Wish you were here: How defaunated is the Atlantic Forest biome of its medium- to large-bodied mammal fauna?

Abstract

Mammals represent the largest-bodied elements of the world’s surviving megafauna and provide several key ecosystems services, yet their populations are often under steep decline throughout the tropics. Anthropogenic defaunation is one the most important contemporary threats to modern mammal faunas. Although the Atlantic Forest biome of South America shows several clear signs of defaunation, the extent to which this biome has lost its mammal fauna remains poorly understood. Here, we collate and analyze a comprehensive body of secondary data to quantitatively assess the spatial patterns of defaunation of all medium- to large-bodied Atlantic Forest mammals which were then classed by morpho-ecological traits. We used a Defaunation Index, which was scaled-up to the entire biome using kriging interpolation, to examine the integrity of site-specific mammal faunas. We further use environmental and socioeconomic predictors to explain the drivers of defaunation. Our results show high levels of defaunation (>0.5) for most of the Atlantic Forest. Apex predators, other carnivores, large-bodied mammals and large herbivores were among the most defaunated functional groups. Remaining native vegetation cover, forest fragment size, and the largest neighboring forest remnant were the main negative predictors of defaunation. We conclude that medium- to large-bodied Atlantic Forest mammals are under high levels of threat due to historical population losses that continue today. A conservation action plan thus becomes imperative to prevent this biome from becoming an even “emptier forest”, severely compromising patterns of diversity, ecological processes and ecosystem functioning.

Co‐declining mammal–dung beetle faunas throughout the Atlantic Forest biome of South America

“…The present-day collapse of the Atlantic Forest mammal fauna is unprecedented, given a myriad of anthropogenic threats (Canale et al 2012, Bogoni et al 2018. We investigated the mammal influence on dung beetle richness, composition, abundance, body size and potential detritivore food web interactions.…”

“…Currently, only 11.7% (~16 377 472 ha) of its original vegetation cover remains, most of which consisting of highly disturbed forest remnants smaller than 50 ha (Ribeiro et al 2009). The scale of local extinctions of medium-to large-bodied mammals from the 1500s to the 2010s has exceeded 70% of all species (Bogoni et al 2018). The scale of local extinctions of medium-to large-bodied mammals from the 1500s to the 2010s has exceeded 70% of all species (Bogoni et al 2018).…”

Seed dispersal effectiveness by a large‐bodied invasive species in defaunated landscapes

“…Defaunation processes, the loss of animal species—especially large‐bodied vertebrates—due to anthropogenic causes (mainly habitat loss and overhunting, Dirzo et al., ), act synergistically with habitat loss and fragmentation to constrain seed dispersal services. Small‐bodied ground‐foraging frugivores are resilient to defaunation and fragmentation and persist in disturbed landscapes (Bogoni, Pires, Graipel, Peroni, & Peres, ). Some of these smaller‐bodied species, such as Corvid birds (Pesendorfer, Sillett, Koenig, & Morrison, ) and carnivorans such as canids and mustelids (González‐Varo, López‐Bao, & Guitián, ), are effective in connecting plant populations between isolated habitat fragments, but many fruit‐eating species cannot swallow seeds above a modest size threshold or do not have sufficiently large ranges to connect fragments of habitats (Cramer, Mesquita, & Williamson, ).…”

“…However, to determine the role of this non‐native species as a seed disperser in defaunated and fragmented landscapes, a thorough analysis of their interaction patterns, interaction frequencies, seed viability after ingestion, and characteristics of the seed shadows they produce is required. Given the large body size of wild pigs, which can weigh an average of 89 ± 31 kg as adults (F. Pedrosa, unpublished data), and resilience of populations to overharvest (Bieber & Ruf, ), we hypothesized that wild pigs may be capable of restoring seed dispersal services to fragmented systems that are widely defaunated (Bogoni et al., ).…”

End of the line for the golden lion tamarin? A single road threatens 30 years of conservation efforts

“…Habitat loss due to anthropogenic activities is a major cause of population decline and extinction of species (Bogoni, Pires, Graipel, Peroni, & Peres, 2018;Haddad et al, 2015). One of the negative effects of habitat loss is the reduction in connectivity between habitat patches as these become smaller and more isolated, limiting species access to key resources such as food or reproductive partners (Fahrig & Merriam, 1994;Hanski, 1998;Kremen & Merenlender, 2018).…”