deranged

[R PACKAGE] Modeling software for mechanistic species range simulations.

Overview

To understand how species' geographic ranges shift in response to forces like climate change, we need to model the underlying mechanistic processes like population demography and dispersal. The R software library deranged (for “DEmographic RANGE modeling with Dispersal”) is a modeling package I developed that provides a flexible set of open source tools for efficiently simulating species range dynamics for a wide range of different applications. This software also underpins parts of my own empirical research focusing on climate impacts on forests.

Key Features

• Demographic module using a Markov population matrix model to simulate local age- or stage-based population dynamics as a function of environmental variation
• Dispersal module simulating movement among grid cells with customizable dispersal kernels
• Environment integration allowing local population patterns to respond to both spatial and temporal environmental variation
• Stochastic and deterministic options for discrete stochastic dynamics and continuous deterministic dynamics
• High-performance implementation with core functions written in C++ for computational efficiency
• Visualization tools for analyzing and presenting simulation results

The package provides a framework where demographic rates (survival, growth, reproduction) can vary by population density and environmental conditions, and dispersal can be simulated using various probability distributions and range boundary behaviors.

Applications

The deranged package is useful for:

• Simulating climate change impacts on species distributions
• Modeling invasive species spread across landscapes
• Investigating source-sink dynamics in heterogeneous environments
• Testing hypotheses about factors limiting species ranges
• Assessing management interventions like assisted migration
• Exploring evolutionary adaptation across space and time

Resources

The project lives here on GitHub. Development is ongoing, and additional features and API changes will be added over time.

This project is part of Barracuda, an NSF-funded research program focused on modeling landscape adaptation to climate change.