- Climate change will make the current ranges of most Amazon primates uninhabitable in the coming decades, forcing them to move.
- But primates face barriers to dispersal, such as rivers and deforestation, which can limit their ability to migrate.
- If species aren’t able to find new habitats, the populations, as well as the habitat they support, will suffer.
New research shows that without healthy forest corridors that allow animals to find new habitat, primates native to the Amazon basin will suffer as the impacts of climate change worsen.
Brazilian ecologists focused on 80 species of primates found only in the Amazon. They modeled the ability of these primates to move among habitats under different forest management conditions. Their results highlighted how important it is to preserve migration routes to ensure the survival of these species.
“Even if we start taking actions now to mitigate, prevent or avoid climate change, species will still need to move,” said Lilian Sales, an ecologist at the University of Campinas in Brazil and lead author of the study, published recently in Ecography.
The Amazon rainforest supports an astounding amount of biodiversity, and primates help maintain the species richness. By spreading the seeds of trees, primates facilitate the growth of forests that affect global processes like carbon storage and temperature regulation.
For decades, deforestation for cattle ranches and soya plantations has threatened the Amazon. Now, the added pressures of climate change endangers the existence of several Amazon primates. “It’s a deadly mixture,” said Sales.
A few of the species most at risk include Roosmalens’ dwarf marmosets (Callibella humilis), pied tamarins (Saguinus bicolor) and Maués marmosets (Mico mauesi).
To understand how the ranges of these species might shift, Sales and her colleagues created a model combining several factors: the current IUCN ranges of 80 primate species; predictions of habitat shifts from the Intergovernmental Panel on Climate Change; the ability of each species to migrate; and two Amazon basin land-management scenarios.
The team modeled four different dispersal scenarios. The first scenario assumed that primates could migrate freely without barriers. The second assumed that large rivers block certain species, especially smaller primates, from accessing new areas. The third and most realistic scenario combined the limitations of rivers with the barriers of deforestation. The fourth showed how the ranges of primates would grow or shrink if they were prevented from moving at all.
For each of these projections, the researchers modeled two outcomes that depend heavily on conservation policy: a “mitigation” development plan, in which deforestation halts and protected areas grow; and a “business-as-usual” plan, in which current development trends continue.
Without the ability to migrate, the current ranges of all 80 primate species shrank in both the mitigation and the business-as-usual models. When limited by both rivers and deforestation, the business-as-usual scenario led to decreased habitat ranges for 65 of the 80 species. In the mitigation scenario, the habitats of 47 species would still shrink.
Not all species will necessarily suffer, however. A few, such as Bolivian red howler monkeys (Alouatta sara) and Peruvian night monkeys (Aotus miconax), might actually increase their current ranges if allowed to move. Sales said the finding surprised her, “but also gave me a feeling of hope that maybe not everything is lost.”
Rafael Reyna-Hurtado, an ecologist at El Colegio de la Frontera Sur in Campeche, Mexico, who was not involved in the research, called the study “a great contribution.” The team’s modeling makes assumptions, Reyna said, but he thinks it points to an important conservation lesson. “Many times we are concerned with the species and conserving the species,” he said, “but we also need to preserve their ability to disperse.”
Most of the regions that primates will need to move through to reach suitable habitats are not protected. With deforestation rates accelerating and plans for wildlife corridors nearly nonexistent, the projected fates of Amazonian primates range from unclear to grim.
Sales urged decision makers to take climate change and habitat loss into account when discussing how best to conserve these rainforest residents. “The main message of this paper,” she said, “is that we need to think of landscapes that allow species to move.”
Sales, L. P., Ribeiro, B. R., Pires, M. M., Chapman, C. A., & Loyola, R. (2019). Recalculating route: dispersal constraints will drive the redistribution of Amazon primates in the Anthropocene. Ecography, 42(10), 1789-1801.
Erin Malsbury (@erinmalsbury) is a graduate student in the Science Communication Program at the University of California, Santa Cruz. Other Mongabay stories produced by UCSC students can be found at https://news.mongabay.com/list/ucsc/.