Data from: Consistent scaling of inbreeding depression in space and time in a house sparrow metapopulation

Inbreeding may increase the extinction risk of small populations. Yet,
studies using modern genomic tools to investigate inbreeding depression in
nature have been limited to single populations, and little is known about
the dynamics of inbreeding depression in subdivided populations over time.
Natural populations often experience different environmental conditions
and differ in demographic history and genetic composition; characteristics
that can affect the severity of inbreeding depression. We utilised
extensive long-term data on more than 3100 individuals from eight islands
in an insular house sparrow metapopulation to examine the generality of
inbreeding effects. Using genomic estimates of realised inbreeding, we
discovered that inbred individuals had lower survival probabilities and
produced fewer recruiting offspring than non-inbred individuals.
Inbreeding depression, measured as the decline in fitness related traits
per unit inbreeding, did not vary appreciably among populations or with
time. As a consequence, populations with more resident inbreeding (due to
their demographic history) paid a higher total fitness cost, evidenced by
a larger variance in fitness explained by inbreeding within these
populations. Our results are in contrast to the idea that effects of
inbreeding generally depend on ecological factors and genetic differences
among populations, and expand the understanding of inbreeding depression
in natural subdivided populations.