Application of Resource Assessment Data to Policy Decisions in Developing Countries

Information about a nation's mineral resource potential is important in regional and national development planning. Unfortunately, it is usually not possible to determine the optimum levels of investment in mineral resource assessment activities in a developing country. In addition, there is a tendency for governments to initiate expensive resource assessment projects without an understanding of the types of decision that may be influenced by the assessment data. This paper examines ten major policy issues where decisions can be substantially influenced by resource assessment information. Governments can expect to increase their benefits from investment in resource assessment activities by linking resource assessments to specified policy decisions.     

Connectivity in an Agricultural Landscape as Reflected by Interpond Movements of a Freshwater Turtle

Abstract:  Connectivity is a measure of how landscape features facilitate movement and thus is an important factor in species persistence in a fragmented landscape. The scarcity of empirical studies that directly quantify species movement and determine subsequent effects on population density have, however, limited the utility of connectivity measures in conservation planning. We undertook a 4-year study to calculate connectivity based on observed movement rates and movement probabilities for five age-sex classes of painted turtles ( Chrysemys picta ) inhabiting a pond complex in an agricultural landscape in northern Virginia (U.S.A.). We determined which variables influenced connectivity and the relationship between connectivity and subpopulation density. Interpatch distance and quality of habitat patches influenced connectivity but characteristics of the intervening matrix did not. Adult female turtles were more influenced by the habitat quality of recipient ponds than other age-sex classes. The importance of connectivity on spatial population dynamics was most apparent during a drought. Population density and connectivity were low for one pond in a wet year but dramatically increased as other ponds dried. Connectivity is an important component of species persistence in a heterogeneous landscape and is strongly dependent on the movement behavior of the species. Connectivity may reflect active selection or avoidance of particular habitat patches. The influence of habitat quality on connectivity has often been ignored, but our findings highlight its importance. Conservation planners seeking to incorporate connectivity measures into reserve design should not ignore behavior in favor of purely structural estimates of connectivity.     

Migration effects in a stochastic multipopulation model for African bee population dynamics

The rate of northern migration of the Africanized honey bee (AHB) in the United States has recently slowed dramatically. This paper investigates the impact of migration on the equilibrium size distributions of a particular stochastic multipopulation model, namely a coupled logistic power law model. The bivariate equilibrium size distribution of the model is derived and illustrated with parameter values used to describe AHB population dynamics. In the model, the difference between the equilibrium sizes of the two populations is a measure of the effect of migration. The distribution of this difference may be approximated by a normal distribution. The mean and variance parameters for the normal are predicted accurately by a second-order regression model based on the migration rate and the maximum size of the first population. The methodology is general, and should be useful in studying the migration effect in many other applications with one-way migration.     

Effects of Roads on the Structure of Freshwater Turtle Populations

Abstract:  Road mortality has the potential to alter the structure of turtle populations because turtle populations are highly sensitive to additive sources of adult mortality. To address the issue, we captured painted turtles (   Chrysemys picta ; n = 174) and snapping turtles (   Chelydra serpentina ; n = 56) in 18 wetlands surrounded by low road density (≤1.5 km roads/km² of landscape) and 17 wetlands surrounded by high road density (>1.5 km/km²) in central New York in 2002. High road density was associated with male-biased sex ratios in painted turtles (74% vs. 54% males; p = 0.01) and snapping turtles (95% vs. 74% males; p = 0.08), whereas turtle morphology and abundance were not associated with road density. Disproportionate road mortality of females on nesting migrations is the most likely cause of skewed sex ratios.     

Postfire Management on Forested Public Lands of the Western United States

Abstract:  Forest ecosystems in the western United States evolved over many millennia in response to disturbances such as wildfires. Land use and management practices have altered these ecosystems, however, including fire regimes in some areas. Forest ecosystems are especially vulnerable to postfire management practices because such practices may influence forest dynamics and aquatic systems for decades to centuries. Thus, there is an increasing need to evaluate the effect of postfire treatments from the perspective of ecosystem recovery. We examined, via the published literature and our collective experience, the ecological effects of some common postfire treatments. Based on this examination, promising postfire restoration measures include retention of large trees, rehabilitation of firelines and roads, and, in some cases, planting of native species. The following practices are generally inconsistent with efforts to restore ecosystem functions after fire: seeding exotic species, livestock grazing, placement of physical structures in and near stream channels, ground-based postfire logging, removal of large trees, and road construction. Practices that adversely affect soil integrity, persistence or recovery of native species, riparian functions, or water quality generally impede ecological recovery after fire. Although research provides a basis for evaluating the efficacy of postfire treatments, there is a continuing need to increase our understanding of the effects of such treatments within the context of societal and ecological goals for forested public lands of the western United States.     

GEOTHERMAL ENERGY IN TRANSITION

At a time when future sources of energy are under close scrutiny, both in terms of availability and suitability, geothermal energy ranks among the candidates for inclusion in any appraisal of alternative forms of supply. The use of geothermal energy for the production of electricity and for supplying domestic and industrial heat is a comparatively recent phenomenon, and its application remains closely constrained by favourable geological conditions. Yet exploration in several countries shows that geothermal energy may emerge as an important adjunct to total energy supply in many localities. McNitt outlines some of the economic and technological parameters of this energy source. Small scale geothermal power stations are more economic and less capital intensive than conventional plants, which make them of particular interest for developing countries with small electricity systems and competing demands on limited capital resources. The principal capital expenditures in the development of geothermal sources include exploration, steam production, installation of generating plant and the cost of effluent disposal. The wider use of low grade geothermal heat is also examined, in addition to the environmental problems occurring to the development of geothermal energy. The scope for technical co-operation in the development of geothermal energy is substantial, and it is likely that this source of energy will undergo more intensive development on the local scale in the future.