(Beyond pesticidesApril 13, 2022) Combined effects of insect pollination and natural pest control provided by birds synergize to improve yields and incomes for coffee farmers, research finds published this month in the journal PNAS. Ecosystem services – the positive benefits provided by ecosystems, wildlife and their natural processes – underpin agricultural production, but are often analyzed in silos, on a case-by-case basis in the scientific literature. Current research reveals that the quantitative benefits of ecosystem services may be greater when considering their interactive effects. “Until now, researchers have typically calculated nature’s benefits separately and then simply added them together,” says lead author Alejandra Martínez-Salinas, PhD of the Center for Research and Higher Education in Tropical Agriculture (CATIE ) from Costa Rica. “But nature is an interactive system, full of important synergies and trade-offs. We show the ecological and economic importance of these interactions, in one of the first experiments at realistic scales in real farms.
The researchers based their experiment in Costa Rica, working with 30 shade-grown coffee farms owned by small landowners. Eight coffee plants from each farm were selected for the study. The pest control services provided by birds were assessed using a 20 mm mesh screen that excludes birds but allows bees and other pollinating insects to forage. Bee pollination was analyzed by choosing four comparable branches from each of eight coffee plants and using nylon mesh bags to exclude bees during flowering on two of the four branches. With this design, scientists were able to assess bird activity alone, pollination activity alone, bird and bee activity combined, and no bird or bee activity.
The impacts of these services were assessed on fruit set, fruit eight and the economic value of producing a coffee farm. With each of these measures, ecosynergy, a synergy between ecological services, produced the greatest benefit. While bird activity alone did not increase fruit set or weight, bee activity alone caused a modest average increase of 11% in fruit set and 4.2% in beet weight. fruits. Combined bird and bee activity shows the highest fruit set and fruit weight of all scenarios, with a 24% increase in fruit set and a 6.6% increase in fruit weight.
Increased fruit weight and fruit set meant greater economic benefits for coffee farms. The researchers estimated that farmers typically received around US$4,300 per hectare. The results of the experiment show that excluding birds reduces yield by 13.5%, representing a loss of almost $600 per hectare. The loss of bees in the landscape reduces yield by 24.5%, or a loss of $1,059 per hectare. The loss of birds and bees results in the highest yield and economic loss at 24.7%, representing a variance of $1,066.
“These results suggest that past assessments of individual ecosystem services – including major global efforts like IPBES – may in fact underestimate the benefits that biodiversity brings to agriculture and human well-being,” says Taylor. Ricketts of the University of Vermont. “These positive interactions mean that ecosystem services are more valuable together than apart.”
The study highlights the importance of preserving, maintaining and enhancing biodiversity and on-farm ecosystem services as a key aspect of considering agricultural yields. These services are essential, but more vulnerable than we think. For example, research published in 2015 by some of the same scientists in the current study found that only a small number of bee species actually provide pollination services, making their continued existence crucial for sustainability and conservation. long-term operating profitability. A study published in 2016 found that the loss of microbial diversity in soil impairs ecosystem services associated with decomposition, nutrient cycling and carbon sequestration, all critical roles needed to sustain food production. The 2019 report from the United Nations’ IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services) issues a stark warning to the world about how declining biodiversity is affecting society’s ability to respond to basic needs. But as the authors of this study note, even these dire calls may underestimate the benefits humanity derives from natural services, those we often take for granted.
Time and time again, research has shown that increasing on-farm biodiversity decreases the need to use pesticides (by increasing natural pest control services) and improves overall productivity. This is why organic farming represents the best approach for the future of agriculture. A central element of organic law is the requirement to maintain or improve soil health. From this concept stems the spirit and intent of organic agriculture to continually improve and promote natural materials and processes over toxic synthetic substances. These field practices, according to the Rodale Institute’s long-running farming systems trial, result in more organic matter and better soil health, yields competitive with chemical-intensive practices, 3 to 6 times higher agricultural profits and much lower greenhouse gas emissions and chemical use.
The benefits of natural systems are difficult to determine without a much greater investment in the type of research conducted as part of this study. As the author notes, the available literature on synergies between ecosystem services is particularly thin and needs more time and attention. For a review of the importance of biodiversity and ecosystem services to food production and our current way of life, see the articles “Organic Systems The Path Forward” and “Biodiversity in Land Management Integral to Sustainability”, published in the Pesticides and you log.
All unattributed positions and opinions in this article are those of Beyond Pesticides.