Influence of habitat on the reproductive ecology of the Amazonian palm, Mauritia flexuosa, in Roraima, Brazil

Although Mauritia flexuosa (Arecaceae) plays a pivotal role in the ecology and economy of the Amazon, and occurs in a variety of habitats, little is known about the influence of habitat on the reproductive biology of this palm. My dissertation focuses on the reproductive biology of M. flexuosa in three habitats in Roraima, Brazil: undisturbed forest, undisturbed forest-savanna ecotone, and savanna disturbed by plantations of the exotic tree, Acacia mangium. First, I calculated sex ratios and linked precipitation patterns with phenology. Sex ratios were female-biased. Precipitation was negatively associated with flowering, and positively associated with fruiting. Habitat appears to have no significant influence on phenology of M. flexuosa, although short-term climate variation may affect phenology of this species. Second, I examined floral biology, observed floral visitors, and performed exclusion experiments to determine the pollination system of M. flexuosa. Fruit set did not differ significantly between the visitor exclusion treatment and the control, but was significantly lowest in the wind + visitor exclusion treatment, suggesting that this dioecious palm is anemophilous, independent of habitat. Third, I identified the abiotic and biotic factors explaining variation in fruit mass, seed mass, seed number per fruit, and total fruit yield among habitats. Soil moisture and flooding during the wet season were the best predictors of fruit and seed output. The number of leaves, diameter at breast height, and height were all accurate predictors of reproductive output, but crown volume did not accurately predict fruit yields. Results re-evaluate traditional assumptions about wind-pollination in the tropics, and highlight abiotic and biotic factors responsible for variation in reproductive output of M. flexuosa, with implications for effective management of this palm. Finally, I interviewed harvesters and vendors to document the traditional knowledge and market dynamics of the fruit of M. flexuosa, buriti. Traditional knowledge corroborated results from scientific studies. Vendors argued that the price of buriti must increase, and must fluctuate with varying supply. With appropriate economic incentives to vendors/harvesters, Roraima may expand its market infrastructure for buriti, effectively stimulating the regional economy and practicing sustainable harvesting.

Influence of Habitat on the Reproductive Ecology of the Amazonian Palm, Mauritia flexuosa, in Roraima, Brazil

Although Mauritia flexuosa (Arecaceae) plays a pivotal role in the ecology and economy of the Amazon, and occurs in a variety of habitats, little is known about the influence of habitat on the reproductive biology of this palm. My dissertation focuses on the reproductive biology of M. flexuosa in three habitats in Roraima, Brazil: undisturbed forest, undisturbed forest-savanna ecotone, and savanna disturbed by plantations of the exotic tree, Acacia mangium. First, I calculated sex ratios and linked precipitation patterns with phenology. Sex ratios were female-biased. Precipitation was negatively associated with flowering, and positively associated with fruiting. Habitat appears to have no significant influence on phenology of M. flexuosa, although short-term climate variation may affect phenology of this species. Second, I examined floral biology, observed floral visitors, and performed exclusion experiments to determine the pollination system of M. flexuosa. Fruit set did not differ significantly between the visitor exclusion treatment and the control, but was significantly lowest in the wind + visitor exclusion treatment, suggesting that this dioecious palm is anemophilous, independent of habitat. Third, I identified the abiotic and biotic factors explaining variation in fruit mass, seed mass, seed number per fruit, and total fruit yield among habitats. Soil moisture and flooding during the wet season were the best predictors of fruit and seed output. The number of leaves, diameter at breast height, and height were all accurate predictors of reproductive output, but crown volume did not accurately predict fruit yields. Results re-evaluate traditional assumptions about wind-pollination in the tropics, and highlight abiotic and biotic factors responsible for variation in reproductive output of M. flexuosa, with implications for effective management of this palm. Finally, I interviewed harvesters and vendors to document the traditional knowledge and market dynamics of the fruit of M. flexuosa, buriti. Traditional knowledge corroborated results from scientific studies. Vendors argued that the price of buriti must increase, and must fluctuate with varying supply. With appropriate economic incentives to vendors/harvesters, Roraima may expand its market infrastructure for buriti, effectively stimulating the regional economy and practicing sustainable harvesting.

