Supporting Materials

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
mouse button.

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:



Screen Size

320 x 200
320 x 200
640 x 480
320 x 200
320 x 200
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.

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

The nutrient flows in an ecosystem food web.

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.

Some Background Information on the Biomes Selected for this Activity

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.

A short, easily readable article that addresses several of the themes of this module (dispersal, productivity, population, species diversity under varying environmental conditions). It's a good follow-up to the more abstract discussion in the Background Information using a common example. Goudie, Andrew. 1986 (or any later edition). The human impact on the natural environment. Oxford: Basil Blackwell. (See especially the chapters on human impact on vegetation and on soils.) A classic text in introductory geography that introduces the subject of this module. The chapter on human impacts on vegetation gives a broader overview than is provided in this module, discussing various basic ways in which vegetation can be impacted and how these affect (and even create new) ecosystems and biomes (savanna, secondary rain forest, prairie landscapes, etc.). A similar broad overview is given in the chapter on soils. Holling, C.S. 1995. Sustainability: The cross-scale dimension. In: Defining and measuring sustainability: The biophysical foundations. Mohan Munasinghe and Walter Shearer, eds., 65-75. Tokyo, New York: United Nations University and The World Bank. This is a challenging if short piece by an ecology authority who knows how to put geography to work, and who is not afraid to seek analogies between ecological and social systems! The chapter gets at the module concepts of diversity, disturbance, pattern, and connectedness among ecosystem components across various scales. Holling applies these to a discussion of defining "sustainability" and as such goes beyond the module per se. A stimulating and long-lasting piece for the advanced reader. Alternatively, an instructor could walk students through the text -- it's cutting-edge ecology/biogeography and worth the effort. Kareiva, Peter M., Joel G. Kingsolver, and Raymond B. Huey, eds. 1993. Biotic interactions and global change. Sunderland, MA: Sinauer Associates Inc. A broad-ranging anthology of the current state of the art in biotic changes in response to global climate and other changes. Contributions vary from an introductory section on how and why landscapes change to how the physiology and populations of organisms change in response to environmental change, to evolutionary and community-scale responses to environmental change, to a number of contributions on landscape change and habitat fragmentation. LaRoe, E.T. et al., eds. 1995. Our living resources: A report to the nation on the distribution, abundance and health of U.S. plants, animals, and ecosystems. Washington, DC: U.S. Department of the Interior, National Biological Service. (Gov. Printing Office, Stock # 024-010-00708-7). An excellent resource! Pick any U.S. plant, animal, ecosystem, or major human-induced impact and find crucial references to the subject in this 530 page book. Short summaries for each describe the distribution, abundance, and state of health or ill-health of the particular plant, animal, biotic community or issue you are interested in. Not an exhausting account but a great starting point for student projects, or for the instructor to read up on something quickly. (See also Root and Weckstein; Oglesby and Smith; and Morse, Kutner, and Kartesz elsewhere in this annotated bibliography.) 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. The report is an accompaniment to a wonderful, colored map of U.S. ecoregions. (A small black and white copy is included in the Supporting Materials section of this module.) The descriptions for each ecological section include summaries of geomorphology, geology, soils, vegetation, fauna, climate, disturbance regimes, current land sue, and cultural ecological aspects pertinent to the section. A good background resource, and possible basis for some of the activities. McNeely, Jeffrey A. et al. 1990. Conserving the world's biological diversity. Washington, DC: World Resources Institute. A comprehensive book explained the meaning and importance of biodiversity and the threats to it while also showing with many practical examples from around the world how it can be preserved. (Also available from Earthscan Books.) Morse, Larry E., Lynn S. Kutner, and John T. Kartesz. 1995. Potential impacts of climate change on North American flora. In: Our living resources: A report to the nation on the distribution, abundance and health of U.S. plants, animals, and ecosystems. LaRoe, E.T. et al., eds., 392-395. Washington, DC: U.S. Department of the Interior, National Biological Service. A short research article that examines the vulnerability of different plant species to climate change. What is it that does or doesn't allow a species to adapt to altered climatic conditions? The article discusses species rarity, vulnerability, dispersal, persistence, ability to migrate, disturbance, and landscape fragmentation in order to understand potential impacts on the abundance of species. A very good reading to accompany this module! Oglesby, Ray T. and Charles R. Smith. 