Perturbations and shocks are common in food systems and involve both the “natural system” components and the “human system” components in these systems. Throughout modules 11.1 and 11.2, we will use the word shocks and perturbations fairly interchangeably to refer to these negative events that challenge food systems and their proper function, although the word "shock" denotes a perturbation that is more sudden and potentially disastrous. Perturbations and shocks in “natural” components include dramatic changes in climate factors such as rainfall, as well as changes brought on by biological components such as disease and pest outbreaks that affect plants and livestock. Similarly, perturbations can occur within the “human system” components of a system. For instance, food prices are rarely entirely constant and farmers and consumers are said to face "price shocks" in the purchasing of food.

Figure 11.1.1. A photo of an Andean agroecosystem during the long dry season shows how water limits food production in some parts of the Andes. This system is thus very vulnerable to drought shocks, and its vulnerability is compounded by shallow, eroded soils that result from cultivating sloped land. These soils store less water than under their original vegetation cover and are thus more vulnerable.

Credit: Steven Vanek

Figure 11.1.2. This photo of dramatic flooding in Wisconsin, United States shows conditions of near certain crop failure or damage to pastures for these fields, which is a strong negative shock to local food production and farmer livelihoods. Farmers may, however, be somewhat buffered from economic hardship if they have crop insurance, and food security for local inhabitants may be buffered by movement and sales of food from elsewhere in the regional and global food system.

Credit: United States Federal Emergency Management Agency, used with permission through a Wikimedia Commons creative commons license.

Extreme conditions can result in major perturbations and shocks in agri-food systems. Major climate variation, such as severe or prolonged drought, is a common example with regard to major changes emanating from the natural system (see figure 11.1.1). Gary Paul Nabhan, the author of the required reading in this module, uses the example of the extreme "Dust Bowl" drought in the United States in the 1930s. Since it is already a region that receives little rainfall, the agri-food systems in the U.S. Southwest were considerably threatened by this drought. Extreme conditions endangering food-growing and availability can also arise in human systems. Examples include political and military instability as well as market failures and volatility (such as the sharp increase in prices).

The human-environment dynamics of major perturbations and shocks in agri-food systems are shown in figure 11.1.3. This figure uses the already familiar approach of Coupled Natural-Human Systems (CNHS) introduced in Module 1 and applied in module 10 and throughout the course. Here we apply it to interactions of the natural and human systems that result in reduced production and accessibility of food. The human response to perturbations and shocks can be understood by applying the CNHS framework to agri-food systems. Within this diagram, we also want to emphasize that because of the coupling and interactions within and among these systems, the human and natural systems are never just passive recipients of a shock. Both subsystems have mechanisms for responding that can either ameliorate or worsen the "crisis" effects of perturbation. These system properties and responses to shocks are considered through the concepts of resilience, adaptive capacity, and vulnerability (RACV), defined on the next page. In the next module (11.2) we will use the RACV and human-natural systems framework to understand shocks and system responses that result in famine and severe malnutrition.

Figure 11.1.3. The framework of Coupled Natural-Human Systems (CNHS) applied to Perturbations and Shocks in Agri-Food Systems. For both the human and natural systems, the characteristics and internal interactions of each will determine properties of resilience versus vulnerability, which influences what the final effect of a shock or perturbation will be. The internal interaction arrow of the human System is given a larger size, at center left of the image, to describe human-generated shocks such as conflict or economic crises (as well as their human mitigating factors in the form of preparedness or food aid, e.g.) can have in improving or worsening the impacts of shocks. Natural to human coupling is conceived of both as drivers and feedbacks because shocks that may seem to originate purely in the natural system, such as droughts and flooding, are increasingly understood to be feedbacks or responses to the damaging effects of human systems on natural systems such as soil erosion or climate change.

Credit: Karl Zimmerer, adapted from the National Science Foundation.

Introductory Video and Knowledge Check

Please watch the brief video about resilience and adaptive capacity. The presenter, Terry Chapin of the University of Alaska- Fairbanks, is an ecosystem ecologist who is used to thinking about the stresses that whole systems like ecosystems and food systems confront. Note that he uses the term 'resources' as roughly equivalent to the components of natural systems that support coupled human-natural food systems presented on the previous page. After the video in the knowledge check activity below, we'll ask you to identify the types of resources (i.e. components of natural systems) we've presented as vital to food systems in this course. You should, therefore, think about how the example he presents of Alaskan Native American communities and peoples can extend to many other elements of the food system.

