Temporal patterns in species zonation in a mangrove forest in the Mekong Delta, Vietnam, using a time series of Landsat imagery

Bullock, Eric L.; Fagherazzi, Sergio; Nardin, William; Vo-Luong, Phuoc; Nguyen, Phong Thanh; Woodcock, Curtis E.

doi:10.1016/j.csr.2017.07.007

Cited by 45 publications

(37 citation statements)

References 40 publications

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“…The island is located at the terminus of the Sông Hậu distributary channel of the river where it discharges into the East Sea (South China Sea). The southeastern, seaward edge of the island is covered by a mangrove forest that grades from dominantly Sonneratia caseolaris mangroves at the shoreward edge to a mixture of Sonneratia spp., Avicennia spp., and Aegiceras corniculatum mangroves and Nypa fruticans palms in the forest interior (Bullock et al, ). Seaward of the mangrove forest, a shallow interlaminated mud and sand flat extends for several kilometers (Fricke et al, ).…”

Section: Field Experiments and Methodsmentioning

confidence: 99%

Turbulence Within Natural Mangrove Pneumatophore Canopies

et al. 2019

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High‐resolution velocity measurements were collected within and above two dense canopies of mangrove pneumatophore roots in a wave‐exposed mangrove forest. In both canopies, root density decreased steadily with height above bed owing to the variability in root heights and the tapered shape of the roots. Within the canopies, we consider turbulence within three zones: near the bed above the wave boundary layer, around the mean canopy height, and above the canopy. The near‐bed turbulence was particularly intense (up to 6.5 × 10−4 W/kg), likely owing to oscillatory wave‐driven currents flowing past dense vegetation. Near the bed and around the mean canopy height, peaks in horizontal velocity power spectra at frequencies corresponding to Strouhal numbers of ~0.2 may indicate Von Kármán wake shedding in the lee of the pneumatophores. Furthermore, a recirculation zone was observed immediately behind a cluster of pneumatophores at intermediate heights. These coherent flow structures were associated with zones of enhanced Reynolds stresses (up to 5.3 × 10−3 m2/s2) and eddy viscosities (up to 1.9 × 10−3 m2/s). Large near‐bed stresses were associated with near‐bed drag coefficients that are up to an order of magnitude larger than those expected in the absence of vegetation. Observed eddy viscosities are consistent with theoretical expectations, derived from scaling arguments using a standard mixing‐length model. These results suggest that pneumatophore roots can contribute greatly to turbulent mixing (e.g., eddy viscosities were on average O(10−4–10−3 m2/s) and therefore may enhance the sediment transport occurring in mangrove forest fringes.

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Section: Field Experiments and Methodsmentioning

confidence: 99%

Turbulence Within Natural Mangrove Pneumatophore Canopies

et al. 2019

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“…Moreover, the core zone is located on the boundary between Mainland China and Hong Kong, for which access to the core zone requires permission from the Immigration Department of the Hong Kong government. Mangroves require a disturbance-free period to establish roots in order to protect themselves from waves and strong currents [10,28]. Since the whole Mai Po reserve was under good protection, mangroves in Mai Po grew without much influence from human activity during the study period, which is an important anthropogenic factor effecting the expansion of mangroves in the recent 25 years.…”

Section: Discussion On the Driving Factors Of Mangrove Changesmentioning

confidence: 99%

“…It is important to understand the zonation of mangrove species (ZMS), which often contributes to the responses of individual species to variations in the degree of abiotic and biotic factors [7][8][9][10]. With the increasing spatial and temporal resolution of satellite technologies, changes of mangrove stands can be monitored at species level, and at a large scale [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Zonation and Directional Dynamics of Mangrove Forests Derived from Time-Series Satellite Imagery in Mai Po, Hong Kong

