Extinction refers to the disappearance of the final individual of a given species. This phenomenon can manifest as local extirpations, where the loss is specific to a particular region, or as global extinctions, where the species is eradicated 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). Researchers have observed that the total number of documented extinctions has escalated to 962 species over the past 250 years.
Habitat loss, invasive species, and climate change are widely recognized as the principal catalysts for plant extinction. However, despite our understanding of these factors, extinctions persist. In order to effectively prevent further extinctions, it is imperative to understand how and why they occur.
In a study published in Trends in Ecology and Evolution, Prof. Richard T. Corlett of Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences sought to understand the mechanisms behind plant extinctions, specifically focusing on the relatively minor number of plant extinctions in recent years.
Initially, the researcher utilized data from phylogenies, as well as fossil and historical records, to examine evidence from past extinctions. The fossil record indicated that climate change was the primary driver of plant extinctions and regional extirpations (the disappearance of a species from a particular area, despite its survival elsewhere) from the Pliocene epoch until recently, when anthropogenic habitat loss took over as the dominant factor.
Subsequently, the researcher analyzed results from revisitation and experimental studies. He discovered that most existing revisitation studies failed to provide information on the immediate causes of plant mortality and recruitment failure. Notably, only a few studies have been designed to identify the drivers of individual species losses.
The researcher believed that there is a pressing need to document the death of marked individuals and the recruitment of new ones, which could be accomplished by integrating more fine-grained studies of the decline and extirpation of isolated populations with large-scale revisitation studies.
Furthermore, extinctions are challenging to demonstrate in plant species. In contrast to extensively studied animal groups, known plant extinctions are markedly fewer. Predictions of massive climate-driven extinctions later this century are plausible.
According to the researcher, at least half of the world's plant species are at risk of extinction. However, present tools fall short in accurately forecasting potential population extinctions. Therefore, it is necessary to use targeted interventions to conserve each endangered species, so as to mitigate threats and protect global biodiversity.
The researcher suggested that a combination of various approaches can be employed; for instance, correlative species distribution models (SDMs) can serve as a measure of exposure to climate change, while mechanistic models or traits can function as predictors of vulnerability.
First published: 7 December 2024