1995. Climate change in the Northeast. In: Our living resources: A report to the nation on the distribution, abundance and health of U.S. plants, animals, and ecosystems. LaRoe, E.T. et al., eds., 390-391. Washington, DC: U.S. Department of the Interior, National Biological Service. A short research article that reports on investigations of date changes of first bloom of flowering plants and of first arrival of migratory birds over a 70-90 year period which indicate that there is a steady trend to earlier bloom and earlier arrival. The authors explain this by a warmer climate and discuss alternative explanations. Peters, Robert L. and Thomas E. Lovejoy, eds. 1992. Global warming and biological diversity. New Haven, CT: Yale University Press. Compared to the Kareiva et al. anthology, this edited volume is more narrow in focus: of the global changes, it is mainly concerned with global warming, and of the biotic aspects, it concentrates on biological diversity. Yet, the geographic and methodological coverage is exemplary. The chapters in the book discuss biodiversity in various types of habitat and climatic zones, and they present several methods to study biological changes ranging from the analysis of geological records to computer modeling of biological responses to global warming. Of particular relevance to this module are chapters on changes in range, competition, and composition of ecosystems, on population dynamics, and on responses of soils and biotic processes in soils to climate change. Reid, Walter V. and Kenton R. Miller. 1989. Keeping options alive: The scientific basis for conserving biodiversity. Washington, DC: World Resources Institute. A short book that discusses the value of biodiversity, the degree of endangerment, and the choices over what should be conserved, and how, using the best available scientific information at the time. Still a valuable resource. Root, Terry L. and Jason D. Weckstein. 1995. Changes in winter ranges of selected birds, 1901-1989. In: Our living resources: A report to the nation on the distribution, abundance and health of U.S. plants, animals, and ecosystems. LaRoe, E.T. et al., eds., 386-389. Washington, DC: U.S. Department of the Interior, National Biological Service. One of the short overview research articles included in this compendium that investigates range changes of birds over 90 years in relation to climate change in the United States. An interesting example of research methodology as much as of the results that indicate significant changes. Rosenzweig, Cynthia and Daniel Hillel.1993. Agriculture in a greenhouse world. National Geographic Research & Exploration 9, 2: 208-221. A scientific, yet very readable article about the likely environmental changes as a result of global warming that will affect agriculture. The authors discuss physiological effects of CO2 enrichment, thermal changes, hydrological changes, changes in climatic variability, soil fertility and erosion, pests and diseases, and interactions between agricultural and natural ecosystems that will differentially alter agricultural productivity across the globe. Stevens, William. 1992. Global warming threatens to undo decades of conservation efforts. The New York Times, February 25, 1992. An article that reports on the impacts of global climate change on ecological systems in general, and on Peter and Lovejoy's book mentioned elsewhere in this bibliography in particular. In short, a quick and good, readable account of some potential impacts of climate change on biological systems with a distinct geographic slant since it juxtaposes human-set boundaries around nature reserves with the ever-changing range shifts of species. Turner, B.L. II, R.H. Moss, and D.L. Skole, eds. 1993. Relating land use and global land-cover change: A proposal for an IGBP-HDP Core Project. IGBP Report No. 24/HDP Report No. 5. Stockholm: IGBP. A scientific text that focuses primarily on land use and land-cover change yet is relevant to this module in that it looks at relatively unaltered natural ecosystems and human-altered environments, and relates changes occurring on a global scale to the human dimensions of global change (driving forces, impacts, responses). Valiela, Ivan et al. 1996. Hurricane Bob on Cape Cod. American Scientist 84, 2: 154-165. Vitousek, Peter M. et al. 1996. Biological invasions as global environmental change. American Scientist 84, 5: 468-478. This article by one of the authorities (and coauthors) on global biological changes does not only touch upon one of the principal themes of this module -- invasion, it also views the interaction between the biosphere and global change from a slightly different angle: rather than looking at the impacts of global change on the biosphere, Vitousek et al. show that biological changes like species invasions constitute a type of global change. Wilson, Edward O. 1990. Threats to biodiversity. In: Managing planet Earth: Readings from Scientific American, 49-60. New York; W.H. Freeman & Co. Wilson focuses on habitat fragmentation, mainly through deforestation in the tropics, and its impacts on species diversity. A good read on destructive human interference in natural processes. World Resources Institute. 1992. Global biodiversity strategy: Guidelines for actions to save, study, and use earth's biotic wealth sustainably and equitably. Washington, DC: World Resources Institute. A great resource for the practically oriented. A book of policy-oriented steps for public and private sector decision-makers to preserve biotic resources and how to pay attention to the social and economic contexts in which such decisions have to be made. Also includes background information, a glossary, list of acronyms common in this field, and an accounting of biodiversity loss as of the date of publication.