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1.
Selection of scale for Everglades landscape models 总被引：3，自引：0，他引：3
This article addresses the problem of determining the optimal “Model Grain” or spatial resolution (scale) for landscape modeling
in the Everglades. Selecting an appropriate scale for landscape modeling is a critical task that is necessary before using
spatial data for model development. How the landscape is viewed in a simulation model is dependent on the scale (cell size)
in which it is created. Given that different processes usually have different rates of fluctuations (frequencies), the question
of selection of an appropriate modeling scale is a difficult one and most relevant to developing spatial ecosystem models.
The question of choosing the appropriate scale for modeling is addressed using the landscape indices (e.g., cover fraction, diversity index, fractal dimension, and transition probabilities) recently developed for quantifying overall
characteristics of spatial patterns. A vegetation map of an Everglades impoundment area developed from SPOT satellite data
was used in the analyses. The data from this original 20 × 20 m data set was spatially aggregated to a 40 × 40 m resolution
and incremented by 40 meters on up to 1000 × 1000 m (i.e., 40, 80, 120, 160 … 1000) scale. The primary focus was on the loss of information and the variation of spatial indices as
a function of broadening “Model Grain” or scale.
Cover fraction and diversity indices with broadening scale indicate important features, such as tree islands and brush mixture
communities in the landscape, nearly disappear at or beyond the 700 m scale. The fractal analyses indicate that the area perimeter
relationship changes quite rapidly after about 100 m scale. These results and others reported in the paper should be useful
for setting appropriate objectives and expectations for Everglades landscape models built to varying spatial scales. 相似文献
2.
We need an integrated assessment of the bioenergy production at landscape scale for at least three main reasons: (1) it is predictable that we will soon have landscapes dedicated to bioenergy productions; (2) a number of “win–win” solutions combining several dedicated energy crops have been suggested for a better use of local climate, soil mosaic and production systems and (3) “well-to-wheels” analyses for the entire bioenergy production chain urge us to optimize the life cycle of bioenergies at large scales. In this context, we argue that the new generation of landscape models allows in silico experiments to estimate bioenergy distributions (in space and time) that are helpful for this integrated assessment of the bioenergy production. The main objective of this paper was to develop a detailed modeling methodology for this purpose. We aimed at illustrating and discussing the use of mechanistic models and their possible association to simulate future distributions of fuel biomass. We applied two separated landscape models dedicated to human-driven agricultural and climate-driven forested neighboring patches. These models were combined in the same theoretical (i.e. virtual) landscape for present as well as future scenarios by associating realistic agricultural production scenarios and B2-IPCC climate scenarios depending on the bioenergy type (crop or forest) concerned in each landscape patch. We then estimated esthetical impacts of our simulations by using 3D visualizations and a quantitative “depth” index to rank them. Results first showed that the transport cost at landscape scale was not correlated to the total biomass production, mainly due to landscape configuration constraints. Secondly, averaged index values of the four simulations were conditioned by agricultural practices, while temporal trends were conditioned by gradual climate changes. Thirdly, the most realistic simulated landscape combining intensive agricultural practices and climate change with atmospheric CO2 concentration increase corresponded to the lowest and unwanted bioenergy conversion inefficiency (the biomass production ratio over 100 years divided by the averaged transport cost) and to the most open landscape. Managing land use and land cover changes at landscape scale is probably one of the most powerful ways to mitigate negative (or magnify positive) effects of climate and human decisions on overall biomass productions. 相似文献
3.
Ecologists have long recognized the importance of spatial and temporal patterns that characterize heterogeneity in landscapes. However, despite the realization that inferences about ecological phenomena are scale dependent, little attention has been paid to determining appropriate scales of measurement (e.g., plot or grain size) in studies of landscape dynamics or ecosystem change. This paper compares the results from three data sets using several quantitative methods available for characterizing landscape heterogeneity and/or for determining scale of measurement. Methods evaluated include tests of non-randomness, estimation of patch size, spectral analysis, fractals, variance ratio analysis, and correlation analysis. The results showed that no one method provides consistently good estimates of scale. Thus, sampling strategies for landscape studies should be derived from estimates of patch size and/or scale of pattern obtained from more than one of these methods. 相似文献
4.
