Otimização da rede de estradas secundárias em projetos de manejo sustentável de floresta tropical.

A otimização da rede de estradas secundárias em função das distâncias ideais de arraste não tem sido considerada na elaboração dos planos de manejo de floresta tropical. No Estado do Acre, as florestas com potencial de manejo, possuem diferentes tipologias, volume comercial e potencialmente aproveitáveis por hectare, topografia e solos variados. Isto implicará sempre diferentes densidades ideais de construção de estradas florestais para manejo, tornando necessária a utilização de metodologia que defina o menor custo e dano ao povoamento. Este trabalho tem a finalidade de fornecer suporte técnico à planificação de redes de estradas para o manejo em florestas tropicais, abordando os principais elementos necessários as planejamento e sugerindo uma sistemática de trabalhos para elaboração de um projeto.

Planejamento de arraste mecanizado em floresta tropical.

Este trabalho visa basicamente sugerir uma sequência de metodológica de trabalho para o planejamento adequado do arraste mecanizado, baseado no proposto em Braz & Oliveira (1996), e métodos existentes.

Biologia da lagarta-do-paricá Syssphinx molina (Cramer, 1780) (Lepidoptera: Saturniidae) em dietas artificiais e naturais in vitro.

2015

Ataque de Lonomia sp. (Lepidoptera: Saturniidae) em seringueira no município de Bujari, AC.

Os estudos dos insetos associados às culturas agrícolas e florestais são dinâmicos, em função da evolução dos sistemas de cultivo, do avanço da fronteira agrícola, da introdução de novas pragas e da resistência aos produtos químicos historicamente aplicados. Nesse contexto, os avanços nos estudos dos insetos-praga periodicamente precisam ser integrados em publicações de referência, que permitam fácil acesso a esses conhecimentos. Assim, o objetivo desta publicação é documentar o ataque de lagartas do gênero Lonomia, popularmente conhecidas como lagartas-de-fogo, causando intensa desfolha em cultivos de seringueira (Hevea brasiliensis) no Acre. Há um grande número de trabalhos publicados sobre esse gênero, no que tange aos problemas acarretados pelo contato direto de pessoas com as lagartas, provocando acidentes hemorrágicos graves, dependendo da área lesionada e da extensão do contato. No entanto, não havia relatos dessas lagartas causando intenso desfolhamento em seringais de cultivo, ocasionando prejuízos econômicos. A partir da intensificação do cultivo, surtos populacionais de insetos, considerados pragas secundárias em muitas culturas, podem acontecer com mais frequência, necessitando de conhecimento e estratégias de manejo que visem ao monitoramento, distribuição e controle de populações de insetos no Estado do Acre, a fim de prevenir surtos populacionais de pragas e, consequentemente, prejuízos elevados aos produtores acrianos.

Rapid Losses of Surface Elevation following Tree Girdling and Cutting in Tropical Mangroves.

Discussion Conclusions Materials and Methods Acknowledgments Author Contributions References Reader Comments (0) Figures Abstract The importance of mangrove forests in carbon sequestration and coastal protection has been widely acknowledged. Large-scale damage of these forests, caused by hurricanes or clear felling, can enhance vulnerability to erosion, subsidence and rapid carbon losses. However, it is unclear how small-scale logging might impact on mangrove functions and services. We experimentally investigated the impact of small-scale tree removal on surface elevation and carbon dynamics in a mangrove forest at Gazi bay, Kenya. The trees in five plots of a Rhizophora mucronata (Lam.) forest were first girdled and then cut. Another set of five plots at the same site served as controls. Treatment induced significant, rapid subsidence (−32.1±8.4 mm yr−1 compared with surface elevation changes of +4.2±1.4 mm yr−1 in controls). Subsidence in treated plots was likely due to collapse and decomposition of dying roots and sediment compaction as evidenced from increased sediment bulk density. Sediment effluxes of CO2 and CH4 increased significantly, especially their heterotrophic component, suggesting enhanced organic matter decomposition. Estimates of total excess fluxes from treated compared with control plots were 25.3±7.4 tCO2 ha−1 yr−1 (using surface carbon efflux) and 35.6±76.9 tCO2 ha−1 yr−1 (using surface elevation losses and sediment properties). Whilst such losses might not be permanent (provided cut areas recover), observed rapid subsidence and enhanced decomposition of soil sediment organic matter caused by small-scale harvesting offers important lessons for mangrove management. In particular mangrove managers need to carefully consider the trade-offs between extracting mangrove wood and losing other mangrove services, particularly shoreline stabilization, coastal protection and carbon storage.

