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191.
Changes in Forest Area Along Stream Networks in an Agricultural Catchment of the Great Barrier Reef Lagoon 总被引:2,自引:1,他引:1
Scenes from the series of multispectral sensors on the Landsat satellites were used to map recent changes (between 1972 and 2004) in forest cover within and adjacent to stream networks of an intensively farmed region of the southern Great Barrier Reef catchment (Australia). Unsupervised ISODATA classifications of Tasseled-Cap transformed data (at 57 m ground resolution) mapped forest and cleared areas within 150 m of Pisoneer catchment waterways with 72.2% overall accuracy (K(hat) = 0.469), when adjusted for the size of each class. Although the user's accuracy was higher for the forest class (82.1 +/- 8.4% at alpha = 0.05), large errors of commission (34.2 +/- 8.3%) substantially affected map accuracy for the cleared class. The main reasons for misclassification include: (1) failure to discriminate narrowly vegetated riparian strips; (2) misregistration of scenes; and (3) spectral similarity of ground cover. Error matrix probabilities were used to adjust the mapped area of classes, resulting in a decline of forest cover by 12.3% and increase of clearing by 18.5% (22.4 km(2) change; 95% confidence interval: 14.3-29.6 km(2)) between 1972 and 2004. Despite the mapping errors, Landsat data were able to identify broad patterns of land cover change that were verified from aerial photography. Most of the forest losses occurred in open forest to woodland habitat dominated by Eucalyptus, Corymbia, and Lophostemon species, which were largely replaced by sugarcane cropping. Melaleuca communities were similarly affected, though they have a much smaller distribution in the catchment. 相似文献
192.
Dilini Abeygunawardane Angela Kronenburg García Zhanli Sun Daniel Müller Almeida Sitoe Patrick Meyfroidt 《Ambio》2022,51(6):1535
Actor-level data on large-scale commercial agriculture in Sub-Saharan Africa are scarce. The peculiar choice of transnational investing in African land has, therefore, been subject to conjecture. Addressing this gap, we reconstructed the underlying logics of investment location choices in a Bayesian network, using firm- and actor-level interview and spatial data from 37 transnational agriculture and forestry investments across 121 sites in Mozambique, Zambia, Tanzania, and Ethiopia. We distinguish four investment locations across gradients of resource frontiers and agglomeration economies to derive the preferred locations of different investors with varied skillsets and market reach (i.e., track record). In contrast to newcomers, investors with extensive track records are more likely to expand the land use frontier, but they are also likely to survive the high transaction costs of the pre-commercial frontier. We highlight key comparative advantages of Southern and Eastern African frontiers and map the most probable categories of investment locations.Supplementary informationThe online version contains supplementary material available at 10.1007/s13280-021-01682-z. 相似文献
193.
Healthy watersheds provide valuable services to society, including the supply and purification of fresh water. Because these natural ecosystem services lie outside the traditional domain of commercial markets, they are undervalued and underprotected. With population and development pressures leading to the rapid modification of watershed lands, valuable hydrological services are being lost, which poses risks to the quality and cost of drinking water and the reliability of water supplies. Increasing the scale and scope of programmes to protect hydrological services requires policies that harmonize land uses in watersheds with the provision of these important natural services. This article summarizes key attributes of hydrological services and their economic benefits; presents a spectrum of institutional mechanisms for safeguarding those services; discusses programmes in Quito (Ecuador), Costa Rica and New York City; and offers some lessons learned and recommendations for achieving higher levels of watershed protection. 相似文献
194.
Bambang Hero Saharjo 《Mitigation and Adaptation Strategies for Global Change》2007,12(1):135-146
Transboundary haze pollution from smoke from land preparation fires has become a perennial problem in Indonesia, especially
in the last 10 years during the dry season. Most of that smoke originates from illegal land preparation fires for oil palm
and industrial forest plantation as well as from shifting cultivation, which is usually blamed for the smoke. In order to
understand the role of fire in shifting cultivation areas dominated by peat soils, research was conducted during the dry season
of 2001 on land belonging to the community of Pelalawan village, Pelalawan district, Riau province, Indonesia. The research
showed that burning did not affect all peat areas equally. No peat was burned on a fibric site, while burning on a hemic site
varied in depth from 6.0 cm to 12.6 cm, and on a sapric site from 15.4 cm to 31.9 cm. Further, on the fibric site only phosphorus
increased significantly following burning, while on the hemic only the base saturation increased; on the sapric site, however,
both base saturation and phosphorus increased compared to the condition before burning. These data show that if fire is continues
to be used for land preparation in peat areas, peat becomes critically endangered. 相似文献
195.
