Recalculating route: dispersal constraints will drive the redistribution of Amazon primates in the Anthropocene

Abstract

Climate change will redistribute the global biodiversity in the Anthropocene. As climates change, species might move from one place to another, due to local extinctions and colonization of new environments. However, the existence of permeable migratory routes precedes faunal migrations in fragmented landscapes. Here, we investigate how dispersal will affect the outcome of climate change on the distribution of Amazon's primate species. We modeled the distribution of 80 Amazon primate species, using ecological niche models, and projected their potential distribution on scenarios of climate change. Then, we imposed landscape restrictions to primate dispersal, derived from a natural biogeographical barrier to primates (the main tributaries of the Amazon river) and an anthropogenic constraint to the migration of many canopy‐dependent animals (deforested areas). We also highlighted potential conflict zones, i.e. regions of high migration potential but predicted to be deforested. Species response to climate change varied across dispersal limitation scenarios. If species could occupy all newly suitable climate, almost 70% of species could expand ranges. Including dispersal barriers (natural and anthropogenic), however, led to range expansion in only less than 20% of the studied species. When species were not allowed to migrate, all of them lost an average of 90% of the suitable area, suggesting that climate may become unsuitable within their present distributions. All Amazon primate species may need to move as climate changes to avoid deleterious effects of exposure to non‐analog climates. The effect of climate change on the distribution of Amazon primates will ultimately depend on whether landscape permeability will allow climate‐driven faunal migrations. The network of protected areas in the Amazon could work as ‘stepping stones’ but most are outside important migratory routes. Therefore, protecting important dispersal corridors is foremost to allow effective migrations of the Amazon fauna in face of climate change and deforestation.

Climate and land‐use change will lead to a faunal “savannization” on tropical rainforests

“…Dispersal across fragmented landscapes will probably not safeguard forest‐specialists from exposure to non‐analog climates (Ribeiro et al., 2016), because their climate‐driven dispersal routes an be disrupted by deforestation (Lawler et al., 2013). Therefore, in addition to reducing and splitting habitat amount, ongoing and forecasted land‐use changes might prevent species from moving toward newly suitable environments, as the climate changes (Sales et al., 2019).…”

Frugivore-fruit size relationships between palms and mammals reveal past and future defaunation impacts

“…Hence, they may be less able to evolve to keep pace with changes in body-size composition of frugivore assemblages. Furthermore, many natural ecosystems have either already suffered the complete loss of large-vertebrate seed dispersers 21 , 53 or may have reduced their abundance, geographic range, or movement (e.g., through habitat fragmentation) to such a degree that the ecosystem functions they provide may be effectively lost (i.e., functional extinction) 61 – 64 .…”

Climate change drives spatial mismatch and threatens the biotic interactions of the Brazil nut

“…We caution, however, that defaunation associated with forest loss and fragmentation can lead to local extirpation of agoutis (Jorge, 2008), impairing seed dispersal and seedling recruitment, as has been observed elsewhere (Galetti et al, 2006). In addition, dispersal constraints not incorporated here, such as rivers and/or paved roads, may further prevent agouti occupancy of newly available habitat in the future, as has been forecasted for other mammals in the Amazon (Sales et al, 2019).…”

“…Tree cover also provides habitat and migratory routes for forest fauna (Sales et al, 2019). Deforested cells can pose barriers to the movement of animals, preventing climate-driven dispersal (Tucker et al, 2019).…”