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1.
Land-use and land-cover dynamics in response to changes in climatic,biological and socio-political forces: the case of southwestern Ethiopia 总被引:26,自引:0,他引:26
Reid Robin S. Kruska Russell L. Muthui Nyawira Taye Andualem Wotton Sara Wilson Cathleen J. Mulatu Woudyalew 《Landscape Ecology》2000,15(4):339-355
Few studies of land-use/land-cover change provide an integrated assessment of the driving forces and consequences of that change, particularly in Africa. Our objectives were to determine how driving forces at different scales change over time, how these forces affect the dynamics and patterns of land use/land cover, and how land-use/land-cover change affects ecological properties at the landscape scale. To accomplish these objectives, we first developed a way to identify the causes and consequences of change at a landscape scale by integrating tools from ecology and the social sciences and then applied these methods to a case study in Ghibe Valley, southwestern Ethiopia. Maps of land-use/land-cover change were created from aerial photography and Landsat TM imagery for the period, 1957–1993. A method called `ecological time lines' was developed to elicit landscape-scale explanations for changes from long-term residents. Cropland expanded at twice the speed recently (1987–1993) than two decades ago (1957–1973), but also contracted rapidly between 1973–1987. Rapid land-use/land cover change was caused by the combined effects of drought and migration, changes in settlement and land tenure policy, and changes in the severity of the livestock disease, trypanosomosis, which is transmitted by the tsetse fly. The scale of the causes and consequences of land-use/land-cover change varied from local to sub-national (regional) to international and the links between causes and consequences crossed scales. At the landscape scale, each cause affected the location and pattern of land use/land cover differently. The contraction of cropland increased grass biomass and cover, woody plant cover, the frequency and extent of savanna burning, and the abundance of wildlife. With recent control of the tsetse fly, these ecological changes are being reversed. These complex patterns are discussed in the context of scaling issues and current conceptual models of land-use/land-cover change. 相似文献
2.
The influence of patch-delineation mismatches on multi-temporal landscape pattern analysis 总被引:3,自引:0,他引:3
Julia Linke Gregory J. McDermid Alysha D. Pape Adam J. McLane David N. Laskin Mryka Hall-Beyer Steven E. Franklin 《Landscape Ecology》2009,24(2):157-170
Investigations of land-cover change often employ metrics designed to quantify changes in landscape structure through time,
using analyses of land cover maps derived from the classification of remote sensing images from two or more time periods.
Unfortunately, the validity of these landscape pattern analyses (LPA) can be compromised by the presence of spurious change, i.e., differences between map products caused by classification error rather than real changes on the ground. To reduce
this problem, multi-temporal time series of land-cover maps can be constructed by updating (projecting forward in time) and
backdating (projecting backward in time) an existing reference map, wherein regions of change are delineated through bi-temporal
change analysis and overlaid onto the reference map. However, this procedure itself creates challenges, because sliver patches can occur in cases where the boundaries of the change regions do not exactly match the land-cover patches in the reference
map. In this paper, we describe how sliver patches can inadvertently be created through the backdating and updating of land-cover
maps, and document their impact on the magnitude and trajectory of four popular landscape metrics: number of patches (NP),
edge density (ED), mean patch size (MPS), and mean shape index (MSI). In our findings, sliver patches led to significant distortions
in both the value and temporal behaviour of metrics. In backdated maps, these distortions caused metric trajectories to appear
more conservative, suggesting lower rates of change for ED and inverse trajectories for NP, MPS and MSI. In updated maps,
slivers caused metric trajectories to appear more extreme and exaggerated, suggesting higher rates of change for all four
metrics. Our research underscores the need to eliminate sliver patches from any study dealing with multi-temporal LPA. 相似文献
3.
Amy C. Burnicki 《Landscape Ecology》2012,27(5):713-729
Researchers have emphasized the value of linking observed patterns of land-cover change to the processes driving changes in
land-use to explain the dynamics of a land change system. The association of pattern and process requires an accurate quantification
of the spatial characteristics of land-cover change. The objective of this research is to assess the impact of error on the
accuracy of landscape pattern analyses performed on maps of change. Simulation was used to develop of a series of error-free
and error-perturbed change maps, which varied with respect to the pattern of change occurring between the time-1 and time-2
land-cover maps and the patterns of error associated with the time-1 and time-2 land-cover maps. A variety of change and error
patterns were examined. The error-free and error-perturbed change maps were compared by calculating landscape pattern metrics,
which revealed the degree to which error altered the pattern of change. The introduction of error notably changed the structure
of the persistent and transitioning classes, with metrics indicating a more fragmented and variable landscape under error.
