Abstract
Purpose
Mangrove forests are one of the most bio-diverse and productive wetland environments on earth. However, these unique tropical forest environments that occupy coastal areas are among the most threatened habitats globally. These threats include logging, conversion of land for agriculture and mariculture and degradation due to pollution over the past 50 years. The large population of resilient mangroves occupying the Turneffe Atoll area in Belize faces growing anthropogenic threats such as permanent clearing of land for housing, infrastructural development and pollution and natural factors (climate change). Given the few formal studies done to evaluate mangrove resilience at Turneffe Atoll, the purpose of this study was to evaluate mangrove resilience and nursery functions in the Turneffe Atoll Marine Reserve (TAMR).
Design/methodology/approach
Mangrove fish abundance and forest structure was assessed by means of a visual census and the point-centred quarter method (PCQM) for 11 sites that span across conservation and general use zones.
Findings
This study found that the more resilient mangroves (lower vulnerability ranks, higher standing biomass and higher fish biomass and abundance) exist in general use zones and warrant the need for improved mangrove conservation measures for these areas by Turneffe Atoll Sustainability Association (TASA).
Research limitations/implications
Limitations of the methods for data collection included accessibility within mangrove forests stands when establishing PCQM, observer bias among data collectors, sites without surrounding mangroves were not captured to serve as a true control group and poor visibility underwater affected the estimation of fish species and size. The timeline for this research was only three months based on available funding, and no follow-up study was done to make a true comparison.
Originality/value
The findings of this research have a guiding role in the formulation of conservation measures such as better waste management, a robust framework for mangrove management, a communication strategy to guide public awareness and long-term monitoring surveys.
Keywords
Citation
Osborne, C.C., Cho-Ricketts, L. and Salazar, J. (2024), "The relationship between resilient mangroves and fish populations in the largest marine reserve in Belize: a case for conservation", Marine Economics and Management, Vol. 7 No. 2, pp. 159-180. https://doi.org/10.1108/MAEM-04-2024-0007
Publisher
:Emerald Publishing Limited
Copyright © 2024, Chetwynd Carlos Osborne, Leandra Cho-Ricketts and Jané Salazar
License
Published in Marine Economics and Management. Published by Emerald Publishing Limited. This article is published under the Creative Commons Attribution (CC BY 4.0) licence. Anyone may reproduce, distribute, translate and create derivative works of this article (for both commercial and non-commercial purposes), subject to full attribution to the original publication and authors. The full terms of this licence may be seen at http://creativecommons.org/licences/by/4.0/legalcode
1. Introduction
Mangroves are classified as small evergreen trees that thrive in intertidal zones of estuaries, lagoons and river deltas and dominate subtropical and tropical coastal systems (Singh, 2020). The productive nature and location of mangroves in nearshore, warm coastal waters, make them increasingly valuable targets for farming, mariculture and recreation. These activities fundamentally alter the physicochemical nature of the habitat, affecting animals such as shrimps, crabs and fishes that depend on these ecosystems for food and shelter (Jaxion-Harm, 2010; McSherry et al., 2023). Habitat destruction of coastal mangroves through sea level rise by means of climate change and deforestation by means of anthropogenic activities can alter niche dynamics in these communities (Seddon et al., 2011; Roy et al., 2023). Mangrove forests are declining globally due to anthropogenic and natural deforestation, which has resulted in the loss of one-third of mangrove forests and associated ecosystem services worldwide over the past 50 years (Gouvêa et al., 2022). Mangrove forests are important for the sustenance of fishes and invertebrates; providing coastal populations with protein sources and supporting livelihoods; shoreline protection against floods, tsunamis and typhoons; purification of water; absorption of pollutants; offsetting greenhouse gas emissions and sequestering carbon and provision of nursery habitats for fishes (McSherry et al., 2023; Rull, 2023). Additionally, these vital ecological goods and services have the potential to improve mangrove resilience to climate change, storms, sea level rise and anthropogenic activities (Turschwell et al., 2020; Gouvêa et al., 2022).
The most common variable used to illustrate mangrove species zonation patterns is tidal inundation frequency (Ma et al., 2020; Sreelekshmi et al., 2020). Mangrove species zonation in Belize adheres to the pattern of Rhizophora typically encountered near the shoreline and inundated areas, while Avicennia are frequent in drier areas that are further inland and have higher soil salinities due to evaporation (Murray et al., 2003; Piou et al., 2006; Cherrington et al., 2020). Classifying mangroves into different types provides critical information about the forest structure and facilitates the prioritisation of conservation efforts. Mangrove seedlings are individual trees <1.37 m tall, and the presence of mangrove seedlings gives an indication of the level of recruitment in a particular area (Kauffman and Donato, 2012; Ellison, 2015). Saplings are trees with a diameter at breast height (DBH) <2.5 cm, while overstory trees are defined by DBH >5 cm (Almada-Villela et al., 2003; Trettin et al., 2015). Relatively high growth rates are characteristic features of mangrove saplings and seedlings, and these mangrove types are capable of colonising newly created intertidal substrates and forest gaps (Numbere, 2021; Quadros et al., 2021). Dwarf mangroves are trees typically <3 m tall, which are constituted by scrub categories and typically occupy areas where the environmental conditions are extreme and the vegetation is restricted to short mangroves (Romero-Mujalli and Melendez, 2023). Medium mangroves are trees approximately 3–10 m tall which thrive in locations inland that are densely populated by fringing R. mangle, which grow in exposed sites along the coast and on cays (Kauffman et al., 2020). Tall mangroves are trees with a mean height >10 m tall, which are typically restricted to locations on the margin of rivers and estuaries that are elevated on the largest cays where the required combination of restricted salinity, high levels of sustained nutrients and stable substrate exist to sustain this stand of large trees (Kauffman et al., 2020). Standing biomass gives an indication of the quantity of standing organic matter per unit area at a particular time (Thivakaran et al., 2020). The quantity of standing biomass stored in a forest is a function of this ecosystem age, productivity, exportation strategies and organic matter allocation (Thivakaran et al., 2020).
Mangrove ecosystems play a vital role in the Belize Barrier Reef Complex owing to the support provided for animals, from fishes to crustaceans, as well as sustaining high levels of primary production centred around the production of leaf litter, which provides a trophic subsidy for adjacent coastal waters, both near and far (Dharanirajan et al., 2010; Cherrington et al., 2020). Mangrove resilience refers to a measure of the persistence of mangrove ecosystems and of their ability to absorb change and disturbance and still maintain the same relationships between populations (Seddon et al., 2011; Ellison et al., 2020). Further, mangroves possess considerable resilience to sea level fluctuations owing to their ability to actively modify their environment by changing processes of surface elevation and their migration ability to inland zones over consecutive generations (Ward et al., 2016). This sort of migration to landward zones allows the mangrove ecosystem to absorb and recognise the effects of the stress and facilitates the maintenance of its processes, structures and functions (Numbere, 2021; Rull, 2023). Studies conducted across the Caribbean reported that mangrove species zones migrated inland where a preferred frequency of inundation, depth and period existed, since these mangroves were incapable of keeping pace with relative sea level rise (Rull, 2023). This gives an indication of the mangroves' ability to adapt to changes in sea level and remain resilient.
Mangroves exhibit high resilience subsequent to disturbances due to their pioneering species ability, high productivity and natural regeneration capabilities (Capote-Fuentes, 2007; Ellison et al., 2020). For instance, mangroves quickly re-grow subsequent to hurricanes (a disaster that Belize is prone to) and floods, but changes in temperature, hydrologic fluxes, topography and sedimentation affect mangrove forests (Rull, 2023). In the Caribbean region, hurricanes are one of the most destructive natural hazards affecting mangroves, and their occurrence has increased over the years (Rull, 2023). Certain areas of the Caribbean region with high mangrove density such as Cuba are particularly vulnerable to hurricanes compared with the South American region, which is rarely affected. Despite these disturbances, mangroves show relatively high resilience to hurricane activity and natural regeneration is common (Rull, 2023).
