Next Article in Journal
New Contributions to Entoloma sect. Madida (Entolomataceae, Agaricales) from Subtropical Montane Forests of China: Two New Taxa
Previous Article in Journal
Assessing Plant Species Turnover in Grasslands of South Africa
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Diversity
Volume 18
Issue 6
10.3390/d18060385
diversity-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Ecological Restoration of Mangrove Forests: Early Ecological Responses to Hydrological Restoration in Eastern Africa

by
Alberto de Jesus Fernando
1,*,
Henriques Balidy
2,
Maria Alberto Cuambe
1,
Faustino César
1 and
Célia da Conceição Macamo
1
1
Department of Biological Sciences, Eduardo Mondlane University, Main University Campus, Av. Julius Nherere nr. 3453, Maputo 1100, Mozambique
2
World Wildlife Fund (WWF) Mozambique, Rua da Mesquita, Marromeu 2115, Mozambique
*
Author to whom correspondence should be addressed.
Diversity 2026, 18(6), 385; https://doi.org/10.3390/d18060385 (registering DOI)
Submission received: 27 March 2026 / Revised: 1 May 2026 / Accepted: 3 May 2026 / Published: 22 June 2026
(This article belongs to the Section Marine Diversity)
Browse Figures
Versions Notes

Abstract

Mangrove forests in northern Mozambique were impacted by human and natural pressures, causing channel blockage, permanent flooding, and tree die back. To address the issue, hydrological restoration was carried out in August 2024, excavating 6.88 km of channels, with impact in 38 ha of degraded mangrove. The intervention area was divided into three zones, upper, middle, and lower, based on ecological and environmental characteristics. This study reports on the monitoring carried out 4 and 10 months later. Site salinity approached optimal levels for mangrove growth, dropping by 56% in high-salinity zones, and increasing above 100% in freshwater-invaded zones. The intervention also homogenized the previously distinct upper, middle, and lower zones to more statistically similar groups (Dunn post hoc: p > 0.05). Moreover, seedling density increased from 57.1 ± 44.1 to 4864 ± 1778.6 seedlings/ha; additionally, regenerating species increased in numbers (1 to 3 mangrove species in middle zone; and 0 to 3 mangrove species in lower zone). The study also reports the dieback of competing species, Juncus kraussii and Cyperus articulates. These changes result from the improved tidal flow and general habitat conditions in the restored site. This restoration offers a model for scaling up restoration efforts across the region, where ecological restoration remains underrepresented in many mangrove restoration initiatives.

1. Introduction

Mangrove forests are essential for a variety of coastal ecosystem services in tropical and subtropical regions, such as regulating greenhouse gases and carbon sequestration [1,2] providing coastal protection against wave energy-induced erosion, coastal storms, and cyclones; and harboring a great range of diverse fauna and flora [3]. Mangroves are nonetheless sensitive and threatened by a variety of human and natural impacts that cause a reduction in coverage area and bring alterations to the soil, fauna, and flora [3].
In recent years, in recognition of the importance of mangroves and the negative impacts of their degradation, there has been an increase in restoration and conservation initiatives around the world [1,4], led by government institutions, civil society organizations, local communities, and educational institutions [5,6,7]. Restoration approaches are usually limited to active planting of propagules and seedlings, aiming to recover the fauna and flora of degraded areas. Despite the efforts, many of the initiatives have failed to achieve success due to the use of inappropriate methods [8,9] that, in many cases, do not eliminate the primary cause of degradation [10].
Depending on the level of the degradation, mangrove forests have the ability to successfully self-restore or undergo secondary succession within 15 to 30 years if the normal tidal hydrology has not been affected. Hence, any restoration planning should first consider assessing the tidal and inundation conditions, determining the need to restore hydrology, and addressing any pressure that may interfere with natural recruitment and regeneration [10].
Hydrological restoration, also considered a passive restoration method, is a form of Ecological Restoration (ER) whose purpose is to recover hydrological conditions by removing the factors that obstruct water flow in the degraded, damaged, or destroyed ecosystems in order to allow natural regeneration [1,4,10,11]. Being an Ecological Restoration method, hydrological restoration serves as an activator to initiate or accelerate and potentiate processes such as salinity stabilization and natural seed input, which results in the full natural recovery of a mangrove ecosystem [2,4,6,11]. This method is particularly effective when human manipulation and cyclone impact are the primary causes of degradation and the ecological conditions have been lost to such an extent that natural regeneration has become unfeasible [1]. This includes abandoned salt pan areas and rice fields, deforested areas where frequent exposure to solar radiation increased temperature and salinity, and areas affected by coastal development, dam construction, and the diversion of water courses [6].
The method has been extensively used in Mexico (Isla del Carmen located in Campeche, Sian Ka’an located in Quintana Roo, and Progreso, located in Yucatán) [4,6], Indonesia [1], and other parts of the world, but records of this method date back to 1930s, in the USA Delaware [12]. The method gained particular global attention in the field of coastal wetland restoration in the early 1930s and 2000s [10,13] due to its effectiveness and low cost, as it generally does not require the establishment of nurseries or the planting of seedlings or propagules, avoiding costs related to planting labor, transport [14], and associated equipment after implementation [15]. Moreover, by creating the adequate conditions for spontaneous seedling recruitment, this method produces a restored forest that is much more similar to a natural forest in terms of structure and functioning, instead of the silvicultural-like monospecific stands that planting produces [16,17]. Despite this, a widespread reluctance to move from the traditional planting persists in many mangrove restoration initiatives [16]. Additionally, progress in mangrove recovery after this type of intervention remains poorly documented, even when it is applied [18,19].
In Africa at large, and in the Western Indian Ocean (WIO) region in particular, the application of this method has barely been documented. However, it has been proven successful where it was tested [8]. This article documents the early outcomes of a hydrological restoration initiative carried out in northern Mozambique. The study is a concrete example of how ecological restoration approaches can be used to recover ecosystems that have been deeply degraded by natural and human factors, producing restored forests that are closer to natural ones.

