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1.
Serious soil erosion occurred in the South Downs National Park, southern England in the years 1982–2006 and details of around 400 sites are contained in a database. In 2010 we revisited 85 of the most serious sites where erosion of >10 m3 ha−1 y−1 had been recorded in order to assess land use change and any conservation measures undertaken. At 79% of the sites land use change had resulted in a reduction in the risk of erosion, most notably at 28 sites with a shift to permanent grass from winter cereals. At only 21% of sites was the risk of erosion unchanged. Twenty two farmers responsible for 66 of the sites were interviewed. Land management practices had changed on all of the fields of interest to this study since the time of the serious erosion events, to those which have the potential to lower soil erosion risk. Sixteen interviewees claimed that erosion was a motivating reason for changing their practices, due to either experiencing on or on- and off-farm impacts firsthand (12), having knowledge or suspicion of serious erosion having occurred on their land prior to their management (three), or having no knowledge of any serious erosion on their land but just wanting to reduce overall erosion risk (one). Amongst the main changes reported are changes of land use from winter cereals to grass or to overwinter stubble which have undoubtedly reduced the risk of erosion. However, some changed practices claimed by farmers, such as along-the-contour-working, earlier sowing and the use of rollers may be of little value. Furthermore, deeper analysis of farmers’ motivations regarding changes in land management practices suggests a complex picture in which a range of socio-economic influences come into play over time including financial incentives offered by agri-environmental schemes which were found to be an important driver of change. Future changes in farming economics may therefore undermine the reduction in erosion risk in the longer term.  相似文献   

2.
The “polluter pays principle” (PPP) has been looked at from the perspective of legal values and technical principles, namely of soil science, to evaluate the acceleration of soil erosion and the consequent development of degraded areas in the Uberaba River basin (area: 2419 km2), state of Minas Gerais, Brazil. Having accomplished this goal, the study highlights the importance of PPP for the conservation of soil and development of an ecologically equilibrated environment. The diagnosis of degraded areas was based on the coupling of a Geographic Information System with soil loss, land use conflict and tolerance to soil loss models, and revealed a preoccupying situation because an extension of approximately 905 km2 (1/3 of the basin) has been considered in advanced state of degradation potentially causing environmental damage (e.g., decline of soil fertility and hence crop production, negative impacts of soil particles export on stream and lake water quality and biodiversity of riverine ecosystems). Facing this problem, a legal framework standing on doctrinaire principles, federal laws and the Brazilian Constitution has been proposed whereby the protagonists of soil degradation are called to assume responsibility as well as the costs of repairing this negative condition. Although the study has been carried out on a specific country under pre-defined settings, the rationale behind the proposals can easily be transposed to other scenarios because the scientific methods on which soil degradation has been defined and mapped are generally applicable, while the suggested legal values are currently applied to many regions on the planet.  相似文献   

3.
Natural vegetation enhances the value of agricultural landscapes for people and wildlife. However, the role of anthropogenic versus topographic factors in driving the extent of natural vegetation cover within agricultural lands at large spatial scales remains unexplored. I assessed the influence of anthropogenic and topographic variables on the extent of agricultural mosaics with high natural vegetation cover in the country of Turkey where a large extent of natural and semi-natural vegetation is maintained by traditional agriculture. GIS layers depicting human land use, elevation, slope, roads and population data were obtained and summarized at two spatial scales, within provinces and for 100 km2 grid cells covering the country’s entire agricultural land area. Average farm size was also obtained at province level. Hierarchical Partitioning was conducted to determine the independent effect of anthropogenic and topographic variables on the variation in agriculture with high natural vegetation. Slope had the largest independent effect on the variation in the proportion of agricultural mosaic with high natural vegetation cover. The extent of agricultural and settlement area also explained much of the variation in natural vegetation across both grid cells and provinces. The proportion of natural vegetation increased as human population and road density decreased across grid cells and as average farm size decreased across provinces. These results suggest that while topography is the primary driver of natural vegetation cover within agricultural mosaics in Turkey, the pressures associated with urban development and agricultural industrialization may also influence the cultural and wildlife value of agricultural landscapes.  相似文献   

