Models of the EVOLTREE modelling platform
The model EcoGene has been developed to study the temporal and spatial dynamics of genetic and demographic processes in a single tree population. It is an individual distance dependent tree model that combines elements of population genetic, demographic, forest growth and management models. Overlapping or discrete generations can be assumed and different processes, as for example, gene flow, mating system, flowering phenology, selection, random drift and intraspecific competition can be implemented.
EcoGene has been developed with the following tasks in mind:
- Analysis of complex population genetic interactions.
- Hypothesis testing of realized genetic systems in tree populations.
- Analysis of the effects of human influence on evolutionary processes in tree populations.
- Deduction of recommendations for sustainable management of genetic resources.
EcoGene provides the opportunity to evaluate and test complex interactions of population genetic and demographic processes. Hereby, the focus is on a very detailed representation of the observed mating system, flowering phenology and pollen- as well as seed-mediated gene flow.
The model ForGEM is a spatially explicit, individual tree model on genetics, ecology and management of forests. It includes detailed descriptions of the life-history of trees on:
- production and dispersal of seeds;
- the establishment, growth and competition for light of seedling cohorts or optionally individual seedlings;
- light interception by individual crowns;
- photosynthesis; (v) growth, including the allocation of the net primary production over the plant components, and the increment of the tree’s height, diameter and stem volume;
- mortality of individual trees.
The model can simulate an understory that consists of grass and herb species that are distributed over, usually 20x20m, grids though grid size is variable. In the soil, water content soil organic matter and nitrogen availability is simulated.
(to run the model, NSM must be installed on your computer - available for Windows only)
The module TranspopRege under CAPSIS4 platform aims at studying the effects of various ecological and genetical processes on the genetic quality of seedlings in contrasted regeneration context (Figure 4 1). Indeed, natural regeneration is a key stage in the life cycle of populations within ecosystems because the demographic structure and genetic make-up of the population is mostly determined at this stage, in particular for long lived organisms such as forest trees.
TranspopRege is an individual-based model similar to a gap model. Space is abstracted as a grid of 50 m x 50 m square cells (or patch), with each patch considered as homogeneous in terms of site, species composition, density and age. Recruitment, growth and mortality are modeled at the individual level. TranspopRege considers only one species, with hermaphroditic individuals. However, as male and female fecundity are described for each individual tree, different sexual determinism can be modeled (i.e. monoecy, dioecy). Each individual tree basically bears dendrometric information (dbh, height, age, location) and genetic information (neutral markers and quantitative traits).
The model VentouG is a multi-species individual-based model similar to a gap model. It's first devoted to the modelling of forest dynamics on the “Mont Ventoux” mountain (southeastern France), but it can be used in more general context and specially for testing scenario.
Evolution of single-species plantations towards mixed forests: beech and fir-beech (Mont-Ventoux)
The VentouG module was developed at INRA in Avignon by the Ecology of Mediterranean Forests Unit (Ph. Dreyfus , C. Pichot).
The model MetaPop simulates the evolution of diversity within a set of populations exchanging genes and undergoing various evolutionary scenarios.