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1.
We subjected transplants of eelgrass (Zostera marina) to different substrate media (high-silted soil, akadama soil, peat soil, humus soil, pond soil and natural sediment) for over 25 days under controlled laboratory conditions. Subsequently, an 80-day field transplantation experiment was conducted to assess the establishment success of transplants planted in high-silted soil, akadama soil and natural sediment. We measured plant response in terms of survivorship, morphology and productivity. Survival analysis combined with morphological and productivity assessment suggested that the optimum growing medium for the establishment of Z. marina transplants is high-silted soil. A redundancy analysis (RDA) revealed that the survival and growth of Z. marina transplants were positively related to the air-filled porosity of the substrate media and were negatively related to the organic matter content. This study will provide data that could prove helpful in successful eelgrass restoration and conservation.  相似文献   

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Black-shouldered Kite (Elanus caeruleus) is a well-known raptor that inhabits open areas such as oil palm plantation or paddy field. To determine preferable habitat and nesting site of Black-shouldered Kite in oil palm landscape, we conducted a study on Black-shouldered Kite’s nesting biology in Carey Island, Selangor, Malaysia. We divided the island into six types of habitat and conducted road-side count of Black-shouldered Kite from April 2009 to February 2011. Whenever the Black-shouldered Kite was detected, we thoroughly searched the surrounding area for their nest. In total, we have recorded forty nests. The nests were built on 15 species of trees but most of the trees shared common physical characteristics. Some novice breeders also used oil palm tree as their nesting site. Structure and building materials of nests constructed on oil palm trees were different from nests built on other trees. Of all breeding attempts, only four nests which were located in residential area adjacent to young oil palm habitat were successful. Among important characteristics of successful nesting site include taller trees with strong branches and good leaf coverage. These trees not only protect nests from predator detection (except from other predatory birds) and physical environment but also facilitate Black-shouldered Kite’s foraging activities by providing good vantage point.  相似文献   

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Sediment physicochemical properties most likely control the reforestation success on degraded mangrove sites. Our objectives were (1) to determine the nutritional status of reforested mangrove stands; (2) to investigate the effects of the redox potential (Eh) and pH on phosphorus (P) and nitrogen (N) cycling; and (3) to assess the effect of pH on P speciation. Five transects were studied in replanted stands of the Saigon River Delta, Vietnam. Spatial gradients of sediment Eh and pH were affected by the tidal regime and pyrite oxidation. Sediment Al/Fe-P correlated with Eh or pH, depending on the sediment layer, whereas Ca-P, Morgan-P (available P) and leaf P were influenced by the pH. The highest concentrations of Al/Fe-P were recorded at pH 6.5 probably due to adsorption effects. Sediment Ca-P increased strongly at pH below 4 and above 6, reflecting the different pH-dependent solubilities of individual Ca-P mineral species as shown by a newly developed method for P species quantification. A strong increase of available P and leaf P above pH 6, and positive correlations of available P vs Ca-P (P?<?0.001) and leaf P (P?=?0.004) suggest that the Morgan’s reagent for available P determination solubilizes mainly thermodynamically less stable Ca-P compounds, which seem to fuel P plant uptake. Since foliar and sediment N:P ratios were influenced mainly by pH, shifts in pH likely cause limitation transitions. Overall, sediment pH rather than Eh was found to control the nutrient status.  相似文献   

5.
Interest in mangrove rehabilitation has increased rapidly since 2003, as has awareness of the damaging effects of natural and anthropogenic pressures that contribute to mangrove loss, which is estimated at 1–2 % per annum. The major pressures are from urbanization and other development in all areas and forestry and fisheries especially where communities depend on mangroves for their livelihood. However rehabilitation success has been uncertain, reflecting gaps in integration between human and ecological components of the rehabilitation system. In particular there are government level issues of gaps and inconsistency in policy and failure in application. Some rehabilitation efforts have had limited success for several reasons including: having insufficient information, using inappropriate methods, not involving local communities, or not following all the steps in the processes that have been identified in the literature. A multi-disciplinary and integrated approach is needed to assist future planning and this needs capacity from a variety of areas in government, research and community. The review concludes with hope for a future where governments work with communities to develop policies and strategies for rehabilitating mangrove for resilience to changing environments.  相似文献   

