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Introduction

 

Other LULC Change in Carroll County areas:

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Chapter 1 - Introduction

 

There are few landscapes remaining on the Earth’s surface that have not been significantly altered or are not being altered by humans in some manner. Mankind’s presence on the Earth and his modification of the landscape have had a profound effect upon the natural environment. These anthropogenic influences on shifting patterns of land use are a primary component of many current environmental concerns as land use and land cover change is gaining recognition as a key driver of environmental change (Riebsame, et. al., 1994). Changes in land use and land cover are pervasive, increasingly rapid, and can have adverse impacts and implications at local, regional and global scales.

During the past millennium, humans have taken an increasingly large role in the modification of the global environment. With increasing numbers and developing technologies, man has emerged as the major, most powerful, and universal instrument of environmental change in the biosphere today. Both globally and in the United States, land cover today is altered primarily by direct human use (Meyer, 1995). Any conception of global change must include the pervasive influence of human action on land surface conditions and processes.

To better understand the impact of land use change on terrestrial ecosystems, the factors affecting land use must be more fully examined. Growing human populations exert increasing pressure on the landscape as demands multiply for resources such as food, water, shelter, and fuel. These socioeconomic factors often dictate how land is used regionally. Land use practices generally develop over a long period under different environmental, political, demographic, and social conditions. These conditions often vary yet have a direct impact on land use and land cover (Ojima, et. al., 1994). The interaction of nature and society and their implications on land use and land cover is a very complex phenomenon that encompasses a wide range of social and natural processes.

Land use and land cover change has become a central component in current strategies for managing natural resources and monitoring environmental change. Since the late 1960’s, the rapid development of the concept of vegetation mapping has lead to increased studies of land use and land cover change worldwide. Providing an accurate assessment of the extent and health of the world’s forest, grassland, and agricultural resources has become an important priority.

Viewing the Earth from space has become essential to comprehend the cumulative influence of human activities on its natural resource base. In a time of rapid, and often unrecorded, land use change, observations from space provide objective information of human utilization of the landscape. Over the past two decades, data from Earth sensing satellites has become important in mapping the Earth’s features and infrastructure, managing natural resources, and studying environmental change.

Remote sensing and Geographic Information Systems (GIS) are providing new tools for advanced ecosystem management. The collection of remotely sensed data facilitates the synoptic analyses of earth-system function, patterning, and change at local, regional, and global scales over time; such data also provide a vital link between intensive, localized ecological research and the regional, national, and international conservation and management of biological diversity (Wilkie and Finn, 1996).

By utilizing remote sensing technologies and implementing GIS mapping techniques, land use and land cover change of designated areas can be monitored and mapped for specific research and analysis. The dynamics of forest conversion to agricultural pastures as well as its spatial distribution and patterns are the primary focus of this research. The principal objective is to detect, delineate, and map areas that have experienced land use and land cover change, specifically, the conversion of forests to agricultural pastures, in Carroll County, Arkansas over the 15 year time period of 1984 - 1999 utilizing multi-temporal Landsat Thematic Mapper satellite imagery.

The location of study selected for this research is in part, due to the author’s partiality and fondness for the area. While spending many years growing up in the community of Eureka Springs, located in western Carroll County, anthropogenic modifications and conversions have occurred to the landscape as a result of economic and agricultural growth and development that have affected the land use and land cover of the rural countryside within Carroll County.

While the county population has experienced moderate population growth, substantial increases in agricultural, domestic animal production portrayed by statistics for Carroll County during this time period suggest that patterns of land use and land cover are changing in this rural area of Northwest Arkansas. The extent of forests in Carroll County is declining while areas comprised of agricultural pastures are expanding in order to keep pace with a rapidly growing agricultural economy. Most of the decline of these forest tracts has occurred on privately owned lands throughout Carroll County at the hands of small-scale farmers and ranchers.

The scope of this research comprises the development and creation of Carroll County land use and land cover maps for the years 1999 and 1984 as well as a land use and land cover change map, 1984 - 1999. The change map depicts areas which have experienced the conversion of forest to agricultural pastures and the regeneration of successional forests from fallow pastures over the span of 15 years between 1984 and 1999 in Carroll County. These maps were derived from the multi-temporal classification of four Landsat Thematic Mapper satellite images, dated May 7, 1999, October 6, 1999, December 25, 1999, and September 18, 1984, in addition to the development of a hierarchical land use classification for Carroll County. The land use and land cover maps for 1999 and 1984 as well as the land use and land cover change map, 1984 - 1999 were derived from the satellite imagery by utilizing standardized remote sensing classification methodologies. The 1999 land use classes accuracy is based upon ground control training data obtained by extensive Global Positioning System (GPS) field collection throughout Carroll County.

The image processing techniques employed in this study were conducted using PCI image processing software. PCI is a raster based software package with advanced vector capabilities. The classified images were exported into ArcInfo and ArcView GIS software and converted from a raster to a vector format for additional GIS analysis.

Once the areas of land use change had been delineated, an additional land assessment of these areas was conducted to determine the wisdom of such land use practices. The areas of cleared forest were analyzed comparing their slope, erodibility, and land productivity classifications. The final hardcopy land use maps were produced in ArcView and portray the areal extent of land use and land cover change in Carroll County, Arkansas over a fifteen year span from 1984 to 1999. All the computer software and hardware required in this study was utilized at The Center for Advanced Spatial Technologies at the University of Arkansas, Fayetteville.

Natural features have definite and recognizable planning implications in our utilization of the environment. It is essential, therefore, that we examine and understand both the favorable and unfavorable characteristics of these features before we make costly, and often irreversible, errors that may endanger our well-being and the delicate natural balance.

 

Chapter 2 - Study Area