Agreement between the error-free and error-perturbed maps improved when a greater amount of change occurred within the time-series,
change was concentrated at the boundaries of land-cover classes and when time-2 errors were increasingly correlated to their
time-1 counterparts. These results have several implications for change pattern analyses given the fundamental nature of land-cover
change. 相似文献
4.
Robert H. Gardner Todd R. Lookingbill Philip A. Townsend Joseph Ferrari 《Landscape Ecology》2008,23(5):513-526
The resolution of satellite imagery must often be increased or decreased to fill data gaps or match preexisting project requirements.
It is well known that a change in resolution introduces systematic errors of size, shape, location and amount of contiguous
land cover types. Nevertheless, robust methods for rescaling landscape data are frequently required to assess patterns of
landscape change through time and over large areas. We developed a new method for rescaling spatial data that allows map resolution
(grain size) to be either increased or decreased while holding the total proportion of land cover types constant. The method
uses a weighted sampling net of variable resolution to sample an existing map and then randomly selects from the frequency
of cover types derived from this sample to assign the cover type for the corresponding location in the rescaled map. The properties
of the sampling net had a variable effect on measures of landscape pattern with the characteristic patch size (S) the most robust metric and the number of clusters (A) the most variable. A comparison of up-scaled and down-scaled maps showed that this process is not symmetrical, producing
different errors for increases versus decreases in grain size. Rescaling Landsat (30 m) imagery to the 10 m resolution of
SPOT imagery for four National Park units within Maryland and Virginia resulted in errors due to rescaling that were small
(1–2%) relative to the total error (∼11%) associated with these images. The new rescaling method is general because it provides
a single method for increasing or decreasing resolution, can be applied to maps with multiple land cover types, allows grid
geometry to be transformed (i.e., square to hexagonal grids), and provide a more consistent basis for landscape comparisons
when maps must be derived from multiple sources of classified imagery. 相似文献
5.
Uncertainties in global-scale reconstructions of historical land use: an illustration using the HYDE data set 总被引:1,自引:0,他引:1
Land use and land-use change play an important role in global integrated assessments. However, there are still many uncertainties in the role of current and historical land use in the global carbon cycle as well as in other dimensions of global environmental change. Although databases of historical land use are frequently used in integrated assessments and climate studies, they are subject to considerable uncertainties that often are ignored. This paper examines a number of the most important uncertainties related to the process of reconstructing historical land use. We discuss the origins of different types of uncertainty and the sensitivity of land-use reconstructions to these uncertainties. The results indicate that uncertainties not only arise as result of the large temporal and spatial variation in historical population data, but also relate to assumptions on the relationship between population and land use used in the reconstructions. Improving empirical data to better specify and validate the assumptions about the relationship between population and land use, while accounting for the spatial and temporal variation, could reduce uncertainties in the reconstructions. Such empirical evidence could be derived from local case studies, such as those conducted in landscape ecology, environmental history, archeology and paleoecology. 相似文献
6.
Ridding Lucy E. Newton Adrian C. Redhead John W. Watson Stephen C. L. Rowland Clare S. Bullock James M. 《Landscape Ecology》2020,35(12):2695-2712
Landscape Ecology - Historical maps of land use/land cover (LULC) enable detection of landscape changes, and help to assess drivers and potential future trajectories. However, historical maps are... 相似文献
7.
Land-cover and structural changes in a western Norwegian cultural landscape since 1865, based on an old cadastral map and a field survey 总被引:4,自引:2,他引:4
Liv Norunn Hamre Stein Tage Domaas Ingvild Austad Knut Rydgren 《Landscape Ecology》2007,22(10):1563-1574
Many studies of land-cover and structural changes in cultural landscapes have used historical maps as a source for information
about past land-cover. All transformations of historical maps onto modern coordinate systems are however burdened with difficulties
when it comes to accuracy. We show that a detailed land survey of the present landscape may enable transformation of an old
cadastral map directly onto the present terrain with very high accuracy. The detailed resulting map enabled us to locate remnants
of semi-natural grasslands and man-made structures with continuity from 1865 and to test hypotheses about relationships between
landscape changes and landscape characteristics. The main land-cover change 1865–2002 was decrease of arable fields, and addition
of three new land-cover classes: horticultural, orchard and abandoned areas. Of the 330 man-made structures present in 1865,
only 58 remained in 2002, while 63 new structures had been built after 1865. We found that semi-natural grasslands with continuity
since 1865 were situated on ground with significantly lower production capacity than mean 1865 production capacity. The man-made
structures with continuity since 1865 were also associated with areas with significantly lower production capacity than the
1865 mean, situated in significantly steeper terrain but not further from the hamlet. Our study illustrates the potential
of digitised and accurately transformed historical cadastral maps combined with detailed field surveys for analysis of land-cover
and structural changes in the cultural landscape. 相似文献
8.
