Genetic monitoring

Genetic monitoring can thus be used to detect changes in species abundance and/or diversity, and has become an important tool in both conservation and livestock management.

The types of molecular markers used to monitor populations are most commonly mitochondrial, microsatellites or single-nucleotide polymorphisms (SNPs), while earlier studies also used allozyme data.

The abundance of cryptic or elusive species that are difficult to monitor can be estimated by collecting non-invasive biological samples in the field (e.g. feathers, scat or fur) and using these to identify individuals through microsatellite or single-nucleotide polymorphism (SNP) genotyping.

For example, DNA from feathers shed by the eastern imperial eagle shows lower cumulative survival over time than seen for other long-lived raptors.

Changes in population ranges have been investigated for Iberian lynx[8] and wolverine,[9] while monitoring of westslope cutthroat trout shows widespread ongoing hybridization with introduced rainbow trout[10] (see cutbow) and Canada lynx-bobcat hybrids have been detected at the southern periphery of the current population range for lynx.

[19] Monitoring of trade and consumption of species of conservation interest can be carried out using molecular amplification and identification of meat or fish obtained from markets.

Monitoring of relative population changes through these metrics has been performed retrospectively for Beringian bison,[24] Galapagos tortoise,[25] houting,[26] Atlantic salmon,[27] northern pike,[28] New Zealand snapper,[29] steelhead trout,[30] greater prairie chicken,[31] Mauritius kestrel[32] and Hector's dolphin[33] and is the subject of many ongoing studies, including Danish and Swedish brown trout populations.

Subjects of such studies include grizzly bears,[3][36][37] cod,[38] red deer,[39] Leopard frogs[40] and Barrel Medic.

Good examples of this are found for New Zealand birds, many species of which were greatly impacted by habitat destruction and the appearance of numerous mammalian predators in the last century and have recently become part of relocation programs that transfer a few ‘founder’ individuals to predator-free offshore “ecological” islands.

This led to a special issue of the journal of Molecular Ecology[49] organized around our understanding of genetic effects in three main categories: (i) habitat disturbance and climate change (ii) exploitation and captive breeding (iii) invasive species and pathogens.