2. Materials and Methods

2.1. Study Area

The Muanangome mangrove forest is located in the Mossuril District, Nampula province, in northern Mozambique (Figure 1). The population of the district is estimated at 203,727 inhabitants, with a density of 54 inhab/km2. The coastal population is highly dependent on natural resources for livelihood, and the main economic activities include fishing, tourism, agriculture, and informal trade.
The climate of the region is tropical humid and characterized by two seasons: a warm and rainy summer that starts in November and ends in April, with frequent rains and thunderstorms, in which the precipitation represents about 80% of the total annual precipitation [20,21], and a dry and cooler season that extends from May to October. The maximum temperature is 33.9 °C and the minimum is 19 °C, the average annual temperature is 25.5 °C, and the annual precipitation ranges between 600 and 1000 mm in the warm season (summer) [22,23]. Dominant winds in the region blow from east between January and March, and predominantly from the South between April and August. Between September and December, the winds predominantly blow from the east and southeast [22].
The tides are semi-diurnal with amplitudes of 110 cm during neap tides and 350 cm during spring tides [24].
Mangroves play an important role providing valuable resources, such as wood, firewood and animal protein to the communities. The forests are dominated by Avicenia marina, but other species such as Ceriops tagal, Rhizophora mucronata, S. alba, and L. racemosa also occur. Mangrove associates, Juncus kraussii, Cyperus articulatus, Typha latifolia and Salicornia sp. (Figure 2), dominated the landward margin of the forest in areas with high mangrove dieback. The presence of these species indicates low salinity in soil and water. The forest was also impacted by excessive logging, permanent freshwater flooding, channel blockage, conversion to salt pans and rice fields, sedimentation, and cyclone impacts [25]. The mangroves were restored in August of 2024, following a hydrological restoration approach, which consisted in the opening of 6.88 km of mangrove channel. Nineteen channels were opened manually, with community participation to reestablish tidal inundation in 38 ha of mangrove forest. Reference data covering pH, salinity, temperature, species composition and seedling density were collected prior to the intervention to allow for the identification of changes over time. The average soil/water salinity prior to restoration was 46.65 ± 7.44 PSU (Practical Salinity Unit), with the following differences across tidal range: upper zone—3.59 ± 1.13 PSU; lower zone—63.42 ± 7.50; middle zone—72.95 ± 5.02 PSU. The average pH before the intervention was 7.02 ± 0.17, distributed as 7.77 ± 0.08 in the lower zone, 6.63 ± 0.21 in the middle zone, and 6.67 ± 0.32 in the upper zone. The average temperature before the intervention was 30.43 ± 0.78 °C. With regards to regeneration, only Regeneration Class II (RCII) was found across all zones before the intervention.

2.2. Monitoring

Based on the site characteristics and mangrove species composition, the study area was divided into 3 zones across the tidal gradient and monitoring surveys were carried out in August 2024 prior to the intervention, and then in December 2024 and June 2025, 4 and 10 months after the intervention, respectively. Table 1 summarizes the biophysical characteristics of each zone, highlighting the differences.
Twenty-one independent 10 × 10 m plots were randomly set across the restored area, with 7 in each zone (Figure 3). Within each plot, soil salinity, pH and temperature were measured in porewater 30 to 40 cm deep using a Hanna HI98194 Multiparameter (Woonsocket, RI, EUA). All measurements were carried out in one day for each monitoring period during the low tide of a neap tide. Additionally, the number of wild seedlings per species and regeneration class was counted. The regenerating classes considered were as follows: regeneration class I (RCI)—seedlings up to 40 cm; RCII—sapling 40–150 cm; regeneration class III (RCIII)—small tree 150–300 cm. A visual assessment of the channels in the area was undertaken to assert maintenance needs.

2.3. Statistical Analysis

Statistical analysis was performed using software PAST 5.2.2, IBM SPSS Statistics 25 and RStudio 2022.02.2 + 485. Shapiro–Wilk and Levene testes were used to assess data normality and homogeneity of variances for seedling densities and environmental parameters. Average values of seedling density and environmental parameters were compared across the upper, middle and lower zones and through monitoring periods using two-way ANOVA for repeated measures. Then Post hoc Dunn tests were used to identify the distinct groups. Principal component analysis (PCA) was carried out, considering the environmental parameters to understand the spatial distribution of the three zones over time. This PCA was computed using a Correlation Matrix of the environmental parameters within each zone. Non-parametric analyses (Kruskal–Wallis) were used to compare seedling density across mangrove zones before and after restoration.

3. Results

3.1. Monitoring of Environmental Parameters

3.1.1. Salinity

In the first monitoring period, the average salinity was 38.14 ± 4.50 PSU; in the last monitoring period, it was 25.28 ± 3.98 PSU. This represented a reduction in salinity of 33.72% from the first to last monitoring and a reduction of 45.82% from the baseline value to the last monitoring.
The upper zone showed an increasing trend in salinity, with 19.23 ± 3.60 and 14.26 ± 6.32 PSU after 4 and 10 months. In contrast, salinity dropped after the intervention in the lower and middle zones, with mean values of 42.64 ± 7.77 PSU and 52.55 ± 5.61 PSU four months later, and 27.73 ± 7.28 PSU and 33.84 ± 5.63 PSU 10 months after the intervention, respectively (Table 2).
Two-way ANOVA revealed statistically significant differences in salinity when comparing averages per monitoring period [ANOVA: F(2,54) = 39.95, p < 0.0001] and mangrove zones [ANOVA: F(2,54) = 10.01, p = 0.0002].

3.1.2. pH

In the first and second monitoring periods, average pH values were similar at 6.81 ± 0.10 and 6.88 ± 0.13, respectively. After 4 months, mean pH decreased slightly in all mangrove zones, reaching 7.33 ± 0.09, 6.54 ± 0.06, and 6.56 ± 0.16 in the lower middle and upper zones, respectively. On the tenth month, there was another slight decrease in the mean pH in the lower zone, reaching 6.84 ± 0.09. Mean pH in the middle zone did not present any noticeable change, reaching 6.50 ± 0.13. Meanwhile, in the upper zone, mean pH increased to 7.30 ± 0.32 (Table 3).
Monitoring period had no statistically significant effect on pH [ANOVA: F(2,54) = 0.99, p = 0.3789]; in contrast, there was a significant effect of the zones on pH [ANOVA: F(2,54) = 12.54, p < 0.001].

3.1.3. Temperature (°C)

Overall, 4 and 10 months after the intervention, the average temperature was 32.99 ± 0.34 °C and 27.97 ± 0.40 °C, respectively.
In the lower zone, the mean temperature was high before the intervention, 32.78 °C and decreased to 27.06 °C on the tenth month. The middle zone showed an increase in mean temperature from the baseline value (28.12 °C) to 33.52 °C after 4 months, followed by a noticeable decrease to 28.40 °C after 10 months. The upper zone followed a similar pattern, with temperatures rising from 30.38 °C to 32.71 °C after 4 months, and then dropping to 27.93 °C after 10 months (Table 4).
The analysis revealed the significant effect of the monitoring period [ANOVA: F(2,54) = 26.40, p < 0.0001], with temporal changes in soil temperature across the sampling periods. However, there was no significant effect of zones [ANOVA: F(2,54) = 0.71, p = 0.4952]. Temporal changes in temperature were not uniform across zones. This was shown by the significant interaction between monitoring period and zones [ANOVA: F(4,54) = 3.64, p = 0.0107].

3.1.4. PCA

Principal component analysis (PCA) showcases a visual representation of the variations in the placement of the 3 zones, associated with the variations in salinity, pH and temperature after hydrological restoration. Prior to the intervention, there was clear separation between the zones with pronounced differences in salinity, with the upper zone standing out with very low salinity values (Figure 4A). Meanwhile, middle and lower zones clustered near the salinity and temperature vectors, reflecting the environmental gradient in these parameters. This gradient is showcased by the slight overlap in their figures.
Post-restoration, there was an increased overlap between all zones (Figure 4B). By June 2025, the PCA showed a trend towards the homogenization of the zones, with more evident overlap among the upper, middle, and lower zones, and less distinction along the salinity gradient (Figure 4C). This may reflect an improvement in hydrological connectivity and the gradual reentry of saltwater into previously isolated areas, especially in the upper zone.

