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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.
Brigitte Moser Jochen A. G. Jaeger Ulrike Tappeiner Erich Tasser Beatrice Eiselt 《Landscape Ecology》2007,22(3):447-459
Patch-based landscape metrics can be biased by the boundaries and the extent of a reporting unit if the boundaries fragment
patches. We call this the “boundary problem”. The effective mesh size m
eff is a convenient method to quantify landscape fragmentation, that is based on the probability that two points chosen randomly
in a region will be connected, e.g., not be separated by roads, railroads, or urban development. The cutting-out (CUT) procedure,
used in the original computation of m
eff, suffers from the boundary problem because the boundaries of the reporting units are considered to be additional barriers.
Therefore, m
eff will be underestimated, particularly if reporting units are embedded within the broader landscape. In this paper, we present
a solution to overcome this limitation by a new method called “cross-boundary connections” (CBC) procedure. It attributes
the connections between two points that are located in different reporting units to both reporting units. We systematically
compare the CBC procedure to the CUT procedure and show that the boundary problem is intrinsic to the CUT procedure, while
the CBC procedure is independent of the size and administrative boundaries of reporting units. In addition, we elucidate the
superior performance of the new procedure in the case study of South Tyrol where m
eff is being used for sustainability reporting on the level of municipalities. The new CBC procedure eliminates the bias due
to the boundaries and the size of reporting units in measuring landscape fragmentation through m
eff. 相似文献
3.
Aafke M. Schipper Kees Koffijberg Marije van Weperen Guido Atsma Ad M. J. Ragas A. Jan Hendriks Rob S. E. W. Leuven 《Landscape Ecology》2011,26(3):397-410
Understanding the driving forces behind the distribution of threatened species is critical to set priorities for conservation
measures and spatial planning. We examined the distribution of a globally threatened bird, the corncrake (Crex crex), in the lowland floodplains of the Rhine River, which provide an important breeding habitat for the species. We related
corncrake distribution to landscape characteristics (area, shape, texture, diversity) at three spatial scales: distinct floodplain
units (“floodplain scale”), circular zones around individual observations (“home range scale”), and individual patches (“patch
scale”) using logistic regression. Potential intrinsic spatial patterns in the corncrake data were accounted for by including
geographic coordinates and an autocovariate as predictors in the regression analysis. The autocovariate was the most important
predictor of corncrake occurrence, probably reflecting the strong conspecific attraction that is characteristic of the species.
Significant landscape predictors mainly pertained to area characteristics at the patch scale and the home range scale; the
probability of corncrake occurrence increased with potential habitat area, patch area, and nature reserve area. The median
potential habitat patch size associated with corncrake occurrence was 11.3 ha; 90% of the corncrake records were associated
with patches at least 2.2 ha in size. These results indicate that the corncrake is an area-sensitive species, possibly governed
by the males’ tendency to reside near other males while maintaining distinct territories. Our results imply that corncrake
habitat conservation schemes should focus on the preservation of sufficient potential habitat area and that existing management
measures, like delayed mowing, should be implemented in relatively large, preferably contiguous areas. 相似文献
4.
A multiscale framework for landscape analysis: Object-specific analysis and upscaling 总被引：13，自引：0，他引：13
Landscapes are complex systems that require a multiscale approach to fully understand, manage, and predict their behavior. Remote sensing technologies represent the primary data source for landscape analysis, but suffer from the modifiable areal unit problem (MAUP). To reduce the effects of MAUP when using remote sensing data for multiscale analysis we present a novel analytical and upscaling framework based on the spatial influence of the dominant objects composing a scene. By considering landscapes as hierarchical in nature, we theorize how a multiscale extension of this object-specific framework may assist in automatically defining critical landscape thresholds, domains of scale, ecotone boundaries, and the grain and extent at which scale-dependent ecological models could be developed and applied through scale. 相似文献
5.
