Remaining tree species from the indigenous vegetation of Ankara, Turkey

The city of Ankara is located in the geographic centre of Anatolia, Turkey. In the state of nature, Anatolia was covered with forests. Due to the destructive effects of civilisations passing through Anatolia over the centuries, the forest vegetation was gradually transformed to a steppe formation. After it became the capital city, a rapid planned urbanisation process was initiated in Ankara. In the first development plan, efforts were concentrated on the south axis of the city, which harbored the greatest concentration of indigenous plant cover in the valleys.In 1974, the embassy gardens and parks on the north–south axis were declared a “Natural Conservation Area”. Despite the conservation act, change and denuding of indigenous vegetation continued all along the axis due to highly increasing development. However, these conservation areas still include tree species from the indigenous vegetation. In this study, the presidency gardens, the embassy gardens and parks in Ankara that were declared a “conservation area” were evaluated in terms of the remaining tree species from the indigenous plant cover. The study aims to indicate the level of conservation of natural habitat in Ankara and to determine whether the concept of “Natural Conservation Areas” includes the protection of biodiversity or not. Moreover, the research results aim to reveal still existing tree species of indigenous vegetation, which will enlighten us regarding future landscape planning in Central Anatolia. Trees were examined by age, height and exposition. The results show that remaining indigenous tree species of the study area grow along the former ncesu River and that the terrain on which the trees stand is mostly exposed to the southwest and southeast. The indigenous tree species which do not exist in the study area are scattered in valleys along the river trails or on the hills of Ankara’s rural lands.     

Integrating Forest Carbon Sequestration Into a Cap-and-Trade Program to Reduce Net CO2 Emissions

Problem: Most research on planning to mitigate climate change has focused on reducing CO2 emissions from coal-f?red power plants or the transportation sector. The contribution of forests to lowering net CO2 emissions has largely been overlooked. U.S. forests already offset about one eighth of the nation's annual CO2 emissions and have the potential to offset more, all at a relatively low cost. It will not be easy to integrate forest carbon sequestration into a cap-and-trade program to reduce net CO2 emissions, however.

Purpose: I explore what forest land use planning, forestry management practices, and land preservation strategies would be required to integrate forest carbon seques-tration into a cap-and- trade program, and explain the role planning and planners can play in promoting forest carbon seques-tration.

Methods: The Regional Greenhouse Gas Initiative is a 10-state cap-and-trade program to reduce greenhouse gas emissions from coal-f?red power plants in the northeastern United States. It provides a case study of how forest carbon sequestration can be included in a cap-and-trade program. Meanwhile, California has devised certif?able carbon credits from forestland. I analyze both approaches and generalize from them.

Results and conclusions: To promote forest carbon sequestration through a cap-and-trade program will require ensuring the permanence of CO2 reductions, minimizing leakage from forestland conversion, and obtaining prices for carbon offsets that are high enough to induce forestland owners to participate in the program and offer them for sale. The capital needed to purchase and monitor permanent forest conservation easements as well as to provide a stream of annual income for timberland owners may require a national system of carbon credits. Ideally, the easements would be set up in advance through investments by govern-ment or nonprof?ts, so that landowners will be ready to sell credits when they are demanded.

Takeaway for practice: A cap-and-trade system could be a cost-effective way to lower net CO2 emissions if it included certif?able, tradable credits from forestland preservation and management, and if the price of carbon credits were high enough to induce forest landowners to offer credits. To promote forest carbon sequestration, planners in rural areas should work with the local, state, and federal governments and nonprof?t land trusts to zone forestland at low densities, to preserve forest land through acquiring conservation ease ments, and to fashion forest management plans that ensure long cycles of timber harvesting. Planners in metropolitan areas should promote tree planting and tree retention ordinances to protect, expand, and manage urban forests to absorb greenhouse gases.

Research support: None.     

