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  1. Article ; Online: Where to fish in the forest? Tree characteristics and contiguous seagrass features predict mangrove forest quality for fishes and crustaceans

    Wanjiru, Caroline / Nagelkerken, Ivan / Rueckert, Sonja / Harcourt, William / Huxham, Mark

    Journal of Applied Ecology. 2023 July, v. 60, no. 7 p.1340-1351

    2023  

    Abstract: Mangroves often support rich fish and crustacean communities, although faunal abundance and diversity show strong spatiotemporal variability. Consistent patterns in mangrove animal communities might be dictated by forest characteristics, by seascape ... ...

    Abstract Mangroves often support rich fish and crustacean communities, although faunal abundance and diversity show strong spatiotemporal variability. Consistent patterns in mangrove animal communities might be dictated by forest characteristics, by seascape context or by some combination of these factors. Predicting drivers of spatial heterogeneity in mangrove faunal communities can better support the zoning of forests for management purposes, for example by identifying sites important for fisheries nursery provision. We sampled 14 sites within a large (4000 ha) mangrove forest in Kenya, quarterly over a period of 2 years. There were clear and consistent differences in the quality of sites for fish and crustacean abundance and diversity. Forest characteristics (as summarised by the complexity index, CI) and seascape metrics (the presence, area and configuration of contiguous seagrass) were strong predictors of site differences. However, they showed opposite influences on dominant members of the fish and crustacean faunas, with CI correlated negatively with fishes and positively with crustaceans, and seagrass area correlated positively with fishes and negatively with crustaceans. Synthesis and applications. Sites within the same mangrove forest exhibit consistent differences in fish and crustacean abundance. However, the fish and crustacean communities (and particularly dominant species within them) act differently in response to forest and seascape characteristics. Old growth, mature forest, set in a seascape of seagrass patches with bare sediment, was associated with highest crustacean abundance. In contrast, denser smaller trees and seascapes with larger, continuous areas of seagrass correlated better with fish abundance. Zoning for management, as mandated in new Kenyan policy, will need to consider these differences in seascape use between fish and crustaceans.
    Keywords Crustacea ; applied ecology ; dominant species ; fauna ; fish ; issues and policy ; mangrove forests ; seagrasses ; sediments ; spatial variation ; Kenya
    Language English
    Dates of publication 2023-07
    Size p. 1340-1351.
    Publishing place John Wiley & Sons, Ltd
    Document type Article ; Online
    Note JOURNAL ARTICLE
    ZDB-ID 410405-5
    ISSN 1365-2664 ; 0021-8901
    ISSN (online) 1365-2664
    ISSN 0021-8901
    DOI 10.1111/1365-2664.14421
    Database NAL-Catalogue (AGRICOLA)

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  2. Article ; Online: Point of (no) return? Vegetation structure and diversity of restored mangroves in Sulawesi, Indonesia, 14–16 years on

    Djamaluddin, Rignolda / Fusi, Marco / Djabar, Brama / Evans, Darren / Holmes, Rachael / Huxham, Mark / O'Connell, Darren P. / Salzmann, Ulrich / Singleton, I. / Tjoa, Aiyen / Trianto, Agus / Diele, Karen

    Restoration Ecology. 2023 Sept., v. 31, no. 7 p.e13963-

    2023  

    Abstract: Mangrove forests, benefitting millions of people, experience significant degradation. Global recognition of the urgency of halting and reversing this trend have initiated numerous restoration activities. Restoration success is typically evaluated by ... ...

