Land Surface Form Research Articles

Spatiotemporal variation of the ecosystem service value in China based on surface area

The assessment of ecological assets is of great significance for protecting and using ecological resources. Traditional methods of ecological assets assessment, which adopt the planar area as the standard, often ignore the impact of the surface area, resulting in a large difference between the evaluation and the actual result. To fill this gap, this paper conducted research on ecological assets assessment based on surface area. Taking mainland China into consideration, this paper constructed a triangulation network based on 30 m resolution DEM data to simulate the real land surface form and calculate its surface area. Then, land use/cover data from 1995, 2000, 2005, 2010, and 2015 were used to estimate the ecosystem service value (ESV) and analyze its spatial variation. This paper found that: (1) The surface area of mainland China is 1.04 × 107 km2, which is 8.2 × 105 km2 larger than the planar area; (2) A huge difference was found between the total ESV based on the surface and planar area, with an absolute difference of ∼$141.66-$144.14 billion and a relative difference of ∼ 10%. For different ecosystem types, the largest difference was found in the forest ecosystem, followed by the grassland ecosystem, while the wetland ecosystem showed the smallest difference; (3) The high value of absolute difference between the ESV based on the surface and planar area was concentrated in Tibet and Northeast China. The high value of relative difference was mainly distributed in Central and Southern China. On the provincial level, the absolute difference in Tibet ranked in the first place. There was a total of 14 provinces showing a relative difference above 10%; (4) The total ESV based on surface area was basically unchanged, while various ecosystems underwent significant changes. The ESV of wetland increased by nearly 50%, while the ESV of grassland decreased by more than 10%; and (5) Change in the ESV based on surface area showed obvious spatial heterogeneity. High-High cluster was located in Tibet and the Northeast China while the Low-Low cluster was distributed in the North China Plain and Xinjiang. This paper emphasized the importance of the surface area in resource survey and asset estimation and gave more effective suggestions for ecological protection.

Sütçüler yöresi karaçam ormanlarında bitki tür çeşitliliği ve yetişme ortamı ilişkileri

Bu çalışmada Pinus nigra Arn. subsp. pallasiana (Lamb.) Holmboe meşcerelerinde alfa tür çeşitliliği ve tür zenginliği ile ekolojik ortam koşulları arasındaki ilişkilerin ortaya konulması amaçlanmıştır. Bu amaçla Sütçüler yöresinde yayılış gösteren doğal karaçam meşcerelerinden alınan örnek alanlarda bitki türlerine ait bolluk verileri Braun-Blanquet yöntemine göre kayıt edilerek, 0-1 arasında değişen örtüş-bolluk değerlerine dönüştürülmüştür. Her bir örnek alanda bitki türlerinin yanı sıra yamaç konumu, toprak derinliği, arazi yüzey formu, toprak taşlılığı verileri envanter karnesine kayıt edilmiştir. Yörenin eş yükselti haritasından elde edilen Sayısal Yükseklik Modeli (SYM) yardımıyla çevresel değişkenlerden yükselti, eğim ve bakı haritaları elde edilmiştir. Elde edilen bakı ve eğim haritalarından faydalanılarak, sıcaklık indeksi ve radyasyon indeksi haritaları oluşturulmuştur. Örnek alanlara ait alfa çeşitlilik değerlerinin hesaplanması için Shannon, Brillouin, Simpson ve Berger-Parker indislerinden yararlanılmakla birlikte, ayrıca her bir örnek alan için doğrudan tür zenginliği hesaplaması yapılmıştır. Çalışmada çeşitlilik değerleri ile çevresel değişkenler arasındaki ilişkilerin tespitine yönelik sırasıyla Pearson Korelasyon Analizi ve Temel Bileşenler Analizinden yararlanılmıştır. Uygulanan analizler neticesinde farklı alfa indislerine göre hesaplanan çeşitlilik değerlerinin karaçam ormanlarındaki yükselti ve topraktaki taşlılık oranının artmasıyla birlikte azaldığı, eğim ve sıcaklığın artmasıyla ise arttığı şeklinde bir sonuca varılmıştır. Çalışmada tür zenginliği ile çevresel değişkenler arasında önemli bir ilişki tespit edilemezken, bolluk verilerine dayalı indisler ile hesaplanan çeşitlilik değerlerinin yükselti, sıcaklık, eğim ve toprak taşlılığı değişkenleri ile önemli ilişkileri belirlenmiştir. Bu durum tür çeşitliliği-yetişme ortamı ilişkilerinin ele alındığı çalışmalarda sadece tür zenginliğinin dikkate alınmasının yeterli olmayacağı sonucunu ortaya çıkarmıştır. Ayrıca hesaplamalarda kullanılan farklı alfa çeşitlilik indislerinin çevresel değişkenlerle ilişkilerinin ortaya koyulması aşamasında da kısmi farklılıklar oluşmuştur. Dolayısıyla yapılacak olan çalışmalarda bu durumunda ayrıca göz önünde bulundurulması önem arz etmektedir.

