J. Kairo - Academia.edu (original) (raw)

Papers by J. Kairo

Research paper thumbnail of Mangroves

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Research paper thumbnail of Turning the Tide: How Blue Carbon and Payments for Ecosystem Services (PES) Might Help Save Mangrove Forests

AMBIO, 2014

In this review paper, we aim to describe the potential for, and the key challenges to, applying P... more In this review paper, we aim to describe the potential for, and the key challenges to, applying PES projects to mangroves. By adopting a "carbocentric approach," we show that mangrove forests are strong candidates for PES projects. They are particularly well suited to the generation of carbon credits because of their unrivaled potential as carbon sinks, their resistance and resilience to natural hazards, and their extensive provision of Ecosystem Services other than carbon sequestration, primarily nursery areas for fish, water purification and coastal protection, to the benefit of local communities as well as to the global population. The voluntary carbon market provides opportunities for the development of appropriate protocols and good practice case studies for mangroves at a small scale, and these may influence larger compliance schemes in the future. Mangrove habitats are mostly located in developing countries on communally or state-owned land. This means that issues of national and local governance, land ownership and management, and environmental justice are the main challenges that require careful planning at the early stages of mangrove PES projects to ensure successful outcomes and equitable benefit sharing within local communities.

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Research paper thumbnail of Comparative Study of the Disjunct Zonation Pattern of the Grey Mangrove Avicennia Marina (FORSK.) Vierh. In Gazi Bay (Kenya)

The disjunct zonation pattern of Avicennia marina (Forsk.) Vierh., frequently ob- served along th... more The disjunct zonation pattern of Avicennia marina (Forsk.) Vierh., frequently ob- served along the Kenyan coast as a landward and a seaward zone, has been studied on a morphological level and complemented with preliminary genetic data. The objective was to describe the two zones in-depth in order to provide a background ecological set- ting that may be used in explanations

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Research paper thumbnail of Faunal and floral secondary succession in a restored mangrove system in Kenya

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Research paper thumbnail of Colonization of non-planted mangroves into reforested mangrove stands

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Research paper thumbnail of Ecology and Restoration of Mangrove Systems in Kenya

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Research paper thumbnail of How to catch the patch? A dendrometer study of the radial increment through successive cambia in the mangrove Avicennia

Annals of botany, 2014

Successive vascular cambia are involved in the secondary growth of at least 200 woody species fro... more Successive vascular cambia are involved in the secondary growth of at least 200 woody species from >30 plant families. In the mangrove Avicennia these successive cambia are organized in patches, creating stems with non-concentric xylem tissue surrounded by internal phloem tissue. Little is known about radial growth and tree stem dynamics in trees with this type of anatomy. This study aims to (1) clarify the process of secondary growth of Avicennia trees by studying its patchiness; and (2) study the radial increment of Avicennia stems, both temporary and permanent, in relation to local climatic and environmental conditions. A test is made of the hypothesis that patchy radial growth and stem dynamics enable Avicennia trees to better survive conditions of extreme physiological drought. Methods Stem variations were monitored by automatic point dendrometers at four different positions around and along the stem of two Avicennia marina trees in the mangrove forest of Gazi Bay (Kenya) du...

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Research paper thumbnail of Influence of a salinity gradient on the vessel characters of the mangrove species Rhizophora mucronata

Annals of botany, 2006

Although mangroves have been extensively studied, little is known about their ecological wood ana... more Although mangroves have been extensively studied, little is known about their ecological wood anatomy. This investigation examined the potential use of vessel density as a proxy for soil water salinity in the mangrove species Rhizophora mucronata (Rhizophoraceae) from Kenya. In a time-standardized approach, 50 wood discs from trees growing in six salinity categories were investigated. Vessel densities, and tangential and radial diameters of rainy and dry season wood of one distinct year, at three positions on the stem discs, were measured. A repeated-measures ANOVA with the prevailing salinity was performed. Vessel density showed a significant increase with salinity, supporting its use as a prospective measure of salinity. Interestingly, the negative salinity response of the radial diameter of vessels was less striking, and tangential diameter was constant under the varying environmental conditions. An effect of age or growth rate or the presence of vessel dimorphism could be exclud...

