Intervening in evolution: ethics and actions.

Biologists should help to guide a process of cultural evolution in which society determines how much effort, if any, is ethically required to preserve options in biological evolution. Evolutionists, conservation biologists, and ecologists should be doing more research to determine actions that would best help to avoid foreclosing evolutionary options.

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.

Population diversity: its extent and extinction.

Genetically distinct populations are an important component of biodiversity. This work estimates the number of populations per area of a sample of species from literature on population differentiation and the average range area of a species from a sample of distribution maps. This yields an estimate of about 220 populations per species, or 1.1 to 6.6 billion populations globally. Assuming that population extinction is a linear function of habitat loss, approximately 1800 populations per hour (16 million annually) are being destroyed in tropical forests alone.

Nocturnality and species survival.

Surveys of butterfly and moth diversity in tropical forest fragments suggest that nocturnality confers a dispersal, and possibly a survival, advantage. The butterfly faunas of smaller fragments were depauperate; in contrast, the species richness of nocturnal moths was similar in all fragments and even in pasture. The lack of correlation between butterfly and moth species richness among fragments (r2 = 0.005) is best explained by movements of moths at night when ambient conditions in forest and pasture are most similar; butterflies face substantial daytime temperature, humidity, and solar radiation barriers. This interpretation is supported by information on birds, beetles, and bats.

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

Double keystone bird in a keystone species complex.

Species in a Colorado subalpine ecosystem show subtle interdependences. Red-naped sapsuckers play two distinct keystone roles. They excavate nest cavities in fungus-infected aspens that are required as nest sites by two species of swallows, and they drill sap wells into willows that provide abundant nourishment for themselves, hummingbirds, orange-crowned warblers, chipmunks, and an array of other sap robbers. The swallows thus depend on, and the sap robbers benefit from, a keystone species complex comprised of sapsuckers, willows, aspens, and a heartwood fungus. Disappearance of any element of the complex could cause an unanticipated unraveling of the community.

Biodiversity studies: science and policy.

Biodiversity studies comprise the systematic examination of the full array of different kinds of organisms together with the technology by which the diversity can be maintained and used for the benefit of humanity. Current basic research at the species level focuses on the process of species formation, the standing levels of species numbers in various higher taxonomic categories, and the phenomena of hyperdiversity and extinction proneness. The major practical concern is the massive extinction rate now caused by human activity, which threatens losses in the esthetic quality of the world, in economic opportunity, and in vital ecosystem services.

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

An exploratory model of the impact of rapid climate change on the world food situation.

A simple, globally aggregated, stochastic-simulation model was constructed to examine the effects of rapid climatic change on agriculture and the human population. The model calculates population size and the production, consumption and storage of grain under different climate scenarios over a 20-year projection time. In most scenarios, either an optimistic baseline annual increase of agricultural output of 1.7% or a more pessimistic appraisal of 0.9% was used. The rate of natural increase of the human population exclusive of excess hunger-related deaths was set as 1.7% per year and climatic changes with both negative and positive impacts on agriculture were assessed. Analysis of the model suggests that the number of hunger-related deaths could double (with reference to an estimated 200 million deaths in the past two decades) if grain production keeps pace with population growth but climatic conditions are unfavourable. If the rate of increase in grain production is about half that of population growth, the number of hunger-related deaths could increase about fivefold (over past levels); the impact of climatic change is relatively small under this imbalance. Even favourable climatic changes that enhance agricultural production may not prevent a fourfold increase in deaths (over past levels) under scenarios where population growth outpaces production by about 0.8% per annum. These results may foreshadow a fundamental change where, for the first time, absolute global food deficits compound inequities in food production and distribution in causing famine. The model also highlights the effectiveness of reducing population growth rates as a strategy for minimizing the impact of global climate change and maintaining food supplies for everyone.

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