Video: Resilience: The importance of adaptive capacity (2:10)

Knowledge Check Activity

Based on your learning in the course so far:

Definitions of Resilience, Adaptive Capacity, and Vulnerability

Resilience, adaptive capacity, and vulnerability (RACV) are three concepts used to explain how human and natural systems respond to perturbations and shocks. We can use these concepts to understand the responses of agri-food systems to such factors as drought or the occurrence of market shocks or political crises. Here are some definitions of the RACV concepts, understood within a Coupled Natural-Human System Framework.

Resilience

Resilience is a system property which denotes the degree of shock or change that can be tolerated while the system maintains its structure, basic functioning, and organization. Talking about resilience usually implies thinking about the resilience “OF what TO what”. That is, we need to understand the resilience of a system (what system or process?; e.g. crop production; food distribution; farming or culinary knowledge) TO a threat or shock (what kind?; e.g. drought, war, plant disease). A recent report from a United Kingdom scientific commission states that resilience is “the capacity to absorb, utilize or even benefit from perturbations, shocks and stresses” which includes the idea that resilient systems, provided they are sufficiently robust, can even benefit from perturbations.

Figure 11.1.4. A farmer-educator with a Peruvian NGO at a “knowledge fair” describes strategies to adapt to climate change and resulting weather shocks that are being evaluated and promoted by a local non-governmental organization in conjunction with indigenous communities. The poster behind the promoter describes how organic matter in the soil helps to retain moisture to adapt to drought shocks.

Credit: Steven Vanek

Adaptive Capacity

Adaptive capacities are the social and technical skills and strategies of individuals and groups that are directed towards responding to environmental and socioeconomic changes. In the context of food systems, adaptive capacity is usually exhibited or deployed to maintain livelihoods, food production, or food access. In the context of climate change, it is important to distinguish between adaptive capacity vs. mitigation: Adaptive capacity is deployed to adapt to perturbations in growing or living conditions or shocks brought on by climate change. Mitigation involves actively reducing the threat of climate change, rather than adapting to its effects: for example reducing emissions, reducing meat consumption among high-meat consuming populations, or geoengineering of the atmosphere to reduce CO₂ concentrations.

Adaptive capacity is the second important property that refers to the responsiveness of agri-food systems when faced with extreme conditions. Human systems might, for example, have the capacity to switch to alternative land use within the agri-food systems. In these cases, people would be able to adapt to change since they have the capacity to shift their use of land and other resources. Adaptive capacity in the case of natural systems is exemplified by drought-tolerant crops (figure 11.1.5). Such crops may have more developed root systems or biological adaptations for conserving moisture.

Figure 11.1.5. The Andean lupine, Lupinus mutabilis, pictured here in Bolivia, has a deep root system, superior ability to acquire its own nitrogen for protein from the air, and drought-adapted physiology that allows it to survive and produce lupine beans well into the dry season. It is also a highly nutritious and versatile food crop for consumption and income generation, once bitter alkaloids have been removed from the beans. It thus forms part of a human adaptive capacity in the local agri-food system to a dry climate and drought.

Credit: Paul VanDerWerf, Flickr

Vulnerability

Vulnerability is the exposure and difficulty of individuals, families, communities, and countries in coping with shocks, risk, and other contingencies. This can be thought of as the opposite of adaptive capacity, with a continuum of mixed adaptation/vulnerability in between the two extremes of adaptive capacity and vulnerability. Farmers and consumers in extremely poor and isolated circumstances (whether in urban or remote areas) can be considered highly vulnerable because they lack their own ability to adapt to threats, and may be cut off or marginalized from external resources (family, government assistance etc.) that allows them to adapt to changes.

Now we can apply the concepts of resilience, adaptive capacity, and vulnerability to agriculture and food, using a Coupled Natural-Human System (CNHS) framework (Figure 11.1.6)

Figure 11.1.6. Examples of Resilience (R), Adaptive Capacity (AC), and Vulnerability (V) in coupled agri-food systems. These examples are shown interior to each of the human and natural systems. Many of the positive practices regarding soils, water, and pests in the previous modules of the course can be considered additional examples of adaptive capacity because they contribute to greater levels of resilience to shocks, in addition to increasing or maintaining production under average conditions.

Click for a text description of the Resilience, Adaptive Capacity, and Vulnerability examples image.

