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Nico Koedam - One of the best experts on this subject based on the ideXlab platform.
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towards an unknown fate the floating behaviour of recently abscised Propagules from wide ranging rhizophoraceae mangrove species
Aquatic Botany, 2017Co-Authors: N Tonne, Elisabeth M. R. Robert, Hans Beeckman, Nico KoedamAbstract:Abstract The persistence of a mangrove ecosystem depends on the potential of its Propagules to disperse. In case of the Rhizophoraceae mangrove species, Propagules are elongated cylinder-shaped seedlings that have an initial ability to float upon abscission from the parent tree. During the hydrochoric dispersal period, propagule traits (e.g. volume and density) change over time, which in parallel influences propagule buoyancy behaviour. Recently abscised, mature Propagules of three rhizophoracean mangrove species (Bruguiera gymnorrhiza (L.) Sav., Ceriops tagal (Perr.) C.B. Rob., Rhizophora mucronata Lam.) were submitted to a three-month floating experiment to investigate the timing and pattern in their buoyancy behaviour linked to changes in propagule density. Anatomical analyses of the aerenchymatous tissues complemented the floatation data. Initial propagule density (between 0.96 (C. tagal) and 0.99 g cm−3 (B. gymnorrhiza and R. mucronata)) was on slightly lower than that of seawater and increased over time in all species but at dissimilar rates. Intra-individual density increased from the plumule- towards the radicle end, and corresponded with a decrease in proportion of intercellular surface area per unit area. The interplay between propagule traits and surface water conditions determine the fate of each propagule and its capacity to escape the local forest and reach open water. The combination of techniques used and hence combination of data obtained in this study, contribute to an increased understanding of mangrove forest dynamics: the potential and the limits therein to expand the species range or to replenish existing populations with new recruits.
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Impact of landscape structure on propagule dispersal in mangrove forests
Marine Ecology Progress Series, 2015Co-Authors: T. Van Der Stocken, Farid Dahdouh-guebas, Dennis De Ryck, Bram Vanschoenwinkel, T.j. Bouma, Evelien Deboelpaep, Nico KoedamAbstract:Although many riparian and semi-aquatic plant species disperse via water currents, little is known about how this process interacts with the landscape matrix. In mangroves, the dense aerial root network could act as a strong dispersal barrier for the morphologically diverse Propagules found in these trees. In this study, we combined field and laboratory experiments to test the effect of root density, propagule morphology and hydrodynamic variables on retention rates and trajectories of the Propagules of 4 common species. Overall, flume experiments showed that larger Propagules were more frequently retained than smaller ones. For the larger Propagules, retention rates increased with increasing obstacle density in the landscape matrix. In elongated Propagules, intraspecific variation was linked to floating orientation. Experimental wave action and increased water flow velocity reduced retention. Dispersal in the field was constrained by major tidal currents and experiments confirmed less retention of smaller Propagules, which moved farther than larger ones. Overall, our results reveal that the pronounced morphological variation in mangrove Propagules interacts with the landscape matrix, contributing to strong differences in dispersal capacity among species and morphotypes. These results may help to explain observed mangrove distribution patterns, including zonation at local, regional and global scales. Additionally, given that many mangrove biotopes are currently strongly threatened by human pressure and fragmentation, this information is important as an input variable for dispersal models that aim to predict dispersal patterns at multiple scales and species responses to environmental change.
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What regulates crab predation on mangrove Propagules
Acta Oecologica, 2015Co-Authors: Fleur Van Nedervelde, Nico Koedam, Stefano Cannicci, Jared O. Bosire, Farid Dahdouh-guebasAbstract:Crabs play a major role in some ecosystems. To increase our knowledge about the factors that influence crab predation on Propagules in mangrove forests, we performed experiments in Gazi Bay, Kenya in July 2009. We tested whether: (1) crab density influences propagule predation rate; (2) crab size influences food competition and predation rate; (3) crabs depredate at different rates according to propagule and canopy cover species; (4) vegetation density is correlated with crab density; (5) food preferences of herbivorous crabs are determined by size, shape and nutritional value. We found that (1) propagule predation rate was positively correlated to crab density. (2) Crab competitive abilities were unrelated to their size. (3) Avicennia marina Propagules were consumed more quickly than Ceriops tagal except under C. tagal canopies. (4) Crab density was negatively correlated with the density of A. marina trees and pneumatophores. (5) Crabs prefer small items with a lower C:N ratio. Vegetation density influences crab density, and crab density affects propagule availability and hence vegetation recruitment rate. Consequently, the mutual relationships between vegetation and crab populations could be important for forest restoration success and management.
