bluuebunny/crossref_metadata_2025_split huggingface dataset:
Myrmecophagy in Mycetophiloidea (Diptera): Note on a Keroplatidae from Africa1,2
Authors: Debout Gabriel 
Published: March 2006

ABSTRACTInformation on an undescribed keroplatid fly (tribe Orfeliini) from Cameroon is presented. Its myrmecophagous larvae live in hollow stems of an understory myrmecophytic tree. Data on the biology of this fly and its interaction with one of the plant's strictly associated ant species Cataulacus mckeyi (Myrmicinae) showed that the number of keroplatid larvae per tree was not limited by occupation competition with the ant. Through predation on workers, keroplatid larvae may have a sizeable impact on colonies of C. mckeyi.RÉSUMÉNous préntons des informations sur une espèce non‐décrite de Keroplatidae (tribu Orfeliini), au Cameroun. Les larves myrmécophages se développent dans les tiges creuses 7dcarune myrmécophyte de sous‐bois. Des données sur la biologie de cette espèce et son interaction avec lcarune des fourmis‐h&#x006f;̧tes de cette plante, Cataulacus mckeyi, montrent que le nombre de larves par arbre n'est pas limité par la compétition pour lcaroccupation avec la fourmi. En prédatant les ouvrières, ces larves ont un impact potentiellement important sur les colonies de C. mckeyi.
Alien Abduction: Disruption of Native Plant‐Pollinator Interactions by Invasive Species
Authors: Ghazoul Jaboury 
Published: March 2006

ABSTRACTThe indirect impacts of Shorea siamensis‐logging on the reproductive ecology of Dipterocarpus obtusifolius, a self‐incompatible butterfly‐, moth‐, and bird‐pollinated tree, were studied in tropical dry forest in Thailand. Pollinator activity at D. obtusifolius trees and subsequent seed production were recorded in three forest areas subject to differing intensities of S. siamensis extraction. The pollinator and plant understory communities in these areas were also noted. Forest areas subject to high S. siamensis extraction intensities had very high understory flowering plant cover, dominated by the exotic invader Chromolaena odorata. Activity of butterfly pollinators at D. obtusifolius trees decreased in these disturbed areas, although their abundance remained comparable to other forest areas subject to only moderate or no extraction. For sphingid moth pollinators, there was no difference across differentially disturbed forest areas in either abundance or in the proportion bearing pollen. Pollinator activity by birds increased at highly disturbed locations but was not sufficient to offset a decline in overall pollinator activity at D. obtusifolius canopies in areas of heavy 5. siamensis extraction. Thus, extraction of S. siamensis indirectly affected the pollination of D. obtusifolius, primarily by causing changes in the foraging behavior of butterfly pollinators rather than their abundance. A shift in the relative abundance of floral nectar resources from the canopy to the understory, a consequence of 5. siamensis extraction and invasion by C. odorata, led to a parallel shift in foraging location of the principal diurnal pollinators, the butterflies, toward the understory. Despite reduced pollination at disturbed sites, behavioral changes did not translate into a D. obtusifolius seed set effect, possibly because pollination by birds (or moths) at the disturbed site compensated for reduced butterfly pollination.
Extracellular Enzyme Activities and Carbon Chemistry as Drivers of Tropical Plant Litter Decomposition
Authors: Allison Steven D. , Vitousek Peter M. 
Published: March 2006

