South American Rainforest Research Articles

The Agoutis: A Future Model for Ecologically Relevant Neuroscience and Physiology In Natura

ABSTRACTThe overarching goal of neurobiology is to understand how complex behaviors are generated by the nervous system. The behavior of each species, and the brain that controls it, is shaped by the historical and current state of the environment that they inhabit. This fact is juxtaposed with the reductionist approach of neuroscience that isolates animals from their natural environment. Understanding how brains evolved to orchestrate the myriads of natural behaviors an animal performs in response to its environment requires an integrative approach to neuroscience that considers ecology, ethology, and evolution. Current technological developments are leading us to an inflection point at which studying brain functions in the wild is now possible. Ecological studies on how the environment affects behavior of animals (i.e., hibernation, foraging, food hoarding, and nest building) have framed a plurality of questions to be answered mechanistically, and yet, only few studies have addressed the relationship between the environment and the brain's anatomy and physiology. Neuroscience needs new animal models that allow us to tackle such questions in the wild. Here, we propose a new animal model for wild neuroscience, the agouti (Dasyprocta spp.), a large wild rodent playing a critical seasonal role in the maintenance of the central and south American rainforest ecosystems. We focus on how a rodent model, like the agouti, will allow for the investigation of large‐scale brain dynamics during seasonal behaviors of ecological importance: scatter‐hoarding and retrieval. We describe agouti evolution, ecology, and physiology as well as neuro‐anatomical and neurophysiological studies, which have set the foundation for future neuroscience in natura. We suggest agoutis have the potential to be a groundbreaking model for wild neuroscience.

South American Rainforests Are on the Brink of Becoming Carbon Sources

Plants’ ability to stock carbon ceased during the 2015–2016 El Ni�o, as temperatures skyrocketed and trees died.

INSIGHTS INTO THE HABITS OF THE ELUSIVE NOCTURNAL CURASSOW (NOTHOCRAX URUMUTUM)

Nocturnal curassows (Nothocrax urumutum) are one of the most enigmatic birds from South American rainforests. Their elusive habits and their nocturnal vocal behavior have led to the generalized assumption that they differ from other curassows in their presumable nocturnal habits. Here, we compiled camera trap data from long term projects in the Amazon rainforest and the Andes Cordillera piedmont to describe the temporal activity of Nocturnal Curassows. Based on an overall sampling effort of 68838 camera nights we obtained 274 independent records of their activity. The results of this study evidence that Nothocrax has diurnal habits and resembles in activity patterns to all other cracids more than previously expected. This study highlights the use of novel technologies and collaborative research towards the understanding of the natural history, ecology and behavior of animals with cryptic behaviors such as the Nocturnal Curassows.

Taxonomic Revision ofSpiranthera(Rutaceae)

Abstract—Spiranthera(Rutaceae, Galipeeae) is a neotropical genus, recognizable mainly by the presence of trifoliate leaves, pentamerous flowers, exappendiculate filaments, spirally revolute anthers lacking a basal appendage, a campanulate disk, and anelongated gynophore. Species in this genus are mostly sciophilous treelets from South American rainforests, except forSpiranthera odoratissima, the most widespread species, which is a shrub inhabiting savannic formations and showing the widest morphological variation within the genus. In this taxonomic revision we present an extensive morphological analysis of the genus based on data from field work and from herbaria, an identification key, and descriptions and illustrations of the six species here recognized, including a new one from Iquitos, Peru. Also, we present updated information on the geographic distribution of the species, their habitats, and their morphological variability.

A deep decarbonization pathway for Peru's rainforest

Peru holds an important portion of the South American rainforest. An average deforestation rate of 145,000 ha a year makes it the largest source of GHG emissions. Based on the drivers of deforestation, this paper proposes a deep decarbonization pathway (DDP) through the year 2050 with the purpose of taking the country closer to achieving the net-zero emissions goal. The impacts of the pathway are estimated using POLYSYS-Peru, an equilibrium displacement model for the integrated analysis of land-use changes and agriculture. The results indicate that the proposed DDP pathway, by preventing the deforestation of 4 million hectares of primary forests, would reduce GHG emissions by an accumulated 1778 Mt CO2 eq. compared to the business as usual scenario, and 497 Mt CO2 eq. more than the Nationally Determined Contributions.