Evaluation of the genotoxic and antigenotoxic effects after acute and subacute treatments with acai pulp (Euterpe oleracea Mart.) on mice using the erythrocytes micronucleus test and the comet assay

Acai, the fruit of a palm native to the Amazonian basin, is widely distributed in northern South America, where it has considerable economic importance. Whereas individual polyphenolics compounds in Acai have been extensively evaluated, studies of the intact fruit and its biological properties are lacking. Therefore, the present study was undertaken to investigate the in vivo genotoxicity of Acai and its possible antigenotoxicity on doxorubicin (DXR)-induced DNA damage. The Acai pulp doses selected were 3.33, 10.0 and 16.67 g/kg b.w. administered by gavage alone or prior to DXR (16 mg/kg b.w.) administered by intraperitoneal injection. Swiss albino mice were distributed in eight groups for acute treatment with acai pulp (24 h) and eight groups for subacute treatment (daily for 14 consecutive days) before euthanasia. The negative control groups were treated in a similar way. The results of chemical analysis suggested the presence of carotenoids, anthocyanins, phenolic. and flavonoids in Acai pulp. The endpoints analyzed were micronucleus induction in bone marrow and peripheral blood cells polychromatic erythrocytes, and DNA damage in peripheral blood, liver and kidney cells assessed using the alkaline (pH > 13) comet assay. There were no statistically significant differences (p > 0.05) between the negative control and the groups treated with the three doses of Acai pulp alone in all endpoints analyzed, demonstrating the absence of genotoxic effects. The protective effects of Acai pulp were observed in both acute and subacute treatments, when administered prior to DXR. In general, subacute treatment provided greater efficiency in protecting against DXR-induced DNA damage in liver and kidney cells. These protective effects can be explained as the result of the phytochemicals present in Acai pulp. These results will be applied to the developmental of food with functional characteristics, as well as to explore the characteristics of Acai as a health promoter. (C) 2009 Elsevier B.V. All rights reserved.

Antioxidant and cytotoxic activities of 'açaí' (Euterpe precatoria Mart.)

Decoction of roots of the Amazonian palm açaí (Euterpe precatoria Mart.) is widely used by Brazilian and Peruvian people as an anti-inflammatory, to heal kidney and liver diseases and against snake bites. In this study, the antioxidant activity of extracts and flavonoids (quercetin, catechin, epicatechin, rutin and astilbin) isolated from roots and leaf stalks of E. precatoria was investigated using β-carotene in TLC plates and DPPH radical scavenging in a spectrophotometric bioassay. All extracts and flavonoids showed activity. Also, the cytotoxic activity of these extracts was evaluated by the brine shrimp (Artemia salina) larvicide bioassay and was lower than that of lapachol, used as control. The presence of flavonoids and sitosterol-3-O-β-D-glucopyranoside in the extracts can justify the use of the plant in traditional medicine.

Avaliação dos parâmetros físico-químicos e estabilidade de compostos bioativos em óleos de polpa e amêndoa de frutos amazônicos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Molecular phylogenetics of the palm tribe Geonomeae, and differentiation of Geonoma macrostachys western Amazonian varieties

Phylogenetic analyses were performed on six genera and 46 species of the Neotropical palm tribe Geonomeae. The analyses were based on two low copy nuclear DNA sequences from the genes encoding phosphoribulokinase and RNA polymerase II. The basal node of the tribe was polytomous. Pholidostachys formed a monophyletic group. The currently accepted genera Calyptronoma and Calyptrogyne formed a well-supported clade with Calyptronoma resolved as paraphyletic to Calyptrogyne. Geonoma formed a strongly supported monophyletic group consisting of two main clades. ^ An evaluation of the genetic distinctness between Geonoma macrostachys varieties at a local and regional scale using inter-simple sequence repeat (ISSR) markers was performed. Clustering, ordination, and AMOVA suggested a lack of genetic distinctness between varieties at the regional level. A hierarchical AMOVA revealed that the genetic diversity mainly lies among the four localities sampled. A significant genetic differentiation between sympatric varieties occurred in one locality only. The current taxonomy of G. macrostachys, which recognizes only one species, was therefore supported. ^ The preferred habitat of sympatric G. macrostachys varieties with respect to edaphic, topographic, and light factors in three Peruvian lowland forests was studied. The two varieties were mostly encountered in different physiographically defined habitats, with variety acaulis occurring more often in floodplain forest and variety macrostachys in the tierra firme. Comparison of means tests revealed that nine to eleven of the 16 environmental variables were significantly different between varieties. Edaphic factors, mainly soil texture and K content, were better contributors than light conditions to distinguish the habitats occupied by the two varieties in all three study sites. It is concluded that habitat differentiation plays a role in the coexistence of these closely related species taxa. ^

