Technical Note on Computer Display of Visuals
Note: To download files on to your disk or hard drive hold down
the shift key and click on the hotlinked file with your left
The animated slide shows are designed to run on the animator player program ANIPLAY.EXE (To download the animator player program on to your disk or hard drive hold down the shift key and click on the hotlinked file with your left mouse button). It is a DOS based program, although some Windows-based programs recognize the two formats generated by Autodesk Animator programs. Other shareware programs are available to view these graphics. ANIPLAY can be run in multiple screen modes. The materials used here operate in two screen modes. These area as follows:
320 x 200
Screen size can be changed under the file menu.
The disk with the ANIPLAY.EXE file also contains a number of video drivers in a \RESOURCES subdirectory. This subdirectory and its files should be copied onto a \RESOURCES subdirectory within the directory to which you copy the ANIPLAY.EXE file and the individual slide show files.
Caution: ANIPLAY.EXE may have difficulty with some computers which use 386 extended memory managers. If you encounter this problem, edit your CONFIG.SYS file, putting the word rem at the beginning of the line which refers to the 386 manager. This remark notation should be removed following use.
The menu blocks can be removed form the screen by clicking the right mouse button with the cursor outside of the menu box. Frames can be advanced with the right cursor button. The menu blocks can be restored on the screen by clicking the right mouse button. The movie can be played continuously by clicking the pointer on the >> symbols in the menu box.
Print-Outs of Food Web Slide Show
The following pages contain print-outs of each frame from the food web slide-show. They may be photocopied or reproduced as overhead projections.
Supporting Materials for the Activities
The following pages contain all those Supporting Materials referred to in the Activities. They are numbered according to the activities in which they are used. For example, Supporting Material 1.5 would accompany Activity 1.5. Use these materials as overheads or handouts for students, especially when other resources are not available at your institution.
Note that the first item, Supporting Material 1, is somewhat of an exception to the notational scheme. It is a general handout that accompanies the module as a whole rather than just a particular activity. We recommend introducing it to the class early on since it is meant to help students acquire the essential skill of note taking from readings.
|Supporting Material 1|
Taking notes that make sense -- even a year from now ...
As you work through the reading assignments for this and the following exercises, do not just read the articles, or just underline important passages. For understanding and remembering the arguments it is even more important to take notes on what you read. Taking concise yet comprehensive notes is a big step in preparing for classes and exams and to recall something you read or heard about.
If you are experienced in taking good notes, proceed to do so as you read your assigned materials. If you feel you could use some guidance in how to improve on this skill, follow the steps outlined below.
The Nature and Consequences of Indirect Linkages Between Climate Change and Biological Diversity
3 Read the text (again)!
If you have not read the article yet, do so now. Stop once in a while and recall what you
thought the text would be about. Are your expectations met? (If they are not, you will
probably be quite frustrated and most likely bored!)
4 Note the main argument!
Having had an expectation of the text and an actual read or two through it, what would
you say is the main argument of the text? In other words: how would you describe to a
friend what the gist of the article is?
5 Concisely list the supporting arguments under
each heading (or subtitle)!
Every argument needs supporting arguments, data, and other evidence to be convincing.
As you go once more through the text -- paragraph by paragraph -- list in keyword style
or short sentences what the author(s) have to offer for supporting evidence and arguments.
If you can't decide what is important and what is not (and thus should be omitted from this
listing), ask yourself whether you found it important to know or mention this particular item
to understand the logic behind the argument. If not, leave it out! You are most likely to
forget everything that is not essential to the argument anyway.
6 Check whether it makes sense!
Once you're through with Steps 1-5, look over your notes once again and see whether
they make sense. (The best test is really three days after taking the notes, i.e. when you're
already somewhat removed from having read the article. If they still makes good sense,
you took good notes!) If you feel as if you lost the thread of the argument somewhere, then fill in the blanks. Also compare the length of your notes with the length of the article: if your notes are as long as the original article, you simply paraphrased the text. By definition notes are short and never as prosaic as an essay!
|Supporting Material 1.5|
Map of Ecoregions of the United States of America
A black and white reproduction of a map of ecoregions is supplied on the next page. The colorful original is available with an accompanying report from the U.S. Department of Agriculture.
