. RESULTS: The two intertidal belts differed in terms of floral composition and crab species abundance. The eulittoral zone was strongly dominated by Neosarmatium smithi, while within the elevated littoral fringe four sesarmids (N. smithi, N. asiaticum, N. malabaricum and Muradium tetragonum) were more evenly distributed. At both levels, all sesarmids showed to collect significantly more Bruguiera spp. and Rhizophora apiculata leaves than Excoecaria agallocha ones. There was no temporal segregation in feeding activity among the four species, resulting in a high interference competition for leaves. Regardless of the habitat, N. smithi was always successful in winning inter-specific fights. CONCLUSIONS: Our results showed that the elevated littoral fringe was more crowded with crabs, but was less favourable in terms of food availability and environmental conditions. The dominance of N. smithi in gathering mangrove leaves suggests that this species may segregate the other sesarmids into less favourable habitats. The present data strongly suggest for the first time that interference competition for food can contribute to shape mangrove crab spatial distribution.

Mapping discourses using Q methodology in Matang Mangrove Forest, Malaysia.

The sustainable management of natural resources requires the consideration of multiple stakeholders' perspectives and knowledge claims, in order to inform complex and possibly contentious decision-making dilemmas. Hence, a better understanding of why people in particular contexts do manage natural resources in a particular way is needed. Focusing on mangroves, highly productive tropical intertidal forests, this study's first aim is to map the diversity of subjective viewpoints among a range of stakeholders on the management of Matang Mangrove Forest in peninsular Malaysia. Secondly, this study aims to feed the reflection on the possible consequences of the diversity of perspectives for the future management of mangroves in Malaysia and beyond. The use of the semi-quantitative Q methodology allowed us to identify three main discourses on mangrove management: i. the optimization discourse, stressing the need to improve the current overall satisfactory management regime; ii. the 'change for the better' discourse, which focuses on increasingly participatory management and on ecotourism; and iii. the conservative 'business as usual' discourse. The existence of common points of connection between the discourses and their respective supporters provides opportunities for modifications of mangrove management regimes. Acknowledging this diversity of viewpoints, reflecting how different stakeholders see and talk about mangrove management, highlights the need to develop pro-active and resilient natural resource management approaches.

How to catch the patch? A dendrometer study of the radial increment through successive cambia in the mangrove Avicennia.

BACKGROUND AND AIMS: Successive vascular cambia are involved in the secondary growth of at least 200 woody species from >30 plant families. In the mangrove Avicennia these successive cambia are organized in patches, creating stems with non-concentric xylem tissue surrounded by internal phloem tissue. Little is known about radial growth and tree stem dynamics in trees with this type of anatomy. This study aims to (1) clarify the process of secondary growth of Avicennia trees by studying its patchiness; and (2) study the radial increment of Avicennia stems, both temporary and permanent, in relation to local climatic and environmental conditions. A test is made of the hypothesis that patchy radial growth and stem dynamics enable Avicennia trees to better survive conditions of extreme physiological drought. Methods Stem variations were monitored by automatic point dendrometers at four different positions around and along the stem of two Avicennia marina trees in the mangrove forest of Gazi Bay (Kenya) during 1 year. KEY RESULTS: Patchiness was found in the radial growth and shrinkage and swelling patterns of Avicennia stems. It was, however, potentially rather than systematically present, i.e. stems reacted either concentrically or patchily to environment triggers, and it was fresh water availability and not tidal inundation that affected radial increment. CONCLUSIONS: It is concluded that the ability to develop successive cambia in a patchy way enables Avicennia trees to adapt to changes in the prevailing environmental conditions, enhancing its survival in the highly dynamic mangrove environment. Limited water could be used in a more directive way, investing all the attainable resources in only some locations of the tree stem so that at least at these locations there is enough water to, for example, overcome vessel embolisms or create new cells. As these locations change with time, the overall functioning of the tree can be maintained.

Human health risk attributed to consumption of seafood and recreation swimming in Negombo Lagoon, Sri Lanka: An assessment on lagoon water and inhabitant oysters (Crassostrea cucullata Born, 1778).

