Agroecology: When Nature Returns to Guide Agriculture
Agroecology: When Nature Returns to Guide Agriculture
The emergence of the intensive agricultural model, beginning in the 1950s, led to a profound transformation of agroecosystems. Increasing crop specialization, the structural simplification of production systems, and the reduction of functional biodiversity led to a progressive departure from ecological equilibrium. Under these conditions, farms showed increased vulnerability to pests, pathogens, and abiotic stress, resulting in the massive use of synthetic pesticides.
The use of chemical molecules—insecticides, fungicides, herbicides, and rodenticides—has certainly helped stabilize yields and limit production losses. However, this approach has generated significant environmental externalities: contamination of environmental matrices (soil, water, air), accumulation of toxic substances along food chains, loss of biodiversity, and a weakening of ecosystem services. The functional simplification of agroecosystems has also favored the emergence of resistance in numerous target species, fueling a vicious cycle of increased treatments, loss of efficiency, and rising production costs.
A paradigmatic indicator of these dynamics is the progressive decline of insects, known in the literature as “insect decline” and, in popular culture, as the “windshield effect.” Recent meta-analyses have estimated an average decline rate of 2.5% per year, with overall values indicating approximately 40% of known species are in decline, while a third are threatened with extinction (Bahlai, 2019; Sánchez-Bayo & Wyckhuys, 2019). Regional studies have documented even more significant losses: a 75% decline in flying insect biomass in German nature reserves in 25 years, a 90% decline in the monarch butterfly population in North America in the last two decades, and a 58% decline in lepidoptera in English farmland in less than a decade (Dirzo et al., 2014).
The causes of this entomological collapse are multifactorial, with three main drivers:
Loss and fragmentation of natural habitats, due to both agricultural expansion and urban development;
Massive and persistent use of synthetic pesticides, which affect not only target insects but also beneficial insects and natural enemies, reducing trophic complexity;
Climate change, which alters the life and reproductive cycles of insects, compromising the physiological adaptation of populations (Bale et al., 2002; Sunday et al., 2012).
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The decline of insects has critical implications for ecosystem function. They are key elements in the processes of pollination, decomposition, and organic matter recycling, as well as representing a fundamental component of food chains. Even partial loss of these populations can lead to situations of “functional extinction,” with serious repercussions on the stability of ecosystems and the agricultural systems dependent on their services.
The consequences also directly affect human health. Numerous studies have documented the widespread presence of pesticide residues in food and human bodies, with higher concentrations in children than in adults (EEA, 2023). Such exposures have been linked to chronic diseases, including cancer, cardiovascular, respiratory, and neurological diseases. At the same time, the economic cost of reliance on synthetic molecules is growing: development of resistance, increased doses used, the need for new molecules, in addition to the indirect costs related to occupational diseases, poisoning, and production losses due to reduced pollination.
Available alternatives include biological and integrated pest management, which involve the use of natural ecological mechanisms (predation, parasitism, competition) and techniques with low environmental impact, with the goal of containing harmful populations within economically harmless thresholds, without pursuing eradication. Documented examples, such as the ecological management of rice in Asia, demonstrate how adopting agroecological approaches can drastically reduce pesticide use and increase yields, with long-term economic and environmental benefits.
In light of this evidence, it is clear that overcoming the current dependence on synthetic products cannot be achieved solely through mitigation techniques, but requires a shift in the production paradigm. It is necessary to transition to a model in which agricultural management is harmonized with ecological processes, valorizing functional biodiversity and ecosystem services as structural elements of the production system.
This model is represented by agroecology, understood as a scientific, practical, and political approach capable of integrating ecological principles, economic sustainability, and social equity. It represents the true “green revolution” of the 21st century, the only way to ensure resilience, sustainability, and food security for future generations.
Guido Bissanti