Exploration of the acarine fauna on coconut palm in Brazil with emphasis on Aceria guerreronis (Acari : Eriophyidae) and its natural enemies

Coconut is an important crop in tropical and subtropical regions. Among the mites that infest coconut palms, Aceria guerreronis Keifer is economically the most important. We conducted surveys throughout the coconut growing areas of Brazil. Samples were taken from attached coconuts, leaflets, fallen coconuts and inflorescences of coconut palms in 112 localities aiming to determine the Occurrence and the distribution of phytophagous mites, particularly A. guerreronis, and associated natural enemies. Aceria guerreronis was the most abundant phytophagous mite followed by Steneotarsonemus concavuscutum Lofego & Gondim Jr. and Steneotarsonemus furcatus De Leon (Tarsonemidae). Infestation by A. guerreronis was recorded in 87% of the visited localities. About 81% of all predatory mites belonged to the family Phytoseiidae, mainly represented by Neoseiulus paspalivorus De Leon, Neoseiulus baraki Athias-Henriot and Amblyseius largoensis Muma; 12% were Ascidae, mainly Proctolaelaps bickleyi Bram, Proctolaelaps sp nov and Lasioseius subterraneus Chant. Neoseiulus paspalivorus and N. baraki were the most abundant predators on attached coconuts. Ascidae were predominant on fallen coconuts, while A. largoensis was predominant on leaflets; no mites were found on branches of inflorescences. Leaflets harboured higher mite diversity than the attached coconuts. Mite diversity was the highest in the state Para and on palms surrounded by seasonal forests and Amazonian rain-forests. Neoseiulus paspalivorus, N. baraki and P. bickleyi were identified as the most promising predators of A. guerreronis. Analyses of the influence of climatic factors revealed that dry ambient conditions favour the establishment of A. guerreronis. Neoseiulus paspalivorus and N. baraki have differing climatic requirements; the former being more abundant in warm and dry areas, the latter prevailing ill moderately tempered and humid areas. We discuss the significance of our findings for natural and biological control of A. guerreronis.

Diversity of the land resources in the Amazonian State of Rondônia, Brazil

Conflicting opinions are recorded in the literature concerning the suitability of Amazon lands for sustainable agriculture following deforestation. This article has been written to shed light on this question by summarizing climate, landform, soil and vegetation features from the findings of a land resource study of the Brazilian state of Rondônia in south-west Amazonia. The work, which followed the World Soils and Terrain Digital Database (SOTER) methodology, was financed by the World Bank. During the course of the survey special emphasis was given to studying soils; 2914 profiles were analyzed and recorded. The study identified a complex pattern of land units with clear differences in climate, landform, soils and native vegetation. Forested areas mosaic with lesser areas of natural savannas. The latter occur on both poorly-drained and well-drained, albeit nutrient deficient sandy soils. The tallest and most vigorous forests or their remnants were seen growing on well-drained soils formed from nutrient-rich parent materials. Many of these soils could, or are being used for productive agriculture. Soils developed on nutrient-poor parent materials support forests that are significantly lower in height, and would require large lime and fertilizer inputs for agriculture. Low forests with high palm populations and minor areas of wet land savannas cover the poorly drained soils. It is evident that forest clearing in the past was indiscriminant; this cannot be condoned. The diversity of land conditions found throughout Rondônia would suggest that many past studies in the Amazon have simply been too broad to identify significant soil differences.

Similar understorey structure in spite of edaphic and floristic dissimilarity in Amazonian forests

Forest structure determines light availability for understorey plants. The structure of lowland Amazonian forests is known to vary over long edaphic gradients, but whether more subtle edaphic variation also affects forest structure has not beenresolved. In western Amazonia, the majority of non-flooded forests grow on soils derived either from relatively fertile sediments of the Pebas Formation or from poorer sediments of the Nauta Formation. The objective of this study was to compare structure and light availability in the understorey of forests growing on these two geological formations. We measured canopy openness and tree stem densities in three size classes in northeastern Peru in a total of 275 study points in old-growth terra firme forests representing the two geological formations. We also documented variation in floristic composition (ferns, lycophytes and the palm Iriartea deltoidea) and used Landsat TM satellite image information to model the forest structural and floristic features over a larger area. The floristic compositions of forests on the two formations were clearly different, and this could also be modelled with the satellite imagery. In contrast, the field observations of forest structure gave only a weak indication that forests on the Nauta Formation might be denser than those on the Pebas Formation. The modelling of forest structural features with satellite imagery did not support this result. Our results indicate that the structure of forest understorey varies much less than floristic composition does over the studied edaphic difference.

