What defines a system?

In this course, we will refer to the term "system" repeatedly, so it is worthwhile to think about how systems are defined. A basic definition of a system is "a set of components and their relationships". Rather than dwelling on this definition in the abstract, it's probably best to immediately think of how the definition applies to real examples from this course. An ecosystem is a type of system you may have heard of, in which the components are living things like plants, animals, and microbes plus a habitat formed of natural, urban, and agricultural environments, and all the relationships among these component parts, with an emphasis on the interactions between the living parts of the system and their interactions, for example, food webs in which plants feed herbivores and herbivores feed carnivores. A food system, as we have just begun to see so far, consists of food production components like farms, farm fields, and orchards, along with livestock; food distribution chains including shipping companies and supermarkets, and consumers like you and your classmates, with myriad other components like regulatory agencies, weather and climate, and soils. In the case of food systems we have already pointed out how these can be considered as human-natural (alternatively, human-environment) systems, where it can help to see the system as composed of interacting human components (societies, companies, households, farm families) and natural components like water, soils, crop varieties, livestock, and agricultural ecosystems.

Fig. 1.2.1. A simplified diagram of a typical ecosystem. Ecosystems are a common system type analyzed by geoscientists, ecologists, and agroecologists. The black rectangular outline is one way to define a boundary for the ecosystem, where climate and sunlight fall outside the system but provide resources and define the conditions under which the ecosystem develops. This diagram can also be considered a type of concept map where for example 'sun', 'plants', and 'climate' are components, and the arrows connecting the components are relationships in the system. These relationships are now labeled as either flows (of energy, food, nutrients) or causal links, like the way that dead plants and animals end up feeding soil microbes, or the ecosystem affects the climate over time. You may be able to see how this simplified diagram could represent a far more complex system containing hundreds of plant and animal species and thousands of types of microbes, interacting in complex ways with each other and the environment. Keep this diagram in mind as a possible example when you think about completing your preliminary concept map of a regional food system at the end of unit 1.

Click for a text description of the ecosystem image.

A diagram of a typical ecosystem. Soil resources is on the bottom. The sun is at the top. There is a black line (ecosystem boundary) drawn around four boxes and the soil. The four boxes are carnivores (including humans), herbivores (including humans), plants, and microbes. Lines from carnivores, herbivores, and plants go to microbes and say "feed". There are "feed" lines from plants to herbivores and herbivores to carnivores. A line from the sun to inside the ecosystem boundary says, "sunlight energy for plants". A line from soil resources to microbes says, "supply nutrients, water, habitat. A line from microbes to soil resources says, "replenish and cycle nutrients". A line from soil resources to plants says, "supply nutrients and water stored in soils". Lines from plants to microbes and plants to soil resources say, "replenish organic matter". Outside the ecosystem boundary is "climatic conditions". A line from climatic conditions to the ecosystem says, "provides basic conditions, rainwater". A line from the ecosystem to climatic conditions says, "impacts on climate change".

Credit: Steven Vanek

Behavior of Complex Systems

Systems that contain a large number of components interacting in multiple ways (like an ecosystem, above, or the human-natural food systems elsewhere in this text) are often said to be complex. The word "complex" may have an obvious and general meaning from daily use (you may be thinking "of course it is complex! there are lots of components and relationships!") but geoscientists, ecologists, and social scientists mean something specific here: they are referring to ways that different complex systems, from ocean food webs to the global climate system, to the ecosystem of a dairy farm, display common types of behavior related to their complexity. Here are some of these types of behaviors:

• Positive and negative feedback: the change in a property of the system results in an amplification (positive feedback) or dampening (negative feedback) of that change. A recently considered example of positive feedback would be that as the arctic ocean loses sea ice with global warming, the ocean begins to absorb more sunlight due to its darker color, which accelerates the rate of sea ice melting.
• Many strongly interdependent variables: this property results in multiple causes leading to observed outputs, with unobserved properties of the system sometimes having larger impacts than we might expect.
• Resilience: Resilience will be discussed later in the course, but you can think of it here as a sort of self-regulation of complex systems in which they often tend to resist changes in a self-organized way, like the way your body attempts to always maintain a temperature of 37 C. Sometimes complex systems maintain themselves until they are pushed beyond a breaking point, after which they may change rapidly to another type of behavior.
• Unexpected and "emergent" behavior: one consequence of the above three properties is that complex systems can display unexpected outcomes, driven by positive feedbacks and unexpected relationships or unobserved variables. Sometimes this is referred to as "emergent" behavior when we sense that it would have been impossible to predict the behavior of the system even if we knew the "rules" that govern each component part.