Selección de un aislado del nucleopoliedrovirus de Helicoverpa armigera (HearNPV) para su uso como base de un bioinsecticida

Helicoverpa armigera (Lepidoptera; Noctuidae), conocida como el taladro del tomate, es una especie polífaga y de amplia distribución, responsable de grandes pérdidas económicas en más de 60 cultivos a lo largo de las regiones tropicales y subtropicales del mundo. Estas plagas se controlan mayoritariamente con plaguicidas químicos, aunque existe un gran interés por desarrollar otros agentes de control biológico. Entre estos, se encuentra el nucleopoliedrovirus de Helicoverpa armigera (HearNPV, Baculoviridae), que por sus características de seguridad y eficacia, sería útil para impulsar los programas de gestión integrada de plagas que se fomentan desde la Directiva 2009/128/CEE. El objetivo de este trabajo fue realizar una caracterización bioquímica y biológica de varios aislados de HearNPV : un aislado silvestre español (Badajoz) HearNPV-SP1, un aislado chino HearSNPV-G4, tres aislados sudafricanos (HearNPV-Whl, HearNPV-Kzn, HearNPV-Alb) y la materia activa de un producto comercial en uso en Europa (HearNPV-Hx). El análisis con las enzimas de restricción determinó que la enzima BglII generaba perfiles similares pero con fragmentos característicos en todos los casos a excepción de los aislados HearNPV-Kzn y HearNPVAlb, que no pudieron ser diferenciados entre sí con ninguna de las enzimas probadas. El análisis filogenético, basado en las secuencias parciales de los genes poliedrina (polh), lef-8 y lef-9, donde se incluyeron las secuencias correspondientes a 18 genomas mostró que el aislado HearNPV-Whl es filogenéticamente próximo a las cepas de origen ibérico, mientras que los aislados HearNPV-Hx y HearNPV-Alb comparten la misma rama que los aislados asiáticos y australiano. La caracterización insecticida de los aislados HearNPV-SP1, HearNPV-Hx y HearNPV-G4 reveló que la virulencia (TMM) del aislado HearNPV-SP1 (104 h) fue significativamente menor que la de los aislados HearNPV-G4 (109 h) y HearNPV-Hx (111 h). En este trabajo, se determinó que el tiempo de acción del HearNPV-SP1 es menor al de otros bioinsecticidas en uso en Europa, por lo que se confirma la posibilidad de mejorar los productos activos en uno de los aspectos más sensibles de cara a su comercialización como es su tiempo de actuación.

An Englishwoman's twenty-five years in tropical Africa: being the biography of Gwen Elen Lewis, missionary to the Cameroons and the Congo, by George Hawker

http://www.archive.org/details/anenglishwomanst00hawkuoft

Impact of the Interdecadal Pacific Oscillation on Tropical Cyclone Activity in the North Atlantic and Eastern North Pacific.

Tropical cyclones (TCs) are among the most devastating weather systems affecting the United States and Central America (USCA). Here we show that the Interdecadal Pacific Oscillation (IPO) strongly modulates TC activity over the North Atlantic (NA) and eastern North Pacific (eNP). During positive IPO phases, less (more) TCs were observed over NA (eNP), likely due to the presence of stronger (weaker) vertical wind shear and the resulting changes in genesis potential. Furthermore, TCs over NA tend to keep their tracks more eastward and recurve at lower latitudes during positive IPO phases. Such variations are largely determined by changes in steering flow instead of changes in genesis locations. Over the eNP, smaller track variations are observed at different IPO phases with stable, westward movements of TCs prevailing. These findings have substantial implications for understanding decadal to inter-decadal fluctuations in the risk of TC landfalls along USCA coasts.

Heat balances and thermally driven lagoon-ocean exchangeson a tropical coral reef system (Moorea, French Polynesia)

© 2015. American Geophysical Union. All Rights Reserved.The role of surface and advective heat fluxes on buoyancy-driven circulation was examined within a tropical coral reef system. Measurements of local meteorological conditions as well as water temperature and velocity were made at six lagoon locations for 2 months during the austral summer. We found that temperature rather than salinity dominated buoyancy in this system. The data were used to calculate diurnally phase-averaged thermal balances. A one-dimensional momentum balance developed for a portion of the lagoon indicates that the diurnal heating pattern and consistent spatial gradients in surface heat fluxes create a baroclinic pressure gradient that is dynamically important in driving the observed circulation. The baroclinic and barotropic pressure gradients make up 90% of the momentum budget in part of the system; thus, when the baroclinic pressure gradient decreases 20% during the day due to changes in temperature gradient, this substantially changes the circulation, with different flow patterns occurring during night and day. Thermal balances computed across the entire lagoon show that the spatial heating patterns and resulting buoyancy-driven circulation are important in maintaining a persistent advective export of heat from the lagoon and for enhancing ocean-lagoon exchange.