    Abstract Mangrove forests, benefitting millions of people, experience significant degradation. Global recognition of the urgency of halting and reversing this trend have initiated numerous restoration activities. Restoration success is typically evaluated by estimating mangrove survival and area restored, while diversity and structure of vegetation, as proxies for functional forests, are rarely considered. Here we assess mangrove species richness along sea‐landward transects and evaluate restoration outcomes by comparing number of mangrove species, relative species abundance, biomass, diameter, and canopy cover in “Monoculture Reforestation”, “Mixed Species Regeneration” and adjacent “Reference” forest stands, 14 (Tiwoho site) and 16 years (Likupang site) after restoration activities took place. In the “Monoculture Reforestation” plots, mangrove diversity and structure still closely reflected the original restoration actions, with only one and two “new” species having established among the originally densely planted “foundation” species. In contrast, the “Mixed Species Regeneration” plots were more similar to the “Reference” plots in terms of tree diameter and canopy coverage, but species number, abundance and biomass were still lower. The trajectory of the “Mixed Species Regeneration” plots suggests their similarity with the “Reference” stands will increase over time, whereas such “smooth” transition is unlikely to happen in the planted “Monoculture Reforestation” stands, in the foreseeable future. Implementing frequent small‐scale disturbances in restored forest management would increase stand structure and diversity, accelerating the establishment of a more natural, and likely more functional and resilient forest.
    Keywords biomass ; canopy ; ecological restoration ; forest management ; forests ; species abundance ; species richness ; stand structure ; tree and stand measurements ; Indonesia
    Language English
    Dates of publication 2023-09
    Publishing place Wiley Periodicals, Inc.
    Document type Article ; Online
    Note JOURNAL ARTICLE
    ZDB-ID 914746-9
    ISSN 1526-100X ; 1061-2971
    ISSN (online) 1526-100X
    ISSN 1061-2971
    DOI 10.1111/rec.13963
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  3. Article ; Online: The thin(ning) green line? Investigating changes in Kenya's seagrass coverage.

    Harcourt, William D / Briers, Robert A / Huxham, Mark

    Biology letters

    2018  Volume 14, Issue 11

    Abstract: Knowledge of seagrass distribution is limited to a few well-studied sites and poor where resources are scant (e.g. Africa), hence global estimates of seagrass carbon storage are inaccurate. Here, we analysed freely available Sentinel-2 and Landsat ... ...

    Abstract Knowledge of seagrass distribution is limited to a few well-studied sites and poor where resources are scant (e.g. Africa), hence global estimates of seagrass carbon storage are inaccurate. Here, we analysed freely available Sentinel-2 and Landsat imagery to quantify contemporary coverage and change in seagrass between 1986 and 2016 on Kenya's coast. Using field surveys and independent estimates of historical seagrass, we estimate total cover of Kenya's seagrass to be 317.1 ± 27.2 km
    MeSH term(s) Alismatales ; Aquatic Organisms ; Conservation of Natural Resources ; Kenya ; Plant Dispersal
    Language English
    Publishing date 2018-11-28
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2135022-X
    ISSN 1744-957X ; 1744-9561
    ISSN (online) 1744-957X
    ISSN 1744-9561
    DOI 10.1098/rsbl.2018.0227
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Multiple impact pathways of the 2015–2016 El Niño in coastal Kenya

    Fortnam, Matt / Atkins, Molly / Brown, Katrina / Chaigneau, Tomas / Frouws, Ankje / Gwaro, Kemyline / Huxham, Mark / Kairo, James / Kimeli, Amon / Kirui, Bernard / Sheen, Katy

    Ambio. 2021 Jan., v. 50, no. 1

    2021  

    Abstract: The 2015–2016 El Niño had large impacts globally. The effects were not as great as anticipated in Kenya, however, leading some commentators to call it a ‘non-event’. Our study uses a novel combination of participatory Climate Vulnerability and Capacity ... ...

    Abstract The 2015–2016 El Niño had large impacts globally. The effects were not as great as anticipated in Kenya, however, leading some commentators to call it a ‘non-event’. Our study uses a novel combination of participatory Climate Vulnerability and Capacity Analysis tools, and new and existing social and biophysical data, to analyse vulnerability to, and the multidimensional impacts of, the 2015–2016 El Niño episode in southern coastal Kenya. Using a social-ecological systems lens and a unique dataset, our study reveals impacts overlooked by conventional analysis. We show how El Niño stressors interact with and amplify existing vulnerabilities to differentially impact local ecosystems and people. The policy significance of this finding is that the development of specific national capacities to deal with El Niño events is insufficient; it will be necessary to also address local vulnerabilities to everyday and recurrent stressors and shocks to build resilience to the effects of El Niño and other extremes in climate and weather.
    Keywords El Nino ; climate ; data collection ; issues and policy ; people ; Kenya
    Language English
    Dates of publication 2021-01
    Size p. 174-189.
    Publishing place Springer Netherlands
    Document type Article
    Note NAL-AP-2-clean
    ZDB-ID 120759-3
    ISSN 1654-7209 ; 0044-7447
    ISSN (online) 1654-7209
    ISSN 0044-7447
    DOI 10.1007/s13280-020-01321-z
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  5. Article ; Online: Carbon storage in the seagrass meadows of Gazi Bay, Kenya.