Two hundred years of landscape changes were studied on a 3,760 ha area of central Corsica (France) representing a typical Mediterranean environment. Different historical sources, including an accurate land-cover map from 1774 and statistics on land cover from 1848 and 1913, were used. Three additional maps (1960, 1975 and 1990) were drawn, and a complete fire history from 1957 to 1997 was created. Forests expanded slowly by a border effect. Forest expansion was more rapid in unburnt sites (0.59% per year) than in burnt sites (0.23% per year), mostly because the initial amount of forests was greater. Because of the border effect, the combination of past landscape pattern and short distance colonization abilities of forest species may have allowed the shrublands to persist in some places after land abandonment. This persistence may explain the pattern of fire in the landscape, since shrubland burn more readily than forests. 相似文献
9.
Land cover data for landscape ecological studies are frequently obtained by field survey. In the United Kingdom, temporally separated field surveys have been used to identify the locations and magnitudes of recent changes in land cover. However, such map data contain errors which may seriously hinder the identification of land cover change and the extent and locations of rare landscape features. This paper investigates the extent of the differences between two sets of maps derived from field surveys within the Northumberland National Park in 1991 and 1992. The method used in each survey was the Phase 1 approach of the Nature Conservancy Council of Great Britain. Differences between maps were greatest for the land cover types with the smallest areas. Overall spatial correspondence between maps was found to be only 44.4%. A maximum of 14.4% of the total area surveyed was found to have undergone genuine land cover change. The remaining discrepancies, equivalent to 41.2% of the total survey area, were attributed primarily to differences of land cover interpretation between surveyors (classification error). Differences in boundary locations (positional error) were also noted, but were found to be a relatively minor source of error. The implications for the detection of land cover change and habitat mapping are discussed. 相似文献
10.
Changes in land-use/land-cover patterns in Italy and their implications for biodiversity conservation 总被引:2,自引:0,他引:2
Land-use/land-cover change is the most important factor in causing biodiversity loss. The Mediterranean region has been affected
by antropic disturbance for thousands of years, and is, nowadays, one of the most significantly altered hotspots in the world.
However, in the last years a significant increase in forest cover has been measured. These new patterns are independent from
planned conservation strategies and appear to have a substantial impact on landscapes and biodiversity. We used three land-use/land-cover
maps (from 1960 to 2000) covering the Italian peninsula to analyze the pattern of land-use/land-cover change. We measured
an increase in forests, especially in mountains, an increase in artificial areas, especially in coastal zones, and a decrease
in pastures. Intensively cultivated areas showed a limited decrease while extensively cultivated ones showed a marked decrease.
In the same period mammal and bird species followed a similar pattern, with forest birds, ungulates and carnivores increasing,
and typically Mediterranean species decreasing. We suggest that our results may provide important information, which could
be useful for conservation planning in the entire Mediterranean hotspot. We suggest that an increasing conservation effort
should be made to protect the Mediterranean-type forests and scrublands, as well as traditional agricultural practices. Moreover,
future conservation efforts should consider the broad socio-political and ecological processes that are most likely to occur
across the whole hotspot, especially along coastal areas, and the network of protected areas should be functionally integrated
in a conservation strategy that includes the human-dominated landscape. 相似文献
11.