Biological and physical interactions on a tropical island coral reef: Transport and retention processes on moorea, French Polynesia

The Moorea Coral Reef Long Term Ecological Research project funded by the US National Science Foundation includes multidisciplinary studies of physical processes driving ecological dynamics across the fringing reef, back reef, and fore reef habitats of Moorea, French Polynesia. A network of oceanographic moorings and a variety of other approaches have been used to investigate the biological and biogeochemical aspects of water transport and retention processes in this system. There is evidence to support the hypothesis that a low-frequency counterclockwise flow around the island is superimposed on the relatively strong alongshore currents on each side of the island. Despite the rapid flow and flushing of the back reef, waters over the reef display chemical and biological characteristics distinct from those offshore. The patterns include higher nutrient and lower dissolved organic carbon concentrations, distinct microbial community compositions among habitats, and reef assemblages of zooplankton that exhibit migration behavior, suggesting multigenerational residence on the reef. Zooplankton consumption by planktivorous fish on the reef reflects both retention of reef-associated taxa and capture by the reef community of resources originating offshore. Coral recruitment and population genetics of reef fishes point to retention of larvae within the system and high recruitment levels from local adult populations. The combined results suggest that a broad suite of physical and biological processes contribute to high retention of externally derived and locally produced organic materials within this island coral reef system. © 2013 by The Oceanography Society. All rights reserved.

Relación entre la fragmentación del hábitat primario a escala de paisaje y la avifauna dependiente de bosque tropical en la región caribeña de Guatemala

El estudio de los efectos de la modificación del hábitat sobre la diversidad biológica tropical es un tema fundamental para la biología de la conservación. El objetivo principal de este trabajo fue evaluar el efecto de la modificación del bosque tropical a escala de paisaje, y en particular de la fragmentación del bosque, sobre las comunidades de aves en la región caribeña de Guatemala, e identificar los mecanismos ecológicos principales asociados a dichos efectos. Relevé las comunidades de aves en 123 paisajes, y estudié la relación entre: 1) la presencia de 10 especies blanco; 2) la riqueza, abundancia y composición de las aves dependientes de bosque; 3) la dinámica temporal de dicha comunidad; 4) la riqueza de ocho gremios ecológicos, y la variación en la composición y configuración del hábitat en estos paisajes, mediante modelos lineales generalizados y técnicas multivariadas. Concluí que: 1) la persistencia de las aves en paisajes modificados depende de factores que operan a escalas extra-territoriales; 2) el efecto de la cobertura de bosque sobre la comunidad de aves fue mayor, pero hubo fuertes respuestas a la fragmentación y aumentos del perímetro de las especies de interior de bosque, las granívoras, nectarívoras, e insectívoras residentes de follaje y hojarasca; 3) la dinámica comunitaria de los paisajes con cobertura mayor al 40 por ciento, independientemente del grado de fragmentación, fueron muy similares a la del bosque continuo; 4) las especies más vulnerables a la modificación poseen poca capacidad de utilizar hábitats alternativos, impidiendo la suplementación de recursos en éstos y/o restringiendo su dispersión a otros fragmentos; aquellas que se alimentan y anidan en los estratos inferiores del bosque y construyen nidos abiertos son más vulnerables a los efectos bióticos y abióticos de los bordes de bosque; las especies que son miembros comunes de grupos de alimentación son afectadas por mayores requerimientos de área y una menor amplitud de hábitat.

Aspectos de preferencia alimentaria de Plutella xylostella L. (Lepidoptera ; Yponomeutidae) en algunas cruciferas cultivadas

p.1-5

Monitoreo de once especies de noctuidos con trampas luminosas e influencia de factores ambientales sobre la dinámica poblacional de adultos de la oruga desgranadora Faronta albilinea (HBN) (Lepidoptera: Noctuidae)

p.157-163

Species diversity structure analysis at two sites in the tropical rain forest of Sumatra

Data from a hilly forest study site at Batang Ule, Sumatra, are organized into 30 100-m × 10-m subplots lying perpendicular to the line of maximal topographic gradient, from the valley to the plateau/ridge. The following methodological question is addressed: what species diversity measures are best used in order to reveal the ecologically distinct regions in the site. The main tool used to answer this question is the α-diversity curve (Hα). Graphical examination of tree and species densities, and α-diversity curves identifies an anomalous species diversity behaviour of the ‘ridge above the slope’ subplots which may have implications on land-facet class definitions. Factor analysis of the α-diversity curves indicates that the diversity space is two-dimensional: i.e. two diversity measures are sufficient to characterize the site; the species density (H0), and the Berger-Parker index (H[infty infinity]). In the two-dimensional diversity-space three distinct species diversity groups are found which relate to the topographic gradient at the Batang Ule site. The results are compared with those for a flat homogeneous site at Pasirmayang, Sumatra. The implications of the results on land-classifications in species-diversity mapping and conservation strategy are discussed.