The jaguar is the top predator of the Atlantic Forest (AF), which is a highly threatened biodiversity hotspot that occurs in Brazil, Paraguay and Argentina. By combining data sets from 14 research groups across the region, we determine the population status of the jaguar and propose a spatial prioritization for conservation actions. About 85% of the jaguar’s habitat in the AF has been lost and only 7% remains in good condition. Jaguars persist in around 2.8% of the region, and live in very low densities in most of the areas. The population of jaguars in the AF is probably lower than 300 individuals scattered in small sub-populations. We identified seven Jaguar Conservation Units (JCUs) and seven potential JCUs, and only three of these areas may have ≥50 individuals. A connectivity analysis shows that most of the JCUs are isolated. Habitat loss and fragmentation were the major causes for jaguar decline, but human induced mortality is the main threat for the remaining population. We classified areas according to their contribution to jaguar conservation and we recommend management actions for each of them. The methodology in this study could be used for conservation planning of other carnivore species.
This study examined whether the population density and home range size of red‐rumped agoutis were affected by the spatial distribution of Brazil nut trees, at the Pinkaiti Research Station, in eastern Amazonia. Agouti densities in a Brazil nut grove were two‐fold higher and home ranges were half the size than those outside it. This indicates that the large supply of Brazil nuts results in higher densities and smaller home ranges of agoutis in this seasonally dry Amazonian forest.
Inter-specific competition is considered one of the main selective pressures affecting species distribution and coexistence. Different species vary in the way they forage in order to minimize encounters with their competitors and with their predators. However, it is still poorly known whether and how native species change their foraging behavior in the presence of exotic species, particularly in South America. Here we compare diet overlap of fruits and foraging activity period of two sympatric native ungulates (the white-lipped peccary, Tayassu pecari, and the collared peccary, Pecari tajacu) with the invasive feral pig (Sus scrofa) in the Brazilian Pantanal. We found high diet overlap between white-lipped peccaries and feral pigs, but low overlap between collared peccaries and feral pigs. Furthermore, we found that feral pigs may influence the foraging period of both native peccaries, but in different ways. In the absence of feral pigs, collared peccary activity peaks in the early evening, possibly allowing them to avoid white-lipped peccary activity peaks, which occur in the morning. In the presence of feral pigs, collared peccaries forage mostly in early morning, while white-lipped peccaries forage throughout the day. Our results indicate that collared peccaries may avoid foraging at the same time as white-lipped peccaries. However, they forage during the same periods as feral pigs, with whom they have lower diet overlap. Our study highlights how an exotic species may alter interactions between native species by interfering in their foraging periods.
This is the first study to investigate whether scatter-hoarding behavior, a conditional mutualism, can be disrupted by forest fragmentation. We examined whether acouchies (Myoprocta acouchy, Rodentia) and agoutis (Dasyprocta leporina, Rodentia) changed scatter-hoarding behavior toward seeds of Astrocaryum aculeatum (Arecaceae) as a consequence of a decrease in forest-patch area. Our study was conducted at the 30-year-old Biological Dynamics of Forest Fragments Project, in central Amazon, Brazil. We tested whether forest size affected the number of Astrocaryum seeds removed and scatter-hoarded (and likely dispersed) by acouchies and agoutis, as well as the distance that the seeds were hoarded. The study extended over three seasons: the peak of the rainy season (MarchApril), the transition between the rainy and the dry season (May-June), and the peak of the dry season (AugustSeptember). Our results revealed that the number of seeds removed was larger in smaller fragments, but that the percentage of seeds hoarded was much lower, and seeds eaten much higher, in 1-ha fragments. Moreover, fewer seeds were taken longer distances in fragments than in the continuous forest. Site affected the number of seeds removed and season affected the percentage of seeds hoarded: more seeds were removed from stations in one site than in two others, and hoarding was more important in April and September than in June. Our study reveals that scatter-hoarding behavior is affected by forest fragmentation, with the most important disruption in very small fragments. Fragmentation converts a largely mutualistic relationship between the rodents and this palm in large forest patches into seed predation in small fragments.
Much of what remains of the Earth's tropical forests is embedded within agricultural landscapes, where forest is reduced and fragmented. As native forest ungulates are critical to maintaining forest function, it is imperative to understand how this functional group responds to declines in forest cover and connectivity resulting from agricultural expansion. We addressed this issue by evaluating selection of forest cover and forest connectivity by a key native ungulate of Neotropical forests, the white‐lipped peccary (Tayassu pecari Link 1795, Tayassuidae, Cetartiodactyla), in agricultural landscapes of Brazil. We evaluated selection using compositional analysis at two hierarchical levels, landscape, and home range. From 2013 to 2019, we GPS‐tracked eight white‐lipped peccary herds in Southwest Brazil, resulting in a total of 14,460 GPS locations. We found that herds can live in landscapes with a wide range of forest cover (35%–81% of home ranges covered by native forest), with significant, but not strong, selection at the landscape level (p = .045). Nevertheless, herds strongly select for forest cover within their home ranges (81%–97% of locations within native forest; highly significant selection at the home‐range level: p = .008). As for connectivity, herds significantly select the largest, most connected forest fragments at the landscape level (p = .04), but not at the home‐range level (p = .07). Our results support that Neotropical forests within agricultural landscapes need to be well connected in order to preserve this key native ungulate and maintain long‐term forest function.
Abstract in Portuguese is available with online material.
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