4.
选择植被覆盖度、地形坡度和土地利用类型来进行水土流失的风险度评价;试验区域为福州市第二饮用水源地山仔库区和塘坂库区;利用Landsat-7ETM 的影像,在计算归一化差分植被指数NDVI的基础上估算水源地保护区的植被覆盖度;利用栅格数字高程模型DEM,计算地表坡度;利用土地利用类型图获取保护区各地土地利用类型的分布;根据水利部部颁标准,对植被覆盖度、坡度和土地利用类型进行分级,建立水土流失风险评价模型,并在ArcGIS 9.0软件支持下,对上述各因子进行叠加分析,得到保护区水土流失评价风险评价;结果表明研究区内生态环境总体保护较好,但存在一定的水土流失现象,生态环境保护还需进一步加强.  相似文献   

5.
Studies of land use policies are commonly based on the environmental impacts or on people's direct responses to the policies. However, research on the impact of policy implementation on people's livelihood and activities and the subsequent economic development of an area is incomplete. We selected Yanchang County as an example to track land use changes and their effects on the livelihood of the local population following the implementation of a new land use policy known as the Grain for Green Project (GGP). The data were collected from statistical yearbooks, questionnaire surveys, and satellite imagery from 1990, 2000, and 2008. We found that dramatic land use changes have occurred in Yanchang County. The vegetation coverage improved significantly from 1990 to 2008, as the grassland and forest areas increased from 44.1% to 60.1% and from 17.7% to 18.4% of the total land area, respectively. The cultivated land declined from 37.3% to 20.7%. With the agricultural area and grain production decreasing from 64 × 103 tons to slightly over 20 × 103 tons per year, an increasing number of local people sought employment in towns and cities. The non-farm income increased, and the local income structure shifted. Migrant and orchard worker income contributed the most to the balance of the total household income. We narrowed our focus to discuss how the GGP accelerated the changes in the participants’ lifestyles and what might be done to sustain the long-term effects of the GGP. While the GGP has brought about considerable environmental benefits, a comprehensive study of environmental–social systems is still needed to achieve a more efficient land use policy. The research results presented in this paper demonstrate that changes in land use and people's activities were triggered by policy changes. We aim to pave the way for studies on the “policy-land-use-social development” chain and to provide references for new policies.  相似文献   

6.
In the Genil River Basin (southern Spain), agriculture is the greatest pressure on freshwater demand. Furthermore, water degradation caused by soil erosion is becoming a key environmental concern. This study aims to assess the water-related impacts of agriculture combining the use of an ecohydrological model (SWAT) with a spatiotemporal water footprint assessment to evaluate the current status of streamflow (blue water), soil water (green water) and the assimilability of sediments by streamflow (grey water footprint). The Common Agricultural Policy (CAP) requires farmers to adopt certain agricultural practices that are beneficial for the environment. Such practices could affect the conditions of available land and water resources. Because of the importance of applying the best land management practices for the maintenance of sustainable water resources, the study also infers probable water availability and water pollution level changes under different post-2013 CAP scenarios. The Genil streamflow is highly regulated, and, as a result, it is hard to discern significant changes (p < 0.05) under the proposed scenarios. However, there is a shift with afforestation measures from unproductive (i.e., direct soil evaporation) to productive water (i.e., evapotranspired water from agricultural and natural areas, excluding non-growing periods) consumption. The probability of annual evapotranspiration from natural areas being greater in afforestation scenarios than in the baseline scenario is 0.70 to 0.88, whereas the likelihood of soil water evaporation being lower is 0.60. Evapotranspiration in natural areas increases by about 521% from September to May under afforestation measures compared with the baseline scenario, whereas soil water evaporation decreases by 30% in winter. The grey water footprint and water pollution level decrease by 19% and 9%, respectively, with the highest streamflow conditions under afforestation as opposed to current conditions. However, water pollution levels of suspended solids greater than 1 indicate that the river flow is not capable of assimilating the existing sediment loads. Since land use changes and agricultural practices have a major impact on water resources, the post-2013 CAP reform can provide environmental benefits for water allocation and mitigation of water pollution. However, further efforts are required to better align the policy goals of the CAP and the Water Framework Directive.  相似文献   

