Mangroves are trees and shrubs that grow in the intertidal areas of tropical and subtropical coasts (Spalding et al., 2010; Duke, 2017) covering about 136,000 km² in 108 countries (Spalding and Leal, 2021). They occur in all continents except Europe and Antarctica, with the largest extent found in Asia (39%), followed by Africa (20%), North and Central America (15%), South America (14%) and Oceania (12%) (Spalding and Leal, 2021). The largest contiguous mangrove forests include the Sundarbans (India and Bangladesh), the Niger Delta (Nigeria), the coastlines of Northern Brazil and the Southern Papua, which together comprise 16.5% of the world's mangrove forests (Spalding et al., 2010). Mangrove distribution falls into two biogeographical regions, the Indo-West Pacific (IWP) and Atlantic East Pacific (AEP). The IWP includes the mangroves of East Africa, Asia, and Australia while the AEP constitutes the mangroves of West Africa, East, and West America (Alongi, 2002). There are 73 mangrove species globally, the IWP region is the most diverse with 62 species whereas AEP has 12 species with one common species (Auchrosticum Aureum) (Spalding et al., 2010). Species richness decrease from 30 species in South East Asia to about <10 species in West Africa and the Americas (Duke, 2017).

The distribution of mangroves is strongly influenced by geomorphic and climatic drivers (e.g., temperature and moisture) (Alongi, 2002; Njiru et al., 2022) and exposure to low temperatures is a key constraint. Warming temperatures are enabling mangroves to expand poleward (Giri and Long, 2016; Coldren et al., 2019; Cohen et al., 2020) and landward (Lucas et al., 2018; Visschers et al., 2022) as tidal incursion progresses with rising sea levels. While mangroves are expanding into saltmarsh ecotones, there is a net loss of mangroves globally (Goldberg et al., 2020; Hagger et al., 2022) due to the effects of major storms (Sippo et al., 2018; Lagomasino et al., 2021) and human pressures (Goldberg et al., 2020). Mangrove loss affects the provision of ecosystem services (ES) that directly support millions of livelihoods, particularly in the Global South (Malik et al., 2017; Nyangoko et al., 2022).

Mangroves provide a wide variety of ES (Walters et al., 2008; Donato et al., 2011; Lee et al., 2014; Mukherjee et al., 2014). They are carbon-rich ecosystems (Donato et al., 2011; Alongi, 2020), that support fisheries (zu Ermgassen et al., 2020), provide shoreline protection (Barbier et al., 2011; Barbier, 2020), and wood and non-wood resources to coastal communities (Lee et al., 2014). The concept of ES has created an effective bridge between ecological and economic approaches, challenging the established views about the “value” of nature and the long-lasting and wider economic impacts of resource degradation (Costanza et al., 2017; Cifuentes, 2021). In the context of this paper, ES refer to all services and benefits offered by mangroves to people, while mangrove use focuses on the direct use/provisioning services.

Studies have attempted to review several aspects of mangrove ES including disservices (Friess, 2016). Most reviews focus on the valuation of mangrove ES at a local scale (Himes-Cornell et al., 2018; Barbier, 2020; Getzner and Islam, 2020; Afonso et al., 2022) or on specific types, e.g. cultural services (Moore et al., 2022). There is a paucity of evidence on how the utilization of mangrove resources varies globally, despite evidence of the rate of change in mangrove cover being influenced by use (Sasmito et al., 2019; Goldberg et al., 2020). Understanding these global utilization patterns is important for developing effective conservation strategies and ensuring sustainable use of mangrove ecosystems. Hence, this systematic review aimed to provide a comprehensive overview of the current state of knowledge on mangrove resource utilization, focusing on the coverage of ecosystem services (ES), the geographical distribution of studies, and the types of uses identified globally. To achieve these aims, the objectives of this review are to: (a) identify the range and frequency of different ES covered in the literature and determine knowledge gaps; (b) map the global distribution of studies and evaluate regional differences; and (c) categorize and compare uses (e.g., timber, fisheries, tourism) studied in different regions.

