Analyzing Spatio-temporal Land Cover Dynamics in an Atlantic Forest Portion Using Unsupervised Change Detection Techniques

Environmental Modeling & Assessment - Over the past decades, the Southeast Atlantic Forest in Paraíba do Sul River Valley has suffered intense deforestation and human disturbances. Due to...     

Assessing Wetland Condition on a Watershed Basis in the Mid-Atlantic Region Using Synoptic Land-Cover Maps

We developed a series of tools to address three integrated tasks needed to effectively manage wetlands on a watershed basis: inventory, assessment, and restoration. Depending on the objectives of an assessment, availability of resources, and degree of confidence required in the results, there are three levels of effort available to address these three tasks. This paper describes the development and use of synoptic land-cover maps (Level 1) to assess wetland condition for a watershed. The other two levels are a rapid assessment using ground reconnaissance (Level 2) and intensive field assessment (Level 3). To illustrate the application of this method, seven watersheds in Pennsylvania were investigated representing a range of areas (89-777 km2), land uses, and ecoregions found in the Mid-Atlantic Region. Level 1 disturbance scores were based on land cover in 1-km radius circles centered on randomly-selected wetlands in each watershed. On a standardized, 100-point, human-disturbance scale, with 100 being severely degraded and 1 being the most ecologically intact, the range of scores for the seven watersheds was a relatively pristine score of 4 to a moderately degraded score of 66. This entire process can be conducted in a geographic information system (GIS)-capable office with readily available data and without engaging in extensive field investigations. We recommend that agencies and organizations begin the process of assessing wetlands by adopting this approach as a first step toward determining the condition of wetlands on a watershed basis.     

Status of Aquatic Bioassessment in U.S. EPA Region IX

U.S. EPA Region IX is supporting bioassessment programs in Arizona, California, Hawaii and Nevada using biocriteria program and Regional Environmental Monitoring and Assessment Program (R-EMAP) resources. These programs are designed to improve the state, tribal and regional ability to determine the status of water quality. Biocriteria program funds were used to coordinate with Arizona, California and Hawaii which resulted in these states establishing reference conditions and in developing biological indices. U.S. EPA Region IX has initiated R-EMAP projects in California and Nevada. These U.S. EPA Region IX sponsored programs have provided an opportunity to interact with the States and provide them with technical and management support. In Arizona, several projects are being conducted to develop the State's bioassessment program. These include the development of a rotational random monitoring program; a regional reference approach for macroinvertebrate bioassessments; ecoregion approach to testing and adoption of an alternate regional classification system; and development of warm-water and cold-water indices of biological integrity. The indices are projected to be used in the Arizona Department of Environmental Quality (ADEQ) 2000 water quality assessment report. In California, an Index of Biological Integrity (IBI) has been developed for the Russian River Watershed using resources from U.S. EPA's Non-point Source (NPS) Program grants. A regional IBI is under development for certain water bodies in the San Diego Regional Water Quality Control Board. Resources from the U.S. EPA Biocriteria program are being used to support the California Aquatic Bioassessment Workgroup (CABW) in conjunction with the California Department of Fish & Game (CDFG), and to support the Hawaii Department of Health (DoH) Bioassessment Program to refine biological metrics. In Nevada, R-EMAP resources are being used to create a baseline of aquatic information for the Humboldt River watershed. U.S. EPA Region IX is presently working with the Nevada Division of Environmental Protection (NDEP) to establish a Nevada Aquatic Bioassessment Workgroup. Future R-EMAP studies will occur in the Calleguas Creek watershed in Southern California, and in the Muddy and Virgin River watersheds in southern Nevada, and the Walker River watershed in eastern California and west-central Nevada.     

Residential Construction, Land Use and the Environment. Simulations for the Netherlands Using a GIS-Based Land Use Model

The present generation of geographical information systems supports strategic planning processes in several ways. They are able to store, manage and analyse the enormous amount of data needed. Another more output-oriented use is the visualisation of the diversity of locational preferences and perspectives of different interest groups and stakeholders. For the simulation of (more indirect) effects of autonomous or planned developments land use modelling can be applied. A step further is the definition and implementation of a set of indicators that show the impact of land use change on different aspects of space and the environment in order to facilitate the (political) discussions, that are an essential part of strategic planning.This paper focuses on the application of a GIS-based simulation model in the framework of the Fifth National Physical Planning Report in the Netherlands. The simulation model generates future land use in the Netherlands given several growth scenarios and a spatial strategy that comprises both foreseen strategic and autonomous developments. Special attention is paid to residential construction because this is expected to be one of the major driving forces in land use changes. An analysis of residential construction for the period 1980–1995 reveals that residential construction has been relatively concentrated in areas close to existing urban areas. New town policies also played a rather strong role during this period. The presence of natural areas (woods and wetlands) plays a significant though limited role in the choice where to build new dwellings. The simulation results for the year 2020 are used to assess the effects of land use changes for a range of environmental indicators.     

