America’s Largest Primate Faces Potential Loss of Up to 61% of Suitable Habitat by 2090

The two species of muriquis, northern muriqui (Brachyteles hypoxanthus) and southern muriqui (Brachyteles arachnoides), represent the largest genus of primates native to the Americas. These primates, endemic to Brazil’s Atlantic Forest, are facing alarming threats from climate change. A recent study published in the Journal for Nature Conservation meticulously quantifies the probable loss of climatically suitable habitats for these species over the course of the 21st century, projecting declines of 44% and 61% for the northern and southern muriqui respectively by 2090. The direst forecast highlights that in the state of São Paulo, the northern muriqui could lose its entire climatically favorable territory by century’s end.

This study’s projections exclusively consider climatic alterations, sidelining other critical pressures such as deforestation, fragmentation of the forest environment, and hunting pressures, all of which amplify the threat to these primates and their fragile habitats. Both species have been classified as “critically endangered” by the International Union for Conservation of Nature (IUCN), underscoring the critical urgency of their conservation. Tiago Vasconcelos, lead author of the study and researcher at São Paulo State University (UNESP), emphasizes that while climate change alone may not elicit extinction, it will severely contract the viable habitat, magnifying existing vulnerabilities from anthropogenic pressures.

The methodology employed in the study leverages advanced ecological modeling software. This software integrates current distribution data for muroquis with detailed climatic variables imperative for their physiological survival and reproduction, such as precipitation patterns, temperature ranges, and dry season intensity. By establishing the species’ current climate niches, the models extrapolate these requirements onto future climate scenarios, allowing predictions of habitat suitability transformations under varying climate projections spanning from 2030 to 2090.

Prior studies have broadly forecasted habitat loss by 2050 and 2090, but Vasconcelos’ research brings into focus the progressive nature of habitat contraction occurring steadily through the century. His projections illuminate how semi-deciduous forests, particularly in the interior regions of Paraná and São Paulo states—important western habitats for the southern muriqui—will shrink consistently without reprieve over decades. Moreover, an intriguing biogeographic shift is projected with the species’ range trending northeastward, counter to some other faunal groups that might gain new suitable areas elsewhere in response to warming climates.

However, this shift does not equate to habitat gain. The western extents of the species’ ranges are expected to diminish substantially, resulting in the southern muriqui’s populations becoming increasingly relegated to eastern forests. A similar pattern emerges for the northern muriqui, whose climatically suitable habitat is expected to dwindle most rapidly between the decades of 2070 and 2090. The primates’ stronghold areas will likely be confined to coastal zones characterized by ombrophilous rainforests, ecosystems rich in moisture and favorable for sustaining lush vegetation critical for muriqui survival.

The state of Minas Gerais and the central and western regions of Rio de Janeiro are predicted to witness significant losses in the northern muriqui’s suitable habitat, and São Paulo’s entire portion of climatically suitable range may vanish. By 2090, only two formidable climatically favorable areas might persist for the northern muriqui. One is projected in northern Bahia and northeastern Minas Gerais, and the other along the Espírito Santo coast extending slightly into northern Rio de Janeiro.

This looming reduction and redistribution engender profound implications for the species’ genetic diversity and long-term viability. Habitat loss coupled with forest fragmentation threatens population isolation, impeding gene flow and risking local extinctions, already documented in compromised semi-deciduous forests. The breakdown of connectivity between subpopulations is one of the most insidious consequences of environmental degradation, raising the specter of inbreeding depression and decreased resilience to environmental fluctuations.

The research underscores that climate change’s impacts cannot be viewed in isolation. Synergistic factors, including human-driven landscape changes, intensify the pressure on muriquis beyond what climate models alone demonstrate. Vasconcelos advocates for a convergence of conservation approaches that prioritize maintaining and restoring habitat corridors. These ecological linkages would facilitate movement and genetic exchange, ensuring the persistence of these primates in an increasingly fragmented forest matrix.

Particular conservation emphasis should target coastal rainforests where large, climatically suitable habitats for muriquis are anticipated to persist deeper into the century. Identifying optimal sites for ecological corridors is crucial to connecting isolated populations now separated by habitat loss and fragmentation. These corridors not only enable gene flow but also allow the species to track shifting suitable climate zones as they evolve under climatic transformations.

In summary, while climate change alone presents a formidable challenge for muriquis, the compound threats of ongoing deforestation, land use change, and hunting amplify extinction risks. Comprehensive, interdisciplinary conservation strategies are urgently needed. These strategies must integrate climate adaptation frameworks with habitat protection, restoration, and connectivity initiatives, creating resilient landscapes where muriqui populations can endure and thrive.

Tiago Vasconcelos’ study, underpinned by rigorous climate modeling and field research, provides vital temporal and spatial detail about increasingly restricted habitats. It forms a pivotal scientific foundation for policy-makers, conservationists, and environmental planners focused on safeguarding Brazil’s iconic muriquis and the ecological integrity of the Atlantic Forest hotspot.

The findings were supported by the São Paulo Research Foundation (FAPESP) through its Research Program on Global Climate Change (RPGCC), reflecting the essential role of dedicated funding in advancing ecological knowledge to inform urgent conservation actions. As our planet’s climate rapidly evolves, studies such as this highlight the imperative to understand species-specific vulnerabilities and to craft adaptive strategies that might yet secure their future existence.

News Publication Date: 18-Jul-2025

Web References:
– https://www.agencia.fapesp.br/53161
– http://dx.doi.org/10.1016/j.jnc.2025.127019