J. Kairo - Academia.edu (original) (raw)
Papers by J. Kairo
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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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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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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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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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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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Ecology and Evolution, 2014
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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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Western Indian Ocean Journal of Marine Science, 2009
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... 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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Ocean & Coastal Management, 2011
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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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Marine Ecology Progress Series, 2008
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
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.
Bookmarks Related papers MentionsView impact
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
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
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...
Bookmarks Related papers MentionsView impact
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...
Bookmarks Related papers MentionsView impact
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
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Ecology and Evolution, 2014
Bookmarks Related papers MentionsView impact
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
Bookmarks Related papers MentionsView impact
Western Indian Ocean Journal of Marine Science, 2009
Bookmarks Related papers MentionsView impact
... 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
Bookmarks Related papers MentionsView impact
Ocean & Coastal Management, 2011
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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
Marine Ecology Progress Series, 2008
Bookmarks Related papers MentionsView impact