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Humid Forest (humid + forest)
Selected AbstractsAllometric Models for Tree Volume and Total Aboveground Biomass in a Tropical Humid Forest in Costa Rica1BIOTROPICA, Issue 1 2005Milena Segura ABSTRACT Allometric equations for the estimation of tree volume and aboveground biomass in a tropical humid forest were developed based on direct measurements of 19 individuals of seven tree species in Northern Costa Rica. The volume and the biomass of the stems represented about two-thirds of the total volume and total aboveground biomass, respectively. The average stem volume varied between 4 and 11 Mg/tree and the average total aboveground biomass ranged from 4 to 10 mg/tree. The mean specific gravity of the sampled trees was 0.62 ± 0.06 (g/cm3). The average biomass expansion factor was 1.6 ± 0.2. The best-fit equations for stem and total volume were of logarithmic form, with diameter at breast height (R2= 0.66 , 0.81) as an independent variable. The best-fit equations for total aboveground biomass that were based on combinations of diameter at breast height, and total and commercial height as independent variables had R2 values between 0.77 and 0.87. Models recommended for estimating total aboveground biomass are based on diameter at breast height, because the simplicity of these models is advantageous. This variable is easy to measure accurately in the field and is the most common variable recorded in forest inventories. Two widely used models in literature tend to underestimate aboveground biomass in large trees. In contrast, the models developed in this study accurately estimate the total aboveground biomass in these trees. RESUMEN Ecuaciones alométricas para la estimación de volumen y biomasa aérea de árboles en un bosque húmedo tropical fueron desarrollados basados en mediciones directas de 19 individuos de siete especies de árboles al norte de Costa Rica. El volumen y la biomasa del tronco representaron cerca de dos terceras partes del volumen total del árbol y de la biomasa aérea total. El volumen promedio del tronco varió entre 4 y 11 Mg/árbol y el promedio de la biomasa aérea total varió entre 4 y 10 mg/árbol. La gravedad específica promedio de los árboles muestreados fué de 0.62 ± 0.06 (g/cm3). El factor de expansión de biomasa promedio fué de 1.6 ± 0.2. Las ecuaciones de mejor ajuste para el volumen de tallo y total fueron de tipo logarítmico, con el diámetro a la altura de pecho (R2= 0.66 a 0.81) como variable independiente. Las ecuaciones de mejor ajuste para biomasa aérea total, las cuales fueron basadas en combinaciones de diámetro a la altura de pecho y altura total y comercial como variables independientes, presentaron valores de R2 entre 0.77 y 0.87. Los modelos recomendados para estimar biomasa aérea total están basados en diámetro a la altura de pecho, porque la simplicidad de estos modelos es ventajosa. Esta variable es de fácil medición en el campo y tiene mayor precision, además, es la más comúnmente registrada en inventarios forestales. Dos modelos ampliamente usados en la literature tienden a subestimar la biomasa aérea total en árboles grandes. En contraste, los modelos desarrollados en este estudio, estiman con mayor precisión la biomasa aérea total de estos árboles. [source] Population genetic structure of the malaria mosquito Anopheles arabiensis across Nigeria suggests range expansionMOLECULAR ECOLOGY, Issue 11 2001D. Y. Onyabe Abstract Ten microsatellite loci, four located within and six outside chromosome inversions, were employed to study the genetic structure of Anopheles arabiensis across the ecological zones of Nigeria (arid savannah in the north gradually turns into humid forest in the south). Regardless of location within or outside inversions, genetic variability at all loci was characterized by a reduction in both the number of alleles per locus and heterozygosity from savannah to forest. Across all loci, all but one allele in the forest also occurred in the savannah, whereas at least 78 alleles in the savannah were missing in the forest. Genetic differentiation increased with geographical distance; consequently, genetic distances between zones exceeded those within zones. The largest genetic distances were between localities at the extremes of the transect (range FST = 0.196,0.258 and RST = 0.183,0.468) and were as large as those between A. arabiensis and Anopheles gambiae s.s. Gene flow