3.2. Monitoring of Natural Regeneration

Seedling Density

Prior to the intervention, seedlings’ mean density was 57 ± 44 seedlings/ha. Four months later, mean density increased to 357 ± 212 seedlings/ha and then to 4864 ± 1779 seedlings/ha after 10 months.
The lower zone had no seedlings recorded before the intervention. Seedlings were observed 4 months after the intervention, with a mean density of 350 ± 350 seedlings/ha and a mean density of 2375 ± 1076 seedlings/ha after 10 months. Both middle and upper zone had low seedling density before the intervention, with 33 ± 33 and 150 ± 150 seedlings/ha. After 4 months, mean seedling density in the middle zone increased to 517 ± 458 seedlings/ha and there was a slightly decrease in the upper zone to 125 ± 75 seedlings/ha. The highest seeding density was recorded in the last monitoring period, at 6450 ± 3461 in the middle zone and 4975 ± 3679 seedlings/ha in the upper zone (Figure 5A).
There were no statistically significant differences when comparing seedling density across mangrove zones (Kruskal–Wallis: H(df = 2) = 0.135, n = 42, p = 0.935). However, seedlings density changed significantly with time (Kruskal–Wallis: H(df = 2) = 25.600, n = 42, p = 0.00), steadily increasing throughout all zones.
Seedling species composition also changed, as the middle and upper zones were initially monospecific with R. mucronata and A. marina, respectively. After 4 months, A. marina seedlings dominated all mangrove zones, comprising 100%, 93.5% and 100% of the seedlings in the lower, middle, and upper zones, respectively. Rhizophora mucronata seedlings were only found in the middle zone and comprised 6.5% of the total.
Ten months later, the number of recruiting species had increased from 2 to 3 in the middle zone, as L. racemosa now contributed with 0.5% of the seedlings (Figure 5B). The lower zone remained dominated by A. marina (87.4%), but two new species emerged, these being L. racemosa (5.3%) and S. alba (7.4%). In the upper zone (which had no regeneration prior to the intervention), A. marina remained the only species.
Changes were also observed when comparing regeneration classes. Four months after the intervention, RCI, which did not exist before restoration, was observed in all zones: 1400 ± 00 seedlings/ha (100%) in the lower zone; 1450 ± 1350 seedlings/ha (93.5%) in the middle zone; and 150 ± 50 seedlings/ha (33.3%) in the upper zone. Ten months later, RCI dominated all zones and RCIII was also observed in the upper zone. The upper zone had all 3 RCs (4750 ± 3555, 150 ± 50 and 600 ± 00 seedlings/ha corresponding to 95.5%, 1.5%, and 3% for RCI, RCII and RCIII, respectively); the middle zone had 5933 ± 3212 seedlings/ha for RCI and 1033 ± 884 saplings/ha for RCII, which corresponded to 92.0% and 8.0%, respectively (Figure 5C). The lower zone, which started with no seedlings, had 1620 ± 882 and 1400 ± 00 seedlings and saplings per hectare (RCI and RCII), corresponding to 85.3% and 14.7%, respectively.

4. Discussion

4.1. Mangrove Degradation and the Need for Hydrological Restoration

This study reports on the changes that occurred in a mangrove forest after an intervention to restore the hydrology of the site was undertaken. The study area had been impacted by river sedimentation that changed the local hydrology, blocking water passages, and causing permanent flooding in some areas while reducing tidal flooding in others. The local communities also reported that cyclone Gombe, which affected the area in 2022, brought new sediments to the mangrove and blocked natural channels, while also causing mechanical damage to the trees and consequently massive die back. Moreover, intense wood harvesting was reported at the site. These changes hindered forest natural regeneration, allowed the growth of competing species and exacerbated heterogeneity in the intertidal area (lower, middle and upper), as presented in Figure 4A.
Excessive sediment input is often associated with natural phenomena, such as cyclones, heavy rains, and even natural sedimentation patterns. Excessive sedimentation can be detrimental to mangroves due to the burial of roots and channel blockage, factors which are associated with altered flooding regimes and water stagnation [26,27,28]. Author [29] described similar changes in the mangrove of the State of Baja California Sur, Mexico, after a hurricane passed through Bahía de La Paz.
Stagnate sea water evaporates over time, increasing water and soil salinity to levels that are incompatible with mangrove growth [30,31]. Stagnated water is also rapidly oxygen-depleted as a result of the continued organic matter decomposition, creating anoxic conditions in the water and in the soil [32]. Such conditions quickly lead to the death of organisms, including mangrove fauna and flora. The subsequent organic matter decomposition under anoxic conditions produces toxic gases, such as hydrogen sulfide (H2S), methane (CH4, which is simultaneously a greenhouse gas) and ammonia (NH3) [33]. Water stagnation can also induce algal blooms. All these conditions lead to mangrove loss and degradation [34], if water circulation is not reestablished.
Healthy and structurally complex mangrove forests are capable of withstanding the impacts of cyclones and recovering to pre-cyclones conditions in a relatively short period of time [35,36,37]. However, unhealthy and frequently impacted forests may need longer periods to recover, and in some instances the damages may be permanent [35,38,39]. The northern Mozambique region has been impacted by at least 6 cyclones in the last 20 years (https://www.unocha.org/), some of which caused direct or indirect impacts to the mangroves. Climate change is altering the frequency and intensity of cyclones in many parts of the globe, and in Nampula province, there seems to be an increase in both frequency and intensity (Table 5). This may represent a big challenge to mangrove ecosystem conservation. Cyclone Gombe made landfall in Mossuril district in 2022. The category 3 cyclone had a maximum wind speed of 190 km/ha, and caused heavy rainfall of up to 200 mm in 24 h (Table 5). The strong winds and storm surges caused tree uprooting and mechanical damage to trees, including mangroves. The heavy rainfall also increased river flow and sediment input, which is consistent with the reported impact of heavy sedimentation and freshwater flooding in the mangroves. The total mangrove area impacted by cyclone Gombe is yet to be quantified. However, by evaluating the pre-intervention ecological conditions, this study shows how the cyclone potentially created significant changes along the forest gradient, even in an area as small as 38 ha.
Mangrove cutting reduced forest cover and created large canopy gaps that exposed the soil to solar radiation, increasing evaporation rate, changing its characteristics, and preventing forest regeneration [31,40,41,42,43]. However, when conducted on a small scale, mangrove logging can stimulate rapid forest regeneration and produce high-quality mangrove poles [44]. In the present study site, mangrove cutting did not seem sustainable, as trees were clear-cut in large extensions. In some instances, it also seemed that trees were cut after natural death driven by natural impacts.
The restoration method used in this study was also used to restore degraded mangrove forests in other locations [27,29,45,46,47,48]. The method was mainly used to recover mangrove areas impacted by tropical storms and hurricanes due to its effectiveness in recovering environmental parameters such as interstitial water salinity and natural recruitment within a year.

