Extinction is the loss of the last individual of a species. Extinctions can be local – extirpations – when the loss is from only part of the range, or global, when a species is lost from its entire range.

In the International Union for Conservation of Nature (IUCN) Red List, 126 vascular plants are listed as extinct (EX) and 45 more as extinct in the wild but surviving in cultivation (EW). According to researchers, the total documented extinctions had risen to 962 species over the past 250 years.

Habit loss, invasive species and climate change have been known as the main drivers of plant extinction. Nevertheless, extinction continues. To prevent extinctions, we need to understand how and why they occur..

In a study published in Trends in Ecology and Evolution, Prof. Richard T. Corlett from Xishuangbanna Tropical Botanical Garden (XTBG) tried to explore how plant extinctions happened, particularly the relatively small number of plant extinctions in recent years. 

The researcher first used data from phylogenies, and from the fossil and historical records to review evidence from past extinctions. The fossil record suggested that climate change was the major driver of plant extinctions and regional extirpations (loss of a species from an area while it still survives elsewhere) from the Pliocene until recently, when anthropogenic habitat loss became dominant. 

The researcher then looked at the results from revisitation and experimental studies. He found that most existing revisitation studies lack information on proximate causes of plant mortality and recruitment failure. Few studies have been designed to identify drivers of individual species losses. 

The researcher regarded that there is a need to record the death of marked individuals and the recruitment of new individuals, which can be achieved by combining more fine-scale studies of the decline and extirpation of isolated populations and large-scale revisitation studies.

Moreover, predictions of massive climate-driven extinctions later this century are plausible. Extinctions are hard to prove in plants. In comparison with well-studied animal groups, the known plant extinctions are disproportionately few in terms of percentage.  

According to the researcher, at least half of global plant species face extinction risks.There is a large gap to predict possible population extinctions by using existing tools. 

He suggested that it is necessary to use targeted interventions to conserve each endangered species, so as to mitigate threats and protect global biodiversity. 

It is possible to combine different approaches, using correlative species distribution models (SDMs) as a measure of exposure to climate change and mechanistic models or traits as predictors of vulnerability. 

First published:  7 December 2024