Are indigenous territories effective natural climate solutions? A neotropical analysis using matching methods and geographic discontinuity designs

Abstract

Indigenous Territories (ITs) with less centralized forest governance than Protected Areas (PAs) may represent cost-effective natural climate solutions to meet the Paris agreement. However, the literature has been limited to examining the effect of ITs on deforestation, despite the influence of anthropogenic degradation. Thus, little is known about the temporal and spatial effect of allocating ITs on carbon stocks dynamics that account for losses from deforestation and degradation. Using Amazon Basin countries and Panama, this study aims to estimate the temporal and spatial effects of ITs and PAs on carbon stocks. To estimate the temporal effects, we use annual carbon density maps, matching analysis, and linear mixed models. Furthermore, we explore the spatial heterogeneity of these estimates through geographic discontinuity designs, allowing us to assess the spatial effect of ITs and PAs boundaries on carbon stocks. The temporal effects highlight that allocating ITs preserves carbon stocks and buffer losses as well as allocating PAs in Panama and Amazon Basin countries. The geographic discontinuity designs reveal that ITs’ boundaries secure more extensive carbon stocks than their surroundings, and this difference tends to increase towards the least accessible areas, suggesting that indigenous land use in neotropical forests may have a temporarily and spatially stable impact on carbon stocks. Our findings imply that ITs in neotropical forests support Nationally Determined Contributions (NDCs) under the Paris Agreement. Thus, Indigenous peoples must become recipients of countries’ results-based payments.

Community Managed Protected Areas Conserve Aboveground Carbon Stocks: Implications for REDD+

“…Agriculture suitability and market access conditions were used as spatial location covariates associated with carbon stocks dynamics in Petén (Guatemala) and Acre (Brazil) (Table 2). Elevation, slope, precipitation, and temperature were included as spatial location covariates involved in agricultural suitability, following previous quasi-experimental studies (Pfaff et al, 2014;Blackman, 2015;Blackman and Veit, 2018;Alejo et al, 2021). (Baccini et al, 2012(Baccini et al, , 2017(Baccini et al, , 2021 Elevation (m) and slope (deg.)…”

“…To estimate the spatial heterogeneity of the temporal effects, we used geographic discontinuity designs. Following and similar to Alejo et al (2021), the geographic discontinuity designs aimed to estimate the effect of Community Managed PAs boundaries on preserving carbon stocks and avoiding CO 2 -eq emissions (hereafter, spatial effects) relative to surrounding Other Lands, Sustainable Use PAs, and Strict PAs. These geographic discontinuity designs are based on two assumptions.…”

“…Particularly, we controlled for geographic distance by performing matching analyses throughout four buffer zones inside and outside the boundaries of Community Managed PAs: 0-1, 0-5, 0-10, and 0-15 km. We chose these distances based on previous studies showing that natural vegetation (Joppa et al, 2008) and carbon stocks (Alejo et al, 2021) increase inside the boundaries of PAs and stabilize at ∼15 km. Thus, when matching treatment and control observations in buffer zones 0-1 km, we included matches across a 2-km radius.…”

“…However, other studies (e.g., Bonilla-Mejía and Higuera-Mendieta, 2019), assess the role of PAs boundaries relative to their surroundings or the spatial effects to elucidate local land-use dynamics. Thus, estimating temporal effects alongside spatial effects may contribute to the integral assessment of PAs (Blackman et al, 2015;Alejo et al, 2021). Nevertheless, few studies evaluate the effectiveness of Community Managed PAs relative to different land tenures through temporal and spatial assessments.…”

“…Our study differs from previous research on PAs and quasiexperimental methods in multiple ways. Compared with studies that estimate the effectiveness of PAs using either Other Lands (e.g., Nelson and Chomitz, 2011;Alejo et al, 2021) or other PAs (e.g., Elleason et al, 2021) as counterfactuals, we estimate Community Managed PAs' effectiveness relative to multiple land tenures. Moreover, we explore this effectiveness temporarily and spatially on carbon stocks and avoided emissions, contrasting similar studies that usually explore one of these two approaches on deforestation (e.g., Miranda et al, 2016;Blackman and Veit, 2018;Bonilla-Mejía and Higuera-Mendieta, 2019;Baragwanath and Bayi, 2020).…”