Tropical forests are the global cornerstone of biological diversity, and store 55% of the forest carbon stock globally, yet sustained provisioning of these forest ecosystem services may be threatened by hunting-induced extinctions of plant-animal mutualisms that maintain long-term forest dynamics. Large-bodied Atelinae primates and tapirs in particular offer nonredundant seed-dispersal services for many large-seeded Neotropical tree species, which on average have higher wood density than smaller-seeded and winddispersed trees. We used field data and models to project the spatial impact of hunting on large primates by ∼1 million rural households throughout the Brazilian Amazon. We then used a unique baseline dataset on 2,345 1-ha tree plots arrayed across the Brazilian Amazon to model changes in aboveground forest biomass under different scenarios of hunting-induced large-bodied frugivore extirpation. We project that defaunation of the most harvest-sensitive species will lead to losses in aboveground biomass of between 2.5-5.8% on average, with some losses as high as 26.5-37.8%. These findings highlight an urgent need to manage the sustainability of game hunting in both protected and unprotected tropical forests, and place full biodiversity integrity, including populations of large frugivorous vertebrates, firmly in the agenda of reducing emissions from deforestation and forest degradation (REDD+) programs. T ropical forests worldwide store >460 billion tons of carbonover half of the total atmospheric storage (1)-and tropical forest conversion and degradation account for as much as 20% of global anthropogenic greenhouse gas emissions (2). Tropical forests are also the most species-rich ecosystems on Earth, yet the role of species interactions in stabilizing tropical forest dynamics and maintaining the flow of natural ecosystem services, including long-term forest carbon pools, remains poorly understood. Over 80-96% of all woody plant species in tropical forests produce vertebrate-dispersed fleshy fruits (3, 4), yet many large-bodied frugivore populations in tropical forest regions have already been severely overhunted (5), resulting in functionally "empty" or "half-empty" forests with subsequent disruptions in seed dispersal mutualisms (6). Indeed, the total forest area degraded by unsustainable hunting in the largest remaining tropical forest regions may exceed the combined extent of deforestation, selective logging, and wildfires (7,8). Even formally decreed forest reserves in remote areas have succumbed to population declines and local extinctions of large vertebrates (9, 10), yet the consequences of this pervasive defaunation process to the persistence of tropical forest ecosystem services remains poorly explored.Overhunting can amplify dispersal limitation in many largeseeded plant species relying primarily or exclusively on harvestsensitive large-bodied frugivores. The causal mechanisms through which hunting leads to altered phytodemographics-recruitment bottlenecks resulting from replacement of seedlings f...
Sand flies (Diptera: Psychodidae) are responsible for the transmission of protozoan parasites that cause leishmaniases. They are found predominantly in forests, but some species exploit environments that have been subject to deforestation and subsequent human colonization. Studies conducted in Brazil over the past 30 years show that some species are adapting to peri-urban and urban settings. We evaluated sand fly diversity and abundance in the rural settlement of Rio Pardo, Presidente Figueiredo Municipality, Amazonas State, Brazil. Settlement households were divided into four categories. These categories were determined by the human population density and the degree of deforestation in the immediate area. We used CDC light traps to sample the area surrounding 24 households (6 households in each category). Samples were taken on six occasions during September-November 2009 and June-August 2010. A total of 3074 sand fly specimens were collected, including 1163 females and 1911 males. These were classified into 13 genera and 52 species. The greatest abundance of sand flies and the greatest richness of species were observed in areas where human population density was highest. Our results show that changes in the human occupancy and vegetation management in rural settlements may affect the population dynamics and distribution of sand fly species, thereby affecting the local transmission of cutaneous leishmaniases.
Planning of conservation priorities has often taken mapped forest types as surrogates for biological complementarity. In the Brazilian Amazon, these exercises have given equal weight to each forest type as if they were all equally distinct. Here, we examine floristic similarity between forest types to assess the reliability of vegetation maps as a surrogate for canopy tree‐community composition. We analyzed floristic differences at the genus level between twelve Amazonian forest types using 1184 one‐hectare inventories of large trees with three complementary approaches. First, we compared a map of floristic composition, from a uni‐dimensional NMDS ordination of the inventories, with a map of coarser‐level forest types commonly recognized as distinct by classification systems across Amazonia. Using Mantel and means‐difference tests, we next examined the distance‐decay of floristic similarity for all paired samples and for the pairs drawn from within and between twelve more finely divided forest types. Finally, we examined the degree of floristic separation of each pair of the twelve forest types using non‐parametric analysis of variance. Maps of floristic composition and coarse‐level forest types were highly congruent. At the finer level of classification, similarity was only slightly higher when pairs were drawn from the same versus from different forest types. This was true for all geographic distances. Nonetheless, eighty percent of the 66 paired combinations of forest types were significantly different in the unreduced genus‐space and nearly half showed little or no overlap in a two‐dimensional ordination. Three types were most distinct from all others: white sand, seasonally dry, and bamboo‐dominated forests. Here, we show that forest types exhibit variable degrees of separation. For this reason, treating all fine‐level forest types as equally distinct results in poor representation of canopy tree beta diversity. We recommend explicitly considering the degree of floristic separation between all forest types – as presented here for Amazonian flora – as a way to improve the use of this biodiversity surrogate.
BackgroundThe Arc of Fire across southern Amazonia seasonally attracts worldwide attention as forests are cut and burned for agricultural expansion. These forests contain numerous wild relatives of native South American crops, such as peach palm.Methodology/Principal FindingsOur prospecting expeditions examined critical areas for wild peach palm in the Arc of Fire in Mato Grosso, Pará, Maranhão and Tocantins, as well as areas not previously examined in Amazonas and Amapá states. Recent digitization of the RADAM Brasil project permitted comparison among RADAM's parataxonomists' observations, previous botanical collections and our prospecting. Mapping on soils and vegetation types enabled us to hypothesize a set of ecological preferences. Wild peach palm is best adapted to Ultisols (Acrisols) in open forests across the Arc of Fire and westward into the more humid western Amazonia. Populations are generally small (fewer than 10 plants) on slopes above watercourses. In northern Mato Grosso and southern Pará soybean fields and pastures now occupy numerous areas where RADAM identified wild peach palm. The controversial BR-163 Highway is already eroding wild peach palm as deforestation expands.Conclusions/SignificanceMany of these populations are now isolated by increasing forest fragmentation, which will lead to decreased reproduction via inbreeding depression and eventual extinction even without complete deforestation. Federal conservation areas are less numerous in the Arc of Fire than in other parts of Brazilian Amazonia, although there are indigenous lands; these conservation areas contain viable populations of wild peach palm and require better protection than they are currently receiving. Ex situ conservation of these populations is not viable given the relative lack of importance of domesticated peach palm and the difficulty of maintaining even economically interesting genetic resources.
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