A tool for tracking floodplain age land surface patterns on a large meandering river with applications for ecological planning and restoration design

An alluvial river channel typically meanders by eroding its outer banks and depositing sediments on the inside of bends, producing new land surfaces. Over time the landscape pattern created by these processes is important to the understanding of riparian plant ecology and the spatial structure of riparian forest development for restoration planning and design as well as other purposes. The middle sector of the Sacramento River is an actively meandering channel that deposits sediments in discrete new areas from fluvial geomorphic events creating a land age gradient. Newly formed land undergoes a primary succession by woody species such as willow and cottonwood communities that provide habitat for important conservation target species in California. Conservation and restoration of primary and secondary successional processes is an important management goal on the Sacramento River. The objectives of this paper were: (1) to develop and codify new methods to track the surficial chronological patterns of floodplain land age in a meandering river system, and (2) to analyze land production and the spatial distributions of gravel bars, riparian vegetation communities, and forest structure in relation to the land age gradient. Results from the ecological analysis indicate 71% of extant riparian vegetation was located within the 101-year meander zone; willow (18%) and cottonwood (31–43%) had the highest proportional canopy cover on lands aged 1–9 and 10–44 years, respectively. Potential applications of this approach for conservation and restoration planning and design of alluvial river floodplains are discussed.     

Ecological and social evaluation of landscape in a rural area with terraced paddies in southwestern Japan

Since the 1960s, improving socio-economic conditions in rural Japan have led to the rise in man-made or man-shaped landscapes, which has in turn resulted in formerly abundant species becoming endangered. In order to conserve biodiversity in rural areas, former agricultural landscapes must be conserved. The problem is that ecologically appropriate landscapes are not always compatible with the needs of local residents or land owners. Prior to carrying out any particular conservation measures, regional landscape management must consider both ecological and social approaches and present acceptable approach-specific management goals in an open and transparent manner. This study, undertaken in the Ohaga district of southwestern Japan, a typical rural area with terraced paddy fields, sought to develop a framework for evaluating regional resources from a landscape ecology perspective. Monitoring the temporal change of landscape structures and vegetation revealed the presence of habitats, such as the pine forest and grasslands bordering the rice paddies, which harbour specific plant species or populations, some now endangered. From a social standpoint, questionnaires revealed that local inhabitants wanted landscape management options which would conserve the pine forest, paddy fields and levee grasslands. Local farmers thought that the landscape should be used and managed as a rural park, rather than for agricultural purposes. These desirable landscape element types can serve as targets for conservation, but ultimately a new system of agricultural management must be developed to sustain the rural landscape.     

Assessing risk of large-scale habitat conversion in lightly settled landscapes

Conversion of relatively “wild” areas constitutes a rising threat to the ecological integrity of North American landscapes. As developers seek unprotected, amenity-rich lands, conservation planners require methods to recognize risk and prioritize actions. Most development models and processes are incremental, accumulating change over time and space. By contrast, large-scale amenity development can be rapid and extensive, necessitating “rapid assessment” techniques. For undeveloped lakeshores in the Northern Appalachian/Acadian ecoregion (330 000 km²), we developed a geospatial screening process based on four factors: (1) urban area proximity, (2) attractiveness of amenity (size), (3) regulatory gaps in protection, and (4) likelihood that owners will develop. To assess conversion risk, we added developable zones to the 10 783 large lakes and ponds in the ecoregion and assessed risk to these lands based on four factors at two distances from 15 major urban areas in the region. Thirty-eight of 387 landowners were classified most likely to convert their lands through development, and 11 of these accounted for 97.5% of the total high-risk habitat area (625–1118 km²). Nearly all of the at-risk land (94.6%) lay outside of currently settled areas and most (69.1%) under the purview of a single regulatory agency, the Land Use Regulatory Commission of Maine (LURC). Without rigorous planning by such agencies large-scale, highly dispersed, and rapid conversion of lightly settled, amenity-rich forestland threatens habitat degradation at multiple spatial scales, i.e., local ecosystems themselves (e.g., lakes), surrounding landscapes, and regions.     

LOCAL KNOWLEDGE OF SWIDDEN FARMERS AND CHALLENGES FOR SUSTAINABLE LAND USE: LESSONS FROM A WATERSHED MANAGEMENT PROJECT IN NORTHERN LAOS

In Laos, located in mainland Southeast Asia, shifting cultivation has been one of the important means of livelihood, in terms of food security as well as religious and cultural anchorage, for local communities in a number of areas, especially in upland areas in the country. In Pakbeng District, Oudomxay Province, northern Laos, due to the implementation of various land and forest management policies and a village relocation and consolidation program, local communities were restricted from access to the forests and faced a shortage of agricultural lands. After facing difficulties in securing sufficient lands, the local farmers used the forests in a destructive manner. The author of this article was engaged with the Community-based Watershed Management Project, as a program director of an environmental NGO and tackled challenges to achieve a land and forest management system suitable for land use by local communities. The NGO attempted to apply an alternative approach to incorporate swidden farmers’ land use system into official land and forest management institutions.     