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PRELIMINARY STUDY ON THE PROPAGULE DEPENDENCY OF Rhizophora SEEDLINGS
2014Co-Authors: N. P. Dissanayake, Nico Koedam, Loku Pulukkuttige Jayatissa, S.k. Madarasinghe, Kodikara Arachchilage Sunanda Kodikara, A.j.d. Perera, F. Dahdouh GuebasAbstract:Early life of viviparous mangroves merely depends on the propagule and it can be assumed that the period and the degree of dependency could depend on the size and the intrinsic factors of the propagule as well as on the edaphic and environmental factors in which the seedlings are growing. However scientific studies on the propagule dependency of mangrove seedlings is poorly studied, irrespective to the fact that such information is vital particularly in mangrove restoration programs. However, propagule dependency of mangrove seedlings is poorly studied scientifically, irrespective to the fact that such information is vital particularly in mangrove restoration programs. This study was carried out to investigate the growth performances of seedlings and the variations in the content of carbohydrate foods (starch content) in the propagule during the first 20 weeks period of the seedling growth of two viviparous species, Rhizophora apiculata and Rhizophora mucronata , which are having larger Propagules and commonly used in replanting programs. The experiment was conducted, under three salinity regimes (i.e. 5psu; 15psu; 30psu) in a planthouse. A separate set of Propagules was planted within the mangrove forest of Pambala lagoon under natural conditions and subjected to the same investigation as above. Growth performances of both species grown under high salinity regime were significantly lower than those grown in low and moderate salinity regimes. Total leaf area of the seedlings of R. mucronata increased in higher order compared to that of the R. apiculata during the study period. After an initial drop in the content of starch in the Propagules of both species, it started to increase slowly in the propagule of R. mucronata seedlings whilst the reduction was continued in R. apiculata Propagules during the study period. However, the initial starch concentration of R. apiculata was remarkably higher than that of R. mucronata and hence, the starch content in R. apiculata, even after continued decreasing, was higher at the end of the study period. It can be hypothesized that the higher concentration of the stored food in smaller propagule of R. apiculate, compared to lower concentration of the stored food in Propagules of R. mucronata, might lead to a similar longevity of viviparous mangrove seedlings of the two species allowing more or less the same chance to survive and establish in the same habitat as observed in many mangrove ecosystems. KEYWORDS: Mangroves, Restoration, Starch content, Propagule dependency, Rhizophora , Sri Lanka
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Modelling drivers of mangrove propagule dispersal and restoration of abandoned shrimp farms
Biogeosciences, 2013Co-Authors: Diana Di Nitto, Paul L. A. Erftemeijer, J.k.l. Van Beek, Farid Dahdouh-guebas, L. Higazi, Katrien Quisthoudt, Loku Pulukkuttige Jayatissa, Nico KoedamAbstract:Propagule dispersal of four mangrove species Rhizophora mucronata, R. apiculata, Ceriops tagal and Avicennia officinalis in the Pambala–Chilaw Lagoon Complex (Sri Lanka) was studied by combining a hydrodynamic model with species-specific knowledge on propagule dispersal behaviour. Propagule transport was simulated using a finite-volume advection-diffusion model to investigate the effect of dispersal vectors (tidal flow, freshwater discharge and wind), trapping agents (retention by vegetation) and seed characteristics (buoyancy) on propagule dispersal patterns. Sensitivity analysis showed that smaller Propagules, like the oval-shaped Propagules of Avicennia officinalis , dispersed over larger distances and were most sensitive to changing values of retention by mangrove vegetation compared to larger, torpedo-shaped Propagules of Rhizophora spp. and C. tagal . Directional propagule dispersal in this semi-enclosed lagoon with a small tidal range was strongly concentrated towards the edges of the lagoon and channels. Short distance dispersal appeared to be the main dispersal strategy for all four studied species, with most of the Propagules being retained within the vegetation. Only a small proportion (max. 5%) of Propagules left the lagoon through a channel connecting the lagoon with the open sea. Wind significantly influenced dispersal distance and direction once Propagules entered the lagoon or adjacent channels. Implications of these findings for mangrove restoration were tested by simulating partial removal in the model of dikes around abandoned shrimp ponds to restore tidal hydrology and facilitate natural recolonisation by mangroves. The specific location of dike removal, (with respect to the vicinity of mangroves and independently suitable hydrodynamic flows), was found to significantly affect the resultant quantities and species of inflowing Propagules and hence the potential effectiveness of natural regeneration. These results demonstrate the value of propagule dispersal modelling in guiding hydrological restoration efforts that aim to facilitate natural mangrove regeneration.