5.
Determination of ecological scale 总被引：4，自引：0，他引：4
David W. Carlile John R. Skalski John E. Batker John M. Thomas V. I. Cullinan 《Landscape Ecology》1989,2(4):203-213
We suggest that ecological processes and physical characteristics possess an inherent scale at which the processes or characteristics occur over the landscape. We propose a conceptual spatial response model that describes the nature of this ecological scale. Based on the proposed spatial model, we suggest methods for estimating the size of study plots or transects and the distance between replicate plots needed to approach statistical independence. Using data on percent cover for Agropyron spicatum, a common arid-land bunchgrass, we demonstrated four relationships that should hold if the spatial response model is appropriate. These relationships are sample variance increases as functions of (1) transect segment length and (2) intersegment length (transect segment dispersal), and correlation decreases as functions of (3) intersegment length and (4) transect segment length. Based on evaluation of these four relationships, cover for A. spicatum is correlated over the landscape on a scale of 400 to 700 m, and a segment length of 64 to 128 m is most appropriate for measuring cover for this species. 相似文献
6.
Species distribution models (SDMs) often use elevation as a surrogate for temperature or utilise elevation sensitive interpolations
from weather stations. These methods may be unsuitable at the landscape scale, especially where there are sparse weather stations,
dramatic variations in exposure or low elevational ranges. The goal of this study was to determine whether radiation, moisture
or a novel estimate of exposure could improve temperature estimates and SDMs for vegetation on the Illawarra Escarpment, near
Sydney, Australia. Forty temperature sensors were placed on the soil surface of an approximately 12,000 ha study site between
November 2004 and August 2006. Linear regression was used to determine the relationship with environmental factors. Elevation
was correlated more with moderate temperatures (winter maximums, summer minimums, spring and autumn averages) than extreme
temperatures (summer maximums, winter minimums). The correlation (r
2) between temperature and environmental factors was improved by up to 0.38 by incorporating exposure, moisture and radiation
in the regressions. Summer maximums and winter minimums were predominately determined by exposure to the NW and coastal influences
respectively, while exposure to the NE and SW was important during other seasons. These directions correspond with the winds
that are most influential in the study area. The improved temperature estimates were used in Generalised Additive Models for
37 plant species. The deviance explained by most models was increased relative to elevation, especially for moist rainforest
species. It was concluded that improving the accuracy of seasonal temperature estimates could improve our ability to explain
the patchy distribution of many species.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
7.
Impact of scale on morphological spatial pattern of forest 总被引：1，自引：1，他引：0
Katarzyna Ostapowicz Peter Vogt Kurt H. Riitters Jacek Kozak Christine Estreguil 《Landscape Ecology》2008,23(9):1107-1117
Assessing and monitoring landscape pattern structure from multi-scale land-cover maps can utilize morphological spatial pattern
analysis (MSPA), only if various influences of scale are known and taken into account. This paper lays part of the foundation
for applying MSPA analysis in landscape monitoring by quantifying scale effects on six classes of spatial patterns called:
core, edge, perforation, branch, connector and islet. Four forest maps were selected with different forest composition and configuration. The sensitivity of MSPA to scale was
studied by comparing frequencies of pattern classes in total forest area for various combinations of pixel size (P) and size
parameter (S). It was found that the quantification of forest pattern with MSPA is sensitive to scale. Differences in initial
composition and configuration influence the amount but not the general tendencies of the variations of morphological spatial
pattern (MSP) class proportions with scale. Increase of P led to data generalization resulting in either a removal of the
small size features or their potential transformation into other non-core MSP classes, while an increase of S decreases the
MSP core area and this process may transform small core areas into the MSP class islet. We established that the behavior of
the MSPA classes with changing scale can be categorized as consistent and robust scaling relations in the forms of linear,
power, or logarithmic functions over a range of scales. 相似文献
8.