The use of ipecacuanha (Carapichea ipecacuanha) in veterinary and human medicine

The aim of review is to show the benefits of plant species Carapichea ipecacuanha, its unique emetic properties and various compounds. C. ipecacuanha is a plant native to South and Central American rainforests. Its root contains two powerful alkaloids, emetine and cephaeline, which have emetic and expectorant properties. These roots are used to make ipecac syrup, which is used in both human and veterinary medicine. The most important use of ipecac syrup is vomiting induction, after the toxic compounds ingestion or after a drug overdose. In low doses, it serves as an expectorant to thin mucus and relieve coughing. Chemical compounds, such as emetine and cephaeline extracted from the plant have multiple functions in treating various ailments. Thus, it is important to get familiar with this plant species from a medicinal perspective.

Cyanogenic, carotenoids and protein composition in leaves and roots across seven diverse population found in the world cassava germplasm collection at CIAT, Colombia

SummaryThe objective of this study was to characterise the nutritional potential of leaves and identify a diversity centre with low cyanide and high nutrient content among 178 Latin American cassava genotypes. This field‐based collection represents the seven diversity centres, held at The International Center for Tropical Agriculture (CIAT Palmira, Colombia) by the Cassava Program. The cyanide, all‐trans‐β‐carotene and lutein concentrations in cassava leaves ranged from 346 to 7484 ppm dry basis (db), from 174–547 μg g−1db and 15–181 μg g−1db, respectively. Cassava leaves also showed significant levels of essential amino acids leucine, lysine, phenylalanine, valine and threonine, and average total protein content of 26.24 g 100 g−1db. Among seven diversity centres, South American rainforest group showed low cyanide and high carotene content in leaves. In addition, VEN77 and PAN51 genotypes stood out for having low cyanide in leaves and roots and high carotene in leaves. This genetic diversity can be used to select high potential progenitors for breeding purposes.

Caranan Fiber from Mauritiella armata Palm Tree as Novel Reinforcement for Epoxy Composites.

A growing environmental concern is increasing the search for new sustainable materials. In this scenario, natural lignocellulosic fibers (NLFs) became an important alternative to replace synthetic fibers commonly used as composites reinforcement. In this regard, unknown NLFs such as the caranan fiber (Mauritiella armata) found in South American rain forests revealed promising properties for engineering applications. Thus, for the first time, the present work conducted a technical characterization of caranan fiber-incorporated composites. Epoxy matrix composites with 10, 20 and 30 vol% of continuous and aligned caranan fibers were investigated by tensile tests, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Composites with more than 10% vol of caranan fibers significantly increase the elastic modulus and toughness in comparison to the neat epoxy. Indeed, the composite with 30 vol% was 50% stiffer, 130% tougher, and 100% stronger, which characterized an effective reinforcement. As for the elastic modulus, total strain and tensile toughness, there is a clear tendency of improvement with the amount of caranan fiber. The TGA disclosed the highest onset temperature of degradation (298 °C) with the least mass loss (36.8%) for the 30 vol% caranan fiber composite. It also displayed a higher degradation peak at 334 °C among the studied composites. The lowest glass transition temperature of 63 °C was obtained by DSC, while the highest of 113 °C by dynamic mechanical analysis (DMA) for the 30 vol% caranan composite. These basic technical findings emphasize the caranan fiber potential as reinforcement for polymer composites.

Molecular phylogenetic inference of the howler monkey radiation (Primates: Alouatta).

Howler monkeys (Alouatta), comprising between nine and 14 species and ranging from southern Mexico to northern Argentina, are the most widely distributed platyrrhines. Previous phylogenetic studies of howlers have used chromosomal and morphological characters and a limited number of molecular markers; however, branching patterns conflict between studies or remain unresolved. We performed a new phylogenetic analysis of Alouatta using both concatenated and coalescent-based species tree approaches based on 14 unlinked non-coding intergenic nuclear regions. Our taxon sampling included five of the seven South American species (Alouatta caraya, Alouatta belzebul, Alouatta guariba, Alouatta seniculus, Alouatta sara) and the two recognized species from Mesoamerica (Alouatta pigra, Alouatta palliata). Similarly to previous studies, our phylogenies supported a Mesoamerican cladeand a South American clade. For the South American howlers, both methods recovered the Atlantic Forest endemic A. guariba as sister to all remaining South American species, albeit with moderate support. Moreover, we found no support for the previously proposed sister relationship between A. guariba and A. belzebul. For the first time, a clade composed of A. sara and A. caraya was identified. The relationships among the other South American howlers, however, were not fully supported. Our estimates for divergence times within Alouatta are generally older compared to estimates in earlier studies. However, they conform to recent studies proposing a Miocene age for the Isthmus of Panama and for the uplift of the northern Andes. Our results also point to an early genetic isolation of A. guariba in the Atlantic Forest, in agreement with the hypothesis of biotic exchange across South American rain forests in the Miocene. Collectively, these findings contribute to a better understanding of the diversification processes among howler monkey species; however, they also suggest that further comprehension of the evolutionary history of the Alouatta radiation will rely on broadened taxonomic, geographic, and genomic sampling.