Xuelei Zhang - One of the best experts on this subject based on the ideXlab platform.
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temporal and spatial distributions of green algae micro Propagules in the coastal waters of the subei shoal china
Estuarine Coastal and Shelf Science, 2015Co-Authors: Wei Song, Song Fang, Zongling Wang, Jie Xiao, Mingyuan Zhu, Xuelei ZhangAbstract:Abstract The blooms of large-scale green tides in the Yellow Sea have become a focus of marine research in China. Micro-Propagules, as the propagule source of green algae, played an important role in the formation of green tides. In this study, monthly surveys in the coastal area of the Subei Shoal were conducted from October 2010 to October 2011. The temporal and spatial distributions of green algae micro-Propagules in the water column and sediment were investigated. Green algae micro-Propagules were widely distributed in the waters and sediments throughout the year, and their distribution significantly corresponded to Porphyra aquaculture activities. The abundance of the micro-Propagules decreased gradually from inshore to offshore. The average number of micro-Propagules reached a maximum in late April and was low during the winter and summer. The source of the micro-Propagules was the green algae attached to the Porphyra aquaculture rafts. The green algae micro-Propagules might serve as the seed stock of the raft-attached green algae and provide the initial conditions for the formation of green tides.
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tempo spatial distribution and species diversity of green algae micro Propagules in the yellow sea during the large scale green tide development
Harmful Algae, 2014Co-Authors: Wei Song, Zongling Wang, Jie Xiao, Mingyuan Zhu, Xuelei Zhang, Xiaona WangAbstract:Abstract From 2008 to 2013, vast green tides mainly composed of Ulva prolifera consecutively invaded the coast of Qingdao (36°06′N, 120°25′E, PR China) in June and July. Previous studies have shown that the early green tides initially formed in the Porphyra yezoensis aquaculture area of the Subei Shoal, southern Yellow Sea. To date, multiple studies have demonstrated that green algae micro-Propagules play an important role in the formation of green tides. In this study, we aimed to assess the temporal and spatial distribution of green algae micro-Propagules in an extensive area of the Yellow Sea and to determine the species diversity of Propagules during the development of the large-scale green tide. We found that the quantity of micro-Propagules increased with the free-floating biomass from the initial generation to the development phase of the green tide in mid May. From late May to mid June, the micro-propagule density decreased sharply despite a continuous increase of the floating macroalgae biomass. In addition, our data indicate that the coastal area of the Subei Shoal has always been the distribution center of the micro-Propagules, even prior to the large-scale green tide formation. Furthermore, diverse green algae species, including Ulva prolifera, Ulva linza, Ulva flexuosa, Ulva compressa, Ulva pertusa and Blidingia sp., were identified among the micro-Propagules in the survey sea area. Finally, we determined that the distribution of U. prolifera micro-Propagules is closely related to the floating algal mats and attached macroalgae on Porphyra aquaculture rafts.
