Biodiversity Loss and Public Health; (PART I)
Byline: Magdalena C. Cantoria, Ph.D. Member: National Academy of Science and Technology Department of Science and Technology
BIODIVERSITY has made important contributions to public health through progress in the sciences of biotechnology and genetic engineering. A major contribution is in the form of medicines to alleviate human suffering. Medicines have been drawn from nature since ancient times. At present, the chemical structures of compounds isolated from biological sources are providing leads to designing new molecules with pharmacological activity for the treatment of diseases once considered incurable. Improvements in nutrition from new strains of crops and biodegradable pesticides contribute to public health. Bioremediation to clean up toxic wastes and improve industrial ecology represents a major advance towards making industry more biologically based, leading to a greener environment, a cleaner workplace, and a healthier workforce.
I. Causes of biodiversity loss
The present and future potential of biodiversity, however, is being eroded at an alarming rate. The threats to biodiversity and the consequences for public health are gradually being recognized as a global crisis. Environmental degradation, population changes, and agro-ecosystem management transformation are some of the outstanding causes of biodiversity loss related to public health.
A. Environmental degradation
Environmental degradation leads to biodiversity loss and has serious implications for public health. Global climate change, stratosphere ozone depletion, toxic substances in the environment, and habitat destruction all have the capacity to lead to species extinction and biodiversity loss.
Global climate change is an aspect of environmental degradation with a major impact on species and biodiversity leading to the shifting of migration ranges of plants and animals to adapt to climate-altered habitats. There are evidences of species migrations and potential losses paralleling increases in recorded temperatures. Species that could not adapt have been lost either because their rates of migration were too slow or because geographical barriers like oceans, mountains, or unsuitable habitat conditions prevented their advance. Barriers to species migration exist where people live - cities, roads, agricultural lands, and other constructions would further complicate species migration. Furthermore, animals would be limited by the distribution of the plants they eat or otherwise depend on.
Other aspects of global climate change that may have a major impact on species and biodiversity include: Algal blooms fertilized by the discharge of sewage and by agricultural runoff; rising seas that may threaten species in coastal wetlands, mangrove swamps, and coral reefs; major alterations of ocean currents from sea warming and changes in salinity, with potentially enormous changes in climate and in marine ecosystems; and finally the increase in carbon dioxide itself, which may threaten ecosystems by altering carbon and nitrogen cycles fundamental to interactions between plants, the atmosphere, and the soil. Global warming may increase turnover in tropical forests, favoring rapidly growing, lightdemanding plants that take up less carbon dioxide, over denser, slower-growing, shade-tolerant plants, thereby accelerating global warming.
Extreme changes in global temperatures resulting in heat waves in temperate regions and cold waves in subtropical areas will also eventually reduce human population. The indirect effects on human health secondary to global climate change, such as crop failure due to unfavorable weather and unavailability of drinking water, will have a heavy toll on human beings, not to mention actual disaster to human lives due to violent calamities such as typhoons, hurricanes, and tornadoes.
Stratosphere ozone depletion may also threaten species, both land and sea. It was the formation of the ozone layer more than 450 million years ago that permitted marine life forms to colonize the land, as it protected them from the lethal effects of ultraviolet radiation. …