Landscape analysis and delineation of habitat patches should take into account organism-specific behavioral and perceptual
responses to landscape structure because different organisms perceive and respond to landscape features over different ranges
of spatial scales. The commonly used methods for delineating habitat based on rules of contiguity do not account for organism-specific
responses to landscape patch structure and have undesirable properties, such as being dependent on the scale of base map used
for analysis. This paper presents an improved patch delineation algorithm, “PatchMorph,” which can delineate patches across
a range of spatial scales based on three organism-specific thresholds: (1) land cover density threshold, (2) habitat gap maximum
thickness (gap threshold), and (3) habitat patch minimum thickness (spur threshold). This algorithm was tested on an “idealized”
landscape with landscape gaps and spurs of known size, and delineated patches as expected. It was then applied to delineate
patches from a neutral random fractal landscape, which showed that as the input gap and spur thickness thresholds were increased,
the number of patches decreased from 59 (low thresholds) patches to 1 (high thresholds). The algorithm was then applied to
model western yellow-billed cuckoo (Coccyzus americanus occidentalis) nesting habitat patches based on spur and gap thresholds specific to this organism. Both these analyses showed that fewer
patches were delineated by PatchMorph than by rules of contiguity, and those patches were larger, had smoother edges, and
had fewer gaps within the patches. This algorithm has many applications beyond those presented in this paper, including habitat
suitability analysis, spatially explicit population modeling, and habitat connectivity analysis. 相似文献
6.
Luis J. Villanueva-Rivera Bryan C. Pijanowski Jarrod Doucette Burak Pekin 《Landscape Ecology》2011,26(9):1233-1246
In this paper we present an introduction to the physical characteristics of sound, basic recording principles as well as several
ways to analyze digital sound files using spectrogram analysis. This paper is designed to be a “primer” which we hope will
encourage landscape ecologists to study soundscapes. This primer uses data from a long-term study that are analyzed using
common software tools. The paper presents these analyses as exercises. Spectrogram analyses are presented here introducing
indices familiar to ecologists (e.g., Shannon’s diversity, evenness, dominance) and GIS experts (patch analysis). A supplemental
online tutorial provides detailed instructions with step by step directions for these exercises. We discuss specific terms
when working with digital sound analysis, comment on the state of the art in acoustic analysis and present recommendations
for future research. 相似文献
7.
Scale problems in reporting landscape pattern at the regional scale 总被引：30，自引：2，他引：28
R. V. O'Neill C. T. Hunsaker S. P. Timmins B. L. Jackson K. B. Jones K. H. Riitters J. D. Wickham 《Landscape Ecology》1996,11(3):169-180
Remotely sensed data for Southeastern United States (Standard Federal Region 4) are used to examine the scale problems involved
in reporting landscape pattern for a large, heterogeneous region. Frequency distributions of landscape indices illustrate
problems associated with the grain or resolution of the data. Grain should be 2 to 5 times smaller than the spatial features
of interest. The analyses also reveal that the indices are sensitive to the calculation scale,i.e., the unit area or extent over which the index is computed. This “sample area” must be 2 to 5 times larger than landscape
patches to avoid bias in calculating the indices.
Research sponsored by the Office of Research and Development, U.S. Environmental Protection Agency under IAG DW89934440-6
and DW89936104-01 with the U.S. Department of Energy under contract DE-AC05-84OR21400 with Martin Marietta Energy Systems,
Inc. 相似文献
8.
