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1.
The West Nile virus (WNV) may post a significant health risk for mammals, including humans and insects. This study examines the spatial–temporal effects of environmental factors on WNV dissemination with a case study of ten counties in the southern California, where the epidemic was recently most prevalent within the USA. WNV surveillance data were obtained from the California Vectorborne Disease Surveillance System and Centers for Disease Control and Prevention. Remote sensing and Geographic Information Systems (GIS) techniques were combined to derive environmental variables. Principal component analysis was performed to select the most relevant environmental variables. Two ecological zones were identified based on the selected variables. Identification of risk areas for WNV was limited to a zone with 95% mosquitoes surveillance records. Three time windows, the epidemiological weeks?18–26, 27–35, and 36–44 in each year of 2007–2009, were examined in details with risk area mapping. It is found that the southern part of San Joaquin Valley in Kern County and Los Angeles County (especially its southern part) were the most vulnerable locations for WNV outbreak. Main factors contributing to the WNV propagation included summer mean temperature, annual mean deviation from the mean temperature, land surface temperature, elevation, landscape complexity, landscape diversity, and vegetation water content. The result of this study improves understanding of WNV ecology and provides tools for detecting, tracking, and predicting the epidemic. The holistic approach developed for this study, which integrated remotely sensed, GIS-based, and in situ-measured environmental data with landscape metrics, may be applied to studies of other vector-borne diseases.  相似文献   

2.
Socioeconomic forces are not only among the main drivers of landscape dynamics; they are also influenced by landscape patterns. Landscape structure and functions are closely related to natural and social factors. The objective of this study was to investigate the relationships among some human-related factors and landscape ecological metrics as landscape pattern indicators and to identify suitable metrics for modeling these relationships. To this goal, landscape ecological metrics were calculated for each of the 32 counties of Mazandaran and Guilan provinces located in the southern basin of the Caspian Sea using land use/cover maps in class level. Stream network metrics were calculated using a digital elevation model, road density metrics were calculated using map of main roads separately, and significant metrics were selected according to results of correlation tests and factor analysis. The correlations between these metrics and socioeconomic factors were tested, and their relationships were modeled with multiple linear regressions. Significant relationships were found among socioeconomic factors and landscape ecological metrics, and land use/cover data are applicable for modeling socioeconomic factors, especially demographic and employment structure factors. Among the landscape metrics applied in this study, road density, mean patch size, mean nearest neighbor distance, and percentage of a land use/cover class in landscape were important metrics for predicting socioeconomic factors. Our findings indicated that road density metric and percentages of urban class are useful for predicting urban socioeconomic factors and percentage of agriculture and forest classes in the landscape are suitable metrics for predicting rural socioeconomic factors.  相似文献   

3.
This paper intended to examine the seasonal variations in the relationship between landscape pattern and land surface temperature based on a case study of Indianapolis, United States. The integration of remote sensing, GIS, and landscape ecology methods was used in this study. Four Terra's ASTER images were used to derive the landscape patterns and land surface temperatures (LST) in four seasons in the study area. The spatial and ecological characteristics of landscape patterns and LSTs were examined by the use of landscape metrics. The impact of each land use and land cover type on LST was analyzed based on the measurements of landscape metrics. The results show that the landscape and LST patterns in the winter were unique. The rest of three seasons apparently had more agreeable landscape and LST patterns. The spatial configuration of each LST zone conformed to that of each land use and land cover type with more than 50% of overlap in area for all seasons. This paper may provide useful information for urban planers and environmental managers for assessing and monitoring urban thermal environments as result of urbanization.  相似文献   

