I work on ecology related to global conservation. My work includes extinction rates: how to measure them, what drives them and how to reduce them. I have established extinction rates are similar across a wide range of types of organism (for regions with sufficient data) so I suggest they can be monitored using birds and fish in regions where other information is lacking. Habitat destruction is evidently the main driver of extinctions, and I work on the relevance of biomass removal, edge effects, succession and invasive species to habitat restoration. My research helped initiate and drive the rewilding movement. I also work on climate change, renewable energy, and energy policy: what effects does a changing climate have on wildlife, and are the impacts of some climate policies worse? What biological feedbacks could stabilize Earth's atmosphere and climate?