42 resultados para Farmlands


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Following landscape change, species invasions and extinctions may lead to biotic homogenisation, resulting in increased taxonomic and functional similarity between previously distinct biotas. Biotic homogenisation is more likely to occur in landscapes where the matrix contrasts strongly with native vegetation patches. To test this, we examined the distribution of ground-active beetles in a landscape of remnant Eucalyptus open woodland patches where large areas of lower contrast matrix (farmland) are being transformed to high-contrast pine plantations in south-eastern Australia. We sampled beetles from 30 sites including six replicates of five categories; (1) remnants adjacent to farmland, (2) remnants adjacent to plantation, (3) farmland, (4) plantation, and, (5) remnants between pine plantation and farmland. Community composition in the pine matrix was similar to native patches embedded in pine (ANOSIM, Global R=. 0.49, P<. 0.000), which we suggest is due to biotic homogenisation. Remnant patches with edges of both farmland and pine plantation did not represent an intermediate community composition between patches surrounded by either matrix type, but rather a unique habitat with unique species. Farmland supported the greatest number of individuals (. F=. 9.049, df. =. 25, P<. 0.000) and species (. F=. 5.875, df. =. 25, P=. 0.002), even compared to native remnant patches. Our results suggest that matrix transformations can reduce species richness and homogenise within-patch populations. This may increase the risk of species declines in fragmented landscapes where plantations are not only replacing native vegetation patches, but also other matrix types that may better support biodiversity. Our findings are particularly concerning given expanding plantation establishment worldwide.

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Mode of access: Internet.

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Mode of access: Internet.

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Mode of access: Internet.

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Title in right upper margin: Important farmlands maps.

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Time Alone is the introductory image to the exhibition Lightsite, which toured Western Australian galleries from February 2006 to November 2007. It is a five-minute-long exposure photographic image captured inside an abandoned building which the author converted into a camera obscura. It depicts an inverted image of the outside environment and the text 'time' - which is constructed by torch-light within the building interior and during the photographic exposure. The image evokes isolation and the temporality of inhabitation within the remote farmlands of the Great Southern Region of Western Australia: the region of focus for all of the twelve works in Lightsite. Indeed the owner of this now-abandoned house passed away and was not found for a week - bringing poignancy to the central theme of this creative work.

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The issue of the usefulness of different prosopis species versus their status as weeds is a matter of hot debate around the world. The tree Prosopis juliflora had until 2000 been proclaimed weedy in its native range in South America and elsewhere in the dry tropics. P. juliflora or mesquite has a 90-year history in Sudan. During the early 1990s a popular opinion in central Sudan and the Sudanese Government had begun to consider prosopis a noxious weed and a problematic tree species due to its aggressive ability to invade farmlands and pastures, especially in and around irrigated agricultural lands. As a consequence prosopis was officially declared an invasive alien species also in Sudan, and in 1995 a presidential decree for its eradication was issued. Using a total economic valuation (TEV) approach, this study analysed the impacts of prosopis on the local livelihoods in two contrasting irrigated agricultural schemes. Primarily a problem-based approach was used in which the derivation of non-market values was captured using ecological economic tools. In the New Halfa Irrigation Scheme in Kassala State, four separate household surveys were conducted due to diversity between the respective population groups. The main aim was here to study the magnitude of environmental economic benefits and costs derived from the invasion of prosopis in a large agricultural irrigation scheme on clay soil. Another study site, the Gandato Irrigation Scheme in River Nile State represented impacts from prosopis that an irrigation scheme was confronted with on sandy soil in the arid and semi-arid ecozones along the main River Nile. The two cases showed distinctly different effects of prosopis but both indicated the benefits to exceed the costs. The valuation on clay soil in New Halfa identified a benefit/cost ratio of 2.1, while this indicator equalled 46 on the sandy soils of Gandato. The valuation results were site-specific and based on local market prices. The most important beneficial impacts of prosopis on local livelihoods were derived from free-grazing forage for livestock, environmental conservation of the native vegetation, wood and non-wood forest products, as well as shelterbelt effects. The main social costs from prosopis were derived from weeding and clearing it from farm lands and from canalsides, from thorn injuries to humans and livestock, as well as from repair expenses vehicle tyre punctures. Of the population groups, the tenants faced most of the detrimental impacts, while the landless population groups (originating from western and eastern Sudan) as well as the nomads were highly dependent on this tree resource. For the Gandato site the monetized benefit-cost ratio of 46 still excluded several additional beneficial impacts of prosopis in the area that were difficult to quantify and monetize credibly. In River Nile State the beneficial impact could thus be seen as completely outweighing the costs of prosopis. The results can contributed to the formulation of national and local forest and agricultural policies related to prosopis in Sudan and also be used in other countries faced with similar impacts caused by this tree.