Modeling global Hammond landform regions from 250‐m elevation data

AbstractIn 1964, E.H. Hammond proposed criteria for classifying and mapping physiographic regions of the United States. Hammond produced a map entitled “Classes of Land Surface Form in the Forty‐Eight States, USA”, which is regarded as a pioneering and rigorous treatment of regional physiography. Several researchers automated Hammond?s model in GIS. However, these were local or regional in application, and resulted in inadequate characterization of tablelands. We used a global 250 m DEM to produce a new characterization of global Hammond landform regions. The improved algorithm we developed for the regional landform modeling: (1) incorporated a profile parameter for the delineation of tablelands; (2) accommodated negative elevation data values; (3) allowed neighborhood analysis window (NAW) size to vary between parameters; (4) more accurately bounded plains regions; and (5) mapped landform regions as opposed to discrete landform features. The new global Hammond landform regions product builds on an existing global Hammond landform features product developed by the U.S. Geological Survey, which, while globally comprehensive, did not include tablelands, used a fixed NAW size, and essentially classified pixels rather than regions. Our algorithm also permits the disaggregation of “mixed” Hammond types (e.g. plains with high mountains) into their component parts.

Modeling hydrologic and geomorphic hazards across post-fire landscapes using a self-organizing map approach

Few studies attempt to model the range of possible post-fire hydrologic and geomorphic hazards because of the sparseness of data and the coupled, nonlinear, spatial, and temporal relationships among landscape variables. In this study, a type of unsupervised artificial neural network, called a self-organized map (SOM), is trained using data from 540 burned basins in the western United States. The sparsely populated data set includes variables from independent numerical landscape categories (climate, land surface form, geologic texture, and post-fire condition), independent landscape classes (bedrock geology and state), and dependent initiation processes (runoff, landslide, and runoff and landslide combination) and responses (debris flows, floods, and no events). Pattern analysis of the SOM-based component planes is used to identify and interpret relations among the variables. Application of the Davies–Bouldin criteria following k-means clustering of the SOM neurons identified eight conceptual regional models for focusing future research and empirical model development. A split-sample validation on 60 independent basins (not included in the training) indicates that simultaneous predictions of initiation process and response types are at least 78% accurate. As climate shifts from wet to dry conditions, forecasts across the burned landscape reveal a decreasing trend in the total number of debris flow, flood, and runoff events with considerable variability among individual basins. These findings suggest the SOM may be useful in forecasting real-time post-fire hazards, and long-term post-recovery processes and effects of climate change scenarios.

Computation and Elicitation of Valleyness

Existing methods for land surface form characterisation often focus on relatively simple landform element classifications and do not evaluate results with large scale participant experiments. This piece of research takes a semantics-grounded approach to characterising the landform valley. Based on definitions three algorithms to characterise valleys in a fuzzy way are introduced. Comparison of the results to assessments regarding the degree of being in a valley gained from over 800 participants in a questionnaire survey yields significant amounts of explained variance (R 2 = 0.35–0.37). Furthermore, accounting for very ambiguously perceived stimuli showing vast low places leads to markedly improved regressions (R 2 = 0.45–0.49), weighting of the data with a measure of uncertainty in judgment even more so (R 2 = 0.50–0.55).

