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1.
The Coastal Resources Institute (CORIN) at Prince of Songkla University worked with local communities to understand coastal issues and opportunities of the Pak Phanang Bay in Nakhon Si Thammarat, Southern Thailand. Historically, the area has been an important agricultural field and trading town but now it is characterized by slow population growth due to out migration and a decreased economic base. Residents have noted major environmental degradation within their lifetimes. Through the Ecological History, which means a history of the way people and nature have interacted over time, an initial identification and assessment of the key environmental problems were made with the participation and support of the people of Pak Phanang. The approach is based on the belief that for successful resources management, it needs action by local people, supported by the government, that will safeguard and restore local ecosystems.  相似文献   

2.
A total of 98 Manihot species have been recognized in the genus. All of them are native to the tropics of the New World, particularly Brazil and Mexico. The cultigen, Manihot esculenta Crantz (cassava), grows throughout the lowland tropics. Wild species vary in growth habit from acaulescent or short shrubs to tree-like. Because of their adaptations to different conditions, they are gene reservoirs for tackling many abiotic and biotic stresses such as improving root quality and resistance to diseases. They have been used successfully by the first author for improving protein content, seed-fertility, apomixis, resistance to mealy bug, and tolerance to drought. A table of the most important species from an economic viewpoint is presented.  相似文献   

3.
The p21-activated kinases are effector proteins for Rho-family GTPases. PAK4, PAK5, and PAK6 are the group II PAKs associated with neurite outgrowth, filopodia formation, and cell survival. Pak4 knockout mice are embryonic lethal, while Pak5, Pak6, and Pak5/Pak6 double knockout mice are viable and fertile. Our previous work found that the double knockout mice exhibit locomotor changes and learning and memory deficits. We also found some differences with Pak5 and Pak6 single knockout mice and the present work further explores the potential differences of the Pak5 knockout and Pak6 knockout mice in comparison with wild type mice. The Pak6 knockout mice were found to weigh significantly more than the other genotypes. The double knockout mice were found to be less active than the other genotypes. The Pak5 knockout mice and the double knockout mice performed worse on the rotorod test. All the knockout genotypes were found to be less aggressive in the resident intruder paradigm. The double knockout mice were, once again, found to perform worse in the active avoidance assay. These results indicate, that although some behavioral differences are seen in the Pak5 and Pak6 single knockout mice, the double knockout mice exhibit the greatest changes in locomotion and learning and memory.  相似文献   

4.
Life-history traits of commercially important species, physiological attributes of the framework species, and characteristics of ecosystem processes make coral reefs especially vulnerable to export of biomass. Organisms in ecosystems driven by upwelling and terrestrial nutrient input are more amenable to biomass yield. Nonexportive approaches to resource management, exemplified by Palau, are compatible with the attributes of coral-reef ecosystems; they satisfy to a greater degree the economic demands and pressures of growing human populations, and they provide motivation to manage.  相似文献   

5.
Bycatch remains one of the most significant fisheries issues in the world and its monitoring and reporting is now expected in many regions. This paper provides a global synthesis of the data that are available on one of the most controversial components of bycatch, that associated with the capture and discarding of endangered, threatened and protected (ETP) species in marine commercial and artisanal fisheries. We examine the available literature regarding estimates for the key taxa in this category of bycatch (seabirds, turtles, sea snakes, marine mammals, sharks, rays and teleosts) and use the data to try to provide a total global estimate. We estimate (albeit quite imprecisely) that at least 20 million individuals of such species are discarded annually throughout the world. However, there remain far too many gaps and uncertainties across fisheries and regions in the information to provide any robustness (or variance) around such an estimate, nor to determine the actual fates of these animals (many may survive). This is exacerbated because: (1) the occurrences of such species are often rare and controversial and so go either unnoticed and/or unrecorded; (2) different levels of protection are afforded to different ETP species in different countries and fisheries and; (3) discarding practices vary greatly across a hierarchy of spatio-temporal scales and according to individual fishing conditions and procedures—the latter affecting actual mortalities. Nevertheless, there have been major initiatives established in recent years to provide better data on such interactions in addition to novel fishing methods and practices that reduce them and also improve the survival of discarded individuals. This paper discusses the data currently available and the quite significant gaps that remain.  相似文献   

6.
A new oomycete was found from intertidal fallen leaves of mangroves in Japan and Thailand and is described here asHalophytophthora porrigovesica. This species is characterized by having an epapillate, ovate zoosporangium with a lens-shaped dehiscence plug-like material at the apex, and by forming an expanding long cylindrical vesicle prior to zoospore release. A key to 14 species and 2 varieties ofHalophytophthora including the new species is proposed. The subtropical (Iriomote is., Japan) strains and tropical (Thailand) strains were different in physiological properties and especially in the asexual reproduction. The subtropical strains showed a lower optimal temperature and wider range of suitable temperature and salinity for zoosporangium formation, whereas the tropical strains showed a higher optimal temperature and narrower range of temperature and salinity. These differences are explained as adaptations of the strains to the environmental conditions of their respective habitats. From the subtropical mangroves, six strains of the new species have been isolated only from submerged leaves ofSonneratia alba, while several strains have been isolated from tropical mangroves from the leaves of three species of mangrove trees,S. alba, Bruguiera gymnorrhiza andAvicennia alba. This indicates a change of taxon selectivity (host specificity) with the geographical distribution.  相似文献   