A systematic review was undertaken following the methods of previous studies (e.g., Berrang-Ford et al., 2011; Xu et al., 2019). The search was conducted in March 2023 on the Web of Science (WoS), as this database is widely used and covers interdisciplinary peer-reviewed literature published since 1900 (Jacsó, 2005). No papers published after March 2023 were included in the review. The search criteria were:

Indexes = SCI-EXPANDED, SSCI, A&HCI, CPCI-S, CPCI-SSH, ESCI

Timespan = All years (1900 to March 2023)

Language: English

Document types: Article OR Book Chapter OR Proceedings Paper OR Review

Topic search (TS) within the title, author keywords, Keywords Plus^® or abstract:

The search yielded a total of 3,238 articles. The titles, authors' keywords, and abstracts of these articles were exported to Excel. A keyword search was done on the Excel file to identify which papers mentioned the different services (using the search function and the results were exported to a different Excel sheet) (Figure 1). Titles and abstracts were screened, and articles covering experimental/isotope analysis, analysis of the physicochemical composition, mangrove mapping, genetics studies, or other studies not focusing on mangrove use or ES were excluded. Supplementary material 1 provides the justification for exclusion of articles. A total of 310 articles were retained for full-text reading and extraction of information (Table 1) and were categorized based on the main ES covered. If the paper mentioned one service, but the focus was on another, the paper was moved to the relevant category, which was the basis for the geographical analysis.

The earliest paper included in the analysis was published in 1993 and the number of publications covering mangrove ES increased over time, with the highest numbers published in 2018 (16%) and 2019 (13%) (Figure 2).

A literature review produced by Friess (2016) showed that, between 1823 and 1883, studies focused on the export of mangrove products, although regulation services, such as erosion control and sediment accretion, were recognized as early as 1865. Studies on regulating and supporting services (e.g., fisheries, habitat, coastal protection and carbon sequestration) have dominated publications on mangrove ES since 2015, with peak number of articles in 2018 and 2019. Ongoing global attention on climate change and mitigation mechanisms in the Paris Agreement 2015 and the subsequent COP conferences have stimulated research on the contribution of blue carbon e.g., in carbon sequestration (e.g., Taillardat et al., 2018; Serrano et al., 2019; Were et al., 2019; Chatting et al., 2022) and natural coastal protection (Morris et al., 2018; Vanegas et al., 2019; Asari et al., 2021; Chang and Mori, 2021). Furthermore, regulating and supporting services have direct economic value (fisheries) or global significance (carbon storage, biodiversity), making them priorities for research funding and policy attention.

The review of 310 articles indicates that uses of mangrove resources are similar across continents, despite local variations in the dominant types and intensity of uses (e.g., Hamza et al., 2023; Reyes-Arroyo et al., 2021; Cornejo et al., 2005). Therefore, knowledge gained from research on ES/uses in one region can be replicable in another. It is unsurprising that the largest number of papers (43%) cover mangrove ES and use in Asia, where 39.2% of the global mangrove coverage is found. Indonesia alone has 19.7% of the world's mangrove cover (Jia et al., 2023) and was the country with the most literature on mangrove uses/ES in Asia (26% of the papers analyzed in Asia) and the world (11% of 310 papers). Despite the similarity of mangrove use across continents, the noted absence of published studies covering the ES of coastal protection in South America and waste management in Africa highlights regional disparities in mangrove ES research.

In 2020, Brazil and Australia ranked second and third in the world's mangrove coverage respectively (Jia et al., 2023) and this is reflected in the relative high number of papers on mangrove ES. Despite 20 papers found with information of mangrove ES in Australia, none covered direct use. This is surprising considering that traditional use of mangroves by indigenous people of Australia are wide and varied, including all the uses identified in this review (firewood and charcoal; construction of houses, furniture, boats and fishing gear; tannins for dyeing and leather production, food, medicine) and others, such as insecticide (Bandaranayake, 1998). Although information on uses of mangroves in Australia can be found in online and gray literature, they are scarce in scientific publications. Perhaps there is less research interest because traditional uses of mangroves in Australia are no longer common practice and restricted to remote areas of low population, hence low environmental impact (Bird, 1986).