Identifying global dust source areas using high‐resolution land surface form

Dust originates from specific, landscape‐scale (≈1–10 km) features; however, dust erodibility is commonly parameterized in global climate models using grid‐cell‐scale (≈1–5°) relationships. We examine surface characteristics from the high‐ resolution (90 m at equator) global Shuttle Radar Topography Mission digital elevation model and aerosol optical thickness (AOT) measurements from the Multiangle Imaging Spectroradiometer (MISR) instrument to find landscape‐scale characteristics common to dust producing regions. Regions with climatologically high aerosol optical thickness are associated with extremely low‐slope landscapes at ≈5 km scale that also have high‐elevation variance, likely due to aeolian features. We refer to these landscape characteristics as “levelness” and “residual landscape roughness,” and we extrapolate these relationships globally to identify geomorphologically based dust erodibility functions on the basis of levelness and residual landscape roughness criteria. We test these with the Dust Entrainment and Deposition model embedded in the Model for Atmospheric Transport and Chemistry global atmospheric tracer transport model, driven by reanalysis meteorology. The modeled global dust spatial distributions calculated with these erodibility parameters agree well with observations of MISR AOT and deposition and in the modeling framework used here represent an improvement over existing parameterizations in predicting the spatial patterns of dust sources in the Sahara and the relative amount of emission of sources in the Dust Belt to those in the Southern Hemisphere; however, agreement with observations is less good in high‐relief areas such as the Asian dust source regions, possibly because of the coarse resolution of the meteorological fields used to drive the model.

Delineation and Evaluation of Hydrologic-Landscape Regions in the United States Using Geographic Information System Tools and Multivariate Statistical Analyses

Hydrologic-landscape regions in the United States were delineated by using geographic information system (GIS) tools combined with principal components and cluster analyses. The GIS and statistical analyses were applied to land-surface form, geologic texture (permeability of the soil and bedrock), and climate variables that describe the physical and climatic setting of 43,931 small (approximately 200 km2) watersheds in the United States. (The term "watersheds" is defined in this paper as the drainage areas of tributary streams, headwater streams, and stream segments lying between two confluences.) The analyses grouped the watersheds into 20 noncontiguous regions based on similarities in land-surface form, geologic texture, and climate characteristics. The percentage of explained variance (R-squared value) in an analysis of variance was used to compare the hydrologic-landscape regions to 19 square geometric regions and the 21 U.S. Environmental Protection Agency level-II ecoregions. Hydrologic-landscape regions generally were better than ecoregions at delineating regions of distinct land-surface form and geologic texture. Hydrologic-landscape regions and ecoregions were equally effective at defining regions in terms of climate, land cover, and water-quality characteristics. For about half of the landscape, climate, and water-quality characteristics, the R-squared values of square geometric regions were as high as hydrologic-landscape regions or ecoregions.

Effect of land surface representation on forest water and carbon budgets

Forested landscapes often show very well-pronounced heterogeneity in the factors that control evapotranspiration, runoff production and carbon assimilation at a variety of length scales. In hilly or mountainous environments, strong contrasts in net radiation, available soil water, soil structure and stand characteristics can produce a large variance in both the meteorological drivers and surface resistance to carbon and water exchange with the atmosphere over distances measured in tens of metres. Because of the strong nonlinearities characterizing the influence of the environmental variables on surface resistance (particularly available soil water), the parametrization of surface process models with mean values of the environmental variables and no distribution often leads to significant bias in areal average carbon and water flux. However, it is often not feasible to incorporate directly the full distribution and patterns of the landscape for regional-scale models. Continental- and subcontinental-scale vegetation data sets currently being collected by synoptic-level satellites (e.g. the Advanced Very High Resolution Radiometer, AVHRR) do not capture the large proportion of landscape variability that exists below the resolution of the sensors. This paper explores the impacts of various landscape representation schemes that retain a range of detail in the description of land surface form and processes on simulated areal average evapotranspiration, runoff production and net carbon exchange with the atmosphere. Specific comparison is made of schemes that attempt to incorporate the topographic structure, soil and vegetation distributions of a region with schemes that sample the surface at levels similar to current coarse-resolution satellites. For strongly heterogeneous basins (mountainous topography), it is found that spatial variations in available soil water can have significant effects on areal averaged carbon and water flux rates, particularly under drying conditions, whereas the spatial variations in radiation, temperature and humidity over the terrain appear to have a lesser impact.

