Biodiversity of benthic fauna in the seagrass ecosystem of Kung Krabaen Bay, Chantaburi Province, Thailand

Biodiversity of benthic fauna was high in the seagrass ecosystem in Kung Krabaen Bay even though the bay’s coasthad many intensive shrimp farms. Halodule pinifolia and Enhalus acoroides were two species of seagrasses distributedwidely in the bay. Their biomass was higher in summer than in the rainy season. 27 families of polychaetes and 10 species ofgastropods were predominantly distributed in the seagrass beds and their biodiversity indices were not different amongtransects (North, East, South). At the same time, 18 species of bivalves were distributed among seagrass beds, but they hada greater diversity index in the north and east than in the south. The abundance of gastropods, bivalves and polychaeteswere significantly correlated with the biomass of H. pinifolia (65%, 39% and 27%, respectively); whereas only bivalvescorrelated significantly with the biomass of E. acoroides (36%). Treated wastewater effluents from shrimp farms did not affectthe seagrass ecosystem. Water quality in the bay was suitable for natural resources preservation

Using the DPSIR framework for transdisciplinary training and knowledge elicitation in the Gulf of Thailand

No abstract available

Too close for comfort: spatial patterns in acorn barnacle populations

Spatial patterns in aggregations form as a result of the interplay between costs and benefits experienced by individuals. Such self-organisation of aggregations can be explained using a zonal model in which a short-range zone of repulsion and longer-range zone of attraction surrounding individuals leads to emergent pattern properties. The signal of these processes can be detected using spatial pattern analyses. Furthermore, in sessile organisms, post-settlement mortality reveals the relative costs and benefits of positions within the aggregation. Acorn barnacles are known to require contact with conspecifics for reproduction and are therefore believed to aggregate for this purpose; isolated individuals may also be more susceptible to abiotic stress and predation. At short distances, however, competition for space and resources is likely to occur. In this study spatial patterns of barnacles (Semibalanus balanoides L.) were analysed using pair-correlation functions. Individuals were dispersed at distances below 0.30 cm, but peak relative density occurred at a distance of 0.36 cm from conspecifics. This is much closer than required for reproductive access, implying a strong aggregative drive, up to the point of physical contact with neighbours. Nevertheless, analysis of dead barnacles illustrated that such proximity carries a cost as barnacles with many neighbours were more likely to have died. The inferences obtained from these patterns are that barnacles aggregate as closely as they can, and that local neighbourhood competition is a powerful determinant of mortality. These processes give rise to the observed pattern properties

Causes of decoupling between larval supply and settlement and consequences for understanding recruitment and population connectivity

Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Experimental Marine Biology and Ecology 392 (2010): 9-21, doi:10.1016/j.jembe.2010.04.008.Marine broadcast spawners have two-phase life cycles, with pelagic larvae and benthic adults. Larval supply and settlement link these two phases and are crucial for the persistence of marine populations. Mainly due to the complexity in sampling larval supply accurately, many researchers use settlement as a proxy for larval supply. Larval supply is a constraining variable for settlement because, without larval supply, there is no settlement. Larval supply and settlement may not be well correlated, however, and settlement may not consistently estimate larval supply. This paper explores the argument that larval supply (i.e., larval abundance near settlement sites) may not relate linearly to settlement. We review the relationship between larval supply and settlement, from estimates and biases in larval supply sampling, to non-behavioral and behavioral components, including small-scale hydrodynamics, competency, gregarious behavior, intensification of settlement, lunar periodicity, predation and cannibalism. Physical and structural processes coupled with behavior, such as small-scale hydrodynamics and intensification of settlement, sometimes result in under- or overestimation of larval supply, where it is predicted from a linear relationship with settlement. Although settlement is a function of larval supply, spatial and temporal processes interact with larval behavior to distort the relationship between larval supply and settlement, and when these distortions act consistently in time and space, they cause biased estimates of larval supply from settlement data. Most of the examples discussed here suggest that behavior is the main source of the decoupling between larval supply and settlement because larval behavior affects the vertical distribution of larvae, the response of larvae to hydrodynamics, intensification of settlement, gregariousness, predation and cannibalism. Thus, larval behavior seems to limit broad generalizations on the regulation of settlement by larval supply. Knowledge of the relationship is further hindered by the lack of a well founded theoretical relationship between the two variables. The larval supply- settlement transition may have strong general consequences for population connectivity, since larval supply is a result of larval transport, and settlement constrains recruitment. Thus, measuring larval supply and settlement effectively allows more accurate quantification and understanding of larval transport, recruitment and population connectivity.JP would like to thank WHOI Ocean Life Institute for partial funding. FP’s contribution is based upon research supported by the South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation

Impact of suspended sediments on the survival of seagrass: Halodule pinifolia (Miki) den Hartog

The research aimed to study the level of suspended sediments on the survival of Halodule pinifolia (Miki) den Hartog. Three experiments were conducted. Broad concentration of suspended sediments covering the level found in nature were employed in the first experiment. The impact concentration of suspended sediments on the survival of H. pinifolia was extended in more detail in the second and third experiments. H. pinifolia was planted by washing off the mud and holding it with a grating. An air pump was used to stir the sediment in suspension during the experiments and necessary water parameters were strictly control. The suspended sediment was spread by siphon and conducted in a period of 30 days for the first and second experiments, and 45 days for the third experiment. The result indicated that suspended sediments with a concentration of 1-64 mg/l had no impact on the survival of H. pinifolia within 30 days. Initially, suspended sediments of 66 mg/l lowered H. pinifolia's survival to 95% at day 30. Concentration of suspended sediments higher than 66 mg/l affected the survival of H. pinifolia. The decreasing survival was noticed during days 20 -25 of the experiment and all died during days 40-45. However, the life span of H. pinifolia, would be very important and might also affect the survival of H. pinifolia after 30 days

Resilience of Small-Scale Fishers to Declining Fisheries in the Gulf of Thailand

Small-scale fishers depend on fishery resources, which have been declining continuously in Thailand and elsewhere; thus, understanding their perceived ability to adapt to future fishery declines is crucial. This study examines factors affecting perceptions of resilience among small-scale fishers in the Gulf of Thailand. Findings indicate that fishers’ responses to the fishery’s decline are associated with four components of resilience including: ability (1) to get work elsewhere; (2) to compete, survive and adapt more effectively; (3) to increase confidence by planning for financial security and learning new skills; and (4) to cope when there is a change. Perceived resilience of fishers to future fishery decline depends on a combination of several factors. Our results indicate that fishers with more education, those from households that do not depend exclusively on fish for income, younger fishers, those who had been fishing for a shorter time, those with higher levels of individual well-being and basic needs components, and those that would not become a fisherman if they had their lives to live over are more likely to be found in the high resilience group. In addition, fishing communities living in an industrial context (developed urban areas) manifest high levels of competitiveness, survivability and adaptability, which are mainly due to the diverse livelihoods provided in such areas in comparison with non-industrial areas. Equitable benefit sharing among fishing association members could be the concern, likely to impact fishers’ perceived resilience. The paper provides recommendations as to how the findings can aid in design of fishery development and governance programs appropriate to the attitudes, beliefs and values of fishers; hence, increasing the likelihood of their relative success

Factors influencing the well-being of small-scale fishers in the Gulf of Thailand

