Mangrove cover and cover change analysis in the transboundary area of Kenya and Tanzania during 1986–2016

Mungai, Fredrick; Kairo, James Gitundu; Mironga, John Momanyi; Kirui, Bernard; Mangora, Mwita M.; Koedam, Nico

doi:10.1080/19480881.2019.1613868

Cited by 14 publications

(21 citation statements)

References 17 publications

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“…At the southern coast of Kenya, mangroves are dominated by mixed species stands (Mungai et al, 2019), with near pristine Rhizophora dominated stands on Sii Island at the southern-most part of the country (GoK, 2017). Human-induced losses and degradation of mangroves in Kenya have been widely reported (Kirui et al, 2013;Bosire et al, 2014;GoK, 2017;Mungai et al, 2019).…”

Section: Additional Field Datamentioning

confidence: 99%

Stocks and Productivity of Dead Wood in Mangrove Forests: A Systematic Literature Review

Mugi

Kiss

Kairo

et al. 2022

Front. For. Glob. Change

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The functional and ecological importance of dead wood in terrestrial forests is widely recognized and researched. In contrast, much less is known about dead wood in mangrove forests, despite its known or demonstrated contribution to key ecological processes including nutrient cycling and seedling recruitment. In addition, mangrove dead wood provides an important service for millions of people; harvesting wood for fuel is widespread in mangroves and is often vital for the lives and wellbeing of people living close to these forests. Limited information on stocks and production, and the drivers of these, means that understanding and managing the supply of this service is difficult. Here we conduct a systematic review of the literature on dead wood stocks and production in mangrove ecosystems. Four hundred and seventy-five subject articles were found, with large gaps in geography, species, and forest type. After excluding records that were not relevant to our study and those from mass mortality events, 68 studies remained. We also added new data from 9 sites in Kenya, to provide overall estimates of mean (± SD) stocks of dead wood of 16.85 ± 25.35 Mg ha−1 standing and 29.92 ± 36.72 Mg ha−1 downed. Our analysis shows that potentially, higher stocks of dead wood might be found in forests without evidence of human impact. Average mean production with 95% CI was 6.30, 3.10–11.40 Mg ha−1 yr−1. Estimates of daily wood use were applied to give likely demands on wood from mangrove dependent communities. This review reveals the paucity of research on mangrove dead wood, hence these estimates of average stocks and productivity remain very limited and thus, further work on the dynamics of dead wood in mangroves and the ecological effects of its removal is needed.

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Section: Additional Field Datamentioning

confidence: 99%

Stocks and Productivity of Dead Wood in Mangrove Forests: A Systematic Literature Review

Mugi

Kiss

Kairo

et al. 2022

Front. For. Glob. Change

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“…Use of remotely sensed data and Geographical Information Systems (GIS) is a common practice in estimating forest cover and cover change; including mangroves (Polidoro et al, 2010;Giri et al, 2011;Kirui et al, 2013;Thomas et al, 2017;Mungai et al, 2019). Mapping of mangroves is challenged by their low spatial extent when compared to terrestrial forests, the cloudy nature associated with coastal areas, as well as problems linked to poor species discrimination (Thomas et al, 2017;Mungai et al, 2019). In the current study, Landsat imagery dating from 1990 were accessed and reviewed for quality and cloud-free scenes.…”

Section: Mapping Mangrove Cover/and Cover Changementioning

confidence: 99%

Total Ecosystem Carbon Stocks of Mangroves in Lamu, Kenya; and Their Potential Contributions to the Climate Change Agenda in the Country

Kairo

Mbatha

Murithi

et al. 2021

Front. For. Glob. Change

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Mangroves are carbon-rich ecosystems found in tropical and subtropical areas around the world. However, they are threatened by a combination of natural and human-induced factors. When mangroves are lost or degraded, their co-benefits to human society are greatly diminished along with the ecosystem’s ability to sequester carbon. The current study assessed mangrove cover and cover change, as well as measuring carbon stocks and their emissions levels from the mangroves of Lamu County, Kenya. We sampled above-and below-ground carbon pools, including soil organic carbon (SOC), in 191 plots distributed throughout the study area. Lastly, we evaluated the economics of avoiding mangrove deforestation based on the carbon-offset market. The total carbon stock of mangroves in Lamu was estimated at 20 million Mg C, with an average density of 560.22 ± 79.79 Mg C ha–1. Southern swamps recorded significantly higher carbon densities (p < 0.05) than other mangrove management blocks in Lamu. At least 1,739 ha of mangroves in Lamu were lost between 1990 and 2019 due to anthropogenic activities, representing a decline of 60 ha yr–1. Total emissions from loss and degradation of mangroves in Lamu is estimated at 140.1 Mg C ha–1; which translates to 30,840.1 Mg CO2e yr–1. Assuming an offset price of US$10/Mg CO2e, the estimated costs of avoided emissions in Lamu is US$308,401 yr–1 plus other co-benefits such as fishery functions and shoreline protection. Mainstreaming mangroves and associated blue carbon ecosystems into national development and climate change agenda could accelerate Kenya’s achievements of both Sustainable Development Goals (SDGs) and the Paris Agreement.

