HMN 2025: How Overlooked lizards emerge as key seed dispersers in Madagascar’s distinctive forests

After the island of Madagascar drifted away from India 88 million years in the past, isolating it from all different landmasses, its natural world developed in seclusion. As these reworked into crops and animals utterly distinctive to their island, Madagascar grew to become a biodiversity hotspot not like wherever else on Earth.

An essential side of this biodiversity is an ecological course of known as endozoochory, which is when animals eat plant seeds after which poop them out some place else, aiding within the unfold of the crops. Most analysis on endozoochory has centered on the roles of birds and mammals as seed dispersers, however lizards, that are additionally identified to play a major position, have remained largely ignored.

This negligence impressed a group of researchers at Kyoto University to shine a highlight on the standard lizard. Unlike many seed dispersers, lizards should not usually frugivores, animals that thrive on fruit and different fruit-like plant substances akin to nuts and seeds. Fewer than 10% of lizard species have been reported to devour fruits, however those who do can play an essential position, and a few lizards are even identified to behave as major seed dispersers for sure plant species.

“Lizards are under-appreciated as seed dispersers in lots of forest ecosystems, however we hypothesized that they might play a extra essential position throughout a broader vary of areas than beforehand acknowledged,” says corresponding creator Ryobu Fukuyama.

Published in Biotropica, the analysis group centered on three lizard species in a tropical dry forest in Madagascar, conducting behavioral observations, fecal analyses, and seed germination checks. The species, the Malagasy Giant Chameleon, Cuvier’s Madagascar Swift, and the Western Girdled Lizard, are omnivores identified to subsist on fruits, however they’d not but been rigorously studied.

The group’s outcomes revealed that the lizards consumed fruits from over 20 plant species and expelled viable seeds. These plant species have been largely completely different from these usually consumed by the Common Brown Lemur, a principal seed disperser in Madagascar’s forests, indicating the lizards might play a extra essential position than beforehand thought.

Their challenge is not solely about acknowledging the significance of lizards, nevertheless. In latest years, environmental degradation attributable to human actions has taken a toll on Malagasy forests, making some uninhabitable for giant frugivores like lemurs. In distinction, the lizard species noticed on this study can proceed to inhabit these degraded environments. As seed dispersers, these lizards might doubtlessly contribute to forest regeneration, however there are nonetheless many unknowns.

“Although lizards in Madagascar devour fruits from many plant species, different points of their position as seed dispersers, akin to dispersal distances, stay poorly understood,” says Fukuyama. In the long run, the group intends to focus additional on these extra unknowns.