A Note on the Use of Conservation Practices in U.S. Agriculture

This article measures the effect of an increase in productivityattributable to an increase in soil organic carbon associated with theincrease in the use of conservation practices in agriculture in theUnited States. Both the direct and indirect effects are calibrated. Theanalytical approach used consists of a dynamic computable generalequilibrium model composed of 14 producing sectors, 10 consumingsectors, seven household categories classified by income, and agovernment. The results suggest that the impact of a change inproductivity is an increase in output over a six year period starting in1998 in field crops. The most significant impact is felt in thelivestock sector. This is because field crops are a major input in theproduction of livestock. The food processing sector also exhibits arelatively large increase because of the increase in inputs of both fieldcrops and livestock. Manufacturing output increases primarily becauseoverall investment rises and most investment utilizes manufacturinggoods. The other producing sectors are generally unaffected by theincrease in agricultural production due to an increase in soil organiccarbon. Coincident with the increase in the production of field cropsis a relatively large decrease in the price of field crops. Othernoticeable price reductions occur in the livestock sector and the foodprocessing sector. For the consuming sectors, the consumption offood and alcohol and tobacco increase but consumption in all of theother sectors remains basically unchanged. Prices in the food andalcohol and tobacco sectors decline by about 1% while theprices in the other sectors remain static. Household welfare increasesin the aggregate by only 0.1% with this increase occurringuniformly across all household categories. Revenue received by thegovernment increases a modest 2% in response to an increase inoutput and, hence, an increase in taxes paid. The results indicate thatthere are significant production benefits for several sectors that can berealized by an increase in the use of conservation practices inagricultural production which, in turn, enhances soil organic carbon.There are a number of policy options available to promote the use ofconservation practices. These include education and technicalassistance, financial assistance, research and development, landretirement, and regulation and taxes.     

Using NDVI to Assess Vegetative Land Cover Change in Central Puget Sound

We used the Normalized Difference Vegetation Index (NDVI) in the rapidly growing Puget Sound region over three 5-year time blocks between 1986–1999 at three spatial scales in 42 Watershed Administrative Units (WAUs) to assess changes in the amounts and patterns of green vegetation. On average, approximately 20% of the area in each WAU experienced significant NDVI change over each 5-year time block. Cumulative NDVI change over 15 years (summing change over each 5-year time block) was an average of approximately 60% of each WAU, but was as high as 100% in some. At the regional scale, seasonal weather patterns and green-up from logging were the primary drivers of observed increases in NDVI values. At the WAU scale, anthropogenic factors were important drivers of both positive and negative NDVI change. For example, population density was highly correlated with negative NDVI change over 15 years (r = 0.66, P < 0.01), as was road density (r = 0.71, P < 0.01). At the smallest scale (within 3 case study WAUs) land use differences such as preserving versus harvesting forest lands drove vegetation change. We conclude that large areas within most watersheds are continually and heavily impacted by the high levels of human use and development over short time periods. Our results indicate that varying patterns and processes can be detected at multiple scales using changes in NDVIa values.     

Landscape ecosystem classification in the Cherokee National Forest,east Tennessee,U.S.A.

A landscape ecosystem classification is described for the 43 800 ha Foothills section (elevation 305 to 610 m) of the southern unit of the Cherokee National Forest. Vegetative cover, landform, and soils data were obtained from sixty 0.04 ha plots located in stands representing late successional stages. Vegetation data were grouped by dominant cover type utilizing agglomerative, hierarchical clustering and detrended correspondence analysis. Detrended canonical correspondence analysis (DCCA) and stepwise discriminant analysis (SDA) were used to identify patterns in species composition explained by environmental variables.Four community types were identified: (1) Tsuga canadensis-Acer saccharum-Fagus grandifolia-Fraxinus americana, (2) Tsuga canadensis-Rhododendron maximum, (3) Quercus prinus, and (4) Quercus prinus-Quercus coccinea-Acer rubrum. A recently developed Landform Index that quantifies slope type and degree of protection by adjacent land masses was identified through DCCA and SDA as the most important predictor of community types. The strength of the correlations between elevation and several soil thickness variables with DCCA axis 1 indicated that vegetation varies along an interpreted moisture gradient. No ecological meaning was attributed to the second axis.     