Mangroves’ complex structure forms aquatic vegetation that provides feeding grounds and shelter for small predators and prey (Nagelkerken, 2009; Nagelkerken et al., 2010; DeYoe et al., 2020). For instance, in the Caribbean, there is a high abundance and diversity of estuarine, coral reef, invertebrates and juvenile fishes that shelter in mangroves, which are structure-rich habitats (Nagelkerken et al., 2010; DeYoe et al., 2020). High abundances of juvenile fishes in mangroves are based on these proposed hypotheses: (a) isolated location of these biotypes from off-shore waters or coral reefs and thus fewer encounters with predators; (b) copious amounts of food are provided by these biotypes for fishes, (c) predators' efficiency to forage is reduced by the relatively turbid water of the estuaries and bays and (d) extensive areas are covered by these biotopes and planktonic fish larvae may be intercepted more effectively (Nagelkerken et al., 2000; DeYoe et al., 2020). These hypotheses support the features of resilient mangroves, which provide nursery habitats for juvenile fishes that serve as a protein source for the Belizean population; hence, there is a need for further protection of these mangroves at Turneffe Atoll to safeguard this valuable ecosystem service.
Belize still retains large areas of mangroves (especially Turneffe Atoll, where two-thirds of the atoll’s land area is occupied by mangroves) compared to many neighbouring countries due to the small population, which reduces developmental pressures and the concentration of the population in a single centre (i.e. Belize City) (Cherrington et al., 2020). This relatively large area of mangroves should not be treated with complacency; instead, action plans should be enacted to further protect these mangroves and prolong the provision of vital ecological goods and services. Mangrove ecosystems are known for their resilience (Heumann, 2011), and studies have shown that about 94.6% of mangrove cover remains in Belize following an assessment of mangrove cover change for the period 1980 to 2017 (Cherrington et al., 2020). This level of remaining mangrove cover renders the need to better understand the resilient characteristics of mangroves and propose conservation measures to protect this ecosystem and prolong the valuable goods and services provided in terms of maintaining fisheries and supporting biodiversity. The large population of resilient mangroves occupying the Turneffe Atoll area in Belize faces growing anthropogenic threats such as permanent clearing of land for housing and infrastructural development as well as pollution and natural factors (climate change) (Cherrington et al., 2010, 2020). These threats can potentially lead to irreversible losses of mangroves and therefore threaten mangroves' resiliency. To date, there have been few formal studies (Stoddart, 1963; Piou et al., 2006; Cherrington et al., 2010, 2020) done to evaluate mangrove-resilient features in Turneffe Atoll. Therefore, the aim of this research was to evaluate mangrove resilience to support biodiversity composition and nursery functions at Turneffe Atoll. The aim of this research was achieved through the following objectives: (1) to evaluate the resilience of mangrove ecosystems within the Turneffe Atoll, (2) to compare mangrove resilience in conservation and general use zones within the Turneffe Atoll, (3) to determine the nursery function of mangroves on fish populations and (4) to propose necessary conservation measures to further protect mangroves in the Turneffe Atoll.
2. Materials and methods
2.1 Study area
The study was carried out in Turneffe Atoll (Figure 1), located southeast of Ambergris Caye and Caye Caulker, off the coast of Belize in Central America (17.4382°N, 87.8304°W) (Chittaro et al., 2006). The Turneffe Atoll is made up of many cayes, most of which are covered with mangrove forests (covering 74.2 km2), while the perimeter of Turneffe Atoll consists of a barrier reef (Chittaro et al., 2006). The sampling design tool for ArcGIS 10.4.1 (ESRI, 2016) developed by the National Oceanic and Atmospheric Administration's (NOAA) Biogeography Branch was used to select sample sites that are representative of mangrove distribution (strata) at Turneffe Atoll (Buja and Menza, 2013). Stratified random sampling was done across 11 study sites, which span across conservation zones (Long Bogue Conservation Zone [V], Caye Bokel Conservation Area [VI], Preservation Zone [VII] and General Use Zone [VIII]) at Turneffe Atoll (Wildtracks, 2011).
2.2 Resilience of mangrove ecosystems
The point-centred quarter method (PCQM) suggested by Cintrón and Novelli (1984) and also utilised by Almada-Villela et al. (2003) was used to assess mangrove forest structure at each mangrove site. The PCQM was done in triplicates across 11 sites in August 2017 at various distances from the shore (0–95 m, in increments of 5 m), which covered 20 sample points along each transect. Sample points for PCQM were selected within zones that were predetermined with the ArcGIS 10.4.1 tool, starting from the fringing mangroves close to the shoreline. The PCQM facilitated the measurement of the closest tree to the centre point in each quadrant according to the established transect line and perpendicular. A line was established at the zero point (at shore), and a distance of 5 m between each point was used to avoid measuring the same tree twice. Four quadrants were defined at each sampling point where the transect line and a perpendicular line cross and measurements such as distance from the sampling point to the midpoint of the nearest tree (d, in metres), species, diameter at breast height (DBH, in centimetres) and height (h, in metres) were taken from the tree closest to the sampling point. The PCQM was repeated for each of the 20 sample points, and when trees measured at the previous point were encountered, the distance between these points was extended by 2 m (Cintrón and Novelli, 1984; Almada-Villela et al., 2003). The PCQM provided some community structure data about mangroves in conservation and general use zones. This sort of measurement provided an indication of mangrove composition to aid with the evaluation of how mangroves were performing within conservation zones versus the general use zone.
The level of mangrove recruitment, condition and basal area (m2/ha) at each site were determined by the rank criteria presented in Table 1, where 5 was high vulnerability and 1 was low, and the results were averaged to give an overall mangrove vulnerability rank (Ajonina et al., 2009; Ellison, 2012):
2.3 Mangrove nursery function on fish populations
Visual censuses were used to evaluate fish abundance within conservation zones compared to the general use zone, and these censuses were done during the daytime period (08.00–15.00 h) in September 2017 to ensure consistency in fish presence and activity (Nagelkerken et al., 2000; Adams and Tobias, 2003; Lök et al., 2008; Jaxion-Harm, 2010). Visual censuses were conducted over three days at a depth of 0–20 cm in 10 min intervals across two transects. The visual census technique (Nagelkerken et al., 2000; MacDonald et al., 2008) was used to estimate the fish abundance and body length of fish species in mangrove prop roots at each site. To avoid startling any fish within the two 3 × 30 m belt transects, the observers entered the water at least 20 m from each site (MacDonald et al., 2008). The census was conducted by swimming slowly along the belt transects, and the best estimation by the eye of abundance and the body length of fish species was recorded. Size classes of 5 cm were used for total body length estimation, which was guided by graduation marks on the underwater slates that were used for data recording. Water clarity was good for visual censuses across all sites except for Site 5, which had poor water clarity. Site 5 (considered an outlier) was removed for statistical analysis with fish data. Fish biomass and density recorded across surveyed sites aided in the determination of mangrove nursery function on fish populations within conservation zones versus the general use zone.
2.4 Statistical analyses
All data were analysed using the statistical programme R version 3.1.0 (R Core Team, 2021) at an acceptable α-level of 0.05 (95% confidence level). The PCQM results were used to calculate tree structural variables such as (1) density per centre point:
Fish species were grouped into families, and the estimated fish abundance for the four most dominant families (Table 4) among study sites was subjected to a t-test to determine statistical differences between study sites. To control for other factors that may influence fish abundance within mangroves, sites were grouped according to low (control) and high mangrove standing biomass for comparison. This criterion for grouping was used since all surveyed areas had surrounding mangroves and the quantity of standing biomass served as a function of ecosystem productivity (Thivakaran et al., 2020). The Shannon–Weiner diversity index was used to evaluate fish species diversity between study sites. Size estimates and published length-weight relationships available at FishBase (Froese and Pauly, 2017) were used to estimate fish biomass (Andradi-Brown et al., 2016; AGRRA, 2017).
2.5 Limitations
Limitations of the methods for data collection included accessibility within mangrove forests stands when establishing PCQM, observer bias among data collectors, sites without surrounding mangroves were not captured to serve as a true control group and poor visibility underwater affected the estimation of fish species and size. The timeline for this research was only three months based on available funding and no follow-up study was done to make a true comparison.
