"Our team mission is to gain an understanding of mathematical modeling of biological systems as well as an understanding of actual ecological processes occuring in the Rainforest.  We will apply this knowledge, along with useful information from other groups, to create two models of specific examples of interactions in the Rainforest.  We will use these models to make recommendations on some vital parameters necessary to maintain ecological equilibrium."

The following contents are what I have been researching chronologically.

Sept 23, 2002

       Our group does not assign specific topics to anyone yet, we decided to look for some interesting information about system interaction. I searched the website of The Woods Hole Research Center -WHRC, USA. I found some examples of system interaction. For example, leafcutting ants stimulate forest growth, mulches from common weeds act as excellent fertilizers, and  rubber tappers are extraordinary cartographers.

Works Cited
The Future of Amazonia. Woods Hole Research Centor. 23 Sep. 2002. <http://www.whrc.org/science/tropfor/tropfor.htm>.
 
 

        Also, I found information about Avança Brasil Program, which will affect system interaction in Amazon. The Brazilian government is making large-scale investments in development projects in the Amazon region through its Avança Brasil (Forward Brazil) Program. Among the government's goals for the next few years are the
 expansion of the paved road network into central Amazonia, and the construction of ports, waterways, railways and hydroelectric power plants.The Avança Brasil is predicted to the deforestation of 120,000 to 270,000 km2 of primary forest over the next 25 to 35 years. This program could trigger three vicious feed back mechanisms of environmental impoverishment in the region.
         1. In the first vicious feedback, the increased land supply along the highways will stimulate ranching and subsistence agriculture, contributing to an increase in accidental fires since these land uses depend upon fire as a management tool.
         2.In the second feedback, selective logging and drought events increase the flammability of large areas of forest, and many forests catch fire.
         3.In the third vicious feedback, expanded deforestation enhanced by the two previous feedbacks would inhibit rainfall, causing an increase in the occurrence of accidental fires. These, in turn, would reinforce phenomena
 that further inhibit rainfall. Rain is inhibited both by smoke and by the reduction in evaporation that results from deforestation and burning.
         Finally, the plans to build and pave roads in Amazonia could affect as much as one fourth of the indigenous lands, national parks and priority areas for biodiversity conservation. The immigration of colonists, ranchers and loggers stimulated by the proposed all-weather roads poses a risk to these lands. These areas have remained intact so far because they were "passively"protected by their inaccessibility.

Works Cited
The Future of Amazonia.1 Jun. 2000. Woods Hole Research Centor. 23 Sep. 2002. <http://www.whrc.org/science/tropfor/research/setroadsen.htm>.

Overview of my thinking.

We are looking for some specific places, such as the place that is deforested, to model system interaction

1.I have to search for the place that has this problems.
    I found Avança Brasil Program which affected the forest by planned paving and/ or pavement recuperation of roads.

2.I have to search which areas does this program affect
    I found a map that shows this area. I found only the name of some national forests that will be affected, such as Itaituba II, but I could not find the information about these national forests on the website at that time.

3.I have to choose and indicate one area that worth spending time modeling system interaction. Also I have to choose some plants and animals that were common in this area and important for the economic of Amazon region.
    I could not find the area but I tried to find some plants that are important to people, such as Orbignya Phalerata Martius (Babassu).
 
 

