Socio-economic inequality is an important factor to consider when predicting rates of human-induced biodiversity loss, according to new findings by a group of researchers from McGill University in Canada. The Canadian team of scientists has analyzed data from 50 countries and compared different socio-economic models’ ability to predict biodiversity loss, measured as the proportion of threatened plant and vertebrate species (animals with a backbone). They have published their results in Conservation Biology, in a paper entitled “A Cross-National Analysis of How Economic Inequality Predicts Biodiversity Loss”.

– Our results confirm that economic inequality is an important predictor of biodiversity loss, says Professor Garry Peterson one of the scientists behind the new study.
Statistical comparisons revealed that ‘economic footprint’ (the size of the economy relative to the country area), together with ‘income inequality’, was the best predictors of the proportion of threatened species.

The new study is an extension of previous work from McGill University, which was published in PLoS ONE in 2007 (see SDU 2/2007). The new study evaluates a broader range of competing measures/models tested across a greater number of countries. The authors assessed the status of biodiversity in the studied countries by the proportion of plant and vertebrate species that were defined as threatened in 2007 by the International Union for Conservation of Nature (IUCN) or the World Resources Institute (EarthTrends database).

Complex relationships
One aspect of the study that stands out as particularly interesting is that human population density is not a good indicator of the environmental impact of a society. In the past, many scientists thought that human population size was the main driver of biodiversity loss. Recently other  researchers demonstrated that the size of the economy provided a better explanation of environmental impact.

– Our studies show that the structure of the economy, how unequal an society is, is also an important driver of biodiversity loss, Garry Peterson continues.

Considering the huge importance of biodiversity to human well-being and the irreversibility of its loss, many now see the ongoing extinction of species as one of the most important environmental threats today. We all benefit from the diversity of plants and animals for medicines, food, fibres, and other ecosystem services, such as climate stabilisation, water cleansing, crop pollination and flood control. Moreover, several recent studies have concluded that the major beneficiaries are the billions of the world's poor.

(Por Fredrik Moberg, Albaeco, 15/04/2009)