Can Macroevolution Inform Contemporary Extinction Risk?

TL;DR

This paper explores whether macroevolutionary patterns can help identify species at risk of extinction today.

Contribution

It clarifies that only past extinction rates reliably predict current extinction risk, while other macroevolutionary indicators need more validation.

Findings

Past extinction rates correlate with current extinction risk due to shared traits.

Diversification and niche evolution rates are not generally reliable predictors.

Validation of assumptions is needed before using macroevolutionary indicators in conservation.

Abstract

Current global changes are driving many species towards extinction, making the early detection of threatened species a priority for efficient conservation actions. However, the threat status of many species remains unknown due to insufficient data on updated distributions, population sizes and population trends and using ecological indicator traits, such as range size, is not always straightforward. Recent advances suggest that macroevolutionary indicators (rates of extinction, net diversification or niche evolution) could provide novel insights into extinction risk based on the assumption that macroevolutionary rates can serve as proxies for extinction‐promoting traits (small range size, narrow niche breadth or low evolutionary potential). However, this assumption has not yet been sufficiently investigated to use this approach. Here, we assess current understanding of the assumptions underlying the relationship between macroevolutionary indices and contemporary extinction risk. We find that only past extinction rates can be reliable predictors of current extinction risk due to their correlation with inherited extinction‐promoting traits. Assumptions underlying relationships between current extinction risk and diversification and niche evolution rates vary by taxon or ecological conditions, and require further investigation through targeted studies. When underlying assumptions are validated, macroevolutionary indicators could be promising tools complementing trait‐based approaches in identifying inherent extinction risk.

We investigate the underlying assumptions of the idea that macroevolutionary indicators for large groups of species, such as rates of extinction, diversification or niche evolution, can inform species' current and future extinction risk status. We find that only past extinction rates can be reliable predictors of current extinction risk as the same traits that are related to past extinctions are also related to current extinction risk. Diversification and niche evolution rates, on the other hand, are currently unlikely to be generally useful predictors because underlying assumptions were only met in specific cases (e.g., restricted geographic space) or hard evidence is only starting to emerge. Before using macroevolutionary indicators to assess species' intrinsic vulnerability or guide data collection priorities, future studies must first verify the validity of underlying assumptions, recognising that final conservation decisions will require additional supporting data.

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