Examples of Resilience (R), Adaptive Capacity (AC), and Vulnerability (V) in Human systems and natural systems

Human Systems:

R: Social infrastructure and social learning

AC: Alternative land use and crops, social assistance

V: Extreme poverty

Natural Systems:

R: Biotic diversity and healthy soils

AC: Tolerance to extremes of diverse crops, insect, and soil biota and well structured soils

V: homogeneity of seeds, eroded and low organic-matter soils

Credit: Karl Zimmerer and Steven Vanek

As shown in Figure 11.1.6, resilience can be found in both the natural and human subsystems of food systems. You may recognize that many of the examples of natural system adaptive capacity refer to the "best practices" that we have advocated for water, soils, crops, and pest management in sections II and III of this course. These would include examples such as reducing the water footprint of food production, managing soils in a system framework for greater "soil health", and managing pests with ecological practices that seek to avoid pest and weed resistance to our management approaches (Modules 4, 5, 7, and 8 respectively). These approaches are not only important in increasing productivity under average conditions, but also help a food production system to adapt to shocks and perturbations.

Meanwhile, the human component of coupled human-natural food systems also is a vital part of resilience and adaptive capacity. Resilience is higher where there are higher levels of social infrastructure that enable people to share learning and resources in response to shocks and perturbations, such as extreme drought. Social infrastructure, shown in Fig. 11.1.6, includes mutual assistance within families and communities or among regions in a country, coordinated by governments to assist in the case of shocks that affect food production. Social learning is vitally important since it’s one of the main ways that people would learning new techniques based on the conditions prevailing in their area. For example, farmers could use social learning to acquire the skills and knowledge to lessen water use, and thereby lessen the degree of agricultural production decline and reduced food access. Biological diversity is a major example of higher resilience functioning in the natural components of coupled agri-food systems. Food production systems with more biological diversity---a property referred to as agrobiodiversity and covered on the next pages---typically have the capacity for greater levels of resilience. This greater level of resilience may result from a mixture of crops and varieties combining vulnerable and resistant type of crop, for any given stress, so that even if some crops fail, others will do well. Different crops and land uses may also produce positive or facilitating interactions in which one crop type or wild plant species, for example, provides benefits to another (e.g. nitrogen fixation and better soils or screening from an important pest; see module 6 on crops and the previous section on systems approaches for management for additional examples).

Resilience vs. Adaptive Capacity: What's the Difference?

On the surface, resilience and adaptive capacity in systems may seem very similar, and it is true that as defined here they are very aligned. One way to remember the difference is that resilience is a broader system property that may have to do with the interplay of human and natural systems, or one or the other of these subsystems. We can say that a region's food system is quite resilient to drought (a more general statement) if we think for a number of reasons that its food supply would be able to continue mostly without issues during a drought. Adaptive capacity meanwhile is more narrowly focused on the specific skills and mechanisms that are deployed by human systems to contribute to resilience. In other words, we might identify that the system or component thereof is resilient (like the region mentioned above), and then identify sources or mechanisms of resilience in terms of particular knowledge, practices, land uses, or biological properties that are functioning in a food production system, referring to these as adaptive capacity. We turn next to agrobiodiversity as an example of adaptive capacity that can contribute to food system resilience (can you see the difference between the two words in this last sentence?).

One major way of increasing the resilience and adaptive capacity of agri-food systems in response to perturbations and shocks is to be certain they contain components with high levels of agrobiodiversity.

Here is a standard definition of agrobiodiversity:

Agricultural biodiversity…includes the cornucopia of crop seeds and livestock breeds that have been largely domesticated by indigenous stewards to meet their nutritional and cultural needs, as well as the many wild species that interact with them in food-producing habitats. Such domesticated resources cannot be divorced from their caretakers. These caretakers have also cultivated traditional knowledge about how to grow and process foods.. (which) is the legacy of countless generations of farming, herding and gardening cultures.

This definition is taken from Gary Nabhan’s book Where Our Food Comes From and is based on work of the United Nation’s Food and Agriculture Organization (FAO)

Figure 11.1.7. A farmer-educator working with a Peruvian Non-Governmental Organization (NGO) presents several dozen native potato varieties from the department of Cuzco, Peru. In addition to showing the ingenuity of local potato selection and breeding by farmers, these varieties are part of a rich cultural heritage and social infrastructure, and a facet of adaptive capacity via agrobiodiversity.

