More than Share-Spare Philosophies Needed

A Response to Breakthrough's Essay on Wildlife and Farmland

There should be little disagreement regarding the benefits of diversity in ecosystems. Ecological theory and science have long since established that diverse ecosystems are robust and resilient to outside influences and shocks. In agricultural systems, lack of diversity has, at times, been implicated in susceptibility to climatic changes and pest or disease infestations ending in crop losses or even widespread crop failures. In this light, the article by Linus Blomqvist exploring the relationships between biodiversity and the balance of agricultural land sharing and land sparing is well taken. In broad strokes, these concepts are appealing, each in its own way, allowing for biodiverse ecosystems to coexist or commingle with agricultural production. With closer inspection, however, we believe there are limitations to these concepts.


Defining and measuring biodiversity is difficult. On the empirical side, the issue has primarily been studied in agricultural systems by using a few macroinvertebrate groups such as lepidoptera (i.e., butterflies, skippers, and moths), several bee species, and various types of beetles. More recently, great interest has emerged in the plant and soil microbiome (the microbial diversity associated with plants and agricultural soils), but overall, knowledge of diversity in many agricultural ecosystems is, thus far, relatively limited.

This limited scope restricts our ability to infer many potential impacts biodiversity may have, both within the agricultural system and outside of it. Indeed, it is possible that these two sub-ecosystems, one “natural,” the other human influenced, may not only be different, but may be at odds with each other. Unfortunately, the “ideal” state simply isn’t known for a vast majority of species for which conservation is important. For example, some migratory species may prefer small patches of habitat spread throughout a large range similar to what might be accomplished in a land-sharing approach. Other species may be favored by larger blocks of land set aside in a more natural state and might be favored by a more intensive land-sparing approach. And what works for some species may actually be detrimental to others.

Some organisms, like the European honey bee and some earthworm species, have become somewhat iconic species and are used—in the media if not in the scientific literature—as symbols of diversity in agriculture. But these species are, in fact, introduced to North America and can displace native species or cause environmental disruption outside the agricultural realm. Other species, like the milkweed plants relied upon by the beloved monarch butterfly, may actually be favored by agricultural practices. Some have posited that milkweed populations might even be much greater as a result of agricultural practices than could have been supported by the pre-agricultural native ecosystem. Similarly, there are places in Europe where land has been cultivated for so long that the agroecosystem must be protected to maintain the wildlife that exists in those habitats. Until we have a better understanding of the composition and interaction of agricultural bio-communities and those of the surrounding environment, it will be difficult to define the ideal balance between concepts such as land sharing and land sparing.

Another issue that needs to be addressed in these conversations is the concept of productivity and how it is measured. Typically, as here, productivity is measured as total output or yield per unit of land. This is particularly prevalent in the over-argued debate between organic and non-organic production systems. In that case, as well as with this comparison of land sharing or sparing philosophies, however, it is not the best metric for measuring productivity. We would argue that in addition to yield, product quality is equally valuable in assessing production systems. For producers, this is second nature. The wheat farmer, for example, regularly considers the protein content of their grain, the sugar beet farmer not only worries about their yield, but the sugar content of the beets as well, and so on. For the theorist, any system that optimizes yield, even in an environment with great biodiversity, will be of little use in land sparing/sharing if low product quality induces producers to maintain profitability through increased cultivation. For this reason, we would encourage any considerations of optimizing agricultural production to incorporate the dual characteristics of yield and quality.

The Bigger Problem

Agricultural activity is, by definition, a disruptive process. Even in a minimalist scenario, the simple husbandry of a plant or animal, whether native or introduced, is an alteration of the surrounding environment. The act of agriculture alters the world around us, sometimes in profound ways. Yet this process is necessary for our survival. It should be obvious to all parties, on all sides of the various debates, that we should then strive to carry out these activities in a manner that is not counterproductive to our current and future existence. To this end, we believe an agricultural system should aim to optimize the following characteristics, whether through land sharing, land sparing, or other concepts:

  1. Minimize input. As a matter of efficiency, agricultural production should use as few resources as possible. While this encompasses obvious inputs such as fertilizers, pesticides, and fuel, it should also be applied to other resources such as land use, labor, and money. When often-scrutinized inputs like fertilizer and pesticides are reduced, an increase in other inputs (like labor and fuel) nearly always results. The impacts of these trade-offs must also be considered.
  2. Minimize impact. In conjunction with inputs, agricultural systems should limit the degree of alteration or effect of alteration on the environment where possible. Disruption of environments can lead to destabilization of a given system, increasing the risk of system failure. Limiting impact also helps ensure the long-term viability of the system into the future.
  3. Maximize output. The goal of any agricultural system is to produce a useful product. Given the investment being made in the inputs and impacts above, it is desirable to get the best product possible from those resources. As mentioned above, however, this output should consider both quantity and quality.
  4. Maximize benefit. Consumers are obvious beneficiaries of any agricultural system, and as such, the system should produce products they require in an affordable manner. It would seem the majority of discussions on agricultural benefits often concentrate on the consumer side. The producers, however, occupy an equally important role in production benefits. Any agricultural system must provide benefits to the producer. Most notably, these benefits should take the form of economic returns, but also more nebulous considerations such as their quality of life and living conditions.

The first three of these criteria are addressable through further refinement of theoretical or scientific knowledge. Indeed, many of these topics have been, and are being, pursued. The arguments of Blomqvist regarding land sharing and sparing are certainly related to these items. Yet, even with these considerations, they seem inadequate. They may indeed be necessary, but are not sufficient. Through technological advances, there has been intensification of agricultural yield (and quality) of truly astonishing degrees over the 20th century. In spite of this, however, we have also seen marked increases in agricultural land use in the North American Midwest. European production has seen valiant efforts towards land sharing, yet this is accompanied by increased deforestation in the developing world, much of it aimed to supply the demand in developed countries. These concepts of land sharing or sparing have not, in themselves, resulted in desired outcomes. This is primarily due to more powerful forces outside the limited academic arguments of inputs and outputs, yields and efficiencies, and other tangible factors. In order to address the balance between agricultural land use and that of the natural world, we believe the final point above, particularly in terms of the producer, is vital to any discussion. Without inclusion of farmers, ranchers, and other producers in these discussions, no methodology, no matter how effective or desirable, will move forward in a lasting way.

While it is widely acknowledged that biodiversity is beneficial, we need a better understanding of what it means specifically for an agricultural system and the environments that surround it. We must also cope with the realization that ideal biodiversity on and off the farm may not be the same or even compatible. Furthermore, solutions will differ from farm to farm, year to year, and crop to crop. Most importantly, all the debates regarding conservation methods and philosophies must move beyond the academic sphere and incorporate the social and economic components that will inevitably be the determiners of their adoption or rejection. Only when all participants in the food system are on board can we have long-term, productive, conservation-minded policies in place that can weather social, economic, and political challenges.