The Negombo Lagoon is a coastal lagoon influenced by local communities that introduce waste into its ecosystem. This study examined seven sewage entry points, out of which five sites were chosen for oyster sampling based on availability. Physicochemical and microbiological parameters of water (measured in triplicate at each site, n = 84) and oyster samples (total length, TL > 6 cm, n = 30) were assessed. Variation in regional coliform contamination was analyzed employing a one-way analysis of variance (ANOVA). Results indicated that the northern part of the lagoon exceeded recommended coliform thresholds for swimming (total coliform concentration (TCC) < 126 most probable number (MPN)) and seafood consumption (TCC < 100 MPN/g), indicating the presence of Escherichia coli. Water quality indices affirmed fecal pollution, except in the southern part of the lagoon. Furthermore, the study found high oyster consumption (76.7 %), elucidating that oysters from the northern part of Negombo Lagoon pose health risks.

Advancing ethnobiology for the ecological transition and a more inclusive and just world: a comprehensive framework for the next 20 years.

This opinion piece, written by ethnobiologists from different parts of the world, emphasizes the importance of ethnobiology research in advancing contemporary biology, natural resource management, biodiversity conservation, sustainable development, and, especially, contributing to the ecological transition and more just and inclusive world. To achieve these goals, it is essential to develop research and collaborate with social groups that live in close relationship with nature in research activities, such as Indigenous Peoples and Local Communities (IPLC), as well as Afro-descendants and other Marginalized, Minority or Minoritized Communities (AMMC). Ethnobiology can identify and provide locally appropriate solutions to local problems, enabling sustainable resource management at the landscape level. The text explores important aspects that need to be considered to guide the future of ethnobiology in the next 20 years, aiming to integrate and amplify previous discussions held in the discipline and identify points that demand ongoing attention. This paper highlights reflections from diverse researchers, emphasizing how ethnobiology can embrace different perspectives and employ rigorous analysis of complex phenomena toward effective policies and practices. This approach holds the potential to address the challenges the planet is currently facing in the coming decades.

Does mangrove vegetation structure reflect human utilization of ecosystem goods and services?

Many coastal communities in developing countries depend on mangrove ecosystem services (ES). A combination of anthropogenic and environmental stresses threatens mangroves globally. This study at the Ankobra catchment communities in Ghana focused on the relation between ES utilization and mangrove forest structure. Through vegetation survey, we observed significant effects of selective logging, branch cutting, density of Acrostichum aureum, and water stress on tree stocking and sapling densities. We observed through interviews in five communities that about 98% and 88% of mangrove wood harvested are used for fuelwood and construction respectively. The vegetation structure of the forest areas receiving high harvesting pressures was less complex, with lower tree and sapling density, as well as lower seed-bearing trees than less-disturbed areas. Existing mangrove harvesting regulations are compromised to accommodate the needs of the surrounding communities. Recognizing these impacts is important to improve management decisions, address community needs, and reduce pressure on mangroves.

Dataset of microplastics in the mangrove brachyuran crabs at Setiu Wetlands, Peninsular Malaysia.

The present dataset provides information on the abundance of microplastics (MPs) in relation to different feeding habits of the four mangrove brachyuran crab species namely, Parasesarma eumolpe, Austruca annulipes, Metaplax elegans and Scylla olivacea at Setiu Wetlands in Peninsular Malaysia. Three sites namely, Pulau Layat (upstream, close to the core mangrove zone), Kampung Pengkalan Gelap (midstream, close to the settlements), and Pulau Sutung (downstream, close to the shifted river mouth) were chosen for the sample collection (through hand catch method and traps) in both the dry (Feb-Mar 2021) and the wet (Dec 2021 - Jan 2022) seasons. The cardiac stomach of each crab was dissected, digested in potassium hydroxide and then filtered through a 1.6 µm pore size glass fibre filter using the vacuum pump. The abundance, type and colour of MPs per crab individual were determined under a stereomicroscope (Carl Zeiss Stemi 508, China) attached to the digital camera (Axiocam 208 colour). The general abundance of MPs was found in the order of carnivorous S. olivacea > microphytobenthos feeder A. annulipes > herbivorous P. eumolpe > detritivorous M. elegans. The data also reveal morphometric measurements such as body weight, gut weight, carapace width and carapace length of the crab specimens. The information given in this article is useful for study replications and scientific comparisons, especially with brachyuran crabs and other organisms with similar feeding guilds, in the mangroves of Malaysia and elsewhere.

