bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Macrofauna of Water‐filled Tree Holes on Barro Colorado Island, Panama1
Authors: Yanovlak Stephen P. 
Published: March 2006

ABSTRACTThe fauna of water‐filled tree holes in Neotropical forests is not well documented. Cumulatively, 54 macroinvertebrate and 5 vertebrate taxa were found in artificial and natural tree holes censused over four wet seasons on Barro Colorado Island, Panama. Most of the species were in the insect order Diptera, occurred as aquatic larvae in tree holes, and were detritivore/omnivores. Half (49%) of the collected species are considered specialists in this and similar container habitats, and three invertebrate taxa were previously unknown from tree holes. Successional patterns were weak in tree holes, but some taxa predictably colonized holes shortly after they were filled. The mosquito Culex urichii was more common and abundant in artificial than in natural tree holes; occurrence frequencies and densities of most other taxa were similar between hole types.RESUMESLa macrofauna de reservorios de agua en los huecos de los árboles de bosques neotropicales no ha sido bien documentada. En total, 54 grupos de macroinvertebrados y 5 grupos de vertebrados fueron encontrados en huecos artificiales y naturales examinados durante cuatro estaciones lluviosas en la Isla Barro Colorado, Panamá. De las especies encontradas, la mayoría pertenecen al orden Diptera. También, la mayoría ocurren como larvas acuáticas y son detrívoros/omnívoros. Cerca de la mitad (49%) de las especies son consideradas como especialistas en este tipo de háabitat y reservorios similares, y tres grupos de invertebrados no han sido reportados en los huecos de los árboles. No existen patrones de sucesión fuertes en los huecos de los árboles, pero algunos grupos colonizan los reservorios poco tiempo después que están llenos. El mosquito Culex urichii file la especie más común y más abundance en los huecos artificiales que en los huecos naturales; las frequencias y densidades de otras especies fueron similares entre los dos tipos de huecos.
Terrestrial Small Mammal Richness and Habitat Associations in an Amazon Forest–Cerrado Contact Zone1
Authors: Lacher Thomas E. , Alho Cleber J. R. 
Published: March 2006

ABSTRACTThe Amazon Forest and the Cerrado of central Brazil share an extensive zone of integration. Each of these major ecosystems remains poorly studied; however, the composition of communities at the contact zone is even less well described. Small mammals were sampled during a ten–week period in a zone of contact between Amazonian forest and Cerrado. The vegetation in the area was a complex mixture of tropical and semi–deciduous forest, and grassland and savanna woodland formations. Mammals were marked and recaptured on 0.25– to 0.5–km transects and vouchers were collected. A total of 19 species was caught (13 rodents and 6 marsupials) in 4621 trap nights. Transitions from one vegetation type to another were abrupt with ecotones frequently < 5 m in width. The highest a–diversity was 7 species in cerrado. Ten of the 19 species were restricted to one habitat and 6 were restricted to two habitats. Three generalist grassland species occurred in more than two habitats, all variations of savanna. These data support other research indicating high habitat specificity of vertebrates and plants in the Brazilian savannas. The diversity of habitats within reserves in tropical grasslands must be given consideration in the design of protected areas in order to maximize the conservation of mammalian biodiversity.RESUMESA floresta Amazônica e o Cerrado do Brasil Central compartilham uma zona extensa de integração. Estes ecossistemas são pouco estudados, e a composição das comunidades que ocorrem na zona de contato é ainda menos conhecida. Pequenos mamiferos foram capturados durance um período de 10 semanas em uma zona de contato entre a floresta Amazônica e o Cerrado. A vegetação desta área é um complexo de florestas semidecíduas e tropicais, campos e cerrados. Mamiferos foram capturados e marcados em transetos variando de 250 a 500 m; uma coleção de referênda também foi feita. Capturamos um total de 19 espécies (13 roedores e 6 marsupiais) em 4621 noitesarmadilhas. As transições entre tipos de vegetação foram abruptas com ecótonos frequentemente menores que 5 m de largura. O cerrado teve a a‐diversidade mais alta: sete espécies. Dez das 19 espécies estavam restritas a um habitat e seis a dois habitats. Três espécies generalistas de savana ocorreram em mais de dois habitats, mas sempre em algum tipo de campo ou cerrado aberto. Estes dados corroboram com outras pesquisas indicando um alto nivel de especificidade de habitat para vertebrados e plantas no Cerrado. Consequentemente, para melhor preservar a diversidade de mamíferos no Brasil Central deve‐se dar mais atenção à diversidade de habitats em áreas de proteção no Cerrado.
Dietary Choices of the Pouched Mouse (Saccostomus mearnsi) in Central Kenya1
Authors: Metz M. R. , Keesing F. 
Published: March 2006