Geographic Analysis of Species Richness and Community Attributes of Forest Birds from Survey Data in the Mid-Atlantic Integrated Assessment Region

Species richness of local communities is a state variable commonly used in community ecology and conservation biology. Investigation of spatial and temporal variations in richness and identification of factors associated with these variations form a basis for specifying management plans, evaluating these plans, and for testing hypotheses of theoretical interest. However, estimation of species richness is not trivial: species can be missed by investigators during sampling sessions. Sampling artifacts can lead to erroneous conclusions on spatial and temporal variation in species richness. Here we use data from the North American Breeding Bird Survey to estimate parameters describing the state of bird communities in the Mid-Atlantic Assessment (MAIA) region: species richness, extinction probability, turnover and relative species richness. We use a recently developed approach to estimation of species richness and related parameters that does not require the assumption that all the species are detected during sampling efforts. The information presented here is intended to visualize the state of bird communities in the MAIA region. We provide information on 1975 and 1990. We also quantified the changes between these years. We summarized and mapped the community attributes at a scale of management interest (watershed units).     

State of the Estuaries in the Mid-Atlantic Region of the United States

The U.S. EPA has prepared a State of the Region Report for Mid-Atlantic Estuaries to increase knowledge of environmental condition for improved environmental management. Sources of information included the National Estuary Programs, the Chesapeake Bay Program, the state monitoring programs in Delaware, Maryland, and Virginia, Federal programs such as National Status & Trends, National Shellfish Register, National Wetlands Inventory, the Environmental Monitoring and Assessment Program, and other primary literature sources. The state of the estuarine environment was summarized using indicators for water and sediment quality, habitat change, condition of living resources, and aesthetic quality. Each indicator was briefly discussed relative to its importance in understanding estuarine condition. Wherever possible, data from multiple programs were used to depict condition. Finally, an overall evaluation of estuarine condition in the region was determined. The usefulness of monitoring programs that collect consistent information with a well-defined sampling design cannot be overemphasized.     

Innovative Environmental Education Contributes to Improved Management Practices in the Mid-Atlantic Region of the United States

The Mid-Atlantic Integrated Assessment (MAIA) and its partner, University of Maryland, Baltimore County (UMBC) have developed a graduate-level course focused on successful application of science by decision-makers to address a particular problem. Students conduct a literature review, interview the decision-makers and scientists, and synthesize and document the management problem, the science that was applied to that problem, and other issues that might constrain or drive the solution (e.g., legalities, social pressures, expense, politics, personalities, etc.). Students also quantify the results, evaluate who the intended audience is and how they most appropriately target them, and determine if there are other management problems that could be addressed with the science. The final products are short publications geared towards other decision-makers who might have a similar problem and might be seeking successful innovative solutions. MAIA is distributing these short publications to decision-makers throughout the Mid-Atlantic Region. The publications have been very positively received by state and local governments and watershed groups.     

An Interactive, Spatial Inventory of Environmental Data in the Mid-Atlantic Region

The U.S. Environmental Protection Agency (EPA) is working with federal, state, local, and non-governmental partners to produce an interactive, spatial inventory of environmental data in the mid-Atlantic region. The inventory will include maps of sampling locations, lists of measurements, and design information for hundreds of research sites and monitoring programs. It will also feature user-defined queries, resulting in customized maps that satisfy search criteria. (For example, "Display the probability-based surveys that measure dry deposition and nutrient availability in soils"). The inventory will be used in an interagency pilot study, instigated by the National Science and Technology Council's Committee on the Environment and Natural Resources, to integrate environmental monitoring and research activities. The inventory will also provide information for a regional ecological assessment led by EPA Region 3 and the Office of Research and Development. In addition, an interagency consortium will use the inventory to identify suitable field data for assessing the accuracy of satellite imagery. In each of these three applications, the inventory will be tested and evaluated as a potential prototype for completing additional regions of the U.S. Maintained as an Oracle database, the inventory is accessible on the internet at http://www.epa.gov/monitor/. Currently, ten inventory records are on-line for demonstration. The complete federal inventory of approximately 180 records will be accessible on-line by October, 1997; approximately 200 state, local and non-governmental records are scheduled for on-line access by April, 1998.     

