Propagule predators in Kenyan mangroves and their possible effect on regeneration

Dahdouh‐Guebas, Farid; Verneirt, Marc; Tack, Jurgen; Speybroeck, D. Van; Koedam, Nico

doi:10.1071/mf97108

Cited by 84 publications

(34 citation statements)

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“…We are only aware of one other published account of extensive damage of X. granatum seeds by crabs (Dahdouh-Guebas et al 1998), though such damage has also reportedly occurred to seeds sown on at least one other Micronesian island (Island of Pohnpei; H. Anson, personal communication). Although we did not directly observe crabs feeding on our X. granatum seeds, the pattern of damage we attributed to crabs, which generally included the removal of a substantial portion of the seed coat and seed contents and also included a total of 13.7% that were taken belowground, differed markedly from the obvious boreholes, tunnels, and frass associated with most insect damage.…”

Section: Effects Of Seed Predationmentioning

confidence: 93%

Factors limiting the intertidal distribution of the mangrove species Xylocarpus granatum

2003

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The tree species Xylocarpus granatum is commonly described as occurring in the upper intertidal zone of mangrove forests, but mature trees are occasionally found at lower elevations. In the Utwe River basin, on the Pacific island of Kosrae, we investigated the relative importance of several biotic and abiotic factors that may control the intertidal distribution of X. granatum. Factors we evaluated included differential seed predation across the lower, mid, and upper intertidal zones and seedling responses to salinity, tidal flooding, and shade. Seed predation was 22.4% over the first 34 days and varied little among zones or in gaps versus under the forest canopy. By day 161, there were still no differences in seed mortality, but a significant difference was found in seedling establishment, with much greater establishment in the upper intertidal plots. X. granatum seedlings in a greenhouse experiment exhibited greater growth in freshwater than seedlings in 23 ppt salinity, which is typical of salinity levels found in the mid intertidal zone in our field study sites in Micronesia, where mature X. granatum trees are generally absent. Seedlings grown in 23 ppt salinity, however, exhibited few visible signs of stress associated with patterns in growth. Seedlings grown in a simulated tidal flooding treatment (with 23 ppt salinity) also showed few signs of stress. Growth declined dramatically under 80% shade cloths, but there were few interactions of shading with either 23 ppt salinity or simulated tidal flooding. Differential seed predation is not likely to be the primary factor responsible for the intertidal distribution of X. granatum on Kosrae. However, seedling tolerance of flooding or salinity may be more important, especially relative to a potential contribution to secondary stress mortality. Other factors may ultimately prove to be more critical, such as physiological effects of salinity on seed germination, effects of tides on seed dispersal and rooting, or differential herbivory on seedlings.

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Section: Effects Of Seed Predationmentioning

confidence: 93%

Factors limiting the intertidal distribution of the mangrove species Xylocarpus granatum

2003

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“…Predation may be higher in lower intertidal areas or may be similar among positions (Osborne & Smith, 1990;Sousa & Mitchell, 1999;. In some cases, crab predation is unrelated to whether it occurs in small canopy gaps or under a forest canopy, but in other cases predation is higher in understory (Dahdouh-Guebas et al, 1998;Sousa & Mitchell, 1999;Allen et al, 2003;. Predation may be higher in pruned reforestation stands than in unpruned stands (Bosire et al, 2005).…”

Section: Introductionmentioning

confidence: 93%

Predation on propagules and seedlings in mature and regenerating mangroves in the coast of Ceará, Brazil

Souza

Sampaio

2010

Hydrobiologia

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Litterfall consumption and predation on propagules is high in Indo-west-Pacific mangroves and low in Atlantic-east-Pacific ones. However, data for the latter area comes only from Caribbean and subtropical North American mangroves. South American data on litterfall consumption contradicts this view but data on predation on propagules are scarce. We measured predation on Rhizophora mangle, Avicennia schaueriana and Laguncularia racemosa propagules and seedlings and related to densities of large ([1.5 m high) and small (1-1.5 m) plants in mature and regenerating mangroves in Ceará state, Brazil. Predation on propagules was the highest among American mangroves (R. mange,[47%; A. schaueriana, [97%; L. racemosa, [83%), especially in the regenerating area. Predation on seedlings was low (maximum of 14% for R. mangle) and did not hamper growth. The dominance of large R. mangle trees in the mature mangrove is consistent with the lower predation on its propagules but the high proportions of small plants of other species indicate that dominance is achieved by mechanisms other than predation. In the regenerating mangrove, dominance of large and small L. racemosa and A. schaueriana plants is not consistent with the high predation on their propagules. Therefore, predation is not the main determinant of the species composition in this mangrove system.

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“…Although sesarmid crab is considered a propagule predator and has a potential negative effect on mangrove regeneration (Dahdouh-Guebas et al, 1998), the respondents rated this effect to be very low (0.9). The respondents might consider the benefits of sesarmid crabs as a fishery resource provided by the mangrove ecosystem rather than the negative effects on mangrove areas.…”

Section: Perceptions Of Threats To Mangrovesmentioning

confidence: 99%

Factors Affecting Fishers' Perceptions of Benefits, Threats, and State, and Participation in Mangrove Management in Pak Phanang Bay, Thailand

Jumnongsong

Gallardo

Ikejima

et al. 2015

Journal of Coastal Research

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Jumnongsong, S.; Gallardo, W.G.; Ikejima, K., and Cochard, R., 2015. Factors affecting fishers' perceptions of benefits, threats, and state, and participation in mangrove management in Pak Phanang Bay, Thailand. Journal of Coastal Research, 31(1), 95-106. Coconut Creek (Florida), ISSN 0749-0208.Mangrove ecosystems provide a variety of services to people living on the coasts, in particular fishers whose livelihoods depend on healthy stocks of fish and other marine products. Fishers' participation and their understanding about mangroves are vital in mangrove management. This research was conducted to identify the factors contributing to the fishers' perceptions of the mangrove resources and their participation in mangrove management. In this study, mangroves in Pak Phanang Bay in Thailand were assessed in terms of state (diversity, structure, and regeneration) using the point-centered quarter method and fishers' perceptions of mangrove benefits, threats, and state, and their participation in management was investigated using a questionnaire. Ordinal logistic regression revealed that fishers' perceptions of mangrove benefits, threats, and state differed by residence location. Mangrove-related training affected perceptions of benefit and state, and participation in mangrove management, whereas local group membership affected perceptions of threat. Monthly income was identified as an important factor for participation. The perception of benefit is more important for participation in mangrove management compared with the perception of threat and mangrove state. There were some inconsistencies between the perceptions of mangrove state and the field study results; thus, it is recommended that a program that adopts a participatory approach including mangrove monitoring by the villagers could improve perceptions and understanding of mangrove state. Information on the actual state of mangroves and knowledge, particularly on mangrove ecosystem services, should be disseminated to the community via mangrove-related training and local group activities to enhance participation in mangrove management. ADDITIONAL INDEX WORDS:Coastal fishers, fishing community, mangrove ecosystem services, ordinal logistic regression, point-centered quarter method.

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Propagule predators in Kenyan mangroves and their possible effect on regeneration

Cited by 84 publications

References 0 publications

Factors limiting the intertidal distribution of the mangrove species Xylocarpus granatum

Factors limiting the intertidal distribution of the mangrove species Xylocarpus granatum

Predation on propagules and seedlings in mature and regenerating mangroves in the coast of Ceará, Brazil

Factors Affecting Fishers' Perceptions of Benefits, Threats, and State, and Participation in Mangrove Management in Pak Phanang Bay, Thailand

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