Both high agricultural productivity and human health depend on the activity of a diverse natural biota and although efforts to curb the loss of biodiversity have intensified in recent years, they have not kept pace with the growing encroachment of human activities. An example of the economic benefits described is, $20 billion year spent worldwide on pesticides, but parasites and predators existing in natural ecosystems provide an estimated five to ten times this amount of the pest control, and without the existence of natural enemies, crop losses by pests in agriculture and forestry would be catastrophic and costs of chemical pest controls would escalate enormously.
Maintaining biodiversity is essential for organic waste disposal, soil formation, biological nitrogen fixation, crop and livestock genetics, biological pest control, plant pollination, and pharmaceutical development. The authors estimate that in the United States, biodiversity provides a total of $319 billion dollars in annual benefits and $2,928 billion in annual benefits worldwide. The paper describes many of the individual factors that went into calculating this number.
Amidst continuing loss of natural habitat and biodiversity, it is necessary to examine the benefit:cost ratio of investments in habitat conservation. Evidence has been accumulating that shows habitat conservation generates more economic benefits than does habitat conversion. The authors estimate that the overall benefit:cost ratio of an effective global program for the conservation of remaining wild nature is at least 100:1.
A loss of biodiversity leads to an increase in the spread of disease, which researchers speculate is because some species are better at buffering disease transmission. The study examines 12 diseases from different ecosystems worldwide, including Lyme disease. In eastern North America, the white-footed mouse, which is abundant in low-diversity forest fragments is associated with high levels of lyme disease transmission, while Virginia opossums, which are absent from many low-diversity forest fragments and degraded forests, are poor hosts for the pathogen and kill the vast majority the ticks which spread the disease that attempt to feed on them.
Biodiversity conservation and poverty reduction are two global challenges that are inextricably linked, but because biodiversity is generally a public good, it is under-valued, or not valued at all, in national economies. This paper focuses on the question “which groups of the (differentiated) poor depend, in which types of ways, on different elements of biological diversity?” It focuses on biodiversity as a means of subsistence and income to the poor and biodiversity as insurance to prevent the poor from falling even deeper into poverty.