Determining an appropriate minimum mapping unit in vegetation mapping for ecosystem restoration: a case study from the Everglades,USA 总被引：1，自引：0，他引：1
This paper documents the analyses that were conducted with regards to investigating an appropriate Minimum Mapping Unit (MMU)
to be used to capture the potential changes in vegetation patterns for a 10,924 square km restoration project being conducted
in south Florida, USA. Spatial landscape and class metrics that were shown to change predictably with increasing grain size
were adopted from previous studies and applied to a multi-scale analysis. Specifically, this study examines the effects of
changing grain size on landscape metrics, utilizing empirical data from a real landscape encompassing 234,913 ha of south
Florida’s Everglades. The objective was to identify critical thresholds within landscape metrics, which can be used to provide
insight in determining an appropriate MMU for vegetation mapping. Results from this study demonstrate that vegetation heterogeneity
will exhibit dissimilar patterns when investigating the loss of information within landscape and class metrics, as grain size
is increased. These results also support previous findings that suggest that landscape metric “scalograms” (the response curves
of landscape metrics to changing grain size), are more likely to be successful for linking landscape pattern to ecological
processes as both pattern and process in ecological systems often operate on multiple scales. This study also incorporates
an economic cost for various grain dependant vegetation mapping scales. A final selection of the 50 × 50 m grain size for
mapping vegetation was based on this study’s investigation of the “scalograms”, the costs, and a composite best professional
judgment of seasoned scientists having extensive experience within these ecosystems. 相似文献
9.
Key issues and research priorities in landscape ecology: An idiosyncratic synthesis 总被引：46，自引：41，他引：46
Landscape ecology has made tremendous progress in recent decades, but as a rapidly developing discipline it is faced with
new problems and challenges. To identify the key issues and research priorities in landscape ecology, a special session entitled
“Top 10 List for Landscape Ecology in the 21st Century” was organized at the 16th Annual Symposium of the US Regional Association
of International Association of Landscape Ecology, held at Arizona State University (Tempe, Arizona, USA) during April 25–29,
2001. A group of leading landscape ecologists were invited to present their views. This paper is intended to be a synthesis,
but not necessarily a consensus, of the special session. We have organized the diverse and wide-ranging perspectives into
six general key issues and 10 priority research topics. The key issues are: (1) interdisciplinarity or transdisciplinarity,
(2) integration between basic research and applications,(3) Conceptual and theoretical development, (4) education and training,
(5)international scholarly communication and collaborations, and (6) outreach and communication with the public and decision
makers. The top 10 research topics are: (1) ecological flows in landscape mosaics, (2) causes, processes, and consequences
of land use and land cover change, (3) nonlinear dynamics and landscape complexity, (4) scaling, (5) methodological development,
(6) relating landscape metrics to ecological processes, (7) integrating humans and their activities into landscape ecology,
(8) optimization of landscape pattern, (9)landscape sustainability, and (10) data acquisition and accuracy assessment. We
emphasize that, although this synthesis was based on the presentations at the“Top 10 List” session, it is not a document that
has been agreed upon by each and every participant. Rather, we believe that it is reflective of the broad-scale vision of
the collective as to where landscape ecology is now and where it may be going in future.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
This collaborative essay grows out of a debate about the relationship between aesthetics and ecology and the possibility of
an “ecological aesthetic” that affects landscape planning, design, and management. We describe our common understandings and
unresolved questions about this relationship, including the importance of aesthetics in understanding and affecting landscape
change and the ways in which aesthetics and ecology may have either complementary or contradictory implications for a landscape.
To help understand these issues, we first outline a conceptual model of the aesthetics–ecology relationship. We posit that:
1. While human and environmental phenomena occur at widely varying scales, humans engage with environmental phenomena at a
particular scale: that of human experience of our landscape surroundings. That is the human “perceptible realm.”
2. Interactions within this realm give rise to aesthetic experiences, which can lead to changes affecting humans and the landscape,
and thus ecosystems.
3. Context affects aesthetic experience of landscapes. Context includes both effects of different landscape types (wild, agricultural,
cultural, and metropolitan landscapes) and effects of different personal–social situational activities or concerns. We argue
that some contexts elicit aesthetic experiences that have traditionally been called “scenic beauty,” while other contexts
elicit different aesthetic experiences, such as perceived care, attachment, and identity.
