Evaluating the ecological and climate contributions of indigenous lands under the Marco Temporal law in Brazil.

Indigenous lands play a leading role in conserving biodiversity and mitigating climate change, which is fundamental for Brazil and the world. However, the Marco Temporal law n° 14.701/23 argues that Brazilian indigenous peoples only have the right to demarcate lands that were in their possession or disputed at the time of the promulgation of the 1988 Constitution. To assess the possible impacts of the Marco Temporal law, we used Ecological Niche Modeling techniques to predict the distribution of endangered terrestrial vertebrates, evaluating the percentage of those species that are protected by Indigenous lands. Furthermore, we quantify the carbon stock in these areas using a spatially explicit model generated by the Random Forest algorithm developed within the MapBiomas Solo project. Our results confirm the importance of Indigenous lands in protecting biodiversity, hosting more than 85 % of Brazilian endangered terrestrial vertebrates. Furthermore, we highlight the relevance of these lands in combating climate change, having a significantly higher carbon stock than Brazilian conservation units. If applied, the approval of the Marco Temporal law could generate legal uncertainty, threatening the health of several Indigenous ethnicities and increasing conflicts due to land exploitation. To effectively fulfill international commitments to conserve biodiversity and mitigate climate change, the Brazilian government must make the demarcation and protection of Indigenous lands and guarantee the constitutional rights of original peoples a central political priority on its agenda. [Display omitted] • Indigenous lands are as effective as conservation units in protecting endangered species and climate change mitigation • The demarcation and protection of Indigenous lands guarantee Indigenous people's constitutional rights • The legal uncertainty in indigenous lands threatens biodiversity conservation, especially in the Amazon's arc of deforestation • Demarcating Indigenous lands helps Brazil meet international biodiversity conservation and climate change agreements. • Amazon's Indigenous lands effectively protect threatened terrestrial vertebrate species. [ABSTRACT FROM AUTHOR]