Throughfall and soil properties in shaded and unshaded coffee plantations and a secondary forest: a case study from Southern Colombia

In Colombia coffee production is facing risks due to an increase in the variability and amount of rainfall, which may alter hydrological cycles and negatively influence yield quality and quantity. Shade trees in coffee plantations, however, are known to produce ecological benefits, such as intercepting rainfall and lowering its velocity, resulting in a reduced net-rainfall and higher water infiltration. In this case study, we measured throughfall and soil hydrological properties in four land use systems in Cauca, Colombia, that differed in stand structural parameters: shaded coffee, unshaded coffee, secondary forest and pasture. We found that throughfall was rather influenced by stand structural characteristics than by rainfall intensity. Lower throughfall was recorded in the shaded coffee compared to the other systems when rain gauges were placed at a distance of 1.0 m to the shade tree. The variability of throughfall was high in the shaded coffee, which was due to different canopy characteristics and irregular arrangements of shade tree species. Shaded coffee and secondary forest resembled each other in soil structural parameters, with an increase in saturated hydraulic conductivity and microporosity, whereas bulk density and macroporosity decreased, compared to the unshaded coffee and pasture. In this context tree-covered systems indicate a stronger resilience towards changing rainfall patterns, especially in mountainous areas where coffee is cultivated.

Reducing competition in agroforestry by pruning native trees.

The degree to which pruning helps reestablish balance in agroforestry was assessed in a system established in São Carlos, São Paulo, Brazil, in 2008. Seven native tree species were planted at a density of 600 trees/ha in five strips of three rows each, and annual crops were cultivated in the 17-m crop strips between the tree strips. Competition was established after 35 months, decreasing the aboveground biomass production of corn planted close to the trees. An assessment of black oats in the dry season following tree pruning showed that the proximity of trees caused reductions in plant and panicle density, aboveground biomass production, number of grains per panicle and grain weight. Because pruning was not sufficient to maintain crop yields, tree thinning is recommended in order to minimize competition and restore conditions for adequate crop production.

Investigating genetic diversity in sapucaia using inter simple sequence repeat markers.

Sapucaia is a tree species originating from the Brazilian Amazon and is widely distributed in Brazil, especially in the mid-north region (Piauí and Maranhão states). Its seeds are rich in calories and proteins, and possess great potential for commercialization. Little is known about the genetic variability in the germplasm of most Lecythis species.

Regeneration in felling gaps after logging in Acre state, Western Amazon.

Regeneration of tree species in felling gaps were studied during the first two years following harvesting in a tropical forest in Acre state, Brazil. Felling gaps averaged 340 m2 in size, while canopy openings averaged 17%. Seedling mortality in adjacent undisturbed forest was 4.6% yr', and 59.6% yr·1 and 100% yr' in the crown and trunk zones respectively, two years after logging. Recruitment of new seedlings inthe undisturbed forest understorey averaged 462 plants ha' yr', two years after gap creation. Inthe crown zones of the gaps, recruitment of seedlings averaged 1350 ha' yr', and in the trunk zones 1392 ha' yr'. The entire seedling community in trunk zones after logging was composed of new recruits. lhere was a tendency for seedling growth rates to increase from the natural forest (0,21cm yr-1) to the crown zone (0.40cm yr'), Before gap creation, species richness and diversity and seedling density were quite similar. After gap creation a sharp decrease could be verified in the gap.zones, however the differences between gap and undisturbed forest decreased rapidly in the second year after gap creation. lhe regeneration of commercial species was not affected by gap creation apart from the increase in growth rates.

Growth of native trees in two agroforestry systems.

