Trends in Ecology & Evolution
ReviewHow does ecological disturbance influence genetic diversity?
Section snippets
Why should we consider disturbance as a driver of the distribution of genetic diversity?
Environmental disturbance underpins the dynamics and diversity of many of the world's ecosystems 1, 2. From tsunamis and large wild-land fires to footprints on intertidal mudflats, disturbances drive spatial and temporal variation in the abundance of species and the composition of communities 3, 4, 5. Despite recognition that disturbance has a key role in shaping biodiversity at the species and community levels 2, 6, its role as a driver of the patterns and distribution of genetic diversity
What is ecological disturbance and why is it important?
Ecological disturbances are commonly defined as ‘any relatively discrete event in time that disrupts ecosystem, community, or population structure and changes resources, substrate availability, or the physical environment’ [24]. Disturbances are ubiquitous across the ecosystems of the Earth. They occur from fine spatial scales, such as trampling and wave-induced boulder turnover 25, 26, to large scales, such as landscape-wide fires and tsunamis 27, 28. They can also occur over different
How does disturbance influence genetic diversity through selectively neutral demographic processes?
To set the context for understanding how disturbance shapes the distribution of genetic diversity, it is important to understand the environmental and demographic changes imposed by disturbance. This is because a large fraction of genetic diversity is selectively neutral and, therefore, its distribution is shaped by mutation, migration, and genetic drift [44]. Indeed, even functional genetic variation can be strongly influenced by selectively neutral demographic processes, such as population
How does disturbance influence genetic diversity through natural selection?
Natural selection can potentially respond to several environmental and biotic processes associated with disturbance 68, 69. The effects of climatic instability on the morphology of Galapagos finches (Geospiza spp.) have provided evidence that disturbance events can cause temporal variation in the strength and direction of selection, leading to unpredictable patterns of evolution [70]. However, on particular timescales, disturbance does not necessarily equate to environmental instability because
Can genetic analyses inform understanding of population responses to disturbance?
Our review has highlighted how disturbance influences genetic patterns at the individual and population levels 20, 21, over short and long timescales 81, 82, and by selective and selectively neutral processes 46, 83. We have discussed how the genetic effects of disturbance might be predictable using models framed around key ecological and demographic parameters. However, a major challenge for achieving this, and indeed for predicting the conservation implications of altered disturbance regimes,
Concluding remarks
Disturbance is an important ecological process, but its influence on the distribution of genetic diversity has been largely overlooked. Recent research is beginning to show that disturbance can influence genetic diversity via biological and demographic processes, spatial and temporal variation in habitat suitability, and natural selection and evolution. Key areas for future research (summarised in Box 2) include the evaluation of genetic analyses for understanding demographic and evolutionary
Acknowledgements
Thanks to Sarah Brown and Luciano Beheregaray for discussions on the case studies presented, and to three anonymous reviewers for constructive feedback on the manuscript.
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