Predicting Attainable Water Quality Using the Ecoregional Approach

To more adequately protect receiving water bodies, government policy is leading toward adaptation of integrated management approaches that protect the integrity of the ecosystem as a whole. Approaching natural water quality is a goal of integrated water resource management. Ecoregions represent geographical areas of relatively similar land surface form, mineral availability, natural vegetation and land uses, and therefore, represent areas of relatively similar background water quality. Water quality at relatively unimpacted reference locations is representative of regional natural water quality and may be reasonably extrapolated to other similar locations within the ecoregion. These concepts were applied to the Southeastern Wisconsin Till Plains ecoregion and the Milwaukee River, Wisconsin.

Shaded relief map of U.S. topography from digital elevations

Much geologic and geophysical information that lies encoded within land surface form can be revealed by image processing large files of digitized elevations in fast machines and mapping the results. This convergence of computers, analytic software, data, and output devices has created exciting opportunities for automating the numerical and spatial study of topography. One recent result is the accompanying shaded relief map of the conterminous 48 states.A shaded relief image of topography mimics a cloud‐free monochrome aerial photograph taken at low Sun. Gray tones represent different terrain slopes and azimuths calculated from adjacent elevations stored in a uniform grid, or digital elevation model (DEM). Sun elevation and direction can be varied to generate complementary views of the same area. The synoptic coverage of these computer images is a major advantage; unlike a photograph, image extent is limited only by size of the elevation array. Shaded relief maps also are free of the distortion found in radar images and of the vegetation and cultural features that mask topographic form on Landsat and SPOT images.

Correspondence Between the Distribution of Fish Assemblages in Wisconsin Streams and Omernik's Ecoregions

-Recently, Omernik divided the conterminous United States into ecoregions, areas with similar land-surface form, soils, potential natural vegetation and land use, for management of aquatic resources. Most of Wisconsin is in four of these ecoregions. I used multivariate analyses of fish and habitat data from three size-classes of streams in western and southern Wisconsin to evaluate the correspondence between ecoregions and geographic patterns in the distribution of fish assemblages. Overall, correspondence was better than expected by chance, and improved with increasing stream size. For all three size-classes of streams, agreement between the ecoregion classification of sampling stations and a classification based on a nonhierarchical cluster analysis of fish species abundance data was statistically significant. Detrended correspondence analysis ordinations of fish data showed differences among sampling stations that were associated with ecoregion membership. Catches of several fish species differed significantly among ecoregions, even with conservative significance levels. However, the ecoregion classification was fairly imprecise, and some sampling stations were more similar to stations in other ecoregions than they were to stations in their own ecoregion. Thus, in Wisconsin, ecoregions will be most useful in setting management policies for broad geographic areas containing many streams, and less useful in dealing with limited geographic areas and individual streams. Several analyses suggested that data on four general habitat characteristics, water temperature, stream gradient, substrate composition and shoreline vegetation characteristics, could be used to develop a more precise classification of Wisconsin streams. However, unlike the ecoregion classification, this classification would probably be applicable only to Wisconsin and only to fish assemblages.

Evaluation of an Aquatic Ecoregion Classification of Streams in Arkansas

ABSTRACT The efficacy of a regional stream classification system, based on the principle that streams reflect the character of the lands they drain, was evaluated in Arkansas. The classification consisted of six aquatic ecoregions defined by relatively homogeneous types of land-surface form, soil, potential natural vegetation and land use. Fish, physical habitat and water quality were sampled in 22 streams throughout the state. Data subjected to ordination analysis generally showed greater similarity in streams within the same ecoregion than in streams in different ecoregions. The patterns developed separately from fish, physical habitat and water quality data sets were relatively concordant. The null hypothesis that the classification did not reflect fundamental differences among the streams was rejected. We concluded that a regional stream classification is potentially useful for evaluating and managing streams. The identification of regions containing streams with similar character can aid in selecting...

Ecoregions of the Conterminous United States

Abstract A map of ecoregions of the conterminous United States has been compiled to assist managers of aquatic and terrestrial resources in understanding the regional patterns of the realistically attainable quality of these resources. The ecoregions are based on perceived patterns of a combination of causal and integrative factors including land use, land surface form, potential natural vegetation, and soils. A synoptic approach similar to that used to define these ecoregions is also useful for applications of the map. Initial efforts to use the framework are at the state level of resource management; they center on aquatic ecosystems — mainly attainable ranges in chemical quality, biotic assemblages, and lake trophic state.

