Fruits of the Amazonian Forest. Part II: Sapotaceae

Descriptions and line drawings of fruits and seeds from 153 woody species of the family Sapotaceae occurring in Amazonia are presented, along with their preferred habitat, distribution, habit and seed dispersal.

On the influences of the El Niño, La niña and Atlantic Dipole Paterni on the Amazonian Rainfall during 1960-1998

The influence of the large-scale climatic variability dominant modes in the Pacific and in the Atlantic on Amazonian rainfall is investigated. The composite technique of the Amazon precipitation anomalies is used in this work. The basis years for these composites arc those in the period 1960-1998 with occurrences of extremes in the Southern Oscillation (El Niño or La Niña) and the north/south warm (or cold) sea surface temperature (SST) anomalies dipole pattern in the tropical Atlantic. Warm (cold) dipole means positive (negative) anomalies in the tropical North Atlantic and negative (positive) anomalies in the tropical South Atlantic. Austral summer and autumn composites for extremes in the Southern Oscillation (El Niño or La Niña) and independently for north/south dipole pattern (warm or cold) of the SST anomalies in the tropical Atlantic present values (magnitude and sign) consistent with those found in previous works on the relationship between Amazon rainfall variations and the SST anomalies in the tropical Pacific and Atlantic. However, austral summer and autumn composites for the years with simultaneous occurrences of El Niño and warm north/south dipole of the SST anomalies in the tropical Atlantic show negative precipitation anomalies extending eastward over the center-eastern Amazon. This result indicates the important role played by the tropical Atlantic in the Amazon anomalous rainfall distribution.

Seasonal changes of leaf Nitrogen content in trees of Amazonian floodplains

In Amazonian floodplains the trees are exposed to extreme flooding of up to 230 days a year. Waterlogging of the roots and stems affects growth and metabolic activity of the trees. An increased leaf fall in the aquatic period and annual increment rings in the wood indicate periodical growth reductions. The present study aims at documenting seasonal changes of metabolism and vitality of adult trees in the annual cycle as expressed by changes of leaf nitrogen content. Leaves of six tree species common in floodplains in Central Amazonia and typical representants of different growth strategies were collected every month between May 1994 and June 1995 in the vicinity of Manaus, Brazil. Mean leaf nitrogen content varied between 1.3% and 3.2% in the non-flooded trees. Three species showed significantly lower Ν content in the flooded period (p=0.05, 0.001, 0.001), the difference ranging 20-25% lower than in the non-flooded period. Two species showed no significant difference while Nectandra amazonum showed 32% more Ν in the flooded season (p=0.001). Leaf nitrogen content was generally high when new leaves were flushed (in the flooded period) and decreased continuously thereafter in all species. Three species showed an additional peak of nitrogen during the first month of the terrestrial phase, in leaves which had flushed earlier, indicating that flooding may disturb nitrogen uptake.

Floristic composition and diversity of Amazonian rainforest bryophytes in the state of Acre, Brazil

Bryophyte diversity in Amazonian Brazil is high, presently recorded at 514 species distributed among 36 families and 89 genera. Comparisions of species richness among the Amazonian states of Brazil suggests that the bryoflora of Acre is still underestimated, presently recorded at 106 species distributed among 33 families and 63 genera. After two field trips, the diversity increased 50% showing that the bryoflora is still poorly known. Collection data and comments on morphology, ecology and distribution are given for sixty-two species of bryophytes collected in the state of Acre, Brazil, which are new (fifty-two species) or interesting floristic records (ten species). Microlejeunea crenulifolia (Gottsche) Steph. and Stictolejeunea balfourdii Mitt. are new records for Brazil and fifty species are new records for Acre.

Structure and composition of the ground-herb community in a terra-firme Central Amazonian forest

The herb community of tropical forests is very little known, with few studies addressing its structure quantitatively. Even with this scarce body of information, it is clear that the ground herbs are a rich group, comprising 14 to 40% of the species found in total species counts in tropical forests. The present study had the objective of increasing the knowledge about the structure and composition of the ground-herb community and to compare the sites for which there are similar studies. The study was conducted in a tropical non-inundated and evergreen forest 90 km north of Manaus, AM. Ground herbs were surveyed in 22 transects of 40 m², distributed in five plots of 4 ha. The inventoried community was composed of 35 species, distributed in 24 genera and 18 families. Angiosperms were represented by 8 families and Pteridophytes by 10 families. Marantaceae (12 sp) and Cyperaceae (4 sp) were the richest families. Marantaceae and Poaceae were the families with greatest abundance and cover. Marantaceae, Poaceae, Heliconiaceae and Pteridophytes summed 96% of total herb cover, and therefore were responsible for almost all the cover of the community. The 10 most important species had 83.7% of the individuals. In general, the most abundant species were also the most frequent. Richness per transect varied from 7 to 19 species, and abundance varied from 30 to 114 individuals. The community structure was quite similar to 3 other sites in South America and one site in Asia.

