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1.
We developed a habitat model for Great Tits, Parus major minor, in an urban area of Osaka, Japan. Although Great Tits play an important role in the urban food web, there are few in most of Osaka and downtown Tokyo, areas that have low vegetation cover. We derived a habitat model for Great Tits using a logistic regression model with GIS. A bird survey was conducted twice in 85 urban parks using the line census method in the breeding season, May–July 2000. A GIS base map was created from aerial photographs. The following variables were measured for each park from public records and GIS for predicting the habitat: park properties (age, distance to the nearest mountains, distance to the nearest forest of more than 10 ha), the number of other habitats occupied by the tits within 500 m and 1 km and area of tree cover (within it and surrounding parks). Number of nearby habitats and distance from the nearest mountains and forest of more than 10 ha are variables related to the regional populations of the tits. Area of tree cover was measured for five radii (50, 100, 150, 200, 250 m) from park centers, and a logistic regression model was calculated for each of these radii. Variables were selected by a stepwise method. The best fitting model of the five models was selected using Akaike’s Information Criteria. In the bird survey, the tit was recorded in 12 parks. The areas of parks occupied by the tit were 0.56–136.0 ha (mean: 26.0 ha±42.06 S.D., n=12). Variables selected in the best fitting model were area of tree cover in a radius of 250 m from park center and the number of other habitats within 1 km as positive factors. This model shows that area of tree cover within a certain range and number of nearby populations are the keys to the distribution of Great Tits. From this model obtained, 6.0 ha (31%), 4.0 ha (20%), 2.6 ha (13%) and 1.8 ha (9%) of tree area are needed to achieve probability of 0.5 in a radius of 250 m when numbers of other habitats within 1 km was 0–3, respectively. A realistic target figure is 10% of tree cover throughout urban areas to create an ecologically sustainable city. 相似文献
2.
The avifaunas of some fragmented, periurban, coastal woodlands in south-eastern Australia 总被引:4,自引:1,他引:3
Growth of urban centres world-wide has been so dramatic over the past 100–200 years that many natural habitats have been much altered around large cities. A threatened coastal plant community, Moonah Melaleuca lanceolata woodlands, has been largely destroyed and degraded over a long period by the growth of suburbs into the desirable coastal areas on the fringes of the two main cities of Vic., Australia (Melbourne and Geelong). Here, we describe the avifaunas of 19 remnants of coastal Moonah woodland. The largest remnant is about 50 ha and this was used as a site for positioning ‘virtual’ remnants against which we could compare the avifaunas of the more common size-range of real remnants (≤10 ha). Although remnant habitat structure differed consistently between virtual and real remnants, these differences were not sufficient to alter the native avifaunas in constitution or bird densities. However, species richness was higher in 10 ha and in 2 ha remnants than in 1 ha remnants. Of seven landscape-context variables, only one influenced the avifauna: species richness declined as the degree of urbanization increased (measured by roof-counts). Exotic bird species have not colonized the remnants to a great degree (four species [of 38 in total], 8% of total records). 相似文献
3.
The rate of soil erosion in pine forests (Pinus halepensis) located in the Southeast of Madrid has been estimated using dendrochronological analysis based on the change in ring-growth pattern from concentric to eccentric when the root is exposed. Using 49 roots spread across five inclined areas, it has been found that the length and direction of the hillsides, as well as their vegetation cover affect the rate of erosion, while the slope itself does not. The erosion rates found for the different areas studied vary between 3.5 and 8.8 mm year(-1), that is between 40 and 101 t ha(-1) year(-1) respectively. These values are between 2 and 3 times greater than those predicted by USLE, for which this equation underestimates soil loss for Central Spain's Mediterranean conditions. Nonetheless, both methods (using dendrochronology to determine actual soil loss and theoretical prediction with USLE) are able to establish the same significant differences among the areas studied, allowing for the comparative estimate of the severity of the area's erosion problem. 相似文献
4.
Severe competition for water and augmented agricultural and urban development in Israel have modified and destroyed wetland habitats. Using historical maps, we mapped the past extent of swamps and natural rain pools along the central coastal plain of Israel and compared this with the present extent as reflected in reports, field surveys and satellite images. Out of 192 swamps and rain pools recorded in historical sources, only 18% (35) still exist today. Extrapolation from 69 new records of rain pools (missing in historical sources), suggests that in the 19th century, before many of the wetlands were drained, transformed to agricultural land, or built over, the number of wetland habitats in the coastal plain was threefold higher. In addition to reduction of wetland number, human activity has also diminished wetland size. In rainy winters wetland areas in the coastal plain in the past were an order of magnitude larger than they are today (27.6 and 2.4 km2, respectively). At present, the existing natural water bodies along the coastal plain are temporary, small, and surrounded by built-up areas and roads. The grave state of the wetlands in Israel underscores the urgent need for protection of the remnant wetland sites. Following the successful example of wetland restoration in the Hula Valley, we recommend restoring various historical wetlands that have been drained. 相似文献
5.