Credit: Steven Vanek

There are two important points to note about this definition:

• First, and most importantly, the biological diversity of agri-food systems includes vital coupling to the human system, most directly the people who are growers and their skills, knowledge, and other factors. These growers are “caretakers” in Nabhan’s definition; see Fig. 11.1.7 for potato varieties and a representative "caretaker" - a local farmer with working knowledge of these varieties. Agrobiodiversity exists squarely at the intersection of human and natural systems conceptualized in this course.
• Second, it encompasses both our cultivated species of plants and animals, which are crops and livestock chosen and evolved for production, as well as their still living wild relatives and the biodiversity of the ecosystems associated with this production (both the agroecosystem itself and the surrounding uncultivated ecosystem). Agrobiodiversity production in the natural system must be sufficient to offer positive feedbacks into the human system in order to offer the incentive for continued production.

The above-mentioned points in the definition of agrobiodiversity are illustrated in figure 9.6, which depicts agrobiodiversity as a Coupled Human-Natural System (CNHS).

Figure 11.1.8. Factors in human systems and natural systems commonly associated with active use of agrobiodiversity

Credit: Karl Zimmerer

The growers of agrobiodiversity range widely around the world. They include the people of traditional and indigenous cultures who often live in more remote locations. Many of these people live in mountainous regions and hill lands of the tropics and sub-tropics. Their use of agrobiodiversity in agri-food systems is reflected in certain global centers of diversity, as shown in the map that we presented in Module 2 regarding the sites of crop domestication in the early history of food systems. Such centers are sometimes called “Vavilov Centers” in recognition of the pioneering contribution of the scientist Nikolay Vavilov in the 1920s.

Figure 11.1.9. Global areas of concentrated agrobiodiversity corresponding to the Vavilov "centers of diversity" introduced in Module 2.

Credit: used with permission from the Wikimedia Commons project

Increasingly it’s recognized that significant agrobiodiversity also occurs outside the Vavilov Centers. For example, many urban and peri-urban dwellers grow small fields and gardens as part of local, small-scale agri-food systems. Producers of diversified production for local markets in North America and Europe are still another important group of agrobiodiversity-growers.

The extent of agrobiodiversity, in terms of crops and livestock, may vary from only a few types in a field or farm to many dozens. Agri-food systems with only a few types are quite important since they can confer significant resilience to perturbations and stressors. For example, cultivation of only a few types of barley, wheat, or maize (“corn” in the U.S.) among neighboring farms and communities can offer a much higher degree of resilience than the monoculture of a single type.

Figure 11.1.10. A sampling of the many present-day native varieties or landraces of barley from that crop's center of domestication in Ethiopia.

Credit: Used with permission under a creative commons license from the Global Crop Diversity Trust

Equally important is the case of the megadiverse agri-food systems. In the potato fields of the Andes Mountains of western South America, for example, a farmer may grow as many as 20-30 major types of potatoes in a single field. (Figure 11.1.11). Here, in tha global “Vavilov Center” of the Andes mountains, high levels of agrobiodiversity are integral to the agri-food system as a result of factors in the human system (skills, knowledge, labor-time, cultural and culinary preferences) and the natural system (highly varied climate and soil conditions characteristic of tropical mountains).

Figure 11.1.11. Nearly 70 varieties of Andean potatoes in a local agri-food System in the Peruvian Andes

Credit: Karl Zimmerer

Activate Your Learning: Agrobiodiversity and Resilience

Assigned Reading:

Please read the brief "introduction to the reading" below and then the following pages from Gary Nabhan's book "Where Our Food Comes From":

Nabhan, G.P. "Rediscovering America and Surviving the Dust Bowl: The U. S. Southwest ", p. 129-138, part of Chapter 9, Where Our Food Comes From: Retracing Nikolay Vavilov's Quest to End Famine. Washington: Island Press.

Introduction to the reading: The reading describes part of a much longer account of travels by Vavilov (for whom the Vavilov centers of agrobiodiversity are named, see the previous page in the book, and module 2.1 in this course) from 1929 to 1934 in North America. During this trip, the Russian crop researcher met with U.S. researchers as well as "keepers" of U.S. native agrobiodiversity. This chapter describes Vavilov's trip to the Hopi Indians in 1930, in which he and the U.S. scientists were able to observe firsthand the seed systems and their resilience to the drought that was currently going on in the United States. The author of the book, Gary Nabhan, relates this account of the visit and then compares it to similar visits he made to the Hopi in the more recent past. This compiled history of seed systems and their relation to both human and natural system changes in the U.S. Southwest is a sort of case study, from which the assessment worksheet will ask you to draw conclusions.

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