Wallace's Line – Biodiversity of Indonesia
BiologyEcology & EnvironmentAges 17–18
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Ecology & Environment
A map of Indonesia with Wallace's, Weber's and Lydekker's lines. Sort 16 real species (orangutan, Rafflesia, anoa, Komodo dragon, bird-of-paradise and more) into Sunda (Asian), Wallacea (transitional) and Sahul (Australian); lower the sea to ice-age levels to see the Sunda and Sahul shelves become land while the deep water around Wallacea stays; and model forest loss and the effect of protected areas on endemic species.
Lesson: Biogeography of Indonesia: Wallace's and Weber's lines, the Sunda and Sahul shelves, endemic species and threats
What it shows
In the 1850s Alfred Russel Wallace noticed that Bali and Lombok, less than 40 km apart, have very different animals. The map shows his line, Weber's line and Lydekker's line across Indonesia. You sort real species into the Asian Sunda region, transitional Wallacea and the Australian Sahul region using the islands where they live. Lowering the sea by up to 120 m, as in the last ice age, joins the islands on each shelf to a continent, while the deep straits around Wallacea never dry. A third view models forest loss and protected areas.
How to use
In Zones and species, look at the islands shown in orange, then press Sunda, Wallacea or Sahul and Next species. In Ice-age sea level, move the slider or press Start an ice age, and press Record at several levels. In Threats, choose an Island, set the clearing rate and Protected forest, then press Run 50 years.
Parameters you can change
- View Zones and species, Ice-age sea level, Threats to forests
- Sea level lower than today by 0–120 m
- Island Sumatra, Borneo (Kalimantan), Sulawesi, New Guinea
- Unprotected forest cleared each year 0–3 %/year
- Protected forest 0–60 %
Questions to explore
- Why do Bali and Lombok have such different animals although they are less than 40 km apart?
- Which islands joined mainland Asia when the sea was 120 m lower, and which stayed islands?
- How does protecting part of a forest change how many endemic species can survive?