4.
A majority of the research on forest fragmentation is primarily focused on animal groups rather than on tree communities because of the complex structural and functional behavior of the latter. In this study, we show that forest fragmentation provokes surprisingly rapid and profound alterations in tropical tree community. We examine forest fragments in the tropical region using high-resolution satellite imagery taken between 1973 and 2004 in the Southern Western Ghats (India) in relation to landscape patterns and phytosociological datasets. We have distinguished fragmentation in six categories—interior, perforated, edge, transitional, patch, and undetermined—around each forested pixel. Furthermore, we have characterized each of the fragment class in the evergreen and semi-evergreen forest in terms of its species composition and richness, its species similarity and abundance, and its regeneration status. Different landscape metrics have been used to infer patterns of land-use changes. Contiguous patches of >1,000 ha covered 90% of evergreen forest in 1973 with less porosity and minimal plantation and anthropogenic pressures; whereas in 2004, the area had 67% forest coverage and a high level of porosity, possibly due to Ochlandra spread and increased plantations which resulted in the loss of such contiguous patches. Results highlight the importance of landscape metrics in monitoring land-cover change over time. Our main conclusion was to develop an approach, which combines information regarding land cover, degree of fragmentation, and phytosociological inputs, to conserve and prioritize tropical ecosystems.  相似文献   

5.
This article investigates the relationship of local air pollution pattern with urban land use and with urban thermal landscape using a GIS approach. Ambient air quality measurements for sulfur dioxide, nitrogen oxide, carbon monoxide, total suspended particles, and dust level were obtained for Guangzhou City in South China between 1981 and 2000. Landsat TM images and aerial photo derived maps were used to examine city's land use and land cover at different times and changes. Landsat thermal infrared data were employed to compute land surface temperatures and to assess urban thermal patterns. Relationships among the spatial patterns of air pollution, land use, and thermal landscape were sought through GIS and correlation analyses. Results show that the spatial patterns of air pollutants probed were positively correlated with urban built-up density, and with satellite derived land surface temperature values, particularly with measurements taken during the summer. It is suggested that further studies investigate the mechanisms of this linkage, and that remote sensing of air pollution delves into how the energy interacts with the atmosphere and the environment and how sensors see pollutants. Thermal infrared imagery could play a unique role in monitoring and modeling atmospheric pollution.  相似文献   

6.
Enterococci bacteria are used to indicate the presence of human and/or animal fecal materials in surface water. In addition to human influences on the quality of surface water, a cattle grazing is a widespread and persistent ecological stressor in the Western United States. Cattle may affect surface water quality directly by depositing nutrients and bacteria, and indirectly by damaging stream banks or removing vegetation cover, which may lead to increased sediment loads. This study used the State of Oregon surface water data to determine the likelihood of animal pathogen presence using enterococci and analyzed the spatial distribution and relationship of biotic (enterococci) and abiotic (nitrogen and phosphorous) surface water constituents to landscape metrics and others (e.g. human use, percent riparian cover, natural covers, grazing, etc.). We used a grazing potential index (GPI) based on proximity to water, land ownership and forage availability. Mean and variability of GPI, forage availability, stream density and length, and landscape metrics were related to enterococci and many forms of nitrogen and phosphorous in standard and logistic regression models. The GPI did not have a significant role in the models, but forage related variables had significant contribution. Urban land use within stream reach was the main driving factor when exceeding the threshold (> or =35 cfu/100 ml), agriculture was the driving force in elevating enterococci in sites where enterococci concentration was <35 cfu/100 ml. Landscape metrics related to amount of agriculture, wetlands and urban all contributed to increasing nutrients in surface water but at different scales. The probability of having sites with concentrations of enterococci above the threshold was much lower in areas of natural land cover and much higher in areas with higher urban land use within 60 m of stream. A 1% increase in natural land cover was associated with a 12% decrease in the predicted odds of having a site exceeding the threshold. Opposite to natural land cover, a one unit change in each of manmade barren and urban land use led to an increase of the likelihood of exceeding the threshold by 73%, and 11%, respectively. Change in urban land use had a higher influence on the likelihood of a site exceeding the threshold than that of natural land cover.  相似文献   