McNab, W. Henry and Peter E. Avers, comps. 1994. Ecological subregions of the United States: Section descriptions. Administrative publication WO-WSA-5. Washington, DC: U.S. Department of Agriculture, Forest Service.
USDA Map: Ecological Subregions of the United States
|Supporting Material 2|
An ecosystem is composed of plants and animals living together in an environment that has abiotic resources of soil (partly biotic), water, and air. In the schematic diagram above, only a few of these components and their interactions are illustrated. Small biotic elements are not included here. These include insects and microorganisms (decomposers) that play a major role in the breakdown of litter (organic material on the soil surface that is not fully decomposed and reintegrated into the organic component of the soil). Ecosystem productivity (the amount of biomass/organic material produced) depends on the ability of the vegetation (primary producers) to use solar energy to capture atmospheric carbon (in a process called photosynthesis) in exchange for oxygen and water vapor (respiration), and its ability to withdraw water and nutrients (nitrogen, phosphate, potassium, calcium, and other elements) from the soil (uptake). The next level of biotic elements in the food web (herbivores) capture part of the nutrients produced by the vegetation. Some nutrients are not consumed and most of what is consumed is lost to respiration and fallout (hair, feathers, skin, feces, urine). Carnivores (meat eaters) consume the herbivores, again converting only a portion of the available herbivore biomass to carnivore biomass. Complete consumption of a lower level would result in extinction of that level and consequently of all levels above. Dead animals and plants become litter, which is the food source for scavengers. The remaining plant and animal litter supports insects, bacteria, and other micro-organisms that convert the nutrients left in the litter back into a form that primary producers can take up, thus closing the nutrient cycle.
Simplified Ecosystem Nutrient Cycle Model. In the example below only the primary production trophic level is shown. Harvest by humans or other animals occurs if the material is removed from the site; otherwise the consumed portion of vegetation is returned to the system as fallout. The circles represent ecosystem nutrient reservoirs (storage compartments). Two independent inputs are involved: (1) the nutrients provided through soil development from the soil parent material (weathered rock) and (2) nutrients contributed from the atmosphere to the surface with precipitation or as dry atmospheric deposition (dustfall). Nitrogen, for example, can volatilize and then flow to and from the atmosphere. To simplify the model, we can consider respiration as a positive net input. The ecosystem would collapse if the balance was sustained as negative. All other transfers in the model are set as annual rates (percent) multiplied by the storage in the contributing nutrient reservoir. Harvest, erosion, and leaching represent losses to the local ecosystem. In many managed ecosystems, there is additional human input of nutrients through fertilization.
The model above can be expressed as a series of equations for each annual time step and for each nutrient storage compartment in the simulation model we use in this activity.
L1 = (L0 + (B0 * f) + n + r) - ((L0 * d) + L0 * e).
S1 = (S0 + (L0 * d) + w) - ((S0 * u) +S0* l).
B1 = (B0) (S0 * u) - ((B0 * f) + B0 * h).
Where: d = decay, e = erosion, f = fallout, h = harvest, l = leaching, n = nutrients applied, r = respiration, u = uptake, w = weathering, and for time period 1, L1 = litter, S1= soil, B1= biomass. Loss rates from a compartment cannot total more than 100%. If all nutrient storage compartments started (at time 0) with 33 units and the transfer rates were as follows; d = 0.9, e = 0.05, f = 0.05, h = 0.0, l = 0.2, n = 0, r = 9, u = 0.7, and w = 0.01, then at time 1 we would get:
L1 = (33 + (33* 0.05) + 0 + 9) - ((33 * 0.9) + 33 * 0.05) == 43.65 -31.35 = 12.3
S1 = (33 + ((33 * 0.9) + 0.01) - ((33 * 0.7) + 33 * 0.02) = 35.71 - 29.7 = 6.01
B1 = (33 + (33 * 0.7) - ((33 * 0.1) + 33 * 0.0) = 56.1 - 3.3 = 52.8
In this example, the high transfer rates result in a rapid adjustment, i.e., it would take only a brief period before the nutrient storage in the different compartments would stabilize.