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The purpose of this study was to produce information on and practical recommendations for informed decision-making on and capacity building for sustainable forest management (SFM) and good forest governance. This was done within the overall global framework for sustainable development with special emphasis on the EU and African frameworks and on Southern Sudan and Ethiopia in particular. The case studies on Southern Sudan and Ethiopia focused on local, national and regional issues. Moreover, this study attempted to provide both theoretical and practical new insight. The aim was to build an overall theoretical framework and to study its key contents and main implications for SFM and good forest governance at all administration levels, for providing new tools for capacity building in natural resources management. The theoretical framework and research approach were based on the original research problem and the general and specific aims of the study. The key elements of the framework encompass sustainable development, global and EU governance, sustainable forest management (SFM), good forest governance, as well as international and EU law. The selected research approach comprised matrix-based assessment of international, regional (EU and Africa) and national (Southern Sudan and Ethiopia) policy and legal documents. The specific case study on Southern Sudan also involved interviews and group discussions with local community members and government officials. As a whole, this study attempted to link the global, regional, national and local levels in forest-sector development and especially to analyse how the international policy development in environmental and forestry issues is reflected in field-level progress towards SFM and good forest governance, for the specific cases of Southern Sudan and Ethiopia. The results on Southern Sudan focused on the existing situation and perceived needs in capacity building for SFM and good forest governance at all administration levels. Specifically, the results of the case study on Southern Sudan presented the current situation in selected villages in the northern parts of Renk County in Upper Nile State, and the implications of Multilateral Environmental Agreements (MEAs) and of the new forest policy framework for capacity building actions. The results on Ethiopia focused on training, extension, research, education and new curriculum development within higher education institutions and particularly at the Wondo Genet College of Forestry and Natural Resources (WGCF-NR), which administratively lies under Hawassa University. The results suggest that, for both cases studies, informed decision-making on and capacity building for SFM and good forest governance require comprehensive, long-term, cross-sectoral, coherent and consistent approaches within the dynamic and evolving overall global framework, including its multiple inter-linked levels. The specific priority development and focus areas comprised the establishment of SFM and good forest governance in accordance with the overall sustainable development priorities and with more focus on the international trade in forest products that are derived from sustainable and legal sources with an emphasis on effective forest law enforcement and governance at all levels. In Upper Nile State in Southern Sudan there were positive development signals such as the will of the local people to plant more multipurpose trees on farmlands and range lands as well as the recognition of the importance of forests and trees for sustainable rural development where food security is a key element. In addition, it was evident that the local communities studied in Southern Sudan also wanted to establish good governance systems through partnerships with all actors and through increased local responsibilities. The results also suggest that the implementation of MEAs at the local level in Southern Sudan requires mutually supportive and coherent approaches within the agreements as well as significantly more resources and financial and technical assistance for capacity building, training and extension. Finally, the findings confirm the importance of full utilization of the existing local governance and management systems and their traditional and customary knowledge and practices, and of new development partnerships with full participation of all stakeholders. The planned new forest law for Southern Sudan, based on an already existing new forest policy, is expected to recognize the roles of local-level actors, and it would thus obviously facilitate the achieving of sustainable forest management.

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The phytoplankton distribution of the Shen Reservoir, Bukuru in the Jos Plateau, Nigeria was monitored at 6 depths. Higher floral abundance occurred within the upper 00-03 meters with highest values at the first 1 meter. Bacillariophyceae and Dinophyceae recorded higher values in March-April with lower values in July and January respectively. Phytoplankton were most abundant in the rainy season. Secchi disc transparency was lowest in the peak of the rainy season (July) due to higher levels of suspended matter resulting from the increased run-off from surrounding farmlands of allochthonous materials as well as higher levels of phytoplankton population arising from the former factor. The low water temperature of December/January 15 degree C plus or minus 2 degree C might have depressed growth among the major groups of plankters but enhanced rapid multiplication of the Chlorophyta, Trachelomonas which showed a bloom at this season

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The production and productivity of a water body is largely dependent on its quality. One major source of water pollution is from the agrochemicals from nearby farmlands. The quality of water in the Obafemi Awolowo University Teaching and Research Farm Reservoir (Ile-Ife, Nigeria) was monitored between October, 1993 and March, 1994. Structured questionnaires were administered to obtain information on the types of agrochemicals in use on the farm. Water samples were collected fortnightly for analyses of the physico-chemical parameters and ionic content of the water. Investigation revealed that 21 agrochemicals had been in use on the farm. The physico-chemical parameters of the water showed that the water was very poor in nutrient. The high concentration of ammonium ion contents of the water shows an indication that the residues of certain agrochemicals got into the water to pollute it. Agrochemicals should be used with great caution on farmlands especially in areas close to water bodies from which man obtains fish and other proteinous foods. This paper also suggests a regular monitoring of water quality of reservoirs in order to pick the earliest signs of pollution

