Conservation and enhancement of evolutionary resilience

Management goals may include:

1. Increase population size and overall genetic variation
2. Maintain adaptive potential in target genes/traits,
3. Identify species with little adaptive potential (i.e. low diversity in key ecological traits)
4. Identify and protect evolutionary refugia
5. Increase connectedness and gene flow across environmental gradient
6. Increase adaptability to future environments by translocation

Assisted gene flow

This refers to the introduction of genotypes/individuals that are pre-adapted to new local climates or the increase of the frequency of these genotypes in the existing and affected populations, i.e. within the native species’ range. It helps to increase the recipient’s fitness, its mean survival rate, fecundity, local population size and adaptive capacity of that population. As temperature increases, genes that confer adaptation to warm temperatures are favoured by selection hence increasing their frequency within the population.

In practice

The gene flow between populations that are affected by the same climatic conditions as those now experienced by the target population (e.g., southern populations), and those within the genetic reserve that is being managed, may confer the local population greater evolutionary resilience.

Associated problems

Outbreeding depression, disruption of local adaptation to other environmental factors, or loss of original local lineages. On the other hand, as the target populations are kept in the species native range, ecological risks are lower and relatively predictable.

Genetic rescue

This is an approach used for restoring genetic diversity specifically in small, isolated and frequently inbred populations (hence, low fitness). It differs from assisted gene flow and from targeted gene flow by the fact that any individual from elsewhere can be translocated and the increase in genetic variation can go in any direction.

Genetic engineering techniques

These involve the alteration of the genetic structure of an organism by either removing or introducing specific genes (but preventing undesirable genes) from a different organism within or between species. Genome editing is one technique in which DNA is inserted, deleted, modified or replaced in a specific site of the genome of a living organism. Within this context, genetic engineering would aim at increasing the population’s fitness.