The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) combines the state-of-the-art knowledge about the status and trends of our ecosystems, biodiversity and nature's contributions to people (NCP). In the IPBES regional assessment focusing on Europe and Central Asia (ECA), Chapter 4 assesses the drivers that contribute to change in biodiversity and related nature's contributions to people. In my talk, I will provide overview of the main findings and policy implications related to drivers of change in the IPBES ECA assessment, and discuss the challenges that Chapter 4 authors had when identifying and quantifying driver trends and their effects.
For assessing the drivers of biodiversity change, IPBES adopted the same approach already used in the Millennium Ecosystem Assessment, differentiating between direct drivers and indirect drivers. Direct drivers are those with direct impact on biodiversity and NCP, while indirect drivers influence biodiversity through their impact on direct drivers. While different categorizations of direct and indirect drivers have been proposed over past decade, IPBES assessment distinguished following direct drivers: 1) natural resource extraction; 2) land use change; 3) pollution; 4) climate change, and 5) invasive alien species. Considered indirect drivers were 1) institutional; 2) demographic; 3) scientific & technological; 4) economic, and 5) cultural & religious. Although also natural processes and factors can have impact on biodiversity and NCP, IPBES ECA assessment targets only the anthropogenic drivers, i.e. those that are directly linked to human impact. For example, climate per se is not considered as a driver, but human-induced climate change is assessed as a driver. Where possible and justified, IPBES ECA assessment focused on assessing the trends and effects of anthropogenic drivers during post-industrial time.
Concept of drivers is complicated by the fact that different drivers rarely act in isolation. Not only indirect drivers influence direct drivers, they can have impact other indirect drivers, leading to altered outcome for the direct drivers. Similarly, direct drivers interact with each other and magnify or mitigate both their individual trends as well as their individual and combined effects on biodiversity and NCP. As few of many examples, trends of climate change and land-use change influence the alien species invasions, and effects of climate change are further magnified by land use change. We assessed this complexity by developing causal loop diagrams that indicate the interactions and effects between drivers. However, interactions between drivers and their possible mitigating and enforcing effects are still among the topics that have not received enough attention in the ecological literature and more research is needed to unravel the effects of different drivers acting in concert.