4.2. Environmental Parameters

By restoring the hydrology of the degraded mangrove, permanently flooded areas were drained (Figure 6A), while dry areas started to be regularly flooded. Regular but not permanent sea water flooding reduced the salinity in very saline areas, and increased the salinity in low-salinity areas, homogenizing the environmental conditions to be closer to those of a healthy mangrove forest. Ideal conditions also include pH, which ranged within normal mangrove values of between 5.6 and 9.4 [49].
PCA revealed that salinity was the main cause of variability of the areas, representing more than 80% to 90% of PC1 in all monitoring periods. Salinity was also the variable with the highest shift in the study area after the intervention.
Author [4] reported a reduction in salinity in two of four sites where monitoring took place after hydrological restoration. Opening channels in hydrological restoration allowed for constant water exchange within the mangrove, leading to changes in environmental parameters and interstitial water salinity [27]. These findings align with the results of the present study, where the reduction in salinity in the middle and lower zones of the restoration area was also recorded and estimated at around 28% to 35% after 4 months and at over 50% after 10 months when making comparisons to the initial measurements. This reduction in salinity after hydrological restoration was also reported by [27,46] in the mangroves of Laguna de Terminos, Campeche, in the Gulf of Mexico. Author [46] reported low levels of salinity, observing 49 PSU against 55 PSU in the reference sites after restoring the hydrology in degraded mangroves following tropical storms and hurricanes.
Moreover, mangrove competitive species (e.g., Juncus kraussii, Typha latifolia and Salicornia sp.) were completely wiped out in most of the mangrove areas as the ideal conditions for mangrove growth were reestablished (Figure 6B).

4.3. Seed Recruitment and Natural Regeneration

Soil and water salinity is key for mangrove forest natural regeneration. In general, seedlings show optimum growth at salinities between 5 and 20 PSU, but some species can cope with salinity levels up to 35 PSU [50,51]. In the present study, the density and species richness of seedlings increased significantly after the hydrological restoration, a trend that was reported for other sites [45]. Opened channels in the restored area brought seeds and propagules from other areas, which then recruited and germinated in the most suitable sites in the upper, middle and lower areas [45,47]. The increase in natural recruitment was in general above 100% compared to natural regeneration in August 2024 before hydrological restoration. Author [29] also find similar results regarding the tendency of recruitment increase after restoring the hydrology of a degraded mangrove in State of Baja California Sur, Mexico, after a hurricane that moved large sand dunes blocking the sole outlet channel of mangroves. In the year after their intervention, they found the occurrence of mangrove recruitment, and reported an increase of 409% over the vegetation compared to one year (2004) before the intervention.
Avicennia marina had the highest density of recruitment in all zones compared to other species, similar to what [46] found for Avicennia germinans. This result was explained by the small size of the seeds and propagules of this species, features that allow them to be carried away easily by waters during low and high tides.
Seedlings of Lumnitzera racemosa (adult trees only occurred in the lower zone) were observed in the middle zone 10 months after the intervention (Figure 7), reinforcing the idea that the artificial channels reestablished the connectivity between zones, and that such connectivity is key for ecosystem diversity and health [45,52].
The increase in seedling density in the study site was remarkable, and remained stable despite the occurrence of cyclones Chido (December 2024) and Diikeledi (January 2025) [53,54]. Both events caused severe destruction in the province’s infrastructure, and negatively impacted the reproductive cycle of mangrove species, particularly A. marina, whose seed maturation period matched with cyclone landfall [25]. Local communities also reported loss of seedlings and damage in mangrove nurseries [55]. Given this, it seems reasonable to believe that seedling density could be much higher without the cyclones, and that wild seedlings from hydrological restoration are resilient to extreme climatic events, because only the fittest seed germinates, and only at the best spots in the forest [10,45].
Before the hydrological restoration, the regeneration potential in all zones was far from the minimum ecological ratio for mangrove forest regeneration of 6:3:1 (for RCI:RCII:RCIII), as described by [56]. In the upper and middle zones, regeneration was restricted to saplings (0:1:0), with no seedlings or young trees. There was no regeneration at all in the lower zone (0:0:0), reflecting severe environmental constraints, likely associated with excessive salinity. Shortly after the intervention, a positive response in natural regeneration was recorded, particularly in the middle zone, where the proportion shifted to 15:1:0. The upper zone also showed improvement (1:2:0), while the lower zone exhibited an initial recovery (1:0:0) with A. marina seedlings. In the upper zone, the regeneration ratio reached 63:1:1, indicating the massive recruitment of seedlings and the first occurrence of young trees, suggesting the beginning of structural maturity of the new plants. The middle and lower zones maintained high seedling abundance ratios (11:1:0) and (6:1:0), respectively, but lacked young trees.

5. Conclusions

The hydrological restoration implemented in Muanangome has shown clear ecological benefits within a relatively short time frame. Restoration efforts effectively reduced salinity levels, improved soil pH, and stabilized the temperature, enhancing drainage in the middle and lower zones. These changes created more favorable conditions for seedling establishment and survival, directly supporting natural regeneration processes. The expansion of Lumnitzera racemosa seedlings to new areas further indicates that hydrological restoration facilitated seed dispersal and forest connectivity. The progressive emergence of RCIII individuals in the upper zone also suggests early signs of structural maturation in the forest. This hydrological reconnection contributed to a more balanced distribution of species and regeneration classes across the landscape, a critical component in the resilience and long-term stability of the ecosystem. Given the positive results of this project, we recommend the wider use of hydrological restoration for mangrove restoration in the country and in the WIO region. The method should be included in more mangrove restoration guidelines, which should bring more cases of success and encourage the use of this method when planting does not seem to be appropriate.

Author Contributions

A.d.J.F.—Conceptualization; Data collection and field work implementation; Monitoring; Data Curation and data analysis; Writing—Original Draft Preparation; Visualization H.B.—Methodology, Field work implementation, Writing—Original Draft Preparation; M.A.C.—Data collection and field work implementation; Monitoring. F.C.—Data collection and field work implementation; Monitoring. C.d.C.M.—Conceptualization; Methodology, Writing—Original Draft Preparation; Supervision; Writing—Review & Editing; Project Coordination; Resources and Funding Acquisition. All authors have read and agreed to the published version of the manuscript.

Funding

The project is primarily funded by the Blue Action Fund, grant nr. 06_22_22-27_WCS_MZ (supported by the Green Climate Fund), Oceans 5, Margaret A. Cargill Philanthropies, and Bloomberg Philanthropies.

Data Availability Statement

Data presented in this study are available on request from the corresponding author.