Hydrolytic activity of bacterial lipases in amazonian vegetable oils

The data presented describe the development of an enzymatic process in vegetable oils. Six bacterial lipases were tested for their ability to hydrolyze. For each lipase assay, the p-NPP method was applied to obtain maximum enzymatic activities. The lipase from Burkholderia cepacia (lipase B-10) was the most effective in buriti oil, releasing 4840 µmol p-NP mL-1. The lipase from Klebsiella variicola (lipase B-22) was superior in passion fruit oil, releasing 4140 µmol p-NP mL-1 and also in babassu palm oil, releasing 2934 µmol p-NP mL-1. Research into the bioprocessing of oils aims to provide added value for this regional raw material.

Differentiation of neotropical ecosystems by modern soil phytolith assemblages and its implications for palaeoenvironmental and archaeological reconstructions II: Southwestern Amazonian forests

Accurate archaeological and palaeoenvironmental reconstructions using phytoliths relies on the study of modern reference material. In eastern Acre, Brazil, we examined whether the five most common forest types present today were able to be differentiated by their soil phytolith assemblages, and thus provide analogues with which to compare palaeoecological assemblages from pre-Columbian earthwork sites in the region. Surface soils and vegetation from dense humid evergreen forest, dense humid evergreen forest with high palm abundance, palm forest, bamboo forest and fluvial forest were sampled and their phytoliths analysed. Relative phytolith frequencies were statistically compared using Principal Components Analyses (PCAs). We found the major differences in species composition to be well-represented by the phytolith assemblages as all forest types, apart from the two sub-types of dense humid evergreen forest, could be differentiated. Larger phytoliths from the sand fraction were found to be more ecologically diagnostic than those from the silt fraction. The surface soil phytolith assemblages we analysed can therefore be used as analogues to improve the accuracy of archaeological and palaeoecological reconstructions in the region.

Distribution of extrafloral nectaries in different vegetation types of Amazonian Brazil

Surveys were carried out in terra firme' forest, successional forest, buritirana' (palm vegetation) and shrub canga' (savanna). Extrafloral nectaries (EFNs) were present in 30 plant species belonging to 22 genera and 14 families. Nectary species represented 17.6-53.3% of the species samples in different areas, with local abundances varying from 19.1-50.0%. The percentage of species with EFNs was greater in the flora of the shrub canga than in the terra firme and successional forests. Nectary plants were more abundant in the shrub canga and successional forest. The high abundance of EFNs may be the result of intense foraging activity by ants on plants, leading to the formation of facultative mutualism. -from Authors

Disproportionate single-species contribution to canopy-soil nutrient flux in an Amazonian rainforest

Rainfall, throughfall and stemflow were monitored on an event basis in an undisturbed open tropical rainforest with a large number of palm trees located in the southwestern Amazon basin of Brazil. Stemflow samples were collected from 24 trees with a diameter at breast height (DBH) > 5 cm, as well as eight young and four full-grown babassu palms (Attalea speciosa Mart.) for 5 weeks during the peak of the wet season. We calculated rainfall, throughfall and stemflow concentrations and fluxes of Na+, K+, Ca2+, Mg2+,, Cl-, SO42-, NO3- and H+ and stemflow volume-weighted mean concentrations and fluxes for three size classes of broadleaf trees and three size classes of palms. The concentrations of most solutes were higher in stemflow than in rainfall and increased with increasing tree and palm size. Concentration enrichments from rainfall to stemflow and throughfall were particularly high (81-fold) for NO3-. Stemflow fluxes of NO3- and H+ exceeded throughfall fluxes but stemflow fluxes of other solutes were less than throughfall fluxes. Stemflow solute fluxes to the forest soil were dominated by fluxes on babassu palms, which represented only 4% of total stem number and 10% of total basal area. For NO3-, stemflow contributed 51% of the total mass of nitrogen delivered to the forest floor (stemflow + throughfall) and represented more than a 2000-fold increase in NO3- flux compared what would have been delivered by rainfall alone on the equivalent area. Because these highly localized fluxes of both water and NO3- persist in time and space, they have the potential to affect patterns of soil moisture, microbial populations and other features of soil biogeochemistry conducive to the creation of hotspots for nitrogen leaching and denitrification, which could amount to an important fraction of total ecosystem fluxes. Because these hotspots occur over very small areas, they have likely gone undetected in previous studies and need to be considered as an important feature of the biogeochemistry of palm-rich tropical forest. (C) 2011 Elsevier B.V. All rights reserved.