Evaluation of an ecological land type classification system, Natchez Trace State Forest, western Tennessee, USA

In an effort to aid future research and forest management decisions, we incorporated data on forest type, soils and topography into a geographic information systems (GIS)-based ecological land classification system for Natchez Trace State Forest (NTSF) in western Tennessee. The area is still recovering from the effects of cultivation, logging, forest clearing and grazing during the 1800s and early 1900s, but the data indicated that most stands now contain sawtimber-sized trees after more than 50 years of secondary succession. Our analyses showed that forest types were not randomly associated with soil characteristics or topography. For example, the most heavily gullied lands were strongly associated with pine forests while hardwoods were more associated with upland soils and certain types of sideslopes. Mature hardwood stands, which were deemed to be of the greatest conservation value, were classified into eight ecological land types based on soil type, aspect, orientation and topographic setting for further study. When these land types were evaluated with respect to data on forest composition and environmental conditions collected in the field, we found that the variables used to derive the eight classes were important in influencing floristic patterns. It was, however, clear that the classes themselves imperfectly captured patterns of overstory community composition for a number of reasons. Thus, while land types provide a potentially valuable management tool, their utility and successful implementation are dependent upon a recognition of their inherent limitations.     

Spatial and temporal dynamics of land use pattern in Turkey: A case study in İnegöl

Recognition and understanding of landscape dynamics as a historical legacy of disturbances are necessary for sustainable management of forest ecosystems. This study analyzed forest dynamics and spatial–temporal changes in land use/land cover pattern in a sub-temperate like alluvial forest land with 1778 km² area along the Eagan Sea coast of Turkey (İnegöl). This area is studied by comparing Landsat images from 1987 to 2001 and evaluated with spatial analyses of forest cover type maps from 1972, 1983, 1993 to 2004 using GIS. The study investigated temporal changes of spatial structure of forest conditions over the period using Fragstats™.The results showed that the forested areas increased both in between 1972 and 1993 years (3.3%) and between 1987 and 2001 years (6.7%). In terms of spatial configuration, İnegöl forests are generally fragmented in the latter periods due to intensive forest utilization, illegal use, expansion of settlements and infrastructural development in the lowlands. Land use pattern significantly changed over time depending on a few factors such as unregulated management actions, social pressure and demographic movements. In conclusion, land use changes have developed in favor of forestry over time between 1972–1993 and 1987–2001. The study revealed that demographic movements have a minor effect on landscape dynamics. Both spatial and temporal changes and the factors affecting these changes should be determined for developing sustainable management of forest resources.     

Regional land pattern assessment: development of a resource efficiency measurement method

Debate on the sustainability of human settlements has recently been focused primarily on the urban portion of the land use pattern. However, urban areas rely on suburban, rural, and other less densely settled lands for their existence. In order to quantify the impacts of various land patterns on their supporting resources, these exurban lands must be included in any sustainability assessment. This need for a regional view has resulted in a measurement method that enables comparisons of relative sustainability between various regional land use patterns. Existing methods employed to assess urban sustainability are reviewed and compared with the regional characteristic curves method, introduced here, that takes a more holistic regional view. Results from the application of the method are presented, displaying the spatial dimension it brings to the analysis of illustrative primary metrics as well as demonstrating its ability to spatially quantify change in these metrics over time.     