Acknowledgments

This study was conducted within the framework of the Blue Future Project—Building a Blue Future for Ecosystems and People on the East African Coast (https://wcsbluefuture.com/en/, accessed on 2 May 2026), implemented by the WCS Mozambique. This study also forms part of the main author’s MSc dissertation and the scholarship supporting his program of study is funded by BIOFUND through the PLCM—Programa de Liderança para a Conservação de Moçambique.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Djamaluddin, R.; Brown, B.; Lewis, R., III. The Practice of Hydrological Restoration to Rehabilitate Abandoned Shrimp Ponds in Bunaken National Park, North Sulawesi, Indonesia. Biodiversitas 2019, 20, 160–170. [Google Scholar] [CrossRef]
  2. Ruiz-Guevara, S.M.; Quintero-Castañeda, C.Y.; Hernández-Angulo, L.R.; Sierra-Carrillo, M.M. Environmental Psychology and Mangrove Reforestation in the Ciénaga Grande de Santa Marta, Colombia: An Approach to Ecosystem Restoration. World 2025, 6, 24. [Google Scholar] [CrossRef]
  3. Esguerra-Rodríguez, D.; De León-Lorenzana, A.; Teutli, C.; Prieto-Davó, A.; García-Maldonado, J.Q.; Herrera-Silveira, J.; Falcón, L.I. Do Restoration Strategies in Mangroves Recover Microbial Diversity? A Case Study in the Yucatan Peninsula. PLoS ONE 2024, 19, e0307929. [Google Scholar] [CrossRef] [PubMed]
  4. Pérez-Ceballos, R.; Zaldívar-Jiménez, A.; Canales-Delgadillo, J.; López-Adame, H.; López-Portillo, J.; Merino-Ibarra, M. Determining Hydrological Flow Paths to Enhance Restoration in Impaired Mangrove Wetlands. PLoS ONE 2020, 15, e0227665. [Google Scholar] [CrossRef] [PubMed]
  5. Balidy, H.J.; Bandeira, S.O.; Macamo, C.d.C.F.; Mechisso, M.; Laissone, J. Community-Based Mangrove Restoration: The Cases of the Limpopo Estuary and Quelimane Municipality. In Proceedings of the 11th WIOMSA Scientific Symposium, Reduit, Mauritius, 8–13 July 2019; Available online: https://symposium.wiomsa.org/wp-content/uploads/2019/06/551-906-1-SM.pdf (accessed on 23 June 2025).
  6. Teutli-Hernández, C.; Herrera-Silveira, J.A.; Cisneros de la Cruz, D.; Roman-Cuesta, R.M. Mangrove Ecological Restoration Guide: Lessons Learned; Mainstreaming Wetlands into the Climate Agenda: A multilevel approach (SWAMP); CIFOR/CINVESTAV-IPN/UNAM-Sisal/PMC: Mexico City, Mexico, 2020. [Google Scholar] [CrossRef]
  7. Preferred by Nature. Ecosystem Restoration. Report for Eden Reforestation Projects; Sofala Province, Mozambique. 2022. Available online: https://www.preferredbynature.org/sites/default/files/publicsummaries/Eden%20Reforestation%20Projects%20Sofala%20ER%20ver%2022%20-%20PS_0.pdf (accessed on 3 March 2025).
  8. Bandeira, S.; Balidy, H. Limpopo Estuary Mangrove Transformation, Rehabilitation and Management. In Estuaries: A Lifeline of Ecosystem Services in the Western Indian Ocean; Diop, S., Scheren, P., Ferdinand Machiwa, J., Eds.; Springer International Publishing: Cham, Switzerland, 2016; pp. 227–237. ISBN 978-3-319-25370-1. [Google Scholar] [CrossRef]
  9. Gatt, Y.M.; Walton, R.W.; Andradi-Brown, D.A.; Spalding, M.D.; Acosta-Velázquez, J.; Adame, M.F.; Barros, F.; Beeston, M.A.; Bernardino, A.F.; Buelow, C.A.; et al. The Mangrove Restoration Tracker Tool: Meeting Local Practitioner Needs and Tracking Progress toward Global Targets. One Earth 2024, 7, 2072–2085. [Google Scholar] [CrossRef]
  10. Lewis, R.R., III. Ecological Engineering for Successful Management and Restoration of Mangrove Forests. Wetl. Creat. 2005, 24, 403–418. [Google Scholar] [CrossRef]
  11. Beeston, M.; Cameron, C.; Hagger, V.; Howard, J.; Lovelock, C.; Sippo, C.; Tonnejk, F.; van Bijsterveldt, C.; van Eijk, P. (Eds.) Best Practice Guidelines for Mangrove Restoration; Global Mangrove Alliance: Arlington, VA, USA, 2023; Available online: https://www.mangrovealliance.org/best-practice-guidelines-for-mangrove-restoration/ (accessed on 4 April 2025).
  12. Turner, R.E.; Lewis, R.R. Hydrologic Restoration of Coastal Wetlands. Wetl. Ecol. Manag. 1996, 4, 65–72. [Google Scholar] [CrossRef]
  13. Rivera-Monroy, V.; Lee, S.; Kristensen, E.; Twilley, R. Mangrove Ecosystems: A Global Biogeographic Perspective: Structure, Function, and Services; Springer: Berlin/Heidelberg, Germany, 2017; ISBN 978-3-319-62204-0. [Google Scholar]
  14. Kairo, J.G.; Mangora, M. Guidelines on Mangrove Ecosystem Restoration for the Western Indian Ocean Region Western Indian Ocean Region; United Nations Environment: Nairobi, Kenya, 2020; ISBN 2714-1942. Available online: https://www.nairobiconvention.org/CHM%20Documents/WIOSAP/guidelines/GuidelinesonMangroveRestorationForTheWIO.pdf (accessed on 13 March 2025).
  15. Glamore, W.; Rayner, D.; Ruprecht, J.; Sadat-Noori, M.; Khojasteh, D. Eco-Hydrology as a Driver for Tidal Restoration: Observations from a Ramsar Wetland in Eastern Australia. PLoS ONE 2021, 16, e0254701. [Google Scholar] [CrossRef] [PubMed]
  16. Wodehouse, D.C.J.; Rayment, M.B. Mangrove Area and Propagule Number Planting Targets Produce Sub-Optimal Rehabilitation and Afforestation Outcomes. Estuar. Coast. Shelf Sci. 2019, 222, 91–102. [Google Scholar] [CrossRef]
  17. Ferreira, A.C.; Freire, F.A.M.; Rodrigues, J.V.M.; Bezerra, L.E.A. Mangrove Recovery in Semiarid Coast Shows Increase of Ecological Processes from Biotic and Abiotic Drivers in Response to Hydrological Restoration. Wetlands 2022, 42, 80. [Google Scholar] [CrossRef]
  18. Rodríguez-Rodríguez, J.A.; Mancera-Pineda, J.E.; Tavera, H. Mangrove Restoration in Colombia: Trends and Lessons Learned. For. Ecol. Manag. 2021, 496, 119414. [Google Scholar] [CrossRef]
  19. Gerona-Daga, M.E.B.; Salmo, S.G. A Systematic Review of Mangrove Restoration Studies in Southeast Asia: Challenges and Opportunities for the United Nation’s Decade on Ecosystem Restoration. Front. Mar. Sci. 2022, 9, 987737. [Google Scholar] [CrossRef]
  20. Impacto Projecto de Avaliação Ambiental Estratégica Da Zona Costeira—Moçambique: Perfil Ambiental e Mapeamento Do Uso Actual Da Terra Nos Distritos Da Zona Costeira de Moçambique, Distrito de Memba, Província de Nampula; Ministério para a Coordenação da Acção Ambiental. 2012. Available online: https://biblioteca.biofund.org.mz/wp-content/uploads/2019/01/1547471892-Perfil_Memba.pdf (accessed on 7 March 2025).