7.
Oil palm plantations in Indonesia have been linked to substantial deforestation in the 1990s and 2000s, though recent studies suggest that new plantations are increasingly developed on non-forest land. Without nationwide data to establish recent baseline trends, the impact of commitments to eliminate deforestation from palm oil supply chains could therefore be overestimated. We examine the area and proportion of plantations replacing forests across Sumatra, Kalimantan, and Papua up to 2015, and map biophysically suitable areas for future deforestation-free expansion. We created new maps of oil palm plantations for the years 1995, 2000, 2005, 2010 and 2015, and examined land cover replaced in each period. Nationwide, oil palm plantation expansion occurred at an average rate of 450,000 ha yr−1, and resulted in an average of 117,000 ha yr−1 of deforestation, during 1995–2015. Our analysis of the most recent five-year period (2010–2015) shows that the rate of deforestation due to new plantations has remained relatively stable since 2005, despite large increases in the extent of plantations. As a result, the proportion of plantations replacing forests decreased from 54% during 1995–2000, to 18% during 2010–2015. In addition, we estimate there are 30.2 million hectares of non-forest land nationwide which meet biophysical suitability criteria for oil palm cultivation. Our findings suggest that recent zero-deforestation commitments may not have a large impact on deforestation in Sumatra, where plantations have increasingly expanded onto non-forest land over the past twenty years, and which hosts large potentially suitable areas for future deforestation-free expansion. On the other hand, these pledges could have more influence in Kalimantan, where oil palm driven deforestation increased over our study period, and in Papua, a new frontier of expansion with substantial remaining forest cover.  相似文献   

8.
Forest Transition Theory (FTT) suggests that reforestation may follow deforestation as a result of and interplay between changing social, economic and ecological conditions. We develop a simplistic but empirically data driven land use transition agent-based modeling platform, interactive land use transition agent-based model (ILUTABM), that is able to reproduce the observed land use patterns and link the forest transition to parcel-level heuristic-based land use decisions and ecosystem service (ES). The ILUTABM endogenously links landowners’ land use decisions with ecosystem services (ES) provided by the lands by treating both lands and landowners as interacting agents. The ILUTABM simulates both the land use changes resulting from farmers’ decision behaviors as well as the recursive effects of changing land uses on farmers’ decision behaviors. The ILUTABM is calibrated and validated at 30 m × 30 m spatial resolution using National Land Cover Data (NLCD) 1992, 2001 and 2006 across the western Missisquoi watershed, which is located in the north-eastern US with an estimated area of 283 square kilometers and 312 farmers farming on 16% of the total Missisquoi watershed area. This study hypothesizes that farmers’ land use decisions are made primarily based on their summed expected utilities and that impacts of exogenous socio-economic factors, such as natural disasters, public policies and institutional/social reforms, on farmers’ expected utilities can significantly influence the land use transitions between agricultural and forested lands. Monte Carlo experiments under six various socio-economic conditions combined with different ES valuation schemes are used to assess the sensitivities of the ILUTABM. Goodness-of-fit measures confirm that the ILUTABM is able to reproduce 62% of the observed land use transitions. However, the spatial patterns of the observed land used transitions are more clustered than the simulated counterparts. We find that, when farmers value food provisioning Ecosystem Services (ES) more than other ES (e.g., soil and water regulation), deforestation is observed. However, when farmers value less food provisioning than other ES or they value food provisioning and other ES equally, the forest transition is observed. The ILUTABM advances the Forest Transition Theory (FTT) framework by endogenizing the interactions of socio-ecological feedbacks and socio-economic factors in a generalizable model that can be calibrated with empirical data.  相似文献   