across the country was very low, so that Nm between the extremes of the transect was < 1. These data suggest that A. arabiensis has extended its range from the savannah into the forest during which it experienced a reduction in effective population size due to sequential founder effects. Gene flow post range expansion appears too restricted by geographical distance to homogenize the gene pool of A. arabiensis across Nigeria. [source] Enhanced crop productivity and compatibility through intercropping of sesame and sunflower varietiesANNALS OF APPLIED BIOLOGY, Issue 2 2009V.I.O. Olowe Abstract Field trials were conducted during 2002 and 2003 to determine the productivity and compatibility of the cropping systems obtained from intercropping varieties of sesame (E8, PBTil and 530-6-1) and sunflower (Funtua, Record and Isaanka) in the humid forest,savanna transition zone which is outside the current growing areas. Intercropping did not affect the number of branches per plant, number and weight of capsules per plant, weight of seeds per plant, 1000 seed weight or seed production efficiency (SPE) of all sesame varieties in both years, except SPE in 2003. In both years, intercropping sesame with sunflower varieties significantly reduced grain yield of PBTil and E8. However, 530-6-1 produced grain yield similar to the monocrop when intercropped with Record and Funtua in 2002 and 2003, and Record in 2003. In both years, intercropping significantly depressed the grain yield of the three sunflower varieties because of reduction in their head diameter, head weight, number and weight of seeds per head and lower number of plants per unit area relative to their monocrops. E8, 530-6-1 and PBTil intercropped with the three sunflower varieties recorded land equivalent ratio values in the range of 1.13,1.37, 1.32,1.46 and 1.22,1.35, respectively. Based on competitive ratio values, E8 demonstrated the greatest ability to compensate for intercrop competition with taller sunflower varieties. It was concluded that growers can successfully cultivate sesame (530-6-1 and PBTil) under intercropping with sunflower in the humid forest,savanna transition zone. [source] Seed Dispersal Phenology and Germination Characteristics of a Drought-Prone Vegetation in Southeastern BrazilBIOTROPICA, Issue 3 2010Maria Isabel Guedes Braz ABSTRACT Seed germination is determined by the environmental conditions typical of a habitat and also by the geographical origin of the source species pool. During the Quaternary, Brazilian Atlantic Rain Forest species expanded their distribution into the sandy coastal plains (restingas). Periods of water shortage, however, are frequent in the sandy substrate of the restinga. We investigated whether the germination characteristics of restinga species are more related to their biogeographical origin in the humid forest or to water shortage on sandy substrates. We characterized the seed dispersal phenology of a restinga community and conducted experiments to determine the water requirements for seed germination and the short-term seed dehydration sensitivity of different species. Species shed seeds throughout the year in the restinga. When subjected to ,=,0.37 MPa, seed germination percentage decreased and germination time increased in six of ten species when compared with ,=0 MPa. Most species showed high seed moisture content (MC>40 %) at seed dispersal. Seeds took 3,17 d to dehydrate when subjected to relative humidity,76 percent and only two of eight species had seeds sensitive to short-term dehydration. Thus, rather than a specific set of germination characteristics related to humid or dry habitats, we gathered evidence to show that the germination characteristics of restinga species represent a multiplicity of responses that may be found in both kinds of habitat. Abstract in Portuguese is available at http://www.blackwell-synergy.com/loi/btp [source] Allometric Models for Tree Volume and Total Aboveground Biomass in a Tropical Humid Forest in Costa Rica1BIOTROPICA, Issue 1 2005Milena Segura ABSTRACT Allometric equations for the estimation of tree volume and aboveground biomass in a tropical humid forest were developed based on direct measurements of 19 individuals of seven tree species in Northern Costa Rica. The volume and the biomass of the stems represented about two-thirds of the total volume and total aboveground biomass, respectively. The average stem volume varied between 