ABSTRACTLitter quality parameters such as nitrogen and lignin content correlate with decomposition rates at coarse scales, but fine‐scale mechanisms driving litter decomposition have proven more difficult to generalize. One potentially important driver of decomposition is the activity of extracellular enzymes that catalyze the degradation of complex compounds present in litter. To address the importance of this mechanism, we collected 15 Hawaiian plant litter types and decomposed them in fertilized and control plots for up to two years. We measured litter nutrient content and carbon chemistry prior to decomposition, as well as extracellular enzyme activities, mass loss, and litter nutrient content over time. We found that water‐soluble carbon content, cellobiohydrolase activities, and polyphenol oxidase activities were significantly correlated with mass loss. Enzyme activities and decomposition rate constants both varied significantly by litter type, and fertilization increased mass loss rates in five litter types. Some litter types that decayed faster under fertilization also showed time‐dependent increases in carbon‐degrading enzyme activities, but others decayed faster independent of enzyme changes. These results suggest that extracellular enzyme activities partially determine litter decomposition rates, but high soluble carbon content may circumvent the requirement for enzyme‐catalyzed decomposition.
Observations on the Ecology of Weaver Ants (Oecophylla smaragdina Fabricius) in a Thai Mangrove Ecosystem and Their Effect on Herbivory of Rhizophora mucronata Lam.
Authors: Offenberg Joachim , Havanon Sopon , Aksornkoae Sanit , Macintosh Donald J. , Nielsen Mogens Gissel 
Published: March 2006

ABSTRACTAnts of the genus Oecophylla are predators of other insects and are able to protect a variety of terrestrial plants against pest insects; however, observations on the ecology of these ants in mangrove forests are lacking. General observations on the ecology of Oecophylla smaragdina were carried out in a Thai mangrove forest to determine if these ants can protect their host plants in less favorable mangrove habitats. Leaf herbivory and the density of O. smaragdina ants were measured on Rhizophora mucronata trees at two sites. The results showed a negative correlation between ant density and herbivory. At both sites, the mean percent damaged leaf area was more than four times higher on trees without ants compared to “ant‐trees.” A significant negative correlation was found between tree mean percent leaf damage and the density of ants on the tree. Furthermore, on trees with ants, there was less herbivory on leaves close to ant nests compared to other leaves on the tree. Most damage was caused by chrysomelid beetles (62%) and sesarmid crabs (25%) and both types of herbivory were significantly reduced on ant‐trees.
Fruit, Minerals, and Forest Elephant Trails: Do All Roads Lead to Rome?
Authors: Blake Stephen , Inkamba‐Nkulu Clement 
Published: March 2006

ABSTRACTTropical forests are among the most heterogeneous environments on earth, and food resources for many animals are patchy both in time and space. In Africa's equatorial forest, permanent trails created and maintained by forest elephants are conspicuous features. Trails may be several meters wide and continue for tens of kilometers. Speculation on which resources determine the distribution of trails has identified fruit, browse, and mineral deposits as candidates. In this study, the relationships between these habitat variables and elephant trails were investigated. The size of individual trails and the density of the trail system increased dramatically with proximity to mineral deposits. Fruit tree basal area decreased with perpendicular distance from trails, while that of non‐fruit trees did not. Fruit tree abundance and basal area were significantly higher on trail intersections than random sites and increased with intersection size. No relationship was found between monocotyledon browse abundance and elephant trail system characteristics. Clumped resources, which are at least partially reliable, provide a high nutritional payback, and are not rapidly depleted and can thus be visited repeatedly, appear to influence permanent trail formation by forest elephants. Permanent trails may allow naive individuals or those with imperfect knowledge to locate and acquire important resources.
Arboreal Ant Species Richness in Primary Forest, Secondary Forest, and Pasture Habitats of a Tropical Montane Landscape1
Authors: Schonberg Lisa A. , Longino John T. , Nadkarni Nalini M. , Yanoviak Stephen P. , Gering Jon C. 
Published: March 2006

