Modeling connectivity is… complicated (to say the least).
Circuit-theory and least-cost path, habitat and resistance layers, model validation and spatial resolution – the details can easily drown out the big picture. At its core, connectivity modeling is a useful tool for understanding how individuals move through fragmented landscapes, and for making decisions that achieve management and conservation goals across land- and seascapes.
Riordan‐Short, E., Pither, R. and Pither, J. 2023. Four steps to strengthen connectivity modeling. Ecography. DOI: 10.1111/ecog.06766
Fortunately, there is plenty of guidance to make connectivity modeling easier and more effective, such as:
- which connectivity metrics to use for conservation planning and monitoring
- how to incorporate social networks for effective connectivity
- methods to plan for climate-wise connectivity
- which connectivity tools are most useful for different scenarios
Adding to this guidance is a recent study that provides guidance by suggesting four steps to improve the clarity and reliability of connectivity modeling:
- describe the type of connectivity being modeled, such as daily foraging, seasonal migrations, dispersal/genetic, or range shifts;
- conduct a sensitivity and uncertainty analysis on model parameters to better understand where unknowns are;
- validate model inputs and especially model outputs, preferably with as much independent data as possible; and
- make (non-sensitive) data and code openly available to improve transparency and reproducibility of connectivity models.
The study includes a review of circuit theory-based connectivity publications on terrestrial mammals over the past decade. It shows that out of almost 200 studies, 60% did not make clear the type of connectivity they intended to model. Only 18% conducted some form of sensitivity and uncertainty analysis (although this is becoming more common over time). Almost half included no validation step at all for either model input layers or model output layers. Of those that did perform validation, just 1/5 used fully independent data. Only a handful of studies provided access to raw data or the code necessary to repeat the analysis.
Included with the recommendations and review is a generalized flowchart and checklist of basic information to help guide practitioners. This provides a short summary and visual guide for making decisions along each step of the way in modeling.
As connectivity moves toward the spotlight with efforts such as the global 30×30 initiative and the U.S. Infrastructure Investment and Jobs Act, it’s increasingly important that connectivity modeling be done well. Taking steps to standardize methods and results can improve both the rigor and usefulness of models. This makes the science and management of connectivity more reliable, leading to better conservation outcomes all around.
Related Posts
Reviewing four decades of fragmentation metrics
A review of fragmentation metrics since 1990 shows how methodologies have shifted over time, and what work still needs to be done to ensure transferable and ecologically grounded research.
A practical framework for climate-informed landscape planning
Climate change refugia and landscape connectivity can be systematically incorporated into planning through a practical five-step framework.
Practical guidance for climate-smart planning
A recent climate-informed approach to landscape planning outlines a five-step process that integrates climate change exposure and refugia information to strengthen conservation and management decisions.