Science for action at the local landscape scale 总被引：4，自引：4，他引：0
Paul Opdam Joan Iverson Nassauer Zhifang Wang Christian Albert Gary Bentrup Jean-Christophe Castella Clive McAlpine Jianguo Liu Stephen Sheppard Simon Swaffield 《Landscape Ecology》2013,28(8):1439-1445
For landscape ecology to produce knowledge relevant to society, it must include considerations of human culture and behavior, extending beyond the natural sciences to synthesize with many other disciplines. Furthermore, it needs to be able to support landscape change processes which increasingly take the shape of deliberative and collaborative decision making by local stakeholder groups. Landscape ecology as described by Wu (Landscape Ecol 28:1–11, 2013) therefore needs three additional topics of investigation: (1) the local landscape as a boundary object that builds communication among disciplines and between science and local communities, (2) iterative and collaborative methods for generating transdisciplinary approaches to sustainable change, and (3) the effect of scientific knowledge and tools on local landscape policy and landscape change. Collectively, these topics could empower landscape ecology to be a science for action at the local scale. 相似文献
9.
Longterm (45 years) temporal data were used to assess the influence of spatial scale on temporal patterns of a semi-arid west Texas grassland. Temporal basal area dynamics of common curlymesquite (Hilaria belangeri (Steud.) Nash) collected from permanent plots within two areas that were released from disturbance (longterm overgrazing and drought), were evaluated at two spatial scales (quadrat, site). Wiens (1989) proposed hypotheses to characterize the influence of scale on variability, predictability, and equilibrium. These hypotheses were tested for this grassland and temporal patterns observed were different for each spatial scale. The large scale (site) was characterized by low variation between units, high variation within units, high potential predictability, and possible movement toward a fluctuating but relatively stable or equilibrial state. At the small scale (quadrat), variation between units was high, predictability low, and there was no indication of movement toward a stable state; chaotic behavior may be expressed at this scale although the length of the temporal record may not be sufficient to evaluate this phenomenon. 相似文献
10.
The effect of spatial scale on Konza landscape classification using textural analysis 总被引：6，自引：0，他引：6
Spatial scale is inherent in the definition of landscape heterogeneity and diversity. For example, a landscape may appear heterogeneous at one scale but quite homogeneous at another scale. In assessing the impact of burning and grazing on the Konza Prairie Research Natural Area (a tallgrass prairie), spatial scale is extremely important. Textural contrast algorithms were applied to various scales of remote sensing data and related to landscape units for assessment of heterogeneity under a variety of burning treatments. Acquired data sets included Landsat multispectral scanner (MSS), with 80 m resolution, Landsat thematic mapper (TM), with 30 m resolution, and high resolution density sliced aerial photography (with a 5 m resolution). Results suggest that heterogeneous areas of dense patchiness (e.g., unburned areas) must be analyzed at a finer scale than more homogeneous areas which are burned at least every four years. 相似文献
11.
12.
Disturbances such as grazing, invading species, and clear-cutting, often act at small spatial scales, and means for quantifying
their impact on fine scale vegetation patterns are generally lacking. Here we adopt a set of landscape metrics, commonly used
for quantifying coarse scale fragmentation, to quantify fine scale fragmentation, namely the fine scale vegetation structure.
At this scale, patches often consist of individual plants smaller than 1 m2, requiring the grain of the analysis to be much smaller. We used balloon aerial photographs to map fine details of Mediterranean
vegetation (pixel size <0.04 m) in experimental plots subjected to grazing and clear-cutting and in undisturbed plots. Landscape
metrics are sensitive to scale. Therefore, we aggregated the vegetation map into four coarser scales, up to a resolution of
1 m, and analyzed the effect of scale on the metrics and their ability to distinguish between different disturbances. At the
finest scale, six of the seven landscape metrics we evaluated revealed significant differences between treated and undisturbed
plots. Four metrics revealed differences between grazed and control plots, and six metrics revealed differences between cleared
and control plots. The majority of metrics exhibited scaling relations. Aggregation had mixed effects on the differences between
metric values for different disturbances. The control plots were the most sensitive to scale, followed by grazing and clearing.
We conclude that landscape metrics are useful for quantifying the very fine scale impact of disturbance on woody vegetation,
assuming that the analysis is based on sufficiently high spatial resolution data. 相似文献
13.