7.
The rate and intensity of land use land cover (LULC) change has increased considerably during the past couple of decades. Mining brings significant alterations in LULC specifically due to its impact on forests. Parts of Central India are well endowed with both forests and minerals. Here, the conflict between human interests and nature has intensified over time. Monitoring and assessment of such conflicts are important for land management and policy making. Remote sensing and Geographical Information System have the potential to serve as accurate tools for environmental monitoring. Understanding the importance of landscape metrics in land use planning is challenging but important. These metrics calculated at landscape, class, and patch level provide an insight into changing spatiotemporal distribution of LULC and ecological connectedness. In the present study, geospatial tools in conjunction with landscape metrics have been used to assess the impact of coal mining on habitat diversity. LULC maps, change detection analysis, and landscape metrics have been computed for the four time periods (1972, 1992, 2001, and 2006). There has been a significant decline in forest cover especially of the Sal-mixed forests, both in area as well as quality, due to flouted mining regulations. Reclamation of mined lands has also been observed in some of the areas since 2001.  相似文献   

8.
Landscape monitoring usually relies on land-use statistics whichreflect the share of land-sue/land cover types. In order tounderstand the functioning of landscapes, landscape pattern mustbe considered as well. Indicators which address the spatialconfiguration of landscapes are therefore needed. Thesuitability of landscape metrics, which are computed from thetype, geometry and arrangement of patches, is examined. Two casestudies in a surface mining region show that landscape metricscapture landscape structure but are highly dependent on the datamodel and on the methods of data analysis. For landscape metricsto become part of policy-relevant sets of environmentalindicators, standardised procedures for their computation fromremote sensing images must be developed.  相似文献   

9.
The concept of ecosystem conservation as a broad theme came into existence during the 1970s under the Man and Biosphere Programme (MAB) of the United Nations Educational, Scientific and Cultural Organization (UNESCO). The Indian Government followed this approach and chose the method to segregate the landscape for conservation of the ecosystem as well as for the development of the local economy and its people. We have examined the effect of this policy and concurrently developed a theoretical modeling approach to understand how human behavior is changing under shifting political, socioeconomic and environmental conditions. A specific focus has been on how the landscape is changing in the mountains of the Indian Himalayan region where about 10% of the total geographical area is converted into protected landscape for conservation of biodiversity. For local people living in the Himalayan mountains in India, agriculture is the main land use activity and is strongly linked to the forests in providing sustainability. There are several branches in the rural ecosystems where the local people's economy was centered. These include agriculture, animal husbandry, medicinal and aromatic plants cultivation, forest resource collection, tourism and other occupations. The greatest proportion of the population was engaged in the agriculture sector, whose contribution is high in the rural economy (61%); followed by animal husbandry (19%), forest resource collection for economic gain (18%), and medicinal and aromatic plants cultivation (1.5%). However, three decades ago the animal husbandry branch of the rural ecosystem was contributing the maximum share towards rural household income (40%) followed by tourism (35.2%), and lastly agriculture (14%). The desire of farmers to secure the optimum output from agricultural land use has resulted in an increase for resource collection from the forests. The people's perception (n = 1,648) regarding overall changes occurring in the region was varied and most showed that the current trend within rural ecosystems has emerged because of the implementation of conservation policies/creation of national park and biosphere reserve (80%), followed by limitation (22%), climate (20%), population growth (7%), national economy (10%) and least by socioeconomic change (5%). The theoretical agent model developed here draws attention to agent/farmer behavior and land resource use for his livelihood in the temporal dimension. The current study would be helpful to introduce new approaches for the development of the methodological and theoretical aspects associated with the complex human and ecosystem interactions in the Himalayan mountains for sustainable landscape development.  相似文献   

