The global target to protect 30% of the planet by 2030 (30 × 30 agenda) necessitates assessing the implications for competing land uses and rural communities. While the importance of socio-economic impacts is recognized, analyses focusing on multiple outcomes to assess environmental and socio-economic trade-offs are scarce. Studies comparing different protection arrangements relative to a range of specific alternative land uses are extremely limited. These gaps hinder policymakers' ability to understand and balance trade-offs in conservation and development decisions. This study aims to contrast environmental and socio-economic outcomes of different protection arrangements (strict protected areas (SPAs), sustainable-use PAs (SUPAs), and Indigenous territories (ITs)) with those from alternative land uses (sparsely populated areas, different agricultural landholding sizes, and mining concessions) in the Brazilian Legal Amazon (BLA). The BLA serves as a valuable case study due to its biodiversity, deforestation threats, contested land claims, and publicly available environmental and socio-economic data. Deforestation initially peaked in the early 2000s due to soy and cattle production but decreased after 2004 with government interventions. However, deforestation increased again since 2012, highlighting the ongoing competition for land. The study period (2000-2010) was chosen due to data availability from population censuses.

Existing literature acknowledges the significance of socio-economic impacts of protected areas, but comprehensive analyses assessing multiple outcomes and comparing different protection arrangements against a range of alternative land uses are limited. Studies highlighting the impacts of protected areas on poverty, inequality, and other dimensions of well-being exist, but often lack a comparative analysis of alternative land use scenarios. Research on the effects of different types of protected areas and their management regimes on deforestation and local livelihoods also provides a basis for the current study, suggesting a range of potential synergies and trade-offs. The impacts of large-scale agriculture and mining on deforestation and local poverty are also areas of focus in the existing literature, highlighting the importance of differentiating these competing land uses.

This study compiled a high-spatial-resolution, longitudinal dataset of land use, deforestation, and poverty for 5,545 census tracts (CTs) in the BLA between 2000 and 2010. Deforestation estimates were derived from the PRODES dataset, and poverty indicators (fiscal income, income inequality, literacy, and sanitation) came from population censuses. The study compared treated CTs (those becoming protected after 2000) with unprotected control CTs representing specific alternative land uses. Agricultural controls were categorized based on dominant landholding size (very small, small, medium, large). Mining controls were defined based on licensed mining activities. Statistical matching and regression techniques were used to control for potential confounders (biophysical, socio-economic, and political factors). Robustness checks included stricter matching criteria, different spatial definitions of protection, sensitivity analyses, and alternative modeling frameworks. The study employed a quasi-experimental approach, acknowledging limitations in drawing definitive causal claims from observational data.

All protection arrangements reduced deforestation compared to non-protected areas. ITs showed the greatest deforestation reduction (-69.0%), followed by SPAs (-53.6%) and SUPAs (-46.7%). However, ITs had smaller income increases (24.8% lower than matched controls) than SPAs (59.3% higher) and SUPAs (no significant difference). No significant relationships were found between protection arrangements and income inequality or sanitation. SUPAs were associated with higher literacy rates. Compared to agricultural land uses, SPAs and SUPAs reduced deforestation (except for SUPAs compared to very small landholders). ITs showed significant deforestation reduction compared to all agricultural land uses. SPAs were associated with larger income increases compared to medium and large agricultural landholders. ITs showed smaller income increases compared to sparsely populated areas and areas dominated by very small and large landholders. SUPAs showed mixed effects on income inequality. All protection arrangements reduced deforestation from mining, but SUPAs showed lower income gains, and ITs higher income inequality compared to mining areas. Robustness checks validated the main findings.

The study's findings highlight the effectiveness of ITs in reducing deforestation, emphasizing the conservation benefits of recognizing Indigenous land rights. However, socio-economic trade-offs exist for ITs, with lower income increases and, in some cases, lower literacy rates compared to other land uses. The limited effectiveness of SUPAs in reducing deforestation relative to very small landholdings suggests a need to consider land use transitions and consolidation risks when designing conservation strategies. The positive environmental and socio-economic outcomes of SPAs and SUPAs relative to large agricultural landholdings support the conclusion that large agricultural business development may not provide substantial socio-economic benefits to local populations. While all protection arrangements reduced deforestation from mining, socio-economic trade-offs were observed for SUPAs and ITs, emphasizing the importance of considering spatial scale when balancing environmental protection and socio-economic goals.

This study provides valuable insights into the environmental and socio-economic outcomes of different protection arrangements, particularly emphasizing the conservation effectiveness of ITs while highlighting the need for targeted development programs to support Indigenous communities. The findings underscore the importance of considering alternative land uses and potential trade-offs when planning PA expansion, suggesting a need for context-specific strategies and interventions. Further research is needed to understand the spatial extent of protection effects and potential deforestation displacement.

The study’s observational nature prevents definitive causal claims. The analysis focuses on legal mining concessions, neglecting the impact of illegal mining. The use of 2006 agricultural census data for the entire 2000–2010 period is a limitation. The study’s focus on the Brazilian Legal Amazon limits the generalizability of the findings to other regions. While efforts were made to account for various confounding factors, the possibility of unmeasured confounders influencing the results remains.