Flinders University has released a new study that details how one common species of native bee survived centuries of human influence on the world's ecosystems.Flinders University's new paper in Molecular Ecology (DOI 10.1111/mec.16034) examines the link between Homalictus Fijiensis's expansion in Fiji and land clearing and the introduction of weeds and new plants to the environment.James Dorey, a Flinders University researcher, said that while earlier research had linked the recent expansion of the population to warmer climates, our study revealed an interesting and positive response by an endemic species in the face of human changes to the landscape, which began around 1000BC."This species is a super generalist pollinator and pollinates many plant species. It likes to nest on open ground so it appears that one of Fiji's most important bee pollinators has benefited from the human settlement and subsequent clearing of Fiji.The study used phylogenetic analyses to analyze mitochondrial and genetic DNA to examine changes in native bee population in Fiji. The results show that Fiji's bee population grew tremendously from 2000 years ago to 3000 years ago.Dorey claims that there has been no change in the bee population size for Kadavu (a major island) as compared to the main island. This island is home to both human populations and agricultural activities."This is too recent for a warming climate, which occurred about 18,000 000 years ago," said Associate Professor Michael Schwarz, senior author of the paper."We argue instead that the Fijian bee population expansion better coincides the early occupation by the Lapita people of the Pacific islands. This expansion was accelerated by the increasing presence of later Polynesians who altered the landscape with their agricultural practices in Fiji.This research shows how it is possible to infer the effects of early human dispersals even when fossil records do not exist and climate change is a complicating issue.Super-generalist pollinators like the Fijian halictine Bee, Homalictus fijiensis endemic, could have a negative effect on ecosystems by encouraging the growth of exotic crops and introduced weeds.These research techniques can also be applied to other species of animal. Associate Professor Schwarz says that high-resolution population genetic studies like this can be used to distinguish between older and natural events such as climate change or those caused by early human colonization and dispersal."The relative roles of climate and human-induced changes in the environment has been a persistent question in ecosystem studies over the past 60,000 years. There is ongoing debate over the fate of Australia's megafauna. Was it caused by humans, climate change or both?"Those types of questions can be answered if fossil records are very reliable, but what about ecosystems with very poor fossil records?"This paper was the result of nearly a decade-long scientific research into Fiji's biodiversity conducted by SA Museum and Flinders University scientists and students.The research fellow at the SA Museum in World Cultures Dr Stephen Zagala (pictured below) says that the new study provides fascinating insight into how ecosystems have been built during various stages of human migration and settlement.He says that early European explorers, naturalists and scientists were not aware of the fact that large human dispersals have already had a profound impact on the ecology of Pacific islands over millennia. "This study provides important details that help to paint a picture of the Pacific as a highly cultivated area."###The article, Holocene expansion of a tropical honey bee coincides early human colonisation in Fiji (2021), by James B Dorey and Scott VC Groom. DOI: 10.1111/mec.16034