A comprehensive conservation strategy for Georgia's greenways

In 1976 the State of Georgia published the Environmental Corridor Study (K. Dawson, W. Munnikhuysen and R. Roark, 1976. Georgia Environmental Corridor Study. Office of Planning and Research, Dept. Natural Resources, Atlanta, GA). The study is a survey of greenway potential, focusing on a statewide interconnected system. The study process combined intrinsic values (natural resources, environmental quality and aesthetics) with extrinsic values (human use, accessibility, market demand and land use) and endangeredness to provide priorities for greenway conservation. In coordination with a unique program titled Heritage Trust, initiated by then-Governor Jimmy Carter to explore conservation easements, zoning and direct acquisition, the corridor study became recognized as an excellent source of information for greenway implementation. Under Heritage Trust, over 40 000 ha of land were acquired. The current governor, Zell Miller, established Preservation 2000, a program which is continuing the work of Heritage Trust for the 1990s. To quote from the recent Preservation 2000 brochure (H. Young, 1993. Preservation 2000 Program: Summary of Program and Progress. Dept. Natural Resources, Atlanta, GA). ‘By the end of 1994, the state will acquire [an additional 40 000 hectares] of natural areas, parks, greenways and other wild lands.’ The State of Georgia has also updated the corridor study in the Georgia Trails and Greenways Plan (A. Soriano, 1992. Georgia Trails and Greenways Plan. Dept. Natural Resources, Atlanta, GA), which provides technical assistance to local communities on issues of greenway planning including outdoor recreation planning process, land and water conservation programs, management issues and agency action plans. Unique to all of the planning and acquisition programs has been the hypothesis that, when site nominations are made for conservation purchase on a statewide basis irrespective of greenways, most priority conservation areas are found to be within greenway boundaries. This is certainly due to the substantial conservation potential of greenways. Of Heritage Trust nominations, 90% were within greenway corridors. This percentage has increased to 93% with the Preservation 2000 program. Greenways are increasing rapidly in importance as an overall conservation strategy in many areas throughout the world.     

Conservation practices in US agriculture and their implication for global climate change

Increase in the use of conservation practices by agriculture in the United States will enhance soil organic carbon and potentially increase carbon sequestration. This, in turn, will decrease the net emission of carbon dioxide. A number of studies exist that calibrate the contribution of various individual, site-specific conservation practices on changes in soil organic carbon. There is a general absence, however, of a comprehensive effort to measure objectively the contribution of these practices including conservation tillage, the Conservation Reserve Program and conservation buffer strips to an change in soil organic carbon. This paper fills that void. After recounting the evolution of the use of the various conservation practices, it is estimated that organic carbon in the soil in 1998 in the United States attributable to these practices was approximately 12,200,000 metric tons. By 2008, there will be an increase of approximately 25%. Given that there is a significant potential for conservation practices to lead to an increase in carbon sequestration, there are a number of policy options that can be pursued. These include education and technical assistance, financial assistance, research and development, land retirement and regulation and taxes.     

Expansion of the US wildland–urban interface

For at least two decades, expansion of low-density residential development at the wildland–urban interface has been widely recognized as a primary factor influencing the management of US national forests. We estimate the location, extent, and trends in expansion of the wildland–urban interface (WUI) in the continental United States. We mapped the WUI by determining the intersection of housing density classes computed from refined US Census data with a map of wildfire hazards based on broad forest types using definitions of WUI from the Federal Register. Our methods allowed us to provide a more spatially precise estimation of the WUI that better reflects development patterns of interest to forest land managers. We defined three wildfire hazard classes based on vegetation type. “High” severity applies to vegetation types in which stand-replacing fires dominate both historical and recent fire regimes, e.g., lodgepole pine forest. “Low” severity applies where fuels and climate foster mostly low-intensity fires, e.g., aspen-birch forest. “High (historically low or variable)” applies to vegetation types in which fires historically were of low or variable intensity, but recently have often burned at high intensity because of a century of fire exclusion, e.g., southwestern ponderosa pine forest. In 2000, the WUI that includes a 3.2 km community protection zone occupied 465,614 km², and contained over 12.5 million housing units. This is an expansion of over 52% from 1970, and by 2030 the WUI is likely to expand to at least 513,670 km² with the greatest expansion occurring in the intermountain west states. Roughly 89% of the WUI is privately owned land and about 65% of the WUI occurs in high or high (historically low or variable) severity fire regime classes.     

Land development, land use, and urban sprawl in Puerto Rico integrating remote sensing and population census data

The island of Puerto Rico has both a high population density and a long history of ineffective land use planning. This study integrates geospatial technology and population census data to understand how people use and develop the lands. We define three new regions for Puerto Rico: Urban (16%), Densely Populated Rural (36%), and Sparsely Populated Rural (48%). Eleven percent of the island is composed of urban/built-up surfaces. A large part of these developments occur in both low-density patterns of construction and sparsely populated neighborhoods. Half of the urban development occurs outside of urban centers. This analysis helps differentiate zones in the landscape with different uses and conditions, identifying not only urban and rural settings, but also the interface where development occurs in a territory dominated by forests and pastures, analogous to a wildland urban interface. The ineffective plan of land development has left a high degree of urban sprawl in 40% of island, where cities and towns appear typically surrounded by sprawl. The San Juan Metropolitan Area is one of the most expanded urbanized areas with a population of 2–2.5 million, comparable with the most sprawled cities of the U.S. mainland. This study reinforces the need for an efficient land use planning, and provides information to support research and planning efforts related to land development and conservation. It represents the first approach integrating satellite imagery with population census data for studying the human environment in the Caribbean.     