Commercially important mangrove crabs are more susceptible to microplastic contamination than other brachyuran species.

Brachyuran crabs are ecologically and economically important macrofauna in mangrove habitats. However, they are exposed to various contaminants, including plastics, which bioaccumulate in relation to their feeding modes. Setiu Wetlands is a unique place on the east coast of Peninsular Malaysia where different ecosystems such as mangroves, lagoon, beaches, etc., are duly connected and influencing each other. In recent years, the shifted river mouth has threatened these wetlands, causing severe hydrodynamic changes in the lagoon, especially in the core mangrove zone. The present study tested microplastics (MPs) contamination in the mangroves through brachyuran crabs as indicators. Three sampling sites, namely Pulau Layat, Kampung Pengkalan Gelap, and Pulau Sutung were chosen. The four abundant crab species Parasesarma eumolpe, Metaplax elegans, Austruca annulipes, and Scylla olivacea, which display different feeding behaviours were collected from all sites covering the dry (Feb-Mar 2021) and the wet (Dec 2021-Jan 2022) seasonal periods. There were significant differences in the seasonal abundance of MPs among crab species. The highest accumulation of MPs in the crab stomachs in the dry season could be linked to subdued water circulation and poor material dispersion. Besides the lower MPs in the wet period due to improved water exchange conditions, its significant presence in the stomachs of S. olivacea indicates the role of its feeding behaviour as a carnivore. In addition, the micro-Fourier transform infrared spectroscopy (micro-FTIR) revealed the widespread occurrence of polymers such as rayon and polyester in all species across the sites. Given the fact that crabs like S. olivacea are commercially important and the ones contaminated with MPs can cause detrimental effects on the local community's health, further managerial actions are needed to assure sustainable management of the Setiu Wetlands.

Priority areas to protect mangroves and maximise ecosystem services.

Anthropogenic activities threaten global biodiversity and ecosystem services. Yet, area-based conservation efforts typically target biodiversity protection whilst minimising conflict with economic activities, failing to consider ecosystem services. Here we identify priority areas that maximise both the protection of mangrove biodiversity and their ecosystem services. We reveal that despite 13.5% of the mangrove distribution being currently strictly protected, all mangrove species are not adequately represented and many areas that provide disproportionally large ecosystem services are missed. Optimising the placement of future conservation efforts to protect 30% of global mangroves potentially safeguards an additional 16.3 billion USD of coastal property value, 6.1 million people, 1173.1 Tg C, and 50.7 million fisher days yr-1. Our findings suggest that there is a pressing need for including ecosystem services in protected area design and that strategic prioritisation and coordination of mangrove conservation could provide substantial benefits to human wellbeing.

A socio-ecological assessment aiming at improved forest resource management and sustainable ecotourism development in the mangroves of Tanbi Wetland National Park, The Gambia, West Africa.

