From Field to Forest
This project simulates the process of natural evolution of a new stable ecosystem on an abandoned field.
- Project name: From Field to Forest
- Class: 4IT495 Simulation of Systems (WS 2013/2014)
- Author: Alice Peková
- Model type: Agent-based simulation
- Software used: NetLogo 5.0.4
Problem definition
When a field is abandoned, it takes aproximately 150 years before it turns into a natural forest. This process called secondary succession was firstly described by F. A. Clements in 1916. In this paper a Tolearance Model of Succession is used as presented in the article Mechanisms of Succession in Natural Communities and Their Role in Community Stability and Organization written by Joseph H. Connell and Ralph O. Slatyer, which is typical for abandoned field behavior. This model of succession suggests that the change in plant species dominance over time is caused by competition for resources. Later species are able to tolerate lower resource levels due to competition and can grow to maturity in the presence of early species, eventually out competing them.The sources used are soil fertility and sunshine available. The model is set in central-european climate, which implies that the ecosystem reached with the succession should be a mainly deciduous forest with oaks prevailing.
Method
The succession is a complex process with number of mutual dependancies. Two essential viewpoints can be taken. The focus can be put either on the feedbacks between various plants, soil and the envirnment, or on the individual behavior of each plant in the changing environment.
The results of feedback loop analysis of the process of secondary succession was presented for example in the article Feedback dynamics analysis of secondary successional transients in ecosystems written by Luis T. Gutierrey and Willard R. Fey.
I have chosen the latter approach, as there are many possibilities of individual plant's reactions. For this approach an agent-based simulation is appropriate where each plant is percieved as an agent with specific requirements and behavior. The NetLogo software was used for its simplicity and easy data analysis.
Model
Results
Citations
CONNELL, Joseph H.; SLATYER, Ralph O. Mechanisms of succession in natural communities and their role in community stability and organization. American naturalist, 1977, 1119-1144.
GUTIERREZ, Luis T.; FEY, Willard R. Feedback dynamics analysis of secondary successional transients in ecosystems. Proceedings of the National Academy of Sciences, 1975, 72.7: 2733-2737.