The combined role of dispersal and niche evolution in the diversification of Neotropical lizards.

Ecological requirements and environmental conditions can influence diversification across temporal and spatial scales. Understanding the role of ecological niche evolution under phylogenetic contexts provides insights on speciation mechanisms and possible responses to future climatic change. Large‐scale phyloclimatic studies on the megadiverse Neotropics, where biomes with contrasting vegetation types occur in narrow contact, are rare. We integrate ecological and biogeographic data with phylogenetic comparative methods, to investigate the relative roles of biogeographic events and niche divergence and conservatism on the diversification of the lizard genus Kentropyx Spix, 1825 (Squamata: Teiidae), distributed in South American rainforests and savannas. Using five molecular markers, we estimated a dated species tree, which recovered three clades coincident with previously proposed species groups diverging during the mid‐Miocene. Biogeography reconstruction indicates a role of successive dispersal events from an ancestral range in the Brazilian Shield and western Amazonia. Ancestral reconstruction of climatic tolerances and niche overlap metrics indicates a trend of conservatism during the diversification of groups from the Amazon Basin and Guiana Shield, and a strong signal of niche divergence in the Brazilian Shield savannas. Our results suggest that climatic‐driven divergence at dynamic forest‐savanna borders might have resulted in adaptation to new environmental niches, promoting habitat shifts and shaping speciation patterns of Neotropical lizards. Dispersal and ecological divergence could have a more important role in Neotropical diversification than previously thought.

The land snail fauna of a South American rainforest biodiversity hotspot: the Panguana conservation area in the Peruvian Amazon

Abstract We investigated the land snail fauna of the Panguana conservation area on the western rim of the Amazonas basin in Peru. A total of 2,322 individuals assigned to 65 land snail species were collected in 32 plots. Ten additional species were found in collections made on previous expeditions to Panguana. On the basis of available data, Panguana is the most species rich locality for land snails in South America. The species density of 75 land snail species in c. 2 km2 of rather homogeneous rainforest is also high on a global scale. The land snail fauna of Panguana is characterized by a very high proportion of species belonging to the carnivorous family Scolodontidae, many of which are likely to be new to science. The fauna includes seven species that are new records for Peru, and the species Hirtudiscus sp., Xenodiscula venezuelensis, Geostilbia aperta, Guppya gundlachii and Thysanophora plagioptycha represent genera not previously recorded from the country. The synanthropic species Allopeas gracile, Opeas hannense, Subulina octona, Geostilbia aperta and Gastrocopta servilis form an ecologically distinct group that occurs mainly in sites strongly modified by humans. The presence of these species on the margin of the Amazon rainforest is evidence of the ongoing homogenization of the global fauna.

World’s oldest chocolate was made 5300 years ago—in a South American rainforest

World’s oldest chocolate was made 5300 years ago—in a South American rainforest

Hanging out for a drink

A long-held presumption in ecology is that sloths get all the water they need from the foliage they consume, and few documented observations exist of either of the two sloth genera drinking in the wild. We photographed a male brown-throated sloth (Bradypus variegatus) lapping water from the surface of a river in Costa Rica. This sighting prompts many additional questions. For example, how widespread is drinking behavior and how frequently does it occur? Methods used to assess water retention in wild sloths suggest that this behavior seldom occurs, so drinking is likely a method of maintaining osmotic balance when faced with extreme ambient temperatures, low precipitation, or increased consumption of mature (ie drier) leaves. If fresh water access is indeed important, there are further implications relating to the captive husbandry of sloths in zoos and rescue centers (where they often face drier climes, typically don't have access to water, and have a very low survival rate), and for conservation, especially after habitat fragmentation, where changes in land use can restrict water access (eg irrigation diverting stable water sources, roads that are difficult for strictly arboreal animals to cross). Moving forward, the predicted trend toward a hotter, drier climate for Central and South American rainforests may negatively impact the sloths’ potentially delicate water balance, particularly in view of their limited energy budget and inability to travel long distances. If all sloths need a drink from time to time to stay healthy, it's important to make sure they can get one. G Nichol

Phylogeny and biogeography of Phyllomys (Rodentia: Echimyidae) reveal a new species from the Cerrado and suggest Miocene connections of the Amazon and Atlantic Forest