10.
An interesting alternative to wall-to-wall mapping approaches for the estimation of landscape metrics is to use sampling. Sample-based approaches are cost-efficient, and measurement errors can be reduced considerably. The previous efforts of sample-based estimation of landscape metrics have mainly been focused on data collection methods, but in this study, we consider two estimation procedures. First, landscape metrics of interest are calculated separately for each sampled image and then the image values are averaged to obtain an estimate of the entire landscape (separated procedure, SP). Second, metric components are calculated in all sampled images and then the aggregated values are inserted into the landscape metric formulas (aggregated procedure, AP). The national land cover map (NLCM) of Sweden, reflecting the status of land cover in the year 2000, was used to provide population information to investigate the statistical performance of the estimation procedures. For this purpose, sampling simulation with a large number of replications was used. For all three landscape metrics, the second procedure (AP) produced a lower relative RMSE and bias than the first one (SP). A smaller sample unit size (50 ha) produced larger bias than a larger one (100 ha), whereas a smaller sample unit size produced a lower variance than a larger sample unit. The efficiency of a metric estimator is highly related to the degree of landscape fragmentation and the selected procedure. Incorporating information from all of the sampled images into a single one (aggregated procedure, AP) is one way to improve the statistical performance of estimators.  相似文献   

11.
This study investigates land cover change near the abandoned Pine Point Mine in Canada’s Northwest Territories. Industrial mineral development transforms local environments, and the effects of such disturbances are often long-lasting, particularly in subarctic, boreal environments where vegetation conversion can take decades. Located in the Boreal Plains Ecozone, the Pine Point Mine was an extensive open pit operation that underwent little reclamation when it shut down in 1988. We apply remote sensing and landscape ecology methods to quantify land cover change in the 20 years following the mine’s closure. Using a time series of near-anniversary Landsat images, we performed a supervised classification to differentiate seven land cover classes. We used raster algebra and landscape metrics to track changes in land cover composition and configuration in the 20 years since the mine shut down. We compared our results with a site in Wood Buffalo National Park that was never subjected to extensive anthropogenic disturbance. This space-for-time substitution provided an analog for how the ecosystem in the Pine Point region might have developed in the absence of industrial mineral development. We found that the dense conifer class was dominant in the park and exhibited larger and more contiguous patches than at the mine site. Bare land at the mine site showed little conversion through time. While the combination of raster algebra and landscape metrics allowed us to track broad changes in land cover composition and configuration, improved access to affordable, high-resolution imagery is necessary to effectively monitor land cover dynamics at abandoned mines.  相似文献   

12.
How to assess the potential habitat integrating landscape dynamics and population research, and how to reintroduce animals to potential habitats in environments highly human disturbed are still questions to be answered in conservation biology. According to behavioral research on Elaphurus davidians, we have developed a suitability index and a risk index to evaluate the potential habitats for the deer. With these indices, we conducted two transect assessments to evaluate the gradient change of the target region. Then, taking rivers as border lines, we tabulated the forest areas, high grassland area and total area and then compared the forest and high grassland area in each subregion. Furthermore, we computed the land use transfer matrix for the whole Yancheng coast during 1987-2000. We also computed human modified index (HMI) in six subregions. Lastly with a geographical information system support we obtained the spatial distribution of the indices and evaluation of the whole potential habitats from a neighborhood analysis. The transect assessment showed that the suitability of the coastal area was higher than that of the inland area for the deer, while the southern area was higher than the northern. Landscape metrics and HMI analysis showed that different landscape patterns and different anthropogenic disturbance existed within the region, and the increasing human disturbance was the key factor causing the pattern dynamics. The evaluation of potential habitats showed that there was an estimated carrying capacity of no more than 10,000 for David's deer reintroduction into the natural area. Also the reintroduction strategy was discussed. This integrated approach linked the population research and the landscape metrics, and the dataset with different scale; thus, it is an approach likely to be useful for the protection of other large animal in a landscape highly disturbed by humans.  相似文献   

