Treesearch

Tamarisk (saltcedar: Tamarix), an invasive exotic tree native to the Eastern Hemisphere, is currently the dominant plant species in most southwestern riparian ecosystems at elevations below 1500 m. Tamarisk alters abiotic conditions and the floral composition of native southwestern riparian ecosystems and, in turn, affects native southwestern animal communities. However, information on the overall effects of tamarisk on avifauna is somewhat conflicting and incomplete. This paper attempts to resolve conflict in the literature by addressing several questions: (1) Are there consistent broad...

Social and economic systems provide a context and rationale for rangeland management. Sustaining rangeland ecosystems requires attention to the social and economic conditions that accompany the functioning of those systems. We present and discuss economic and social indicators for rangeland sustainability that have possible relevance in the United States. A brief conceptual basis for each indicator is offered describing its potential relationship to rangelands. The importance of these indicators to other countries having different social and economic conditions is less assured.

As the largest landholder of cottonwood-dominated riparian forest or “bosque” in the 150 miles of the middle Rio Grande from the Cochiti Dam to the Bosque del Apache National Wildlife Refuge, the Middle Rio Grande Conservancy District (MRGCD; a political subdivision of the State of New Mexico) and its cooperators are implementing “fuels reduction” projects throughout the bosque. Fuels reduction is defined as the removal of exotic phreatophytes such as Tamarisk (Tamarix ramosissima) and Russian olive (Elaeagnus angustifolia), treatment of the exotic stumps or stems with herbicide, and...

Rangelands in Patagonia have been managed with a lack of regulation since the introduction of sheep in the late 1880’s. Most rangelands are under private freehold in ‘estancias’ and the rest are public and managed by small subsistence-type farmers. Natural resources of rangelands are property of the provincial states according to the Constitution, but they have no mandate or resources to monitor their condition and public support funds have not been tied to proper management. Government agencies designed in the 1990’s two range evaluation systems hat have been applied extensively but they...

Studies suggest that the Southeast is an area of primary concern with regards to the spread of alien plant species (Miller 2003, Stapanian and others 1998). Data collected by Stapanian and others in 1998 showed that Japanese honeysuckle (Lonicera japonica) occurred over 2 million acres in the Southeast, invading forests and displacing native species. Among the most important mechanisms for the early detection and prevention of the spread of nonnative species is monitoring on large spatial scales for the presence of alien species, and for the presence of vulnerable sites (in other words,...

In 2000 and 2001 a root cause analysis was conducted for the Spiny Forest Ecoregion in Madagascar, identifying the local level root causes of biodiversity loss in the ecoregion as well as the policy and institutional issues at the national and international levels that contribute to them. Most of the research was conducted in and around Tulear and Fort Dauphin. Findings will be used to develop a strategic action plan for the ecoregion. The direct threats to biodiversity loss in the ecoregion are forest clearing, land conversion, and habitat alteration. Root causes include demand for wood...

A broader concept of sustainability was introduced. Ted Heintz introduced the concept of sustainability as a life sustaining property of earth’s biosphere. Ted observed that Life in a wide variety of forms, interacting in networks of evolving relationships, has been sustained for nearly 4 billion years. Sustainability is a property of the system as a whole, a result of the structure of the relationships among its elements and processes, hence an emergent property that is different from the characteristics of the system’s elements. Clearly this awesome and miraculous achievement must be our...

The 1964 U.S. Wilderness Act has one, clear mandate to the agencies that manage wilderness: preserve the wilderness character of the area. But even though the Wilderness Act went into effect 42 years ago, and all four federal agencies that manage wilderness have policies that direct managers to preserve wilderness character, the agencies can't show whether they are preserving wilderness character or not.

This paper summarizes a select set of research studies conducted over the past 40 years, drawing conclusions on trends in public attitudes about the use of wildland fire in federally-designated Wilderness. The research includes trend studies conducted with visitors to Wilderness areas in Washington, Oregon, California, Idaho and Montana. Each research study used a unique method for measuring and tracking change in visitor attitudes towards fire in Wilderness. Across all studies, results indicate a trend toward more positive and supportive visitor attitudes about the use of fire in Wildernes...

Barring abrupt natural or anthropogenic disasters, ecological changes in terrestrial landscapes proceed at a pace not readily detected by humans. The use of historical repeat photography can provide valuable information about such changes, but, these studies are opportunistic in that they must rely on old photographs. Hence, their ecological interpretative power is compromised by the intention of the original photographer, the quality of the original photographs, an incomplete and potentially misrepresentative sampling design, and a limited analytical framework for interpreting ecological...