7.
The structure of the snake community was studied between 1996 and 2000 on a transect in the mangrove ecological zone of southern Nigeria, West Africa. In three major habitats, both taxonomical diversity and frequency of observations in relation to sampling effort were investigated. In general terms, the complexity of the snake community appeared less than in other habitats of the same geographic region (i.e. swamp forest and forest–plantation mosaics). In fact, only eighteen species were recorded, whereas 43 species are known to inhabit neighbouring habitats. A Principal Component Analysis allowed arrangement of the various species into two main groups in relation to the habitats of capture: (1) a group of species of rainforest biota (i.e. Toxicodryas blandingii, Thelotornis kirtlandii, Thrasops flavigularis, Rhamnophis aethiopissa, Gastropyxis smaragdina, Grayia smythii, Pseudohaje goldii, Python sebae), and (2) a group of species that, at least in Niger Delta, are typically linked to altered habitats, including derived savannas, plantations and suburbia (i.e. Psammophis cf. phillipsi, Philothamnus cf. nitidus, Hapsidophrys lineatus, Crotaphopeltis hotamboeia, Boaedon lineatus, Naja nigricollis, Python regius). The community structure in terms of food habits and body sizes appeared similar to those of other snake assemblages from different habitats of southern Nigeria. The conservation implications of our results are also discussed.  相似文献   

8.
报道了来自福建和深圳红树林下中国首次记录的4种硅藻,即瓜形桥弯藻Cymbella cucumisA.Schmidt、拟优美舟形藻Mzvicula elegantoides Hustedt、侧偏舟形藻N platyventris Meister和柔弱舟形藻N tenera Hustedt,同时描述了每个种类的细胞形态特征和生态分布特点。作者认为淡水硅藻瓜形桥弯藻C.cucumis在半咸水和海水的环境中也有分布(盐度〉15),应属于淡水和半咸水种。  相似文献   

9.

Small-scale reef fisheries are important commercial and subsistence activities that support the livelihoods of millions of people in tropical regions. Tropical marine fisheries typically target a diversity of species caught with a matching diversity of fishing gears and practices. Here, we explored how multiple fishing gears select for distinct functional traits of fish assemblages inside a large multiple use marine environmental protected area off northeastern Brazil. In 1833 landing interviews with local fishers, we identified 101 species, which were categorized according to six traits: body size, schooling behavior, mobility, position in the water column, diet and period of activity. Our research is the first to explore the broad patterns of gear selectivity with regards to fish functional traits for different habitat types. While gears used in reef habitats were highly selective of sedentary and benthic species that form schools with few individuals, gears used in coastal lagoons were selective of highly mobile pelagic species that form large schools. We found a low competitive interaction between different gear types, meaning there was a low overlap in trait selectivity between fishing gears. We also found direct associations between gears and fish functional traits: hooks and line targeted species that exhibit limited mobility capabilities, making these species more vulnerable to local levels of fishing effort. In contrast, nets and fish corrals targeted mobile species that exhibited a greater diversity of functional traits. Some of our results contrasted with the current literature on the topic, with differences highlighting the need for more research to clarify global patterns of trait selectivity by gear type. Our results have implications for fisheries management in northeastern Brazil: gear bans and effort caps are commonly used management measures that can foster fisheries sustainability by minimizing impacts to fish assemblage functions.

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10.
Lee  Olive H. K.  Williams  Gray A. 《Hydrobiologia》2002,481(1-3):137-145
Variation in the abundance and distribution of two species of mangrove littorinid was investigated using a nested sampling design at different spatial scales, in the two dominant seasons, in Hong Kong. The abundance of Littoraria melanostoma, which was less abundant than L. ardouiniana, showed large-scale spatial variation whilst abundance of L. ardouiniana varied on both large and smaller spatial scales and interacted with seasons, indicating that the abundance of this species varied between mangroves in summer and winter. Small-scale variation suggested a patchy distribution of littorinids within a mangrove, whilst the large-scale variation might reflect changes in physical factors possibly associated with habitat fragmentation. Investigation of the vertical distribution of the littorinids on the mangrove trees revealed that L. melanostoma were located at a lower overall level than L. ardouiniana. This zonation pattern may be a result of the morphological differences of the two species, as L. melanostoma has a thick shell, whilst L. ardouiniana has a thinner, but colour polymorphic shell. Both species of mangrove littorinid showed patchy distributions at a variety of scales and these patterns highlight the importance of using a hierarchical sampling approach when investigating spatially fragmented habitats.  相似文献   