ABSTRACTCanopy invertebrates may reflect changes in tree structure and microhabitat that are brought about by human activities. We used the canopy fogging method to collect ants from tree crowns in primary forest, secondary forest, and pasture in a Neotropical cloud forest landscape. The total number of species collected was similar in primary forest (21) and pasture (20) habitats, but lower in secondary forest (9). Lower diversity in secondary forest was caused by lower species density (no. of species per sample). Rarefaction curves based on number of species occurrences suggest similar community species richness among the three habitats. This study has implications for conservation of tropical montane habitats in two ways. First, arboreal ant species density is reduced if secondary forest replaces primary forest, which increases the chance of extinction among rare species. Second, pasture trees may serve as repositories of primary forest ant communities due to similar tree structure.RESUMENLos disturbios antropogénicos sobre la estructura de los árboles y microhabitat afectara la diversidad de invertebrados del dosel. Se usó la técnica de fumigación para colectar hormigas de las copas de los árboles en tres ambientes en un bosque nuboso Neotropical; bosque primario, bosque secundario, y pastizal. La cantidad total de especies colectadas fue similar entre el bosque primario (21) y el pastizal (20), pero menor en el bosque secundario (9). La baja riqueza en el bosque secundario fue consequencia de menor densidad de especies (cantidad de especies por muestra). Las curvas de rarefacción basada en presencia/ausencia de especies sugieren que la riqueza a nivel de la comunidad es similar entre los tres tipos de hábitat. Estos resultados puede aportar a la conservación de los hábitat tropicales nubosos de dos maneras. Primero, sugieren que la densidad de especies de hormigas es baja cuando un bosque primario es reemplazado por un bosque secundario. Segundo, los árboles grandes de pastizales pueden servir como refugios para las comunidades de hormigas, debido a que presentan similitud con la estructura de un bosque primario.
Granivorous Birds as Potentially Important Post‐dispersal Seed Predators in a Brazilian Forest Fragment1
Authors: Pizo Marco A. , Vieira Emerson M. 
Published: March 2006

ABSTRACTIn tropical forests, rodents exert a prominent role as post‐dispersal seed predators, while other vertebrates apparently have a minor effect on seed predation. In some forest fragments in southeast Brazil, however, the density of rodents is unusually low, whereas terrestrial granivorous birds are abundant. In this study, we used seeds of a second‐growth tree (Cretan priscus, Euphorbiaceae) to investigate experimentally the relative importance of rodents and birds as seed predators in a forest fragment. We also estimated the density of terrestrial granivorous birds and trapped small mammals. Results indicate that, as a consequence of decreased rodent population and increased bird abundance, the latter are at least as important as the former as the main post‐dispersal seed predators ofC. priscus.We interpret such apparent imbalance in the interaction betweenC. priscusand their seed predators as a possible consequence of forest fragmentation.RESUMOEm florestas tropicals, enquanto os roedores figuram entre os principals predadores pós‐dispersão de sementes, outros vertebrados desempenham mais raramente este papel. Em alguns fragmentos da floresta no sudeste do Brasil, no entanto, a densidade de roedores é bastante baixa, enquanto aves granivoras terrestres são abundantes. Neste estudo nós usamos sementes de uma árvore caracterfstica de vegetaçáo secundaria (Croton priscus, Euphorbiaceae) para investigar experimentalmente a importancia relativa dos roedores e das aves granfvoras como predadores de sementes em um destes fragmentos da floresta. Concomitantemente também estimamos a densidade das aves granivoras e a abunda̧ancia de pequenos mamiferos. Os resultados obtidos indicaram que, como conseqüȩncia da baixa abunda̧ancia de roedores e alta abunda̧ncia de aves granivoras, estas sa̧o ao rnenos ta̧o importantes quanto os roedores como predadores pós‐dispersa̧o das sementes deC.priscus. Interpretamos este padra̧o pouco usual na interaça̧o enterC. priscuse os predadores de suas sementes como uma possivel conseqüȩnica da fragmentação floresta.
Decomposition of Greenfall vs. Senescent Foliage in a Tropical Forest Ecosystem in Puerto Rico1
Authors: Fonte Steven J. , Schowalter Timothy D. 
Published: March 2006

