The arrival of humans on the islands of the South Pacific has been associated with a reduction in the diversity of plant species in the region for thousands of years, according to international researchers, including New Zealanders and Australians.
The team analyzed the trends in plant species diversity over the last 5,000 years using fossil pollen records from 13 islands in the region, and says it has found a trend toward increasing similarity among species observed over time.
According to the researchers, this greater similarity is linked to human colonization, with greater diversity in places that probably remained undisturbed for longer, and similar patterns of diversity observed on islands that were colonized in similar time periods.
“This study presents an analysis showing that the vegetation of the South Pacific islands has become more homogeneous in the last 5,000 years. Some narratives point to biotic homogenization as largely a contemporary issue, exacerbated by the expansion of inter-island trade, which, in turn, increases the opportunities for the dispersal of plant taxa,” the researchers emphasise.
“Our analysis, however,” add the specialists, “indicates that initial human colonization was probably the main driver of floristic homogenization, and that future trends in floristic similarity will depend on the levels of ongoing ecosystem modification by humans, the rates of introduction of non-native species, and the rates of extinctions and extirpations.”
“This study highlights the need for long, standardized paleoecological records that can be integrated with modern ecological observations to fully understand and effectively manage modern island ecosystems,” they conclude.