9.
Land use transitions are rated among the leading sources of greenhouse gas emissions in the tropics. They significantly challenge the functioning of ecosystems and affect multi-temporal stability of greenhouse gases such as N2O and soil properties. Studies on dynamics in nitrogen balances are essential in understanding greenhouse gas emissions such as N2O and to manage their impacts on productivity. In this study, multi-temporal Landsat images (1975, 1995 and 2012) were classified to determine land use transitions and potential drivers. The classified images were categorized into degraded and non-degraded lands and eighty sampling plots generated within the entire study area. Soil samples were then collected at 0–15, 15–30 and 30–60 cm depths on each plot and soil nitrogen determined. A regression analysis was developed to determine the influence of forest and grassland degradation on soil nitrogen. Results indicated a significant change in major land use and land cover types. Specifically, there was a decrease in areas covered by forests, woodland and grassland, however, area covered by less dense forest increased. Results also indicated variability in mean nitrogen content between degraded and non-degraded areas and depths. Furthermore, levels of degradation influence nitrogen content up to a soil depth of 30 cm. The present study is relevant in the detailed assessment of the extent of damage and threats posed to biodiversity hotspots in sub-Saharan Africa. These results are transferable to other parts of the world characterized by dynamic ecological transformation.  相似文献   

10.
Predicting soil erosion potential is important in watershed management. A rapidly growing Iranian population and climate change are expected to influence land use and soil sustainability. In recent years, northern Iran has experienced significant land use changes due to internal migration along the Caspian coast and conversion of forests and rangelands. Considering the effect of these changes in the future, the purpose of this study is to forecast land use patterns and investigate soil erosion scenarios using the Revised Universal Loss Equation and Markov Cellular Automata. Data from 1981 to 2011 were used as a baseline to estimate changes that might occur in 2030. The results reveal that the mean erosion potential will increase 45% from the estimated 104.52 t ha−1 year−1 in the baseline period. Moreover, the results indicate that land use change from forest area to settlements will be the most significant factor in erosion induced by land use change, showing the highest correlation among erosional factors. Projecting land use change and its effect on soil erosion indicate that conversion may be unsustainable if change occurs on land that is not suited to the use. The method predicts soil erosion under different scenarios and provides policymakers a basis for altering programs related to land use optimization and urban growth. Those results indicated the necessity of appropriate policies and regulations particularly for limiting land use changes and urban sprawl in areas of unfavorable soil erosion risk factors.  相似文献   

11.
Scenario analysis of urban dynamics from spatial land use models can support urban, planning and policy. An integrated modeling approach, linking assessment of urban spatial dynamics, was applied to the Santiago Metropolitan Area (SMA). The integrated land use change model combines, a logistic regression model, Markov chain, and cellular automata. This model was calibrated with data, from 1975 to 2010, and was used to make predictions for the years 2030 and 2045, using two datasets of, urban and non-urban explanatory variables. Urban change estimates showed the highest fit during the, model calibration phase. The true-positive proportion and standard Kappa value (κ) were of 99% and, 0.87 respectively when validating against an urban cover reference map from 2010. Urban growth was, equal to +27,000 ha (72%) for the period 1975–2010, and the city of Santiago is projected to, reach approximately 93,000 ha by 2045 (+43% from 2010). In the SMA the most important, urban growth pattern is peri-urban development, referring to widespread boundaries and higher, fragmentation in peripheral municipalities. Predictions for 2030 estimate that ∼15% of the projected, urban expansion will occur outside the boundary set by the current Regulatory Plan proposal. These, results demonstrate the capacity of the integrated model to establish comparisons with urban plans, and its utility to explain both the amount and constraints of urban growth. The integrated approach of, urban dynamic assessment using land use modeling is useful for spatiotemporal representation of, distinct urban development forms.  相似文献   

12.
In this paper we analyze the indirect land use change (ILUC) effects of ethanol production expansion in Brazil through the use of an inter-regional, bottom-up, dynamic general equilibrium model calibrated with the 2005 Brazilian I-O table. A new methodology to deal with ILUC effects is developed, using a transition matrix of land uses calibrated with Agricultural Censuses data. Agriculture and land use are modeled separately in each of 15 Brazilian regions with different agricultural mix. This regional detail captures a good deal of the differences in soil, climate and history that cause particular land to be used for particular purposes.Brazilian land area data distinguish three broad types of agricultural land use, Crop, Pasture, and Plantation Forestry. Between one year and the next the model allows land to move between those categories, or for unused land to convert to one of these three, driven initially by the transition matrix, changing land supply for agriculture between years. The transition matrix shows Markov probabilities that a particular hectare of land used in one year for some use would be in another use next period. These probabilities are modified endogenously in the model according to the average unit rentals of each land type in each region.We ask whether biofuel expansion is consistent with new laws, limiting forest clearing in Brazil. A simulation with ethanol expansion scenario is performed for year 2020, in which land supply is allowed to increase only in states located on the agricultural frontier. Results suggest that each new hectare of sugar cane requires only 0.14 ha of new land, with another 0.47 ha converted from pasture use. Hence policies limiting deforestation are unlikely to prevent greater ethanol production. Finally, regional differences in sugarcane productivity are found to be important elements in ILUC effects of sugar cane expansion.  相似文献   

