Each species has a thermal niche — a preferred temperature range where suitability is highest. As the landscape warms, most of the grid drifts outside that niche, but cooler refugia (shaded valleys, high elevation, north-facing slopes) can stay suitable longer, so a mobile population that tracks them can persist.
suitability(x) = exp( −((T(x) − T_opt) / σ)² )
T(x,t) = T_base(x) + warming_rate · t − cooling(refugia)
survival ∝ Σ suitability(agent positions)
- Warming rate — how fast background temperature rises across the whole grid each simulated year.
- Migration speed — how quickly individual agents can move toward better (cooler, more suitable) patches.
- Refugia size — the radius of the protected cool patches; larger refugia support more of the population.
- Assisted migration — when enabled, agents are given a helping nudge directly toward the nearest refugia instead of relying only on local gradient-following, mimicking human-assisted translocation.
This mirrors real climate-adaptation strategy: conservationists identify climate refugia (cool microhabitats) and, for species that can't disperse fast enough on their own, physically relocate individuals — assisted migration — to keep populations ahead of the warming curve.