Each of the 8 candidate species grows according to competitive logistic (Lotka-Volterra) dynamics: its population expands toward a shared carrying capacity that is reduced by every individual of every other species present, weighted by a competition coefficient β. The bar chart on the right shows each species' current population; the strip below it scrolls the community's total population and Shannon diversity over time so you can watch how they respond as you drag the sliders.
dN_i/dt = r_i · N_i · (1 − (N_i + β·Σ_{j≠i} N_j) / K_i)
K_i = K_base · habitatHealth
Shannon diversity: H' = −Σ p_i·ln(p_i), p_i = N_i / ΣN
Pielou evenness: E = H' / ln(S_active)
- Species richness (S) — how many candidate species can colonise the habitat; fewer species means less possible diversity even if each thrives.
- Habitat health — scales the shared carrying capacity K_i; degrading it forces stronger competition and pushes weaker species toward local extinction.
- Disturbance rate — sets the per-second probability and severity of random population crashes (e.g. drought, fire, disease), continuously stressing the community.
- Extinction event — immediately culls one randomly chosen species by 70%, simulating an acute shock such as habitat clearance.
This mirrors why conservationists track both richness (species count) and evenness (how balanced their abundances are): a habitat with ten species where one dominates 95% of individuals is far less resilient than one where abundance is spread evenly — exactly what the Shannon index and evenness score quantify.