4 and 11 Mg/tree and the average total aboveground biomass ranged from 4 to 10 mg/tree. The mean specific gravity of the sampled trees was 0.62 ± 0.06 (g/cm3). The average biomass expansion factor was 1.6 ± 0.2. The best-fit equations for stem and total volume were of logarithmic form, with diameter at breast height (R2= 0.66 , 0.81) as an independent variable. The best-fit equations for total aboveground biomass that were based on combinations of diameter at breast height, and total and commercial height as independent variables had R2 values between 0.77 and 0.87. Models recommended for estimating total aboveground biomass are based on diameter at breast height, because the simplicity of these models is advantageous. This variable is easy to measure accurately in the field and is the most common variable recorded in forest inventories. Two widely used models in literature tend to underestimate aboveground biomass in large trees. In contrast, the models developed in this study accurately estimate the total aboveground biomass in these trees. RESUMEN Ecuaciones alométricas para la estimación de volumen y biomasa aérea de árboles en un bosque húmedo tropical fueron desarrollados basados en mediciones directas de 19 individuos de siete especies de árboles al norte de Costa Rica. El volumen y la biomasa del tronco representaron cerca de dos terceras partes del volumen total del árbol y de la biomasa aérea total. El volumen promedio del tronco varió entre 4 y 11 Mg/árbol y el promedio de la biomasa aérea total varió entre 4 y 10 mg/árbol. La gravedad específica promedio de los árboles muestreados fué de 0.62 ± 0.06 (g/cm3). El factor de expansión de biomasa promedio fué de 1.6 ± 0.2. Las ecuaciones de mejor ajuste para el volumen de tallo y total fueron de tipo logarítmico, con el diámetro a la altura de pecho (R2= 0.66 a 0.81) como variable independiente. Las ecuaciones de mejor ajuste para biomasa aérea total, las cuales fueron basadas en combinaciones de diámetro a la altura de pecho y altura total y comercial como variables independientes, presentaron valores de R2 entre 0.77 y 0.87. Los modelos recomendados para estimar biomasa aérea total están basados en diámetro a la altura de pecho, porque la simplicidad de estos modelos es ventajosa. Esta variable es de fácil medición en el campo y tiene mayor precision, además, es la más comúnmente registrada en inventarios forestales. Dos modelos ampliamente usados en la literature tienden a subestimar la biomasa aérea total en árboles grandes. En contraste, los modelos desarrollados en este estudio, estiman con mayor precisión la biomasa aérea total de estos árboles. [source] A new species of piha (Cotingidae: Lipaugus) from the Cordillera Central of ColombiaIBIS, Issue 4 2001ANDRÉS M. CUERVO The Chestnut-capped Piha Lipaugus weberi sp. nov., is described from sub-Andean forest on the northern slope of the Central Cordillera of the Colombia Andes. The new species appears most closely related to Lipaugus fuscocinereus of the Northern Andes including the Central Cordillera, but is much smaller, with a distinctive chestnut-brown crown, yellow orbital ring, two modified primaries in the male, an overall darker grey coloration and unique vocalizations. It appears to be restricted to a narrow belt of premontane very humid forests (1500,1820 m asl) where it is fairly common. The restricted range and specific ecological requirements of Lipaugus weberi make the species of great conservation concern as the Central Cordillera has been severely deforested and remaining forests are highly fragmented. We present notes on the behaviour, ecology and conservation of this new species. Se describe Lipaugus weberi sp. nov, de bosque subandino de la vertiente norte de la Cordillera Central de los Andes de Colombia. La nueva especie parece estar bastante relacionada con Lipaugus fuscocinereus de los Andes septentrionales incluyendo la Cordillera Central, pero es mucho más pequeña, presenta una distintiva gorra castaño opaco, anillo ocular amarillo, dos remeras primarias modificadas, la coloración gris más oscura y vocalizaciones ünicas. Esta especie se restringe a una franja angosta de bosque muy hümedo premontano (1500,1820 msnm), donde es relativamente comün. El rango restringido y los requerimientos ecológicos especificos de Lipaugus weberi hacen que esta especie sea de gran relevancia para la conservación, más aün debido al estado de deforestación severa de la Cordillera Central, en la cual los bosques remanentes son muy fragmentados. Presentamos anotaciones sobre la ecologia, el comportamiento y la conservación de esta nueva especie. [source] Phylogenetic relationships, diversification and biogeography in Neotropical Brotogeris parakeetsJOURNAL OF BIOGEOGRAPHY, Issue 9 2009Camila C. Ribas Abstract Aim, We present a molecular phylogenetic analysis of Brotogeris (Psittacidae) using several distinct and complementary approaches: we test the monophyly of the genus, delineate the basal taxa within it, uncover their phylogenetic relationships, and finally, based on these results, we perform temporal and spatial comparative analyses to help elucidate the historical biogeography of the Neotropical region. Location, Neotropical lowlands, including dry and humid forests. Methods, Phylogenetic relationships within Brotogeris were investigated using the complete sequences of the mitochondrial genes cyt b and ND2, and partial sequences of the nuclear intron 7 of the gene for Beta Fibrinogen for all eight species and 12 of the 17 taxa recognized within the genus (total of 63 individuals). In order to delinetae the basal taxa within the genus we used both molecular and plumage variation, the latter being based on the examination of 597 skin specimens. Dates of divergence and confidence intervals were estimated using penalized likelihood. Spatial and temporal comparative analyses were performed including several closely related parrot genera. Results,Brotogeris was found to be a monophyletic genus, sister to Myiopsitta. The phylogenetic analyses recovered eight well-supported clades representing the recognized biological species. Although some described subspecies are diagnosably distinct based on morphology, there was generally little intraspecific mtDNA variation. The Amazonian species had different phylogenetic affinities and did not group in a monophyletic clade. Brotogeris diversification took place during the last 6 Myr, the same time-frame as previously found for Pionus and Pyrilia. Main conclusions, The biogeographical history of Brotogeris implies a dynamic history for South American biomes since the Pliocene. It corroborates the idea that the geological evolution of Amazonia has been important in shaping its biodiversity, argues against the idea that the region has been environmentally stable during the Quaternary, and suggests dynamic interactions between wet and dry forest habitats in South America, with representatives of the Amazonian biota having several independent close relationships with taxa endemic to other biomes. [source] Sampling methods for phlebotomine sandfliesMEDICAL AND VETERINARY ENTOMOLOGY, Issue 2 2000B. Alexander Summary A review is presented of methods for sampling phlebotomine sandflies (Diptera: Psychodidae). Among ,500 species of Phlebotominae so far described, mostly in the New World genus Lutzomyia and the Old World genus Phlebotomus, about 10% are known vectors of Leishmania parasites or other pathogens. Despite being small and fragile, sandflies have a wide geographical range with species occupying a considerable diversity of ecotopes and habitats, from deserts to humid forests, so that suitable methods for collecting them are influenced by environmental conditions where they are sought. Because immature phlebotomines occupy obscure terrestrial habitats, it is difficult to find their breeding sites. Therefore, most trapping methods and sampling procedures focus on sandfly adults, whether resting or active. The diurnal resting sites of adult sandflies include tree holes, buttress roots, rock crevices, houses, animal shelters and burrows, from which they may be aspirated directly or trapped after being disturbed. Sandflies can be collected during their periods of activity by interception traps, or by using attractants such as bait animals, CO2 or light. The method of trapping used should: (a) be suited to the habitat and area to be surveyed, (b) take into account the segment of the sandfly population to be sampled (species, sex and reproduction condition) and (c) yield specimens of appropriate condition for the study objectives (e.g. identification of species present, population genetics or vector implication). Methods for preservation and transportation of sandflies to the laboratory also depend on the objectives of a particular study and are described accordingly. [source] | ||||||||||