Context
Wildfire activity in boreal forests is projected to increase dramatically in response to anthropogenic climate change. By altering the spatial arrangement of fuels, land-cover configuration may interact with climate change to influence fire-regime dynamics at landscape and regional scales.Objectives
We evaluate how land cover interacts with weather conditions to influence boreal-forest burning from 2012 to 2014 in Alaska.Methods
Using geospatial fire and land-cover data, we quantify relationships between area burned and land cover, and test whether observed patterns of burning differ from random under varying weather conditions and fire sizes.Results
Mean summer moisture index was correlated with annual area burned (ρ = ?0.78, p < 0.01), the total number of fires (ρ = ?0.68, p = 0.01), and the number of large fires (>500 km2; ρ = ?0.58, p = 0.04). Area burned was related positively to percent cover of coniferous forest and woody wetlands, and negatively to percent cover of shrub scrub, dwarf scrub, and open water and barren areas. Fires preferentially burned coniferous forest, which represented 50.1 % of the area burned in warmer/drier summers and 40.3 % of area burned in cooler/wetter summers, compared to the 34.5 % (±4.2 %) expected by random selection of land-cover classes. Overall vegetation tended to burn more similarly to random in warmer/drier than cooler/wetter years.Conclusions
Land cover exerted greater influences on boreal fire regimes when weather conditions were less favorable for forest burning. Reliable projections of boreal fire-regime change thus require consideration of the interactions between climate and land cover, as well as feedbacks from land-cover change.12.
Analysis of land-cover transitions based on 17th and 18th century cadastral maps and aerial photographs 总被引:2,自引:1,他引:1
This paper explores the possibility of using non-geometric cadastral maps from the 17th and 18th century together with aerial photographs from 1945 and 1981 to analyse land-cover change in south-east Sweden. Habitats rich in plant species in the European rural landscape seem to be correlated with a long continuity of management. Accurate spatial data from historical data sources are fundamental to understand patterns of vegetation and biodiversity in the present-day landscape. However, traditional methods for rectification of non-geometric maps using corresponding points from orthophotos or modern maps are not satisfying, as internal inaccuracies will remain in the maps. This study presents a method to rectify the maps by local warping, thereby eliminating geometrical irregularities. Further, the land-cover changes were calculated and presented as transition matrices. The extent of arable fields and grasslands were analysed in relation to soil characteristics and continuity of management. The results show a dynamic relation between grassland and arable field, albeit the overall proportions remained almost the same between 17th and 18th centuries: 60% grassland to 32% arable field. The most substantial changes in land-cover were prior to 1945. Today there is 18% grasslands left in the study area, while 56% of the land-cover is arable field. Approximately 8% of present-day land-cover is semi-natural grassland 300 years of age or more. Compared to 300 years ago there is only 1% grassland left on peat and 2% on clay. In contrast, grassland covers associated with bare bedrock have been fairly stable in size. All semi-natural grasslands with a long continuity of management were situated on shallow soils, less than 50 cm depth. The major conclusions from this study are that (i) correctly rectified, old maps are very useful to address questions of land-cover changes in historical time, (ii) general trends in land use over 300 years in this hemi-boreal landscape seem to underestimate the full dynamics of land use change, and (iii) only a small proportion of the semi-natural grassland area had a 300 year continuity of management. 相似文献
13.
Forest fragmentation as an economic indicator 总被引:13,自引:0,他引:13
Despite concern over the ecological consequences of conversion of land from natural cover to anthropogenic uses, there are few studies that show a quantitative relationship between fragmentation and economic factors. For the southside economic region of Virginia, we generated a surface (map) of urbanization pressure by interpolation of population from a ring of cities surrounding the region. The interpolated map showed a geographic gradient of urbanization pressure or demand for land that increased from northwest to southeast. Estimates of forest fragmentation were moderately correlated with the geographic gradient of urbanization pressure. The fragmentation-urbanization relationship was corroborated by examining land-cover change against the urbanization map. The geographic gradient in land-cover change was strongly correlated with the urbanization pressure gradient. The correspondence between geographic gradients in land-cover change and urbanization pressure suggests that forest fragmentation will occur at a greater rate in the eastern portion of the southside economic region in the future. 相似文献
14.
Mapping urban vegetation types is important for urban planning and assessing environmental justice. Nowadays, despite data cubes projects are providing Analysis Ready Data to facilitate time-series analysis, we did not found studies employing these data for improving urban vegetation mapping. By relying solely on open data and software, this work proposes and evaluates the integration of time-series data cubes in a hybrid image classification method to map the intra-urban space, differentiating Tree cover and Herb-shrub. The urban area of Goiânia, Goiás, Brazil, is the study area. The hybrid method combined object-based classification of a pan-sharpened CBERS-4A WPM image (spatial resolution of 2 m) with the pixel-based classification of Sentinel-2 MSI time-series data cubes (10 m). Both approaches used the Random Forest algorithm. Objects from the CBERS-4A segmentation composed the spatial unit of analysis and the class assignment depended on the Sentinel-2 time-series urban land cover probabilities. Based on both Maps probabilities, Shannon entropy was calculated to attribute the final urban land cover to the objects. Urban land cover probabilities presented similar spatial distribution patterns for both classification approaches. Regarding the thematic maps, the Herb-shrub cover area was 35% higher in Sentinel-2 time-series classification than in GEOBIA classification, but Tree cover was 21% lower. In general, 75% of the study area was equally classified by the initial approaches. However, for 9% of the remaining area, the hybrid classification improved vegetation classes accuracies by 35%, contributing to the vegetation covers identification. Thus, this study contributes to methodological procedures for urban land cover study and demonstrates that hybrid maps based on open data are effective to reduce classification mistakes, allowing more accurate monitoring, planning, and designing of different urban vegetation types. Future research efforts should focus on scale compatibility between data of different spatial resolutions and expand the use of data cubes to integrate time-series information into the GEOBIA classification. 相似文献
15.