Can the red palm mite threaten the Amazon vegetation?

The red palm mite Raoiella indica Hirst (Tenuipalpidae) was first reported in the New World in 2004, dispersing quickly and widely while adopting new plant species as hosts. Since then, it has caused severe damage in this region, especially to coconut (Cocos nucifera L.). It was first found in Brazil in 2009, in the northern Amazonian state of Roraima. In the present study, native and introduced plants were sampled between March 2010 and February 2011 in sites of the 15 Roraima municipalities, to estimate its distribution and the associated mite fauna. In addition, monthly samples were taken from a coconut plantation in Mucajai throughout the same period, for an initial appraisal of the levels R. indica could reach. It was found in 10 municipalities, on 19 plant species of four families. Six species are reported for the first time as hosts. Among the associated predators, 89.1% were Phytoseiidae, most commonly Amblyseius largoensis (Muma), Iphiseiodes zuluagai Denmark & Muma and Euseius concordis (Chant). The highest densities of R. indica, 1.5 and 0.35 mites/cm2 of leaflet (approx total of 331 and 77 mites/leaflet), were reached respectively in March 2010 and February 2011. The highest density of phytoseiids on coconut (0.009 mites/cm2 or about 2 mites/leaflet) was reached in November 2010. The average densities of R. indica recorded for Roraima were comparable to those reported for countries in which the mite is reportedly economically damaging. The dispersal of R. indica through the Amazon forest may result in damage to cultivated and native palms, and plants of other families, if the projected increase in both the frequency and the severity of drought events occurs. Parts of the Amazon have undergone periods of low rainfall, a condition that appears to favour the biology of this mite. Its eventual arrival to northeastern Brazil may result in heavy economic and ecological losses.

Demographic effects of thatch harvest and implications for sustainable use of irapai palm (Lepidocaryum tenue, Mart.), by riverine communities in the Peruvian Amazon

Lepidocaryum tenue Mart. (Arecaceae) is a small, understory palm of terra firme forests of the western and central Amazon basin. Known as irapai, it is used for roof thatch by Amazonian peoples who collect its leaves from the wild and generate income from its fronds and articles fabricated from them. Increasing demand has caused local concern that populations are declining. Cultivation attempts have been unsuccessful. The purpose of this study was to investigate market conditions and quantify population dynamics and demographic responses of harvested and unharvested irapai growing near Iquitos, Peru. ^ Ethnobotanical research included participant surveys to determine movement of thatch tiles, called crisnejas, through Moronacocha Port. I also conducted a seed germination trial, and for four years studied five populations growing in communities with similar topography and soils but different land tenure and management strategies. Stage, survival, leaf production, and reproductive transitions were used to calculate ramet demographic rates and develop population projection matrices. ^ Weavers made an average of 20–30 crisnejas per day (90–130 leaves each), and earned US$0.09 to 0.70 each (US$1.80 to 21.00 per day). Average crisnejas per month sold per vendor was 2,955 with a profit range of US$0.05 to 0.32 per crisneja. Wholesalers worked with capital outlay from US$100 to 400, and an estimated ten to twenty vendors could be found at a given time. Consumers paid between US$0.23 to 1.20 per crisneja. Although differences in demographic rates by location existed, most were not significant enough to attribute to management. ^ After 60 months, mean seed germination rate was 19.5% in all media (37.9% in peat). Seedling survival was less than two percent after twelve months. Annual palm mortality was three percent, and occurred disproportionately in small (<50 cm) palms. Small palms grew more in height. Unharvested palms grew less than harvested palms. Large palms (≥50 cm) produced more leaves, were more likely to reproduce, and collectors harvested them more frequently. Reproductive potentials (sexual and asexual) were low. Population growth rates were greater than or not significantly different from 1.0, indicating populations maintained or increased in size. Current levels of irapai harvest appear sustainable. DNA analysis of stems and recruits is recommended to understand population composition and stage-specific asexual fecundity. ^