Ecology. The value of nature and the nature of value.

Ecosystems are capital assets: When properly managed, they yield a flow of vital goods and services. Relative to other forms of capital, however, ecosystems are poorly understood, scarcely monitored, and--in many important cases--undergoing rapid degradation. The process of economic valuation could greatly improve stewardship. This potential is now being realized with innovative financial instruments and institutional arrangements.

Economic incentives for rain forest conservation across scales.

Globally, tropical deforestation releases 20 to 30% of anthropogenic greenhouse gases. Conserving forests could reduce emissions, but the cost-effectiveness of this mechanism for mitigation depends on the associated opportunity costs. We estimated these costs from local, national, and global perspectives using a case study from Madagascar. Conservation generated significant benefits over logging and agriculture locally and globally. Nationally, however, financial benefits from industrial logging were larger than conservation benefits. Such differing economic signals across scales may exacerbate tropical deforestation. The Kyoto Protocol could potentially overcome this obstacle to conservation by creating markets for protection of tropical forests to mitigate climate change.

The fertility plateau in Costa Rica: a review of causes and remedies.

PIP: Costa Rica achieved a substantial reduction in its overall fertility rate in a very short period of time. The halving of the fertility rate which occurred in less than ten years in Costa Rica transpired over the course of 100 years in France and 170 in Sweden. The level of contraceptive use in Costa Rica is twice that in other Central American nations. The authors summarize the recent demographic history of Costa Rica and review factors influencing its remarkable fertility decline. They then discuss possible explanations for the ensuing fertility plateau and conclude by suggesting strategies for affecting a further decrease in fertility rates. With regard to the reasons for the fertility plateau, cultural factors, socioeconomic factors, declining government commitment and family planning services, education, and the Church are considered. To reduce the level of fertility even further, the authors recommend that the government adopt a clear population policy which could serve as a basis for other changes such as increased support of family planning programs, improvements in the educational system, increased women's status and employment opportunities, and extensive education in schools and through the mass media on the socioeconomic and environmental effects of overpopulation. It is important to increase Costa Ricans' understanding of the negative impacts of continued population growth and the role of individual family planning decisions in that growth.^ieng

The most overpopulated nation.

PIP: A stable population in the US in 1943 would have resulted in just 135 million people today making the import of foreign oil unnecessary. A population exerts an impact on the environment based on 3 factors: the size of the population (P), the level of per capita consumption or affluence (A), and the measure of the impact of technology (T). In the US the P factor is huge: 250 million people. The sum of A and T factors (per-capita environmental impact) is 1 1/2 times that of the Soviet Union, twice that of Britain, Sweden, France, or Australia, 14 times that of China, and 40 times that of India. Americans burn 1/4 of the world's fossil fuels spewing carbon dioxide into the atmosphere, and use chlorofluorocarbons extensively that also add to the greenhouse effect and deplete the vital ozone shield. The key to civilization's survival is the reduction of the P, A, and T factors. In rich nations this can be accomplished by much more efficient use of energy and transition toward negative population growth. The best strategy is the Holdren scenario: rich countries would reduce their per capita energy use from almost 8 kilowatts to 3 kilowatts. In poor countries, per capita use would increase from 1.2 to 3 kilowatts resulting in the same standard of living at the end of a century. To prevent longterm deterioration it will be necessary to reduce population size substantially below 10 billion. The optimum population size of the US would be around 75 million people, a permanently sustainable nation with a high quality of life.^ieng

The population explosion. Why isn't everyone as scared as we are?

PIP: Outreproducing other members of your population is the very basis of natural selection and is the driving force in the evolutionary process, however against taboo discussing over population must be discarded in order to avoid millions of people prematurely dying of hunger and disease and to maintain an environmental balance. The public mentality must be of awareness, humane action, and success in lowering population below the death rate in a very short time. The failure to do so provides fertile ground for warfare, environmental degradation, poverty, racism, religious prejudice, or sexism. America and other rich nations will experience more frequent droughts, damaged crops and famines, dying forests, smog, international conflicts, epidemics, gridlock, drugs, and crime. The authors describe the nature of the population problem and the problem of inaction in dealing with population growth. We swerve within seconds, when confronted with a car in our path, we are outraged at the Alaska oil spill for a few months, yet there is no perception of the danger of a world population growth of 7% in 4 years. Most of the world's population doubt that there are compelling reasons to halt population growth. There are dramatic ways to represent this growth and examples are given. A world population of 10 billion is just around the corner. The environmental problems looming ahead are far greater than anything confronted in the 1960s. Global warming, which leads to droughts and crop failures, and flooding, acid rain, depletion of the ozone layer, vulnerability to epidemics, and exhaustion of soils and groundwater are all related to population growth. Nature will solve the population problem if people do not choose birth control. Those people preventing population control are unaware that early death from widespread famines or epidemics will solve the problem. Scientists belonging to the Club of Earth in 1988 and participating in the international scientific forum, Global Change, in 1989, are aware of population growth's contribution to catastrophe. Media coverage is weak, but major attention is focused on Pope Paul's antibirth-control encyclicals which are an important barrier to solutions. Theoretical positions about the potential availability of food for 40 billion belies the current realities of maldistribution and the management issues in redistribution of foods.^ieng

A direct assessment of the role of genetic drift in determining allele frequency variation in populations of Euphydryas editha.

Estimates of allele frequencies at six polymorphic loci were collected over eight generations in two populations of Euphydryas editha. We have estimated, in addition, the effective population size for each generation for both populations with results from mark-recapture and other field data. The variation in allele frequencies generated by random genetic drift was then studied using computer simulations and our direct estimates of effective population size. Substantial differences between observed values and computer-generated expected values assuming drift alone were found for three loci (Got, Hk, Pgi) in one population. These observations are consistent with natural selection in a variable environment.