13.
In this study, an interval fuzzy chance-constrained land-use allocation (IFCC-LUA) model is developed for sustainable urban land-use planning management and land use policy analysis under uncertainty. This method is based on an integration of interval parameter programming (IPP), fuzzy flexible linear programming (FFLP) and chance-constrained programming (CCP) techniques. Complexities in land-use planning management system can be systematically reflected, thus applicability of the modeling process can be highly enhanced. The developed method is applied to planning land-use allocation practice in Nanjing city, China. The objective of the IFCC-LUA is maximizing net benefit from LUA system and the main constraints include investment constraints, land suitability constraints, water/power consumption constraints and wastewater/solid waste capacity constraints. Modeling results indicate that desired system benefit will be between [1.34, 1.74] × 1012 yuan under the minimum violating probabilities; the optimized areas of commercial land, industrial land, agricultural land, transportation land, residential land, water land, green land, landfill land and unused land will be [290, 393] hm2, [176, 238] hm2, [3245, 4390] hm2, [126, 170] hm2, [49, 66] hm2, [1241, 1679] hm2, [102, 138] hm2, [7, 10] hm2 and [178, 241] hm2. They can be used for generating decision alternatives and thus help decision makers identify desired land use policies under various system-reliability constraints of economic development requirement and environmental capacity of pollutant. Tradeoffs between system benefits and constraint violation risks can also be tackled.  相似文献   

14.
Land use and cover (LUC) change is a major driver of ecosystem service loss worldwide. In response, policymakers have designed conservation strategies that incentivize the establishment and maintenance of LUC types associated with higher ecosystem service provision. Many of these policies also aim to promote social and economic goals such as reducing poverty. Attempts to measure the impact of policy-driven LUC change on stakeholders typically focus only on economic outcomes for landowning participants or aggregate the socio-economic outcomes of diverse groups. In this study, we applied local ecological knowledge (LEK) held by beekeepers in Costa Rica to understand the impact of policy-driven LUC change on this specific group of often non-landowning stakeholders. Beekeeping is a globally important rural livelihood and provides pollination services to crops and wild plants. We synthesized beekeeper LEK using a mixed-methods approach including apiary mapping exercises (n = 215 apiaries), questionnaires (n = 50 participants), and follow-up interviews (n = 21 participants). Our study revealed that some policy-driven LUC changes have limited beekeepers’ access to preferred land uses, such as secondary and mature forests with native trees. Participants reported concern for their livelihoods due to policy-driven spatial and temporal change of floral resources via the establishment of tree plantations, changes in pasture management, and laws that prohibit beekeeping in national parks and reserves. Our study provides evidence of unintended outcomes from land use policies, including Payment for Ecosystem Services, with disproportionate negative impacts on non-landowning residents who depend on natural resources in the landscape for their livelihoods. Our study illustrates potential inequality rising from current incentive mechanisms associated with Payments for Ecosystem Services and other conservation policies and calls for policymakers to consider LUC change impacts on non-landowning stakeholders.  相似文献   