The dynamics of tree cover change in a rural Australian landscape

This study investigated the change in tree cover in a 130 000 ha rural landscape near Bathurst, New South Wales, Australia between 1954 and 1989. Using aerial photographs, tree cover was assessed using five cover classifications (<2% cover, 2.1–25%, 25.1–50%, >50% or exotic pine plantation), with the resulting data analysed using a Geographic Information System. Overall, there was a loss of woodland/forest and an increase in the area of cleared land and Pinus radiata plantations over 35 years. Although some regeneration of woodland/forest cover occurred on marginal farmland, the general trend of loss and fragmentation has serious ramifications for nature conservation and agricultural production. The eastern and western portions of the study area exhibited quite different patterns in tree cover change, highlighting the need for examining landscapes at appropriate spatial and temporal scales.     

Landscape influence on recent rural migration in the U.S.

This study of recent rural (nonmetropolitan) migration in the U.S. finds that, consistent with research on landscape preferences, people have been most drawn to areas with a mix of forest and open land, water area, topographical variation, and relatively little cropland. A simultaneous equation model of 1990–2000 change in jobs and net migration indicates that landscape features influenced migration directly, not through effects on employment. An inordinate rise in housing values in the most highly scenic areas in 1990–2000 was associated with an exceptional slowing of migration to those areas in 2000–2005, an indication that housing supply constraints such as land use regulation may now be dampening the ties between landscape preferences and migration in rural areas. The study findings on current habitat selection are particularly interesting given the frequent conjecture that landscape preferences are adaptive, reflecting the most suitable habitats for early man.     

Land use dynamics and landscape history in La Montaña, Campeche, Mexico

Current status and trends of deforestation are assessed for the region of La Montaña, Campeche, Mexico, a buffer zone for the Calakmul Biosphere Reserve, by interpreting remotely sensed satellite image data. A change detection analysis of three satellite images was used to assess forest clearing for agriculture from two time periods (1988–2000 and 2000–2005). Buffers from specific variables (distance to roads, distance to settlements and proximity to lowland flooded forest) were used to assess deforestation patterns and identify potential variables that determine land use change. Results show annual deforestation rates increase from 0.3% between 1988 and 2000 to 0.7% between 2000 and 2005, which indicate that forest conversion is intensifying. Deforestation appears to be prominent near lowland flooded forests on soil types identified by local people as suitable for agriculture, particularly for pasture establishment. Recent occurrence of deforestation in the area is strongly associated with soil/vegetation characteristics, infrastructure development and settlement locations while the proximate causes are related to agricultural expansion. Although the economy in the region is still greatly dependent on traditional forest management, in the last decade cattle ranching has been institutionally promoted and is an economic alternative that has been increasing in importance.     

Comprehensive concept planning of urban greening based on ecological principles: a case study in Beijing, China

Greenspace is an important part of complex urban ecosystems and provides significant ecosystem services. It benefits urban communities environmentally, esthetically, recreationally and economically. Beijing Province is in north of China, and has a total area of 16,807.8 km² and a population of about 13.8 million. This paper aims to develop a comprehensive conceptual framework for urban greening of Beijing Province based on landscape ecological principles. It attempts to answer how to establish an urban greening plan at the regional, city and neighborhood levels to achieve long-term sustainability. At the regional level, a big natural and semi-natural forest area in the northwest and an ecological buffer belt in the southeast are planned to protect the environmental quality of Beijing and provide habitats for wildlife. At the city level, a green network system of green wedges, parks and green corridors has been proposed. This green network helps to limit future urban expansion, improve urban environmental quality and serve as habitats and migration routes for wildlife. At the neighborhood level, green extensions and connections of riverside greenway, road greenway, parks and vertical greening permeate into the built-up areas. They provide open space close to residential areas and offer places for recreation. This three-level green system constitutes an integrated ecological network for urban sustainable development of Beijing. For future development of Beijing, urban parks, forestry, agriculture, water and infrastructure should be planned and designed in an integrated way. After this greenspace plan is legislated and completely realized, Beijing will develop an interconnected and integrated network of urban greenspaces. It has the prospect of achieving the aim of “Green Olympic City 2008” and the long-term goal of developing Beijing towards an “Eco-City”.     

