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.

Habit loss, invasive species and climate change have been known as the main drivers of plant extinction. Nevertheless, extinction continues. 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.

In a study published in Trends in Ecology and Evolution, Prof. Richard T. Corlett tried to explore how plant extinctions happened, particularly the relatively small number of plant extinctions in recent years, and the likelihood that many species will face inevitable extinction unless targeted support is provided. He discussed the processes by which plant extinctions occur, including population extirpation following the death of individual plants without replacement, and total extinction of all populations.

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.

“We need targeted interventions for each threatened species and recognition of the shortcomings of current methods of projecting future plant extinctions. Furthermore, with climate change likely to become a dominant factor again before the end of this century, timely conservation measures are essential to preserve plant diversity,” said Richard Corlett.

First published:  7 December 2024