ABSTRACTIn many forest ecosystems, green leaf deposition (greenfall) constitutes an enrichment over background levels of litterfall nutrients and may therefore influence key ecosystem processes. This study examined the litter quality and decomposition rates of green leaves compared to senescent litterfall for four dominant tree species(Dacryodes excelsa, Manilkara bidentata, Guarea guidonia, andCecropia schreberiana)in a lower montane rain forest at El Verde Field Station, Luquillo Experimental Forest, Puerto Rico. Green leaves from the canopy and freshly senesced leaves from the forest floor were analyzed for carbon, nitrogen, and fiber and placed in litterbags in the field for up to 16 weeks. Green leaves displayed significantly higher rates of decomposition than did senescent litter among all four species. Green leaves also had significantly higher nitrogen concentrations and lower lignin to nitrogen ratios compared to senescent leaves. These results suggest that greenfall may have a major influence on decay processes and nutrient cycling in forests that experience large‐scale green foliage removal.RESUMENEn muchos ecosistemas forestales, la adición de hojas verdes constituye en altos niveles de enriquecimiento de nutrientes de hojarasca y por lo tanto puede influir en los procesos fundamentales de un ecosistema. Este estudio examina la calidad de hojarasca y la tasa de descomposición de hojas verdes comparado con hojas senescentes recién caidas de cuatro especies dominantes (Dacryodes excelsa, Manilkara bidentata, Guarea guidonia, y Cecropia schreberiana) en un bosque lluvioso montanoso bajo en la estación El Verde, Bosque Experimental de Luquillo, Puerto Rico. Hojas verdes de la copa de los árboles y hojas senescentes recién caidas en el suelo del bosque fueron analizadas para carbono, nitrógeno, y fibra, y fueron colocadas en bolsas de basura en el suelo del bosque por 16 semanas. Las hojas verdes mostraron tasas de descomposición significativamente mayores que la hojarasca senescente entre todas las cuatro especies. Las hojas verdes muestran significativamente mayores concentraciones de nitrógeno y menores relaciones de lignina‐nitrógeno comparado con las hojas senescentes. Estos resultados sugieren que la cafda de hojas verdes puede influir en forma significativa en los procesos de descomposici6n y ciclaje de nutrientes en bosques que experimentan a gran escala remoci6n de follaje verde.
Avian Geophagy and Soil Characteristics in Southeastern Peru
Authors: Brightsmith Donald J. , Muñoz‐Najar Romina Aramburú 
Published: March 2006

ABSTRACTWe observed ten species of psittacids, three species of columbids, and two species of cracids consuming soil from banks of the lower Tambopata River in southeastern Peru. Our study used observations and soil analyses from eight exposed riverbank sections to test the predictions of three models to determine why birds consume clay: mechanical aid to digestion (grit), adsorption of dietary toxins, and mineral supplementation. We found that preferred soils were deficient in particles large enough to aid in the mechanical breakdown of food and help digestion. Percent clay content and cation exchange capacity (CEC), both predicted to correlate with adsorption of toxins, did not differ between used and unused sites as had been found in a similar study. Instead, preferred soils were more saline and had higher concentrations of exchangeable sodium. This suggests that the choice of soils at our site was based primarily on sodium content. Birds may be using the heavy, plastic texture of soils rich in clays and high in exchangeable sodium as a proximal cue for soil selection. Our findings suggest that avian soil selection decisions depend on the range of available soil characteristics.RESUMENObservamos diez especies de Psittasidos, trés especies de Columbidos, y dos especies de Cracidos consumiendo suelo de los bancos del bajo Rio Tambopata en el sureste del Perú. Nuestro estudio utiliza observaciones de aves y análisis de suelos de ocho secciones expuestas de los bancos de rio para probar las predicciones de tres modelos de porque las aves consumen arcilla: ayuda mecánica para la digestión (arena triturada), adsorción de toxinas en la dieta, y suplemento mineral. Encontramos que los suelos preferidos eran deficientes en particulas lo suficientemente grandes como para ayudar en la trituración mecánica del alimento y ayudar a la digestión. El porcentaje de contenido de arcilla y la capacidad de intercambio catiónico (CIC), ambos esperados para correlacionar con la adsorción de toxinas, no varió entre sitios usados y no usados como ha sido encontrado en un estudio similar. En cambio, los suelos preferidos fueron más salinos y con mayor concentracion de sodio intercambiable. Esto sugiere que la selección de suelos en nuestro sitio de estudio está basado principalmente en el contenido de sodio. Las aves pueden estar usando las texturas densas y plásticas de los suelos ricos en arcillas con alto contenido de sodio intercambiable como una señal próxima para la selección del suelo. Nuestros resultados sugieren que las decisiones de selección de suelos por las aves depende del rango de caracteristicas de suelos disponibles.
Respiratory Ecology of Aquatic Macroinvertebratestween dissolved oxygen and invertebrate1
Authors: Chapman Lauren J. , Scnelder Kimberly R. , Apodaca Chrissy , Chapma Collin A. 
Published: March 2006