  21. Impacto Projecto de Avaliação Ambiental Estratégica Da Zona Costeira—Moçambique: Perfil Ambiental e Mapeamento Do Uso Actual Da Terra Nos Distritos Da Zona Costeira de Moçambique, Distrito de Mossuril, Província de Nampula; Ministério para a Coordenação da Acção Ambiental. 2012. Available online: https://biblioteca.biofund.org.mz/wp-content/uploads/2019/01/1547473677-Perfil_Mossuril.pdf (accessed on 7 March 2025).
  22. Ministry of Sea, Inland Waters and Fisheries (MIMAIP). Coastal and Marine. Ecosystems Restoration Assessment-Coastal Resilience to Climate Change (CRCC) Baseline; IUCN, MIMAIP, RARE. 2019. Available online: https://www.researchgate.net/profile/Ndoli-Alain-2/publication/343933717_Coastal_and_Marine_restoration_Baseline_Report_-_Mozambique/links/5f48b54492851c6cfdef59a1/Coastal-and-Marine-restoration-Baseline-Report-Mozambique.pdf (accessed on 23 March 2026).
  23. Zacarias, D.A. Understanding Community Vulnerability to Climate Change and Variability at a Coastal Municipality in Southern Mozambique. Int. J. Clim. Chang. Strateg. Manag. 2018, 11, 154–176. [Google Scholar] [CrossRef]
  24. Sete, C.; Rudy, J.; Dove, V. Seasonal Variation of Tides, Currents, Salinity and Temperature Along the Coast of Mozambique; National Oceanographic Data Center—CENADO, 2022; Available online: https://www.researchgate.net/publication/277201551_Seasonal_variation_of_tides_currents_salinity_and_temperature_along_the_coast_of_Mozambique (accessed on 3 April 2025).
  25. Rodrigues, M. Mozambique Prisoner to a Vicious Cycle of Post-Cyclone Reconstruction and Losses. 2025. Available online: https://www.cipmoz.org/wp-content/uploads/2025/05/Mozambique-Prisoner-to-a-Vicious-Cycle.pdf (accessed on 27 March 2026).
  26. Ngole-Jeme, V.M.; Fonge, B.A.; Tabot, P.T.; Mumbang, C. Impact of Logging Activities in a Tropical Mangrove on Ecosystem Diversity and Sediment Heavy Metal Concentrations. J. Coast. Conserv. 2016, 20, 245–255. [Google Scholar] [CrossRef]
  27. López-Adame, H.; Zaragoza-Méndez, F.Á.; Lara-Domínguez, A.L.; Alvarado-Barrientos, M.S.; Mariño-Tapia, I.; Sáinz-Hernández, E.; Pérez-Ceballos, R.; Zaldívar-Jiménez, A.; López-Portillo, J. Effectiveness of Hydrological Restoration in the Mangrove of a Coastal Lagoon in the Gulf of Mexico. Ecol. Eng. 2026, 223, 107848. [Google Scholar] [CrossRef]
  28. Medina, E.; Cuevas, E.; Popp, M.; Lugo, A. Soil Salinity, Sun Exposure, and Growth of Acrostichum Aureum, the Mangrove Fern. Bot. Gaz. 1990, 151, 41–49. [Google Scholar] [CrossRef]
  29. Bashan, Y.; Moreno, M.; Salazar, B.G.; Alvarez, L. Restoration and Recovery of Hurricane-Damaged Mangroves Using the Knickpoint Retreat Effect and Tides as Dredging Tools. J. Environ. Manag. 2013, 116, 196–203. [Google Scholar] [CrossRef] [PubMed]
  30. Medina-Calderón, J.H.; Mancera-Pineda, J.E.; Castañeda-Moya, E.; Rivera-Monroy, V.H. Hydroperiod and Salinity Interactions Control Mangrove Root Dynamics in a Karstic Oceanic Island in the Caribbean Sea (San Andres, Colombia). Front. Mar. Sci. 2021, 7, 598132. [Google Scholar] [CrossRef]
  31. Ahmed, S.; Sarker, S.K.; Friess, D.A.; Kamruzzaman, M.; Jacobs, M.; Islam, M.A.; Alam, M.A.; Suvo, M.J.; Sani, M.N.H.; Dey, T.; et al. Salinity Reduces Site Quality and Mangrove Forest Functions. From Monitoring to Understanding. Sci. Total Environ. 2022, 853, 158662. [Google Scholar] [CrossRef] [PubMed]
  32. Monsalve, E.R.; Vergara, L.V. Water and Sediment Quality Changes in Mangrove Systems with Shrimp Farms in the Northern Ecuadorean Coast. Appl. Sci. 2023, 13, 7749. [Google Scholar] [CrossRef]
  33. Sánchez-Carrillo, S.; Garatuza-Payan, J.; Sánchez-Andrés, R.; Cervantes, F.J.; Bartolomé, M.C.; Merino-Ibarra, M.; Thalasso, F. Methane Production and Oxidation in Mangrove Soils Assessed by Stable Isotope Mass Balances. Water 2021, 13, 1867. [Google Scholar] [CrossRef]
  34. Radabaugh, K.R.; Dontis, E.E.; Chappel, A.R.; Russo, C.E.; Moyer, R.P. Early Indicators of Stress in Mangrove Forests with Altered Hydrology in Tampa Bay, Florida, USA. Estuar. Coast. Shelf Sci. 2021, 254, 107324. [Google Scholar] [CrossRef]
  35. Blankespoor, B.; Dasgupta, S.; Lange, G.-M. Mangroves as a Protection from Storm Surges in a Changing Climate. Ambio 2017, 46, 478–491. [Google Scholar] [CrossRef] [PubMed]
  36. Herrera-Silveira, J.A.; Hernandez, C.; Secaira Fajardo, F.; Braun, R.; Bowman, J.; Geselbracht, L.; Musgrove, M.; Rogers, M.; Schmidt, J.; Toral, P.; et al. Hurricane Damages to Mangrove Forests and Post-Storm Restoration Techniques and Costs; The Nature Conservancy: Arlington, VA, USA, 2022. [Google Scholar] [CrossRef]
  37. Sunkur, R.; Kantamaneni, K.; Bokhoree, C.; Ravan, S. Mangroves’ Role in Supporting Ecosystem-Based Techniques to Reduce Disaster Risk and Adapt to Climate Change: A Review. J. Sea Res. 2023, 196, 102449. [Google Scholar] [CrossRef]
  38. Macamo, C.C.F.; Massuanganhe, E.; Nicolau, D.K.; Bandeira, S.O.; Adams, J.B. Mangrove’s Response to Cyclone Eline (2000): What Is Happening 14 Years Later. Aquat. Bot. 2016, 134, 10–17. [Google Scholar] [CrossRef]
  39. Asbridge, E.; Krause, C.; Lucas, R.; Owers, C.J.; Rogers, K.; Lymburner, L.; Mueller, N.; Ai, E.; Wong, S. Characterising the Short- and Long-Term Impacts of Tropical Cyclones on Mangroves Using the Landsat Archive. Camb. Prism. Coast. Futures 2025, 3, e4. [Google Scholar] [CrossRef] [PubMed]
  40. Ellis, W.L.; Bell, S.S. Canopy Gaps Formed by Mangrove Trimming: An Experimental Test of Impact on Litter Fall and Standing Litter Stock in Southwest Florida (USA). J. Exp. Mar. Biol. Ecol. 2004, 311, 201–222. [Google Scholar] [CrossRef]
  41. Alongi, D.M.; de Carvalho, N.A. The Effect of Small-Scale Logging on Stand Characteristics and Soil Biogeochemistry in Mangrove Forests of Timor Leste. For. Ecol. Manag. 2008, 255, 1359–1366. [Google Scholar] [CrossRef]