The assessment of restoration of habitat in urban wetlands 总被引:1,自引:0,他引:1
Wetlands in urban areas are often restored in an attempt to reduce the loss of such habitats. Unfortunately, the success, or otherwise, of programmes of restoration has rarely been systematically gauged. Through not knowing whether programmes of restoration are successful or not, valuable resources potentially continue to be wasted, wetland habitats remain degraded and the methods of restoration are not assessed for future programmes of restoration.Several factors have contributed to poor assessment of restoration of urban wetlands. First, often the goals of restoration have been unrealistic because they failed to consider that wetlands in urban areas are subjected to ongoing and often large-scale anthropogenic disturbances. Second, goals of restoration often have not been clearly defined and, consequently, predictive hypotheses were not formulated to test for the success of restoration. Third, even when success of restoration has been assessed, this has not always been adequate because of inappropriate sampling design.Such problems can be overcome by treating restoration of habitat as experiments and using the knowledge gained from each project to improve future programmes of restoration. This will ensure that the remaining semi-natural habitats along coasts in urban areas can be more effectively managed. 相似文献
6.
Brisbane Water is an estuary located at Gosford, 50 km north of Sydney on the east coast of Australia. It contains seagrass, mangrove and saltmarsh habitat. As part of a more widespread trend along the southeast coast of Australia, between 1954 and 1995 saltmarsh habitat within the estuary declined by 78.2% while mangrove habitat fluctuated with initial decline, recovery and further decline to 1995 with an overall increase by 3.7% and exhibiting a marked migration of mangroves into saltmarsh areas.No single factor is responsible for the changes. A combination of both natural and human induced processes is responsible. The loss of diversity and the sustainability of mangroves and saltmarshes require a strategic planning approach towards their management. Such an approach needs to ensure that estuarine and catchment processes are considered in an integrated manner. The influence of human activities on natural processes, which affects the extent and distribution of estuarine wetlands, can also be managed through an integrated planning process. 相似文献
7.
Joanna Gray MICE Jennifer Hawkes ALI Peter Martin MLI 《Water and Environment Journal》2008,22(4):297-303
The Lower River Roding Regeneration (LRRR) project was funded by the Office of the Deputy Prime Minister (ODPM) with a contribution from the Environment Agency and was charged with achieving environmental and social gains along the highly urbanised lower 4.4 km of the River Roding. The funding allowed £1.5 million for all elements of work within a 2‐year‐period. Of the four sites constructed, two allowed significant river restoration to be achieved: Creekmouth Open Space and Frogmore Frontage. In the former, an existing flood defence was set back to create a tidal backwater. In the latter, a concrete river wall was demolished and a graded riverbank was created. A total of 1 ha of new saltmarsh was created on these two sites. The project demonstrates how multiple objectives of river restoration, flood defence, habitat creation, improved public amenity and urban regeneration can be achieved in an industrial urban area. 相似文献
8.
López-Alonso M Miranda M García-Partida P Cantero F Hernández J Benedito JL 《The Science of the total environment》2007,372(2-3):668-675
Many different species have been used in environmental biomonitoring studies in diverse habitats including forest, farmland, and urban and sub-urban areas. However, there is little information on domestic animals living in rural or urban habitats and exposed to the same pollutants as the human population. In this connection, pets could prove to be good indicators of human metal exposure since they closely share the same environment as their owners, and are therefore exposed, at least in part, to the same pollutants. The present study investigated toxic metal exposure in dogs in NW Spain and compared metal exposures between dogs from rural and urban habitats, considering the influence of diet, sex and age. Samples of liver and kidney from 57 male and female dogs, aged between 6 months and 18 years, were collected after euthanasia at veterinary clinics. Samples were acid-digested and metal concentrations determined by ICP-MS. Geometric mean concentrations of metals in the liver and kidney (microg/kg wet weight) were 12.6 and 15.9 for arsenic, 58.0 and 175 for cadmium, 32.7 and 53.4 for mercury, and 57.7 and 23.1 respectively. Hepatic lead concentrations were significantly higher (p<0.05) in dogs fed commercial diets than dogs fed home-made feed (32%) or a mixture of commercial and home-made feeds (95%). Mercury concentrations in the kidney were significantly higher (3-fold, p<0.05) in dogs from urban areas than in dogs from rural areas. Cadmium levels in kidney were significantly higher (p<0.05) in females (67%) and increased with age (p<0.001). Although no human samples were obtained in this study and no direct correlations between dogs and human metal exposure have been conducted, given our results pets could be suggested as surrogate indicators of human metal exposure. 相似文献
9.
