Wade carefully: water parametrization in structural landscape connectivity modeling
Structural connectivity models often include rivers, lakes and shorelines, yet how water is parameterized can strongly influence model outputs. Using simulated and real landscapes, this study tested low, high and neutral water‑resistance values in circuit‑theory models and compared resulting cumulative current patterns. Low water resistance dampened terrestrial current values, while high resistance inflated means and standard deviations, often creating artificial hotspots near water. Neutral resistance produced outputs closest to a null model, minimizing land–water interaction. These results show that water parameterization can complicate interpretation of terrestrial connectivity and that treating water as neutral is most appropriate when models aim to guide land protection or restoration.
Subject Tags
- Lakes
- Rivers
Abstract
Context
Structural connectivity models provide critical insights on how movement potential varies across landscapes and can support decisions on where to prioritize land protection and restoration. Water is a common component of landscape models used to inform conservation strategies, but the impacts of water parameterization on model behavior are poorly understood.
Objectives
We assessed how various parameterization approaches for water bodies, such as rivers, lakes and shorelines, in structural, omnidirectional circuit-theory connectivity models affect patterns in the primary output, cumulative current flow values, in terrestrial grid cells.
Methods
We ran two structural modeling approaches with 10 simulated and six real-world landscapes using three methods for assigning the resistance of water relative to terrestrial resistance values: low, high or neutral values drawn randomly from a distribution informed by the terrestrial resistance grid cells. We then compared the cumulative current outputs from each combination.
Results
The influence of how water was parameterized was consistent across all landscapes. When resistance values for water grid cells were low, the mean values of cumulative current on land were lower, indicating a dampening effect. When water resistances were high, the means and standard deviations of current flow on land were higher, with very high values (a pattern often used to indicate key barriers related to habitat fragmentation and loss) often observed near water. Assigning neutral resistance values to water had the least impact on the current flow across land, relative to a null model.
Conclusions
We demonstrate water parameterization has important impacts on the outputs of terrestrial structural connectivity models that can complicate model interpretation. When the modeler’s intent is to inform land protection or restoration actions in response to human modification, the choice to treat water as neutral minimizes the interaction between water and land grid cells, clarifying output interpretation and use.
Citation
Clark, M., Anderson, J., Anderson, M. G., Hall, K. R., & Poor, E. E. (2025). Wade carefully: water parametrization in structural landscape connectivity modeling. Landscape Ecology, 40(6), 117. https://doi.org/10.1007/s10980-025-02130-z
TNC Authors
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Melissa Clark
Director of Resilience Science
The Nature Conservancy
Email: melissa_clark@tnc.org -
Mark G. Anderson
Director of Conservation Science
The Nature Conservancy -
Kimberly R. Hall
Climate Change Ecologist
The Nature Conservancy
Email: kimberly.hall@tnc.org -
Erin E. Poor
Landscape Ecologist
The Nature Conservancy