Savanna Wet and Dry Seasons: Rainfall, Grass, Herds and Predators in 3D

Day 1

Savanna wet and dry seasons

Loading terrain, animals and trees...

Guided scenario

Sandbox controls

Annual rainfall

Sets the size of the wet season. Under about 400 mm a savanna turns marginal; above 1,200 mm it is lush.

Predators (live)

Moving this slider adds or removes animals right now; afterwards the numbers follow the model.

Active waterholes

Seasonal migration

On: herds drift out of the 72-ha window when grass browns and come back when it greens (emigration and immigration terms).

Day and night cycle

Time of day

Live readouts

Tap an animal in the 3D view to select it. Numbered circles are annotated hotspots: tap one to read about it and fly there.

Time series

Grass (kg DM/ha)Herbivores (animals)Predators (x10, animals)Rain (mm/day)

Phase plane: predators vs herbivores

The trajectory spirals around the coexistence point. Dashed lines are the nullclines (where one population stops changing) at the current grass and water, so they move with the seasons.

Greenness through the year (NDVI-like)

Event counters

The model in equations

The science

Independent numerical checks

Parameter table

Selected animal

Tap an animal in the 3D view.