        "The indigenous lands that will be directly affected are: São Marcos,Yanomami, Serra da Moça, Truaru, Sucuba, Raimundão, Canauanim,
 Tabalascada, Malacacheta, Wai-Wai, Waimiri-Atroari, Gavião,Paquiçamba, Arara, Koatinemo, Trincheira/Bacajá, Rio Jumas, Cachoeira
 Seca do Iriri, Kararaô, Parakanã, Mãe Maria, Apurinã do Ig, Tauamirim,Lago Capanã, Ariramba, Lago Jauari, Baú, Nove de Janeiro, Menkragnoti and Panará.
         Of the 81 federal conservation units, 18 (22%) will be directly affected, also four ecological stations (Caracaraí, Niquiá and Anavilhanas), three national parks (Viruá, Chapada dos Guimarães and of Amazônia), one biological reserve (Uatumã), one extractive reserve (Tapajós-Arapiuns), five national forests (Tapajós, Itaituba II, Itaituba I, Altamira and Humaitá), one ecological
 reserve (Sauim Castanheiras) and two research areas of the Forest Fragment Biological Dynamics Project.
         Among the existing 73 state conservation units in Amazonia, eight (11 %) would be directly impacted: six environmental protection areas (Caverna do Moroaga, Margem Esquerda do Rio Negro, Margem Direita do Rio Negro, Lago Cuniá, Cabeceiras do Rio Cuiabá and Chapada dos Guimarães), one state park (Rio Negro\Setor Sul) and one sustainable yield state forest (Rio Madeira). "

Works cited
Report of the Scenarios Project.1 Jun. 2000. Woods Hole Research Centor. 1 Oct. 2002. <http://www.whrc.org/science/tropfor/research/setroadsen.htm>
 
 

Michael J. Balick. "Green Treasure-The Useful Plants of the Amazon Valley." Journey Into Amazonia. 4 Feb. 2000. PBS. 1 Oct. 2002. <http://www.pbs.org/journeyintoamazonia/plants.html>

After the discussion, our group decided not to specifically focus on particular areas. We are interested to model system as general and we need some non-living system interaction. Therefore, I searched for the information about the nutrient cycles in rain forest in An Introduction to Tropical Rain Forests, second edition by Tic Whitemore.

        I summaried the nutrient cycle as following.
        "Rain washes the air and smoke containing nutrients, such as nitrogen and sulphur, which come from the forest burning. 99% of water reaches the ground by penetrating the canopy as throughfall and some rain reaches the ground by trunk flow. The concentration in throughfall is greater than in rainfall because rain leaches nutrients from the leaves. Besides, the forest floor gets the nutrients from litterfall which is divided into two components: fine and coarse litter. Fine litter is mainly leaves but also includes flowers, fruits, and fine twigs. Coarse litter, which is brances, limbs, and falling tree trunks.
        After the litter has decomposed the nutrients pass into the mineral soil and may be taken up by the roots or leached out into streams. There may also be nutrient input into the soil from the breakdown of soil minerals. These may either be part of the rock on which the soil lies or in some places may be volcanic ash which has been carried in after eruptions.
        Most of the plant roots are in the top 0.1-0.3 m of the soil. The layer of roots is important for the uptake of nutrients. Most tree species have mycorrhizas and these enhance nutrient uptake, especially phosphorus.
        All rain forests receive small amounts of nutrients in rainfall. Some nitrogent is converted to nitrates in  thunderstorms. For othe nutrients, the amounts received are highest near the sea and very low a long way inland. In central and upper Amazonia, there is an important distinction between rain forests on deep soils which receive nutrients solely in rainfall and others with soil parent material within the rooting zone which also receive them from that material. In the former, nutrient cycles are almost closed, and recycling is very important. In the latter the cycles are more open. The amounts of most nutrients lost in streamwater vary with the lithology of the catchment. Losses are lower from infertile soils especially from those of Amazonia. There is also less annual nutrient loss from forests in seasonal climates. Phosphorus and nitrogent does not follow this pattern.
        Rain forests on flat terrain or older deep soils, such as Central Amazonia (which is the most extensive very deep soil) have no input from decomposing rock like the rain forests on rugged, hilly terrain where the soil is shallow. Although there is addition of nutrients at the bottom of the soil in old deep soils, it is beyond rooting depth, outside and uncoupled from the ecosystem."

After the special discussion, our group wants to find some relationship among plants, animals, air, soil and water. I search for the relation between air and plant in Forest Ecology: A Foundation for Sustainable Management, 2nd Edition by J.P.Kimmins.
 