Simulation. In the highly generalized mathematical model we use here, the high transfer rates between compartments are partly controlled by temperature and water availability. Human-induced climate changes alter the rates of these nutrient transfers by altering the water balance and by changing the temperature regime in ways that favor some plants and decomposing organisms over others. If temperatures exceed the optimum range for all plants and decay organisms present, production will decrease. Modeling these effects would require adjusting the uptake, fallout, and decay rates in the model to reflect possible ecosystem responses to climate change. By modeling the effects of a single element change, such as fallout rates, we can test how such changes cascade through the system. Only in the world of simulation modeling can we treat one variable at a time. Otherwise, as in the conversion of tropical rainforest (selva) to rangeland, flow rates and storage levels change concurrently. Such a land cover change radically alters the biomass fallout rate while also changing the range of plant species which translates to a change in the rate of nutrient uptake from the soil.
|Selva biomes exist in areas where temperatures and rainfall are sufficiently high that evergreen plants do not experience low temperatures or water stress. The vegetation is dominated by broadleaf evergreen forest, found extensively within 20 degrees of the equator. The selva has by far the highest net primary productivity of any terrestrial ecosystem (~ 2000 grams/meter2/year). The mix of species is extremely high. That complexity was once thought to indicate very long evolution of the plant assemblage; however, analysis of fossil pollen indicates that the assemblages we see today have existed for only a few hundred to a few thousand years. Most of the plants are shallow rooted because of the reliability of precipitation and the fact that nutrients are captured before they go very deep. In fact, some trees have root systems that envelop their own trunk, presumably to capture the nutrients in water flowing down the stem. This adaptive strategy denies these nutrients to other plants. The soil resources of tropical rainforests are highly varied, but high acidity, low fertility, and low accumulation of surface litter are common traits of soils under selva.|
|The tundra biome represents the cold extreme among terrestrial biomes. These are cold deserts, but low plant demands for water (because temperatures hold down transpiration rates during a very short growing season) and the frozen substrate keeps soils moist. The freezing temperatures for much of the year and the often saturated surface keep decomposition rates low, but biomass production is similarly low. Except for extremely low latitude deserts, the tundra has the lowest net primary productivity of any terrestrial ecosystem, (~ 150 grams/meter2/year). The species mix is very low and is dominated by sedges, grasses, dwarf willows, mosses, and lichens.|
|The steppe or grassland biome's net primary productivity has a very wide range (~ 700 +/- 500 grams/meter2/year). Before vast human alteration for agriculture, the steppe was the most abundant biome on earth. Most of the world's great grain producing regions were carved from grasslands. The soils are well drained; they have high nutrient holding capacity because of the quality of the clay minerals present and the high amount of organic matter in the surface horizon. Prior to cultivation, the nutrient status of grassland soils was very high.|
|Support Material 4|
|Annotated Bibliography of Additional and Supplementary Readings|
The following readings are suggested as introductory papers to biogeography, to the connection of biogeography and the human dimensions of global environmental change, or as case studies to accompany Activity 3 and others. Depending on the larger scope and purpose of your course in which this module is being used, these articles may also lead to related topics or deepen students' and instructors' understanding of issues discussed here (e.g., land use and land cover change, the significance of biodiversity loss to society).
Bergelson, Joy. 1996. Competition between two weeds: Groundsel and Bluegrass compete based on germination, litter and open parcels. American Scientist 84, 6: 579-584.