Summer farming was formerly an important part of Norwegian husbandry and mountain areas have been used for grazing for hundreds of years. A decline in summer farming practices, during the twentieth century, has caused a large-scale encroachment of trees and shrubs leading to extensive landscape changes and decreased biodiversity. Therefore, in order to maintain the biodiversity in summer farm mountain areas, it is now necessary to detect, map and monitor remaining species-rich fragments, i.e. key habitats. It is also important to identify still grass- and herb-rich areas that can be successfully restored for grazing because of a new interest for summer farming. Field surveys in the re-growing mountain areas are extremely time consuming, as the concomitant terrain renders movement by foot arduous. A method was thus developed for detection of key-habitats and other grass and herb-rich habitats in such areas based on interpretation of coloured infrared aerial photographs (CIR). In addition, black-and-white aerial photographs, taken nearly 40 years ago, were used to identify past open land and pastures and thus in combination with the modern ones allow the identification of areas that exhibit a continuity in grazing. Interpretation keys were developed and vegetation maps were constructed. The interpretation from the aerial photographs was compared to detailed field control and the method was found to be efficient and accurate. The method gave useful information about the landscape history and continuity of grazing. The cattle’s movements were traced by GPS equipment mounted on a collar on the leading cattle, and their movements were later transferred to a map and analysed together with the vegetation map in a GIS. The results show that the cattle preferred to graze in the areas identified as most valuable and species rich. The developed method also makes it possible to identify areas for which pasture-restoration might be successfully achieved. Furthermore, the study revealed that there is a high correspondence between key habitats in the summer farming areas and grazing preferences of the cattle. 相似文献
10.
Recent urban ecological research shows high species numbers in slowly developed cities and towns. Urban development is known to fragment, change and weaken urban biodiversity. Conservation areas have been the main tool in protecting threatened species both in rural and urban municipalities in Finland. However, very little is known about how successful conservation areas are in protecting rare and threatened species and their habitats in boreal cities and towns. Helsinki, the capital of Finland, is a rapidly urbanising hemiboreal city, which has a high number of vascular plant species in both native and urban biotopes. One and 0.25 km2 grid square maps and simple overlay methods are being used to analyse data on species occurrence and land use. Total species number, a rarity index and historical and threatened groupings are used to classify species and their habitats. At present, conservation areas can protect only a small proportion of threatened species in Helsinki. More protection areas, green areas in future land-use decisions and new management goals are needed to protect the biodiversity of existing vascular plant species. 相似文献
11.
KWOK Siu Man 《景观设计学(英文)》2020,8(4):152
Land reclamation and dredging have a damaging effect on marine and coastal ecology. This study rationally analyzes the conflicts in the approved environmental impact assessment (EIA), including the negligence of the direct and indirect effects on coastal and marine habitats, the short circuit of the EIA procedures among stakeholders, and the insufficient marine environmental restoration schemes. This study also promotes awareness among the stakeholders so they will understand the direct and indirect effects of land reclamation on marine and coastal ecosystems, as well as the indications if they follow the EIA procedures, and implement a responsive marine bioremediation before and during the dredging process. By taking the Ocean Flower Island in Hainan, China as an example, this study applied the responsive oyster-seagrass-coral filtration bed system before and during the dredging process to maintain the water turbidity and suspended sediment concentration below the tolerance limits of the coral reefs in the adjacent areas. 相似文献
12.
Measurements of anthropogenic radionuclides in marine sediments can provide good estimates of past and present radioactive contamination of the marine environment. The Barents Sea is one of the world's richest ocean areas, and it is therefore of major interest for Norwegian fisheries to document the levels of radioactive contamination of this and adjacent ocean areas. In this study, concentrations of 137Cs, 238Pu, (239,240)Pu and 241Am were measured in marine sediments collected mainly in the Spitsbergen-Bear Island region. Additional samples collected in the deep Norwegian Sea and near the Greenland ice-edge have been included for comparison. The highest radionuclide levels were found near Spitsbergen, reaching over 50% higher than in adjacent areas. Determinations of the mineral content and particle size distribution indicate a relation between the content of clay minerals and radionuclide levels. The present study confirms earlier observations of elevated levels of 137Cs in sediments in the Spitsbergen-Bear Island area and documents elevated levels of 238Pu, (239,240)Pu and 241Am in these sediments. Using an exponential curve fit based on determinations of unsupported 210Pb in sediment cores, sedimentation rates of 0.28, 0.05 and 0.26 cm year(-1) were calculated at locations south of Spitsbergen, near the Greenland ice-edge and in the deep Norwegian Sea, respectively. 相似文献
13.