To these more formal definitions of complex systems, we should add one more feature that we will reinforce throughout the course in describing food systems that combine human and natural systems, which is that drivers and impacts often cross the boundary between human or social systems and environmental or natural systems (recall Fig. 1.1.2). Our policies, traditions, and culture have impacts on earth's natural systems, and the earth's natural systems affect the types of human systems that develop, while changes in natural systems can cause changes in policies, traditions, and culture.

For more information on complex systems properties with further examples, see Developing Student Understanding of Complex Systems in Geosciences, from the On the Cutting Edge program.

On the next page, we'll see an interesting example of complex system behavior related to the food system in India.

The Indian Vulture Crisis: An Example of Complex Systems Behavior

The "Indian Vulture Crisis" may or not be a familiar term to you, but it is important enough to the history of modern India that it has involved dozens of research experts as well as major changes in wildlife, human health, and government policies, and now has its own Wikipedia page (Indian vulture crisis) that you can browse. It is also an interesting example of complex systems behavior that involves food systems and unintended consequences of veterinary care for animals. The main causal links are outlined below in figure 1.2.2, and the narrative of the crisis goes as follows:

Beef cattle are hugely important to Indian food systems even though they are usually not consumed by adherents of the majority Hindu religion (however, Indian Christians and Muslims, for example, do consume beef). Cattle are also widely used as dairy animals (think: yogurt and clarified butter as important parts of Indian cuisine) and are even more important as traction animals (oxen) to till soil for all-important food crops by small-scale farmers across India. Because of their importance and to treat inflammation and fevers in cattle, in the 1990s the drug diclofenac was put into widespread use across India. However, timed with the release of this medication, a precipitous drop in the population of Indian vultures began, which became the fastest collapse of a bird population ever recorded. Vultures are not valued in many parts of the world, but scavenging by vultures was the main way that dead animal carcasses were cleared from Indian communities, especially in the case of beef cattle where the meat is not consumed. It was not until the 2000s that the cause of vulture population collapse was discovered to be the diclofenac medicine administered to cattle, which is extremely toxic to vultures eating dead carcasses. However, the consequences of this population collapse did not end with the solving of the mystery of the vulture population collapse, which was already a tragic and unforeseen consequence. Rather, the fact that vultures are a key part of a complex system resulted in further unforeseen consequences in both human and natural parts of the Indian food system. A few of these are shown in figure 1.2.2 below: first, since vultures are in fact an ideal scavenger that creates a "dead end" for human pathogens in rotting carcasses, and since they were no longer present, water supplies suffered greater contamination from carcasses that took months instead of weeks to rot, leading to greater human illness. Second, populations of rats and dogs, which are less effective carcass scavengers, expanded in response to these carcasses and the lack of competition from vultures, which resulted in dramatic increases in rabies (and other diseases) due to larger dog and rat populations and human contact with wild dogs. This is significant since more than half of the world's human rabies deaths occur in India. Finally, the vulture crisis even had implications for religious rituals in India: people of the Parsi faith, who practice an open-air "sky burial" of their dead where the body is consumed by vultures, were forced to abandon the practice because of hygiene concerns when human bodies took months instead of weeks to decompose. A final consequence of these problems was that the drug diclofenac was banned from use in India, Nepal, and Pakistan in hopes of helping vulture populations to revive. This final turn of events is an example of the human system responding to the unforeseen consequences. Additionally, alternatives to these drugs have been developed for veterinary use that have no toxicity to vultures.

Figure 1.2.2. Diagram of the causal chain leading to the Indian Vulture Crisis. This crisis contains several examples of complex system behavior and unforeseen consequences.

Click for a text description of the causal chain image.

A diagram using boxes to show the causal chain leading to the Indian Vulture Crisis. Box 1: Cattle as essential milk and traction animals in the food system. An arrow goes from box 1 to box 2: Veterinary use of diclofenac (diclofenac highly toxic to vultures). An arrow goes from Box 2 to Box 3: Collapse of vulture populations. From box 3 there are two arrows. One leads to a comment box that says, "Banning of diclofenac and alternative developed in India, Nepal, and Pakistan." The second arrow from box 3 leads to box 4: Crisis of unconsumed carcasses. A comment box that says, "vultures as honored, efficient, and most sanitary practical method of carcass disposal", also has an arrow to box 4. From box 4 there are three arrows pointing towards comment boxes as follows: dogs and rat populations expand; lack of vultures for ritual consumption of bodies in Parsi faith; contamination of drinking water in rural areas. There is also an arrow from, dogs and rat populations expand, to a comment box that says, greater incidence of rabies.