Although mangroves dominated by Avicennia germinans and Rhizophora mangle are extending over 6000 ha in the Tanbi Wetland National Park (TWNP) (The Gambia), their importance for local populations (both peri-urban and urban) is not well documented. For the first time, this study evaluates the different mangrove resources in and around Banjul (i.e., timber, non-timber, edible, and ethnomedicinal products) and their utilization patterns, including the possibility of ecotourism development. The questionnaire-based results have indicated that more than 80% of peri-urban population rely on mangroves for timber and non-timber products and consider them as very important for their livelihoods. However, at the same time, urban households demonstrate limited knowledge on mangrove species and their ecological/economic benefits. Among others, fishing (including the oyster-Crassostrea cf. gasar collection) and tourism are the major income-generating activities found in the TWNP. The age-old practices of agriculture in some parts of the TWNP are due to scarcity of land available for agriculture, increased family size, and alternative sources of income. The recent focus on ecotourism (i.e., boardwalk construction inside the mangroves near Banjul city) received a positive response from the local stakeholders (i.e., users, government, and non-government organizations), with their appropriate roles in sharing the revenue, rights, and responsibilities of this project. Though the guidelines for conservation and management of the TWNP seem to be compatible, the harmony between local people and sustainable resource utilization should be ascertained.

Integrating local ecological knowledge and management practices of an isolated semi-arid papyrus swamp (Loboi, Kenya) into a wider conservation framework.

The current study documented local utilization of Cyperus papyrus L. (papyrus), harvesting patterns, threats, and local management practices among the Endorois community living around Loboi swamp (Kenya). Papyrus is a highly productive freshwater macrophyte that is widely utilized throughout tropical Africa. However, increased human population and poverty, has led to over exploitation and conversion of papyrus wetlands to agricultural fields. Nonetheless, users of papyrus hold important local ecological knowledge (LEK) and practices. We show that Endorois practices on papyrus uses are compatible with the management priorities of the swamp and a wider conservation framework using data obtained from three focus group discussions (FGD), interviews of 34 households and 15 key informants. The study revealed that papyrus support local livelihood notably as a source of income (papyrus mats are sold), cattle fodder, roofing materials (shelter), and cooking fuel. The study further revealed important LEK relating to harvesting patterns, recovery after harvesting and traditional management practices. Correlation and principal component analyses showed that experienced old harvesters (EXPERT) avoided harvesting repeatedly at the same location (REVISIT), thereby allowing recovery of papyrus when compared to younger harvesters (r = 0.63, p < 0.01). However, over 70% of harvesters predicted a decrease in papyrus coverage in the future due to the current diversion of water from the swamp, and frequent droughts, despite the instituted traditional management strategies (e.g. rotational harvesting) to curb overharvesting. The study concluded that the documentation of site-scale papyrus users' profile, LEK, and traditional practices are vital for the conservation and management of Loboi swamp.

Understanding interdisciplinary perspectives of plant intelligence: Is it a matter of science, language, or subjectivity?

BACKGROUND: Evidence suggests that plants can behave intelligently by exhibiting the ability to learn, make associations between environmental cues, engage in complex decisions about resource acquisition, memorize, and adapt in flexible ways. However, plant intelligence is a disputed concept in the scientific community. Reasons for lack of consensus can be traced back to the history of Western philosophy, interpretation of terminology, and due to plants lacking neurons and a central nervous system. Plant intelligence thus constitutes a novel paradigm in the plant sciences. Therefore, the perspectives of scientists in plant-related disciplines need to be investigated in order to gain insight into the current state and future development of this concept. METHODS: This study analyzed opinions of plant intelligence held by scientists from different plant-related disciplines, including ethnobiology and other biological sciences, through an online questionnaire. RESULTS: Our findings show that respondents' personal belief systems and the frequency of taking into account other types of knowledge, such as traditional knowledge, in their own field(s) of study, were associated with their opinions of plant intelligence. Meanwhile, respondents' professional expertise, background (discipline), or familiarity with evidence provided on plant intelligence did not affect their opinions. CONCLUSIONS: This study emphasizes the influential role of scientists' own subjective beliefs. In response, two approaches could facilitate transdisciplinary understanding among scientists: (1) effective communication designed to foster change in agreement based on presented information; and (2) holding space for an interdisciplinary dialogue where scientists can express their own subjectivities and open new opportunities for collaboration.

From bathymetry to bioshields: a review of post-tsunami ecological research in India and its implications for policy.