ABSTRACTAlthough there is growing recognition of the importance of small mammals in savanna ecosystems of east Africa, the ecology and behavior of these organisms are not well known. We conducted studies on the dietary preferences of one rodent, the pouched mouse (<Saccostomus mearnsi), which is the dominant small mammal in a widespread habitat in central Kenya. To establish the food preferences of this species, we: (1) conducted cafeteria trials in the laboratory whereby individual mice were offered seeds and a selection of herbaceous vegetation from the habitat; (2) surveyed the habitat for piles of vegetation clipped by these mice and identified these clippings to species; and (3) estimated the abundance of plant species in the habitat to determine if the mice were clipping species in proportion to their availability. Our results indicated that 5. mearnsi prefers green vegetation to seeds, at least during wet seasons, and that it has a strong preference for forbs. In cafeteria trials, 5. mearnsi chose 93 percent green vegetation and only 7 percent seeds. The forb Commelina africana was highly preferred over other food items offered. In the habitat, two forbs, C. africana and Monsonia angustifolia, constituted > 40 percent of the piles of clippings, although these two species together made up < 4 percent of the available vegetation. Grasses also were clipped frequently, although in lower proportions than their availability in the habitat. The herbivorous habits of 5. mearnsi establish the potential of this species to compete for resources with ungulates, which are abundant in this habitat.
Vegetative Identification of Tropical Woody Plants: State of the Art and Annotated Bibliography1
Authors: Rejmánek Marcel , Brewer Steven W. 
Published: March 2006

ABSTRACTThis annotated bibliography is provided in order to assess the achievements and gaps in the literature on vegetative identification of woody plants in the tropics. The bibliography includes 258 references divided into general references (48), pantropical and multi‐continental keys (4), Africa (46), Asia (53), Australia and New Guinea (21), and the Neotropics (86). Vegetative keys are not easy shortcuts to the identification of woody tropical plants to species. Identification of sterile material requires as much, if not more, training as that required for using keys that emphasize floral and fruit characters. Nevertheless, the literature surveyed in this bibliography may be helpful to biologists seeking references for the geographic region in which they work, models for the construction of vegetative keys and field guides, and/or the types of characters that should be observed in the field.
Nitrogen and Phosphorus Release from Decomposing Leaves under Sub‐Humid Tropical Conditions1
Authors: Kwabiah A. B. , Stoskopf N. C. , Voroney R. P. , Palm C. A. 
Published: March 2006

ABSTRACTFor many soils of the tropics, inputs of organic materials are essential to sustain soil fertility and crop production. Research in the quality of organic inputs, a key factor controlling rates of decomposition and nutrient release, continues to guide selection and use of organic materials as nutrient sources. The relationship between decomposition patterns and the quality parameters of the fresh leaves of six agroforestry species:Sesbania sesban, Croton megalocarpus, Calliandra calothyrsus, Tithonia diversifolia, Lantana camara, andSenna spectabilis, was investigated in a litterbag study over a period of 77 days in the highlands of western Kenya. The litterbags were buried 1 cm below the soil surface and covered with soil ofca1 cm thickness. Percent leaf mass and total N and P that remained with time strongly correlated with total P and C/P ratio (R2= 0.60‐0.90) during the first 35 days of study; but afterwards, correlation was stronger with the initial soluble polyphenolics (Pp)/P ratio (R2=0.69‐0.92) than with total P and C/P ratio. Loss of leaf mass and release of N and P followed the exponential function, yt= y0* e‐kt, from which the specific decay rate constants (k) were calculated for loss of leaf mass (kB) and release of N (kN) and P (Kp). Among the plant species, thekvalues were lowest inCalliandrawithkB=0.012/d,kN=0.017/d andkp= 0.044/d.Lantanahad the highest K values withkg=0.067/d andkp=0.119/d, but the highestkNvalue of 0.109/d occurred inTithonia.ThekBvalues for all organic materials were lower than their correspondingkNandkpvalues, suggesting that leaching of N and P from litters may have augmented the microbial mineralization of N and P. There was a strong correlation between thekB, kN, andkpvalues and total P (r = 0.82‐0.96;P0.01), but not total N, lignin (LIG), or Pp. Rates of N and P release followed the general trend:Tithonia > Senna > Lantana > Sesbania > Croton > Calliandra.The results indicated that, among the quality parameters studied, total P is the most important factor controlling rate of decomposition and N and P release from organic inputs in the area of study.
Brazilian Päramos. III. Patterns and Rates of Postfire Regeneration in the Campos de Altitude1
Authors: Safford Hugh DeForest 
Published: March 2006

