Conference Agenda

In 2013, the European Union Common Agricultural Policy introduced a set of compulsory greening measures in its subsidies scheme in order to achieve environmental goals. We analyse the impact of this reform, and particularly the definition of Ecological Focus Areas (EFA), on bird diversity in France. We match bird observations from the French Breeding Bird Survey (BBS) to parcel level information on agricultural land use and type of crops. We exploit the heterogeneous exposure of bird observation sites to the reform depending on their ex-ante extent of arable area in a continuous difference-in-differences approach. We find evidence of an increase in overall bird abundance after 2015 in sites with a higher ex-ante proportion of arable land, driven by a small number of generalist species, and no impact on species richness and phylogenetic diversity. A decomposition by diet type suggests that vertebrate eaters were positively impacted by the reform.

By contrast, cropland species experienced the most dramatic decline after 2015 in sites with a higher share of arable area. Estimations of the dynamic effects of the reform suggest that the observed positive effects of the reform on bird abundance were limited to the first two years after its implementation. Based on observational data, our findings confirm previous concerns regarding the effectiveness of the 2013 reform in preserving biodiversity.

North America has lost nearly three billion birds since 1970, with grassland obligates ac counting for the steepest decline at 53% (Rosenberg et al., 2019). While ecological studies have attributed these losses to habitat conversion and pesticide exposure, the role of upstream economic drivers (in particular trade policy) has not been causally established. This paper exploits the staggered Canada-US (CUSFTA, 1989) and US-Mexico (NAFTA, 1994) agricul tural tariff elimination schedules, with crop-specific zero-tariff dates spanning 1990 to 1998 on the relevant bilateral margin. Combining stop-level Breeding Bird Survey data on 838 sites with a Bartik-style continuous exposure measure and a Sun-Abraham staggered difference-in differences estimator, we identify the effect of trade-induced crop reallocation on local avian bio diversity. We find that NAFTA exposure caused a 4 to 9% decline in local species richness over five years, rising to 10 to 12% in areas dominated by the soybean cohort. Effects are concen trated on grassland obligate species; generalist species, which would be the most direct margin for a pesticide-mediated channel, show no significant response. This habitat-specific pattern, combined with a contemporaneous-only pesticide response that fades within three years, iden tifies land-cover simplification rather than chemical intensification as the operative mechanism. The findings establish the first causal estimate of an agricultural trade liberalization’s effect on local avian diversity in a developed exporting economy, identified through the staggered tariff phase-out of NAFTA/CUSFTA.

How do large disruptions to ecosystems affect human well-being? This paper tests the long‐standing hypothesis that China's 1958 Four Pests Campaign, which exterminated sparrows despite scientists’ warnings about their pest‐control role, exacerbated the Great Famine—the largest in human history. Combining newly digitized data on historical agricultural productivity in China with habitat suitability modeling methods in ecology, we find that, after sparrow eradication, a one‐standard‐deviation increase in sparrow suitability led to 5.3% larger rice and 8.7% larger wheat declines. State food procurement exacerbated these losses, resulting in a 9.6% higher mortality in high‐suitability counties—implying nearly two million excess deaths.

We examine the impact of Ethiopia’s Agricultural Commercialization Clusters (ACC) program on farm input investment, production outcomes, market access, food consumption, and land-use change. Exploiting spatial and temporal variation in the rollout of ACC and applying a doubly robust difference-in-differences estimator, complemented by event-study analyses and high-resolution remote-sensing data, we assess both household-level and landscape-level responses to the program. We find that ACC leads to large and significant increases in agricultural input investment, including fertilizers, seeds, and improved seeds, alongside substantial gains in total agricultural output. Despite observable production gains, we find more limited evidence of short-run increases in market sales, implying that commercialization effects may not materialize immediately. Instead, households appear to absorb a substantial share of the additional output through increased own-consumption, reducing reliance on food purchases while maintaining overall food security. At the same time, ACC induces significant land-use change. Treated areas experience marked cropland expansion accompanied by forest loss, with effects persisting over time. We do not find corresponding improvements in remotely sensed indicators of vegetation productivity, implying that output growth is achieved primarily through input intensification and extensive-margin expansion rather than gains in per-hectare productivity observable from space. Our findings imply that large-scale commercialization initiatives can effectively stimulate investment and production at scale but may also generate unintended environmental trade-offs in the absence of complementary land-use governance and sustainable intensification measures.