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Black-and-white snub-nosed monkeys (Rhinopithecus bieti) are endemic to the Trans-Himalayas in Northwest Yunnan and Southeast Tibet between the upper Yangtze and Mekong Rivers. Based on field surveys and previous reports, we identified the dark-coniferous forest, the mixed coniferous and broadleaf forest, and oak patches as suitable habitats (SH) for the monkeys. Summer grazing lands (SGL), which were made by local people cutting and burning the dark-coniferous forest at the high altitude belt, replaced SH. To have a general view of the status of the SH in Yunnan, we estimated the areas of SH and SGL from satellite images in 1997, and compared with areas estimated from aerial photo-based maps (ca. 1958). The work resulted in: 1) the area of SH was 4,169 km(2) in 1997; 2) SGL was 1,923 km(2); 3) during the past 40 years, the area of SH decreased by 31% (1,887 km(2)), and SGL increased by 204% (1,291 km(2)); and 4) the mean size of forest patches decreased from 15.6 to 5.4 km(2). In addition, the area of SGL is positively correlated to local human population (R-2 greater than or equal to0.53), implying that the reduction and fragmentation of habitat for Rhinopithecus bieti is a result of population growth of humans, who mostly employ traditional modes of production. Only 11 monkey groups remained in the changing habitat. Considering that forests at lower elevation were also encroached upon by farmlands in a similar way, the forest ecosystem is highly threatened. The destruction will continue unless there is a change in the mode of production in the region.

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Goal, Scope and Background. As one of the consequences of heavy metal pollution in soil, water and air, plants are contaminated by heavy metals in some parts of China. To understand the effects of heavy metals upon plants and the resistance mechanisms, would make it possible to use plants for cleaning and remediating heavy metal-polluted sites. Methods. The research results on the effects of heavy metals on plants and resistant mechanisms are compiled from Chinese publications from scientific journals and university journals, mostly published during the last decade. Results and Discussion. Effects of heavy metals on plants result in growth inhibition, structure damage, a decline of physiological and biochemical activities as well as of the function of plants. The effects and bioavailability of heavy metals depend on many factors, such as environmental conditions, pH, species of element, organic substances of the media and fertilization, plant species. But, there are also studies on plant resistance mechanisms to protect plants against the toxic effects of heavy metals such as combining heavy metals by proteins and expressing of detoxifying enzyme and nucleic acid, these mechanisms are integrated to protect the plants against injury by heavy metals. Conclusions. There are two aspects on the interaction of plants and heavy metals. On one hand, heavy metals show negative effects on plants. On the other hand, plants have their own resistance mechanisms against toxic effects and for detoxifying heavy metal pollution. Recommendations and Outlook. To study the effects of heavy metals on plants and mechanisms of resistance, one must select crop cultivars and/or plants for removing heavy metals from soil and water. More highly resistant plants can be selected especially for a remediation of the pollution site. The molecular mechanisms of resistance of plants to heavy metals should be studied further to develop the actual resistance of these plants to heavy metals. Understanding the bioavailability of heavy metals is advantageous for plant cultivation and phytoremediation. Decrease in the bioavailability to farmlands would reduce the accumulation of heavy metals in food. Alternatively, one could increase the bioavailability of plants to extract more heavy metals.

