From Field to Forest - Revision history

Xpeka00 at 20:31, 15 January 2014

2014-01-15T20:31:03Z

Xpeka00 at 18:12, 15 January 2014

2014-01-15T18:12:14Z

Xpeka00: /* Results */

2014-01-15T13:34:50Z

‎Results

Xpeka00: /* Method */

2014-01-15T13:29:03Z

‎Method

Xpeka00: /* Method */

2014-01-15T13:18:41Z

‎Method

Xpeka00: Created page with "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 S..."

2014-01-14T22:57:58Z

Created page with "This project simulates the process of natural evolution of a new stable ecosystem on an abandoned field. <div> *'''Project name''': From Field to Forest *'''Class''': 4IT495 S..."

New page

This project simulates the process of natural evolution of a new stable ecosystem on an abandoned field.
<div>
*'''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.<div>
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=

=Model=

=Results=

=Conclusion=

=Code=

@@ Line 32: / Line 32: @@
 The agent characteristics are typical for each type of turtles, however it is randomized in order to refer more accurately to the reality. The characteristics are set as a value of normal distribution with mean value typical for the type of turtle and standard deviation set as a fraction of the typical value (in case of ''rfertility'', ''rsunshine'' and ''max-age'') or as a constant (in case of ''death-ratio'' and ''spread-ratio''). The age is naturally set as 0.
 <div><div>
-The '''characteristics of environment''' are stored for each patch seperately. One patch represents 1m2 of the soil. The characteristics are as follows:
+The '''characteristics of environment''' are stored for each patch seperately. One patch represents 1m2 of the soil. The default size of the field is 20m x 20m. The characteristics are as follows:
 *'''local-fertility''': percentage of the humus in the soil. The local fertility changes over time according to plants living on the soil and rotting dead plants. The initial value is set as randomized user-selected fertility.
 *'''sunshine''': percentage of sunshine that reaches the ground. The initial values is 100 (no shade is produced), but changes over time according to number of trees on the patch and on the neighboring patches and number of bushes on the patch.
@@ Line 77: / Line 77: @@
 *'''spread-ratio''': 27
 *'''max-age''': 150
-The bushes produce shade when older than 10 years. This shade consumes 15% of sunshine reaching the ground on the same patch. Trees older than 20 years produce shade which consumes 25% of sunshine reaching the ground on the same patch and 15% of the sunshine reaching the ground on the neighboring patches.
+The bushes produce shade when older than 10 years. This shade consumes 15% of sunshine reaching the ground on the same patch. Trees older than 20 years produce shade which consumes 25 % of sunshine reaching the ground on the same patch and 15 % of the sunshine reaching the ground on the neighboring patches.
 ===Model dynamics===
@@ Line 89: / Line 89: @@
 ===User interface===
 Before running the simulation the user can adjust the initial fertility of the soil and set the number of yoers for which the simulation will be run. When hitting the '''SETUP''' button, the values are initiated. When hitting the '''GO''' button the simulation starts. The data is recorded and displayed every autumn. However the monitors in the left side of the window (counting each type of turtles) may update continuously. The graphs in the right side of the window show the evolution of numbers of grasses, herbs, bushes and trees, average fertility and sunshine exposure and evolution of nubers of bushes older than 5 years and trees older than 15 years. The latest indicates the maturity of the ecosystem.<div>
-[[Image:Succession_UI.PNG|center|thumb|800px|Picture of the user interface displaying the end of the simulation run. The run lasted 28 years and the initial fertility was set at 20%.]]
+[[Image:Succession_UI.PNG|center|thumb|800px|Picture of the user interface displaying the end of the simulation run. The run lasted 28 years and the initial fertility was set at 20 %.]]
 ==Results==
+During the run of the model it became obvious that with parameters set as described above the balanced ecosystem cannot be estabilished. This can be caused by following isuues:
 ==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. [http://www.jstor.org/discover/10.2307/2460259?uid=41256&uid=3737856&uid=2&uid=3&uid=67&uid=62&uid=41255&uid=5910232&sid=21103247696271]
@@ Line 103: / Line 137: @@
 ==Conclusion==
 ==Code and results files==
-knk
+[[:File:Succession_model.zip]]

@@ Line 7: / Line 7: @@
 *'''Software used:''' NetLogo 5.0.4
-=Problem definition=
+==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.<div>
-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.
+The goal of the project is to simulate the process of secondary succession on an abandoned field. The simulation should answer the question how the initial fertility of the field influences the whole process. 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=
+==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.
 <div>
@@ Line 18: / Line 18: @@
 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=
+==Model==
-=Results=
+====Trees====
-=Citations=
+===Model dynamics===
-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.
+Before the model run is started the initial values are set: global fertility set by user is randomized for each patch. Seeds are generated for some patches (80% of patches hold grass and herbs seeds and 40% of pathces hold bush and tree seeds). When the model run starts, the first spring come and then the seasons follow for user-set number of years.
 <div>
-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.
+*SOJNEKOVA, M. Sekundární sukcese na opuštěných polích pod Děvínem v Pavlovských vrších, 2011, Ms., dip. pr., PřF MU, Brno. [http://is.muni.cz/th/184384/prif_m/?lang=en]
-=Conclusion=
+==Conclusion==
-=Code=
+==Code and results files==

@@ Line 12: / Line 12: @@
 =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. 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. The NetLogo software was used for its simplicity and easy data analysis.
+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.
 =Model=

← Older revision		Revision as of 13:18, 15 January 2014
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	=Method=		=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. 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. The NetLogo software was used for its simplicity and easy data analysis.

	=Model=		=Model=

From Field to Forest - Revision history

Xpeka00 at 20:31, 15 January 2014

Xpeka00 at 18:12, 15 January 2014

Xpeka00: /* Results */

Xpeka00: /* Method */

Xpeka00: /* Method */

Xpeka00: Created page with "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 S..."

Xpeka00: Created page with "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 S..."