Kazi Mohammad Masum Mohammad Nabidul Islam Narayan Saha Md. Zobaer Hasan Asyraf Mansor 《Landscape Research》2016,41(3):330-343
Land grabbing has become the major problem in all the protected forest areas of Bangladesh during the last two decades. The study was conducted in Bhawal National Park, the tropical moist deciduous Sal (Shorea robusta C.F. Gaertn) forest ecosystem of Bangladesh. This area is going through a critical situation caused by industrial revolution. Already, 255.3 ha forest lands have been grabbed by 354 illegal industrial set-ups from the study area. In this study, grabbing of protected forestland by industries, their types, future grabbing trends, increasing population inside the forest area, causal factors of grabbing and impact on biodiversity have been analysed. Increasing practical conservation efforts supported by strong political will and ordinance for specific areas is essential to conserve the protected areas. Community-based conservation approaches need to be applied for mass awareness regarding the value of this ecosystem for sustainability. 相似文献
14.
Landscapes, tourism, and conservation 总被引:1,自引:0,他引:1
Burger J 《The Science of the total environment》2000,249(1-3):39-49
One key aspect of global change is a decrease in ecological integrity as more and more landscapes are developed, leaving a mosaic of intact refuges and degraded patches that may not be sufficient for conserving biodiversity. While increases in human population and shifts in the distribution of people affect land use, the temporary movement of people can have major implications for conservation and biodiversity. Three examples are presented where recreation/tourism can enhance the conservation of land on a landscape scale, leading to habitat protection and biodiversity preservation: (1) Shorebirds often require a matrix of different habitat types during migratory stopovers, and ecotourism can serve as a catalyst for landscape scale protection of habitat. (2) Riparian habitats can serve as corridors to link diverse habitat patches, as well as serving as biodiversity hotspots. (3) Remediation and rehabilitation of contaminated lands, such as those of the US Department of Energy, aimed at developing recreational activities on the uncontaminated portions, can be the most economical form of re-development with no increase in human or ecological risk. Since large areas on many DOE sites have been undisturbed since the Second World War, when they were acquired, they contain unique or valuable ecosystems that serve an important role within their regional landscapes. In all three cases the judicious development of recreational/tourist interests can encourage both the conservation of habitats and the wise management of habitats on a landscape scale. While some species or habitats are too fragile for sustained tourism, many can be managed so that species, ecosystems and ecotourists flourish. By contributing to the economic base of regions, ecotourists/recreationists can influence the protection of land and biodiversity on a landscape scale, contributing to ecosystem management. The human dimensions of land preservation and biodiversity protection are key to long-term sustainability, and ecotourists/recreationists can be one management option. 相似文献
15.
在北京分布的受胁鸟类主要分布在平原区,而平原区为城市发展的主要区域,因此,在城市管理中融入受胁鸟类保护的内容十分必要。以北京市平原区分布的24种受胁鸟类为研究对象,以鸟类对栖息地的需求为分类依据,结合国家土地利用分类标准,采用人工目视解译法,在北京市平原区的高清卫星影像图上识别出5类一级鸟类栖息地和17类二级鸟类栖息地,得到北京市平原区鸟类栖息地分布图。使用24种受胁鸟类的空间分布模型掩膜鸟类栖息地分布,得到24种受胁鸟类的预测空间分布,叠加之后获得受胁鸟类丰富度分布格局,结果显示,水域是受胁鸟类丰富度最高的栖息地。将受胁鸟类丰富度分布格局与北京市国家级和市级自然保护区分布叠加进行空缺分析,结果显示:1)北京市的自然保护区多分布在山区,不能有效保护受胁鸟类;2)受胁鸟类的保护与平原区的城市建设、绿地管理关系密切。采用分区统计方法,计算各类栖息地中分布的平均鸟类种类数,作为栖息地保护行动优先级指标,得出湖泊、水库、坑塘、滩地、沼泽地等湿地区域是具有最高保护优先级的栖息地类型,在保护实践资源充足的情况下,应对各类栖息地开展综合保护。该研究首次为北京城市区域受胁鸟类保护提出空间参考和管理建议。 相似文献
16.