  42. Simon, L.; Raffaelli, D. Assessing Ecosystem Effects of Small–Scale Cutting of Cameroon Mangrove Forests. J. Ecol. Nat. Environ. 2012, 4, 126–134. [Google Scholar] [CrossRef]
  43. Ahidjo, S.; Hayatou, E.; Ayang, P. Evaluating the Outcomes of Small–Scale Cutting of Mangrove Forests in the Ecosystem. Afr. J. Ecol. Ecosyst. 2015, 2, 95–102. [Google Scholar]
  44. Murdiyarso, D.; Sasmito, S.D.; Sillanpää, M.; MacKenzie, R.; Gaveau, D. Mangrove Selective Logging Sustains Biomass Carbon Recovery, Soil Carbon, and Sediment. Sci. Rep. 2021, 11, 12325. [Google Scholar] [CrossRef] [PubMed]
  45. Teutli-Hernández, C.; Herrera-Silveira, J.A.; Comín, F.A.; López, M.M. Nurse Species Could Facilitate the Recruitment of Mangrove Seedlings after Hydrological Rehabilitation. Ecol. Eng. 2019, 130, 263–270. [Google Scholar] [CrossRef]
  46. Echeverría-ávila, S.; Pérez-Ceballos, R.; Zaldívar-Jiménez, A.; Canales-Delgadillo, J.; Brito-Pérez, R.; Merino-Ibarra, A.; Vovides, A. Regeneración natural de sitios de manglar degradado en respuesta a la restauración hidrológica. Madera Bosques 2019, 25, e2511754. [Google Scholar] [CrossRef]
  47. Su, C.J.; Hsieh, S.-Y.; Chiang, M.W.-L.; Pang, K.-L. Salinity, PH and Temperature Growth Ranges of Halophytophthora Isolates Suggest Their Physiological Adaptations to Mangrove Environments. Mycology 2020, 11, 256–262. [Google Scholar] [CrossRef] [PubMed]
  48. Bandeira, S.O.; Macamo, C.d.C.F.; Mahazule, R.; Mabilana, H. Estudo de Lições Aprendidas e Boas Práticas de Reabilitação Do Mangal. Avaliação Do Programa de Restauração de Mangal No Estuário Do Limpopo (Gaza), Tsolombane Em Matutuine (Maputo), Nhangau (Sofala), Inhassunge e Macuze (Zambézia) e Mecúfi e Metuge (Cabo Delgado); Biofund: Maputo, Moçambique, 2016. [Google Scholar]
  49. Muttaqin, A.D.; Soemarno, S.; Purnomo, M.; Zakiyah, U. Analysis of the Mangrove Ecosystem Due to the Influence of Mount Bromo’s Cold Lava Material on Permata Pilang Beach, Probolinggo. Ecol. Eng. Environ. Technol. 2024, 25, 272–281. [Google Scholar] [CrossRef] [PubMed]
  50. Chen, Y.; Ye, Y. Effects of Salinity and Nutrient Addition on Mangrove Excoecaria agallocha. PLoS ONE 2014, 9, e93337. [Google Scholar] [CrossRef] [PubMed]
  51. de Silva, W.; Amarasinghe, M. Response of Mangrove Plant Species to a Saline Gradient: Implications for Ecological Restoration. Acta Bot. Bras. 2021, 35, 151–160. [Google Scholar] [CrossRef]
  52. Numbere, A.O. Natural Seedling Recruitment and Regeneration in Deforested and Sand-Filled Mangrove Forest at Eagle Island, Niger Delta, Nigeria. Ecol. Evol. 2021, 11, 3148–3158. [Google Scholar] [CrossRef] [PubMed]
  53. National Institute for Disaster Risk Management and Reduction (INGD). Balanço Da Época Chuvosa e Ciclónica 2023/2024. 2024. Available online: https://ingd.gov.mz/wp-content/uploads/2025/07/Relatorio_do_Balanco_da_ECC_2023-2024-.pdf (accessed on 7 March 2025).
  54. National Institute for Disaster Risk Management and Reduction (INGD). PLANO ANUAL DE CONTINGÊNCIA 2025-202. 2025. Available online: https://ingd.gov.mz/wp-content/uploads/2025/10/PC-2025-26-CM.pdf (accessed on 12 March 2025).
  55. Amade, U. (Mangrove Nursery Operator, Geba, Memba district, Mozambique). Personal communication, 2025.
  56. FAO. Mangrove Forest Management Guidelines; Forest Resources Development Branch, Forest Resources Division FAO Forestry Department M-36, Publications Division, Food and Agriculture Organization of the United Nations: Rome, Italy, 1994; Available online: https://www.fao.org/4/ap428e/ap428e00.pdf (accessed on 7 March 2025).
Diversity 18 00385 g001
Figure 1. Geographic location of the study area. Blue line Shows the contour of the restoration site in the mangrove forest of Muanangome. Made in ArcGIS Pro 3.4.0 by Alberto Fernando.
Figure 1. Geographic location of the study area. Blue line Shows the contour of the restoration site in the mangrove forest of Muanangome. Made in ArcGIS Pro 3.4.0 by Alberto Fernando.
Diversity 18 00385 g001
Diversity 18 00385 g002
Figure 2. Images from different sites in the degraded mangrove in Muanangome before Hydological restoration. Photos ® Alberto Fernando.
Figure 2. Images from different sites in the degraded mangrove in Muanangome before Hydological restoration. Photos ® Alberto Fernando.
Diversity 18 00385 g002
Diversity 18 00385 g003
Figure 3. Main mangrove zones defined in the study area. Made in ArcGIS Pro 3.4.0 by Alberto Fernando.
Figure 3. Main mangrove zones defined in the study area. Made in ArcGIS Pro 3.4.0 by Alberto Fernando.
Diversity 18 00385 g003
Diversity 18 00385 g004
Figure 4. Graphs show the ordering of samples from the upper, middle and lower zones within in the orthogonal space of the PCA (A) before hydrological restoration, (B) 4 months after the intervention and (C) 10 months after the intervention.
Figure 4. Graphs show the ordering of samples from the upper, middle and lower zones within in the orthogonal space of the PCA (A) before hydrological restoration, (B) 4 months after the intervention and (C) 10 months after the intervention.
Diversity 18 00385 g004
Diversity 18 00385 g005
Figure 5. Seedling mean density in the upper, middle and lower zones (mean ± se). Total density (A), species density (B), and regeneration class density (C).
Figure 5. Seedling mean density in the upper, middle and lower zones (mean ± se). Total density (A), species density (B), and regeneration class density (C).
Diversity 18 00385 g005
Diversity 18 00385 g006
Figure 6. Photos of the degraded mangrove forest before hydrological restoration (left) and the changes after the artificial channels were opened (right). Photos ® Alberto Fernando.
Figure 6. Photos of the degraded mangrove forest before hydrological restoration (left) and the changes after the artificial channels were opened (right). Photos ® Alberto Fernando.
Diversity 18 00385 g006
Diversity 18 00385 g007
Figure 7. Representation of the distribution of mangrove seedlings per species after hydrological restoration in the upper middle and lower zones (solid arrows—distribution of seedlings in the same zone occupied by the adult trees), and the expansion of Lumnitzera racemosa from the lower to the middle zone (dashed arrow—distribution of seedlings in zones different from those occupied by the adult trees).