It is worth noting that the search did not capture all papers that might be considered relevant, such as the review of traditional and medicinal uses of mangroves written by Bandaranayake (1998) and Rasquinha and Mishra (2021). Bandaranayake (1998) cites Walsh (1977), who described the use of Rhizophora sp. seedlings to cure sore mouth and to produce wine that had aphrodisiac effect since the 13th century in Arabia as the earliest historical reference to the medicinal use of mangroves. It is important to recognize that a systematic search for scientific literature may miss some interesting publications and information, even when comprehensive databases such as the WoS are used. Use of different terms or phrases for the same concept or publishing in less prominent journals or gray literature that are not indexed are some of the reasons.

North America was the second most covered region having 16% of all the literature analyzed despite being third in terms of mangrove coverage (Spalding and Leal, 2021). Most of the literature on study areas in North America covered regulating and supporting services, while in Asia and Africa research on provisioning/direct uses of mangroves dominate the literature. Mangroves support the livelihoods of coastal communities in lower-income countries and their direct use is linked to mangrove loss and degradation, thus understanding their use is relevant to resource management (Feurer et al., 2018; Das et al., 2022). The proportion of literature covering the utilization of wood for fuel and construction was highest in Africa, depicting a greater dependence on mangrove wood products in this region compared to others (Spalding and Leal, 2021; Nunoo and Agyekumhene, 2022). The use of mangrove wood for domestic fuel is widespread across the continent, while commercial uses such as fish smoking in Cameroon and lime production in Madagascar are also notable. This heavy reliance on wood resources raises concerns about the sustainability of mangrove ecosystems, especially in West-Central African coastal states. The historical use of mangroves as a source of medicine, food and fodder was better represented in literature from Asia and Africa than in other regions.

This review identified 11 types of ES (Table 1) that were more often mentioned in the literature and should not be considered as the only uses and ES provided by mangroves. Other studies might have identified different number and types of mangrove ES depending on how the services are grouped, the terminology used and the geographic scale and focus of the research. For example, obtaining food for humans and feeds for animals were considered separate services in other studies (e.g., in Rönnbäck et al., 2007), while here they were counted together (e.g., Table 1, Figure 2). While genetic resources and maintenance of soil nutrients are more likely to be elicited by experts (e.g., Himes-Cornell et al., 2018), research focused on local community perceptions identify site-specific ES, such as space for the disposal of household waste, hunting, urban development (e.g., Jadin and Rousseau, 2022).

Communities living on tropical and subtropical coasts worldwide have used and relied on mangrove wood for their needs for thousands of years (e.g., Robinson and McKillop, 2013). Mangrove wood is appreciated due to high durability, resistance to salinity (Walters et al., 2008) and termite attacks (Conchedda et al., 2011). Due to the quality of the resource and its availability are an attraction, the risk of overexploitation is far greater in locations within few kilometers from settlements and of easier access, such as forest edges, around trails and roads or accessible by boat (Rasquinha and Mishra, 2021). While clearing mangroves for aquaculture continues, especially in Southeast Asia (Goldberg et al., 2020), harvesting pressures have decreased in some areas due to voluntary practice changes or enforced regulations. Examples are provided here; however, reports on changes in mangrove use over time are scarce in the scientific literature, and the underlying drivers are rarely discussed. It is apparent that the use of mangrove wood in construction of houses and boats is decreasing or no longer practiced by some communities in Madagascar (Scales and Friess, 2019), Brazil (Moreira dos Santos and Lana, 2017), India (Rasquinha and Mishra, 2021) and others. Rasquinha and Mishra (2021) report that communities living within the Bhitarkanika Wildlife Sanctuary on the east coast of India now use materials brought from nearby cities for their construction needs but they do not explain why mangrove wood is no longer used. They emphasize that local communities still depend on mangroves for fuelwood (cooking and heating), harvesting dry wood and cutting branches of preferred species while preserving larger trees. Legal protection of mangrove forests was a driver for the reduction in harvest and use of mangrove wood in southern Brazil, although illegal cutting is still practiced by locals who cannot afford alternative products (Moreira dos Santos and Lana, 2017). Legislation and regulations to halt mangrove loss and degradation were also implemented in other countries, such as the Philippines (Janssen and Padilla, 1999) and Kenya (GoK, 2017). However, illegal harvesting still occurs if suitable and sustainable alternative sources of income are not available to local communities (Hamza et al., 2023).