et al. 2018

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Mangrove deforestation is occurring globally at a rapid rate, and is causing serious ecological and economic losses on all scales. Monitoring mangrove changes is the first important step for mangrove management and conservation. Zonation of mangrove species (ZMS) is the predictable and discrete ordering of mangrove species caused by a unique, intertidal environment. Mapping the ZMS is critical to understanding the mangrove community at a species level. In this paper, the Standard Deviational Ellipse (SDE) was proposed as a method to evaluate mangrove species from a new dimension of directional changes. Three dominant mangrove species, Kandelia obovata (KO), Avicennia marina (AM), and Acanthus ilicifolius (AI), in Mai Po, Hong Kong were analyzed using SDEs based on the time series Système Pour l'Observation de la Terre (SPOT) and Gaofen-1 (GF-1) satellite images. The SDE results demonstrated that in the past 25 years: (1) The overall spatial extent of the mangroves in Mai Po expanded significantly, approximately from 150 to 350 Ha, and show a zonation pattern with a clear sequence of species perpendicular to the shoreline; (2) KO was the dominant species in most years, showing the strongest directional characteristic; (3) All three species zones have moved toward the north and west, as observed by the SDE centers. The SDE was proved to be a useful tool for understanding the temporal and spatial changes of mangrove zonation.

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“…Abiotic and biotic conditions are being affected by climate change, and both can change plant-plant interactions (Pyšek and Richardson 2010). Intertidal plants commonly occur in elevational "zones" because different species perform best at different intertidal elevations (Tomlinson 1986;Pennings and Callaway 1992;Michener et al 1997;Krauss et al 2008;Nardin et al 2016;Bullock et al 2017;Fagherazzi et al 2017). If the interaction between S. alterniflora and S. apetala varies across elevation, it is possible that one species will dominate one part of the intertidal and the other species will dominate other elevations.…”

mentioning

confidence: 99%

“…There are a number of methods available to study the distribution and interactions of multiple plant species within the intertidal zone, including observational studies, field transplant experiments, and "marsh organ" experiments (Morris 2007;Kirwan and Guntenspergen 2012;Zhang et al 2012;Voss et al 2013;Nardin et al 2016;Bullock et al 2017). Each has its own strengths and weaknesses.…”

mentioning

confidence: 99%

Using a marsh organ to predict future plant communities in a Chinese estuary invaded by an exotic grass and mangrove

Peng

Chen

Pennings

et al. 2018

Limnology & Oceanography

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Exotic species vary in how harmful they are. The earlier we can predict the outcome of an invasion, the more time is available for management. We conducted a “marsh organ” experiment with six elevation treatments to evaluate how the exotic grass Spartina alterniflora, which has invaded almost the entire coastline of China, affects a native (Kandelia obovata) and an exotic (Sonneratia apetala) mangrove in Zhangjiang Estuary, southern China. Survival of transplants in monoculture over two growing seasons in the marsh organ was high except at extreme high and low elevations. All three plants displayed hump‐shaped patterns of biomass across elevation in monoculture, but K. obovata performed best at slightly higher and S. alterniflora at slightly lower elevations, whereas S. apetala performed well across all four intermediate elevations and grew larger than the other two plants. In mixtures, S. alterniflora suppressed growth of mangrove seedlings of both species by up to 90%. The competitive effect of S. alterniflora was greatest at intermediate elevations where its biomass was greatest. When transplanted into adjacent stands of S. alterniflora, K. obovata remained stunted, but S. apetala grew quickly and began to emerge from the canopy of S. alterniflora by the end of the second growing season. At this site, past and ongoing disturbances to mature stands of K. obovata are likely to allow both exotics to increase in abundance. Aggressive management intervention will be needed to prevent estuaries in southern China from transitioning to near complete dominance by the exotic mangrove S. apetala.

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Temporal patterns in species zonation in a mangrove forest in the Mekong Delta, Vietnam, using a time series of Landsat imagery

Cited by 45 publications

References 40 publications

Turbulence Within Natural Mangrove Pneumatophore Canopies

Turbulence Within Natural Mangrove Pneumatophore Canopies

Zonation and Directional Dynamics of Mangrove Forests Derived from Time-Series Satellite Imagery in Mai Po, Hong Kong

Using a marsh organ to predict future plant communities in a Chinese estuary invaded by an exotic grass and mangrove

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