Quokka Population Dynamics (2D)

This 2D companion trades the orbiting beach scene of the 3D original for the real story behind Rottnest Island's quokkas: a small, isolated marsupial population with essentially no natural land predators, whose numbers are instead governed by vegetation, fresh water and human disturbance. A logistic-growth model — dP/dt = r·P·(1 − P/K) — tracks the colony against a carrying capacity that itself depends on habitat condition: vegetation regrows logistically and is grazed down daily, water is replenished by rainfall that shrinks under drought, and pushing tourist disturbance above its 1.0× baseline trims available shelter and adds a small extra daily mortality term for heat stress and vehicle strikes near visitor areas — a direct nod to the documented cost of crowding and over-feeding at real quokka-selfie hotspots. Every quokka drawn on the beach is sampled from the live population count, so the scene visibly thins or fills out as the sliders push the colony past its resource limits.