Annick Gibon David Sheeren Claude Monteil Sylvie Ladet Gérard Balent 《Landscape Ecology》2010,25(2):267-285
Natural reforestation of European mountain landscapes raises major environmental and societal issues. With local stakeholders in the Pyrenees National Park area (France), we studied agricultural landscape colonisation by ash (Fraxinus excelsior) to enlighten its impacts on biodiversity and other landscape functions of importance for the valley socio-economics. The study comprised an integrated assessment of land-use and land-cover change (LUCC) since the 1950s, and a scenario analysis of alternative future policy. We combined knowledge and methods from landscape ecology, land change and agricultural sciences, and a set of coordinated field studies to capture interactions and feedback in the local landscape/land-use system. Our results elicited the hierarchically-nested relationships between social and ecological processes. Agricultural change played a preeminent role in the spatial and temporal patterns of LUCC. Landscape colonisation by ash at the parcel level of organisation was merely controlled by grassland management, and in fact depended on the farmer’s land management at the whole-farm level. LUCC patterns at the landscape level depended to a great extent on interactions between farm household behaviours and the spatial arrangement of landholdings within the landscape mosaic. Our results stressed the need to represent the local SES function at a fine scale to adequately capture scenarios of change in landscape functions. These findings orientated our modelling choices in the building an agent-based model for LUCC simulation (SMASH–Spatialized Multi-Agent System of landscape colonization by ASH). We discuss our method and results with reference to topical issues in interdisciplinary research into the sustainability of multifunctional landscapes. 相似文献
16.
Isaak S. Zonneveld 《Landscape Ecology》1989,3(2):67-86
The land unit, as an expression of landscape as a system, is a fundamental concept in landscape ecology. It is an ecologically homogeneous tract of land at the scale at issue. It provides a basis for studying topologic as well as chorologic landscape ecology relationships. A land unit survey aims at mapping such land units. This is done by simultaneously using characteristics of the most obvious (mappable) land attributes: land-form, soil and vegetation (including human alteration of these three). The land unit is the basis of the map legend but may be expressed via these three land attributes. The more dynamic land attributes, such as certain animal populations and water fluxes, are less suitable as diagnostic criteria, but often link units by characteristic information/energy fluxes.The land unit survey is related to a further development of the widely accepted physiographic soil survey see Edelman (1950). Important aspects include: by means of a systems approach, the various land data can be integrated more appropriately; geomorphology, vegetation and soil science support each other during all stages (photo-interpretation, field survey, data processing, final classification); the time and costs are considerably less compared with the execution of separate surveys; the result is directly suitable as a basis for land evaluation; the results can be expressed in separate soil, vegetation, land use and landform maps, or even single value maps.A land unit survey is therefore: a method for efficient survey of land attributes, such as soils, vegetation, landform, expressed in either separate or combined maps; a means of stimulating integration among separate land attribute sciences; an efficient basis for land evaluation. For multidisciplinary projects with applied ecologic aims (e.g., land management), it is therefore the most appropriate survey approach.Within the land unit approach there is considerable freedom in the way in which the various land attribute data are integrated. It is essential, however, that: during the photo-interpretation stage, the contributions of the various specialists are brought together to prepare a preliminary (land unit) photo-interpretation map; the fieldwork data are collected at exactly the same sample point, preferably by a team of specialists in which soil, vegetation and geomorphology are represented; the final map is prepared in close cooperation of all contributing disciplines, based on photo-interpretation and field data; the final map approach may vary from one fully-integrated land unit map to various monothematic maps. 相似文献
17.
