Treesearch

Improper cultivation of steep mountainous areas in Taiwan contributes to serious erosion and landslides. Regular patrol, detection, and administration of these problem areas has been an extremely difficult due to the steep and dangerous terrain of many of the forested watersheds in Taiwan. A remotely piloted vehicle (RPV) has been developed for various civil and military applications. This paper reports the results of a preliminary application of RPV in monitoring and detecting land-use changes and problem areas in inaccessible watershed areas. Preliminary results indicated that RPV, with...

Environmental degradation and inefficient use of natural resources pose a growing threat to the interests of the United States, and to the physical, economic, and social well-being of people throughout the world. In his book, Global Paradox, John Naisbit states, "We have never learned, or we have forgotten, that the environment is the basis of all life and for all production. Rather than being an interest competing with other interests for attention, it is in reality the playing field on which all interests compete ... We have consistently failed to recognized that the economic system is...

We found Lucy's Warblers breeding abundantly in mid-elevation broadleaf riparian forests in the lower Gila River valley of southwestern New Mexico. They arrived en masse in the third week of March. Patterns of singing suggested that Lucy's Warblers might raise two broods. Few were heard or seen after late July. Estimated population densities ranged from 1. 7 to 3.3 territories per ha, and Lucy's Warblers constituted up to 10% of the total bird territories in our study plots. We found 24 nests placed in cavities or behind loose bark. Large cottonwoods and willows were the preferred nesting...

Growing human populations and rapid ecological changes threaten the sustainability of the middle Rio Grande, a river corridor important to numerous species of wintering, breeding, and migrating waterfowl, shorebirds, and songbirds. We review the vegetational and human history of the middle Rio Grande, substantiate the importance of this system to landbirds in migration, relate patterns and trends of migratory bird populations to variation of stopover habitats, and present new data on stopover habitat use and biology of landbird migrants. We supplemented our review of the literature by...

A scientifically valid accuracy assessment of a large-area, land-cover map is expensive. Environmental monitoring programs offer a potential source of data to partially defray the cost of accuracy assessment while still maintaining the statistical validity. In this article, three general strategies for combining accuracy assessment and environmental monitoring protocols are described. These strategies range from a fully integrated accuracy assessment and environmental monitoring protocol, to one in which the protocols operate nearly independently. For all three strategies, features...

Consider the following example of an accuracy assessment. Landsat data are used to build a thematic map of land cover for a multicounty region. The map classifier (e.g., a supervised classification algorithm) assigns each pixel into one category of land cover. The classification system includes 12 different types of forest and land cover: black spruce, balsam fir, white-cedar, other softwoods, aspen, birch, other hardwoods, urban, wetland, water, pasture, and agriculture. The accuracy of the map must be known by a user of the map to conduct credible analyses.

The U.S. Geological Survey, in cooperation with other government and private organizations, is producing a conterminous U.S. land-cover map using Landsat Thematic Mapper 30-meter data for the Federal regions designated by the U.S. Environmental Protection Agency. Accuracy assessment is to be conducted for each Federal region to estimate overall and class-specific accuracies. In Region 2, consisting of New York and New Jersey, the accuracy assessment was completed for 15 land-cover and land-use classes, using interpreted 1:40,000-scale aerial photographs as reference data. The methodology...

This chapter was developed over a series of meetings using a group-consensus process. Our recommendations are based on published results, on information compiled in the previous chapters, on expert opinion, and on unpublished data of conservation team members. This chapter is available as temporary guidance until the Recovery Plan for the southwestern willow flycatcher is published in the Federal Register. A draft Recovery Plan has been prepared by the Technical Subgroup of the Recovery Team and is under current review by the U.S. Fish and Wildlife Service and by Implementation Subgroup...

Until the southwestern willow flycatcher was proposed for listing as an endangered species in 1993, it was subject to relatively little scientific scrutiny, in part because it is drab, prone to inhabiting dense, wet thickets, and difficult to identify and observe. Consequently, it remained one of the lesser-known of North American birds. Since that time, it has become clear that significant gaps exist in our understanding of its status, distribution, ecology, and management. Recently, many questions about the subspecies have arisen due to controversy over management actions and resulting...

The goal of this document is to describe the current status, ecology, habitat, and threats of the southwestern willow flycatcher (Empidonax traillii extimus); to offer guidance for managing and protecting this Neotropical migrant and its habitats; and to identify gaps in our knowledge of the bird and its requirements. Goals, processes, and target species for U.S. Forest Service (USFS) conservation assessments of southwestern organisms were first outlined at a meeting held by the USFS Southwestern Region on May 11-12, 1994. At that time, the Forest Service had identified the southwestern...