Impacts of climate and land‐cover changes on water resources in a humid subtropical watershed: a case study from East Texas,USA

This study investigates the response of water resources regarding the climate and land‐cover changes in a humid subtropical watershed during the period 1970–2009. A 0.7°C increase in temperature and a 16.3% increase in precipitation were observed. Temperature had a lower increase trend, and precipitation showed definite increasing trend compared to previous studies. The main trend of land‐cover change was conversion of vegetation and barren lands to developed and crop lands affected by human intervention, and forest and grass to bush/shrub which considered to be caused by natural climate system. Hydrologic responses to climate and land‐cover changes resulted in increases of surface run‐off (15.0%), soil water content (2.7%), evapotranspiration (20.1%) and a decrease in groundwater discharge (9.2%). We found that surface run‐off is relatively stable with precipitation, whereas groundwater discharge and soil water content are sensitive to changes in land cover, especially land cover brought about by human intervention.     

Assessment of land grabbing from protected forest areas of Bhawal National Park in Bangladesh

Land grabbing has become the major problem in all the protected forest areas of Bangladesh during the last two decades. The study was conducted in Bhawal National Park, the tropical moist deciduous Sal (Shorea robusta C.F. Gaertn) forest ecosystem of Bangladesh. This area is going through a critical situation caused by industrial revolution. Already, 255.3 ha forest lands have been grabbed by 354 illegal industrial set-ups from the study area. In this study, grabbing of protected forestland by industries, their types, future grabbing trends, increasing population inside the forest area, causal factors of grabbing and impact on biodiversity have been analysed. Increasing practical conservation efforts supported by strong political will and ordinance for specific areas is essential to conserve the protected areas. Community-based conservation approaches need to be applied for mass awareness regarding the value of this ecosystem for sustainability.     

From dust to dose: Effects of forest disturbance on increased inhalation exposure

Ecosystem disturbances that remove vegetation and disturb surface soils are major causes of excessive soil erosion and can result in accelerated transport of soils contaminated with hazardous materials. Accelerated wind erosion in disturbed lands that are contaminated is of particular concern because of potential increased inhalation exposure, yet measurements regarding these relationships are lacking. The importance of this was highlighted when, in May of 2000, the Cerro Grande fire burned over roughly 30% of Los Alamos National Laboratory (LANL), mostly in ponderosa pine (Pinus ponderosa) forest, and through areas with soils containing contaminants, particularly excess depleted and natural uranium. Additionally, post-fire thinning was performed in burned and unburned forests on about 25% of LANL land. The first goal of this study was to assess the potential for increased inhalation dose from uranium contaminated soils via wind-driven resuspension of soil following the Cerro Grande Fire and subsequent forest thinning. This was done through analysis of post-disturbance measurements of uranium air concentrations and their relationships with wind velocity and seasonal vegetation cover. We found a 14% average increase in uranium air concentrations at LANL perimeter locations after the fire, and the greatest air concentrations occurred during the months of April-June when wind velocities are highest, no snow cover, and low vegetation cover. The second goal was to develop a methodology to assess the relative contribution of each disturbance type towards increasing public and worker exposure to these resuspended soils. Measurements of wind-driven dust flux in severely burned, moderately burned, thinned, and unburned/unthinned forest areas were used to assess horizontal dust flux (HDF) in these areas. Using empirically derived relationships between measurements of HDF and respirible dust, coupled with onsite uranium soil concentrations, we estimate relative increases in inhalation doses for workers ranging from 15% to 38%. Despite the potential for increased doses resulting from these forest disturbances, the estimated annual dose rate for the public was <1 microSv yr(-1), which is far below the dose limits for public exposures, and the upper-bound dose rate for a LANL worker was estimated to be 140 microSv yr(-1), far below the 5 x 10(4) microSv yr(-1) occupational dose limit. These results show the importance of ecosystem disturbance in increasing mobility of soil-bound contaminants, which can ultimately increase exposure. However, it is important to investigate the magnitude of the increases when deciding appropriate strategies for management and long-term stewardship of contaminated lands.