Last, we discuss how interventions through landscape planning, design, and management; or through enhanced knowledge might
establish desirable relationships between aesthetics and ecology, and we examine the controversial characteristics of such
ecological aesthetics. While these interventions may help sustain beneficial landscape patterns and practices, they are inherently
normative, and we consider their ethical implications. 相似文献
11.
Spatial and temporal analysis of landscape patterns 总被引：89，自引：0，他引：89
Monica G. Turner 《Landscape Ecology》1990,4(1):21-30
A variety of ecological questions now require the study of large regions and the understanding of spatial heterogeneity. Methods
for spatial-temporal analyses are becoming increasingly important for ecological studies. A grid cell based spatial analysis
program (SPAN) is described and results of landscape pattern analysis using SPAN are presentedd. Several ecological topics
in which geographic information systems (GIS) can play an important role (landscape pattern analysis, neutral models of pattern
and process, and extrapolation across spatial scales) are reviewed. To study the relationship between observed landscape patterns
and ecological processes, a neutral model approach is recommended. For example, the expected pattern (i.e., neutral model) of the spread of disturbance across a landscape can be generated and then tested using actual landscape data
that are stored in a GIS. Observed spatial or temporal patterns in ecological data may also be influenced by scale. Creating
a spatial data base frequently requires integrating data at different scales. Spatial is shown to influence landscape pattern
analyses, but extrapolation of data across spatial scales may be possible if the grain and extent of the data are specified.
The continued development and testing of new methods for spatial-temporal analysis will contribute to a general understanding
of landscape dynamics. 相似文献
12.
Soundscape ecology is being proposed as a new synthesis that leverages two important fields of study: landscape ecology and
acoustic ecology. These fields have had a rich history. Running “in parallel” for over three decades now, soundscape ecology
has the potential to unite these two (among other) fields in ways that provide new perspectives on the acoustics of landscapes.
Each of us was involved in the “birth” of these two fields. We each reflect here on the rich history of landscape ecology
and acoustic ecology and provide some thoughts on the future of soundscape ecology as a new perspective. 相似文献
13.
14.
Vegetation complexes of flowing-water habitats and their importance for the differentiation of landscape units 总被引：1，自引：0，他引：1
Angelika Schwabe 《Landscape Ecology》1989,2(4):237-253
An inductive method for recognizing vegetation complexes is presented. These complexes can be used to define landscape units. The method is demonstrated with regard to the river and rivulet valleys of the Black Forest in south-western Germany. It is based on surveys of locally occurring plant communities in homogeneous landscape units, using a cover-abundance scale for the areal extension of each community. The communities have first been established on the basis of the usual relevés of small homogeneous plots.The surveys are called sigma relevés (sigma = Greek for sum), Sigma relevés can be arranged in tables by the usual classification method in order to establish vegetation complexes. Characteristic and differential communities can be elaborated to characterize the vegetation complexes. The specific spatial distribution of each complex reflects certain physical-geographical and anthropo-geographical characteristics. Some applied aspects can be included for each vegetation complex, for example, lists of woody species typical for a landscape unit. From the point of view of water economy such a survey is useful since many efforts are being made to plant woody species in accordance with natural conditions along river and rivulet embankments. 相似文献
15.
Landsat imagery is routinely used to characterize stand-level forest communities, but low temporal resolution makes pixel-wise
characterization of phenology difficult. This limitation can be overcome by using multi-year imagery, but organizing Landsat
scenes by calendar date ignores phenological gradients across the landscape as well as inter-annual differences in both scene-
and pixel-wise phenology. We demonstrate how a spatially generalizable, phenologically-informed approach for re-ordering Landsat
pixels can be used to characterize spatial variations in autumn senescence in several forest tree species. Using end-of-season
estimates derived from MODIS phenology data, we determined the “days left in season” (DLiS) across Landsat images to produce
a synthesized phenological trajectory of the normalized difference infrared index (NDII). We used ground-based species composition
data in conjunction with the NDII trajectories to model autumn senescence by species. Absolute phenology differed by one and
a half to 3 weeks between northern and southern Wisconsin, USA, but we show that the relative timing of phenology for individual
species differs across regions by only 1–3 days when considering senescence with respect to the local end of the season. The
progression of species senescence was consistent in lowland stands, starting with green and black ash, followed by silver
maple, yellow birch, red maple, and tamarack. The image analyses suggest that senescence progressed more rapidly in southern
than northern Wisconsin, starting earlier but taking about ten more days in the north. Our results support the use of MODIS
phenological data with multi-year Landsat imagery to detect species with unique phenologies and identify how these vary across
the landscape. 相似文献
16.