Phyllomys is the most species-rich genus among spiny tree rats of the family Echimyidae and includes members widely distributed throughout the Atlantic Forest of South America. Among recognized species recovered in previous studies, 4 lineages are unnamed and their taxonomic distinctness needs further investigation. Biogeographic analyses recovered an Amazonian ancestor of the basal lineage leading to living Phyllomys, suggesting ancient connections between the 2 largest South American rainforests, and presence of rainforest corridors within the central Brazilian dry biomes. Based on exhaustive taxonomic sampling of Phyllomys, applying multigene phylogenetic methods, and morphological and karyological data, we described a new species of Phyllomys from central Brazil. Geographical records from the center of the Cerrado biome of central Brazil indicate an unexpected location for the distribution of the genus, given the contrast between the physical and biological characteristics of the Cerrado and Atlantic Forest habitats. Contrary to previous studies, the analysis of the ancestral geographic range performed here suggests a Cerrado ancestral distribution for Phyllomys during the late Miocene. This result favors the hypothesis of a past link between the Amazon and Atlantic Forest in central Brazil, through the region occupied today by the dry Cerrado, and that forest expansions and contractions may have occurred in Brazilian dry biomes over the course of the Tertiary.

Dry habitats were crucibles of domestication in the evolution of agriculture in ants.

The evolution of ant agriculture, as practised by the fungus-farming ‘attine’ ants, is thought to have arisen in the wet rainforests of South America about 55–65 Ma. Most subsequent attine agricultural evolution, including the domestication event that produced the ancestor of higher attine cultivars, is likewise hypothesized to have occurred in South American rainforests. The ‘out-of-the-rainforest’ hypothesis, while generally accepted, has never been tested in a phylogenetic context. It also presents a problem for explaining how fungal domestication might have occurred, given that isolation from free-living populations is required. Here, we use phylogenomic data from ultra-conserved element (UCE) loci to reconstruct the evolutionary history of fungus-farming ants, reduce topological uncertainty, and identify the closest non-fungus-growing ant relative. Using the phylogeny we infer the history of attine agricultural systems, habitat preference and biogeography. Our results show that the out-of-the-rainforest hypothesis is correct with regard to the origin of attine ant agriculture; however, contrary to expectation, we find that the transition from lower to higher agriculture is very likely to have occurred in a seasonally dry habitat, inhospitable to the growth of free-living populations of attine fungal cultivars. We suggest that dry habitats favoured the isolation of attine cultivars over the evolutionary time spans necessary for domestication to occur.

Reaching the canopy on the ground: incidence of infection and host-use by mistletoes (Loranthaceae and Viscaceae) on trees felled for timber in Amazonian rainforests

There is a profound absence of knowledge of infestation prevalence and host-use by mistletoes of mature South American tropical rainforests. In this study, we fill this gap using information gathered from felled trees at a logging concession area in Amazonian Brazil. We sampled individuals of 18 tree species, which occurred in two forest physiognomies; open forest with canopy interrupted by palm trees and closed, denser forest, with emergent trees. We hypothesized that infection incidence would be higher in open than in closed forest, irrespective of the mistletoe species involved. In addition, we expected that mistletoe parasitism would be higher on host species that were more abundant, taller, deciduous, and had less dense wood. We sampled 870 individual trees in both sites combined. All but one host species was infected by at least one species of mistletoe. We found 13 mistletoe species/morphospecies, Loranthaceae (7) and Viscaceae (6), parasitizing very different hosts. Mistletoe infection incidence was higher in the closed forest (10.3%) than in the open forest (5.4%). In the closed forest, host height influenced incidence positively, while deciduousness had a negative influence. Our results show that mistletoes are common in the canopy of pristine tropical forests and, contrary to expectations, that infection incidence was higher in the closed forest. The positive relation between infection incidence and host height in this forest type suggests that emergent trees have higher chances of being infected than individuals of correspondent species in the lower forest layers.

Genotoxicity and cytotoxicity of oxindole alkaloids from Uncaria tomentosa (cat's claw): Chemotype relevance