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Research paper thumbnail of Growth rings, growth ring formation and age determination in the mangrove Rhizophora mucronata

Annals of botany, 2004

The mangrove Rhizophora mucronata has previously been reported to lack annual growth rings, thus ... more The mangrove Rhizophora mucronata has previously been reported to lack annual growth rings, thus barring it from dendrochronological studies. In this study the reported absence of the growth rings was reconsidered and the periodic nature of light and dark brown layers visible on polished stem discs investigated. In addition, the formation of these layers in relation to prevailing environmental conditions, as well as their potential for age determination of the trees, was studied. Trees of known age were collected and a 2.5-year cambial marking experiment was conducted to determine the periodic nature of the visible growth layers. Annual indistinct growth rings were detected in R. mucronata and are defined by a low vessel density earlywood and a high vessel density latewood. The formation of these growth rings and their periodic nature was independent from site-specific environmental conditions in two forests along the Kenyan coast. However, the periodic nature of the rings was serio...

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Research paper thumbnail of Exploitation of mangrove wood products from a subsistence perspective: a case-study in Mida Creek

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Research paper thumbnail of Testing mangrove forest structure development and various forest management options in Gazi (Kenya) by combining KiWi individual-based modelling with> 20 years of field data

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Research paper thumbnail of Effects of experimental sedimentation on the phenological dynamics and leaf traits of replanted mangroves at Gazi bay, Kenya

Ecology and Evolution, 2014

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Research paper thumbnail of A patchy growth via successive and simultaneous cambia: Key to success of the most widespread mangrove species Avicennia marina?

Annals of Botany, 2008

Secondary growth via successive cambia has been intriguing researchers for decades. Insight into ... more Secondary growth via successive cambia has been intriguing researchers for decades. Insight into the mechanism of growth layer formation is, however, limited to the cellular level. The present study aims to clarify secondary growth via successive cambia in the mangrove species Avicennia marina on a macroscopic level, addressing the formation of the growth layer network as a whole. In addition, previously suggested effects of salinity on growth layer formation were reconsidered. A 1-year cambial marking experiment was performed on 80 trees from eight sites in two mangrove forests in Kenya. Environmental (soil water salinity and nutrients, soil texture, inundation frequency) and tree characteristics (diameter, height, leaf area index) were recorded for each site. Both groups of variables were analysed in relation to annual number of growth layers, annual radial increment and average growth layer width of stem discs. Between trees of the same site, the number of growth layers formed during the 1-year study period varied from only part of a growth layer up to four growth layers, and was highly correlated to the corresponding radial increment (0-5 mm year(-1)), even along the different sides of asymmetric stem discs. The radial increment was unrelated to salinity, but the growth layer width decreased with increasing salinity and decreasing tree height. A patchy growth mechanism was proposed, with an optimal growth at distinct moments in time at different positions around the stem circumference. This strategy creates the opportunity to form several growth layers simultaneously, as observed in 14 % of the studied trees, which may optimize tree growth under favourable conditions. Strong evidence was provided for a mainly endogenous trigger controlling cambium differentiation, with an additional influence of current environmental conditions in a trade-off between hydraulic efficiency and mechanical stability.

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Research paper thumbnail of Mangroves in peril: unprecedented degradation rates of peri-urban mangroves in Kenya

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Research paper thumbnail of Spatial and Temporal Regeneration Dynamics in Ceriops tagal ( Perr.) C.B. Rob. (Rhizophoraceae) Mangrove Forests in Kenya

Western Indian Ocean Journal of Marine Science, 2009

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Research paper thumbnail of How sustainable is the utilization of mangrove products in peri-urban Mombasa, Kenya?

... Publication Mohamed, MOS, Kairo, JG, Dahdouh-Guebas, F. and Koedam N. 2008. ... Ecologically,... more ... Publication Mohamed, MOS, Kairo, JG, Dahdouh-Guebas, F. and Koedam N. 2008. ... Ecologically, mangroves are spawning grounds for fish, as well as feeding habitats and runways of numerous migratory birds (Nagelkerken et al., 2000; Ellison, 2008a; ...

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Research paper thumbnail of Spatial macrobenthic variations in a tropical mangrove Bay

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Research paper thumbnail of Mapping of mangrove forest land cover change along the Kenya coastline using Landsat imagery

Ocean & Coastal Management, 2011

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Research paper thumbnail of Success rates of recruited tree species and their contribution to the structural development of reforested mangrove stands

Marine Ecology Progress Series, 2006

... MATERIALS AND METHODS Study site. This study was conducted at Gazi Bay (Fig. 1) on the southe... more ... MATERIALS AND METHODS Study site. This study was conducted at Gazi Bay (Fig. 1) on the southern coast of Kenya in 2 mono-specific reforested mangrove stands (Sonneratia alba J. Smith and Rhizophora mucronata Lamk), which were both 8 yr old. ... Floristic composition. ...