While in some places traditional uses of natural resources are gradually giving way to practices that use alternative products when they become affordable (Hamza, 2022), in other cases, increasing local needs for subsistence or income perpetuate the dependence on mangroves. Scales and Friess (2019) describe traditional and emerging uses of mangrove wood by communities in the Bay of Assassins in southwestern Madagascar for subsistence and commercial purposes that increase pressures on this natural resource. They report that houses and fences are almost exclusively built with mangrove wood, and more recently, mangrove poles are used for seaweed aquaculture and in the construction and operation of lime kilns. Paradoxically, the income from aquaculture (an activity that uses mangrove wood) has increased the demand for lime rendering, as it strengthens houses against the impacts of cyclones and is seen as an indicator of status (Scales and Friess, 2019). Contrasting with other locations in Africa, the Malagasy community in the Bay of Assassins prefer and mostly use wood from terrestrial forests as fuelwood for domestic cooking (Scales and Friess, 2019).

Thiagarajah et al. (2015) suggest that many communities in Asia had a closer connection with nature in the past and had a greater appreciation of the intrinsic value of mangroves before coastal areas became intensely developed. Although this might be common in other coastal areas worldwide, the intrinsic value of mangroves and how perceptions might have changed through time are not well described or assessed in the scientific literature available in English. Cultural ES associated with the intangible value of mangroves, such as sense of place, inspiration, and cultural heritage, are understudied in all regions and only covered in 9% of the literature analyzed. Similarly, a global review by Bimrah et al. (2022) mostly identified studies on regulatory services, such as carbon sequestration and disaster risk reduction, while cultural services were the least represented. Cultural services are more difficult to identify as they are innate to specific sites and individual experiences and, therefore, cannot be assessed through simple benefit transfer methods. Understanding the direct uses of mangrove resources by surrounding communities and their basic needs is essential for policy and management measures to be effective and sustainable. However, the management of natural resources will only be inclusive and equitable when their intangible cultural values are fully appreciated and considered.

A systematic review of 310 papers in the WoS focusing on mangrove uses has shown that mangrove ecosystems provide a wide range of ecosystem services globally, but their importance and utilization vary significantly across regions. While some services like fisheries support, carbon storage, and habitat provision are universally recognized, others show distinct regional patterns. The emphasis on certain ecosystem services in specific regions likely reflects local socio-economic dependencies and cultural values. Direct use of mangrove resources (e.g., wood for fuel and construction) are most often covered in less developed regions, such as Asia, Africa and South America. While the use of mangrove wood for fuel is still pervasive in less developed countries, the use in construction is reducing in some areas. The information presented also reveals a tension between the intensive use of mangrove resources (particularly for wood and charcoal) and the need for conservation. However, a shift is observed in the use of mangrove wood, transitioning from a primary source of income to subsistence use in Asia, Africa, and South America.

Beyond their ecological functions, mangroves provide significant value by supporting livelihoods, cultural practices, and traditional knowledge systems. Notably, mangroves possess medicinal properties, yet such uses remain underutilized globally. Furthermore, cultural services, which are essential for inclusive and equitable conservation, were found to be underrepresented in the literature. Therefore, it is crucial to emphasize these values in conservation efforts. The findings underscore the need for context-specific conservation and management approaches that consider both the ecological importance of mangroves and their socio-economic value to local communities, ensuring a more holistic and effective conservation strategy.

The literature coverage might not be a fair reflection of pressing issues as funding availability, distance from research centers and/or language barriers can create bias (in geography or topic coverage). This paper only reviewed literature from WoS and may have missed some relevant literature that might have been obtained if the search was extended to other databases. In addition, the review covers only scientific papers published in English, which tend to reflect wider/international interests, while gray literature in local language might offer different insights into local uses.