Understanding the effects of global change on biodiversity

The continued growth of human populations and of per capita consumption have resulted in unsustainable exploitation of Earth’s biological diversity, exacerbated by climate change, ocean acidification, and other anthropogenic environmental impacts. We have argued that effective conservation of biodiversity is essential for human survival and the maintenance of ecosystem processes¹. Despite some conservation successes (especially at local scales) and increasing public and government interest in living sustainably, biodiversity continues to decline. Moving beyond 2010, successful conservation approaches need to be reinforced and adequately financed. In addition, however, more radical changes are required that recognize biodiversity as a global public good, that integrate biodiversity conservation into policies and decision frameworks for resource production and consumption, and that focus on wider institutional and societal changes to enable more effective implementation of policy¹.

 

We have used landsat satellite imagery to reveal the devastating impacts of government subsidies on deforestation in lowland Chile, where native forests were rapidly replaced by plantations in the 1990s². Proximity to roads and slope determined which forests were lost³. The remnant fragments were severely altered as a result of isolation⁴. In collaboration with Rob Ewers we have developed approaches to quantify the landscale-level effect of fragmentation^5,6, scaling up from measure of biodiversity change made on the ground.

 

We have also explored the consequences of invasion of a hawkweed into New Zealand Nothofagus forests. The hawkweed has invaded ~80% of the study region within ~50 years of arrival, with invasion occurring mostly in sites with high plant diversity (i.e. so much for diverse communities repelling invaders!). We show that invasion is facilitated by diverse communities because the right kind of mycorrhizas for hawkweed are present in the soil ⁷. The herb is a particularly successful invader because it establishes well in treefall gaps then persists even after the forest closes over again⁸.