15.
Being fertile lands, wetlands have been managed for traditional agriculture over millennia. However, the integrity and ecosystem services of wetlands are being jeopardized by intensive land-use comprising of drainage and excessive disturbance. An adhoc and intensive use of wetlands, without preserving ecological integrity is causing ecosystem disservices and threatening conversion of a large soil organic carbon (SOC) sink into a net source. Wetlands in the tropical parts of the world are distributed unevenly and represent ∼3% of the total world land area. Due to stagnancy and even reduction in rice (Oryza sativa) yield of many agricultural regions, there is a need for additional and alternative land-uses which can raise the global rice production to ∼1 billion Mg (megagram = 106g = metric ton) by 2050 from ∼497 million Mg now. Wetlands can be a viable option to advance global food security because of high soil fertility and vast geographical distribution. A ‘3-tier rice production system’ is proposed herein based on specific hydrological niche to advance global food security without degrading the ecosystem services of wetlands. In addition to increasing agronomic yield, the proposed modus operandi can also improve the livelihood security of farmers through an additional income streams by: (i) trading of SOC credits generated through adoption of conservation agriculture in littoral zones, and (ii) promoting fish and duckery culture in conjunction with deepwater rice farming. Furthermore, the proposed strategies will also set in motion the process of restoration of wetlands while enhancing C sink capacity of the ecosystems.  相似文献   

16.
The Okavango catchment is a hot spot of accelerating land use change. In particular, climate predictions, demographic developments and a growing utilization of ecosystem services and functions are expected to increase pressure on resources and land. Land use conflicts, the sustenance of precarious livelihoods, deforestation of woodland savannahs, upstream–downstream water issues and human–wildlife conflicts are among the processes that are characteristic of policy and management challenges in the region. In the Eastern and Western Kavango regions of Namibia and the Cuando-Cubango province of Angola, a unique cross-border situation exists that allows assessing how the combination of local traditions, regional land management and national policies determines spatial patterns of land use and land cover transformation processes.To map major land use types and change processes we used a set of multi-temporal Landsat-5 TM and Landsat-7 ETM+ data sets, support vector machine (SVM) classification and iterative spectral mixture analysis (ISMA) on images covering the period from 1990 to 2010. Integrating satellite imagery with literature reviews, interviews, census and household survey data, we assessed the contrasting development of resource utilization on both sides of the Okavango River. We investigated if and how policies and regulations at different levels drive land use decisions, and how these decisions manifest spatially.We found a strong and interconnected urban growth on both sides of the river. The area around Rundu has constantly been evolving to become Namibia's second largest city, also functioning as a hub of development and transborder commerce with opposing Calai. This trend was found to affect adjacent settlement areas and cause widespread conversion of woodland savannahs to agricultural land or their utilization for timber extraction. The conversion of woodland savannah to arable land was by far the dominant land use change process on both sides of the river, with a total conversion area of 460 km2 (Namibia) and 293 km2 (Angola) observed during the observation period. Strong spatial change gradients occurred in relation to determining factors, such as accessibility, proximity to water, urban centres, etc., while relations to settlements where less obvious. Assessing results by country illustrated the difference in land use intensity and resource consumption between Angola and Namibia, which relate directly to historical developments, with a long period of stability in Namibia standing opposed to the recent and ongoing recovery from civil war in Angola. These are added to by statutory and traditional policy frameworks, the national endowment with natural capital (e.g. oil, uranium, diamonds, zinc) and the integration into global markets, which strongly affects national economies of both countries at large.Underlying land use decisions were found to be largely driven by individualized perspectives on growth ideologies, consumerism and wealth-aspirations connected to globalization processes. However, at present the result of these perspectives is still mainly a small-structured conversion to rainfed agriculture as a component of subsistence strategies of local livelihoods, and thus stands opposed to other regions of the world, where change processes are much more driven by large companies or follow national regulations and result in more intensive uses.  相似文献   

17.
This paper presents a methodological framework for scale-specific assessment of soil erosion by water. The framework enables the definition of hierarchical, functional and modular nested reference units which result from the integrated consideration of policy, process and model hierarchies. The framework is applied on three planning levels: at first, large scale zones are designated that show a defined risk potential for soil erosion (first level: catchments and drainage areas in the German Federal State of Saxony-Anhalt, ca. 20,000 km2). By both increasing model complexity and spatio-temporal resolution of input data, the results are locally specified within these risk zones (second level: designated farms and fields in a study area of 141 km2). This is the basis for the prediction of soil erosion areas and sediment transport to hydrologic drainage networks as well as for small scale management and measure planning (third level: designated field blocks in the study area). On this level, the mitigation of soil erosion and sediment entry to the river system is demonstrated by simulating the introduction of conservation management practices, vegetation and riparian buffer strips.  相似文献   