    Githaiga, Michael N / Kairo, James G / Gilpin, Linda / Huxham, Mark

    PloS one

    2017  Volume 12, Issue 5, Page(s) e0177001

    Abstract: Vegetated marine habitats are globally important carbon sinks, making a significant contribution towards mitigating climate change, and they provide a wide range of other ecosystem services. However, large gaps in knowledge remain, particularly for ... ...

    Abstract Vegetated marine habitats are globally important carbon sinks, making a significant contribution towards mitigating climate change, and they provide a wide range of other ecosystem services. However, large gaps in knowledge remain, particularly for seagrass meadows in Africa. The present study estimated biomass and sediment organic carbon (Corg) stocks of four dominant seagrass species in Gazi Bay, Kenya. It compared sediment Corg between seagrass areas in vegetated and un-vegetated 'controls', using the naturally patchy occurence of seagrass at this site to test the impacts of seagrass growth on sediment Corg. It also explored relationships between the sediment and above-ground Corg, as well as between the total biomass and above-ground parameters. Sediment Corg was significantly different between species, range: 160.7-233.8 Mg C ha-1 (compared to the global range of 115.3 to 829.2 Mg C ha-1). Vegetated areas in all species had significantly higher sediment Corg compared with un-vegetated controls; the presence of seagrass increased Corg by 4-6 times. Biomass carbon differed significantly between species with means ranging between 4.8-7.1 Mg C ha-1 compared to the global range of 2.5-7.3 Mg C ha-1. To our knowledge, these are among the first results on seagrass sediment Corg to be reported from African seagrass beds; and contribute towards our understanding of the role of seagrass in global carbon dynamics.
    MeSH term(s) Bays ; Biomass ; Carbon/analysis ; Carbon Sequestration ; Climate Change ; Geologic Sediments/analysis ; Grassland ; Kenya
    Chemical Substances Carbon (7440-44-0)
    Language English
    Publishing date 2017-05-10
    Publishing country United States
    Document type Journal Article
    ISSN 1932-6203
    ISSN (online) 1932-6203
    DOI 10.1371/journal.pone.0177001
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Book ; Online: Mixed-methods research in education

    Scoles, Jennifer / Huxham, Mark / McArthur, Jan

    exploring students' response to a focused feedback initiative

    (SAGE research methods. Cases)

    2014  

    Abstract: Researchers who are interested in asking a number of questions about a particular phenomenon are increasingly looking to mixed methods as a useful research approach. In this case study, mixed-methods research is situated in current debates about ... ...

    Author's details Jennifer Scoles & Mark Huxham & Jan McArthur
    Series title SAGE research methods. Cases
    Abstract Researchers who are interested in asking a number of questions about a particular phenomenon are increasingly looking to mixed methods as a useful research approach. In this case study, mixed-methods research is situated in current debates about quantitative and qualitative methods. Then, we provide some reasons as to why researchers see mixed-methods research as an appropriate research method to address problems in complex environments, in particular, in education.
    Keywords Education/Research ; Mixed methods research
    Language English
    Size 1 online resource
    Document type Book ; Online
    ISBN 9781473948617 ; 1473948614
    DOI 10.4135/978144627305013514690
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  7. Article: Climate and intertidal zonation drive variability in the carbon stocks of Sri Lankan mangrove forests

    Liyanaralalage Iroshaka Gregory Marcelus Cooray, Pestheruwe / Arachchilage Sunanda Kodikara, Kodikara / Priyantha Kumara, Marappullige / Indeewari Jayasinghe, Uthpala / Kanishka Madarasinghe, Sanduni / Dahdouh-Guebas, Faird / Gorman, Daniel / Huxham, Mark / Pulukkuttige Jayatissa, Loku

    Elsevier B.V. Geoderma. 2021 May 01, v. 389

    2021  

    Abstract: Sri Lanka is at the forefront of global mangrove conservation. It is the first country to officially protect all its remaining mangrove forests and has embarked on an ambitious plan to restore 10,000 ha of wetland during the United Nations Decade of ... ...