Wei Song - One of the best experts on this subject based on the ideXlab platform.
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temporal and spatial distributions of green algae micro Propagules in the coastal waters of the subei shoal china
Estuarine Coastal and Shelf Science, 2015Co-Authors: Wei Song, Song Fang, Zongling Wang, Jie Xiao, Mingyuan Zhu, Xuelei ZhangAbstract:Abstract The blooms of large-scale green tides in the Yellow Sea have become a focus of marine research in China. Micro-Propagules, as the propagule source of green algae, played an important role in the formation of green tides. In this study, monthly surveys in the coastal area of the Subei Shoal were conducted from October 2010 to October 2011. The temporal and spatial distributions of green algae micro-Propagules in the water column and sediment were investigated. Green algae micro-Propagules were widely distributed in the waters and sediments throughout the year, and their distribution significantly corresponded to Porphyra aquaculture activities. The abundance of the micro-Propagules decreased gradually from inshore to offshore. The average number of micro-Propagules reached a maximum in late April and was low during the winter and summer. The source of the micro-Propagules was the green algae attached to the Porphyra aquaculture rafts. The green algae micro-Propagules might serve as the seed stock of the raft-attached green algae and provide the initial conditions for the formation of green tides.
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tempo spatial distribution and species diversity of green algae micro Propagules in the yellow sea during the large scale green tide development
Harmful Algae, 2014Co-Authors: Wei Song, Zongling Wang, Jie Xiao, Mingyuan Zhu, Xuelei Zhang, Xiaona WangAbstract:Abstract From 2008 to 2013, vast green tides mainly composed of Ulva prolifera consecutively invaded the coast of Qingdao (36°06′N, 120°25′E, PR China) in June and July. Previous studies have shown that the early green tides initially formed in the Porphyra yezoensis aquaculture area of the Subei Shoal, southern Yellow Sea. To date, multiple studies have demonstrated that green algae micro-Propagules play an important role in the formation of green tides. In this study, we aimed to assess the temporal and spatial distribution of green algae micro-Propagules in an extensive area of the Yellow Sea and to determine the species diversity of Propagules during the development of the large-scale green tide. We found that the quantity of micro-Propagules increased with the free-floating biomass from the initial generation to the development phase of the green tide in mid May. From late May to mid June, the micro-propagule density decreased sharply despite a continuous increase of the floating macroalgae biomass. In addition, our data indicate that the coastal area of the Subei Shoal has always been the distribution center of the micro-Propagules, even prior to the large-scale green tide formation. Furthermore, diverse green algae species, including Ulva prolifera, Ulva linza, Ulva flexuosa, Ulva compressa, Ulva pertusa and Blidingia sp., were identified among the micro-Propagules in the survey sea area. Finally, we determined that the distribution of U. prolifera micro-Propagules is closely related to the floating algal mats and attached macroalgae on Porphyra aquaculture rafts.
Mark W. Hester - One of the best experts on this subject based on the ideXlab platform.
