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Pre-Columbian soil fertilization and current management maintain food resource availability in old-growth Amazonian forests
Full text linkAims: The extent and persistence of pre-Columbian human legacies in old-growth Amazonian forests are still controversial, partly because modern societies re-occupied old settlements, challenging the distinction between pre- and post-Columbian legacies. Here, we compared the effects of pre-Columbian vs. recent landscape domestication processes on soils and vegetation in two Amazonian regions. Methods: We studied forest landscapes at varying distances from pre-Columbian and current settlements inside protected areas occupied by traditional and indigenous peoples in the lower Tapajós and the upper-middle Madeira river basins. By conducting 69 free-listing interviews, participatory mappings, guided-tours, 27 forest inventories, and soil analysis, we assessed the influences of pre-Columbian and current activities in soils and plant resources surrounding the settlements. Results: In both regions, we found that pre-Columbian villages were more densely distributed across the landscape than current villages. Soil nutrients (mainly Ca and P) were higher closer to pre-Columbian villages but were generally not related to current villages, suggesting past soil fertilization. Soil charcoal was frequent in all forests, suggesting frequent fire events. The density of domesticated plants used for food increased in phosphorus enriched soils. In contrast, the density of plants used for construction decreased near current villages. Conclusions: We detected a significant effect of past soil fertilization on food resources over extensive areas, supporting the hypothesis that pre-Columbian landscape domestication left persistent marks on Amazonian landscapes. Our results suggest that a combination of pre-Columbian phosphorus fertilization with past and current management drives plant resource availability in old-growth forests. © 2020, The Author(s)
Improvement of the bioaccessibility of bioactive compounds from Amazon fruits treated using high energy ultrasound
No full textReview of the new world genus acrotaphus townes, 1960 (Hymenoptera: Ichneumonidae: Pimplinae), with descriptions of fifteen new species
No full textAcrotaphus Townes, 1960 is a moderately large New world genus of spider attacking parasitoid wasps. Previously, it comprised 11 species. The present study aims to review the genus, and includes descriptions of 15 new species: A. amajari sp. n., A. amazonicus sp. n., A. bodoquenaensis sp. n., A. cuzconus sp. n., A. dolichopus sp. n., A. homeofranklini sp. n., A. jackiechani sp. n., A. kourou sp. n., A. micrus sp. n., A. monotaenius sp. n., A. nambilloensis sp. n., A. pseudoamazonicus sp. n., A. pseudomexicanus sp. n., A. venezuelanus sp. n. and A. zampieronae sp. n.. In addition, we present new characters for the study of the genus and describe the male genitalia for the first time. An illustrated key and maps to the species of the genus are provided. Acrotaphus franklini Gauld, 1991 and A. pseudoamazonicus sp. n. were recorded from the nests of Trypoxylon (Trypargilum) lactitarse Saussure, 1867 (Hymenoptera: Crabronidae). © 2020 Magnolia Pres
Higher rates of liana regeneration after canopy fall drives species abundance patterns in central Amazonia
No full textIn tropical rainforest, most vascular plants have some capacity to resprout, and lianas are often effective resprouters after canopy fall. However, the diversity of resprouting responses of liana species and the consequence for plant persistence are poorly understood. We hypothesized that variation in regeneration among liana species causes differences in liana species abundance in tropical rainforest through differential resprouting capacity, such that liana species with higher densities produce more resprouts after canopy falls. We applied a manipulative field experiment investigating the effect of different levels of disturbance on the production of resprouts and adventitious roots in 10 liana species of the tribe Bignonieae (Bignoniaceae) with contrasting abundances in central Amazonia. We selected 15 individuals of each species and assigned the lianas to three distinct conditions: (a) total canopy fall with lianas severely damaged and detached from trees; (b) partial fall of lianas, without visible damage; and (c) intact lianas (control). We tested whether liana species regeneration patterns were related to species density. Liana species density was calculated using previous research on liana species distribution in 30 1-ha plots systematically distributed in a 6 × 6 km2 grid at the Ducke Reserve. The number of aerial resprouts produced by lianas under the total canopy fall treatment was twice that of plants under lower levels of disturbance, while the production of adventitious roots did not differ among treatments. Liana species showed different intensities of resprouting, and species with higher average densities on the forest landscape had more resprouts after the total canopy fall treatment. Synthesis. Our results shed new light on the factors that influence liana species abundance, highlighting the role of resprouting after canopy fall and its variation among liana species. Resprouting mitigates the negative effects of canopy damage, suggesting that the impact of increased tree fall disturbances over time, which has been attributed to Amazonian forests in the literature, may increase already abundant liana species with effective resprouting capacity. We identify liana species that are more resilient to disturbance and may alter forest dynamics during climatic change. © 2020 British Ecological Societ