Dispersal of seeds of Hymenaea courbaril (Fabaceae) in a logged rain forest in the Peruvian Amazonian

Seed dispersal of Hymenaea courbaril was studied by following the fate of 585 seeds embedded with small magnets and set in displays in and near a logged strip in rain forest in the Peruvian Amazonian. Mammals took fruits from all displays, which were located in the forest, edge, and cleared strip. Overall removal rates were low - a median of 8.1 fruits / month from displays maintained with 8-10 fruits - but were higher in August than in earlier months. Most fruits were dropped near the display or had their seeds eaten, but > 13% were successfully dispersed. Most of the dispersed seeds were buried, which increases probability of germination. Maximum dispersal distance of live seeds was 12.1 m (median 3.1 m), but other magnets were transported up to 34 m, indicating seeds were dispersed further, but then eaten. Acouchies (most likely Myoprocta pratti) and agoutis (Dasyprocta fuliginosa) were apparently the main dispersal agents. Dispersal of seeds from the forest into the logged strip was rare, suggesting that although rodents disperse H. courbaril, they cannot be relied on for the reseeding this and similar species in recent clearings.

Modelling Amazonian forest eddy covariance data: a comparison of big leaf versus sun/shade models for the C-14 tower at Manaus I. Canopy photosynthesis

In this study, we concentrate on modelling gross primary productivity using two simple approaches to simulate canopy photosynthesis: "big leaf" and "sun/shade" models. Two approaches for calibration are used: scaling up of canopy photosynthetic parameters from the leaf to the canopy level and fitting canopy biochemistry to eddy covariance fluxes. Validation of the models is achieved by using eddy covariance data from the LBA site C14. Comparing the performance of both models we conclude that numerically (in terms of goodness of fit) and qualitatively, (in terms of residual response to different environmental variables) sun/shade does a better job. Compared to the sun/shade model, the big leaf model shows a lower goodness of fit and fails to respond to variations in the diffuse fraction, also having skewed responses to temperature and VPD. The separate treatment of sun and shade leaves in combination with the separation of the incoming light into direct beam and diffuse make sun/shade a strong modelling tool that catches more of the observed variability in canopy fluxes as measured by eddy covariance. In conclusion, the sun/shade approach is a relatively simple and effective tool for modelling photosynthetic carbon uptake that could be easily included in many terrestrial carbon models.

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.

Chemical composition and acaricidal activity of the leaf and fruit essential oils of Protium heptaphyllum (Aubl.) Marchand (Burseraceae)

Essential oils from leaves and fruits of Protiumheptaphyllum collected in Tamandaré beach Pernambuco/Brazil were analysed by GC/MS and tested for toxicity and repellent effect against the two spotted spider mite (Tetranychus urticae). The major constituent identified in the fruits was alpha-terpinene (47.6 %) whereas oil from leaf contained mainly sesquiterpenes such as 9-epi-caryophyllene (21.4 %), trans-isolongifolanone (10.7 %) and 14-hydroxi-9-epi-caryophyllene (16.7 %). The fruit oil was found to be more effective against the mite when compared to the leaf oil. Both showed mortality properties and oviposition deterrence in higher concentration (10 µl.l-1 air), but only the essential oil from fruits induced repellence on T. urticae.

Treetop shelter of a neotropical river otter cub (Lontra longicaudis - Carnivora: Mustelidae) in an Amazonian flooded forest

The finding of a Neotropical river otter (Lontra longicaudis) cub occupying a shelter in a hollowed treetop is reported. The observation was made in a seasonally flooded forest in Central Amazonia, during the high water peak of the annual inundation cycle. A literature review indicates that this is the first description of a shelter of the species, both in a hollowed tree and in Amazonia. This observation can indicate a strong relationship between the species' breeding cycle with the annual dynamics of Amazonian rivers. We discuss potential advantages and disadvantages of breeding when water level is high.

Soil mineral N dynamics beneath mixtures of leaves from legume and fruit trees in Central Amazonian multi-strata agroforests

Long term applications of leguminous green mulch could increase mineralizable nitrogen (N) beneath cupuaçu trees produced on the infertile acidic Ultisols and Oxisols of the Amazon Basin. However, low quality standing cupuaçu litter could interfere with green mulch N release and soil N mineralization. This study compared mineral N, total N, and microbial biomass N beneath cupuaçu trees grown in two different agroforestry systems, north of Manaus, Brazil, following seven years of different green mulch application rates. To test for net interactions between green mulch and cupuaçu litter, dried gliricidia and inga leaves were mixed with senescent cupuaçu leaves, surface applied to an Oxisol soil, and incubated in a greenhouse for 162 days. Leaf decomposition, N release and soil N mineralization were periodically measured in the mixed species litter treatments and compared to single species applications. The effect of legume biomass and cupuaçu litter on soil mineral N was additive implying that recommendations for green mulch applications to cupuaçu trees can be based on N dynamics of individual green mulch species. Results demonstrated that residue quality, not quantity, was the dominant factor affecting the rate of N release from leaves and soil N mineralization in a controlled environment. In the field, complex N cycling and other factors, including soil fauna, roots, and microclimatic effects, had a stronger influence on available soil N than residue quality.

