Biodiversity depends jointly on habitat (forest cover) and environmental quality (pollution). Losing either one degrades the ecosystem, and their effects compound multiplicatively rather than simply adding up.
dF/dt = −k_def·d + k_grow·(1−F) (forest cover)
dP/dt = k_pol·p − k_clean·(1−p) (pollution level)
B = F^0.7 · (1 − P)^0.9 (biodiversity index)
Animals ∝ B · N_max
- Deforestation rate — how aggressively forest is cleared each year (offset slightly by natural regrowth).
- Pollution level — target pollution level the environment drifts toward; drives visible smog particle density.
- Conservation effort — reforestation and clean-up investment that pulls forest cover up and pollution down over time.
- Sim speed — years simulated per real second.
This mirrors real ecological monitoring: satellite-tracked forest cover and air-quality indices are combined into composite biodiversity/ecosystem-health scores used by conservation agencies to prioritise intervention.