ABSTRACTPostfire vegetation development was studied at two recent mountaintop burns in the Serra do Caparaó, Espírito Santo/ Minas Gerais, and the Serra dos órgãos, Rio de Janeiro, Brazil. Both fires occurred within the páramo‐like “campos de altitude”, a system of orographic grass‐ and scrublands restricted to the highest peaks of southeast Brazil. Data collected included pre‐ and postfire heights and densities of shrubs and trees, and cover of all taxa. Slopes of different aspect and altitude were sampled at each site to evaluate the effects of varying physical environment on regeneration. Rapid vegetative regeneration was common among shrubs and bamboo, with most taxa surviving fire. Regeneration and postfire colonization rates varied among species, and appeared to depend both on physical variables associated with different slopes, aspects and altitudes, and biotic variables. Most plant species in the campos de altitude show some form of evolutionary adaptation to fire. The distribution of species and plant populations across the landscapes of the campos de altitude appears to be largely the result of fire and its interactions with the biota, local topography, and climate. Results suggest that fire is an integral part of the ecology in these humid, seasonally dry ecosystems. Successful management of these unique and highly threatened systems requires a detailed understanding of the fire regime and its role in structuring biotic communities.RESUMESA regeneração da vegetação pós‐incêndio foi estudada em dois locais recentemente queimados nos campos de altitude da Serra do Caparaó, Espírito Santo/Minas Gerais e da Serra dos órgãos, Rio de Janeiro, Brasil. Foram amostradas as alturas e a densidade de plantas lenhosas pré‐ e pós‐incêndio, tal como a cobertura vegetal do estrato herbáceo. Em cada local foram amostradas encostas com orientações diferentes e também diferentes altitudes para avaliar os efeitos de variações do ambiente fisico na regeneração. A regeração da vegetação, especialmente de arbustos e bambu, se mostrou rápida, com a maioria das espécies sobrevivendo ao incêndio. As taxas de regeneração e colonização pósincéndio variaram entre espécies e entre locais e aparentemente dependem tanto de variáveis fisicas ligadas a rumos, declividades e altitudes diferentes, como também de variáveis bióticas. A maioria das espécies de plantas nos campos de altitude a prestam adaptações ao fogo. A distribuição das espécies e populações de plantas na paisagem dos campos de altitude parece ser o resultado da ação do fogo e de sua interação com a biota, a topografia local e o clima. Os resultados sugerem que fogo é um fator fundamental da ecologia desses ecosistemas úmidos porém sazonalmente secos. é impossível estabelecer um manejo adequado desses ecossistemas únicos e ameaçãdos sem uma compreensão detalhada do regime de fogo e do papel que incéndios desempenham na estructuração de comunidades bióticas.
Seedling Mortality in Hawaiian Rain Forest: The Role of Small‐Scale Physical Disturbance1
Authors: Drake Donald R. , Pratt Linda W. 
Published: March 2006

ABSTRACTMost montane rain forests on the island of Hawaii consist of a closed canopy formed by Cibotium spp. tree ferns beneath an open canopy of emergent Metrosideros polymorpha trees. We used artificial seedlings to assess the extent to which physical disturbance caused by the senescing fronds of tree ferns and the activities of feral pigs might limit tree regeneration. Artificial seedlings were established terrestrially (N= 300) or epiphytically (N = 300) on tree fern stems. Half of the seedlings on each substrate were in an exclosure lacking feral pigs and half were in forest with pigs present. After one year, the percentage of seedlings damaged was significantly greater among terrestrial seedlings (25.7%) than epiphytic seedlings (11.3%). Significantly more terrestrial seedlings were damaged in the presence of pigs (31.3%) than in the absence of pigs (20.0%). Senescing fronds of tree ferns were responsible for 60.3 percent of the damaged seedlings. Physical disturbance is potentially a major cause of seedling mortality and may reduce the expected half‐life of a seedling cohort to less than two years.
Deforestation in Costa Rica: A Quantitative Analysis Using Remote Sensing Imagery1
Authors: Sánchez‐Azofeifa G. Arturo , Harriss Robert C. , Skole David L. 
Published: March 2006

