Human activities are causing the fragmentation of the Brazilian Atlantic rain forest. One result is that toucans have become extinct or nearly extinct in some of the forest fragments. Does the absence of toucans affect the forest? Toucans can eat fruits with large seeds because their large bills can open wide. Most other birds in the same forest can only eat small seeds. Ecologist Mauro Galetti and his colleagues measured the seed sizes of palms in forest fragments with and without toucans. The graphs show two of the forest populations they studied. What is the take-home message of the data?

Verified step by step guidance

1. Examine the graphs to understand the distribution of seed sizes in forests with and without toucans.
2. Note that in forests with toucans, there is a wider range of seed sizes, including larger seeds (10-14 mm).
3. Observe that in forests without toucans, the seed sizes are more uniform and smaller (8-10 mm).
4. Conclude that the absence of toucans affects the seed size distribution, leading to a predominance of smaller seeds.
5. Understand that toucans play a crucial role in dispersing larger seeds, which affects the plant diversity and structure of the forest.