ABSTRACTHypoxia (oxygen scarcity) is widespread in tropical freshwaters, particularly in dense swamps, and may be an important factor structuring benthic macroinvertebrate communities. Macroinvertebrates show a diversity of respiratory modes ranging from atmospheric breathing to tracheal gill breathing, and these adaptations affect their ability to use hypoxic water. The objectives of this study were to (a) describe the benthic macroinvertebrate community from ten swamp and river sires in Kibale National Park, Uganda, (b) determine the degree to which dissolved oxygen explains variation in abundance of respiratory groups (taxa with a similar respiratory mode) among sites, and (c) rest for significant seasonal variation in the abundance of the numerically dominant respiratory groups. Macroinvertebrates from monthly collections over a two‐year period were identified to the lowest taxonomic level necessary to place them in functional respiratory groups. Across all sites, both the relative and absolute abundance of atmospheric breathers (e.5, pulmonate snails and nepids) and mantle/ctenidia breathers (primarily fingernail clams) were negatively correlated with dissolved oxygen, while the abundance of tracheal gill breathers (e.g. anisopterans and zygopterans) was positively correlated with dissolved oxygen. We did not detect significant seasonal trends in catch per unit effort of numerically dominant respiratory groups. Dissolved oxygen concentration was a good predictor of the abundance of some respiratory groups and may be a key factor in maintaining the structure and diversity of these assemblages.
Review of the Governing Equations, Computational Algorithms, and
Other Components of the Models-3 Community Multiscale Air Quality (CMAQ)
Modeling System
Authors: Byun Daewon , Schere Kenneth L. 
Published: March 2006

Abstract
This article describes the governing equations, computational algorithms, and other components entering into the Community Multiscale Air Quality (CMAQ) modeling system. This system has been designed to approach air quality as a whole by including state-of-the-science capabilities for modeling multiple air quality issues, including tropospheric ozone, fine particles, acid deposition, and visibility degradation. CMAQ was also designed to have multiscale capabilities so that separate models were not needed for urban and regional scale air quality modeling. By making CMAQ a modeling system that addresses multiple pollutants and different spatial scales, it has a “one-atmosphere” perspective that combines the efforts of the scientific community. To implement multiscale capabilities in CMAQ, several issues (such as scalable atmospheric dynamics and generalized coordinates), which depend on the desired model resolution, are addressed. A set of governing equations for compressible nonhydrostatic atmospheres is available to better resolve atmospheric dynamics at smaller scales. Because CMAQ is designed to handle scale-dependent meteorological formulations and a large amount of flexibility, its governing equations are expressed in a generalized coordinate system. This approach ensures consistency between CMAQ and the meteorological modeling system. The generalized coordinate system determines the necessary grid and coordinate transformations, and it can accommodate various vertical coordinates and map projections. The CMAQ modeling system simulates various chemical and physical processes that are thought to be important for understanding atmospheric trace gas transformations and distributions. The modeling system contains three types of modeling components (Models-3): a meteorological modeling system for the description of atmospheric states and motions, emission models for man-made and natural emissions that are injected into the atmosphere, and a chemistry-transport modeling system for simulation of the chemical transformation and fate. The chemical transport model includes the following process modules: horizontal advection, vertical advection, mass conservation adjustments for advection processes, horizontal diffusion, vertical diffusion, gas-phase chemical reactions and solvers, photolytic rate computation, aqueous-phase reactions and cloud mixing, aerosol dynamics, size distributions and chemistry, plume chemistry effects, and gas and aerosol deposition velocity estimation. This paper describes the Models-3 CMAQ system, its governing equations, important science algorithms, and a few application examples. This review article cites 114 references.