The road to integrate climate change projections with regional land-use–biodiversity models
Abstract
Current approaches to project spatial biodiversity responses to climate change mainly focus on the direct effects of climate on species while regarding land use and land cover as constant or prescribed by global land‐use scenarios. However, local land‐use decisions are often affected by climate change and biodiversity on top of socioeconomic and policy drivers. To realistically understand and predict climate impacts on biodiversity, it is, therefore, necessary to integrate both direct and indirect effects (via climate‐driven land‐use change) of climate change on biodiversity. In this perspective paper, we outline how biodiversity models could be better integrated with regional, climate‐driven land‐use models. We initially provide a short, non‐exhaustive review of empirical and modelling approaches to land‐use and land‐cover change (LU) and biodiversity (BD) change at regional scales, which forms the base for our perspective about improved integration of LU and BD models. We consider a diversity of approaches, with a special emphasis on mechanistic models. We also look at current levels of integration and at model properties, such as scales, inputs and outputs, to further identify integration challenges and opportunities. We find that LU integration in BD models is more frequent than the other way around and has been achieved at different levels: from overlapping predictions to simultaneously coupled simulations (i.e. bidirectional effects). Of the integrated LU‐BD socio‐ecological models, some studies included climate change effects on LU, but the relative contribution of direct vs. indirect effects of climate change on BD remains a key research challenge. Important research avenues include concerted efforts in harmonizing spatial and temporal resolution, disentangling direct and indirect effects of climate change on biodiversity, explicitly accounting for bidirectional feedbacks, and ultimately feeding socio‐ecological systems back into climate predictions. These avenues can be navigated by matching models, plugins for format and resolution conversion, and increasing the land‐use forecast horizon with adequate uncertainty. Recent developments of coupled models show that such integration is achievable and can lead to novel insights into climate–land use–biodiversity relations. Read the free Plain Language Summary for this article on the Journal blog.
What the paper shows and why it matters
(AI-generated)
Projections of how biodiversity will respond to climate change mostly consider the direct effect of climate on species and keep land use and land cover constant or take them from global land-use scenarios. Yet land use is arguably the strongest current driver of biodiversity change. Local land-use decisions are themselves often affected by climate and by biodiversity, besides socio-economic and policy drivers. The indirect route from climate change through land-use change to biodiversity, and the feedbacks between them, therefore remain relatively unexplored. The problem the paper takes on is how regional land-use and biodiversity models can be connected so that this route is included.
The paper argues that projections of biodiversity under climate change should include both the direct effects of climate and the indirect effects that run through climate-driven land-use change. It holds that this is achievable by coupling regional land-use models with biodiversity models, with an emphasis on mechanistic ones (models that simulate the underlying processes). Its non-exhaustive review finds that land use enters biodiversity models much more often than biodiversity enters land-use models, in four approaches of increasing integration, from overlaying the outputs of both model types to running both models together in one framework that exchanges variables. It finds no study of indirect climate effects with mechanistic models, but regards this as achievable, because mechanistic land-use models that take climate as input have already been coupled to mechanistic biodiversity models. Coupling can change results: in a hypothetical crop–pollinator case, a model in which the two parts influence each other (two-way coupling) predicted larger changes in crop yield and pollinator populations than a version in which information flowed one way only (Synes et al. 2019).
The paper names the steps needed: matching the spatial resolution and file formats of the two model types, longer land-use forecast horizons with explicit uncertainty, biodiversity information as an input to land-use decisions, and eventually feeding the combined outputs back into climate predictions. It holds that coupling can give insights that would not emerge without two-way coupling and, in the long run, allow weighing species numbers, stakeholder profits, carbon balance and temperature together. Limits the paper itself acknowledges: the review is non-exhaustive, and the relative contribution of direct and indirect climate effects is still open.
References
- Synes et al. (2019). Coupled land use and ecological models reveal emergence and feedbacks in socio‐ecological systems. Ecography 42, 814–825. doi:10.1111/ecog.04039