Peter H. Verburg Sanneke van Asselen Emma H. van der Zanden Elke Stehfest 《Landscape Ecology》2013,28(6):1067-1080
Landscape ecology has provided valuable insights in the relations between spatial structure and the functioning of landscapes. However, in most global scale environmental assessments the representation of landscapes is reduced to the dominant land cover within a 0.5 degree pixel, disregarding the insights about the role of structure, pattern and composition for the functioning of the landscape. This paper discusses the contributions landscape ecology can make to global scale environmental assessments. It proposes new directions for representing landscape characteristics at broad spatial scales. A contribution of landscape ecologists to the representation of landscape characteristics in global scale assessments will foster improved information and assessments for the design of sustainable earth system governance strategies. 相似文献
14.
Peter M. Groffman James M. Tiedje Delbert L. Mokma Stephen Simkins 《Landscape Ecology》1992,7(1):45-53
Large scale analyses of biogeochemical processes are necessary for understanding anthropogenic effects on global climate and
environmental quality. Regional scale estimates of denitrification from forest soils in southern lower Michigan USA were produced
by stratifying the region into landscape experimental units using soil texture and natural drainage classes, and extrapolating
data to larger areas using a geographic information system (GIS). Previous landscape-scale research established relationships
between soil texture and drainage and denitrification and quantified annual denitrification N loss in nine soil texture/drainage
groups. All forest soils within the region (64 series) were assigned to one of these nine groups based on their texture and
drainage characteristics and were assigned an annual denitrification N loss value. A regional estimate of denitrification
was produced by multiplying the areal extent of each of the nine soil groups by their annual denitrification N loss value.
Loam-textured soils underlie 47% of the regional forest and accounted for 73% of the forest denitrification. Sandy soils were
found under 44% of the regional forest but produced only 5% of the regional denitrification. Clay loam soils underlie 9% of
the regional forest and produced 22% of the denitrification. Annual denitrification N loss for the region was estimated as
1.4×107 kg N/yr. We used denitrification enzyme activity (DEA) as a proxy for annual denitrification N loss to determine if the relationship
between denitrification and soil texture and natural drainage that we observed at the landscape scale held up at the regional
scale. DEA was measured in 22 soils across the region and was strongly related to soil texture and natural drainage (r2=0.61), suggesting that extrapolation of data from the landscape to the regional scale was justified. 相似文献
15.
Methods for detecting scale and dispersion of plant cover developed by Carilieet al. (1989,Landscape Ecology 2: 203–213) were adapted to information obtained from satellite imagery. Scales were found to be on the order of 100 m in
the shrub-steppe area of southeastern Washington. General agreement between the remotely sensed data and plant cover using
the variance and correlation methods of Carlileet al. indicate that remote sensing information can be used in the design of field studies for measuring the processes controlling
plant cover in semi-arid areas; the agreement also suggests that the methods have broad applicability in the determination
of scale and dispersion. 相似文献
16.
Ecological patterns and processes operate at a variety of spatial scales. Those which are regional in nature may not be effectively captured through the combination of conservation plans derived at the local level, where land use planning frequently takes place. Conversely, regional conservation plans may not identify resources important for conservation of intraregional ecological variation. We compare modeled conservation networks derived at regional and local scales from the same area in order to analyze the impact of scale effects on conservation planning. Using the MARXAN reserve selection algorithm and least cost corridor analysis we identified a potential regional conservation network for the Central Valley ecoregion of California, USA, from which we extracted those portions found within five individual counties. We then conducted the same analysis for each of the five counties. An overlay of the results from the two scales shows a general pattern of large differences in the identified networks. Especially noteworthy are the trade-offs and omissions evident at both scales of analysis and the disparateness of the identified corridors that connect core reserves. The results suggest that planning efforts limited to one scale will neglect biodiversity patterns and ecological processes that are important at other scales. An intersection of results from the two scales can potentially be used to prioritize areas for conservation found to be important at several spatial scales. 相似文献
17.
景观设计在我国起步较晚,专业人才匮乏,随着近10年中国改革开放的制度愈趋成熟及城市化建设速度的快速发展,大量海外人才将涌入中国这一巨大的新兴市场。同时,中西文化不可避免的碰撞,不同国度或地区之景观设计师对景观元素空间尺度不协调运用将极大影响我国园林事业的长远发展。 相似文献
18.
