Does Evolutionary History Correlate with Contemporary Extinction Risk by Influencing Range Size Dynamics?

Area of Science:

• Ecology
• Evolutionary Biology
• Botany

Background:

• Extinction risk is a significant threat to plant biodiversity.
• Factors predicting extinction across the plant Tree of Life (ToL) are not well understood.
• Taxon age has been proposed as a predictor of extinction, but evidence is equivocal.

Purpose of the Study:

• To investigate the correlations between taxon age, diversification rates, range size, and contemporary extinction risk in plants.
• To determine if range size mediates the relationship between age and extinction risk.

Main Methods:

• Analysis of 639 plant genera (8,937 species) across the plant Tree of Life.
• Statistical modeling to assess relationships between age, diversification, range size, and extinction threat.
• Case studies in conifers and palms to examine range size mediation.

Main Results:

• Younger and faster-diversifying genera exhibited a higher proportion of threatened species.
• In conifers, older species had smaller potential range sizes, correlating with higher extinction risk.
• Range size, not age itself, was the primary factor influencing extinction risk in conifers; age and extinction were not directly or indirectly correlated in palms.

Conclusions:

• Range size dynamics are crucial in explaining varied extinction risk patterns across plant groups.
• Conservation strategies should consider range size and its historical dynamics.
• Understanding these factors is vital for effective plant biodiversity conservation efforts.