ABSTRACTAccurate estimates of forest cover and forest fragmentation are critical for developing countries such as Costa Rica, which holds four to five percent of the world's plant and bird species. We estimated forest cover for Costa Rica using Landsat 5 Thematic Mapper satellite scenes acquired between 1986 and 1991. In 1991, 29 percent (ca 14,000 km2) of the land cover of Costa Rica was closed forest cover; of that forested area, ca 30 percent is protected by national conservation policies. Forest loss in a study area representing ca 50 percent of Costa Rica's territory during a five‐year period (1986–1991) was 2250 km2, and the estimated deforestation rate was ca 450 km2/yr, or ca 4.2 percent/yr, of remaining forest cover. Forests are almost completely eliminated from the Tropical Moist Forest and Premontane Moist Forest life zones, and the level of fragmentation of remaining forests may be more advanced than previously thought.RESUMESLa obtención de estimaciones precisas de la cobertura forestal y su nivel de fragmentación es crítica para la conservatión de la biodiversidad. Costa Rica contiene en su territorio nacional entre el cuatro y cinco por ciento de todas las especies de plantas y aves del mundo. Este estudio provee una estimatión precisa de la cobertura nacional forestal del país y su distribution a nivel ecológico basada en imágenes de satélite adquiridas entre 1986 y 1991 por el Trazador Temático Landsat 5. Para 1991, el país tenía una cobertura forestal de bosque perennifolio del 29 por ciento (ca 14,000 km2); el 71 por ciento de este bosque carecía de protectión mientras que el 29 por ciento restante está protegido por el Sistema Nacional de áreas de Conservación. La pérdida total de bosque en el area de estudio, durante un periodo de cinco años (1986‐1991) y la cual representa ca 50 por ciento del territorio nacional, rue de 2250 km2. La tasa de deforestatión estimada es de ca 450 km2 por año, o ca 4.2 por ciento anual. El proceso de deforestatión tropical ha eliminado casi completamente los bosques húmedo tropical y húmedo premontano del país. Los resultados de este trabajo sugieren que el nivel de fragmentación de los bosques costarricenses puede ser mas grande de lo que se habiá pensado.
Age of A2 Horizon Charcoal and Forest Structure near Porto Trombetas, Pará, Brazil1
Authors: Francis John K. , Knowles Oliver Henry 
Published: March 2006

ABSTRACTTo study the structure and composition of old‐growth forest in the Saracá‐Taquera National Forest near Porto Trombetas, Brazil, we established 36 0.25 ha plots and described the vegetation. We collected charcoal from the A2 soil horizon of each plot for radiocarbon dating. Although fires have been very rare in this forest during historic times, the presence of charcoal in these soils indicates fire at some earlier period. The ages (conventional radiocarbon age adjusted to 1997) of the charcoal ranged from 177 to 1547 years. These ages, however, did not correlate significantly with any of several measures of biodiversity or stand characteristics. The relative uniformity of the current old‐growth forest indicates that either the prehistoric fires were of such low intensity that they had little long‐term effect on the vegetation or that the present stands have progressed to near steady state.
Morphology and Biology of Napoleonaea vogelii (Lecythidaceae) Flowers in Relation to the Natural History of Insect Visitors1
Authors: Frame Dawn , Durou Sébastien 
Published: March 2006