Assessment for Salinized Wasteland Expansion and Land Use Change Using GIS and Remote Sensing in the West Part of Northeast China

Due to human impact under climatic variations, western part of Northeast China has suffered substantial land degradation during past decades. This paper presents an integrated study of expansion process of salinized wasteland in Da’an County, a typical salt-affected area in Northeast China, by using Geographic Information Systems (GIS) and remote sensing. The study explores the temporal and spatial characteristics of salinized wasteland expansion from 1954 to 2004, and land use/cover changes during this period. During the past 50 years, the salinized wasteland in study area have increased by 135,995 ha, and in 2004 covers 32.31% of the total area, in the meantime grassland has decreased by 104,697 ha and in 2004 covers only 13.15% of the study area. Grasslands, croplands and swamplands were found the three main land use types converted into salinized wasteland. Land use/cover changes shows that between 1954 and 2004, 48.6% of grasslands, 42.5% of swamplands, and 14.1% of croplands were transformed into salinized wasteland, respectively. Lastly, the major factors influencing salinized wasteland expansion and land use/cover changes were also explored. In general, climatic factors supplied a potential environment for soil salinization. Human-related factors, such as policy, population, overgrazing, and intensified and unreasonable utilization of land and water resources are the main causes of salinized wasteland expansion.     

阿图什市"十五"期间土地利用变化及分析

利用2001-2005年的遥感影像数据(覆盖范围主要是克孜勒苏柯尔克孜自治州行政辖区内的阿图什市),通过统计2001-2005 年土地利用数据,分析了该市近五年土地利用/覆盖的时空变化规律,并进而探究了导致该变化发生的自然、人文驱动因素.结果表明:在2001-2005年,该区域林地和草地面积增加,耕地面积减少,土地沙化和盐碱化现象得到遏制.探其原因主要是由社会、经济等人文因素造成,而包括气候波动在内的自然条件只是土地利用变化的背景条件.     

Spatial Validation of Land Use Change Models Using Multiple Assessment Techniques: A Case Study of Transition Potential Models

Using land use and cover change (LUCC) models for the urban growth planning, environmental assessment, and decision-making needs the establishment of an appropriate level of confidence in their performance. The objective of this research is to explore the importance of using multiple assessment techniques in order to fairly evaluate the performance of land use models. An application is conducted by using the Land Change Modeler for Ecological Sustainability (LCM) which is an empirical and transition potential model. LCM is applied to model the agricultural to developed areas transition in Rennes metropolitan area (France). The land demand is estimated using the Markov Chain model; whereas, the transition potential map is implemented using the Multi-Layer Perceptron Neural Network (MLP) method based on historical changes and driving variables. The model performance is assessed based on a variety of the most commonly used validation techniques. At the study area level, the correctness and disagreement analysis shows that LCM performs better at predicting the amount than the allocation of developed areas. Additionally, landscape metrics reveal that LCM tends to predict a fragmented urban form, which seems evident because of the large number of the individual urban patches. At the municipality level, the error budget analysis shows that the model performance, which varies highly between different subareas, needs to be improved. Moreover, the cross-tabulation between the transition potential map and both the observed and the predicted agricultural to developed areas transitions reveals that the order of the transition potential values does not perfectly fit the observed change; whereas, the predicted change is not solely limited to areas with high potential.     

Monitoring the Hydrology of Canadian Prairie Wetlands to Detect the Effects of Climate Change and Land Use Changes

There are millions of small isolatedwetlands in the semi-arid Canadian prairies. These`sloughs' are refuges for wildlife in an area that isotherwise intensively used for agriculture. They areparticularly important as waterfowl habitat, with morethan half of all North American ducks nesting inprairie sloughs. The water levels and ecology of thewetlands are sensitive to atmospheric change and tochanges of agricultural practices in the surroundingfields. Monitoring of the hydrological conditions ofthe wetlands across the region is vital for detectinglong-term trends and for studying the processes thatcontrol the water balance of the wetlands. Suchmonitoring therefore requires extensive regional-scaledata complemented by intensive measurements at a fewlocations. At present, wetlands are being enumeratedacross the region once each year and year-roundmonitoring is being carried out at a few locations. Theregional-scale data can be statistically related toregional climate data, but such analyses cast littlelight on the hydrological processes and have limitedpredictive value when climate and land use arechanging. The intensive monitoring network has providedimportant insights but it now needs to be expanded andrevised to meet new questions concerning the effects ofclimate change and land use.     