    Abstract Sri Lanka is at the forefront of global mangrove conservation. It is the first country to officially protect all its remaining mangrove forests and has embarked on an ambitious plan to restore 10,000 ha of wetland during the United Nations Decade of Ecosystem Restoration. One incentive for this conservation effort is a recognition, based on research mostly done elsewhere, of the importance of mangroves for carbon sequestration and storage. However, a lack of data on Sri Lankan mangrove carbon pools, especially on soil organic carbon, has been recognized as a major impediment to national climate change mitigation strategies. The current work examined both above and below-ground carbon stocks of five important mangrove forests in Sri Lanka (Rekawa, Puttalam-Kalpitiya, Pambala-Chilaw, Batticaloa and Negombo) which are situated in the three major climate zones (dry, intermediate and wet) and therefore sample the main climatic drivers of spatial variability. Above-ground carbon, below-ground root carbon and soil carbon stocks of mangroves in Sri Lanka ranged from 75.5 to 189.1 Mg C ha⁻¹, 7.9 to 14.3 Mg C ha⁻¹ and 643.6 to 1253.6 Mg C ha⁻¹, respectively. The highest total mangrove carbon stock was recorded from the Rekawa lagoon which is in the intermediate climate zone (1455.4 Mg C ha⁻¹) while the lowest was found in the Batticaloa lagoon in the dry zone (734.7 Mg C ha⁻¹). Soil carbon stocks were substantially higher in the places where vegetation biomass and stand densities are high. Soil comprised 83–90% of the total mangrove carbon stocks at all sites, highlighting the large potential for release into the atmosphere as carbon dioxide if these habitats are disturbed. Overall, our study contributes important data that broadens our current understanding of how mangrove organic carbon pools vary spatially and with climatic zone.
    Keywords biomass ; carbon dioxide ; carbon sequestration ; carbon sinks ; climate change ; climatic zones ; ecological restoration ; littoral zone ; soil ; soil organic carbon ; wetlands ; Sri Lanka
    Language English
    Dates of publication 2021-0501
    Publishing place Elsevier B.V.
    Document type Article
    Note NAL-AP-2-clean
    ZDB-ID 281080-3
    ISSN 1872-6259 ; 0016-7061
    ISSN (online) 1872-6259
    ISSN 0016-7061
    DOI 10.1016/j.geoderma.2021.114929
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  8. Article ; Online: Evaluating, predicting and mapping belowground carbon stores in Kenyan mangroves.

    Gress, Selena K / Huxham, Mark / Kairo, James G / Mugi, Lilian M / Briers, Robert A

    Global change biology

    2017  Volume 23, Issue 1, Page(s) 224–234

    Abstract: Despite covering only approximately 138 000 ... ...

    Abstract Despite covering only approximately 138 000 km
    MeSH term(s) Carbon ; Climate Change ; Conservation of Natural Resources ; Kenya ; Wetlands
    Chemical Substances Carbon (7440-44-0)
    Language English
    Publishing date 2017-01
    Publishing country England
    Document type Journal Article
    ZDB-ID 1281439-8
    ISSN 1365-2486 ; 1354-1013
    ISSN (online) 1365-2486
    ISSN 1354-1013
    DOI 10.1111/gcb.13438
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  9. Article: Exceptionally high mangrove root production rates in the Kelantan Delta, Malaysia; An experimental and comparative study

    Muhammad-Nor, Siti Mariam / Duddy, Symone Jade / Huxham, Mark / Jackson, Gail / Mazars-Simon, Alban / Meir, Patrick / Mencuccini, Maurizio / Salmon, Yann

    Forest ecology and management. 2019 July 15, v. 444

    2019  

    Abstract: Mangroves often allocate a relatively large proportion of their total biomass production to their roots, and the belowground biomass of these forests contributes towards globally significant carbon sinks. However, little information is available on root ... ...