3. Results
3.1 Mangrove ecosystem resilience within the Turneffe Atoll
Based on the 11 sites surveyed across Turneffe Atoll (Figure 1), two species of mangroves (R. mangle and A. germinans) were found across all sites, and mangrove ecosystems were dominated by R. mangle (Figure 2) overall. However, Site 1 (general use zone, in the central lagoon), Site 2 (conservation zone V) and Site 3 (general use zone, close to Vincent’s Lagoon Special Management Area) were dominated by A. germinans (Figure 2). L. racemosa, one of the least common true mangroves found in Belize (Murray et al., 2003), was absent from all surveyed sites. Based on the ranking criteria presented in Table 1, all sites had some components of vulnerability (Table 2). Sites S1, S2, S5, S8, S9 and S10 had ranks of 1–2, indicating current resilience for these mangrove areas, while sites S3, S4, S6, S7 and S11 had ranks of 2–4, which indicated some core vulnerability for these mangrove areas (Ellison, 2015). No statistically significant relationship (p = 0.13, Spearman’s correlation) existed between fish abundance and vulnerability rank, indicating that fish abundance was not strongly dependent on the vulnerability state of mangroves. Taking into consideration all sites in conservation and general use zones, higher forest structure measurements in terms of height, DBH and standing biomass were recorded for general use zone sites (Figure 3), suggesting more healthy and older mangrove stands among these sites. A statistically significant difference (p < 0.01, Kruskal–Wallis test) in height and DBH existed among R. mangle and A. germinans, indicating that mangrove trees of the same species differed in height and DBH among the sites.
3.2 Comparison of mangrove resilience in conservation and general use zones
Based on the results of all trees across sites, it was evident that Site 2 (conservation zone V) and Site 8 (general use zone, close to the central lagoon) had higher mean height and DBH, suggesting that these were the most mature mangrove stands among the surveyed sites (Table 3). Site 7 (preservation zone VII) and Site 11 (general use zone, in the central lagoon) had lower mean height and DBH (Table 3), suggesting the least mature mangrove stands among the surveyed sites, and these sites were densely populated with R. mangle seedlings. The mean height of trees for sites 1 (general use zone, in the central lagoon), 5 (general use zone, close to the Vincent’s Lagoon Special Management Area), 9 (general use zone, close to conservation zone IV) and 10 (conservation zone VI) seemed to be similar (Table 3), possibly indicating similar maturity among these sites. No statistically significant difference in tree heights (p = 0.32, Mann–Whitney test) and DBH (p = 0.76, Mann–Whitney test) existed between the sites in conservation and general use zones. Based on mean height and DBH, tall mangrove stands were absent among the surveyed sites. Dwarf mangroves and mangrove seedlings were the least extensive, while medium mangroves were the most extensive, found at the sites in conservation and general use zones (Table 3). Mangrove standing biomass ranged from 0.11 to 95.91 kg/m2 among sites surveyed (Figure 4) and Site 8 (general use zone, close to the central lagoon) had the highest standing biomass.
3.3 Mangrove nursery function on fish populations
The surveyed sites had a rich diversity of fishes belonging to 12 families and 26 species (Table 4). The abundance and size ranges of fish by the dominant families (Haemulidae, Lutjanidae, Pomacentridae and Scaridae) (Table 4) were used to determine the nursery function of mangrove on fish populations and related to mangrove health or resilience. Site 1 (general use zone, in central lagoon) had the highest Shannon–Weiner diversity index value (H′ = 2.11), while Site 8 (general use zone, close to central lagoon) had the lowest Shannon–Weiner diversity index value (H′ = 0.18) (Table 5). Diverse communities also existed for other sites in conservation (S2, S7 and S10) and general use (S4 and S9) zones based on Shannon–Weiner diversity index values (Table 5).
Haemulidae and Lutjanidae were the most abundant families, and high fish abundance was recorded for sites 1 (general use zone, in the central lagoon), 9 (general use zone, close to conservation zone IV) and 10 (conservation zone VI) (Figure 5). Pomacentridae and Scaridae were the least abundant families, and low abundance was recorded for sites 5 (general use zone, close to Vincent’s Lagoon Special Management Area), 7 (preservation zone VII) and 11 (general use zone, in the central lagoon) (Figure 5). To control for other factors that may influence fish abundance within mangroves, sites were grouped into low (control) and high mangrove standing biomass for comparison. This comparison generally showed higher fish abundance for the dominant fish families in areas with high mangrove standing biomass (Figure 6). Based on total fish biomass for conservation and general use zones, Lutjanidae and Haemulidae had high total fish biomass, while Pomacentridae and Scaridae had low total fish biomass (Figure 7). Sites 9 (general use zone, close to conservation zone IV) and 10 had the highest total fish biomass (Figure 7). Although site one had a high fish abundance, the total fish biomass was low (Figure 7), thereby suggesting the presence of very small fishes. No statistically significant difference (p > 0.05, t-test) was found in the estimation of fish abundance between study sites in conservation and general use zones.
4. Discussion and conclusion
4.1 Discussion
The dominance of R. mangle across surveyed sites may be linked to its shade tolerant nature (DeYoe et al., 2020). The dominance of A. germinans for sites S1, S2 and S3 may be attributed to the close location of these sites to sheltered areas such as lagoons, which provide protection from direct exposure to the striking of large waves found on the outer atoll since A. germinans lacks the network of prop roots present in R. mangle to disintegrate wave action (Chatenoux and Peduzzi, 2007; Alongi, 2008). Research has also shown that R. mangle along the Pacific coast of Mexico was less affected by hurricanes compared with A. germinans due to higher shade tolerance in R. mangle seedlings and saplings (DeYoe et al., 2020).
The results of the vulnerability assessment ranking found that all sites had some components of vulnerability. Sites S1, S2, S5, S8, S9 and S10, with a ranking of 1–2, indicated mangrove areas with current resilience (Ellison, 2015). Ranks of 2–4 (such as S3, S4, S6, S7 and S11) indicated mangrove areas that were prone to some core vulnerability which could be improved by targeted management (Ellison, 2015). These results further emphasise the need for the establishment of more mangrove conservation areas to better control non-climate stressors and protect mangrove areas in the general use zone. This sort of control and protection can be achieved through improved local management and reduction of human impacts (Ajonina et al., 2009; Ellison, 2015), which will increase the resilience of species and mangrove habitats to the effects of climate change (Erwin, 2009; Ellison, 2015). Even though mangroves are protected under the Forests Act of Belize, foreign ownership along the coastline and recent trends in development, shifting land use, tourism (particularly the increased frequency of docking cruise ships) and wastewater management have exacerbated the pressures on mangroves (Ellison et al., 2020). This sort of anthropogenic pressure was evident for some sites in the general use zone, where copious amounts of rubbish were found compared to sites in the conservation zone. The anthropogenic impact of this nature may have contributed to the inherent vulnerability in the general use zone. These findings corroborate those of Suyadi and Manullang (2020), which found that plastic debris had direct and indirect negative impacts on mangrove ecosystem in Indonesia.
Sites in conservation and general use zones were all part of the Turneffe Atoll; hence, there were similarities among the structures of mangrove communities present at these sites. A phenomenon of this nature was evident since no significant difference existed for tree height and DBH between sites in conservation and general use zones. The fairly wide distribution of DBH and high DBH measurements among sites in conservation (S2 and S10) and general use (S1, S5, S8 and S9) zones indicated uneven-aged and more mature and healthier mangrove stands (Trettin et al., 2015). Additionally, the extensive distribution of overstory trees (DBH >5 cm) across surveyed sites provided more corroborating evidence about the extensive cover of old mangrove stands in the Turneffe Atoll. The nearly continuous barrier reef that runs along the coastline of Belize provides shelter for the shore, absorbs the majority of the inward wave energy and provides suitable conditions for the establishment of mangrove seedlings (Murray et al., 2003; Hamylton et al., 2023). A situation of this nature may partly account for the dense population of R. mangle seedlings present in the preservation zone (Site 7) and general use zone (Site 11) in the central lagoon. This large proportion of seedlings indicates the colonisation of forest gaps among these sites (Quadros et al., 2021). Studies by Hamylton et al. (2023) in the Northern Great Barrier Reef suggested that significant expansion of mangrove forest over a short period is linked to changing controls within the environment such as sediment deposition and transport, natural hazard impacts and development of associated reef flat sedimentary landforms.