13.
As an important component of sustainable development in mountain areas, evaluation for sustainable land use is always one of the hotpots of researches on sustainable development. Traditional evaluation for sustainable land use mainly focuses on the sustainability of land use model and biological production on temporal scale, and overlooks the effects of land use patterns on the sustainability, while landscape ecology can be a good help to realize the spatial analysis of sustainable land use. In this study, a synthetic evaluation indexes system for sustainable land use was constructed through the application of landscape metrics. Taking Yongsheng County of Yunnan Province, China as a case study, a series of quantitative evaluation were conducted in 1996, 1999 and 2001, to monitor the temporal dynamics of regional land use sustainability. Two indicators, contributing amount of indexes, and obstacle amount of indexes, were also set up to ascertain the significance of all the evaluation indexes to the evaluation results. The results showed that, in the study phases, the land use sustainability of the whole county had been low with a stable but great spatial difference, and great changes took place in regional land use system in 1999 with the deviation from the aim of sustainable land use. It also showed that, the most important indexes contributing for the land use sustainability in the study period, were the indexes of population density and land use degree, followed by the index of landscape diversity and cropping index. And the most important indexes counteracting the land use sustainability were the indexes of per unit area total production value of industry and agriculture, per unit area yield of cereal crops, landscape fragmentation, followed by the indexes of per unit area yield of economic crops and fertilizer consume per unit area.  相似文献   

14.
This study was aimed at analyzing and interpreting changes in landscape pattern and connectivity in the Urla district, Turkey using core landscape metrics based on a 42-year data derived from 1963 CORONA and 2005 ASTER satellite images and ten 1/25,000 topographical maps (1963–2005). The district represents a distinctive example of re-emerged suburbanization in the Izmir metropolitan area. In order to explore landscape characteristics of the study area, nine landscape composition and configuration metrics were chosen as follows: class area, percentage of landscape, number of patches, patch density, largest patch index, landscape shape index, mean patch size, perimeter area fractal dimension, and connectance index. The landscape configurations in the Urla district changed significantly by 2005 in that the process of (sub-)urbanization in the study area evolved from a rural, monocentric urban typology to a more suburban, polycentric morphology. Agricultural, maquis-phrygana, and forest areas decreased, while the built-up, olive plantation and phrygana areas increased. There was nearly a fivefold increase in the built-up areas during the study period, and the connectivity of the natural landscape declined. To prevent further fragmentation, it is important to keep the existing natural land cover types and agricultural areas intact. More importantly, a sustainable development scenario is required that contains a green infrastructure, or an ecological network planning for conservation and rehabilitation of the vital natural resources in the study area.  相似文献   

15.
The relationship between benthic macroinvertebrate assemblages and cattle density was assessed from fall 2002 through spring 2004 in five small streams that represented a gradient of cattle grazing intensity. All study stream reaches were in pasture with no woody riparian vegetation, but varied in the intensity of cattle grazing (0 cattle ha−1 at site 1 to 2.85 cattle ha−1 at site 5). Regression analysis indicated highly significant and strong macroinvertebrate metric responses to cattle density during most sampling periods. The majority of metrics responded negatively to increased grazing, while a few (total taxa richness, number of sensitive taxa, and % collector filterers) increased along the gradient before declining at the most heavily grazed sites. Total number of sensitive taxa and % Coleoptera had the strongest relationship with cattle density throughout the study period. During some sampling periods, nearly 80% of the variation in these metrics was explained by cattle density. The elmid beetle, Oulimnius, had a particularly strong negative response to the grazing gradient. Study site groupings based on taxa composition, using detrended correspondence analysis (DCA), indicated that benthic samples collected from the reference site and light rotational grazing site were more similar in macroinvertebrate taxa composition than samples collected from the intermediate grazing and heavy grazing sites. Our findings demonstrate that biological integrity, as measured by benthic macroinvertebrate metrics and assemblage composition, is highly related to cattle density in small streams in the Blue Ridge mountains, Virginia, USA. This suggests that the degree of agricultural intensity should be given consideration in stream assessments, as well as land use planning and regulatory decisions.  相似文献   

