Data from: Past volcanic activity predisposes an endemic threatened seabird to negative anthropogenic impacts

Humans are regularly cited as the main driver of current biodiversity
extinction, but the impact of historic volcanic activity is often
overlooked. Pre-human evidence of wildlife abundance and diversity are
essential for disentangling anthropogenic impacts from natural events.
Réunion Island, with its intense and well-documented volcanic activity,
endemic biodiversity, long history of isolation and recent human
colonization, provides an opportunity to disentangle these processes. We
track past demographic changes of a critically endangered seabird, the
Mascarene petrel Pseudobulweria aterrima, using genome-wide SNPs.
Coalescent modeling suggested that a large ancestral population underwent
a substantial population decline in two distinct phases, ca. 125,000 and
37,000 years ago, coinciding with periods of major eruptions of Piton des
Neiges. Subsequently, the ancestral population was fragmented into the two
known colonies, ca. 1,500 years ago, following eruptions of Piton de la
Fournaise. In the last century, both colonies declined significantly due
to anthropogenic activities, and although the species was initially
considered extinct, it was rediscovered in the 1970s. Our findings suggest
that the current conservation status of wildlife on volcanic islands
should be firstly assessed as a legacy of historic volcanic activity, and
thereafter by the increasing anthropogenic impacts, which may ultimately
drive species towards extinction.