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Limited Mangrove Propagule Retention at a Latitudinal Range Limit: Spatiotemporal Patterns at the Patch Scale
Estuaries and Coasts, 2020Co-Authors: Erik S. Yando, Scott F. Jones, Mark W. HesterAbstract:Dispersal and establishment dynamics are critical in understanding shifts in species’ ranges. We seek to illuminate patch-level dispersal dynamics by examining the shifting salt marsh-mangrove ecotone. Specifically, we ask the following: (1) How are mangrove Propagules dispersed, retained, and exported within a discrete patch? (2) How do differences across a flooding gradient influence propagule dispersal dynamics? (3) How does the distribution of established seedlings compare to propagule movements? Avicennia germinans is the most temperate mangrove species in the northern Gulf of Mexico forming an ecotone with Spartina alterniflora marshes in coastal Louisiana. Sets of 500 distinctively marked mangrove Propagules were placed at five different elevations. After their release, we observed dispersal dynamics for 1 month. Retention was limited in the study area (
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Reproductive Ecology of Black Mangrove (Avicennia germinans) Along the Louisiana Coast: Propagule Production Cycles, Dispersal Limitations, and Establishment Elevations
Estuaries and Coasts, 2011Co-Authors: Lauren K. Alleman, Mark W. HesterAbstract:Black mangrove ( Avicennia germinans ) reproduces by producing Propagules through the process of cryptovivipary, which requires a significant energy investment. We conducted a series of field and greenhouse studies to track propagule production in years of high and low disturbances (i.e., hurricanes), the effects of time and salinity on propagule dispersal potential, and the relationship between hydrology and propagule establishment elevations. Trees tended to produce greater numbers of Propagules in years after hurricanes, and individual trees alternated the amount of energy they invested in reproduction in consecutive years. In the greenhouse, propagule buoyancy was affected by salinity with Propagules in 36 remaining buoyant for over 110 days and establishment success decreasing with dispersal period length. Finally, a field survey across five sites in southeastern Louisiana revealed that the 2009 cohort of Propagules established at significantly lower elevations than mature trees occurred. These findings elucidate some salient features of black mangrove reproductive biology in the northern portion of its North American distribution.
Mingyuan Zhu - One of the best experts on this subject based on the ideXlab platform.
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temporal and spatial distributions of green algae micro Propagules in the coastal waters of the subei shoal china
Estuarine Coastal and Shelf Science, 2015Co-Authors: Wei Song, Song Fang, Zongling Wang, Jie Xiao, Mingyuan Zhu, Xuelei ZhangAbstract:Abstract The blooms of large-scale green tides in the Yellow Sea have become a focus of marine research in China. Micro-Propagules, as the propagule source of green algae, played an important role in the formation of green tides. In this study, monthly surveys in the coastal area of the Subei Shoal were conducted from October 2010 to October 2011. The temporal and spatial distributions of green algae micro-Propagules in the water column and sediment were investigated. Green algae micro-Propagules were widely distributed in the waters and sediments throughout the year, and their distribution significantly corresponded to Porphyra aquaculture activities. The abundance of the micro-Propagules decreased gradually from inshore to offshore. The average number of micro-Propagules reached a maximum in late April and was low during the winter and summer. The source of the micro-Propagules was the green algae attached to the Porphyra aquaculture rafts. The green algae micro-Propagules might serve as the seed stock of the raft-attached green algae and provide the initial conditions for the formation of green tides.
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tempo spatial distribution and species diversity of green algae micro Propagules in the yellow sea during the large scale green tide development
Harmful Algae, 2014Co-Authors: Wei Song, Zongling Wang, Jie Xiao, Mingyuan Zhu, Xuelei Zhang, Xiaona WangAbstract:Abstract From 2008 to 2013, vast green tides mainly composed of Ulva prolifera consecutively invaded the coast of Qingdao (36°06′N, 120°25′E, PR China) in June and July. Previous studies have shown that the early green tides initially formed in the Porphyra yezoensis aquaculture area of the Subei Shoal, southern Yellow Sea. To date, multiple studies have demonstrated that green algae micro-Propagules play an important role in the formation of green tides. In this study, we aimed to assess the temporal and spatial distribution of green algae micro-Propagules in an extensive area of the Yellow Sea and to determine the species diversity of Propagules during the development of the large-scale green tide. We found that the quantity of micro-Propagules increased with the free-floating biomass from the initial generation to the development phase of the green tide in mid May. From late May to mid June, the micro-propagule density decreased sharply despite a continuous increase of the floating macroalgae biomass. In addition, our data indicate that the coastal area of the Subei Shoal has always been the distribution center of the micro-Propagules, even prior to the large-scale green tide formation. Furthermore, diverse green algae species, including Ulva prolifera, Ulva linza, Ulva flexuosa, Ulva compressa, Ulva pertusa and Blidingia sp., were identified among the micro-Propagules in the survey sea area. Finally, we determined that the distribution of U. prolifera micro-Propagules is closely related to the floating algal mats and attached macroalgae on Porphyra aquaculture rafts.