6.
Penang Island of Malaysia is vulnerable to various natural hazards due to its hilly terrain and weather. Due to recent rapid population and economic growth, the probability of disaster associated with natural hazards has increased. This article characterizes geological and geotechnical parameters collected from field data that relate to natural hazard susceptibility. The areas of investigation were chosen so that each area lay on different geological formations. The variations in selected parameters with depth were obtained. The correlation within parameters was established and was found to be in agreement with that from other researchers. The investigation identifies parameters that can be used to evaluate the degree of hazard susceptibility.  相似文献   

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珠海淇澳岛红树林和芦苇湿地底栖硅藻群落比较   总被引:1,自引:0,他引:1  
研究了珠海淇澳岛红树林湿地和芦苇湿地2007年3月至2008年1月间底栖硅藻群落的结构及其动态特征.结果表明,两种湿地共有底栖硅藻28属113种(变种),其中红树林中检出23属95种(变种),明显高于芦苇湿地的21属42种(变种).底栖硅藻的丰度为14.3~553.5 celk cm-3,不同样地和采样期的多样性指数和均匀度指数不同,但红树林湿地高于芦苇湿地.两种湿地底栖硅藻群落的属种结构存在显著差异,红树林湿地中多以羽纹藻类,如布纹藻属(Gyrosigma)、斜纹藻属(Pleurosigma)和羽纹藻属(Pinnularia)等占优势,而芦苇湿地主要以中心藻类,如圆筛藻属(Coscinodiscus)和小环藻属(Cyclotella)等占优势.相似性分析显示,样地基质对底栖硅藻群落的影响大于季节变化的影响.  相似文献   

10.
The Bukit Merah Orang Utan Island (OUI) Foundation has been conducting behavioral and veterinary research on orangutans as an attempt at ex situ conservation. Since 2010, the Primate Research Institute, Kyoto University has been collaborating with OUI to promote environmental enrichment and infant rearing by biological mothers in addition to the continuous efforts of refining the veterinary management of the endangered species. In 2011, three Bornean orangutans (Pongo pygmaeus pygmaeus) were released on an island, called BJ Island, adjacent to OUI. This island is approximately 5.6 ha in size, and 635 trees belonging to 102 plant species were identified prior to their release. Behavioral monitoring of the released individuals has been conducted to evaluate their behavioral adaptation to the new environment. Two of the three released orangutans were born in the wild, whereas the youngest individual was born on OUI and expected to learn forest survival strategies from the two older individuals. One of the orangutans was pregnant at the time of release and subsequently gave birth to two male infants on BJ Island. The behavioral monitoring indicated that these orangutans traveled more and spent more time on trees following their release onto BJ Island. However, resting was longer for two females both on OUI and BJ Island when compared to other populations. The orangutans consumed some natural food resources on BJ Island. The release into a more naturalistic environment may help the orangutans to develop more naturalistic behavioral patterns that resemble their wild counterparts.  相似文献   

11.
Phosphorus in soil,water and sediment: an overview   总被引:10,自引:4,他引:10  
The geochemistry, availability and abundance of different forms of phosphorus in soil, water and sediments are reviewed. The present knowledge of phosphorus pathways in ecosystems and their regulation is discussed.In a drainage basin, anthropogenic phosphorus is brought into the system mainly as fertilizers and detergents. Sewer systems and outwash processes transfer the phosphorus from the terrestrial environment to the aquatic part of the ecosystem where an accumulation occurs in the sediments of the watercourse.A great part of the phosphates in soil is sorbed to soil particles or incorporated into soil organic matter. The release and export of phosphorus from uncultivated soil is a function of the geology and soil composition, but also of the air temperature, precipitation and the hydrological condition, pH etc.The solubility of phosphates is controlled by either sorption-desorption or precipitation-dissolution reactions depending on the environment in the soil or sediments. In soil and sediments with large amounts of iron and aluminium hydrous oxides, sorption-desorption reactions are largely responsible for determining the level of orthophosphate in the solution at equilibrium.Algal availability of phosphorus associated with soil-derived materials present in aquatic systems deserves more research. In addition, processes responsible for transport of phosphorus from cropland to aquatic systems and chemical and microbial transformations of phosphorus in lakes and streams deserve more attention.  相似文献   

