LUBERON 2: the demo-genetic model showing how silviculture reduces density-dependent natural selection in tree populations
Evolutionary processes benefit and must be nurtured in biological production systems and conservation efforts. Creating evolutionary-oriented strategies requires an understanding of the evolutionary implications of management across temporal scales. Aiming to investigate the connections and feedback between tree thinning, genetic evolution and stand dynamics, a group of researchers at INRAE (France) developed LUBERON2: an individual-based demo-genetic model.
LUBERON2 has been developed to explore the combined effects of genetic diversity, management scenarios and disturbance regimes on tree stand performance and evolution. The evolutionary rates predicted by this model fit in the range of observed values in wild plant and animal populations. The comparison among silviculture and disturbance scenarios was qualitatively robust to assumptions on the genetic architecture of the variable traits. As expected, within each rotation cycle, forest stands could have rapid response to selection through changes in genotypic frequencies rather than gene diversity, resulting in limited long-term erosion of the variance across generations.
In many forests, fisheries and other semi-natural ecosystems, human interventions interfere with natural evolutionary processes. Previous studies have provided evidence of direct or indirect anthropogenic selection in such systems. Here, by simulating scenarios of random tree thinning, i.e. without anthropogenic selection, researchers show that the main impact of random tree thinning is to partially substitute natural selection by anthropogenic selection (non-selective in this case), through two mechanisms. First, by modifying stand structure throughout the forest cycle, the forester reduces the intensity of density-dependent natural selection processes. Secondly, the composition of the breeding population results from the forester's choice and not only from natural selection. Therefore, even supposedly "neutral" population management has non-neutral evolutionary consequences.
Godineau, C., Fririon, V., Beudez, N., de Coligny, F., Courbet, F., Ligot, G., Oddou-Muratorio, S., Sanchez, L., Lefèvre, F. (2023). A demo-genetic model shows how silviculture reduces natural density-dependent selection in tree populations. Evolutionary Applications, https://doi.org/10.1111/eva.13606
The model can be used for research, training and education or demonstration with a user-friendly graphical mode. More information at: https://capsis.cirad.fr/capsis/help_en/luberon2
