When people think of Malesian forests it’s the cavernous Dipterocarps of Borneo that they think of. For those that have also worked in eastern Malesia – it’s a world of cloves – from the lowlands to the mountains.
The wild relatives of cloves, species in the genus Syzygium, are frequently found in a variety of habitats across Malesia. Despite this, knowledge is little. Having tidied up a dataset from the Indonesian forest plot network the unidentified Syzygium species numbered in the hundreds.
Yee Wen Low has pulled together samples from ecologists, systematists and herbaria to build a set of genomes for 182 species and 58 unidentified taxa. Results point to multiple rapid radiations often within the last 1 million years. Recent rapid radiations have been identified before but for Syzygium this involves dispersal across seas to occupy multiple islands/landmasses. Also, super interestingly there is clear evidence of dispersal from east to west in Malesia, against the direction of prevailing sea currents. Could this mean the moreish fruits attract dispersers that render sea currents irrelevant? Whether those dispersers are therefore influential for the make-up of Malesian forests, and it’s carbon stock remains to be seen.
Link to the paper here. The header photo by Gemma Bramley is Syzygium nervosum (det. Yee Wen Low) from the seasonally dry coastal forests of West Sumbawa.