A principal component analysis approach to assess CHIRPS precipitation dataset for the study of climate variability of the La Plata Basin, Southern South America
No full textThis article assesses the consistency of the satellite precipitation estimate CHIRPS v.2 to describe the spatiotemporal rainfall variability in the La Plata Basin (LPB), the second largest hydrographic basin in South America, by (a) pixel-to-point comparison of CHIRPS data with 167 observed monthly precipitation time series using three pairwise metrics (coefficient of correlation, bias and root mean square error) and (b) principal component analysis (PCA) to evaluate the large-scale coherence between CHIRPS and rain gauge data. The pairwise metrics indicate that CHIRPS better represents the rainfall in the coastal, northeastern and southeastern parts of the basin than in the Andean region to the west. The PCA shows that CHIRPS describes most of the observed rainfall variability in the LPB, but contains more variability, especially during December–February and March–May seasons. The two major modes observed are highly correlated spatially (empirical orthogonal functions—EOFs) and temporally (principal components—PCs) with the corresponding CHIRPS modes. The PCA allows the determination of the main rainfall variability modes and their possible relations with climate variability modes. Besides, the analyses of the precipitation anomaly modes show that the El Niño Southern Oscillation explains the first EOF modes of datasets. The PCA provides an alternative and effective means of assessing the consistency of CHIRPS data in representing spatial and temporal rainfall variability in the LPB. © 2020, Springer Nature B.V
Author Correction: A global database for metacommunity ecology, integrating species, traits, environment and space (Scientific Data, (2020), 7, 1, (6), 10.1038/s41597-019-0344-7)
No full textFollowing publication of this Data Descriptor it was found that the affiliation of Oliver Purschke was stated incorrectly. The correct affiliations are stated below: Department of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 37, SE-223 62 Lund, Sweden Biodiversity, Department of Biology, Lund University, Sölvegatan 37, SE-223 62 Lund, Sweden This has been corrected in both the HTML and PDF versions. © 2020, The Author(s)
Biochar Yield From Shell of Brazil Nut Fruit and Its Effects on Soil Acidity and Phosphorus Availability in Central Amazonian Yellow Oxisol
No full textEvolutionary units delimitation and continental multilocus phylogeny of the hyperdiverse catfish genus Hypostomus
No full textWith 149 currently recognized species, Hypostomus is one of the most species-rich catfish genera in the world, widely distributed over most of the Neotropical region. To clarify the evolutionary history of this genus, we reconstructed a comprehensive phylogeny of Hypostomus based on four nuclear and two mitochondrial markers. A total of 206 specimens collected from the main Neotropical rivers were included in the present study. Combining morphology and a Bayesian multispecies coalescent (MSC) approach, we recovered 85 previously recognized species plus 23 putative new species, organized into 118 ‘clusters’. We presented the Cluster Credibility (CC) index that provides numerical support for every hypothesis of cluster delimitation, facilitating delimitation decisions. We then examined the correspondence between the morphologically identified species and their inter-specific COI barcode pairwise divergence. The mean COI barcode divergence between morphological sisters species was 1.3 ± 1.2%, and only in 11% of the comparisons the divergence was ≥2%. This indicates that the COI barcode threshold of 2% classically used to delimit fish species would seriously underestimate the number of species in Hypostomus, advocating for a taxon-specific COI-based inter-specific divergence threshold to be used only when approximations of species richness are needed. The phylogeny of the 108 Hypostomus species, together with 35 additional outgroup species, confirms the monophyly of the genus. Four well-supported main lineages were retrieved, hereinafter called super-groups: Hypostomus cochliodon, H. hemiurus, H. auroguttatus, and H. plecostomus super-groups. We present a compilation of diagnostic characters for each super-group. Our phylogeny lays the foundation for future studies on biogeography and on macroevolution to better understand the successful radiation of this Neotropical fish genus. © 2019 Elsevier Inc
Relações entre a ocorrência de raízes acima do solo e fatores individuais e ambientais na Reserva Florestal Adolpho Ducke
Full text linkDeterminants of the occurrence of buttress and stilt roots are still poorly understood.