 

1. disseminate pollen, spores, or seeds.
2. affect the exchange of gases between plants and the atmosphere. If leaves are bent as they flap in the wind, air is pumped in and out of the leaf air spaces through the stomata, and this accelerates the exchange of CO₂ and O₂
3. increase the evaporation of water from plants and remove a layer of warm air from around the plant(wind acts to lower temperature).
4. affect the distribution of net growth between different parts of the plant, and the survival of buds and leaves stem and root growth.
5. High winds can produce mechanical damage, and sustained, directional winds can reduce the quality of stemwood for human uses by causing the formation of tension or compression wood.
6. If the wind carries mineral particles, mechanical damage can become severe.

The roughness of the vegetation provides a friction surface which significantly reduces the overall wind velocity but increases wind turbulence.

Works cited

We decided to look for some equation modeling ecology system and each person present one interesting equation to the group.
I found the model for a deterministic one-predator-one-prey system with continuous growth of Lotka and Volterra in page 41 of Model Ecosystems by Robert M. May.
 

The equation is

d H(t) / dt = H(t) [a-alpha* P(t)]

dP(t) / dt = P(t) [-b+beta*H(t)]

H(t) = the populations of prey
P(t) = the populations of predator
t=time
a=the birth rate of the prey
b=the death rate of the predator
alpha, beta=the interaction between the species (all are positive numbers)

"These equation constitute the simplest representation of the essentials of the nonlinear predator-prey interaction (41)."

I have been reading the user's manual of Vensim. Vensim is a program that can create the relationship among factors and drawing graphs from an equation representing the relation among factors. We can change the value of variable to see the effects toward other factors and compare the  original value with the new value by using graph.

 We will try to use this program to represent the relationship among different ecosystem's factors, such as plants, animals, water, soil and atmosphere. Also, we will try to find some equations that relate each factors and try to experiment with the value of variable and see what happpens, what is the effects to other factors if a value of one factor changes.

Also, I think that if we want to find a way to preserve the Amazon rain forest, we should know the definition of "ecosystem health", so that we know the scope of our work and what should we do to retain the health of ecosystem in Amazon rain forest.

On page 507, Kimmins, the author of Forest Ecology, cited Kolb et al. (1994) who use the combination of "our understanding of ecological succession, ecosystem function, the physical environment, and population and community ecology."

"Kolb et al. proposed that a healthy forest ecosystem should have the following characteristics:

• the physical environment, biotic resources, and trophic networks to support productive forests during at least some seral stage
• resistance to catastrophic change and/ or the ability to recover from catastrophic cahange at the landscape level
• a functional equilibrium between supply and demand of essential resources (water, nutrients, light, growing space) for major portions of the vegetation, and
• a diversity of seral stages and stand structures that provides habitat for many native species and all essential ecosystem processes."

Works cited

Kimmins, J.P. Forest Ecology: A Foundation for Sustainable Management. 2nd Edition. New Jersey: Prentice-Hall, Inc., 1997.

6 Nov 2002

I have been reading how to using Vensim to model a system on Roadmap, a web guiding to model a system by using Stella and Vensim. Following the guide, I built an example of model, "The Stock, Flow, and Feedback Structure" This model focusing on what affects federal debt. Some of variables are Net Federal Deficit, Total Government Expense and Government Revenues. In this model, I insert equations connecting among variables, intial value and unit to each variable and the program create graphs representing relations. I can simulate a model, vary the value of a variable and study the effect to the system by looking at a graph.

This information will hopefully help the group creating ecosystem models.

Works Cited

Repenning, Nelson. "Formulating Models of Simple System Using Vensim PLE." Road Maps: A Guide to Learning System Dynamics. <http://sysdyn.mit.edu/sdep/Roadmaps/RM2/D-4697-2.pdf>

11 Nov 2002

Our group has a specialy meeting at McCormick House. We found a carbon cycle diagram that we could use Vensim to present and stimulate the model.  The good thing for this diagram is that it has the approximate rate of interaction between variables. For example,  deforestation will affect the total amount of C in the atmosphere with rate X.  We are finding some initial values such as total amount of C in Amazon rainforest and the rate of deforestation to put in the model.

