Details of Award
NERC Reference : NE/C510467/1
Harvesting and environmental variability: the causes and consequences of evolution in ecological time.
Grant Award
- Principal Investigator:
- Professor TG Benton, University of Leeds, Inst of Integrative & Comparative Biolog
- Co-Investigator:
- Professor S Piertney, University of Aberdeen, Inst of Biological and Environmental Sci
- Grant held at:
- University of Leeds, Inst of Integrative & Comparative Biolog
- Science Area:
- Terrestrial
- Marine
- Freshwater
- Overall Classification:
- Terrestrial
- ENRIs:
- Natural Resource Management
- Global Change
- Biodiversity
- Science Topics:
- Earth Resources
- Population Ecology
- Population Genetics/Evolution
- Conservation Ecology
- Abstract:
- Recent examples of evolution occurring over the time scales of a few generations Illustrate that biology's traditional separation of timescales into 'evolutionary' (i.e. long term) and 'ecological' (i.e. short term, and current) may be unrealistic. This suggests that to understand, and predict, how populations vary over time we should not just consider 'ecological processes' (such as how births and deaths depend on the number of competitors) but also that the biology may evolve - especially if the environment is changing. The possibility of evolution affecting population dynamics Is perhaps particularly important in harvested populations, such as fisheries, where removal of individuals acts as a strong form of natural selection. In this case, removal of large individuals may lead to evolution resulting in a reduced size at maturity. in turn, smaller adults will tend to lay fewer eggs, which may reduce the population growth rate. This will itself affect the way that the population may recover from over-fishing or respond to a change in the environment due to global warming. The effects of harvesting are, however, more complicated than simply by creating a direct selection pressure due to mortality. Removal of individuals by harvesting means that there are fewer competitors around. This in turn may affect the way that individuals obtain resources like food for growth and reproduction - and therefore affect the 'decisions' they may make as to how big to grow. So, harvesting may create a change in size at maturity through an evolved change or because harvesting changes the amount of competition, which allows the organisms to respond to the environment in a different way. Differentiating a 'plastic' response from an evolved response is easiest by experiment. We are proposing a series of experiments using an animal with a short generation time (so allowing a greater potential for evolution within the project's time scale) and small body size (allowing replicated, population-level experiments). Our model animal is a mite usually found in soil. Our experiments involve allowing populations averaging hundreds of individuals to live freely within their experimental environments (which may have constant food supplies, or food supplies that vary over time). Populations will be subject to harvesting of different types (on adults or on juveniles, with a harvest of a fixed proportion of the population size or any animals above a threshold number). During the time course of the experiment we will monitor: (a) the number of and average sizes of individuals in the population, (b) the genetic differences between populations and (c) changes in the life-history which have an underlying genetic component (by looking at the life-history in a range of 'standard environments'). This experimental design will allow us to describe the rate of evolution and how it vanes with harvesting strategy and the type of environment. It will also allow us to test a range of theoretical predictions about life-history evolution - such as 'does a varying environment lead to individuals having a lower reproductive rate but living, and breeding, for longer?' Following the selection experiment, harvesting will cease and populations will be monitored in both their existing environments and a range of different ones. This will allow us to see whether the population size, its structure - the ratio of adults and juveniles - and its variability over time has been affected by the harvesting. This is important for predicting how harvesting strategies now may affect the populations' ability to survive in an environment that may be changing due to global warming. It will also give us some indication about whether, when harvesting ceases, populations return to the way they ware before harvesting started.
- NERC Reference:
- NE/C510467/1
- Grant Stage:
- Completed
- Scheme:
- Standard Grants Pre FEC
- Grant Status:
- Closed
- Programme:
- Standard Grant
This grant award has a total value of £293,504
FDAB - Financial Details (Award breakdown by headings)
| Total - T&S | Total - Staff | Total - Other Costs | Total - Equipment | Total - Indirect Costs |
|---|---|---|---|---|
| £4,217 | £168,133 | £32,400 | £11,412 | £77,340 |
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