Agricultural Expansion: Still a Cause for Concern

Recently I have been reading some interesting articles on global biodiversity scenarios for my ‘Global Environmental Change’ module (the module for which I started this blog). As I have been discussing fairly specific topics in my last few posts I thought this was a perfect opportunity to get my head out of the hives (see previous posts if you’re struggling with that pun…) and talk more generally about environmental change.

By now most of us realise that with environmental changes come changes to biodiversity levels. In a paper written by Henrique Pereira and his colleagues habitat loss is picked out as a key metric for biodiversity change, with land-use a dominant driver of change in terrestrial systems. Straight away my ears pricked up and the light bulb appeared over my head…agricultural expansion!

Agriculture is a key land-use across the globe, and throughout history it has expanded to enable growing world populations to meet their food production demands. Quantitative scenarios still hold the conversion of natural and semi-natural habitats into agricultural landscapes as a substantial contributor to future global biodiversity changes. As conversion can often lead to habitat loss and degradation it is hardly surprising agriculture plays such a large role in global environmental change.

Pereira and his colleagues highlighted conversion of forest to agricultural systems as the most important habitat change affecting global biodiversity levels, with particular losses occurring in the tropics. In the western world such conversions are no longer extensive, and are in fact in reverse due to overall gains in forest. However, these gains cannot directly compensate for forest losses in temperate regions in terms of biodiversity, as the forest habitats of the northern hemisphere support comparatively lower levels of biodiversity than those in tropical and subtropical regions. This is reflected in the fact that models of global biodiversity scenarios still suggest species declines in terrestrial systems.

Deforestation, to make space for agriculture, in Brazil (source: forestjustice.org)

One issue I am taking from this is that no matter what regulation changes are taken in the developed world to improve agricultural practices in terms of environmental sensitivity, or even those to restrict agricultural intensification and expansion, global biodiversity levels are still facing a future of decline. Agriculture is a global phenomenon, with global impacts, and hence any attempts to drive improvements in the health (and future) of the natural environment through changes to agriculture must be implemented on a global scale. This is where geopolitics becomes hugely relevant, but that is more the realm of a human geographer!