Analysis of toxicity on Bacillus sphaericus from amazonian soils to Anopheles darlingi and Culex quinquefasciatus larvae

Bioassays under laboratory conditions aiming to determine the larvicidal activity of Bacillus sphaericus were carried out on Anopheles darlingi and Culex quinquefasciatus. In order to estimate the toxicity through median lethal concentration (LC50) and the relative potency of the strains to B. sphaericus standard strain 2362, probit analysis was performed utilizing the POLO-PC program. The findings of LC50 pointed out high effectiveness on strains IB15 (0.040 ppm), IB19 and S1116 (0.048 ppm), IB16 (0.052 ppm) and S265 (0.057 ppm). Strain IB15 presented nearly 50% more potency than strain 2362 in bioassays conducted on A. darlingi. It was observed that IB16 and S1116 strains were the most powerful against C. quinquefasciatus, showing to be about 300-400% stronger than 2362 strain. The results show that laboratory conditioned evaluation can be an important way to select promising bacteria with entomopathogenic action on biolarvicides production for use on mosquitoes breeding sites.

Tolerance to temperature, pH, ammonia and nitrite in cardinal tetra, Paracheirodon axelrodi, an amazonian ornamental fish

Poor water quality condition has been pointed out as one of the major causes for the high mortality of ornamental fishes exported from the state of Amazonas, Brazil. The purpose of the current study was to define water quality standards for cardinal tetra (Paracheirodon axelrodi), by establishing the lower and higher for lethal temperature (LT50), lethal concentration (LC50) for total ammonia and nitrite and LC50 for acid and alkaline pH. According to the findings, cardinal tetra is rather tolerant to high temperature (33.3 ºC), to a wide pH range (acid pH=2.9 and alkaline pH=8.8) and to high total ammonia concentration (23.7 mg/L). However, temperatures below 19.6 ºC and nitrite concentrations above 1.1 mg/L NO2- may compromise fish survival especially during long shipment abroad.

On line pre-concentration for simultaneous determination of low molecular weight organic acids and inorganic anions in Amazonian river water samples employing ion chromatography with conductivity detection

An ion chromatography procedure, employing an IonPac AC15 concentrator column was used to investigate on line preconcentration for the simultaneous determination of inorganic anions and organic acids in river water. Twelve organic acids and nine inorganic anions were separated without any interference from other compounds and carry-over problems between samples. The injection loop was replaced by a Dionex AC15 concentrator column. The proposed procedure employed an auto-sampler that injected 1.5 ml of sample into a KOH mobile phase, generated by an Eluent Generator, at 1.5 mL min-1, which carried the sample to the chromatographic columns (one guard column, model AG-15, and one analytical column, model AS15, with 250 x 4mm i.d.). The gradient elution concentrations consisted of a 10.0 mmol l-1 KOH solution from 0 to 6.5 min, gradually increased to 45.0 mmol l-1 KOH at 21 min., and immediatelly returned and maintained at the initial concentrations until 24 min. of total run. The compounds were eluted and transported to an electro-conductivity detection cell that was attached to an electrochemical detector. The advantage of using concentrator column was the capability of performing routine simultaneous determinations for ions from 0.01 to 1.0 mg l-1 organic acids (acetate, propionic acid, formic acid, butyric acid, glycolic acid, pyruvate, tartaric acid, phthalic acid, methanesulfonic acid, valeric acid, maleic acid, oxalic acid, chlorate and citric acid) and 0.01 to 5.0 mg l-1 inorganic anions (fluoride, chloride, nitrite, nitrate, bromide, sulfate and phosphate), without extensive sample pretreatment and with an analysis time of only 24 minutes.

A first evaluation on the use of Ardea albus feathers as bioindicators of mercury burden in Amazonian ecosystems

We evaluated in this study the total mercury concentration in feathers of Ardea albus collected in a colony located in the city of Belem-PA, Brazil in a prospective trial for its use as bioindicators of mercury burden in Amazonia ecosystems. An Atomic absorption spectrophotometry with gold amalgamation was used for the metal determination. The total mercury average concentration in body feathers was 2.2 ± 1.5 µg.g-1 and 1.3 ± 0.9 µg.g-1 in wing feathers. No correlation was observed between total mercury concentration and the length of body or wing feathers. Total mercury concentration was above 5 µg.g-1 dry weight in only one body feather sample.