Unravelling the impact of environmental variability on mangrove sediment carbon dynamics.

Mangrove ecosystems represent low-cost climate-regulating systems through carbon storage in their sediments. However, considering the complex shifts in shallow coastal ecosystems, it is clear from just a few sets of environmental impacts on their carbon storage that there is a deficit in the information required for preserving this service. Here, we investigated the spatial and temporal variability of hydrographic factors (water temperature, pH, salinity, dissolved oxygen (DO), flow velocity, turbidity) and sediment characteristics (sedimentation rate and sediment grain size) on the intricate carbon dynamics of mangroves by examining which key variable(s) control mangrove sediment organic matter (OM). We used in-situ monitoring to assess the hydrographic dynamics, sedimentation rate, sediment organic content, and granulometry. Laboratory loss-on-ignition and granulometric methods were employed to quantify OM in trapped and bottom sediments and sediment grain size, respectively. Based on the findings, water pH, salinity, and DO were the key regulators of OM in sediments. Despite conventional expectations, the study observed positive effects of DO on OM, highlighting the possible role of aquatic plant photosynthesis and freshwater inflow. Sedimentation rates, usually considered crucial for OM accumulation, showed no significant relationship, emphasizing the importance of sediment content over quantity. Noteworthy findings include the role of sediment grain size in OM storage within mangrove sediments. Even though the grain size class of 63 µm diameter had the highest mean weight across the studied sites, there were significant positive correlations between Trap and Bottom OM with 500 and 2000 µm grain size classes, emphasizing the need to consider sediment characteristics in carbon dynamics assessments. Overall, this research provides valuable insights into the intricate environmental dynamics of mangrove ecosystems that are crucial to understanding and managing these vital coastal habitats.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Mangroves give cause for conservation optimism, for now.

Friess et al. discuss the results of conservation efforts for mangrove forests in recent years.

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.

Infestation mechanisms of two woodborer species in the mangrove Sonneratia alba J. Smith in Kenya and co-occurring endophytic fungi.

Insect damage on trees can severely affect the quality of timber, reduce the fecundity of the host and render it susceptible to fungal infestation and disease. Such pathology weakens or eventually kills the host. Infestation by two insect woodborer species (a moth and a beetle) is causing mortality of Sonneratia alba, a wide-ranging pioneer mangrove species of the Indo-Pacific. Establishing the infestation mechanism of the two insect woodborer species is an initial and essential step towards understanding their ecological role in the mangroves and in determining sustainable management priorities and options. Our main objectives were to investigate the infestation mechanism employed by the two insect woodborers which infest S. alba trees, to establish the occurrence of secondary infestation by endophytic fungi in the infested S. alba branches, and to explore a control management option to the woodborer infestation. We conducted an external inspection of infested branches in two large embayments in Kenya, Gazi Bay and Mida Creek, and by splitting infested branches we determined the respective internal infestation mechanisms. Infested wood samples from Gazi Bay and Mida Creek were incubated at 28±1°C for 3-5 days to establish the presence of fungi. A survey was conducted in both Gazi Bay and Mida Creek to ascertain the presence of ants on S. alba. The infestation characteristics of the two insect woodborer species were different. It took 6-8 months for the beetle to kill a branch of 150 cm-200 cm long. For the moth to kill a branch, it depended upon several factors including the contribution by multiple species, other than the moth infestation alone. A total of 15 endophytic fungal species were identified. Two ant species Oecophylla longipoda and a Pheidole sp. inhabited 62% and 69% respectively of sampled S. alba trees in Gazi Bay whereas only Pheidole sp. inhabited 17% of the sampled S. alba trees in Mida Creek. In summary, we have documented the time it takes each woodborer species to kill a branch, the infestation mechanism of the two insect woodborers, and we hypothesized on the role of two ant species. The presence of several different fungal species was ascertained, and we discussed their possible role in the infested wood. Our results cannot unambiguously associate the woodborers and identified fungi. We recommend further studies to investigate the presence or absence, and if present, the nature of fungi in the gut of the woodborers.

A general framework for propagule dispersal in mangroves.

Dispersal allows species to shift their distributions in response to changing climate conditions. As a result, dispersal is considered a key process contributing to a species' long-term persistence. For many passive dispersers, fluid dynamics of wind and water fuel these movements and different species have developed remarkable adaptations for utilizing this energy to reach and colonize suitable habitats. The seafaring propagules (fruits and seeds) of mangroves represent an excellent example of such passive dispersal. Mangroves are halophytic woody plants that grow in the intertidal zones along tropical and subtropical shorelines and produce hydrochorous propagules with high dispersal potential. This results in exceptionally large coastal ranges across vast expanses of ocean and allows species to shift geographically and track the conditions to which they are adapted. This is particularly relevant given the challenges presented by rapid sea-level rise, higher frequency and intensity of storms, and changes in regional precipitation and temperature regimes. However, despite its importance, the underlying drivers of mangrove dispersal have typically been studied in isolation, and a conceptual synthesis of mangrove oceanic dispersal across spatial scales is lacking. Here, we review current knowledge on mangrove propagule dispersal across the various stages of the dispersal process. Using a general framework, we outline the mechanisms and ecological processes that are known to modulate the spatial patterns of mangrove dispersal. We show that important dispersal factors remain understudied and that adequate empirical data on the determinants of dispersal are missing for most mangrove species. This review particularly aims to provide a baseline for developing future research agendas and field campaigns, filling current knowledge gaps and increasing our understanding of the processes that shape global mangrove distributions.