ABSTRACTIn Gabon, we investigated the floral morphology and biology of Napoleonaea vogelii (Lecythidaceae), a cauliflorous understory tree of lowland humid rain forest, and made observations on the behavior of insect visitors. The major insects visiting flowers were: a thrips (Ceratothripoides brunneus), a small moth (Glyphipterix sp.), four species of leaf beetles (Gabonia colae, Gabonia sp. undescribed, Macrocoma sp., and Monolepta sp.), three species of weevils (Endaeus sp. 1–3), and two species of ants (Technomyrmex sp. and Monomorium sp.). In TV. vogelii, the flower is quite complex, and we propose a floral morphological definition for complexity. Insect visitors are spatially segregated on the flower. The evolution of the morphology and biology of the flower of N. vogelii is influenced by insect visitors, both pollinating and non–pollinating. The thrips are the likely pollinators of the flower.RESUMESAu Gabon, nous avons étudié Napoleonaea vogelii (Lecythidaceae), un arbre cauliflore du sous bois de la for○t humide de plaine. Nos recherches ont porté sur la morphologic et la biologic florales. Nous avons observé le comportement des insectes visiteurs, dont les principals espèces sont: un thysanoptère (Ceratothripoides brunneus), un lépidoptère (Glyphipterix sp.), quatre espèces de coléoptères chrysomélides (Gabonia colae, Gabonia sp. non décrite, Macrocoma sp., et Monolepta sp.), trois espèces de coléoptères curculionides (Endaeus sp. 1‐3), et deux espèces de fourmis (Technomyrmex sp. et Monomorium sp.). La fleur de N. vogelii est trés complexe et nous proposons une définition mor‐phologique de la complexityé florale. II existe une ségrégation spatiale des insectes visiteurs dans la fleur. L'évolution de la morphologic et de la biologic de la fleur de N. vogelii est liée aux insectes visiteurs, aussi bien les pollinisateurs que les autres. II est fort probable que les thysanoptères pollinisent la fleur.
Responses of Aquatic Macrophytes to Disturbance by Flash Floods in a Brazilian Semiarid Intermittent Stream1
Authors: Maltchik Leonardo , Pedro Fabio 
Published: March 2006

ABSTRACTResistance and resilience of Najas marina to disturbance by flash floods were studied in a permanent fluvial pool of a Brazilian semiarid intermittent stream. A total of 21 macrophyte samples was collected in the high‐rainfall season during two annual cycles (1996–1997). Decreases in macrophyte biomass were positively correlated with flood magnitude (Pearson, P = 0.047), varying from 25 to 53 percent when discharges were lower than or equal to 0.5 m3/ sec and between 70 and 100 percent when discharges were higher than 1.0 m‐3/sec. Macrophyte resilience was greater after floods of low magnitude. After floods of 0.5 m‐3/sec, three weeks were necessary to re‐establish 88 percent of biomass lost, and after a flood of 1.4 m‐Vsec, six months were needed to initiate A, marina regrowth. This population of N. marina in Avelós stream has higher stability in response to small disturbances, but as expected, its resistance and resilience decreases with larger disturbances. In general, the high resistance and resilience of N. marina m response to small disturbances have been observed in intermittent tropical streams. The absence of large floods during the study period and the low variability of water temperature in this tropical region may have influenced these results.RESUMESA influencia de cheias rápidas na resistência e na resistência de Najas marina foram estudadas em uma poça fluvial permanente de um riacho efêmero do Semi‐árido Brasileiro. Vinte e uma coletas de macrófitas aquáticas foram realizadas durante o período de chuvas de dois ciclos anuais (1996 e 1997). A variaçäo da biomassa de macrófitas aquáticas estava diretamente correlacionada com a magnitude da cheia (Pearson, P=0.047), variando entre 25 e 53 por cento quando as vazöes eram inferiores ou iguais à 0.5 m3‐Vsec e entre 70 e 100 por cento quando as vazöes eram superiores à 1.0 m3/sec. A resiliência de macrófitas era maior após às cheias de baixa magnitude. Após a cheia de 0.5 m3‐Vsec, foram necessários seis meses para restabelecer 88 por cento da biomassa perdida, e após a cheia de 1.4 m3/ sec, foram necessáries seis meses para iniciar a resiliência de Najas marina. Esta populaçäo de N. marina do riacho Avelós apresentou maior estabilidade frente ás perturbaçöes hidrológicas de baixa magnitude, mas a resistêncía e a resiliéncia diminuíam à medida que a magnitude da perturbaçao aumentava. A alta resístência e resiliência de N marina frente às perturbaçöes hidrológicas de baixa magnitude, geralmente tem sido observadas em riachos intermi‐tentes tropicais. A ausência de grandes cheias durante o periodo estudado e a pequena amplitude térmica da água superficial desta regiäo tropical podem ter favorecido estes resultados.