Credit: Steven Vanek

Note the properties of complex systems and human-natural systems exhibited by this example. Farmers sought mainly to protect their cattle from inflammation and speed healing in service of the food system, while pharmaceutical companies sought to profit from a widespread market for an effective medication. The additional, cascading effects of the human invention diclofenac, however, were dramatic, far-ranging, and in some cases unexpected, because of the many interacting parts in the food systems and ecosystems of Indian rural areas: cattle, groundwater, wild dogs, and human pathogens like rabies. The crisis eventually provoked responses from the human system, with impacts on human burial practices among the Parsi, laws banning diclofenac, and development of alternative medications. The search for sustainability in food systems, like those you will think about for your capstone regions, involves designing and choosing adequate human responses to complex system behavior.

Complex Systems and Interdisciplinarity

One final note on this example is to point out that to fully understand the Indian vulture crisis a large number of different disciplines were brought to bear: we need cultural knowledge about the beliefs and practical usefulness of both cattle and vultures in India. We also need biological knowledge about drug toxicity to wildlife, pathogens, groundwater contamination by microbes, and rat and dog populations. We also need policy expertise to think about transitioning food systems to less toxic alternatives to current practices. And all of these disciplines needed to be brought together in an integrated whole to assemble the diagram shown in figure 1.2.2. The purpose of this text and this course on food systems is to help you to develop some of the skills needed for this sort of interdisciplinary analysis of human-environment or human-natural systems.

Food System Examples from Household Gardens to Communities and Global Food Systems

Some of you in this course, perhaps even many of you, have had the experience of growing herbs or vegetables (Fig. 1.2.3) or keeping chickens for eggs or animals for meat. Although dwarfed by the enormous dimensions of the global food system, home food production is still a significant part of the food consumed by billions of earth's inhabitants. In other cases, small-scale fishing and hunting provide highly nutrient-dense foods, and coexist with modernized and industrial food systems, as any fishers and hunters in the class may be able to attest. These experiences of food production for personal or family consumption show natural-human interactions in a very simple way. To grow vegetables or hunt or raise animals means bringing together natural factors (seed, animal breeds, soil, water, fishing and hunting ranges, etc.) and also human factors (e.g. knowledge of plants, livestock, or wild animals, government policies) to gain access to food, as well as food storage and preparation, markets for tools and seeds, or human-built infrastructures like a garden fence or a chicken coop. This same interaction between natural and human factors is evident at a larger scale in the photo in Figure 1.2.4, which shows a landscape that has been transformed by a human community for food production.

Figure 1.2.3. This diverse home garden includes lettuce, kale, beans, sweet corn, peppers, squash, carrots, and garlic, among other crops. During the growing season, it offsets food expenses in an urban setting and offers extremely fresh food as well as an excellent way to recycle kitchen wastes as compost.

Credit: Steven Vanek

Fig. 1.2.4. Landscape near Acobamba, Huancavelica, Peru. This Peruvian landscape has been almost completely transformed for food (and firewood) production.

Credit: Steven Vanek

Beyond these experiences of auto-sufficient food production and consumption, however, most of humanity also currently depends on global and local versions of the food system which features a web of suppliers, producers, transporters, and marketers that supply all of us as food consumers. Compared to gardening, catching trout, or keeping chickens, these food systems together form a far more complex version of the interactions between natural and human factors that produce and transport the food that we then consume as part of global and local food systems.

One way of viewing these regional and global food systems is that they can be divided by the type of activity in relation to food, and dividing them into components of food production, food transport, and food consumption (Fig. 1.2.5). Like other diagrams we've seen so far, this diagram can be considered a concept map showing relationships between the different components of a food system. The main arrows show the flow of food through the system from the managed natural environments used to produce food and the end result of nutrition and health outcomes. There are some unseen or implicit relationships here as well, like the way that farming practices, technology, communication and education, and other attributes of human societies support the functioning of a food system, and are included in the outer system boundary.

Figure 1.2.5. A simplified diagram of food system components, depicting a linear progression of production, transportation, and consumption of food. It’s helpful to think of this more linear version in conjunction with the interacting natural and human and systems in figure 1.2.6 to remember that food systems are not just linear conveyor belts delivering outcomes.