The results of mean DBH and height across the surveyed sites showed that dwarf mangroves (typically <3 m tall and DBH > 5 cm) were among the least extensive mangrove types represented across the surveyed sites. Therefore, some of the sites surveyed in Turneffe Atoll lacked ideal environmental conditions, which restricted mangrove vegetation to a scattered cover of short mangroves. The presence of dwarf mangroves in certain sites indicated mangrove resilience since dwarf mangroves can survive natural disturbances such as hurricanes, which are accompanied by high water levels that cover these small individuals, preventing strong winds from blowing them down (Piou et al., 2006; Romero-Mujalli and Melendez, 2023). This sort of survivability of dwarf mangroves renders them possible sources of propagules for recolonisation processes subsequent to major disturbances (Piou et al., 2006). Dwarf mangrove forest is also a reflection of the plant response to environmental conditions, availability of water, pore water salinity and bioavailable nutrient limitations (Romero-Mujalli and Melendez, 2023). Medium mangroves (approximately 3–10 m tall) were the most extensive type represented across the surveyed sites, indicating that the majority of the sites surveyed were densely populated by fringing R. mangle growing at exposed sites along the coast and on cays (Kauffman et al., 2020). Kauffman et al. (2020) reported that medium mangroves typically form dense stands of trees within the interior forest environments in high precipitation areas and in semiarid environments on estuarine margins.
The site with the highest standing biomass (Site 8, general use zone) can possibly be attributed to being a more productive and older mangrove ecosystem with a higher total basal area and more resilience as compared to sites with lower standing biomass (Fromard et al., 1998; Thivakaran et al., 2020). It is expected that the preservation zone should have good mangroves since the primary objective of this zone is to preserve an entirely natural state (Wildtracks, 2011). However, this preservation zone site had low standing biomass and was constituted mostly by young individuals with low DBH, which is a predictive variable that is frequently used for estimating mangrove forest standing biomass (Fromard et al., 1998; Thivakaran et al., 2020). Low standing biomass may be attributed to aridity and subsequent hypersaline conditions (Thivakaran et al., 2020). Site 7 had good recruitment levels since all species were producing seedlings, indicating some amount of resilience and regeneration capabilities (McKee et al., 2007; Ellison, 2015). This sort of regeneration aids in the establishment and maintenance of mangrove species zonation patterns. The range of mangrove standing biomass reported in this study was similar to that reported by Thivakaran et al. (2020), although tropical countries generally have higher standing biomass. It is important to note that arid and semiarid mangroves show poor structural attributes across Mexico and the Caribbean (Thivakaran et al., 2020). Assessment of mangrove standing biomass could aid in addressing issues such as carbon sequestration and climate change (Thivakaran et al., 2020).
Fish measurements showed differences in species diversity among sites based on Shannon–Weiner indices (H′), where high H′ value was an indication of a more diverse community and even distribution of species abundance among all species recorded for that community (Bibi and Ali, 2013). Mangrove stands provide important habitats for fishes that constitute intertidal food webs (DeYoe et al., 2020). Such characteristic features may account for the diverse fish communities, and this was evident in this study, since adequate food, reproductive sites and refuge are provided. Fierro-Arcos et al. (2021) reported high Shannon–Wiener diversity for sites sampled in the Galapagos Archipelago, highlighting the role of mangroves as a habitat for fish community composed of commercially important species. Commercial fishing is allowed in the general use zone, but not in conservation zones since a no-take regime is maintained there (Wildtracks, 2011). Therefore, it is expected that fish composition in the general use zone differs from that of conservation zones; however, this was not the case since no statistically significant difference existed for fish families' composition among conservation and general use zones (p = 0.35). DeYoe et al. (2020) indicated that R. mangle in the Caribbean provides cover and nutrients for many commercially important fishes (>200 species).
Higher fish abundances were recorded for sites with medium mangrove stands (S1, S9 and S10) compared to other sites with seedling and dwarf mangrove stands (S7, S11 and S4). This was possibly due to the greater shade created by medium mangrove stands (MacDonald et al., 2008). These results are consistent with studies conducted by Jaxion-Harm (2010), which provided evidence of the probable positive correlation of fish abundance to shade (height of trees) and increased prop root complexity. Additionally, medium mangrove stands may have larger fringing R. mangle prop roots to create extensive borders around submerged habitats (DeYoe et al., 2020) that serve as nursery areas to support large fish populations and hence greater productivity. Londoño et al. (2020) also reported causal links between fish abundance and mangrove habitat via mangrove trophic contribution. These results support the conservation of mangroves to fishery resources that the Belizean community depends on for sustenance. The high abundance of commercially important fish families such as Haemulidae and Lutjanidae for Site 10 may be attributed to greater protection and reduced impact since a no-take regime is maintained for this conservation zone site compared to sites in the general use zone where commercial fishing is allowed (Wildtracks, 2011). These findings corroborated with those of Basyuni et al. (2021), who found higher fish abundance in well-preserved forests compared to sites that were converted to palm oil plantations in Indonesia. This further exemplifies the close relationship between fish abundance and mangrove conservation status. Pomacentridae and Scaridae are predominantly coral reef fishes that undertake ontogenetic migrations between coral reefs, seagrass beds and mangroves, and the unique nature of Turneffe Atoll in terms of high connectivity among mangrove stands, seagrass and coral reefs creates an ideal opportunity for migration (Wildtracks, 2011; Du et al., 2020). Therefore, the low fish abundance recorded across study sites for Pomacentridae and Scaridae may be attributed to the seldom utilisation of mangrove habitats for food and shelter. Fish species belonging to the family Scaridae are protected by legislated regulations under the Fisheries Department in Belize, but these species are illegally fished to support fishermen's livelihoods (Wildtracks, 2011; Ellison et al., 2020). This sort of illegal fishing may in part account for the low abundance of Scaridae across surveyed sites. Fierro-Arcos et al. (2021) also reported Haemulidae, Lutjanidae and Pomacentridae as some of the most dominant families in the mangroves of the Galapagos. Generally, the high fish abundance recorded in this study within high mangrove standing biomass may be linked to the structural complexity of mangroves, hence the importance of mangroves as fish feeding and nursery sites (Santamaría-Damián et al., 2023). Santamaría-Damián et al. (2023) found that mangrove sites in Mexico that were dominated by stilt root microhabitats correlated with high fish species richness, abundance and biomass. This study showed that the interaction of depth, dominance of pneumatophores, distance from the mouth of the estuary, litter production and salinity explained the patterns of fish abundance and biomass in mangroves. However, Ram et al. (2021) reported that even though active restoration served as a feasible option to restore mangrove standing biomass in the North Brazil Shelf, the fish population did not recover during their study period.
The smaller mode size range frequency (0–5 cm and 6–10 cm) for sites such as one, two and three may account for the low total fish biomass recorded for these sites, even though high fish abundance was recorded here. Additionally, the high total fish biomass for sites 9 and 10 may be attributed to the larger mode size range frequency (11–20 cm and 21–30 cm). The representative fish abundance and biomass recorded across surveyed sites shared some similarities with studies conducted by Kendall et al. (2021) on recruitment and juvenile reef fish abundance in the Caribbean, which found higher abundance among mangrove stands since these habitats are further away from the main reef and hence reduced predation. Also, factors such as natural variations in recruitment, environmental influences and hurricane disturbances may influence fish assemblage. The high fish biomass recorded for commercially important families such as Haemulidae and Lutjanidae gives an indication of mangrove resilience to support these species (Fierro-Arcos et al., 2021). Moreover, the high connectivity of mangrove stands to reef and seagrass at Turneffe Atoll provides ideal nursery habitats for commercially important juvenile fishes. Despite recent reformed and amended legislations (increased fines and stringent regulations) related to mangrove clearing laws in Belize, developers derive methods to work around these regulations and clear mangroves without permits due to poor enforcement of mangrove regulations (Ellison et al., 2020). Therefore, the need exists for the establishment of more mangrove conservation areas in Turneffe Atoll to prolong these vital ecological goods and services that the Belizean population depends upon for their livelihoods.
Based on fish size class measurements, more nursery habitats were provided by R. mangle prop root structures across sites in conservation and general use zones for fish populations. The mixture of fish densities recorded for all size classes was consistent with evidence that some juvenile fishes primarily utilise mangroves for shelter while feeding opportunistically (MacDonald et al., 2008; Kendall et al., 2021). Additionally, this research was conducted during the wet season in Belize, and this season tends to correlate with high recruitment of juvenile fishes to mangrove communities since a high abundance of zooplankton exists to provide greater food abundance. Furthermore, mangrove prop roots play a critical role as habitat for juvenile fishes, and this was for studies in the Caribbean that showed the resilience of these ecosystems considering growing pressures from coastal development, fisheries and climate change (Kendall et al., 2021).
Based on the results of this study, more resilient and healthier mangrove stands constituted sites (especially sites 8 and 9) in the general use zone, which are not well protected in the Turneffe Atoll Marine Reserve (TAMR). Based on the sample design for this study, the surveyed sites were selected based on mangrove distribution, and only three conservation zone sites had a representative distribution of mangroves compared to eight sites in the general use zone. Therefore, mangroves in conservation zones may be underrepresented, and future studies should look at an equal proportion of sites as well as sites without surrounding mangroves to make better comparisons. Increased protection in the general use zone is critical given the connectivity that mangroves share with other marine ecosystems to foster higher immigration rates from nursery habitats and possibly more production to support livelihoods. Site 9 is close to the Blackbird Caye conservation zone, which is privately owned and slated for further development given the major role that tourism plays in the economic development of Belize (TICAC, 2003; Ellison et al., 2020). This sort of development will impact mangrove ecosystems and lead to irreversible losses of mangroves, thereby threatening mangrove resilience (Ellison et al., 2020). Mangrove losses can also affect water quality since pollutants from wastewater would not be readily removed and transformed and fish abundance may decline since nursery habitats, which provide shelter for juvenile fishes are removed (Polidoro et al., 2010; Wang et al., 2010; Ellison et al., 2020). Therefore, a more careful evaluation of conservation measures is needed for mangroves specifically. Some of these conservation measures are outlined in Table 6. Future research should focus on more long-term monitoring of mangrove forests within Turneffe Atoll to better assess the impacts of different types of disturbances over time. These long-term monitoring studies should consider sites without surrounding mangroves to capture a true control group for comparative relations. Better quantification of the structure and extent of prop roots and their correlation to fish abundance as well as combining visual censuses with unattended, continuous-recording method such as underwater video system would answer additional questions.
4.2 Conclusion
The physical and ecological characteristics of Belize are like those of other parts of the Caribbean and Central America. However, in the Caribbean region, Belize is unusual since a large portion of its coastline is covered by mangrove, and an extensive composition of mangrove is found at Turneffe Atoll. Mangroves in conservation zones at Turneffe Atoll are possibly underrepresented since a larger composition of resilient mangroves constitutes the general use zone. Major gaps exist in the protection of coastal and marine mangroves within Turneffe Atoll. Although the findings of this research only form a baseline, the need exists for the establishment of more mangrove conservation areas in Turneffe Atoll due to the presence of more resilient and healthier mangroves in the general use zone. The establishment of more mangrove conservation areas would better facilitate long-term, ongoing monitoring programmes.
Figures
Figure 1
Map of surveyed sites
Figure 2
Species composition in conservation and general use zones
Figure 3
Mangrove forest structure across sites surveyed based on height, DBH and biomass classification
Figure 4
Comparison of mangrove standing biomass in conservation and general use zones
Figure 5
Comparison of fish abundance across surveyed sites
Figure 6
Comparison of fish abundance across sites with low and high mangrove standing biomass
Figure 7
Comparison of total fish biomass across surveyed sites
Ranking criteria for mangrove vulnerability assessment results
| Rank | |||||
|---|---|---|---|---|---|
| Sensitivity components | 1 | 2 | 3 | 4 | 5 |
| Mangrove condition | No or slight impact | Moderate impact | Rather high impact | High impact | Severe impact |
| Mangrove basal area (m2/ha) | >25 | 15–25 | 10–15 | 5–10 | <5 |
| Recruitment | All species producing seedlings | Most species producing seedlings | Some species producing seedlings | Just a few seedlings | No seedlings |
Source(s): Ellison (2015)
Vulnerability assessment ranking results for sites in conservation and general use zones
| Conservation zone | General use zone | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Sensitivity components | S2 | S7 | S10 | S1 | S3 | S4 | S5 | S6 | S8 | S9 | S11 |
| Mangrove condition* | 1 | 1 | 1 | 1 | 2 | 2 | 1 | 2 | 1 | 2 | 1 |
| Mangrove basal area (m2/ha)* | 2 | 5 | 2 | 2 | 3 | 5 | 2 | 4 | 2 | 3 | 5 |
| Recruitment* | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 2 | 1 | 1 | 1 |
| Total | 4 | 7 | 4 | 4 | 7 | 8 | 4 | 8 | 4 | 6 | 7 |
| Number of components | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 |
| Vulnerability rank | 1.3 | 2.3 | 1.3 | 1.3 | 2.3 | 2.7 | 1.3 | 2.7 | 1.3 | 2 | 2.3 |
Note(s): *Values based on ranking criteria presented in Table 1, The last row gives averaged rank results of the overall vulnerability rank for each site (shown in italic)
Source(s): Authors’ own work
Summary of sites based on mangrove type classification scheme
| Sites | Zones | Mean DBH ± SD (cm) | Mean height ± SD (m) | Mangrove type |
|---|---|---|---|---|
| S1 | General use | 26.22 ± 15.25 | 4.48 ± 2.14 | Medium |
| S2 | Conservation | 30.30 ± 15.30 | 4.99 ± 1.97 | Medium |
| S3 | General use | 20.96 ± 18.81 | 3.46 ± 2.35 | Medium |
| S4 | General use | 13.61 ± 7.97 | 2.90 ± 0.80 | Dwarf |
| S5 | General use | 24.62 ± 15.63 | 4.20 ± 2.03 | Medium |
| S6 | General use | 14.17 ± 10.29 | 2.26 ± 0.94 | Dwarf |
| S7 | Conservation | 3.02 ± 4.82 | 1.23 ± 0.42 | Seedling |
| S8 | General use | 32.61 ± 13.00 | 6.44 ± 1.81 | Medium |
| S9 | General use | 26.08 ± 18.09 | 4.64 ± 1.90 | Medium |
| S10 | Conservation | 27.59 ± 15.02 | 4.15 ± 1.81 | Medium |
| S11 | General use | 1.49 ± 0.44 | 0.64 ± 0.11 | Seedling |
Source(s): Authors’ own work and Murray et al. (2003) and Kauffman and Donato (2012)
Fish species observed at study sites in conservation and general use zones
| Family/species | Conservation zone abundance (m2) | General use zone abundance (m2) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| S2 | S7 | S10 | S1 | S3 | S4 | S5 | S6 | S8 | S9 | S11 | |
| Acanthuridae | |||||||||||
| Acanthurus bahianus | 0.03 | ||||||||||
| Belonidae | |||||||||||
| Ablennes hians | 0.06 | ||||||||||
| Carangidae | |||||||||||
| Caranx ruber | 0.01 | ||||||||||
| Centropomidae | |||||||||||
| Centropomus undecimalis | 0.02 | ||||||||||
| Chaetodontidae | |||||||||||
| Chaetodon capistratus | 0.02 | 0.01 | 0.02 | ||||||||
| Gerreidae | |||||||||||
| Gerres cinereus | 0.05 | 0.02 | 0.03 | 0.03 | |||||||
| Haemulidae | |||||||||||
| Haemulon flavolineatum | 0.24 | 0.03 | 0.01 | 0.03 | 0.01 | 0.04 | |||||
| Haemulon sciurus | 0.01 | 0.02 | 0.19 | 0.15 | 0.03 | 0.04 | 0.01 | 0.1 | |||
| Haemulon aurolineatum | 0.24 | ||||||||||
| Haemulon macrostomum | 0.12 | 0.08 | 0.03 | 0.17 | 0.04 | ||||||
| Haemulon plumierii | 0.06 | 0.05 | |||||||||
| Haemulon carbonarium | 0.27 | 0.12 | |||||||||
| Haemulon parra | 0.04 | 0.03 | |||||||||
| Lutjanidae | |||||||||||
| Lutjanus apodus | 0.11 | 0.01 | 0.43 | 0.19 | 0.31 | 0.19 | 0.23 | 0.21 | 0.38 | 0.06 | |
| Lutjanus griseus | 0.03 | 0.04 | 0.09 | 0.02 | 0.04 | 0.01 | |||||
| Lutjanus mahogoni | 0.05 | 0.08 | 0.17 | 0.02 | 0.04 | 0.03 | |||||
| Lutjanus jocu | 0.01 | 0.06 | |||||||||
| Labridae | |||||||||||
| Halichoeres bivittatus | 0.05 | 0.06 | 0.03 | ||||||||
| Halichoeres garnoti | 0.07 | ||||||||||
| Pomacentridae | |||||||||||
| Abudefduf saxatilis | 0.06 | 0.03 | 0.06 | 0.04 | 0.05 | 0.06 | 0.01 | 0.01 | 0.06 | 0.06 | |
| Stegastes variabilis | 0.01 | ||||||||||
| Stegastes adustus | 0.01 | 0.07 | 0.01 | ||||||||
| Scaridae | |||||||||||
| Scarus taeniopterus | 0.02 | 0.03 | 0.03 | ||||||||
| Sparisoma viride | 0.01 | 0.07 | 0.02 | 0.01 | |||||||
| Scarus iserti | 0.04 | 0.01 | 0.1 | ||||||||
| Sphyraenidae | |||||||||||
| Sphyraena barracuda | 0.02 | 0.07 | 0.03 | 0.02 | 0.01 | ||||||
Source(s): Authors’ own work
Diversity of ichthyofauna in conservation and general use zones
| Sites | Zones | Shannon–Weiner diversity index (H′) |
|---|---|---|
| S1 | General use | 2.11 |
| S2 | Conservation | 1.76 |
| S3 | General use | 1.43 |
| S4 | General use | 1.75 |
| S6 | General use | 1.31 |
| S7 | Conservation | 1.84 |
| S8 | General use | 0.18 |
| S9 | General use | 1.60 |
| S10 | Conservation | 1.88 |
| S11 | General use | 1.10 |
Source(s): Authors’ own work
Conservation action plan
| Action | Resource needs | Responsibility | Timeline | Comments |
|---|---|---|---|---|
| Better waste management through beach cleanup and controlling pollution sources through enactment and stringent enforcement of waste management legislation | Donor and private/public financing (ca. US$15,000) Technology transfer | Belize Coastal Zone Management Authority and Institute, Belize Association of Private Protected Areas, Belizean Mangrove Conservation Network, Government of Belize | 5 years | Such actionable measures will facilitate greater elimination of non-climate stressors on mangroves such as pollution |
| Develop additional policies and enforcement to provide a robust framework for mangrove management and ensure the halting of mangrove forests losses in the general use zone (in keeping with Sustainable Development Goal Target 15.2.) | Public financing (ca. US$10,000) | Government of Belize | 5 years | These policy measures will aid in preventing destruction to mangrove nursery areas and reducing the impacts on other nearshore marine ecosystems. Provisions could also be made for commercial fishing in a sustainable manner since the general use zone provides fertile and valuable fishing ground |
| Incentivised outreach and educational programmes for landowners across Belize to promote effective mangrove conservation and restoration and foster mangrove conservation networks | Donor and private/public financing (ca. US$50,000) | Belize Association of Private Protected Areas, Belizean Mangrove Conservation Network, Government of Belize | 2 years | Active participation in mangrove management and conservation by individuals and experts who use coastal resources daily will increase understanding and awareness of the ecosystem services provided by Belize’s mangroves |
| Robust Communication Strategy to better communicate enacted zoning policies that guide development and enforce regulations, especially to foreign property-owners | Donor and private/public financing (ca. US$10,000) | Government of Belize, Belize Coastal Zone Management Authority and Institute, Belizean Mangrove Conservation Network | 3 years | Apprise foreign property-owners in a more effective manner of domestic mangrove regulations in Belize |
| Long-term monitoring surveys to capture environmental drivers such as climate change, sea-level fluctuations and anthropogenic pressure on the biodiversity and evolution of mangrove ecosystems | Donor and private/public financing (ca. US$20,000) Technology transfer | Belize Association of Private Protected Areas, Belizean Mangrove Conservation Network | 10 years | The lessons learnt from these surveys may be useful to inform conservation and restoration actions |
Source(s): Authors’ own work and Adger et al. (2007), Gilman et al. (2008) and Ellison et al. (2020)
References
Adams, A.J. and Tobias, W.J. (2003), “Red mangrove prop-root habitat as a finfish nursery area : a case study of Salt River Bay, St. Croix, U.S.V.I”, Proceedings of the 46th Gulf and Caribbean Fisheries Institute, Government of the Virgin Islands, Department of Planning and Natural Resources, Division of Fish and Wildlife, St. Croix.
Adger, W.N., Arnell, N.W. and Tompkins, E.L. (2007), “Successful adaptation to climate change across scales”, Global Environmental Change, Vol. 15, pp. 77-86.
AGRRA (2017), “Atlantic and Gulf Rapid Reef Assessment”, Ocean Research & Education Foundation, Inc. & AGRRA, available at: http://www.agrra.org/ (accessed 19 September 2017).
Ajonina, G., Tchikangwa, B., Chuyong, G. and Tchamba, M. (2009), “The challenges and prospects of developing a community based generalizable method to assess mangrove ecosystems vulnerability and adaptation to climate change impacts: experience from Cameroon”, Nature and Faune, Vol. 24, pp. 16-25.
Almada-Villela, P.C., Sale, P.F., Gold-Bouchot, G. and Kjerfve, B. (2003), “Manual of methods for the MBRS synoptic monitoring program”, Mesoamerican Barrier Reef Systems Project, Belize City.
Alongi, D.M. (2008), “Mangrove forests: resilience, protection from tsunamis, and responses to global climate change”, Estuarine, Coastal and Shelf Science, Vol. 76, pp. 1-13, doi: 10.1016/j.ecss.2007.08.024.
Andradi-Brown, D.A., Gress, E., Wright, G., Exton, D.A. and Rogers, A.D. (2016), “Reef fish community biomass and trophic structure changes across shallow to upper- mesophotic reefs in the Mesoamerican barrier reef, Caribbean”, PLoS ONE, Vol. 11 No. 6, pp. 1-19, doi: 10.1371/journal.pone.0156641.
Aschenbroich, A., Michaud, E., Stieglitz, T., Fromard, F., Gardel, A., Tavares, M. and Thouzeau, G. (2016), “Brachyuran crab community structure and associated sediment reworking activities in pioneer and young mangroves of French Guiana, South America”, Estuarine, Coastal and Shelf Science, Vol. 182, pp. 60-71, doi: 10.1016/j.ecss.2016.09.003.
Basyuni, M., Slamet, B., Sulistiyono, N., Munir, E., Vovides, A.G. and Bunting, P. (2021), “Physicochemical characteristic, nutrient, and fish production in different types of mangrove forest in North Sumatra and Aceh Provinces of Indonesia”, Kuwait Journal of Science, Vol. 48 No. 3, pp. 1-14, doi: 10.48129/kjs.v48i3.9160.
Betts, T. (2006), An Assessment of Mangrove Cover and Forest Structure in Las Perlas, Panama, Heriot-Watt University, Edinburgh, available at: http://www.stri.si.edu/sites/darwin_initiative/PDFs/TaniaBetts.pdf
Bibi, F. and Ali, Z. (2013), “Measurement of diversity indices of avian communities at Taunsa barrage wildlife sanctuary, Pakistan”, Journal of Animal and Plant Sciences, Vol. 23 No. 2, pp. 469-474.
Buja, K. and Menza, C. (2013), “Sampling design tool for ArcGIS – instruction manual”, MD.
Capote-Fuentes, R.T. (2007), Resilience of Mangroves on the South Coast of Havana province, Cuba, Rheinischen Friedrich-Wilhelms-Universität Bonn, available at: http://hss.ulb.uni-bonn.de/diss_onlineelektronischpubliziert
Chatenoux, B. and Peduzzi, P. (2007), “Impacts from the 2004 Indian Ocean Tsunami: analysing the potential protecting role of environmental features”, Natural Hazards, Vol. 40 No. 2, pp. 289-304, doi: 10.1007/s11069-006-0015-9.
Cherrington, E.A., Griffin, R.E., Anderson, E.R., Hernandez Sandoval, B.E., Flores-Anderson, A.I., Muench, R.E., Markert, K.N., Adams, E.C., Limaye, A.S. and Irwin, D.E. (2020), “Use of public Earth observation data for tracking progress in sustainable management of coastal forest ecosystems in Belize, Central America”, Remote Sensing of Environment, Vol. 245, 111798, doi: 10.1016/j.rse.2020.111798.
Cherrington, E.A., Hernandez, B.E., Trejos, N.E., Smith, O.A., Anderson, E.A., Flores, A.I. and Garcia, B.C. (2010), “Identification of threatened and resilient mangroves in the Belize barrier reef system”, Source Water Center for the Humid Tropics of Latin America and the Caribbean (CATHALAC).