Forest conservation and land development in Puerto Rico 总被引:4,自引:1,他引:3
In the Caribbean island of Puerto Rico, rapid land-use changes over the past century have included recent land-cover conversion to urban/built-up lands. Observations of this land development adjacent to reserves or replacing dense forest call into question how the changes relate to forests or reserved lands. Using existing maps, this study first summarizes island-wide land-cover change between 1977-78 and 1991-92. Then, using binomial logit modeling, it seeks evidence that simple forest cover attributes, reserve locations, or existing land cover influence land development locations. Finally, this study quantifies land development, reserve protection and forest cover by ecological zone. Results indicate that 1) pasture is more likely to undergo land development than shrubland plus forest with low canopy density, 2) forest condition and conservation status appear unimportant in that development locations neither distinguish between classes of forest canopy development nor relate to forest patch size or reserve proximity, and 3) most land development occurs in the least-protected ecological zones. Outside the boundaries of strictly protected forest and other reserves, accessibility, proximity to existing urban areas, and perhaps desirable natural settings, serve to increase land development. Over the coming century, opportunities to address ecological zone gaps in the islands forest reserve system could be lost more rapidly in lowland ecological zones, which are relatively unprotected.This revised version was published online in May 2005 with corrections to the Cover Date. 相似文献
18.
General Land Office Survey (GLOS) records from the A.D. 1840s provide data for quantitative characterization of presettlement
vegetation across western Mackinac County, Michigan, located within the mixed conifer-northern hardwoods forest region. We
analyzed data from land survey plat maps and 1958 bearing, witness, and line trees from 162 surveyed section and quarter-section
corners in order to map vegatation cover types at a level of spatial resolution appropriate for characterizing landscape heterogeneity
using standard landscape ecological metrics. As also demonstrated by a number of both classic and contemporary plant-ecological
studies, the distribution of landforms, soils properties, hydrology, and location of fire breaks all contribute to the heterogeneity
in vegetation observed at a landscape scale in the region. Through a series of spatial landscape analyses with differing grain
of resolution, in this study we determine that a grid cell size of 65 ha (0.5 mi×0.5 mi or 0.25 mi2) to 259 ha (1 mi2) gives a conservative characterization of landscape heterogeneity using standard metrics and is therefore appropriate for
use of GLOS data to study historical landscape changes. 相似文献
19.
We used an integrated modeling approach to simulate future land cover and predict the effects of future urban development
and land cover on avian diversity in the Central Puget Sound region of Washington State, USA. We parameterized and applied
a land cover change model (LCCM) that used output from a microsimulation model of urban development, UrbanSim, and biophysical
site and landscape characteristics to simulate land cover 28 years into the future. We used 1991, 1995, and 1999 Landsat TM-derived
land cover data and three different spatial partitions of our study area to develop six different estimations of the LCCM.
We validated model simulations with 2002 land cover. We combined UrbanSim land use outputs and LCCM simulations to predict
changes in avian species richness. Results indicate that landscape composition and configuration were important in explaining
land cover change as well as avian species response to landscape change. Over the next 28 years, urban land cover was predicted
to increase at the expense of agriculture and deciduous and mixed lowland forests. Land cover changes were predicted to reduce
the total number of avian species, with losses primarily in native forest specialists and gains in common synanthropic species
such as the American Crow (Corvus brachyrhynchos). The integrated modeling framework we present has potential applications in urban and natural resource planning and management
and in assessing of the effects of policies on land development, land cover, and avian biodiversity. 相似文献
20.
Land-cover change and the subsequent potential loss of natural resources due to conversion to anthropogenic use is regarded as one of the more pervasive environmental threats. Population and road data were used to generate interpolated surfaces of land demand across a large region, the mid-Atlantic states of Pennsylvania, Delaware, Maryland, Virginia, and West Virginia. The land demand surfaces were evaluated against land-cover change, as estimated using temporal decline in Normalized Difference Vegetation Index (NDVI). In general, the interpolated surfaces exhibited a plateau along the eastern seaboard that sank to a valley in the center of the study area, and then rose again to a plateau in the west that was of overall lower height than the plateau on the eastern seaboard. The spatial pattern of land-cover change showed the same general pattern as the interpolated surfaces of land demand. Correlations were significant regardless of variations used to generate the interpolated surfaces. The results suggest that human activity is the principal agent of land-cover change at regional scales in this region, and that natural resources that change as land cover changes (e.g., water, habitat) are exposed to a gradient of vulnerability that increases from west to east. 相似文献