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“…To our knowledge, no in-situ data has been collected or studies on vertical accretion or surface elevation change done within the mangroves of Vanga (Kenya). Most studies in and around the mangroves of Vanga have focused more on fisheries, water quality, mangrove structure and socioeconomics (Ochiewo et al, 2010;Kiteresi et al, 2012;Mungai et al, 2019;Fortnam et al, 2020;Kimani et al, 2020). The mangroves of Vanga have suffered a significant loss of cover than other adjacent mangrove areas in Kenya and Tanzania (Mungai et al, 2019) and within the proposed transboundary conservation area (Figure 3).…”

Section: Introductionmentioning

confidence: 99%

“…Most studies in and around the mangroves of Vanga have focused more on fisheries, water quality, mangrove structure and socioeconomics (Ochiewo et al, 2010;Kiteresi et al, 2012;Mungai et al, 2019;Fortnam et al, 2020;Kimani et al, 2020). The mangroves of Vanga have suffered a significant loss of cover than other adjacent mangrove areas in Kenya and Tanzania (Mungai et al, 2019) and within the proposed transboundary conservation area (Figure 3). Due to observed losses, Vanga has been designated as a hotspot of mangrove loss, with an average annual loss of 25 ha (Mungai et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…The mangroves of Vanga have suffered a significant loss of cover than other adjacent mangrove areas in Kenya and Tanzania (Mungai et al, 2019) and within the proposed transboundary conservation area (Figure 3). Due to observed losses, Vanga has been designated as a hotspot of mangrove loss, with an average annual loss of 25 ha (Mungai et al, 2019). This change has been attributed to anthropogenic activities, including harvesting and land-use changes.…”

Section: Introductionmentioning

confidence: 99%

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Surface elevation changes in an estuarine mangrove forest in Vanga, Kenya: Implications for management and mitigation of sea-level rise

et al. 2022

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Mangrove ecosystems are often called “makers of land” due to their ability to promote deposition, trap, and augment sediments. Accurate location- and region-specific elevation information is required to assess and mitigate threats to mangroves caused by their vulnerability to sea-level rise. The provision of land building services by mangroves is primarily sediment-dependent. It is therefore influenced by local factors, including sediment availability and supply. In the present study from Kenya, we measured and examined the variations in surface elevation in mangroves at variable distances from the creek channel using a combination of surface-elevation tables and horizon markers for three years. Elevation changes varied with distance from the creek channel (p < 0.05), with both surface loss and gains recorded. Elevation changes varied between -80 mm (most significant subsidence) and 42 mm (highest accretion) in stations closer to the creek, while farther from the creek (~200 m away), elevation changes ranged between -68 mm (most significant subsidence) and 29 mm (highest accretion). However, net surface elevation changes over the three years showed that shallow subsidence occurred in both stations closer to the creek (-45 ± 7.2 mm) and those farthest from the creek (-20 ± 7.1 mm). At the same time, an average of 18 mm of sediments were accreted above the horizon markers translating to ~9 mm yr-1 of accretion, a rate larger than both the current global rates of sea-level rise (~3.1 mm yr-1) and local measured rates of sea-level rise (3.8 mm yr-1) in Mombasa, a tide-gauge station nearest (~100 km) to the study site. Cumulatively, sediment elevation changes in Vanga indicate that they are outpacing the current rates of sea-level rise. However, they could be vulnerable to predicted and accelerated rates. It, therefore, calls for more holistic management and monitoring of the dynamics within the mangrove forests and adjacent terrestrial hinterlands.

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Mangrove cover and cover change analysis in the transboundary area of Kenya and Tanzania during 1986–2016

Cited by 14 publications

References 17 publications

Stocks and Productivity of Dead Wood in Mangrove Forests: A Systematic Literature Review

Stocks and Productivity of Dead Wood in Mangrove Forests: A Systematic Literature Review

Total Ecosystem Carbon Stocks of Mangroves in Lamu, Kenya; and Their Potential Contributions to the Climate Change Agenda in the Country

Surface elevation changes in an estuarine mangrove forest in Vanga, Kenya: Implications for management and mitigation of sea-level rise

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