Figure 7. Representation of the distribution of mangrove seedlings per species after hydrological restoration in the upper middle and lower zones (solid arrows—distribution of seedlings in the same zone occupied by the adult trees), and the expansion of Lumnitzera racemosa from the lower to the middle zone (dashed arrow—distribution of seedlings in zones different from those occupied by the adult trees).
Diversity 18 00385 g007
Table 1. Main characteristics of the three mangrove zones in the restoration area.
Table 1. Main characteristics of the three mangrove zones in the restoration area.
ZonesCharacteristics
Upper
  • Salinity: 0 PSU to 30 PSU.
  • Soil: sand and clay, firm to soft.
  • Mangrove species: A. marina.
  • Other characteristics: dominated by associated species Typha latifolia and Cyperus sp.; river influence and stagnation of fresh water.
Middle
  • Salinity: 50 PSU to above 100 PSU.
  • Soil: sand and clay, firm to soft.
  • Mangrove species: A. marina, R. mucronata and S. alba.
  • Other characteristics: intensive logging, canopy gaps; high density of associated species Juncus kraussii and Salicornia sp.; stagnant fresh and salt water.
Lower
  • Salinity: 50 PSU to 100 PSU.
  • Soil: sandy, firm to soft.
  • Mangrove species: A. marina, C. tagal, R. mucronata, S. alba and L. racemosa.
  • Other characteristics: intensive logging, canopy gaps.
Table 2. Mean salinity variation over the monitoring periods within the three mangrove zones.
Table 2. Mean salinity variation over the monitoring periods within the three mangrove zones.
ZonesBaselineMonitorings
August 2024December 2024June 2025
Lower63.42 ± 7.50 (a,1)42.64 ± 7.7727.73 ± 7.28 (a)
Middle72.95 ± 5.02 (b,2)52.55 ± 5.61 (3)33.84 ± 5.63 (b)
Upper3.59 ± 1.13 (c,1,2)19.23 ± 3.60 (c,3)14.26 ± 6.32
a,b,c Statistically dissimilar monitoring periods (Dunn post hoc: p < 0.05) within zones. 1,2,3 Statistically dissimilar zones (Dunn post hoc: p < 0.05).
Table 3. Mean pH variation over the monitoring periods within the three mangrove zones.
Table 3. Mean pH variation over the monitoring periods within the three mangrove zones.
ZonesBaselineMonitorings
August 2024 December 2024 June 2025
Lower7.77 ± 0.08 (1,2)7.33 ± 0.09 (3,4)6.84 ± 0.09
Middle6.63 ± 0.21 (1)6.54 ± 0.06 (3)6.50 ± 0.13
Upper6.67 ± 0.32 (2)6.56 ± 0.16 (4)7.30 ± 0.32
1,2,3,4 Statistically dissimilar zones (Dunn post hoc: p < 0.05).
Table 4. Mean temperature variation over the monitoring periods within the three mangrove zones.
Table 4. Mean temperature variation over the monitoring periods within the three mangrove zones.
ZonesBaselineMonitorings
August 2024December 2024June 2025
Lower32.78 ± 1.15 (a)32.73 ± 0.6127.06 ± 0.94 (a)
Middle28.12 ± 1.17 (b)33.52 ± 0.56 (b,c)28.40 ± 0.44
Upper30.38 ± 1.2732.71 ± 0.64 (d)27.93 ± 0.62 (d)
a,b,c,d Statistically dissimilar monitoring periods (Dunn post hoc: p < 0.05) within zones.
Table 5. Cyclones that made landfall in Nampula province 2008 to 2025. Source: https://www.unocha.org (accessed on 23 January 2026); https://mozambique.unfpa.org/ (accessed on 23 January 2026); https://ingd.gov.mz/relatorio-das-epocas-chuvosas/ (accessed on 23 January 2026).
Table 5. Cyclones that made landfall in Nampula province 2008 to 2025. Source: https://www.unocha.org (accessed on 23 January 2026); https://mozambique.unfpa.org/ (accessed on 23 January 2026); https://ingd.gov.mz/relatorio-das-epocas-chuvosas/ (accessed on 23 January 2026).
Cyclone, YearCategory (Saffir-Simpson Scale)CharacteristicsMain Impacts Nampula Province (Mozambique)
JOKWE, March 20081—Tropical cycloneLandfall site: Nampula Province, between Nacala and Moz. Island
GOMBE, March 20223—Tropical cycloneWind speeds up to 190 km/h; 200 mm in 24 h
Most affected areas: Mozambique island, Lunga		Affected 642,383 people, 53 deaths and 77 injured; over 23,994 people displaced; damages to electricity infrastructure; 707 km of road impacted. Damage estimated at USD 81.9 million.
CHIDO, December 20244-equivalent—Tropical cycloneWind speeds up to 120 km/h and reaching 260 km/h; 250 mm in 24 h
Most affected areas: Cabo Delgado, Nampula and Niassa		Affected 175,169 people, 493 injured and 45 people dead (37 in Cabo Delgado, 5 in Nampula and 3 in Niassa)
DIKELEDI, January 20252—Tropical cycloneWind speed: 150 km/ha up to 180 km/h; 210.4 to 247 mm
Most affected areas: Nampula Province, between Nacala Porto and Liupo		Affected 283,333 people, 48 heath facilities, 221 schools
JUDE, March 20251—HurricaneWind speed: 120 km/ha; more than 200 mm in 24 h
Most affected areas: Nampula Province between Memba and Mossuril		Affected over 390,000 people, 13 deaths, 135 injured; 81 health facilities, 272 schools, 18 bridges, 48 water systems, and 73 km of electricity lines.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Fernando, A.d.J.; Balidy, H.; Cuambe, M.A.; César, F.; Macamo, C.d.C. Ecological Restoration of Mangrove Forests: Early Ecological Responses to Hydrological Restoration in Eastern Africa. Diversity 2026, 18, 385. https://doi.org/10.3390/d18060385

AMA Style

Fernando AdJ, Balidy H, Cuambe MA, César F, Macamo CdC. Ecological Restoration of Mangrove Forests: Early Ecological Responses to Hydrological Restoration in Eastern Africa. Diversity. 2026; 18(6):385. https://doi.org/10.3390/d18060385

Chicago/Turabian Style

Fernando, Alberto de Jesus, Henriques Balidy, Maria Alberto Cuambe, Faustino César, and Célia da Conceição Macamo. 2026. "Ecological Restoration of Mangrove Forests: Early Ecological Responses to Hydrological Restoration in Eastern Africa" Diversity 18, no. 6: 385. https://doi.org/10.3390/d18060385

APA Style

Fernando, A. d. J., Balidy, H., Cuambe, M. A., César, F., & Macamo, C. d. C. (2026). Ecological Restoration of Mangrove Forests: Early Ecological Responses to Hydrological Restoration in Eastern Africa. Diversity, 18(6), 385. https://doi.org/10.3390/d18060385

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop