Recent studies have leveraged large datasets from plot-inventory networks to report a phenomenon of hyperdominance in Amazonian tree communities, concluding that few species are common and many are ...rare. However, taxonomic hypotheses may not be consistent across these large plot networks, potentially masking cryptic diversity and threatened rare taxa. In the current study, we have reviewed one of the most abundant putatively hyperdominant taxa, Protium heptaphyllum (Aubl.) Marchand (Burseraceae), long considered to be a taxonomically difficult species complex. Using morphological, genomic, and functional data, we present evidence that P. heptaphyllum sensu lato may represent eight separately evolving lineages, each warranting species status. Most of these lineages are geographically restricted, and few if any of them could be considered hyperdominant on their own. In addition, functional trait data are consistent with the hypothesis that trees from each lineage are adapted to distinct soil and climate conditions. Moreover, some of the newly discovered species are rare, with habitats currently experiencing rapid deforestation. We highlight an urgent need to improve sampling and methods for species discovery in order to avoid oversimplified assumptions regarding diversity and rarity in the tropics and the implications for ecosystem functioning and conservation.
The harvesting of açaí berries (palm fruits from the genus
Euterpe
) in Amazonia has increased over the last 20 years due to a high local and global market demand and triggered by their widely ...acclaimed health benefits as a ‘superfood’. Although such increase represents a financial boom for local communities, unregulated extraction in Amazonia risks negative environmental effects including biodiversity loss through açai intensification and deforestation. Alternatively, the introduction of certified sustainable agroforestry production programs of açaí has been strategically applied to reduce the exploitation of Amazonian forests. Local açaí producers are required to follow principles of defined sustainable management practices, environmental guidelines, and social behaviors, paying specific attention to fair trade and human rights. In this study we investigate whether sustainable agroforestry and certification effectively promotes biodiversity conservation in Amazonia. To address this question, we conducted a forestry inventory in two hectares of long-term certified açai harvesting areas to gain further knowledge on the plant diversity and forest structure in açaí managed forests and to understand the contribution of certification towards sustainable forest management. On average, we found that certified managed forests harbor 50% more tree species than non-certified açaí groves. Trees in certified areas also have significantly higher mean basal area, meaning larger and hence older individuals are more likely to be protected. Certified harvesting sites also harbor dense populations of threatened species as classified by the International Union for Conservation of Nature (e.g.
Virola surinamensis,
classified as ‘endangered’). Besides increasing the knowledge of plant diversity in açaí managed areas, we present baseline information for monitoring the impact of harvesting activities in natural ecosystems in Amazonia.
A review of Neotropical Burseraceae Daly, Douglas C.; Perdiz, Ricardo O.; Fine, Paul V. A. ...
Revista brasileira de botânica,
03/2022, Letnik:
45, Številka:
1
Journal Article
Recenzirano
This review of Neotropical Burseraceae emphasizes developments since the last major review of the family in 2011. The Burseraceae comprise a Laurasian group (represented by Eocene fossils in the ...Northern Hemisphere) that originally dispersed through Central America into Amazonia. During cooling and drying events in the Oligocene, the frost-intolerant northern American progenitors were likely driven extinct; subsequently, the family experienced several vicariant events and later several long-distance dispersals across the Southern Hemisphere. From Amazonia, the family re-colonized Central America and the Caribbean. The most rapid diversifications in the Americas for the Burseraceae occurred during the Miocene in
Protium
and
Bursera
, much of it through geological events, dispersal, and habitat specialization. A number of taxonomic advances were made in Neotropical Burseraceae since 2011; these included 59 published new species overall, re-drawn generic limits in tribe Protieae, new genus records for Burseraceae in Central America and the
Cerrado
of Brazil, new taxa that more than doubled the number of Neotropical
Dacryodes
, and a recently recognized center of diversity for
Protium
in the Andes. Revised generic descriptions and a new key to the New World genera of Burseraceae are provided. Special attention is given to the implications of leaf architecture for characterization of clades. Monoecy (rare) and parthenocarpy (possibly frequent) are discussed, and the close relationship of dioecious trees and small bee pollination is highlighted. Most Burseraceae are dispersed by birds or arboreal mammals that carry pyrenes relatively short distances away from the mother tree; however, other modes are found in the family, including wind dispersal (rare in New World Burseraceae), clumped dispersal of pyrenes by ants and lizards, and oilbirds that can disperse
Dacryodes
fruits more than 30 km; some dispersers that ingest pyrenes also aid in germination. The diversity and abundance of Burseraceae in a number of regions and habitats (but especially in moist forests of Amazonia and dry forests of Mexico) are striking. This, plus the fact that the taxonomy and phylogeny of New World Burseraceae are relatively well-resolved, spotlights the Burseraceae as an important model organism for researching mechanisms of diversification, species limits, cryptic species, and “hyperdominance” in tropical forests. High chemical diversity and differences in biological activity make sense in the context of diversification and coexistence. Studies of chemical defenses support the idea of a “growth defense trade-off” and suggest that selection by different natural enemies could be implicated in the speciation process; they also show that closely related species often display high chemical divergence, and plants with the most chemical defenses have a lower number and diversity of insect herbivores. The range of physical and chemical properties of Burseraceae resin is reflected in their cultural uses, which are diverse while showing strong ethnobotanical convergence.
Plants in the Burseraceae are globally recognized for producing resins and essential oils with medicinal properties and have economic value. In addition, most of the aromatic and non-aromatic ...components of Burseraceae resins are derived from a variety of terpene and terpenoid chemicals. Although terpene genes have been identified in model plant crops (e.g.,
,
), very few genomic resources are available for non-model groups, including the highly diverse Burseraceae family. Here we report the assembly of a leaf transcriptome of
, an aromatic tree that has a large distribution in Central America, describe the functional annotation of putative terpene biosynthetic genes and compare terpene biosynthetic genes found in
with those identified in other Burseraceae taxa. The genomic resources of
can be used to generate novel sequencing markers for population genetics and comparative phylogenetic studies, and to investigate the diversity and evolution of terpene genes in the Burseraceae.
Processes driving the assembly of swamp forest communities have been poorly explored. We analyzed natural regeneration and adult tree communities data of a swamp gallery forest in Central Brazil to ...discuss the role of ecological filters in shaping plant species turnover in a successional gradient. Species data of 120 plots were used to assess species turnover between natural regeneration and adult tree communities. Our analyses were based on 4995 individuals belonging to 72 species. Community patterns were discerned using ordination analyses. A clear floristic turnover among plant life stages was distinguished. Regeneration community of swamp forests was richer in species composition than the adult community. Tree species commonly found in nonflooded gallery forests were present in the regeneration plots but not in the adult community. Differences in the floristic composition of these two strata suggest that not all species in the seedling stage can stand permanent flooding conditions and only a few tolerant species survive to become adult trees. We propose that natural disturbances play an important role by altering limiting resources, allowing seeds of nonflooded forest species to germinate. This paper elucidates the turnover between plant life stages in swamp forests and suggests mechanisms that may shape these communities.
Species delimitation remains a challenge worldwide, but especially in biodiversity hotspots such as the Amazon. Here, we use an integrative taxonomic approach that combines data from morphology, ...phylogenomics, and leaf spectroscopy to clarify the species limits within the Protium heptaphyllum species complex, which includes subsp. cordatum, subsp. heptaphyllum, and subsp. ulei. Molecular phylogeny indicates that populations of subsp. cordatum do not belong to the P. heptaphyllum clade, while morphology and near‐infrared spectroscopy data provide additional support for the recognition of a separate taxon. Protium cordatum (Burseraceae) is reinstated at species rank and described in detail. As circumscribed here, P. cordatum is endemic to white‐sand savannas located in the Faro and Tucuruí Districts, Pará State, Brazil, whereas P. heptaphyllum is a dominant and widespread plant lineage found in Amazonia, the Cerrado, and the Brazilian Atlantic Forest. We present an identification key to P. cordatum and closely related lineages and a detailed taxonomic description of P. cordatum, including habitat and distribution, a list and images of diagnostic features. This study demonstrates the importance of using multiple tools to characterize and distinguish plant species in highly diverse tropical regions.
•Coarse woody debris (CWD) decomposition was measured in flooded and unflooded forests.•Exponential models explain relationship between decomposition rate and wood density.•Lower CWD decomposition ...rate was found in seasonally flooded forest.•Residence time estimated for CWD to disappear in both formations is just under 40years.
Estimates of carbon-stock changes in forest ecosystems require information on dead wood decomposition rates. In the Amazon, the lack of data is dramatic due to the small number of studies and the large range of forest types. The aim of this study was to estimate the decomposition rate of coarse woody debris (CWD) in two oligotrophic undisturbed forest formations of the northern Brazilian Amazon: seasonally flooded and unflooded. We analyzed 20 arboreal individuals (11 tree species and 3palm species) with distinct wood-density categories. The mean annual decomposition rate of all samples independent of forest formation ranged from 0.044 to 0.963yr−1, considering two observation periods (12 and 24months). The highest rate (0.732±0.206 SDyr−1) was observed for the lowest wood-density class of palms, whereas the lowest rate (0.119±0.101yr−1) was determined for trees with high wood density. In terms of forest formation, the rates values differ when weighted by the wood-density classes, indicating that unflooded forest (0.181±0.083 SE yr−1; mean decay time 11–30years) has a decomposition rate ∼19% higher than the seasonally flooded formations (0.152±0.072yr−1; 13–37years). This result reflects the dominance of species with high wood density in seasonally flooded formations. In both formations 95% of the dead wood is expected to disappear within 30–40years. Based on our results, we conclude that the CWD decomposition in the studied area is slower in forests on nutrient-poor seasonally flooded soils, where structure and species composition result in ∼40% of the aboveground biomass being in tree species with high wood density. Thus, it is estimated that CWD in seasonally flooded forest formations has longer residence time and slower carbon release by decomposition (respiration) than in unflooded forests. These results improve our ability to model stocks and fluxes of carbon derived from decomposition of dead wood in undisturbed oligotrophic forests in the Rio Negro-Rio Branco Basin, northern Brazilian Amazon.
Question: How much variation in plant community structure and composition can be predicted using soil, flooding and topography in white-sand vegetation of northern Amazonia? Location: Brazil, ...northern Amazon, Roraima State, Viruá National Park (01°46′ 34″ N, 61°02′06″ W). Methods: Data from 17, 1-ha permanent plots distributed across a 25 km² landscape within the Viruá National Park, northern Amazonia, was used to assess the soil, flooding and topography effects on tree species composition, diversity and structure. Our analyses were based on 16 599 trees (DBH ≥ 1 cm) belonging to 303 species. Principal components analysis (PCA) was used to reduce the dimensionality of soil variables, whereas dimensionality of floristic composition assemblage was reduced using non-metric multidimensional scaling (NMDS). Multiple regression analysis was used to test combined effects of soil, flooding and topography on floristic composition, diversity, basal area and tree density. Results: Depending on the diameter class or the type of data (qualitative or quantitative), NMDS axis 1 explained 45—84% of total variation in species composition among plots. The first and second axes from PCA explained, respectively, 54.8% and 15.1% of the variation related to soil gradients. Soil texture and fertility (PCA axis 1) were the most important predictors of the variation in tree composition, diversity and structure for the three different size classes analysed (DBH ≥ 1 cm, 1 cm ≤ DBH ≤ 9.9 cm and DBH ≥ 10 cm). Overall, plots on more fertile clayey soils showed higher tree diversity and basal area than those on well-drained sandy soils. Although flooding had little effect on the tree community, the water level was higher in high-stature forests established on more clayey and fertile soils. Conclusions: Even though soils in the study area are predominantly sandy and oligotrophic, our findings highlight the importance of soil in structuring plant communities of seasonally flooded white-sand vegetation at mesoscales in the Amazon Basin.
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