18.
A high level of fragmentation of farmland ownership is an important underlying cause of land degradation and, at the same time, an obstacle to sustainable land management. This study makes the first-ever analysis of long-term trends in the rate of fragmentation. Our study covers the period from the earliest stages of the current form of ownership patterns at the end of the 18th century until the present day. On the basis of significant predictors that have been identified (initial fragmentation, population growth, historical development of inheritance laws and of the land market, natural soil fertility and landscape type), we go on to project probable developments for the period from 2016 to 2045. A total of 102,984 land parcels in 56 cadastral units in the territory of Czechia have been analysed on the basis of data from four years (1785, 1840, 1950, 2015). Our study considers the development of two basic indicators of fragmentation – Mean Parcel Size and Number of Owners per 100 ha. The Mean Parcel Size has decreased over a period of 230 years from 1.08 ha to 0.64 ha, at a mean rate of −0.26% year−1. During the same period, the Number of Owners per 100 ha has risen from 17.50 to 79.66, at a mean rate of 0.61% year−1. A detailed analysis of the development trends confirms significant spatial variability and also time variability of the rates of the two indicators. The analysis also shows their mutual complementarity: growth in the rate of one of the indicators is usually accompanied by a drop in the other. The general trend that we project for the territory of Czechia in the upcoming 30 years is that there will be further diminution of the physical size of land parcels (continuing fragmentation of land parcels) accompanied by a reduction in the Number of Owners (defragmentation of land ownership).  相似文献   

19.
The impact of socio-economic changes on land use on the period 1846–2009 are studied in village of Ochotnica (105 km2) and the Jaszcze and Jamne catchments in the Polish Carpathians. The analysis of maps, aerial photos, historical and census reports indicates that during the investigated period the forest area in Ochotnica increased by 77% and in the Jaszcze and Jamne catchments by 29% and 43%, respectively and cultivated land decreased by 94% in both catchments. The population density increased from 33 to more than 50 people/km2, while employment in agriculture decreased from 98% to below 30%. The analysed period shows diverging trends of land use, referring to the three stages of socio-economic development in the Polish Carpathians. Until World War II, agricultural land contribution was the highest throughout the history of human activity. After World War II, a communist maintenance system of the land use structure was inherited from the past. A free market economy, introduced after 1989, forced the largest increase in forest area since the first colonisation of the Gorce Mountains. In contrast to the mid-mountains of Western Europe, a decrease in population density did not accompany forest expansion, nor did a dominance of small farms in the ownership system.  相似文献   

20.
Forest fragmentation is continued to be widespread in the tropics resulting in reduced ecosystem services including carbon storage. However, the effect of forest fragmentation is not considered in the current carbon policy. We investigated the effect of forest fragmentation on tree biomass carbon and soil organic carbon (SOC) storage in a moist tropical forest in Bangladesh. Above and below-ground tree biomass carbon were calculated by using widely accepted allometric equations and SOC was measured by sampling soils up to 10 cm depth and analyzing them in a soil laboratory. Results showed that carbon storage in tree biomass was significantly lower in fragmented forests (16.3 ± 1.37 t C ha−1) than in contiguous forests (31.21 ± 2.75 t C ha−1) (p < 0.001). Likewise, a significantly lower SOC was contained in the soils of fragmented forests (17.26 ± 0.83 t C ha−1) than in contiguous forests (21.62 ± 0.78 t C ha−1) (p < 0.001). Thus a total of 36% less carbon retained in tree biomass and soils in fragmented forests than in contiguous forests. Backward multiple linear regression analysis revealed tree density, tree height, tree DBH, height-diameter ratio (H/D) and tree species richness as influential factors of carbon variation in fragmented forests. All these structural parameters except tree species richness were significantly lower in fragmented forests, were positively associated with carbon storage and explained together 69% of the carbon storage variation. These findings suggest that the altered stand structure and tree allometry likely caused reduced carbon storage in fragmented forests and highlight the importance of landscape scale management intervention in the tropics. Here, we provided with the evidence of strong negative impact of forest fragmentation on carbon storage and argue that this effect should be in consideration which is currently overlooked in existing carbon accounting systems for tropical forests.  相似文献   

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