David Waterhouse, Lord Howe Island Board for The Lord Howe Island Signal

The diverse landscape of mountains, valleys, hills, lowlands and sea cliffs of the LHI provide an array of habitat types supporting many distinctive flora. Research Scientists Dr Andrew Denholm and Dr John Porter have been coming to Lord Howe island for many years to study its unique natural values. While it is early days yet, they see promising signs that the removal of rodents is having positive effects for the Islands plants.

Over time, rodents will impact a plant’s ability to reproduce by eating seeds and fruits that otherwise become seedlings and grow to become juvenile and then adult plants. Pants need to maintain a mix of these sizes to avoid extinction. When rodents interrupt this normal process and only adult plants remain, the probability is high that these plants will become extinct.

As an example of improvements, Andrew and John are seeing signs of bigger fruit crops for endemic trees around the Island, more flowering spikes on grasses in the lowlands and more seeds on the ground from the critically endangered Little Mountain Palm in the Cloud Forests. This is good news indicating that, with continued absence of rodents, new generations of plans will be able to establish. This will also help the forest be better prepared for emerging threats like warming temperatures that will see the Cloud Forest retreat to higher elevations.

Rodents also have other impacts beyond eating fruits and seeds. The Cloud Forest is also a centre of endemism for snails and slugs.

John and Andrew observe that the first time they went to the Cloud Forest after the rodents were gone, they saw hundreds of tiny fingernail sized slugs they hadn’t seen in such numbers before. These would have been tasty snacks for rodents but now can play their part in restoring ecosystem function to the Island.

Andrew and John say it’s an exciting time to be coming to the island to see the benefits.

This article appeared in The Lord Howe Island Signal, 30 June 2021.