    Abstract Mangroves often allocate a relatively large proportion of their total biomass production to their roots, and the belowground biomass of these forests contributes towards globally significant carbon sinks. However, little information is available on root production in mangroves due to the difficulties in carrying out measurements of belowground processes, particularly if there is regular flooding. In this study, we examined fine and coarse root production in the east coast of the Malaysian Peninsula. Ingrowth cores were used over the course of 17 months. In September 2014, twenty cores were randomly placed in each of five plots. Three cores were collected from each plot (fifteen cores in total), once every three months. Each core was divided into five 10 cm layers and root dry mass was recorded. Standing root biomass was also measured at the time of final collection using an additional 15 cores. There was a seasonal pattern in root production, which peaked in March and December 2015, after and during the monsoon season. Root biomass in the cores peaked at 33.23 ± 6.3 t ha−1 and 21.46 ± 7.3 t ha−1 in March and December respectively. Standing root biomass in February 2016 in the forest was 20.81 ± 2.8 t ha−1. After 17 months, the final root biomass in the cores was 14% less than the standing root biomass. These data suggest surprisingly rapid growth rates and turnover for mangrove roots. Total root biomass significantly increased with root depth and 78% of the roots, in all soil layers, consisted of fine roots (<3 mm diameter). Soil carbon, nitrogen and phosphorous concentrations were investigated in relation to belowground production, as were soil temperature, salinity and dissolved oxygen. A data review of global studies reporting similar work was carried out. The results are discussed with consideration to the significance of monsoon rainfall for mangrove ecology.
    Keywords belowground biomass ; biomass production ; carbon sinks ; coasts ; dissolved oxygen ; ecology ; fine roots ; forests ; monsoon season ; nitrogen ; phosphorus ; rain ; salinity ; seasonal variation ; soil carbon ; soil temperature ; Malaysia
    Language English
    Dates of publication 2019-0715
    Size p. 214-224.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 751138-3
    ISSN 0378-1127
    ISSN 0378-1127
    DOI 10.1016/j.foreco.2019.04.026
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  10. Article ; Online: Multiple impact pathways of the 2015-2016 El Niño in coastal Kenya.

    Fortnam, Matt / Atkins, Molly / Brown, Katrina / Chaigneau, Tomas / Frouws, Ankje / Gwaro, Kemyline / Huxham, Mark / Kairo, James / Kimeli, Amon / Kirui, Bernard / Sheen, Katy

    Ambio

    2020  Volume 50, Issue 1, Page(s) 174–189

    Abstract: The 2015-2016 El Niño had large impacts globally. The effects were not as great as anticipated in Kenya, however, leading some commentators to call it a 'non-event'. Our study uses a novel combination of participatory Climate Vulnerability and Capacity ... ...

    Abstract The 2015-2016 El Niño had large impacts globally. The effects were not as great as anticipated in Kenya, however, leading some commentators to call it a 'non-event'. Our study uses a novel combination of participatory Climate Vulnerability and Capacity Analysis tools, and new and existing social and biophysical data, to analyse vulnerability to, and the multidimensional impacts of, the 2015-2016 El Niño episode in southern coastal Kenya. Using a social-ecological systems lens and a unique dataset, our study reveals impacts overlooked by conventional analysis. We show how El Niño stressors interact with and amplify existing vulnerabilities to differentially impact local ecosystems and people. The policy significance of this finding is that the development of specific national capacities to deal with El Niño events is insufficient; it will be necessary to also address local vulnerabilities to everyday and recurrent stressors and shocks to build resilience to the effects of El Niño and other extremes in climate and weather.
    MeSH term(s) Ecosystem ; El Nino-Southern Oscillation ; Humans ; Kenya ; Weather
    Language English
    Publishing date 2020-03-09
    Publishing country Sweden
    Document type Journal Article
    ZDB-ID 120759-3
    ISSN 1654-7209 ; 0044-7447
    ISSN (online) 1654-7209
    ISSN 0044-7447
    DOI 10.1007/s13280-020-01321-z
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