17 Nov 2002

Group 9 is broken down following Thursday's plan. I join the cycle group and we had a meeting on Sunday. In this meeting, we shared our knowledge about N cycle, water cycle and C cycle. Because of limited amount of time, we may only create only one model of C cycle by using Vensim. Also, we think that we should suggest some monitoring tecnique in the model such as using sattlelites.

For other cycles, we might draw diagrams to present their significances.

I worked with Jiwa from land group and used Vensim to create Nitrogen cycle and nutrient cycle diagram. We produced a document about Human Impact toward nitrogen cycle and nutrient cycle in Amazon rainforest.
 
 

(Adapted from figure 8.6, p. 170) Chameides, W.L., and E.M. Perdue. Biogeochemical Cycles: A Computer-Interactive Study of Earth System Science and Global Change. New York: Oxford University Press, Inc., 1997

(Adapted from fig 8.5, p.161) Whitmore, T.C. An Introduction to Tropical Rain Forests. New York: Oxford University Press, 1998.

 These diagrams have been constructed for the purpose of illustrating the relationship between different states of nitrogen in the global environment.  Human impact factors relevant to the Amazon region are illustrated in red, with blue arrows indicating their either decreasing or increasing effects on various stages of the nitrogen cycle.  The Global Biogeochemical Cycle of Nitrogen diagram illustrates this dynamic process for the globe.  The Inorganic Nutrient Cycle diagram shows the path of nitrogen and associated cations on a more detailed and rainforest-specific level.  From these figures, the data obtained through experimental procedures can be more easily visualized and explained.

Disruptions to the Amazonian nitrogen cycle can be studied on both global and local scales.  Considered globally, we can see human contributions to increased nitrous oxide levels (greenhouse gases) in the atmosphere due to slash-and-burn techniques for clearing the land.  This method is combustion of organic matter, causing a release of this biological nitrogen in the form of N20 and NOx at a estimated global rate of 40 Tg (1012) per year .

Observed on a local scale of the Amazon basin itself, increases in fertilizer use have certain consequences for the native vegetation.  The most measurable effect is that of water contamination due to fertilizer run-off.  When excess nitrogen is applied to a region in the form of fertilizers, it is not retained by the soil as added fertility.  Rather, this nitrogen (in the form of NO3-) is leached from the soil into the surrounding water system.  This leads to eutrophication of surrounding bodies of water .  In the soil itself, this process depletes the reservoir of positive ions (Ca2+, K+, etc.), which are transported with the negative nitrate ions.  The presence of this available nitrogen also disrupts the natural nitrogen fixation sequence, as microorganisms are no longer required to provide a nitrogen source for the surrounding vegetation, and thus no longer participate in fixation .  This presumably adds to the complexity for any kind of land rehabilitation, as the natural nitrogen fixation has been temporarily disabled.

Not only is the use of the land disruptive to the nitrogen cycle, but also its conversation to such uses.  When land is initially stripped of its natural vegetation, the decaying biomass infuses the soil with nitrogen compounds.  If left fallow, this nitrogen is leached away, again with associated cations, as there are no roots to absorb it .  Also, without vegetative cover, decomposer, such as worms and termites, and microorganism populations, important for nutrient cycling, are diminished .  If cultivated, the demands of the crops often exceed the holding capacity of the soil and fertilization is required, often carried out to excess, with the effects previously outlined.
 

Works cited.

 Vitousek, Peter M. et al. Human Alteration of the Global Nitrogen Cycle : Causes and Consequences. Ecological Applications (7) 1997.
 Committee on Tropical Soils, Soils of the Humid Tropics. National Science Academy 1972: 68
 Whitmore, T.C.  An Introduction to Tropical Rain Forests.  Newyork: Oxford University Press  1998: 16