Chittaro, P.M., Usseglio, P., Fryer, B. and Sale, P. (2006), “Spatial variation in otolith chemistry of Lutjanus apodus at Turneffe Atoll, Belize”, Estuarine, Coastal and Shelf Science, Vol. 67 No. 4, pp. 673-680, doi: 10.1016/j.ecss.2005.12.014.
Cintrón, G. and Novelli, Y.S. (1984), “Methods for studying mangrove structure”, in Snedaker, S.C. and Snedaker, J.G. (Eds), The Mangrove Ecosystem: Research Methods, United Nations Educational, Scientific and Cultural Organization, Paris, pp. 91-113.
DeYoe, H., Lonard, R.I., Judd, F.W., Stalter, R. and Feller, I. (2020), “Biological flora of the tropical and subtropical intertidal zone: literature review for Rhizophora mangle L”, Journal of Coastal Research, Vol. 36 No. 4, pp. 857-884, doi: 10.2112/JCOASTRES-D-19-00088.1.
Dharanirajan, K., Thanikachalam, M., Gurugnanam, B., Narayanam, R.M. and Falia, G.C. (2010), “Remote sensing and GIS for the study of coastal ecosystem changes and its conservation”, International Journal of Earth Sciences and Engineering, Vol. 3 No. 4, pp. 512-524.
Du, J., Xie, M., Wang, Y., Chen, Z., Liu, W., Liao, J. and Chen, B. (2020), “Connectivity of fish assemblages along the mangrove-seagrass-coral reef continuum in Wenchang, China”, Acta Oceanologica Sinica, Vol. 39 No. 8, pp. 43-52, doi: 10.1007/s13131-019-1490-7.
Ellison, J.C. (2012), “Climate change vulnerability assessment and adaptation planning for mangrove systems”, Washington, D.C.
Ellison, J.C. (2015), “Vulnerability assessment of mangroves to climate change and sea-level rise impacts”, Wetlands Ecology and Management, Vol. 23 No. 2, pp. 115-137, doi: 10.1007/s11273-014-9397-8.
Ellison, A.M., Felson, A.J. and Friess, D.A. (2020), “Mangrove rehabilitation and restoration as experimental adaptive management”, Frontiers in Marine Science, Vol. 7, p. 327, doi: 10.3389/fmars.2020.00327.
Erwin, K.L. (2009), “Wetlands and global climate change: the role of wetland restoration in a changing world”, Wetlands Ecology and Management, Vol. 17 No. 1, pp. 71-84, doi: 10.1007/s11273-008-9119-1.
ESRI (2016), ArcGIS for Desktop, Esri, Redlands, available at: https://www.esri.com
Fierro-Arcos, D., Marín Jarrín, J., Aburto-Oropeza, O., Harvey, E., Rastoin-Laplane, E. and Salinas-de-León, P. (2021), “Mangrove fish assemblages reflect the environmental diversity of the Galapagos Islands”, Marine Ecology Progress Series, Vol. 664, pp. 183-205, doi: 10.3354/meps13628.
Froese, R. and Pauly, D. (2017), “FishBase, world wide web electronic publication”, available at: http://www.fishbase.org (accessed 20 September 2017).
Fromard, F., Puig, H., Mougin, E., Marty, G., Betoulle, J.L. and Cadamuro, L. (1998), “Structure, above-ground biomass and dynamics of mangrove ecosystems: new data from French Guiana”, Oecologia, Vol. 115 No. 1, pp. 39-53, doi: 10.1007/s004420050489.
Gilman, E.L., Ellison, J., Duke, N.C. and Field, C. (2008), “Threats to mangroves from climate change and adaptation options: a review”, Aquatic Botany, Vol. 89, pp. 237-250, doi: 10.1016/j.aquabot.2007.12.009.
Gouvêa, L.P., Serrão, E.A., Cavanaugh, K., Gurgel, C.F.D., Horta, P.A. and Assis, J. (2022), “Global impacts of projected climate changes on the extent and aboveground biomass of mangrove forests”, Diversity and Distributions, Vol. 28 No. 11, pp. 2349-2360, doi: 10.1111/ddi.13631.
Hamylton, S., Kelleway, J., Rogers, K., McLean, R., Tynan, Z.N. and Repina, O. (2023), “Mangrove expansion on the low wooded islands of the Great Barrier Reef”, Proceedings of the Royal Society B, Vol. 290 No. 2010, 20231183, doi: 10.1098/rspb.2023.1183.
Heumann, B.W. (2011), “An object-based classification of mangroves using a hybrid decision tree-support vector machine approach”, Remote Sensing, Vol. 3 No. 11, pp. 2440-2460, doi: 10.3390/rs3112440.
Jaxion-Harm, J.C. (2010), “The relationship between coral-reef fish (larvae, juveniles, and adults) and mangroves: a case study in Honduras”, University of Oxford, available at: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.543014
Kauffman, J.B. and Donato, D.C. (2012), Protocols for the Measurement, Monitoring and Reporting of Structure, Biomass and Carbon Stocks in Mangrove Forests, Center for International Forestry Research, Bogor, Vol. 86.
Kauffman, J.B., Adame, M.F., Arifanti, V.B., Schile‐Beers, L.M., Bernardino, A.F., Bhomia, R.K., Donato, D.C., Feller, I.C., Ferreira, T.O., Jesus Garcia, M.d.C., MacKenzie, R.A., Megonigal, J.P., Murdiyarso, D., Simpson, L. and Hernández Trejo, H. (2020), “Total ecosystem carbon stocks of mangroves across broad global environmental and physical gradients”, Ecological Monographs, Vol. 90 No. 2, e01405, doi: 10.1002/ecm.1405.
Kendall, M.S., Williams, B.L., Ruffo, A., Winship, A.J., Siceloff, L., Adams, A. and Tobias, W. (2021), “Resampling 25 years later reveals fewer species but higher abundance of juvenile fishes in a Caribbean mangrove bay”, Bulletin of Marine Science, Vol. 97 No. 1, pp. 53-74, doi: 10.5343/bms.2020.0005.
Lök, A., Gül, B., Ulaş, A., Ozan Düzbastilar, F. and Metin, C. (2008), “Diel variations on the fish assemblages at artificial reefs in two different environments of the Aegean sea (western coast of Turkey)”, Turkish Journal of Fisheries and Aquatic Sciences, Vol. 8, pp. 79-85.
Londoño, L.A.S., Leal-Flórez, J. and Blanco-Libreros, J.F. (2020), “Linking mangroves and fish catch: a correlational study in the southern Caribbean Sea (Colombia)”, Bulletin of Marine Science, Vol. 96 No. 3, pp. 415-429, doi: 10.5343/bms.2019.0022.
Ma, W., Wang, W., Tang, C., Chen, G. and Wang, M. (2020), “Zonation of mangrove flora and fauna in a subtropical estuarine wetland based on surface elevation”, Ecology and Evolution, Vol. 10 No. 14, pp. 7404-7418, doi: 10.1002/ece3.6467.
MacDonald, J.A., Glover, T. and Weis, J.S. (2008), “The impact of mangrove prop-root epibionts on juvenile reef fishes: a field experiment using artificial roots and epifauna”, Estuaries and Coasts, Vol. 31 No. 5, pp. 981-993, [Preprint], doi: 10.1007/s12237-008-9083-2.
McKee, K.L., Rooth, J.E. and Feller, I.C. (2007), “Mangrove recruitment after forest disturbance is facilitated by herbaceous species in the Caribbean”, Ecological Applications, Vol. 17 No. 6, pp. 1678-1693, doi: 10.1890/06-1614.1.
McSherry, M., Davis, R.P., Andradi-Brown, D.A., Ahmadia, G.N., Van Kempen, M. and Wingard Brian, S. (2023), “Integrated mangrove aquaculture: the sustainable choice for mangroves and aquaculture?”, Frontiers in Forests and Global Change, Vol. 6, 1094306, doi: 10.3389/ffgc.2023.1094306.
Murray, M.R., Zisman, S., Furley, P., Munro, D., Gibson, J., Ratter, J., Bridgewater, S., Minty, C. and Place, C. (2003), “The mangroves of Belize part 1. distribution, composition and classification”, Forest Ecology and Management, Vol. 174 Nos 1-3, pp. 265-279, doi: 10.1016/S0378-1127(02)00036-1.