Agroforestry systems with eucalyptus prevail in Central and Southeast Brazil, and little information is available about systems using native trees. The aim of the present study was to evaluate the development of seven native tree species grown under two agroforestry systems. The experiment was conducted starting in 2007 in 12-hectare area in the municipality of São Carlos, São Paulo state, Brazil. The tree species planted in the two systems (a silvopastoral system and an agrisilvicultural system) were: 'capixingui' (Croton floribundus) and 'mutambo' (Guazuma ulmifolia) (tutors), 'jequitibá-branco' (Cariniana estrellensis), 'canafistula' (Peltophorum dubium) and 'ipê felpudo' (Zeyheria tuberculosa) (timber trees), and 'angico-branco' (Anadenanthera colubrina) and 'pau-jacaré' (Piptadenia gonoacantha) (N-fixing trees). Data were collected for 48 months. The results show differences among tree development, which was evaluated as growth in height and diameter, as well as sensitivity to insect and disease damage. The overall results show that the agrisilvicultural system allowed better tree development. The species with best performance in the two systems were capixingui, mutambo and canafístula. Ipê-felpudo and jequitibá-branco showed the worst results. The high variability among individuals of the same species indicates the possibility of high production advances with selective breeding of these species.

Metodologia para medição da potência necessária ao corte por um triturador florestal.

Resumo: Para execução do processo de raleamento na Caatinga é importante utilizar máquinas do tipo rotores trituradores acoplados em tratores de baixa potência, visando a diminuição de tempo e mão-de-obra dos agricultores familiares na, implantação de sistemas de exploração sustentáveis, sistemas agrossilvipastoris. Para o projeto de uma máquina que seja acessível a estes produtores, o primeiro passo é se conhecer a potência de corte necessária para a operação de raleamento. O objetivo deste trabalho foi desenvolver e avaliar uma metodologia de ensaio para medir a potência durante o corte de uma espécie arbórea, podendo assim avaliar os parâmetros a serem utilizados futuramente no projeto da máquina. Como espécie teste, utilizou-se o eucalyptus citriodora, por ser uma madeira que apresenta resistência de corte elevada e similar ao das espécies da Caatinga. Observou-se que a metodologia proposta, ao padronizar os procedimentos, permitiu adquirir de forma rápida e precisa os valores dos parâmetros de importância no projeto de máquinas destinadas a cortar e triturar espécies arbóreas. Também a utilização dos dados obtidos por meio da aplicação da metodologia, possibilitam maior confiabilidade e precisão no projeto de máquinas destinadas a este tipo de trabalho. [Methodology for obtaining the cutting power of a forest crusher]. Abstract: For executions the thinning process in Caatinga is important to use machines as Rotors Crushers coupled in low- power tractors, aimed at decrease of time and hand labor of Family Farmers in the implementation of sustainable exploration systems, agrosylvopastoral Systems. For the project for the design of a machine that is accessible these producers, the first step is knowing the cut power needed for a thinning operation. The objective of this study was to develop and evaluate a test methodology to measure the power during the cutting of a tree species and can evaluate the cutting parameters used in the future in machine design. As a test species, we used the eucalyptus citriodora, as this wood has cut high resistance and similar to Species of Caatinga. It was observed that the methodology proposal, to the standardize procedures, allows to get quickly and accurately the values of importance parameters in the design of machines designed to cut and grind tree species. Also the use of data obtained through the application of the methodology , enable greater reliability and precision in machine design intended for this type of work.

Habitat use by a tree frog species of Scinax (Amphibia, Hylidae) at an urban forest fragment from south-eastern Brazil

We studied the pattern of habitat use by the tree frog Scinax aff. perereca. Fieldworks were performed from August 1996 to August 1997 at Parque das Mangabeiras, Belo Horizonte, State of Minas Gerais, southeastern Brazil. Calling males were observed in September, October and December 1996, February to April and June 1997. Females were found only in October 1996. Specimens were found perched on vegetation, on the ground or on stones near waterfall. At Parque das Mangabeiras, S. aff. perereca occupied nine types of substrata. The most frequently used substrata were shrubs, stones at the stream edges, and fallen trunks. The pattern of spatial occupation varied among months. Males were found calling in aggregations on the vegetation and spatial niche breadth was related to species abundance.