Matutini Florence Baudry Jacques Fortin Marie-Josée Pain Guillaume Pithon Joséphine 《Landscape Ecology》2021,36(12):3557-3573
Context
Species distribution modelling is a common tool in conservation biology but two main criticisms remain: (1) the use of simplistic variables that do not account for species movements and/or connectivity and (2) poor consideration of multi-scale processes driving species distributions.
ObjectivesWe aimed to determine if including multi-scale and fine-scale movement processes in SDM predictors would improve accuracy of SDM for low-mobility amphibian species compared with species-level analysis.
MethodsWe tested and compared different SDMs for nine amphibian species with four different sets of predictors: (1) simple distance-based predictors; (2) single-scale compositional predictors; (3) multi-scale compositional predictors with a priori selection of scale based on knowledge of species mobility and scale-of-effect; and (4) multi-scale compositional predictors calculated using a friction-based functional grain to account for resource accessibility with landscape resistance to movement.
ResultsUsing friction-based functional grain predictors produced slight to moderate improvements of SDM performance at large scale. The multi-scale approach, with a priori scale selection, led to ambiguous results depending on the species studied, in particular for generalist species.
ConclusionWe underline the potential of using a friction-based functional grain to improve SDM predictions for species-level analysis.
相似文献19.
María-Luisa Tello Cristina Redondo Laura Gaforio Silvina Pastor Eloy Mateo-Sagasta 《Urban Forestry & Urban Greening》2005,3(2):532
Anthracnose caused by the fungus Apiognomonia veneta (Sacc. et Speg.) Höhnel., is the most important and frequent disease affecting mature ornamental plane trees (Platanus×hybrida Brot.=P.×acerifolia (Ait.)Willd.) of central Spain. Symptoms of the disease are: leaf vein and petiole necrosis, bud death, defoliation, proliferation of shoots growing in whorls, short internodes, cankers, necrotic lesions and twigs and branches growing in angles. Based on our previous experience, a disease severity rating scale (DSRS) has been established, consisting of six levels: 0=healthy, 1=initial, 2=low, 3=medium, 4=high and 5=dead. In order to achieve a better and more efficient measure of disease intensity we tried to quantify this visual scale using mathematical criteria. In 2000, 610 mature trees up to 200 years old, divided into 4 age classes, were selected and systematically evaluated using a visual estimation based method. The trees were located in central Spain, mainly in two periurban areas of the town of Aranjuez (south of Madrid) and in three urban areas of Madrid city. Trees were observed in late spring, summer and winter. We recorded visual estimation of disease severity, foliage cover, healthy new shoots, dead branches, shoot growth in whorls and branch growth in angles. The statistical relationship between the parameters, disease severity and all the variables recorded (defoliation, healthy new shoots, etc.) has been evaluated. “Leaf density”, “dead branches” and “healthy shoots” were the variables that help to discriminate better between the different levels of the DSRS. A clearer definition of the different phases of disease severity will facilitate the application of possible control methods and the prediction of the behaviour of other Platanus spp. 相似文献
20.
Carly J. Stevens Iain Fraser Jonathan Mitchley Matthew B. Thomas 《Landscape Ecology》2007,22(6):799-809
In this paper, we ask why so much ecological scientific research does not have a greater policy impact in the UK. We argue
that there are two potentially important and related reasons for this failing. First, much current ecological science is not
being conducted at a scale that is readily meaningful to policy-makers. Second, to make much of this research policy-relevant
requires collaborative interdisciplinary research between ecologists and social scientists. However, the challenge of undertaking
useful interdisciplinary research only re-emphasises the problems of scale: ecologists and social scientists traditionally
frame their research questions at different scales and consider different facets of natural resource management, setting different
objectives and using different language. We argue that if applied ecological research is to have greater impact in informing
environmental policy, much greater attention needs to be given to the scale of the research efforts as well as to the interaction
with social scientists. Such an approach requires an adjustment in existing research and funding infrastructures. 相似文献