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Research paper thumbnail of Digital terrain modelling to investigate the effects of sea level rise on mangrove propagule establishment

Marine Ecology Progress Series, 2008

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Research paper thumbnail of Mangroves

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Research paper thumbnail of Turning the Tide: How Blue Carbon and Payments for Ecosystem Services (PES) Might Help Save Mangrove Forests

AMBIO, 2014

In this review paper, we aim to describe the potential for, and the key challenges to, applying P... more In this review paper, we aim to describe the potential for, and the key challenges to, applying PES projects to mangroves. By adopting a "carbocentric approach," we show that mangrove forests are strong candidates for PES projects. They are particularly well suited to the generation of carbon credits because of their unrivaled potential as carbon sinks, their resistance and resilience to natural hazards, and their extensive provision of Ecosystem Services other than carbon sequestration, primarily nursery areas for fish, water purification and coastal protection, to the benefit of local communities as well as to the global population. The voluntary carbon market provides opportunities for the development of appropriate protocols and good practice case studies for mangroves at a small scale, and these may influence larger compliance schemes in the future. Mangrove habitats are mostly located in developing countries on communally or state-owned land. This means that issues of national and local governance, land ownership and management, and environmental justice are the main challenges that require careful planning at the early stages of mangrove PES projects to ensure successful outcomes and equitable benefit sharing within local communities.

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Research paper thumbnail of Comparative Study of the Disjunct Zonation Pattern of the Grey Mangrove Avicennia Marina (FORSK.) Vierh. In Gazi Bay (Kenya)

The disjunct zonation pattern of Avicennia marina (Forsk.) Vierh., frequently ob- served along th... more The disjunct zonation pattern of Avicennia marina (Forsk.) Vierh., frequently ob- served along the Kenyan coast as a landward and a seaward zone, has been studied on a morphological level and complemented with preliminary genetic data. The objective was to describe the two zones in-depth in order to provide a background ecological set- ting that may be used in explanations

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Faunal and floral secondary succession in a restored mangrove system in Kenya

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Colonization of non-planted mangroves into reforested mangrove stands

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Ecology and Restoration of Mangrove Systems in Kenya

Bookmarks Related papers MentionsView impact

Research paper thumbnail of How to catch the patch? A dendrometer study of the radial increment through successive cambia in the mangrove Avicennia

Annals of botany, 2014

Successive vascular cambia are involved in the secondary growth of at least 200 woody species fro... more Successive vascular cambia are involved in the secondary growth of at least 200 woody species from >30 plant families. In the mangrove Avicennia these successive cambia are organized in patches, creating stems with non-concentric xylem tissue surrounded by internal phloem tissue. Little is known about radial growth and tree stem dynamics in trees with this type of anatomy. This study aims to (1) clarify the process of secondary growth of Avicennia trees by studying its patchiness; and (2) study the radial increment of Avicennia stems, both temporary and permanent, in relation to local climatic and environmental conditions. A test is made of the hypothesis that patchy radial growth and stem dynamics enable Avicennia trees to better survive conditions of extreme physiological drought. Methods Stem variations were monitored by automatic point dendrometers at four different positions around and along the stem of two Avicennia marina trees in the mangrove forest of Gazi Bay (Kenya) du...

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Research paper thumbnail of Influence of a salinity gradient on the vessel characters of the mangrove species Rhizophora mucronata

Annals of botany, 2006

Although mangroves have been extensively studied, little is known about their ecological wood ana... more Although mangroves have been extensively studied, little is known about their ecological wood anatomy. This investigation examined the potential use of vessel density as a proxy for soil water salinity in the mangrove species Rhizophora mucronata (Rhizophoraceae) from Kenya. In a time-standardized approach, 50 wood discs from trees growing in six salinity categories were investigated. Vessel densities, and tangential and radial diameters of rainy and dry season wood of one distinct year, at three positions on the stem discs, were measured. A repeated-measures ANOVA with the prevailing salinity was performed. Vessel density showed a significant increase with salinity, supporting its use as a prospective measure of salinity. Interestingly, the negative salinity response of the radial diameter of vessels was less striking, and tangential diameter was constant under the varying environmental conditions. An effect of age or growth rate or the presence of vessel dimorphism could be exclud...