This paper examines factors influencing well-being among small-scale fishers in the Gulf of Thailand. 632 small-scale fishers were interviewed at 21 fish landing areas along the coast of Rayong Province. Data concerning respondents’ background information, perception of job satisfaction, resilience, conservation beliefs, environmental ethics, well-being and landing place context were collected. Multivariate statistical analyses of these variables are used to assess factors influencing perceptions of well-being (environmental and individual well-being components). The results demonstrate that two components of job satisfaction Basic Needs and Self-actualization are two significant variables affecting both Environmental and Individual well-being. Fishers living in areas with industrial pollution or in major urban communities are less satisfied with the environment. Similarly, fishers who are concerned about the importance of the environment and members of a fishery association at the province level have lower levels of Environmental well-being. The study also found that, fishers who feel they have the ability to get work elsewhere or who manifest a higher level of resilience are happier with their lives than those with lower resilience. An important aspect of fisheries social impact assessment concerning proposed changes, management or technological, is the impact on well-being. The findings of this study offer several practical findings that, if applied, will contribute to sustainability of fisheries in Thailand and similar locations

Incorporating fishers’ evaluation of adaptive capacity in policy making in Thailand

Small-scale fishers around the world are facing many challenges in sustaining viable livelihoods due to diverse factors such as declining fisheries resources, degradation of coastal habitats, and climate change impact, among others. How fishers respond to change depends in part on their evaluations of adaptive capacity, and an understanding of factors underlying their evaluations can be helpful in guiding policies and programs to reduce vulnerability and build resilience. The paper presents a study of twelve small-scale fishing communities in eastern Thailand, which illustrates the multiplicity of factors influencing attitudes, beliefs, values and cognitive biases (ABVCs) concerning adaptive capacity. First, the ABVCs of small-scale fishers toward adaptation to changes and the reduction of fishery resources were elicited using a structured survey. Next, principle component analysis was performed on the survey results of 266 respondents, which revealed that the ABVCs concerning adaptive capacity are related to three main components: ability to change occupation (Options component), ability to compete (Ability component), and ability to plan for changes (Plan component). The final step identified factors influencing the adaptive capacity components with the use of regression analysis. Specifically, the ability to change work is positively related to level of education, and negatively associated with age and high dependency on fishing income. Satisfaction with income and with individual well-being determine the ability to compete. The ability to plan for changes, on the other hand, is influenced by evaluated level of closeness to nature, the factor that is expected to be associated with conservation behavior. The findings can aid in designing policies and interventions that align with the adaptive capacity of fishers; hence, enhancing viability and contributing to increasing resilience of small-scale fishing communities

How the DPSIR framework can be used for structuring problems and facilitating empirical research in coastal systems

help organize research that increases understand about interacting ecological and societal processes, predicts change, and supports the management, persistence, and resilience of coastal systems. The Driver–Pressure–State–Impact–Response (DPSIR) framework is one such approach that has been adopted in some coastal zones around the world. Although the application of the DPSIR framework has considerable potential to bridge the gap between scientific disciplines and link science to coastal policy and management, current applications of DPSIR in coastal environments have been limited and new innovations in the application of the DPSIR model are needed. We conducted a structured review of literature on the DPSIR framework as applied to the function, process and components of complex coastal systems. Our specific focus was on how the DPSIR framework has been used as a tool to organize sophisticated empirical scientific research, support transdisciplinary knowledge at a level appropriate for building understanding about coastal systems, and how adopting a DPSIR approach can help stakeholders to articulate and structure challenges in coastal systems and use the framework to support policy and management outcomes. The review revealed that DPSIR models of coastal systems have been largely used to support and develop conceptual understanding of coastal social–ecological systems and to identify drivers and pressures in the coastal realm. A limited number of studies have used DPSIR as a starting point for semi-quantitative or quantitative analyses, although our review highlights the continued need for, and potential of, transformative quantitative analyses and transdisciplinary applications of the DPSIR framework. The DPSIR models we reviewed were predominantly single sector, encompassing ecological or biophysical factors or focusing primarily on socio-cultural dimensions rather than full integration of both types of information. Only in eight of 24 shortlisted articles did researchers actively engage decision-makers or citizens in their research: given the potential opportunity for using DPSIR as a tool to successfully engage policy-makers and stakeholders, it appears that the DPSIR framework has been under-utilized in this regard