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  • 1
    Online Resource
    Online Resource
    Regime shifts in demersal assemblages of the Benguela Current Large Marine Ecosystem: a comparative assessment
    Wiley ; 2015
    In:  Fisheries Oceanography Vol. 24, No. S1 ( 2015-03), p. 15-30
    Details
    In: Fisheries Oceanography, Wiley, Vol. 24, No. S1 ( 2015-03), p. 15-30
    Abstract: Using long‐term survey data, changes in demersal faunal communities in the Benguela Current Large Marine Ecosystem were analysed at community and population levels to provide a comparative overview of the occurrence and timing of regime shifts. For South Africa, the timing of a community‐level shift observed in the early 1990s, and of a lesser shift observed in the mid‐2000s, corresponded well with the results of other studies that showed environmental, community‐level or population‐level changes at similar times, suggesting that environmental forcing had played a role. Several population‐level shifts were detected for Namibia; these and a regime shift in the overall community identified for this country corresponded well to the timing of severe environmental perturbations and an extensive regime shift in the pelagic ecosystem of this area. However, the interpretation of these shifts was confounded by changes in sampling gear; closer scrutiny of the types of species affected and the direction of shifts (increase/decrease) in relation to the timing and nature of sampling gear modifications, revealed that the observed shifts were potentially an artefact of gear changes. This highlighted the importance of accounting for changes in sampling protocols during the analysis and interpretation of long‐term data. For Angola, a community level shift in the mid‐2000s and population‐level changes for a few species (mainly positive), could not have been influenced by gear changes which took place mainly before the onset of the time series under consideration. However, no clear environmental or anthropogenic changes that could have influenced these shifts were obvious.
    Type of Medium: Online Resource
    ISSN: 1054-6006 , 1365-2419
    URL: Issue
    URL: Article
    DOI: 10.1111/fog.2015.24.issue-S1
    DOI: 10.1111/fog.12053
    Language: English
    Publisher: Wiley
    Publication Date: 2015
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    SSG: 21,3
    SSG: 12
    Location Call Number Limitation Availability
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    Online Resource
  • 2
    Online Resource
    Online Resource
    Identifying and characterizing demersal fish biodiversity hotspots in the Benguela Current Large Marine Ecosystem: relevance in the light of global changes
    Oxford University Press (OUP) ; 2013
    In:  ICES Journal of Marine Science Vol. 70, No. 5 ( 2013-09-01), p. 943-954
    Details
    In: ICES Journal of Marine Science, Oxford University Press (OUP), Vol. 70, No. 5 ( 2013-09-01), p. 943-954
    Abstract: Kirkman, S. P., Yemane, D., Kathena, J., Mafwila, S. K., Nsiangango, S. E., Samaai, T., Axelsen, B., and Singh, L. 2013. Identifying and characterizing demersal fish biodiversity hotspots in the Benguela Current Large Marine Ecosystem: relevance in the light of global changes. – ICES Journal of Marine Science, 70: 943–954. This study made use of distribution and abundance data of demersal fish and cephalopod species targeted during trawl surveys off Angola, Namibia and the west coast of South Africa, to determine species richness patterns including the location of diversity hotspots in the Benguela Current Large Marine Ecosystem. The reliability of alternative techniques for determining species richness patterns over the study domain, including geostatistical and non-geostatistical interpolation methods and regression type modelling, was tested using a cross-validation method. Generalized additive models were found to be the most effective method and were used to generate horizontal maps of species richness for different periods in each country. Despite changes in community structure that have been documented during the study period and which may be associated with climatic changes, this study showed the presence of consistently predictable hotspot areas over a 20–30-year study period (depending on country). The relationship between species richness and physical/environmental variables was inconsistent between countries, but generally hotspots of species richness were associated with greater depths and cooler bottom temperatures. Range shifts of species associated, for example, with warming of temperatures could conceivably affect the spatio-temporal persistence of hotspots in the long term.
    Type of Medium: Online Resource
    ISSN: 1095-9289 , 1054-3139
    URL: Article
    DOI: 10.1093/icesjms/fst040
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2013
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    detail.hit.zdb_id: 1468003-8
    detail.hit.zdb_id: 29056-7
    SSG: 12
    SSG: 21,3
    Location Call Number Limitation Availability
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  • 3
    Online Resource
    Online Resource
    Using Systematic Conservation Planning to support Marine Spatial Planning and achieve marine protection targets in the transboundary Benguela Ecosystem
    Elsevier BV ; 2019
    In:  Ocean & Coastal Management Vol. 168 ( 2019-02), p. 117-129
    Details
    In: Ocean & Coastal Management, Elsevier BV, Vol. 168 ( 2019-02), p. 117-129
    Type of Medium: Online Resource
    ISSN: 0964-5691
    URL: Article
    DOI: 10.1016/j.ocecoaman.2018.10.038
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2019
    detail.hit.zdb_id: 1109890-9
    detail.hit.zdb_id: 1497382-0
    SSG: 21,3
    SSG: 14
    Location Call Number Limitation Availability
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  • 4
    Online Resource
    Online Resource
    Spatio‐temporal trends in diversity of demersal fish species in the Benguela current large marine ecosystem region
    Wiley ; 2015
    In:  Fisheries Oceanography Vol. 24, No. S1 ( 2015-03), p. 102-121
    Details
    In: Fisheries Oceanography, Wiley, Vol. 24, No. S1 ( 2015-03), p. 102-121
    Abstract: Biodiversity is changing at an unprecedented rate on a global scale as a complex response to several anthropogenic changes, in addition to the background natural environmental variability and cycles. In the Benguela Current Large Marine Ecosystem region ( BCLME ), aspects of demersal fish species diversity were studied between 1985 and 2010 in three countries (Angola, Namibia, and South Africa) using scientific survey data (depending on country). The study was aimed to address multi‐tiered objectives: to document patterns of diversity (as measured by the different indices of diversity) in the three countries; to relate these patterns to various explanatory variables (depth, latitude, longitude, bottom temperature, and total catch) using a generalized additive model; and to compare the patterns of diversity and importance of potential drivers of biodiversity across the BCLME region. Results showed contrasting diversity patterns between the three countries in terms of both the form and strength of the relationship with different sets of predictors. Species richness S , Pielou's evenness index J' , and Shannon–Wiener index H' were shown to increase with increasing depth in all three countries. In addition, both the overall and depth‐dependent latitudinal pattern in S showed local and regional level bottlenecks in biodiversity, and the latitudinal pattern of S was similar to the pattern of bottom temperature. Overall, the species richness of demersal fish species (S) was found to increase as one moved towards the equator, in line with similar studies that reported an increase in richness with latitude.
    Type of Medium: Online Resource
    ISSN: 1054-6006 , 1365-2419
    URL: Issue
    URL: Article
    DOI: 10.1111/fog.2015.24.issue-S1
    DOI: 10.1111/fog.12075
    Language: English
    Publisher: Wiley
    Publication Date: 2015
    detail.hit.zdb_id: 1214985-8
    detail.hit.zdb_id: 2020300-7
    SSG: 21,3
    SSG: 12
    Location Call Number Limitation Availability
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    Online Resource
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