Assessing Impacts of Land use and climate change on Ecosystem services, in Ile de France using InVEST models.

Models simulating the impact of land-use policies on Ecosystem Services (ES) are valuable tools to inform decision-makers. They indeed help taking into account how the goods and benefits that ecosystems provide to humans may vary due to public policies. The present study was conducted to assess the impacts of Climate and Land Use Change on Ecosystem Services, to deepen the understanding of their respective relevance and joint effects and to investigate whether currently available and widely used InVEST’s models are capable of grasping not only the implications of Land Use Change (LUC), but also the ones of Climate Change (CC) on Ecosystem Services. The models used were created by InVEST, a suite of spatially-explicit models that enables decision makers to assess quantified tradeoffs associated with alternative management choices. An historical overview of the evolution of ecosystem services was delineated and future projections were included. The study area is Île de France and the time interval that was considered spans from 1999 to 2050. For the past years, historical data on climate and land use were used, while, to have a reliable projection of ecosystem services in 2050, various scenarios were taken into account, considering different levels of intensity, for both urbanisation and climate indicators. Here we show how future scenarios of climate and urbanisation interact and impact various ecosystem services (Seasonal Water Yield, Nutrient Delivery Ratio, Urban Heat Island, Urban Flood risk). The research shows for each ES studied, whether the impact of CC is greater or lesser that the one of LUC, and how significant is the variation of ES between now and the future scenarios. In a broader sense, climate change and urbanisation cannot be ignored as their joint impact can substantially change life standards of citizens. It is therefore imperative to rightly inform policymakers on the implications of Climate Change and Land Use Change, in order to take appropriate action while also increasing the focus on bettering the technology used for such evaluations.