12.
This paper examines the outcome of four different procedures for quantifying small-scale association patterns in vegetation, with respect to data from Church Island salt marsh, Menai Bridge, N. Wales. A main aim is the evaluation of two plot-less techniques, proposed by Stowe & Wade (1979). The first examines frequencies of juxtaposition, the second the frequencies of target species in the regions of occurrence of other species. The results of these analyses are compared with those of two plot-based techniques. A Reciprocal averaging ordination is also employed to describe medium-scale distributional pattern within the data set.Of the two plot-less methods, the species-region method is found to be more useful, particularly because it is capable of detecting asymmetric relationships. When using the recommended collapsed data format the plot-less methods operate at an inconsistent spatial scale approximating to the mean run or clump size of species along the sampling transects. This allows detection of sociological patterns but may obscure environmental relationships. The small-scale relationships depicted by the plot-less methods are in cases in accord with the plot-based results at a range of scales, in other cases they differ: in each circumstance providing insights into the nature of interspecific relationships.Inter-specific pattern in salt marsh vegetation has rarely been studied. The methodology employed here shows that relationships do exist at the small scale, and may allow hypothesis generation with respect to their causality and their role in the dynamics of the marsh system.  相似文献   

13.
The spatial distribution of basidiocarps provides much information on the dispersal abilities, habitat preferences, and inter- and intraspecific interactions of aphyllophoraceous fungi. To reveal the spatial distribution and resource utilization patterns of aphyllophoraceous fungi in Malaysia, we conducted field observations in a primary forest in 2006 and analyzed the relationships between the abundance of eight dominant fungal species and various environmental factors. The topographical characteristics were significantly patchily distributed at the 100-m scale, whereas woody debris and most fungal species were distributed randomly. Although the dominant fungal species differed among the decay classes and diameters of the woody debris, the abundance of a few dominant species was significantly correlated with environmental factors. Although the latter factors might affect the spatial distribution of these fungi, the effects appear to be so small that they would not create an aggregated distribution at a few 100-m scales.  相似文献   

14.
珠海淇澳岛红树林湿地薇甘菊危害情况和发生因素研究   总被引:1,自引:0,他引:1  
为探讨珠海市淇澳岛中薇甘菊对湿地系统可持续发展的危害,以随机踩踏调查发现薇甘菊入侵红树林,造成红树林主要建群不同程度的种生长受抑.根据薇甘菊发生地点的土壤指标测定结合广东地区薇甘菊发生与人类活动和环境因子的关系建立数学模型,推测薇甘菊爆发主要原因和人类不适当的开发活动破坏当地森林资源有关.提示外来入侵生物破坏当地生态平衡.造成生物多样性下降,严重危害湿地的可持续发展,同时湿地本身的生态系统不完整性更加大了生物入侵的可能性,迫切需要采取保护措施维护湿地正常可持续发展.  相似文献   

15.
Capsule: Anthropogenic factors were identified as the main threats to wild birds in Gran Canaria.

Aims: To analyse the causes of morbidity and mortality in a large sample of selected orders of birds admitted to the Tafira Wildlife Rehabilitation Centre (TWRC) in Gran Canaria over 11 years, and to analyse the outcomes of such rehabilitation.

Methods: The records of 2390 birds were analysed. Ten primary causes of morbidity were identified: trauma, metabolic/nutritional disorder, orphaned young birds, infectious/parasitic disease, crude oil, poisoning/intoxication, glue trapping, captivity, other causes, and unknown/undetermined. The rates of the final outcome categories (euthanasia Er, unassisted mortality Mr, release Rr, and permanent captivity Cr), the time until death, and the length of stay were studied.

Results: The Eurasian Stone-curlew Burhinus oedicnemus was the species most frequently admitted (20.29%), followed by the Eurasian Blackbird Turdus merula (13.47%). The most frequent cause of morbidity was trauma (27.82%). The final outcomes of birds admitted alive were Er?=?16.69%, Mr?=?26.53%, Rr?=?54%, and Cr?=?2.76%.

