Evolutionary constraints could hamper adaptation to climate change in a
forest herb
Abstract
Climate change is increasingly impacting temperate forest ecosystems and
many forest herbs might be unable to track the changing climate due to
dispersal limitations. Forest herbs with a low adaptive capacity are
prone to climate change effects and may benefit from conservation
strategies mitigating dispersal limitations and evolutionary
constraints, such as assisted migration. To assess the vulnerability of
forest herbs to climate change it is key to evaluate their adaptive
potential and to quantify the genetic offset. To this end, we quantified
climate change vulnerability metrics using single nucleotide
polymorphisms (SNPs) along a latitudinal gradient of the
self-incompatible deciduous forest herb Primula elatior. Southern
populations displayed a sharp genetic turnover and a considerable amount
of local adaptation under diversifying selection was discovered.
However, most of the outlier loci could not be linked to climate
variables (71%) and were likely related to other local adaptation
drivers, such as photoperiodism. Furthermore, specific adaptations to
climate extremes, such as drought stress, could not be detected.
Populations in the south of the distribution area had high sensitivity
to climate change due to a low adaptive capacity and a moderate genetic
offset, while central European populations were sensitive due to a high
genetic offset. We conclude that assisted migration with southern source
populations could bear significant risk due to local maladaptation and a
low adaptive capacity. Local admixture and restoration of ecological
connectivity to increase the adaptive capacity and assisted range
expansion to suitable habitat in the north could be advised as potential
mitigation strategies.