11.
Vegetation History and Archaeobotany - Environmental changes and human activities in a mangrove ecosystem in Bang Khun Thian, south of Bangkok, the upper Gulf of Thailand were reconstructed through...  相似文献   

12.
13.
Tropical fish were collected by trawling in Yemeni waters. Age determinations were made on sections of vertebrae which were cross checked with scales. The values for the von Bertalanffy growth constants K were in the range 0.08–0.31. Total mortalities ( Z ) calculated from age compositions were in the range 0.31 to 0.67 for 11 species. The mean of 0.46 agreed closely with that derived from the formula of Pauly (1980 a ) of 0.45. Since the former included fishing mortality ( F ) in addition to natural mortality ( M ) it was suggested that a lower value be used in the Gulland (1968) yield formula: Y = 0.5 M Bo . Recruitment to the fishery for most species occurred by 3 years of age. The demersal fish stocks in Yemeni waters may not exceed 109×103 tonnes at the present time. Using a value for M of 0.3, the annual sustainable yield may be in the region of 16×103 tonnes.  相似文献   

14.
6种石斛属植物氨基酸组成及营养价值评价   总被引:1,自引:0,他引:1  
为比较不同种石斛的氨基酸组成差异,作出营养评价,使用氨基酸自动分析仪检测6种石斛的氨基酸含量,分析其必需氨基酸组成成分,并通过计算氨基酸评分(AAS)、化学评分(CS)及氨基酸比值系数分(SRCAA)等非生物指标进行营养评价。结果表明:石斛中氨基酸种类齐全、营养丰富,均含有被检测的17种氨基酸。6种石斛氨基酸总量存在差异,介于3.58%~8.09%。必需氨基酸组成总含量介于42.62%~47.23%之间,明显高于WHO/FAO模式值(35.00%),其中,化学评分显示其限制氨基酸均为半胱氨酸和蛋氨酸。6种石斛药用氨基酸含量相差较大(2.24%~5.37%),其中蜻蜓石斛含量最高,为含量最低细叶石斛的2.40倍,但在总氨基酸中所占的比例基本一致(60.96%~66.47%)。对6种石斛进行聚类分析可分为4类,其中杓唇石斛、叠鞘石斛、细叶石斛可视为高品质蛋白质种。综上所述,石斛氨基酸具有重要的营养价值,6种石斛氨基酸差异显著。该结果可为石斛营养价值评价、品种选育及药用开发提供理论指导。  相似文献   

15.
Three species of mangroves, Rhizophora stylosa, Rhizophora mangle (synonym R. samoensis) and Bruguiera gymnorhiza in the family Rhizophoraceae were studied to understand the flowering pattern, propagule development and the propagule size at maturity prior to dispersal from the mother plant. The study was conducted in the Wet and the Dry zones over two seasons in Viti Levu, the Main Island of Fiji. The flower number, number of propagules and propagule size at maturity were significantly different among three species and within species in the Dry and the Wet zones. Only 1–2% of total flowers in each species became mature propagules. This percentage was significantly lower in the Dry zone for all three species. Rhizophora stylosa produced the biggest size of propagules followed by Rhizophora mangle and Bruguiera gymnorhiza. Relatively longer and heavier propagules were recorded in the Wet zone and shorter and lighter in the Dry zone. Inter-seasonal differences were not significant for these characters. This could be mainly due to almost similar amount of rainfall, relative humidity and temperature regimes over two seasons within each zone.  相似文献   

16.
We described, through a vegetation profile, the forest structure (density, basal area, tree height, and species composition), the productivity dynamics (based on litterfall) and the species phenology of distinct physiognomic types of mangroves in three locations of the La Mancha lagoon system in Veracruz, Mexico, during a complete annual cycle. We also evaluated the microtopography and ground water salinity along the profile and their relationship with forest structure and productivity. The South location showed four physiognomic types, whose forest attributes decreased as they were farther from the lagoon shore. Productivity and environment variables significantly varied among these physiognomic types. The Center location had two physiognomic types; there were significant differences in productivity and microtopography among these types, but not in salinity. The North location included two fragments of a basin forest type, and a pasture among them; productivity significantly varied among these forests, but microtopography and salinity were statistically similar. All study sites showed the following behavior: (1) as forest structure decreased, productivity also decreased and the dominant species changed. (2) As water salinity decreased, species dominance changed and productivity increased. Reproductive structures showed a notorious seasonality during the year in all species, except in R. mangle, which showed a permanent flower and propagules production. A. germinans reproduced only in the rainy season (August and September), because of their life history characteristics, whereas L. racemosa reproduced during the months of February and March as a response of the direct entrance of the water discharges, enriched with nutrients, that come from the sugar cane and rice crops. The South location was a relatively well conserved area, whereas the two other sites showed evidences of anthropic disturbances.  相似文献   

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19.
Palaquium hansenii is described and illustrated and a key is presented to the ten species of Palaquium found in Thailand  相似文献   

20.
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