Aspects of classification of Hemiptera hemocytes from six triatomine species

The objective of this work was to characterize, and compare different morphological types of hemocytes of Rhodnius prolixus, Rhodnius, Rhodnius neglectus, Triatoma infestans, Panstrongylus megistus, and Dipetalogaster maximus. This information provides the basis for studying the cellular immune systems of these insects. Seven morphological hemocyte types wereidentified by phase-contrast microscopy: prohemocytes, plasmatocytes, granular cells, cytocytes, oenocytoids, adipohemocytes and giant cells. All seven types of hemocytes are not present in every species. For example, adipohemocytes and oenocytoids were not observed in P. megistus and P. infestans, and giant cells were rarely found in any of the species studied. The hemocytes of rhodnius and Dipetalogaster are more similar to each other than those from Triatoma and Panstrongylus which in turn closely resemble each other. Emphasis is placed on methodological problems arising in this work wicah are discussed in detail.

Characterization of Endotrypanum (Kinetoplastida: Trypanosomatidae), a Unique Parasite Infecting the Neotropical Tree Sloths (Edentata)

This article reviews current concepts of the biology of Endotrypanum spp. Data summarized here on parasite classification and taxonomic divergence found among these haemoflagellates come from our studies of molecular characterization of Endotrypanum stocks (representing an heterogenous population of reference strains and isolates from the Brazilian Amazon region) and from scientific literature. Using numerical zymotaxonomy we have demonstrated genetic diversity among these parasites. The molecular trees obtained revealed that there are, at least, three groups (distinct species?) of Endotrypanum, which are distributed in Central and South America. In concordance with this classification of the parasites there are further newer molecular data obtained using distinct markers. Moreover, comparative studies (based on the molecular genetics of the organisms) have shown the phylogenetic relationships between some Endotrypanum and related kinetoplastid lineages.

Multilocus sequence analysis reveals the genetic diversity of European fruit tree phytoplasmas and supports the existence of inter-species recombination

The genetic diversity of three temperate fruit tree phytoplasmas ‘Candidatus Phytoplasma prunorum’, ‘Ca. P. mali’ and ‘Ca. P. pyri’ has been established by multilocus sequence analysis. Among the four genetic loci used, the genes imp and aceF distinguished 30 and 24 genotypes, respectively, and showed the highest variability. Percentage of substitution for imp ranged from 50 to 68% according to species. Percentage of substitution varied between 9 and 12% for aceF, whereas it was between 5 and 6% for pnp and secY. In the case of ‘Ca P. prunorum’ the three most prevalent aceF genotypes were detected in both plants and insect vectors, confirming that the prevalent isolates are propagated by insects. The four isolates known to be hypo-virulent had the same aceF sequence, indicating a possible monophyletic origin. Haplotype network reconstructed by eBURST revealed that among the 34 haplotypes of ‘Ca. P. prunorum’, the four hypo-virulent isolates also grouped together in the same clade. Genotyping of some Spanish and Azerbaijanese ‘Ca. P. pyri’ isolates showed that they shared some alleles with ‘Ca. P. prunorum’, supporting for the first time to our knowledge, the existence of inter-species recombination between these two species.

Effects of timber harvest on phlebotomine sand flies (Diptera: Psychodidae) in a production forest: abundance of species on tree trunks and prevalence of trypanosomatids

The Amazon forest is being exploited for timber production. The harvest removes trees, used by sand flies as resting sites, and decreases the canopy, used as refuges by some hosts. The present study evaluated the impact of the timber harvest, the abundance of sand flies, and their trypanosomatid infection rates before and after selective logging. The study was accomplished in terra-firme production forest in an area of timber harvest, state of Amazonas, Brazil. Sand fly catches were carried out in three areas: one before and after the timber harvest, and two control areas, a nature preservation area and a previously exploited area. The flies were caught by aspiration on tree trunks. Samples of sand flies were dissected for parasitological examination. In the site that suffered a harvest, a larger number of individuals was caught before the selective extraction of timber, showing significant difference in relation to the number of individuals and their flagellate infection rates after the logging. The other two areas did not show differences among their sand fly populations. This fact is suggestive of a fauna sensitive to the environmental alterations associated with selective logging.