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日益增强的旅游活动干扰正成为九寨沟世界自然遗产的有效保护与持续管理不可回避的挑战,已成为当前区域生态保护与经济发展的焦点问题之一。阐明相关旅游的干扰活动对核心景区植物物种组成、多样性与结构的影响是九寨沟有效保护与持续管理的必要前提和基础,然而至今少有研究。选择九寨沟与旅游活动相关的九个景点、公路建设地段以及退耕地还林地,详细调查了林下植被结构、物种组成与多样性,比较了相关旅游活动干扰与基本未受干扰地段的差异。目的是阐明九寨沟核心景区旅游干扰条件下植物多样性与群落结构及其特点,揭示旅游干扰与植被结构和生物多样的相互关系,评估九寨沟旅游管理的有效性,探索减免旅游干扰影响的对策与措施。初步结论如下。 1.旅游活动引起九寨沟核心景区植物组成和群落结构特征改变显著。栈道及公路附近许多耐荫喜湿的敏感种局部消失,而早熟禾、车前草、委陵菜等耐干旱、耐践踏、繁殖能力强的植物种群扩大;外来物种频繁出现并已少量侵入干扰相对较轻的林分深处;林下群落以草本植物为优势,灌木与苔藓植物的频度、盖度、高度以及灌木密度均有所下降。可见,大量的游人活动和景区公路建设已对九寨沟丰富的乡土植物构成极大威胁,导致其生物多样性降低。而九寨沟农耕地退耕有利于九寨沟生态环境和生物多样性保护,正逐步向稳定群落演替。 2.干扰强度的差异导致九寨沟植物所受影响的程度不同。栈道附近植物受影响的程度与游人活动频率有关,活动频率高的地段干扰强度大,对植物的影响程度重,反之植物所受的影响较轻。强度干扰地段,耐荫喜湿的物种少见,伴生植物优势地位突出,生物多样性明显降低,植物群落结构特征改变也极为显著;干扰较轻的地段,伴生物种少量出现,植物群落结构变化不明显,生物多样性略为降低,部分地区结构参数值和多样性指数有所升高。公路修建是一种强度干扰,它导致附近植物种类极为单一,草本优势种异常突出,多数植物生活力低下、生长更新能力差。 3.不同植物类群受干扰影响的程度不同。草本及苔藓植物的种类组成和多样性指数受干扰影响较大,灌木和苔藓植物的结构受干扰影响较大,苔藓植物对干扰影响最为敏感。 综合分析表明,九寨沟核心景区的管理虽然比较规范,但目前核心区热点景点段的管理仍然不够,旅游活动驱动了林下植被退化明显、物种组成显著变化、生物多样性衰退、非乡土喜光耐旱种群扩大。导致九寨沟核心区旅游活动与生物多样性保护目标尖锐冲突,进一步约束旅游活动带来的干扰,强化管理,开展林下植被恢复与非乡土喜光耐旱种群调控是九寨沟自然遗产地保护一项紧迫任务。 The increasing tourism disturbance is an unavoidable challenge to effective conservation and sustained tourist management of Jiuzhaigou Nature Reserve. It has become one of the focal problems of regional ecological protect and economic development. It is important to clarify effects of tourism disturbance on plant species composition, diversity and community structure in kernel spot for effective conservation and sustained tourist management in Jiuzhaigou, China. However, there were little studies about this yet. The study investigated the vegetation structure, species composition and diversity at nine sight spot, road area and four abandoned farmlands connecting with tourism, and compared the differences between disturbed area and undisturbed area. The purpose of the this study is clarifying the plant diversity and community structure and characteristics of the disturbed area in kernel spot of Jiuzhaigou, discovering the relation between vegetation structure and biodiversity, evaluating the effect of tourist management and exploring the measure decreasing tourist disturbance. Our results are following: 1. Tourism disturbance caused a significant change in species composition and structure of plant communities in kernel Spot of Jiuzhaigou. In the vicinity of plank and road, some native shade-tolerant or hygrophilous plants had disappeared, accompanying with the population expansion of some xerophilous and disturbance-resisting species such as Poa sp. Plantago depressa, Potentiila multicaulis and some exotic and synanthropic species. Herbs were domaint species, while frequency coverage and height of shrubs and bryophytes, and shrub density decreased. In indicated that tourist activities and build of road had adversely affected on native plant species, and led to decline in biodiversity of Jiuzhaigou Nature Reserve. Abandoned farmlands maybe conduced to entironment and biodiversity conservation. 2. Nearby the plank, influency variable of tourism disturbance on plant was alosely and positively correlated with disturbance intensity. There was companion plant species and lacked shape-loving species in heavy disturbed areas, which caused decrease in biodiversity and significant change in community structure in these places. On the contrary, in the slightly disturbed areas, some companion speices displayed and biodiversity decreased slightly, but no significant change in community structure in these areas. The biuld of road is a heavy disturbance form, which led to increase of herb species and to decrease in vitality and regeneration capacity. 3. The intensity of tourism disturbance on plant depended on plant groups. Tourism interference significantly influenced species composition and diversity index of herb and bryophyte; it also significantly influenced community structure; the bryophyte was more sensitive to tourism disturbance. Our result indicated that the management in kernel spot of Jiuzhaigou is relatively reasonable, but not adequate. Tourism speed the degradation of the vegetation under woodland, the change of the species composition, the decreaing of the biodiversity and the expanding of the exotic sunloving plant populations. The contradiction between tourism and conserving biodiversity is increasing, so enforcing management, regenerating the vegetation under woodland and adjusting the exotic sunloving arid-tolerent plant populations is a pressing work to protect the Jiuzhaigou natural legacy.

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黄土高塬沟壑区沟头溯源侵蚀非常普遍,已经对塬面地区的土地、农田、村庄民居、道路和工厂造成了严重的威胁。通过对董志塬的调查发现,影响溯源侵蚀的因素为自然和人为因素两类。自然因素主要包括降雨径流、地形地貌和土质。总结出溯源侵蚀的发生类型为水力冲刷型、陷穴诱发型、裂缝诱发型和人为诱发型。溯源侵蚀的过程从时间顺序上可分为3个阶段,主要分为水力冲刷阶段、水力和重力共同作用阶段、重力侵蚀阶段。最后,根据不同类型的沟头侵蚀与活动特点,提出了沟头的主要防护措施。