Nagelkerken, I. (2009), “Evaluation of nursery function of mangroves and seagrass beds for tropical decapods and reef fishes: patterns and underlying mechanisms”, in Nagelkerken, I. (Ed.), Ecological Connectivity Among Tropical Coastal Ecosystems, Springer Science+Business Media B.V, London New York, pp. 357-400, doi: 10.1007/978-90-481-2406-0.
Nagelkerken, I., van der Velde, G., Gorissen, M., Meijer, G., Van't Hof, T. and den Hartog, C. (2000), “Importance of mangroves, seagrass beds and the shallow coral reef as a nursery for important coral reef fishes, using a visual census technique”, Estuarine, Coastal and Shelf Science, Vol. 51 No. 1, pp. 31-44, doi: 10.1006/ecss.2000.0617.
Nagelkerken, I., De Schryver, A., Verweij, M., Dahdouh-Guebas, F., van der Velde, G. and Koedam, N. (2010), “Differences in root architecture influence attraction of fishes to mangroves: a field experiment mimicking roots of different length, orientation, and complexity”, Journal of Experimental Marine Biology and Ecology, Vol. 396 No. 1, pp. 27-34, doi: 10.1016/j.jembe.2010.10.002.
Numbere, A.O. (2021), “Natural seedling recruitment and regeneration in deforested and sand-filled Mangrove forest at Eagle Island, Niger Delta, Nigeria”, Ecology and Evolution, Vol. 11 No. 7, pp. 3148-3158, doi: 10.1002/ece3.7262.
Piou, C., Feller, I.C., Berger, U. and Chi, F. (2006), “Zonation patterns of Belizean offshore mangrove forests 41 years after a catastrophic hurricane”, Biotropica, Vol. 38 No. 3, pp. 365-374, doi: 10.1111/j.1744-7429.2006.00156.x.
Polidoro, B.A., Carpenter, K.E., Collins, L., Duke, N.C., Ellison, A.M., Ellison, J.C., Farnsworth, E.J., Fernando, E.S., Kathiresan, K., Koedam, N.E., Livingstone, S.R., Miyagi, T., Moore, G.E., Ngoc Nam, V., Ong, J.E., Primavera, J.H., Salmo, S.G., Sanciangco, J.C., Sukardjo, S., Wang, Y. and Yong, J.W.H. (2010), “The loss of species: mangrove extinction risk and geographic areas of global concern”, PLoS ONE, Vol. 5 No. 4, e10095, doi: 10.1371/journal.pone.0010095.
Quadros, A.F., Helfer, V., Nordhaus, I., Reuter, H. and Zimmer, M. (2021), “Functional traits of terrestrial plants in the intertidal: a review on mangrove trees”, Biological Bulletin, Vol. 241 No. 2, pp. 123-139, doi: 10.1086/716510.
R Core Team (2021), R: A Language and Environment for Statistical Computing, R Foundation for Statistical Computing, Vienna, available at: https://www.r-project.org/
Ram, M.A., Caughlin, T.T. and Roopsind, A. (2021), “Active restoration leads to rapid recovery of aboveground biomass but limited recovery of fish diversity in planted mangrove forests of the North Brazil Shelf”, The Journal of the Society of Ecological Restoration, Vol. 29 No. 5, [Preprint], doi: 10.1111/rec.13400.
Romero-Mujalli, G. and Melendez, W. (2023), “Nutrients and trace elements of semi-arid dwarf and fully developed mangrove soils, northwestern Venezuela”, Environmental Earth Sciences, Vol. 82 No. 1, p. 51, doi: 10.1007/s12665-022-10701-5.
Roy, P., Pal, S.C., Chakrabortty, R., Chowdhuri, I., Saha, A. and Shit, M. (2023), “Effects of climate change and sea-level rise on coastal habitat: vulnerability assessment, adaptation strategies and policy recommendations”, Journal of Environmental Management, Vol. 330, 117187, doi: 10.1016/j.jenvman.2022.117187.
Rull, V. (2023), “Rise and fall of Caribbean mangroves”, Science of the Total Environment, Vol. 885, 163851, doi: 10.1016/j.scitotenv.2023.163851.
Santamaría-Damián, S., Tovilla-Hernández, C., Romero-Berny, E.I., Damon, A., Navarro-Martínez, A. and Ortega-Argueta, A. (2023), “Effect of mangrove complexity and environmental variables on fish assemblages across a tropical estuarine channel of the Mexican Pacific”, Wetlands, Vol. 43 No. 5, p. 50, doi: 10.1007/s13157-023-01700-8.
Seddon, A.W.R., Froyd, C.A., Leng, M.J., Milne, G.A. and Willis, K.J. (2011), “Ecosystem resilience and threshold response in the Galapagos coastal zone”, PLoS ONE, Vol. 6 No. 7, e22376, doi: 10.1371/journal.pone.0022376.
Singh, J.K. (2020), “Structural characteristics of mangrove forest in different coastal habitats of Gulf of Khambhat arid region of Gujarat, west coast of India”, Heliyon, Vol. 6 No. 8, e04685, doi: 10.1016/j.heliyon.2020.e04685.
Sreelekshmi, S., Nandan, S.B., Kaimal, S.V., Radhakrishnan, C. and Suresh, V. (2020), “Mangrove species diversity, stand structure and zonation pattern in relation to environmental factors — a case study at Sundarban delta, east coast of India”, Regional Studies in Marine Science, Vol. 35, 101111, doi: 10.1016/j.rsma.2020.101111.
Stoddart, D.R. (1963), “Effects of hurricane Hattie on the British Honduras reefs and cays”, Atoll Research Bulletin, Vol. 95, pp. 1-142, doi: 10.5479/si.00775630.95.1.
Suyadi and Manullang, C.Y. (2020), “Distribution of plastic debris pollution and it is implications on mangrove vegetation”, Marine Pollution Bulletin, Vol. 160, 111642, doi: 10.1016/j.marpolbul.2020.111642.
Thivakaran, G.A., Sharma, S.B., Chowdhury, A. and Murugan, A. (2020), “Status, structure and environmental variations in semi-arid mangroves of India”, Journal of Forestry Research, Vol. 31 No. 1, pp. 163-173, doi: 10.1007/s11676-018-0793-4.
TICAC (2003), “Turneffe Islands development guidelines 2003”, Belize City.
Trettin, C.C., Stringer, C.E. and Zarnoch, S.J. (2015), “Composition, biomass and structure of mangroves within the Zambezi river delta”, Wetlands Ecology and Management, Vol. 24 No. 2, pp. 173-186, [Preprint], doi: 10.1007/s11273-015-9465-8.
Turschwell, M.P., Tulloch, V.J., Sievers, M., Pearson, R.M., Andradi-Brown, D.A., Ahmadia, G.N., Connolly, R.M., Bryan-Brown, D., Lopez-Marcano, S., Adame, M.F. and Brown, C.J. (2020), “Multi-scale estimation of the effects of pressures and drivers on mangrove forest loss globally”, Biological Conservation, Vol. 247, 108637, doi: 10.1016/j.biocon.2020.108637.
Wang, M., Zhang, J., Tu, Z., Gao, X. and Wang, W. (2010), “Maintenance of estuarine water quality by mangroves occurs during flood periods: a case study of a subtropical mangrove wetland”, Marine Pollution Bulletin, Vol. 60 No. 11, pp. 2154-2160, doi: 10.1016/j.marpolbul.2010.07.025.
Ward, R.D., Friess, D.A., Day, R.H. and Mackenzie, R.A. (2016), “Impacts of climate change on mangrove ecosystems: a region by region overview”, Ecosystem Health and Sustainability, Vol. 2 No. 4, doi: 10.1002/ehs2.1211.
Wildtracks (2011), “Turneffe atoll marine reserve management plan”, Belize City.
Further reading
Hutchison, J., Manica, A., Swetnam, R., Balmford, A. and Spalding, M. (2014), “Predicting global patterns in mangrove forest biomass”, Conservation Letters, Vol. 7, pp. 233-240, doi: 10.1111/conl.12060.
Acknowledgements
The authors extend their gratitude to the following organisations that funded this research: CARPIMS and the University of Belize Environmental Research Institute. The authors also thank the staff and personnel of the University of Belize Calabash Caye Field Station for their hospitality, provision of research materials and logistical support, and thank Tracy Gazobatu, Elisabeta Maiwiriwiri and Roberto Gongora for their assistance with the fieldwork. The comments of two anonymous reviewers significantly benefitted this paper. The funders had no role in study design, data collection and analysis, the decision to publish or the preparation of the manuscript.