Correspondence between spatial patterns in fish assemblages in ohio streams and aquatic ecoregions

Land classification systems can be useful for assessing aquatic ecosystems if relationships among them exist. Because the character of an aquatic ecosystem depends to a large extent upon the character of the landscape it drains, spatial patterns in aquatic ecosystems should correspond to patterns in the landscape. To test this hypothesis, the US state of Ohio was divided into four aquatic ecoregions based on an analysis of spatial patterns in the combination of land-surface form, land use, potential natural vegetation, and soil parent material. During the period July–October 1983, fish assemblages were sampled in 46 streams that were representative of the ecoregions, and that had watersheds relatively undisturbed by human activities. Spatial patterns of the fish assemblages were examined relative to the ecoregions; distinct regional differences were identified. The assemblages differed most between the Huron/Erie Lake Plain region and the Western Allegheny Plateau region; assemblages in the Eastern Corn Belt Plains and the Erie/Ontario Lake Plain-Interior Plateau regions were intermediate. This pattern also reflects the gradient in landscape character as one moves from the northwest to the southeast of Ohio.

Regional reference sites: a method for assessing stream potentials

Field assessments of impacted streams require a control or at least an unbiased estimate of attainable conditions. Control sites, such as upstream/downstream or wilderness sites, have proven inadequate for assessing attainable ecological conditions where the control streams differ naturally from the impacted streams to a considerable degree or where different disturbances exist than those being studied. Relatively undisturbed reference sites with watersheds in areas having the same land-surface form, soil, potential natural vegetation, and land use as are predominant in large, relatively homogeneous regions are suggested as alternative control sites. These areas are considered typical of the region and therefore the sites also are considered typical of the region because their watersheds exhibit all the terrestrial variables that make that region a region. The logical basis for developing regional reference sites lies in the ability to group watersheds and common stream types into regions by integrating available maps of terrestrial variables that influence streams. Relatively undisturbed reference sites can be selected from typical areas of the regions and from transition zones where one or two of the terrestrial variables are not the predominant one(s) of the region. These reference sites are useful for estimating attainable conditions, for evaluating temporal and spatial changes in ecological integrity, for classifying attainable uses of streams, and for setting biological and environmental criteria.

土地改変研究への環境地形学的アプローチ

In the land transformation studies geomorphology mainly deals with two aspects: i.e., direct transformation and induced geomorphic processes. This paper is concerned with the latter from the perspectives of climatic geomorphology. Climatic geomorphology that attaches importance to the following aspects constitutes the essential part of environmental geomorphology applicable to land transformation studies and environmental management:1) spatial variability in land conditions, 2) spatial variability in geomorphic processes characteristic of regional and local climatic conditions, 3) variability in space and time in climatic variables operating as geomorphic agents, and4) nature and resources of the land produced through the past climatic/environmental oscillations.Based on this framework, general tendencies and implications of accelerated erosion and man-induced land deterioration in Japan are summarized so as to formulate the spatial variability in the form and intensity of induced geomorphic processes under different climatic conditions. It becomes clear that the transformation of the land surface form and cover almost always results in the enhancement of geomorphic processes characteristic of regional and local climatic conditions. Combined effects of land transformation and climatic anomalies often cause geomorphic hazards due to rapid gullying, mass movements, etc. Examples of intensification of human impact on the land caused by recent climatic anomalies are reviewed briefly.The author hopes that the concepts of environmental geomorphology introduced here may shed a new light on the fields of civil engineering responsible for a better modification and the management of terrestrial environment. In Japan, the conception that most of land properties including soils are the product of the past climatic/environmental changes and hence a non-renewable resource has hitherto been very weak. The soildification of this conception requires a positive discussion among the related fields of Quaternary research.

Estimation of Cost Elasticities for Light Density Railroad Freight Service

In this article cost elasticities for light density or branch line railroad freight service are estimated using a flexible estimation approach and a multidimensional measure of service output. Based on this analysis, it appears that railroad freight service can be usefully described as consisting of quantity, distance, bulk, and frequency characteristics. In addition, important interregional cost differences were discovered when a market distinction on the basis of differences in land surface form characteristics was adopted.