D. I. Rukhovich P. V. Koroleva E. V. Vilchevskaya V. A. Romanenkov L. G. Kolesnikova 《Regional Environmental Change》2007,7(2):51-61
This paper describes the conception and construction of a geographic information system (GIS) for use in modelling changes
in soil organic carbon stocks in European Russia. A GIS of croplands for European Russia was constructed to allow the RothC
and CANDY models, and a statistical model of humus balance, to estimate how soil carbon stocks change in time. The soil map
of Russia, the database of soil properties, the map of administrative division, the land use map, the climatic grid, the map
of natural and agricultural zoning and an economic database serve as a basis for this system. A map and database of homogeneous
units, for maximum accuracy and minimum uncertainty, was created. Homogeneous characteristics are the parameters required
for modelling. In the course of this work, the sources of errors in the database and the possible ways of improving calculation
accuracy were determined and are described. The methods used and decisions taken in constructing this database are applicable
to other studies in which GIS databases need to be constructing from disparate sources. 相似文献
196.
Erik J. van Waveren 《Natural resources forum》2007,31(3):188-197
This paper examines the effects of growing land pressure on the distribution and quality of cropland allocations on customary tenured land (CTL) in Swaziland. Within the wider Sub‐Saharan context, the reform of indigenous tenure systems is now generally seen as a process of adaptation rather than replacement. The legal recognition of (existing and future) user rights is considered a practical way forward. This essentially rights‐based approach may divert attention from technical inadequacies indigenous systems may have, particularly under conditions of increasing land pressure. The case of CTL substantiates such shortcomings. CTL has seen a marked growth in population and land allocations since Independence. This had led to concerns on the land distribution efficiency in view of the improved agricultural production required to sustain the increasing number of rural households. By analysing historical changes in the number, size and quality of cropland allocations in selected rural communities, this paper demonstrates the occurrence of a high degree of inconsistency in cropland distribution at the community level, as well as inefficient land distribution at higher levels of scale. These shortcomings threaten the sustainability of the local agricultural production systems, and will need to be addressed in any meaningful reform process. 相似文献
197.
/ Geographic information systems (GIS) allow users to explore possible spatial relations that may exist within their data. At the Missouri Department of Conservation (MDC), GIS data is being used to help make management decisions. Thirteen geographic data layers of the Meramec River Basin, Missouri, were used to help demonstrate the usefulness of GIS for making fisheries management decisions. The data were used to help identify potential acquisition areas within the Meramec River Basin. The basin was separated into 22 strata based on ecoregion boundaries, watershed boundaries, and stream order. Suitability for acquisition was determined for each stratum based on species richness, habitat characteristics, percent of public land, and number of human impacts, such as gravel and ore mining. Eleven strata scored high enough to be recommended as potential acquisition areas. After further evaluation of the 11 strata, three were chosen as areas where available land and willing sellers should be considered. Four strata needed more sampling before land within them should be considered for acquisition. The final four were considered low priority because there was already a considerable amount of public land present in the strata. The analysis was helpful in allowing managers to focus in on a smaller area for acquisition consideration; 91% of the area was eliminated from the analysis. Instead of having to survey every parcel of land that becomes available, parcels that don't fall within the recommended strata can be eliminated without further investigation. 相似文献
198.
Mining of construction aggregate is often unwelcome near communities because of its disamenities or because it can destroy prime farmland and displace other desirable land uses. Such conflicts have led to prohibitions against mining near cities or on high-value farmland, causing these operations to be relocated to more distant locations. The cost of this relocation may go unnoticed if they are indirect, diffused and rise gradually over time, but they may be significant due to the high transportation cost of moving these materials long distances. 相似文献
199.
200.
Conserving genetic diversity requires an assessment of the distribution of genetic variants in relation to patterns of land
use and environmental variation at a regional scale. This assessment requires a novel approach to integrating and analyzing
the genetic and environmental data across spatial scales. To explore the integration of genetic data with other geospatial
data sets, we developed a GIS-based approach for examining patterns of genetic diversity for several species of salamanders
in southern Appalachians. The genetic data, from allozyme surveys in the genetics literature, were integrated into a GIS database
along with related attributes including population identifications and spatial locations. Using existing geospatial data,
we classified sample locations as being either protected from anthropogenic disturbance (e.g., National Parks, Wilderness
Areas) or as unprotected (e.g., private lands, multiple-use lands in National Forests). We used multidimensional scaling of
allelic frequencies and contributions of populations to interpopulation differences in allelic richness to determine which
populations had genetic characteristics most different from other populations in the sample. Measures of genetic differentiation
were integrated into the GIS database to facilitate spatial analysis and visualization of the indices in relation to land
use. This approach was useful for both identification of populations with components of genetic variation that were not well
represented at protected sites and for identifying areas of species distributions where more genetic sampling would be necessary
to make informed management decisions. Our approach could be readily adapted for use by managers and geneticists working with
other species and types of genetic markers. 相似文献