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Research paper thumbnail of Growth rings, growth ring formation and age determination in the mangrove Rhizophora mucronata

Annals of botany, 2004

The mangrove Rhizophora mucronata has previously been reported to lack annual growth rings, thus ... more The mangrove Rhizophora mucronata has previously been reported to lack annual growth rings, thus barring it from dendrochronological studies. In this study the reported absence of the growth rings was reconsidered and the periodic nature of light and dark brown layers visible on polished stem discs investigated. In addition, the formation of these layers in relation to prevailing environmental conditions, as well as their potential for age determination of the trees, was studied. Trees of known age were collected and a 2.5-year cambial marking experiment was conducted to determine the periodic nature of the visible growth layers. Annual indistinct growth rings were detected in R. mucronata and are defined by a low vessel density earlywood and a high vessel density latewood. The formation of these growth rings and their periodic nature was independent from site-specific environmental conditions in two forests along the Kenyan coast. However, the periodic nature of the rings was serio...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Exploitation of mangrove wood products from a subsistence perspective: a case-study in Mida Creek

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Testing mangrove forest structure development and various forest management options in Gazi (Kenya) by combining KiWi individual-based modelling with> 20 years of field data

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Effects of experimental sedimentation on the phenological dynamics and leaf traits of replanted mangroves at Gazi bay, Kenya

Ecology and Evolution, 2014

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A patchy growth via successive and simultaneous cambia: Key to success of the most widespread mangrove species Avicennia marina?

Annals of Botany, 2008

Secondary growth via successive cambia has been intriguing researchers for decades. Insight into ... more Secondary growth via successive cambia has been intriguing researchers for decades. Insight into the mechanism of growth layer formation is, however, limited to the cellular level. The present study aims to clarify secondary growth via successive cambia in the mangrove species Avicennia marina on a macroscopic level, addressing the formation of the growth layer network as a whole. In addition, previously suggested effects of salinity on growth layer formation were reconsidered. A 1-year cambial marking experiment was performed on 80 trees from eight sites in two mangrove forests in Kenya. Environmental (soil water salinity and nutrients, soil texture, inundation frequency) and tree characteristics (diameter, height, leaf area index) were recorded for each site. Both groups of variables were analysed in relation to annual number of growth layers, annual radial increment and average growth layer width of stem discs. Between trees of the same site, the number of growth layers formed during the 1-year study period varied from only part of a growth layer up to four growth layers, and was highly correlated to the corresponding radial increment (0-5 mm year(-1)), even along the different sides of asymmetric stem discs. The radial increment was unrelated to salinity, but the growth layer width decreased with increasing salinity and decreasing tree height. A patchy growth mechanism was proposed, with an optimal growth at distinct moments in time at different positions around the stem circumference. This strategy creates the opportunity to form several growth layers simultaneously, as observed in 14 % of the studied trees, which may optimize tree growth under favourable conditions. Strong evidence was provided for a mainly endogenous trigger controlling cambium differentiation, with an additional influence of current environmental conditions in a trade-off between hydraulic efficiency and mechanical stability.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Mangroves in peril: unprecedented degradation rates of peri-urban mangroves in Kenya

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Spatial and Temporal Regeneration Dynamics in Ceriops tagal ( Perr.) C.B. Rob. (Rhizophoraceae) Mangrove Forests in Kenya

Western Indian Ocean Journal of Marine Science, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of How sustainable is the utilization of mangrove products in peri-urban Mombasa, Kenya?

... Publication Mohamed, MOS, Kairo, JG, Dahdouh-Guebas, F. and Koedam N. 2008. ... Ecologically,... more ... Publication Mohamed, MOS, Kairo, JG, Dahdouh-Guebas, F. and Koedam N. 2008. ... Ecologically, mangroves are spawning grounds for fish, as well as feeding habitats and runways of numerous migratory birds (Nagelkerken et al., 2000; Ellison, 2008a; ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Spatial macrobenthic variations in a tropical mangrove Bay

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Mapping of mangrove forest land cover change along the Kenya coastline using Landsat imagery

Ocean & Coastal Management, 2011

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Success rates of recruited tree species and their contribution to the structural development of reforested mangrove stands

Marine Ecology Progress Series, 2006

... MATERIALS AND METHODS Study site. This study was conducted at Gazi Bay (Fig. 1) on the southe... more ... MATERIALS AND METHODS Study site. This study was conducted at Gazi Bay (Fig. 1) on the southern coast of Kenya in 2 mono-specific reforested mangrove stands (Sonneratia alba J. Smith and Rhizophora mucronata Lamk), which were both 8 yr old. ... Floristic composition. ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Digital terrain modelling to investigate the effects of sea level rise on mangrove propagule establishment

Marine Ecology Progress Series, 2008

Bookmarks Related papers MentionsView impact