Conclusions: This survey provides useful information for the conservation and welfare of these bird species. The successful release rate achieved at the TWRC emphasizes the importance of wildlife rehabilitation centres for the conservation of birds.  相似文献   

16.
Current archaeological research suggests that first human occupation of the Torres Strait Islands occurred sometime between 2500 and 3000 cal b.p., and evidence indicates that the development of agricultural mound-and-ditch systems occurred there after 1200 cal b.p. Although archaeological remains testify to the existence of a marine based subsistence economy prior to 1200 cal b.p., the potential presence of earlier prehistoric horticultural signatures has yet to be adequately examined. This study investigates such evidence through a preliminary application of fossil phytolith and starch grain analysis using excavated sediments from two archaeological sites on Dauar Island, eastern Torres Strait. The results show the early presence of yam (Dioscorea sp.), and Musa species not endemic to the island. The occurrence of these edible plant types in association with carbonised phytoliths and anthropogenic shell and bone deposits may be indicative of a combined insular horticultural and marine subsistence system on Dauar Island. We suggest that with a larger and appropriate phytolith reference set for the research area, there is a potential to more clearly define human induced changes to vegetation and patterns of subsistence in the Torres Strait Islands.  相似文献   

17.
The use of certain methods and techniques of periphyton research has been evaluated in connection with the study of periphyton on nymphaeid aquatic plants. Separation techniques explored are based on a combination of mechanical and chemical forces, on enzymatic action and on the chelating activity of EDTA. Mechanical separation by the application of superficial film is treated apart, because it is the only technique conserving the original pattern of periphyton. The means used to examine periphyton in situ consist of bleaching, epifluorescence and scanning electron microscopy.In the end, it is concluded that not one of the techniques is fully satisfactory. However, a combination of techniques may provide sufficient data to obtain an overall picture of species composition, microdistribution and architecture of a periphyton community.Contribution no. 30 of the nymphaeid project.Contribution no. 30 of the nymphaeid project.  相似文献   

18.
1. Temperature and many other physical and chemical factors affecting CO2 production in lake sediments vary significantly both seasonally and spatially. The effects of temperature and sediment properties on benthic CO2 production were studied in in situ and in vitro experiments in the boreal oligotrophic Lake Pääjärvi, southern Finland. 2. In in situ experiments, temperature of the water overlying the shallow littoral sediment varied seasonally between 0.5 and 15.7 °C, but in deep water (≥20 m) the range was only 1.1–6.6 °C. The same exponential model (r2 = 0.70) described the temperature dependence at 1.2, 10 and 20 m depths. At 2.5 and 5 m depths, however, the slopes of the two regression models (r2 = 0.94) were identical but the intercept values were different. Sediment properties (wet, dry, mineral and organic mass) varied seasonally and with depth, but they did not explain a significantly larger proportion of variation in the CO2 output rate than temperature. 3. In in vitro experiments, there was a clear and uniform exponential dependence of CO2 production on temperature, with a 2.7‐fold increase per 10 °C temperature rise. The temperature response (slope of regression) was always the same, but the basic value of CO2 production (intercept) varied, indicating that other factors also contributed to the benthic CO2 output rate. 4. The annual CO2 production of the sediment in Lake Pääjärvi averaged 62 g CO2 m?2, the shallow littoral at 0–3 m depth releasing 114 g CO2 m?2 and deep profundal (>15 m) 30 g CO2 m?2. On the whole lake basis, the shallow littoral at 0–3 m depth accounted for 53% and the sediment area in contact with the summer epilimnion (down to a depth c. 10 m) 75% of the estimated total annual CO2 output of the lake sediment, respectively. Of the annual production, 83% was released during the spring and summer. 5. Using the temperature‐CO2 production equations and climate change scenarios we estimated that climatic warming might increase littoral benthic CO2 production in summer by nearly 30% from the period 1961–90 to the period 2071–2100.  相似文献   

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Andrzej  Dyrcz 《Ibis》1984,126(1):59-66
Information on the breeding biology of Neotropical swallows is scarce (Bent 1942, Ricklefs 1971, Ridgely 1976). The aim of this study was to determine some details of breeding biology of Neotropical swallows for comparison with temperate zone species.  相似文献   

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