Data from: The power of evolutionary rescue is constrained by genetic load

Extinction risk of small isolated populations in changing environments can
be reduced by rapid adaptation and subsequent growth to larger, less
vulnerable sizes. Whether this process, called evolutionary rescue, is
able to reduce extinction risk and sustain population growth over multiple
generations is largely unknown. To understand the consequences of adaptive
evolution as well as maladaptive processes in small isolated populations,
we subjected experimental Tribolium castaneum populations founded with 10
or 40 individuals to novel environments, one more favorable, and one
resource poor, and either allowed evolution, or constrained it by
replacing individuals one-for-one each generation from a non-adapting
large population to minimize both adaptive and non-adaptive evolutionary
processes. Replacement individuals spent one generation in the target
novel environment before use to standardize effects due to the parental
environment. After 8 generations we mixed a subset of surviving
populations to facilitate admixture, allowing us to estimate drift load by
comparing performance of mixed to unmixed groups. Evolving populations had
reduced extinction rates, and increased population sizes in the first four
to five generations compared to populations where evolution was
constrained. Performance of evolving populations subsequently declined.
Admixture restored their performance, indicating high drift load that may
have overwhelmed the beneficial effects of adaptation in evolving
populations. Our results indicate that evolution may quickly reduce
extinction risk and increase population sizes, but suggest that relying
solely on adaptation from standing genetic variation may not provide
long-term benefits to small isolated populations of diploid sexual
species, and that active management facilitating gene flow may be
necessary for longer-term persistence.