This paper presents a geographic information system (GIS)-based multi-criteria decision making approach for forest conservation planning at a landscape scale. This approach enables decision makers to evaluate the relative priorities of conserving forest areas based on a set of preferences, criteria and indicators for the area. Compromise programming techniques are used to integrate the forest conservation priority maps of decision groups where a separation distance is calculated. A clustering analysis was applied to identify potential conservation areas as the basis of delineating potential new protected areas. The study was conducted in the Kinabalu area, Sabah, Malaysia where two polygons neighboring the Kinabalu Park were delineated. A group of 11 polygons totaling 2050 ha has also been detected in the western part of Kinabalu Park. The study recommends the inclusion of a forest polygon (359 ha) neighboring Kinabalu Park and another (4361 ha) to the west of the park as new protected areas. A green corridor linking the potential new protected areas and Kinabalu Park should also be constructed to facilitate animal movement and interaction. This study reveals that riparian vegetation is an important aspect to forest conservation and the legislation to protect riparian zones should be strengthened. 相似文献
17.
To assess metals in biota of the Barents Sea, information is presented on concentrations of Cu, Cd, Ni, Pb and Zn in the marine inshore benthic invertebrates Gammarus oceanicus, Littorina rudis, Nucella lapillus, Mytilus edulis and Arenicola marina collected in summer 1994. For geographical comparisons, the metal content to body size relationship was taken into account due to the different body sizes found at the localities investigated. In general, our data provide further evidence for the cadmium anomaly in invertebrates from polar waters which has been frequently discussed in the literature, with Cd concentrations reaching 1 mg x kg(-1) dry wt in G. oceanicus, 7 mg x kg(-1) in L. rudis and 24 mg x kg(-1) in N. lapillus. In contrast, our results obtained for Cd in M. edulis and A. marina are largely within a world-wide reported range (1-2 and 0.2-0.9 mg x kg(-1), respectively). Although some severe Ni emissions in the Kola region (Russia) mainly from nickel smelters have been reported, we do not find indications of an enhanced Ni availability in the marine biota studied compared to other areas 相似文献
18.
Up to now, critical loads calculations for the Flemish Region were based on European background data of surrounding countries. A first attempt has been made to calculate and map critical loads for forest ecosystems in Flanders using available site-specific information. Values of current deposition were used to calculate and map exceedances. The lowest critical loads for acidification (697 eq ha(-1)year(-1)) occur in the Campine and the north of Limburg where ecosystems largely consist of coniferous forests on poor sandy soils. The dominance of coniferous forest types in the Campine is also responsible for low critical load values for eutrophication (between 536 and 971 eq ha(-1)year(-1)). In 75% of the receptor points that have been considered an exceedance of the critical load for acidification is noted, primarily in areas with high SO2 and NOx depositions, such as the north of the provinces East and West Flanders and Antwerp. The critical load for eutrophication is exceeded in all points considered. Exceedances are particularly high in coniferous forests in West Flanders, and in the north of the provinces of Antwerp and Limburg, where especially NHx depositions amount to high values. Data needed for the calculation of critical loads are still sparse in Flanders, e.g. for: (1) weathering rates of soil minerals; (2) interception and evaporation of forest ecosystems; and (3) uptake of N and basic cations by vegetation. This supplementary information will contribute to a further refining of the calculated critical loads, which constitute indispensable information in developing an emission abatement policy. 相似文献
19.
论述了几种常见特殊地区路基病害的主要类型,分析了其产生的因素,针对山区、黄土地区、盐渍土地区及软土地区路基病害进行了探讨,并提出了一些可行的治理措施,以期保障路面质量及行车安全。 相似文献
20.
鸟类热点生境判别对于掌握鸟类空间分布格局、
识别保护空缺及指引生境修复策略具有科学价值。采用最大
熵模型确定深圳湾2000与2020年的鸟类热点生境,分析鸟
类生境的变化及其与景观格局演变的关系。结果表明:1)各
环境因子对不同生态类群的鸟类影响程度各不相同,除鸣禽
以外水源距离对其他类群鸟类的影响较大,其次为高程和
年降水量;2)2020年深圳湾的鸟类热点生境占总研究区的
3%(22km2),呈现从自然保护区向城市内陆逐渐减少的趋
势,存在2km2的保护空缺;3)20年间深圳湾鸟类的热点生
境减少了7%,热点生境下降的地区主要集中在深圳湾沿海滩
涂、香港山贝河与屯门河流域中,且猛禽与游禽的生境退化最
为严重;4)鸟类热点生境面积随斑块的数量、密度、形状与用
地类型等景观指数的增加而降低,景观破碎化和景观连通性降
低是导致鸟类生境退化的主要原因。研究为深圳湾鸟类多样性
保护及生境修复提供了参考,对粤港澳大湾区协同生态保护与
城市建设的关系具有重要意义。 相似文献