Terrestrial mammal assemblages in protected and human impacted areas in Northern Brazilian Amazonia

Abstract

Mammal communities in the vicinity of human settlements are often subject to subsistence hunting and retaliatory killings. We used fourteen digital camera traps equipped with infrared triggers to sample the medium-sized and large mammal communities for ca. 34 (±1.64) days per site. Diversity was measured as both Shannon entropy and Fager´s number of moves (NMS), and dominance was quantified using the Berger-Parker index. We used Kruskall-Wallis tests to investigate if there were statistically significant differences in richness, diversity and dominance among the sites. At an overall sampling effort of 1,946 trap days we recorded 216 independent observations of a total of 20 species belonging to 17 genera and 15 families. Richness and diversity appeared to be determined by forest structure, since, independent of the level of human impact, the richest areas were those closest to the ombrophilous forests of southern Guyana shield, closest to central Amazonia, whereas the poorest were at those sites closest to the vegetation mosaics of central Guyana shield. The disappearance of Tayassu pecari from the impacted areas as well as higher relative abundances in the protected areas, albeit not significant, foresees a possible bleak future for the mammalian assemblages in the near future.

Tree reproductive phenology determines the abundance of medium–sized and large mammalian assemblages in the Guyana shield of the Brazilian Amazonia

“…Covariates of forest structure and productivity, such as stratification, floristic diversity, and phenology have been proposed as determinants of mammalian abundance (Malcolm, 1995;Gentile and Fernandez, 1999;Grelle, 2003;Marshall et al, 2014;Luna et al, 2017). Gadelha et al (2017), studying a primate community in a habitat similar to that in the current study, found a significant association between mammalian abundance, and absolute dominance of trees, number of clearings, and vegetation height.…”

“…It has been shown in our previous studies (Gadelha et al, 2017;Luna et al, 2017) that at the regional scale (Peterson et al, 2011), the abundance of the mammalian assemblages can be determined by the physical structure of forests, whether it be in highly-heterogeneous vegetation mosaics, such as in the northern part of the Guyana Shield, or the ombrophilous forests of the southern part, or a transition between them. Now, we have also shown that at the local scale (Peterson et al, 2011), forest structure and productivity, and more specifically food availability and its fluctuations, determined the abundance of the mammalian assemblages.…”

“…In northernmost Brazilian Amazonia, on the Guyana Shield, lies one of the poorest regions in the Amazon basin for mammalian species diversity. Within it, the poorest area overall is the central zone, where rainfall is low and the dry season protracted (Eisenberg and Redford, 1979;Emmons, 1984;Janson and Emmons, 1990;Mendes Pontes, 2004;Hoorn et al, 2010;Luna et al, 2017). Here the vegetation is a mosaic of campinas (open, scrub vegetation), campinaranas (forests with short thin trees that stand in irregular, floodable terrain), and seasonally-dry to dry forests (Mendes Pontes et al, 2012).…”

“…Studies of medium-and large-sized mammals in northernmost Brazilian Amazonia are relatively recent and the focus has been mainly on the mammals of protected areas, such as Maracá Ecological Station (Nunes, 1992;Mendes Pontes, 1997Fragoso, 1998;Mendes Pontes et al, 2007), and the Waimiri-Atroari (Mazurek et al, 2000), Yanomami and Macuxi Indian reserves (Fragoso, 2004), although most recently, Melo et al (2015) and Luna et al (2017) studied the impacts on mammal assemblages of recent fishbone human settlements in Roraima state. It was revealed in these studies that the abundance of terrestrial mammal species can be greater than those of the arboreal ones, and that larger species can be more abundant than the smaller ones.…”

Nitrogen pulses increase fungal pathogens in Amazonian lowland tropical rain forests

“…Studies of mammals in Amazonia have shown carnivores and ungulates to be the most species‐rich orders in protected forest reserve areas surrounded by intact forests, while rodents and Xenarthra (anteaters, armadillos and sloths) may replace ungulates in reserves inserted in an anthropised landscape (Luna et al, 2017 and references therein), the ADFR being one such reserve (Table S1). There have been 42 species of medium‐ and large‐sized mammal species reported from the ADFR (Pontes et al, 2008).…”