TY - JOUR

T1 - The demographic history of Madagascan micro-endemics: have rare species always been rare?

AU - Helmstetter, Andrew J.

AU - Cable, Stuart

AU - Rakotonasolo, Franck

AU - Rabarijaona, Romer

AU - Rakotoarinivo, Mijoro

AU - Eiserhardt, Wolf L.

AU - Baker, William J.

AU - Papadopulos, Alexander S. T.

PY - 2021/9/29

Y1 - 2021/9/29

N2 - Extinction has increased as human activities impact ecosystems, yet relatively few species have conservation assessments. Novel approaches are needed to highlight threatened species that are currently data-deficient. Many Madagascan plant species have extremely narrow ranges, but this may not have always been the case—it is unclear how the island's diverse flora evolved. To assess this, we generated restriction-site associated DNA sequence data for 10 Madagascan plant species, estimated effective population size (Ne) for each species and compared this to census (Nc) sizes. In each case, Ne was an order of magnitude larger than Nc—signifying rapid, recent population decline. We then estimated species' demographic history, tracking changes in Ne over time. We show that it is possible to predict extinction risk, particularly in the most threatened species. Furthermore, simulations showed that our approach has the power to detect population decline during the Anthropocene. Our analyses reveal that Madagascar's micro-endemics were not always rare, having experienced a rapid decline in their recent history. This casts further uncertainty over the processes that generated Madagascar's exceptional biodiversity. Our approach targets data-deficient species in need of conservation assessment, particularly in regions where human modification of the environment has been rapid.

AB - Extinction has increased as human activities impact ecosystems, yet relatively few species have conservation assessments. Novel approaches are needed to highlight threatened species that are currently data-deficient. Many Madagascan plant species have extremely narrow ranges, but this may not have always been the case—it is unclear how the island's diverse flora evolved. To assess this, we generated restriction-site associated DNA sequence data for 10 Madagascan plant species, estimated effective population size (Ne) for each species and compared this to census (Nc) sizes. In each case, Ne was an order of magnitude larger than Nc—signifying rapid, recent population decline. We then estimated species' demographic history, tracking changes in Ne over time. We show that it is possible to predict extinction risk, particularly in the most threatened species. Furthermore, simulations showed that our approach has the power to detect population decline during the Anthropocene. Our analyses reveal that Madagascar's micro-endemics were not always rare, having experienced a rapid decline in their recent history. This casts further uncertainty over the processes that generated Madagascar's exceptional biodiversity. Our approach targets data-deficient species in need of conservation assessment, particularly in regions where human modification of the environment has been rapid.

KW - Bayesian skyline

KW - conservation genomics

KW - demographic inference

KW - effective population size

U2 - 10.1098/rspb.2021.0957

DO - 10.1098/rspb.2021.0957

M3 - Article

VL - 288

JO - Proceedings of the Royal Society B: Biological Sciences

JF - Proceedings of the Royal Society B: Biological Sciences

SN - 0962-8452

IS - 1959

M1 - 20210957

ER -