塔里木河下游土地覆盖动态变化分析

利用80－90年代的TM影响数据,借助GIS分析了新疆塔里木河下游典型生态调查区内土地利用／土地覆盖现状及动态变化,并对塔河下游土地开发效果进行了对比分析。结果显示,耕地和城镇居住住用地的增加完全来源于对草地的开垦和对荒漠胡杨林的占用。同时,由于沙化、盐咸化等自然因素的影响和因对水资源的不合理利用所产生的土壤次生盐渍化的共同作用,控制着区内生态环境不断恶化的总体态势。     

Sediment Quality of Estuaries in the Southeastern U.S.

A study was conducted to assess the condition of estuaries in the EMAP Carolinian Province (Cape Henry, VA - St. Lucie Inlet, FL). Synoptic measures of sediment contamination, toxicity, and macroinfaunal condition were made at 82 and 86 stations in 1994 and 1995, respectively, in accordance with a probabilistic sampling design. These data were used to estimate percentages of degraded vs. undegraded estuarine area from the perspective of sediment quality. Each year a sizable portion of the province (36% in 1994, 51 % in 1995) showed some evidence of either degraded benthic assemblages, contaminated sediments in excess of bioeffect guidelines, or significant sediment toxicity (based on Ampelisca abdita and Microtox® assays). However, co-occurrences of a degraded benthos and adverse exposure conditions (sediment contamination and/or toxicity) were much less extensive – 17% of the province in 1994 and 25% in 1995. Each year only four sites, representing 5% of the province in 1994 and 8% in 1995, had degraded infauna accompanied by both sediment contamination and toxicity, suggesting that strong contaminant-induced effects on the benthos (based on such combined weight-of-evidence) were limited to a fairly small percentage of estuarine area province-wide. PCBs and pesticides (lindane, dieldrin, DDT and derivatives) were the most dominant contaminants over the two-year period. The broad-scale sampling design of EMAP was not intended to support detailed characterizations of potential pollutant impacts within individual estuaries. Thus, some estuaries classified as undegraded may include additional degraded portions outside the immediate vicinity of randomly sampled sites. Such localized impacts (not accounted for in the above estimates) were detected in this study at additional nonrandom supplemental sites near potential contaminant sources.     

塔里木河干流区域土地利用遥感动态监测

介绍了TM数据在土地利用动态监测中的应用方法,通过不同时期(2000年和2002年)的TM卫星影像,单独分类结果的对比,得出塔里木河干流区域土地利用动态变化信息。     

Land Use and Climate Change Impacts on the Hydrology of the Bago River Basin,Myanmar

Assessment of land use and climate change impacts on the hydrological cycle is important for basin scale water resources management. This study aims to investigate the potential impacts of land use and climate change on the hydrology of the Bago River Basin in Myanmar. Two scenarios from the representative concentration pathways (RCPs): RCP4.5 and RCP8.5 recommended by the Intergovernmental Panel on Climate Change, Fifth Assessment Report (IPCC AR5) were used to project the future climate of 2020s, 2050s, and 2080s. Six general circulation models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) were selected to project the future climate in the basin. An increase of average temperature in the range of 0.7 to 1.5 °C and 0.9 to 2.7 °C was observed under RCP 4.5 and RCP 8.5, respectively, in future periods. Similarly, average annual precipitation shows a distinct increase in all three periods with the highest increase in 2050s. A well calibrated and validated Soil and Water Assessment Tool (SWAT) was used to simulate the land use and climate change impacts on future stream flows in the basin. It is observed that the impact of climate change on stream flow is higher than the land use change in the near future. The combined impacts of land use and climate change can increase the annual stream flow up to 68 % in the near future. The findings of this study would be beneficial to improve land and water management decisions and in formulating adaptation strategies to reduce the negative impacts, and harness the positive impacts of land use and climate change in the Bago River Basin.