Quantifying the Spatial Footprint of Agriculture‐Driven Edge Effects in a Global Deforestation Hotspot

TL;DR

Agricultural expansion in the Argentine Dry Chaco causes strong edge effects that degrade forests up to 700 meters deep, leading to long-term ecological damage.

Contribution

Quantifies agriculture-driven edge effects in a deforestation hotspot using satellite data and Bayesian modeling, revealing their long-term and spatially extensive impacts.

Findings

Agricultural edge effects penetrate over 700 meters into forests, reducing tree and shrub cover and biomass by up to 41%.

Cropping causes stronger edge effects than ranching, with silvopastures showing significantly lower impacts.

Edge effects intensify for decades after deforestation, degrading 18% of remaining forests and causing a 92.3 million ton loss in aboveground biomass.

Abstract

Tropical dry forests are under high and rising pressure from agricultural expansion, resulting in widespread forest conversion and fragmentation. Additionally, remaining forests experience a range of edge effects through agriculture once it has been established, yet such agriculture‐driven edge effects remain weakly understood. Focusing on the Argentine Dry Chaco, a global hotspot for deforestation, we utilized satellite‐based forest structure indicators within a Bayesian Hierarchical Modelling framework to quantify and map agricultural edge effects on fractional tree and shrub cover, and aboveground biomass. Specifically, we assessed how far edges reach into forests away from the forest‐agriculture interface, whether edge effects differ among post‐deforestation land uses (i.e., cropping vs. ranching), and how edge effects evolve over time. We reveal large agriculture‐driven edge effects in the Chaco, penetrating > 700 m into adjacent forests, with reductions of up to 41% in our structural parameters. Cropping was associated with much stronger edge effects than pastures, likely due to the combined effect of environmental (e.g., wind) and management (e.g., pesticide drift) factors, while silvopastures had much lower edge effects. Projecting our models across the region showed that 18% of remaining forests are degraded, with an estimated total loss of 92.3 million tons of aboveground biomass. Lastly, agriculture‐driven edge effects intensified for long periods after initial deforestation (e.g., > 30 years for tree cover), suggesting agricultural expansion creates a degradation debt that unfolds over decades. We conclude that agriculture‐driven edge effects are a major, yet often overlooked, consequence of agricultural expansion, leading to profound degradation far beyond the deforestation footprint. Despite their importance, these effects remain systematically underestimated in sustainability analyses, such as carbon accounting or biodiversity impact assessments. Our work supports views that conservation planning should prioritize large and contiguous forest patches to help maintain ecologically functional forests.

Tropical dry forests face increasing pressure from agricultural expansion, but how this expansion impacts on remaining forests is unclear. We quantified and mapped agricultural edge effects on tree cover, shrub cover, and above‐ground biomass in the Argentine Chaco, a global deforestation hotspot. Agriculture caused strong edge effects, especially for cropping. Edge effects intensified for decades after deforestation, creating a long‐lasting degradation debt. Overall, we estimate that edge effects have degraded 18% of remaining forests. Our results show that agricultural expansion drives substantial, often overlooked degradation far beyond the deforestation footprint.

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