Noémie Schaller El Ghali Lazrak Philippe Martin Jean-François Mari Christine Aubry Marc Benoît 《Landscape Ecology》2012,27(3):433-446
Landscape spatial organization (LSO) strongly impacts many environmental issues. Modelling agricultural landscapes and describing
meaningful landscape patterns are thus regarded as key-issues for designing sustainable landscapes. Agricultural landscapes
are mostly designed by farmers. Their decisions dealing with crop choices and crop allocation to land can be generic and result
in landscape regularities, which determine LSO. This paper comes within the emerging discipline called “landscape agronomy”,
aiming at studying the organization of farming practices at the landscape scale. We here aim at articulating the farm and
the landscape scales for landscape modelling. To do so, we develop an original approach consisting in the combination of two
methods used separately so far: the identification of explicit farmer decision rules through on-farm surveys methods and the
identification of landscape stochastic regularities through data-mining. We applied this approach to the Niort plain landscape
in France. Results show that generic farmer decision rules dealing with sunflower or maize area and location within landscapes
are consistent with spatiotemporal regularities identified at the landscape scale. It results in a segmentation of the landscape,
based on both its spatial and temporal organization and partly explained by generic farmer decision rules. This consistency
between results points out that the two modelling methods aid one another for land-use modelling at landscape scale and for
understanding the driving forces of its spatial organization. Despite some remaining challenges, our study in landscape agronomy
accounts for both spatial and temporal dimensions of crop allocation: it allows the drawing of new spatial patterns coherent
with land-use dynamics at the landscape scale, which improves the links to the scale of ecological processes and therefore
contributes to landscape ecology. 相似文献
17.
Tradable biodiversity credit systems provide flexible means to resolve conflicts between development and conservation land-use
options for habitats occupied by threatened or endangered species. We describe an approach to incorporate the influence of
habitat fragmentation into the conservation value of tradable credits. Habitat fragmentation decreases gene flow, increases
rates of genetic drift and inbreeding, and increases probabilities of patch extinction. Importantly, tradable credit systems
will change the level of fragmentation over time for small and/or declining populations. We apply landscape equivalency analysis
(LEA), a generalizable, landscape-scale accounting system that assigns conservation value to habitat patches based on patch
contributions to abundance and genetic variance at landscape scales. By evaluating habitat trades using two models that vary
the relationship between dispersal behaviors and landscape patterns, we show that LEA provides a novel method for limiting
access to habitat at the landscape-scale, recognizing that the appropriate amount of migration needed to supplement patch
recruitment and to offset drift and inbreeding will vary as landscape pattern changes over time. We also found that decisions
based on probabilities of persistence alone would ignore changes in migration, genetic drift, and patch extinction that result
from habitat trades. The general principle of LEA is that habitat patches traded should make at least equivalent contributions
to rates of recruitment and migration estimated at a landscape scale. Traditional approaches for assessing the “take” and
“jeopardy” standards under the Endangered Species Act based on changes in abundance and probability of persistence may be
inadequate to prevent trades that increase fragmentation. 相似文献
18.