The mechanical stability required to reach large heights requires increasing diameter, and thus
large construction costs that could be alleviated with reallocation of investments to support
structures. Stressful environmental conditions such as exposure to wind, gravitational load and
anchorage instability in shallow soils can place extra demands on the stability of trees. We here
investigate how tree individual and environmental properties interact to determine the
occurrence of support structures. Presence of buttress or stilt roots and tree diameter were
recorded on 8.415 trees from 35 1-ha plots in central Amazon. On 67 trees of two target species
distributed across topography, we also measured allometry and crown size. Proportion of
support structures at the plot level and probability of occurrence at the individual level were
modelled with multiple linear or logistic regressions, and boosted regression trees. The
proportion of buttressed trees was higher in valleys and plateaus and stilt roots were more
frequent in valleys, when more inclined. At the individual level, the probability of occurrence
of any support structure increased with tree diameter and in valleys. Within species, diameter
was the most important predictor of buttresses, but 30% of the species had varied and complex
interactions with terrain slope and elevation. Occurrence of support structures was more likely
on stout trees (lower H:D ratio), which had smaller crown areas. In summary, the most unstable
environments, here represented by valleys with waterlogged soils, selected for a higher
frequency of trees with support structures at the community level. However, coordinated
allometric relationships among stem size and crown size also influence the need of support
structures. Thus, support structures are not fixed species traits, their presence depending on
individual plant´s allometric relationships and the instability conditions imposed by
environmentOs determinantes da ocorrência de raízes tabulares e suporte ainda são pouco
compreendidos. A estabilidade mecânica necessária para atingir grandes alturas requer aumento
de diâmetro e, portanto, grandes custos para esse aumento poderiam ser atenuados com a
realocação de investimentos em estruturas de apoio. Condições ambientais estressantes, como
exposição ao vento, carga gravitacional e instabilidade de ancoragem em solos rasos, podem
gerar demandas extras à estabilidade das árvores. Aqui, investigamos como as propriedades
individuais e ambientais da árvore interagem para determinar a ocorrência de estruturas de
suporte. A presença de raízes tabulares ou suporte e o diâmetro das árvores foram registrados
em 8.415 árvores de 35 parcelas de 1 ha na Amazônia central. Em 67 árvores de duas espéciesalvo distribuídas pela topografia, também medimos a alometria e o tamanho da copa. A
proporção de estruturas de suporte no nível da parcela e a probabilidade de ocorrência no nível
individual foram modeladas com várias regressões lineares ou logísticas e árvores de regressão.
A proporção de árvores com raízes tabulares foi maior nos baixios e platôs e raízes suporte
foram mais frequentes nos baixios, quando mais inclinados. No nível individual, a
probabilidade de ocorrência de qualquer estrutura de suporte aumentou com o diâmetro das
árvores e nos baixios. Dentro das espécies, o diâmetro foi o preditor mais importante das raízes
tabulares, mas 30% das espécies tiveram interações variadas e complexas com a inclinação e
altitude do terreno. A ocorrência de estruturas de suporte foi mais provável em árvores robustas
(menor proporção H: D), que possuíam áreas de copas menores. Em resumo, os ambientes mais
instáveis, aqui representados pelos baixios com solos alagados, selecionaram uma maior
frequência de árvores com estruturas de suporte no nível da comunidade. No entanto, relações
alométricas coordenadas entre o tamanho do tronco e o tamanho da copa também influenciam
a necessidade de estruturas de suporte. Assim, raízes tabulares e suporte não são características
fixas da espécie, sua presença depende das relações alométricas de cada planta e das condições
de instabilidade impostas pelo ambient
What happens in the darkness? Seasonal variations in tropical benthic fish assemblages
No full textStudies of fish assemblages have demonstrated that the main channels of rivers contain ichthyofauna adapted to this environment. However, information regarding the effects of temporal and spatial variations on this ichthyofauna is scarce. Using data from benthic fish assemblages in a major tributary of the Amazon basin collected during two consecutive receding and two rising water seasons, we tested the hypothesis that there are marked variations in community composition between the receding and rising water seasons. An asymmetry in predictability was detected among samples from the receding and rising seasons. Predictability in terms of species composition was higher for receding than rising seasons. The continual disassembly and reassembly cycles (due to dispersal) of local communities across a spatially heterogeneous landscape could explain this difference. Depth and dissolved oxygen affected the distribution of some benthic fish species during the rising seasons. This study highlights the important contribution of marginal wetlands to the benthic ichthyofauna inhabiting the main channel of the Purus River, as well as other major Amazonian rivers. © 2020 CSIRO