16.
RecentAbstract. Recent approaches to wetland assessment have advocated a multilevel approach which incorporates assessments based on landscape (remote sensing) data, on-site but “rapid” methods, and intensive methods where quantitative data is collected. Brown and Vivas (2004) recently pro- posed an assessment method that uses remote sensing information (Landscape Development Index or LDI) and propose that it may also be usable as a quantified human disturbance gradient. The LDI was evaluated using a large reference wetland data set from Ohio using land use percentages within a 1 km radius circle of the wetlands. The LDI had interpretable and significant relationships with another human disturbance gradient (the Ohio Rapid Assessment Method for Wetlands or ORAM) and with most metrics and scores from the Vegetation Index of Biotic Integrity (VIBI) developed for use in the State of Ohio. Metrics from emergent wetlands had the most significant correlations with the LDI (10 of 10 metrics), followed by forested wetlands (8 of 10 metrics) and shrub wetlands (4 of 10). Poor correlation for VIBI scores and metrics of shrub wetlands was due to differences in attainable LDI scores based on ecoregion and natural buffers shielding the wetland from otherwise intensive land uses. The ORAM and VIBI were developed for use in wetlands in Ohio completely independent of the LDI. It is an important test of the LDI concept that so many interpretable and significant relationships occurred between the VIBI scores, VIBI metric values, and the ORAM scores. For the purposes of VIBI development, the LDI is an independent, quantified disturbance gradient that has provided an additional test of the VIBI. Given its theoretical underpinnings and the fact that it uses quantified land use percentages, the LDI has many advantages over more qualita- tive human disturbance gradients. Using land use percentages from increasingly smaller distances from the wetland edge (100-200 m) may improve the resolution of the LDI to detect on-site dis-turbances to a wetland which degrade its ecological condition. The LDI should be evaluated with other large reference data sets in other regions to evaluate its validity and usefulness as an assessment tool.  相似文献   

17.
The availability of Landsat data allows improving the monitoring and assessment of large-scale areas with land cover changes in rapid developing regions. Thus, we pretend to show a combined methodology to assess land cover changes (LCCs) in the Hamoun Wetland region (Iran) over a period of 30-year (1987–2016) and to quantify seasonal and decadal landscape and land use variabilities. Using the pixel-based change detection (PBCD) and the post-classification comparison (PCC), four land cover classes were compared among spring, summer, and fall seasons. Our findings showed for the water class a higher correlation between spring and summer (R2?=?0.94) than fall and spring (R2?=?0.58) seasons. Before 2000, ~?50% of the total area was covered by bare soil and 40% by water. However, after 2000, more than 70% of wetland was transformed into bare soils. The results of the long-term monitoring period showed that fall season was the most representative time to show the inter-annual variability of LCCs monitoring and the least affected by seasonal-scale climatic variations. In the Hamoun Wetland region, land cover was highly controlled by changes in surface water, which in turn responded to both climatic and anthropogenic impacts. We were able to divide the water budget monitoring into three different ecological regimes: (1) a period of high water level, which sustained healthy extensive plant life, and approximately 40% of the total surface water was retained until the end of the hydrological year; (2) a period of drought during high evaporation rates was observed, and a mean wetland surface of about 85% was characterized by bare land; and (3) a recovery period in which water levels were overall rising, but they are not maintained from year to year. After a spring flood, in 2006 and 2013, grassland reached the highest extensions, covering till more than 20% of the region, and the dynamics of the ecosystem were affected by the differences in moisture. The Hamoun wetland region served as an important example and demonstration of the feedbacks between land cover and land uses, particularly as pertaining to water resources available to a rapidly expanding population.  相似文献   