We evaluated support for four alternate hypotheses explaining the distribution of breeding Brown-headed Cowbirds (Molothrus ater) in forests at varying distances from the forest edge in three Midwestern USA landscapes with varying amounts of forest fragmentation
(core forest area ranged from 5 to 70%). We focused on breeding cowbirds’ use of forest because of the risk of nest parasitism
to forest-dwelling hosts and to identify factors affecting breeding cowbird habitat selection. We compared distances of cowbird
locations in the forest from the forest edge (“edge distances”) to distances of random forest locations in the entire landscape
or within individual cowbird home ranges. We analyzed 1322 locations of 84 cowbirds across three landscapes. We found support
for the landscape context hypothesis that breeding cowbird preference for forest edge varied with landscape context. Ninety
percent of cowbird locations were within 150–350 m of forest edge, despite the overall availability of forest at greater distances
from edge (as far as 500–1450 m) both within cowbird home ranges and the entire forested landscape. Cowbird preference for
edge varied by landscape context largely due to differences in the availability of forest edge. In a highly fragmented forest
cowbirds utilized the entire forest and likely viewed it as “all edge.” In less fragmented forests, cowbirds preferred edge.
We consider how variation in cowbird edge preference might relate to patterns in host abundance, host diversity, and host
quality because cowbird movements indicate they are capable of using forest farther from edges. 相似文献
19.
Marion Valeix Andrew J. Loveridge Zeke Davidson Hillary Madzikanda Hervé Fritz David W. Macdonald 《Landscape Ecology》2010,25(3):337-351
Within a landscape where prey has an aggregated distribution, predators can take advantage of the spatial autocorrelation
of prey density and intensify their search effort in areas of high prey density by using area-restricted search behaviour.
In African arid and semi-arid savannas, large herbivores tend to aggregate around scarce water sources. We tested the hypothesis
that water sources are a key determinant of habitat selection and movement patterns of large free-ranging predators in such
savannas, using the example of the African lion. We used data from 19 GPS radio-collared lions in Hwange National Park, Zimbabwe.
Maps of lions’ trajectories showed that waterholes are key loci on the lions’ route-maps. Compositional analyses revealed
that lions significantly selected for areas located within 2 km of a waterhole. In addition, analysis of lions’ night paths
showed that when lions are close to a waterhole (<2 km), they move at lower speed, cover shorter distances per night (both
path length and net displacement) and follow a more tortuous path (higher turning angle, lower straightness index and higher
fractal dimension) than when they are further from a waterhole. Hence, our results strongly suggest that lions adopt area-restricted
searching in the vicinity of waterholes, and reduce their search effort to minimize the time spent far from a waterhole. They
provide an illustration of how key habitat features that determine the dispersion of prey (e.g. waterholes in this study)
have an influence on the spatial ecology and movement patterns of terrestrial predators. 相似文献
20.
Clémence Vannier Chloé Vasseur Laurence Hubert-Moy Jacques Baudry 《Landscape Ecology》2011,26(8):1053-1069
In landscape ecology, the importance of map extent and resolution on the value of landscape indices is widely discussed, but
the information content of the map, mostly derived from remote sensing images, is not. In this study, we sought (1) to understand
the influence of changes in maps’ spatial and spectral resolution of agricultural landscape elements, taking hedgerow networks
as a case study, and (2) to explore how predictions of species distribution might be affected by maps’ resolutions, taking
two carabid species as a case study. To do so, we compared maps from different remote sensors, derived two landscape characterization
variables from the maps related to patterns known to drive ecological processes, and analyzed their predictive power on biological
data distribution to assess the information content of these maps. The results show that (1) the use of several methods, including
landscape metrics, was useful to assess map validity; (2) the spatial resolution of satellite images is not the only important
factor; changes in spectral resolution significantly alter maps; (3) the relevant definition of “hedgerow” to construct functional
maps is species and process specific; thus the different maps are not either good or bad, but rather provide complementary
information; (4) the more a species responds to network structure and over small areas, the less the different maps can be
substitutable one to another. 相似文献