Ethnopharmacological relevanceUncaria tomentosa (Willdenow ex Roemer & Schultes) DC. (Rubiaceae) or cat's claw is a climber vine from the South American rainforest used in folk medicine for cancer treatment. Its antitumor activity has been mostly ascribed to pentacyclic oxindole alkaloids (POA) from stem bark and leaves while the activity of tetracyclic oxindole alkaloids (TOA) remains unknown. In recent times, the occurrence of three chemotypes based on its oxindole alkaloid profile was noticed in U. tomentosa, namely, chemotype I (POA cis D/E ring junction); chemotype II (POA trans D/E ring junction) or chemotype III (TOA). Consequently, the relationship between the chemotype and cytotoxic and genotoxic activities deserves attention. Aim of the studyTo evaluate the influence of cat's claw chemotypes on genotoxicity and cytotoxicity against non malignant and malignant human cell line models. Material and methodsFour authentic stem bark cat's claw samples (SI-SIV) and two leaf samples (LII and LIII) were analyzed by HPLC-PDA, properly extracted and fractioned by ion-exchange to obtain oxindole alkaloid purified fractions (OAPFs). The freeze-dried fractions were assayed for genotoxicity and cytotoxicity against human leukocytes (non malignant cell line) by the micronuclei frequency method and the alkaline comet DNA assay, and the trypan blue method, respectively. Moreover, the cytotoxicity of each OAPF was evaluated against a human bladder cancer cell line (T24) and human glioblastoma cell line (U-251-MG) by MTT method (malignant cell lines). Additionally, the isomerization of oxindole alkaloids throughout the course of cell incubation was monitored by HPLC-PDA. ResultsBased on HPLC-PDA analyses, sample SI was characterized as chemotype I, while samples SII and LII were characterized as chemotype II, and samples SIII, SIV and LIII as chemotype III. The chemotypes showed comparable cytotoxic activity toward malignant cell lines (T24 and U-251-MG) unlike human leukocytes (non malignant cell line), where this activity was clearly distinct. Chemotype II (POA trans D/E ring junction) showed a higher selectivity index (SI) against malignant cells (SI=1.11–3.04) than chemotype I (SI=0.10−0.19) and III (SI=0.21–0.57). No important genotoxic potential was found by micronuclei frequency and alkaline comet DNA assays. Despite the isomerization of oxindole alkaloids during the cell incubation, the chemotype of the cat's claw samples remained unchanged. ConclusionCat's claw chemotypes showed different selectivity against human malignant cells, so that the correct identification of each chemotype seems to be important to better understand its antitumor potential.

Effect of ethyl acetate fraction of urucum extract on cell viability of peripheral blood mononuclear cells and antimicrobial activity in human pathogenic bacteria.

Effect of ethyl acetate fraction of urucum extract on cell viability of peripheral blood mononuclear cells and antimicrobial activity in human pathogenic bacteria.

CHEMICAL COMPOSITION VARIABILITY IN THEUncaria tomentosa(cat's claw) WILD POPULATION

Uncaria tomentosa (cat's claw) is a vine widely distributed throughout the South-American rainforest. Many studies investigating the chemical composition of cat's claw have focused on the pentacyclic (POA) and tetracyclic oxindole alkaloids (TOA), quinovic acid glycosides (QAG), and polyphenols (PPH). Nevertheless, it is still uncertain how environmental factors affect chemical groups. The aim of this work was to better understand the influence of environmental factors (geographic origin, altitude, and season) on cat's claw chemical composition. Stem bark, branches and leaf samples were extracted and analyzed by HPLC-PDA. The data obtained were explored by multivariate analysis (HCA and PCA). Higher amounts of oxindole alkaloids and PPH were found in leaves, followed by stem bark and branches. No clear relationship was verified among geographic origin or altitude and chemical composition, which remained unchanged regardless of season (dry or rainy). However, three oxindole alkaloid chemotypes were clearly recognized: chemotype I (POA with cis D/E ring junction); chemotype II (POA with trans D/E ring junction); and chemotype III (TOA). Thus, environmental factors appear to have only a minor influence on the chemical heterogeneity of the cat's claw wild population. Nevertheless, the occurrence of different chemotypes based on alkaloid profiles seems to be clear.

Influence of 1100 years of burning on the central African rainforest

Four major forest types are currently present in the central African rainforest; mixed forest, Marantaceae forest, monodominant Gilbertiodendron forest and swamp forest. These forest types span vast areas and demonstrate highly significant differences in diversity and productivity; yet factors responsible for their formation are poorly understood. One hypothesis is that they are as a consequence of different intensities of past human activity, in particular burning. Here we present results from fossil charcoal contained in 12 sediment cores spanning the last 2500 yr and covering a spatial area of more than 900 km2. These records demonstrate that burning started in the last 1100 yr with areas currently covered by Marantaceae forest undergoing more frequent burning events than the other forest types. In comparison monodominant Gilbertiodendron forest appear to have undergone large burning events only in the past 200 yr. These records also demonstrate a lack of spatial relationship between fire events at the different sites (discontinuous and asynchronous) suggesting that these fires resulted from localised burning events probably caused by human ignitions. Whilst the large spatial scale of past human activities in the South American rainforest is now widely acknowledged, these results indicate, for the first time, the significant impact that early human populations had on the community composition of central African rainforest.