18.
Photovoltaic plants developed on rural land are becoming a common infrastructure in the Mediterranean region and may contribute, at least indirectly, to various forms of environmental degradation including landscape deterioration, land take, soil degradation and loss in traditional cropland and biodiversity. Our study illustrates a procedure estimating (i) the extension of ground-mounted photovoltaic fields at the municipal scale in Italy and (ii) inferring the socioeconomic profile of the Italian municipalities experiencing different expansion rates of ground-mounted photovoltaic fields over the last years (2007-2014). The procedure was based on diachronic information derived from official data sources integrated into a geographical decision support system. Our results indicate that the surface area of ground-mounted photovoltaic fields into rural land grew continuously in Italy between 2007 and 2014 with positive and increasing growth rates observed during 2007-2011 and positive but slightly decreasing growth rates over 2012-2014, as a result of market saturation and policies containing the diffusion of solar plants on greenfields. We found important differences in the density of ground-mounted solar plants between northern and southern Italian municipalities. We identified accessible rural municipalities in southern Italy with intermediate population density and large availability of non-urban land as the most exposed to the diffusion of solar plants on greenfields in the last decade. Our approach is a promising tool to estimate changes in the use of land driven by the expansion of photovoltaic fields into rural land.  相似文献   

19.
Incident electromagnetic radiation hitting the Earth’s surface shows three phenomena as absorptivity, reflectivity and transmissivity where sum of the three is equal to one. The transmissivity is zero when the surface is opaque. There is a strong relationship between absorptivity and emissivity that is explained by Kirchhoff’s Law. Emissivity is managed by the thermal radiation on the Earth’s surface. Thermal radiation related with the heat transfer of the electromagnetic radiation is controlled by passing energy of atoms and molecules. There are different sources of energy other than the Sun such as geothermal activities, volcanoes and manufacturing plants that contributes to the emissivity of the surface. The thermal radiation produced by manufacturing plants contributes to the Earth’s surface temperature as well.In this study, land surface temperatures were estimated by using inverse Planck function from five Advanced Spaceborne Thermal Emission and Reflection Radiometer remote-sensing satellite sensor thermal infrared bands. It is aimed to highlight hotspots related to manufacturing plants in the region of Kocaeli, Turkey. The hotspots are examined statistically with the minimum noise fraction, the independent component analysis, the local Moran’s I index and the Getis-Ord Gi index methods by using land surface temperatures.  相似文献   

20.
We studied landscape dynamics for three time periods (<1950, 1965, and 1997) along a gradient of agricultural intensity from highly intensive agriculture to forested areas in southern Québec. Air photos were analyzed to obtain long-term information on land cover (crop and habitat types) and linear habitats (hedgerows and riparian habitats) and landscape metrics were calculated to quantify changes in habitat configuration. Anthropogenic areas increased in all types of landscapes but mostly occurred in the highly disturbed cash crop dominated landscape. Perennial crops (pasture and hayfields) were largely converted into annual crops (corn and soybean) between 1965 and 1997. The coalescence of annual crop fields resulted in a more homogeneous agricultural landscape. Old fields and forest cover was consistently low and forest fragmentation remained stable through time in the intensive agriculture landscapes. However, forest cover increased and forest fragmentation receded in the forest-dominated landscapes following farm abandonment and the transition of old fields into forests. Tree-dominated hedgerows and riparian habitats increased in areas with intensive agriculture. Observed changes in land cover classes are related to proximate factors, such as surficial deposits and topography. Agriculture intensification occurred in areas highly suitable for agriculture whereas farm abandonment was observed in poor-quality agriculture terrains. Large-scale conversion of perennial crops into annual crops along with continued urbanization exerts strong pressures on residual natural habitats and their inhabiting wildlife. The afforestation process occurring in the more forested landscapes along with the addition of tree-dominated hedgerows and riparian habitats in the agriculture-dominated landscapes should improve landscape ecological value.  相似文献   

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