Click for a text description of the food system component image.

Simplified diagram of food system components. The diagram is within a circle. At the top, is the heading, Natural Resources, and Environments. From here is an arrow pointing directly below to an oval with the word, Production. From Production, there is an arrow pointing directly below to another oval with the word, Transport. From Transport, there is an arrow pointing directly below to a final oval with the word, Consumption. From the consumption oval, an arrow leads direction below it to Nutrition and Health Outcomes. On the left side of the circle are the following items listed from top to bottom: Farming Practices and Agroecology; Food Processing; Policy support; and Food Preparation. On the right side of the circle are the following items listed from top to bottom: Technology and Infrastructure; Crop and Livestock Breeding and Biodiversity and Communication and Education.

Credit: Figure adapted from Combs et al., 1996.

In addition to this more linear or "conveyer belt" portrayal of food systems delivering nutrition from natural resources, we may also be interested in thinking about the dramatic impacts humans have made on earth systems during the Anthropocene, discussed in module 1.1. In that light, we know that these natural systems may either be sustained or degraded by management, an important response that either maintains or undermines the entire food system. For this purpose, we may be interested in a food system diagram that makes the interactions among human and natural systems very explicit. Below in figure 1.2.6 is a version of a Coupled Human-Natural Systems diagram -- again, a concept map of sorts -- developed by an interdisciplinary group of social and environmental scientists (Liu et al. 2007) to represent the human-environment interactions in food systems.

Figure 1.2.6. A food system as a Coupled Human-Natural System, a way of considering food systems that will be explored throughout the course. This more detailed presentation compared to that in module 1.1 shows that both human systems (communities, regions, food supply chains) and natural systems (agroecosystems, landscapes, water bodies) have internal interactions. Human systems also organize and modify natural systems to produce food, and natural systems respond via feedbacks (food provision, aggradation or degradation depending on the human modification and management of the natural systems.

Click for a text description of the Human Natural Coupling image.

A coupled human-natural system. Heading at the top says, Human to natural coupling: Human systems reorganize natural systems to produce food: e.g. gardens, farms, fisheries, managed forests. Below this heading are two boxes, side by side. On the left is a box with the heading, Human System. Outside of the box is a descriptor that says, human system internal interactions. There are two lists inside the box on the left. The first list is Farms, farming households; food policies; food distribution companies, consumers. The second list is management knowledge for farming, herding, hunting, fishing, etc.; local and national governments; agriculture input companies. Inside this box are arrows indicating a continuous relationship among the listed items. On the right side is a box with the heading, Natural System. Outside the box is a descriptor that says, natural system internal interactions. There are two lists inside the box. The first list is plants and animals (crops, livestock, pests, wild species); soils. The second list is the climate system and water. Below the two boxes is the heading Natural to Human Coupling: Altered ecosystems respond with food production, degradation, sustained production. There are arrows around the entire diagram indicating the continuous relationship among all items.

Credit: Steven Vanek and Karl Zimmerer; modified from the National Science Foundation.

This diagram highlights internal interactions within both the natural and human components of the food system. The natural components of food systems shown here are those we will tackle first in the first part of the course, while the latter half of the course will address the human system aspects of food systems and human-environment interactions shown as the large arrows connecting these two major components. As we saw in comparing home garden production, smallholder production landscapes and global food production chains above, food systems and their components are highly varied. However many similarities apply across the different components, actors, and environments of the food system:

• Food systems modify the natural environment and capture the productivity of the earth’s natural systems to supply food to human populations. Globally they create huge changes in the earth’s surface and its natural populations and processes.
• As portrayed in Figure 1.2.6, despite their complexity, food systems often involve coupling between human management and the response of natural systems. As pointed out by author Colin Sage in Module 1.1, the response of natural systems to human management can create sustainability challenges in food systems.
• Food systems involve the production, transportation, distribution, and consumption of food (Figure 1.2.5). The scale of these three processes can differ among food systems, which can be local, regional, and global.
• Food systems are examples of complex systems: they involve many interacting human and natural components, as well as important variability, for example, droughts, soil erosion, population changes, and migration, and changing policies. All of these affect the natural and human systems and can disrupt simple cause and effect relationships, in spite of the large-scale drivers and feedbacks shown in figure 1.2.6.