More than half a decade has passed since the December 26th 2004 tsunami hit the Indian coast leaving a trail of ecological, economic and human destruction in its wake. We reviewed the coastal ecological research carried out in India in the light of the tsunami. In addition, we also briefly reviewed the ecological research in other tsunami affected countries in Asia namely Sri Lanka, Indonesia, Thailand and Maldives in order to provide a broader perspective of ecological research after tsunami. A basic search in ISI Web of Knowledge using keywords "tsunami" and "India" resulted in 127 peer reviewed journal articles, of which 39 articles were pertaining to ecological sciences. In comparison, Sri Lanka, Indonesia, Thailand and Maldives had, respectively, eight, four, 21 and two articles pertaining to ecology. In India, bioshields received the major share of scientific interest (14 out of 39) while only one study (each) was dedicated to corals, seagrasses, seaweeds and meiofauna, pointing to the paucity of research attention dedicated to these critical ecosystems. We noted that very few interdisciplinary studies looked at linkages between pure/applied sciences and the social sciences in India. In addition, there appears to be little correlation between the limited research that was done and its influence on policy in India. This review points to gap areas in ecological research in India and highlights the lessons learnt from research in other tsunami-affected countries. It also provides guidance on the links between science and policy that are required for effective coastal zone management.

A dataset of tree heights in mangrove and non-mangrove trees in Malaysia derived from multiple measurement methods.

The dataset contains tree height data collected in 200 mangrove and non-mangrove trees sampled in various sites in Malaysia. Different height measurement methods were performed, including visual measurements (stick, thumb rule) and precision field instruments (clinometer, laser rangefinder and altimeter), which were compared against benchmark values obtained using an unmanned aerial vehicle (UAV) and a Leica distometer. The core data have been analysed and interpreted in the paper by Saliu et al. ''An accuracy analysis of mangrove tree height mensuration using forestry techniques, hypsometers and UAVs '' [1], in which the accuracy of each method for tree height measurement was discussed.

Mercury concentration data from Matang Mangrove Forest Reserve, Malaysia.

This paper presents the results of mercury analysis on 786 abiotic (surface sediments) and biotic (plant and animal tissues) samples collected from 10 sites at Matang Mangrove Forest Reserve in Peninsular Malaysia. Sediment samples were collected at the surface level from both river bank and forest understory. Whereas plant tissues obtained from Rhizophora apiculata Blume and Rhizophora mucronata L. consisted of leaves (in four stages namely young, mature, senescent and decomposing), bark and roots (divided into xylem, cortex and epidermis), the animal samples were represented by muscle tissue of the gastropod Cassidula aurisfelis Bruguière and the cockle Tegillarca granosa L. The mercury concentration measurements were obtained through a cold vapor atomic absorption spectrometer. The core data have been analysed and interpreted in the paper "Distribution of mercury in sediments, plant and animal tissues in Matang Mangrove Forest Reserve, Malaysia" [1].

Distribution of mercury in sediments, plant and animal tissues in Matang Mangrove Forest Reserve, Malaysia.

Charcoal production activities at the Matang Mangrove Forest Reserve (MMFR) in Peninsular Malaysia have a potential to emit volatile compounds such as Hg back into the ambient environment, raising concerns on the public health and safety. The present study was aimed at analyzing Hg concentration from different plant/animal tissues and sediment samples (in total 786 samples) to understand clearly the Hg distribution at the MMFR. Leaves of Rhizophora spp. showed higher Hg concentration with an increasing trend from young, to mature, to senescent and decomposing stages, which was possibly due to accumulation of Hg over time. The low Hg concentration in Rhizophora roots and bark suggests a limited absorption from the sediments and a meagre accumulation/partitioning by the plant tissue, respectively. In the case of mangrove cockles the concentration of Hg was lower than the permissible limits for seafood consumption. Although the mangrove gastropod - Cassidula aurisfelis Bruguière had rather elevated Hg in the muscle tissue, it is still less than the environmental safely limit. Beside the chances of atmospheric deposition for Hg, the sediment samples were found to be unpolluted in nature, indicating that in general the MMFR is still safe in terms of Hg pollution.