26
Jul
Monoculture in Crop Production Contributes to Biodiversity Loss and Pollinator Decline
(Beyond Pesticides, July 26, 2019) The botanic denizens of wild and unmanaged lands typically comprise many different plant species. This is because nature abhors monocultures — the existence of a single kind of plant growing across some amount of territory. Yet, this is the dominant practice in modern agriculture, and brings with it a plethora of problems. One of them, emerging from an Argentinian study out of the Universidad Nacional del Comahue and published in Global Change Biology, is that agricultural production in some areas of the world is at risk because of this obeisance to monoculture in a time of biodiversity loss and pollinator decline.
Monocultural agriculture, for all its perceived advantages — in yield, routinization of management practices, ease of harvesting, and others related to technological tools — also involves significant downsides, including:
- robbing local ecosystems of natural systems of checks and balances, thus making monocrops more vulnerable to pests and diseases — which in turn usually means greater applications of toxic pesticides
- nutritional impoverishment of soil by reducing available nutrients, thereby inviting addition of synthetic, usually fossil fuel–based fertilizers and other inputs
- degradation of soils so that they retain moisture far less well and cause increased runoff of those chemical inputs, potentially contributing to algal blooms and anaerobic “dead zones” in nearby water bodies
- increased topsoil erosion
- plants’ increased development of resistance to pesticides, fueling the cycle of resistance, creation of new chemical treatments, which then generate more resistance, etc.
Human dependence on pollinators for one-third of foodstuffs is at the center of the Argentinian study’s concern, given the decline in pollinator, and especially both domestic and wild bee, populations. The trend in some regions to plant more pollinator-dependent crops without also increasing crop diversity is leading to greater demand for pollination services — which this study indicates is increasingly likely to be met by a shortfall of available pollinators. Increasing demand on these insects to pollinate crops — in the context of the larger “insect apocalypse” at hand — means a smaller proportion of such plants are pollinated. Therein lies the risk to production capacity.
In order to examine how agricultural expansion, diversity, and dependence on pollinators have interacted around the world in recent decades, the research team analyzed crop data from the Food and Agriculture Organization of the United Nations. During the 55 years prior to 2016, the researchers found that, worldwide, the aggregate land area cultivated with crops not dependent on pollinators increased by 17.3%, whereas the amount cultivated with pollinator‐dependent crops grew by 136.9%. The authors surmise that “the pollinator dependence of global agriculture, in terms of the proportion of area cultivated with pollinator‐dependent crops, increased by approximately 70%,” while crop diversity increased by only 20.5%.
The study reveals great variation in these dynamics, however, depending on region. For example, despite plenty of agricultural expansion on the African continent, there has been little rise in pollinator dependence because much of that expansion has been in non-pollinator-dependent crops. In Europe, such dependence has increased even in the face of decreasing amounts of land in cultivation because of intensification of pollinator-dependent crops.
Agricultural production is particularly at risk in regions of Brazil, Argentina, Paraguay, and Bolivia, due largely to increases in soybean cultivation. “Soy production has risen by around 30 percent per decade globally. This is problematic because numerous natural and semi-natural habitats, including tropical and subtropical forests and meadows, have been destroyed for soy fields,” says the study’s lead researcher, Marcelo Aizen, PhD. Some Asian countries, such as Indonesia and Malaysia face similar challenges because of growth in demand for the production of palm oil.
Habitat loss — largely due to human development activities, including agricultural expansion — is another chief contributor to significant declines in insect, including pollinator, populations. Particularly in subtropical and tropical areas, the clearing of forests for agricultural expansion is a huge concern; those parcels are often cleared in order to be planted with monocrops that promise high market return on investment. Commonly, soybean, nut, oilseed (such as rapeseed for canola oil and oil palm), and fruits crops are planted, and these require pollinators to produce the useful parts of the plant (technically, the fruit and seeds). The use of toxic pesticides plays a major role in pollinator decline; as Beyond Pesticides has covered comprehensively, pesticides present very significant threats to pollinators, and to human and environmental health, never mind the costs associated with the outcomes. As Environmental Health News notes, “A Cornell study found that pesticide use in the United States causes $520 million in crop loss and $1.1 billion in health costs.”
Although the global insect decline is caused primarily by pesticide use, habitat destruction, and climate change, monocropping represents an additional catalyst to this collapse. According to the study authors, shifts to more pollinator-dependent cropping, absent sufficient pollinator populations, can actually contribute to pollinator decline via pesticide use and natural habitat loss. “Farmers are growing more crops that require pollination, such as fruits, nuts and oilseeds, because there is an increasing demand for them and they have a higher market value. This study points out that these current trends are not great for pollinators,” said David Inouye, PhD, coauthor and professor emeritus of biology at the University of Maryland. As Beyond Pesticides has reported, shifting from monocropping to regenerative, organic, and sustainable practices can support, rather than destroy, biodiversity and pollinator population success.
The project team posits that the mismatch between increasing demand for pollinators and the lack of a commensurate increase in the diversity of what is being cultivated is concerning because of the social, economic, and environmental consequences that may ensue. The study authors say that further useful work might identify regions that are particularly vulnerable because steep increases in their pollinator dependence are taking a high environmental toll that is not offset by economic and other benefits.
The researchers emphasize that their study results represent an “alarm call for the implementation of more pollinator‐friendly, synergistic management, including targeted use of insecticides, the setting aside of marginal land to establish and maintain flower strips and hedgerows, and the restoration of semi-natural and natural areas adjacent to crops. Such changes, in addition to increasing crop diversity at different spatial scales, will increase farmland heterogeneity, fostering pollination services and thus agricultural productivity and sustainability.”
Beyond Pesticides lends its voice to the call for a shift in the destructive and antiquated agricultural system that continues to prevail in the U.S. — the huge growth in organic agriculture aside. Organic and regenerative practices help make their local ecosystems far more resilient to the threats of a warming planet and its more-extreme weather: healthy soil and cover crops, for example, help prevent nutrient and water loss, making land more able to withstand floods and droughts. As reported by The Rodale Institute, during droughts, organic parcels generate yields up to 40% greater than those of traditional, chemically fertilized plots treated with pesticides. In addition, organic practices — by forgoing the use of pesticides — support pollinators and eliminate much of the toxic burden to which they’re exposed in agricultural areas.
Everyone has a role to play in leveraging the shift away from our toxic “business as usual” approaches and toward a genuinely sustainability agroeconomy. As set out in the June 18, 2019 Beyond Pesticides Daily News Blog entry, “through public pressure and consumer choice, we can shift towards alternative products and practices, improve biodiversity, and begin to repair the damage done by industrial agriculture.”
Track pollinator, biodiversity, and organic agriculture developments with Beyond Pesticides’ multiplicity of tools, including its Daily News Blog and the journal Pesticides and You. Support its work by becoming a member and/or signing up to learn about actions to take in support of its mission.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Sources: https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.14736 and
https://www.ehn.org/monoculture-farming-is-not-good-for-the-bees-study-2639154525.html