Knowledge Check

Summative Assessment: Concept Mapping and Assessment of Food Systems

First, download the worksheet to understand and complete the assessment. This assignment will require you to draw on your reading of this online text from module one, as well as several options for case studies where we have provided brief descriptions and audiovisual resources (radio clips, videos, photos) that describe these systems. You will accomplish two parts of an assignment that will not only evaluate the learning objectives for module one but will also give you practice in skills you will need to complete your capstone project. These two parts are:

1. Draw a concept map of the system that distinguishes between human and natural components or sections of the system (an example is given below)
2. Fill in a table that identifies some key components, relationships, and sustainability concerns for this system.

You will complete this assignment for your choice of two food system examples, as described in the detailed instructions below. You will first read, then draw a concept map, and then fill in a table with short responses.

Instructions

1. Choose ONE national to global food system example and ONE local to regional food system example from the options that follow this assignment page in the text (see links in outline view at right, or the link to the next page at the bottom of this page). National to global food system examples are Pennsylvania Dairy, Colorado Beef Production, and Peruvian Asparagus, while local to regional examples are the Peruvian smallholder production and New York City greenmarkets examples. Read the descriptions of the system, which may include photos, videos, audio clips, or visiting other websites. Completely read through the description of the two systems you have chosen (one national/global and one local/regional), including these external links before continuing on to the following steps (though you may certainly return to the descriptions as needed). You are welcome to consult other resources online regarding the system you have chosen since that is a skill that will be helpful when embarking on data gathering for your capstone project.
2. Using a sheet of paper, or composing in PowerPoint, develop a concept map of only ONE of the systems you chose, subject to the following guidelines:
   1. Title your concept map with the name of the system you are describing (among the five described on the following pages) and put your name on the diagram.
   2. Before you begin your concept map, draw a vertical line in your diagram to distinguish between Human and Natural components of the system to right and left, drawing on Fig. 1.2.6, 1.2.7 below, and 1.1.3 (the last one is the concept map example from the guided introductory reading by Colin Sage). However, you do not need to make your diagram look like the highly schematic diagrams in the text of the previous pages (see rather Fig. 1.2.7 below) -- you should include components that are discussed in the examples on the following pages, and connect them in the way that makes sense to you.
   3. Your concept map should be legible, but it does not need to be extremely neat since it reflects a first attempt to characterize a system. Additional components and relationships will occur to you as you draw, and you may need to squeeze them in. Therefore, leave space as you begin your diagram. If you feel your map becoming too hard to understand, please do compose a second "clean" copy.
   4. Remember that systems are defined as components and the relationships between them. If you are having trouble thinking of what to draw, think what the components are in the system (these can be boxes or ovals), and then how they are related (these may be labeled arrows)
   5. Below in Fig. 1.2.7 is an example of a concept map drawn from a food production system producing field crops (wheat, oats, barley, soybeans) and hogs for pork in Western France. Material for this concept map is drawn from Billen et al., 2012, "Localising the nitrogen footprint of the Paris food supply"¹

Text description of the Figure 1.2.7 image.

The image is a hand-drawn concept map illustrating the interaction between human systems and natural systems in global food production and distribution. The diagram is divided into two sections: Human (labeled in red on the left) and Natural (labeled in green on the right). On the human side, key elements include European consumers, global shipping, farm management knowledge, and food processing and distribution companies, which are linked to products such as meat products and baked goods. Arrows show relationships such as government regulation for food safety and the role of companies in supplying consumers. On the natural side, components include soybean farms (Brazil), good climate for farming, pigs and pig farms, crops and crop farms (wheat, oats, barley), and good soils and flat land. Environmental concerns are noted, such as overuse of manure and fertilizer pollution, and the impact on rivers, estuaries, and coastlines, with an emphasis on regulation of water pollution. The map uses arrows to demonstrate how natural resources and farming conditions support agricultural production, which then connects to human systems through shipping, processing, and consumption. This visual emphasizes the complex interdependence between environmental factors and human activities in sustaining global food systems.

Credit: Steven Vanek

3. Fill in the table on the worksheet with short answer responses regarding the two food systems you have chosen. The worksheet asks for responses in the following areas:
   1. Identify two natural components of the food system.
   2. Identify three human components of the food system.
   3. Tell how products from the system are transported to markets or to households for consumption.
   4. Name one sustainability challenge for the system, and state whether it represents a challenge in the area of environmental, social, or economic sustainability.

Once complete, use the worksheet as a guide to complete the Summative Assessment quiz.