Community structure of raptors in the páramo landscape of the Ecuadorian Andes

Introduction: Habitat alterations result in biodiversity loss, particularly in regions with high levels of diversity and endemism. Raptors are an essential part of the functionality and stability of ecosystems and indicators of habitat quality. In the paramo grassland ecosystems in the high Andes of Northern South America, raptors contain a high concentration of threatened species. Objective: To describe the raptor community structure and determine the species associations. Methods: We made monthly raptor counts in eight transects from October 2021 to September 2022 and used a principal component analysis to determine species associations. Results: We identified 149 individuals (seven species, three families) in two communities: abundant (Carunculated Caracara, Variable Hawk, Andean Condor and Turkey Vulture; PCI = 47 %), and scarce (Cinereous Harrier, Peregrine Falcon and Aplomado Falco; PCII = 27 %). Conclusion: We provide a valid description and understanding of raptor community structure, identifying two communities and the dynamics between them. The first is characterized by an increased abundance of generalist and regionally common species, when the abundance of these species decreases, the second community is defined, characterized by an increase in the abundance of specialist and rare species at the local scale.

Introducción: Las alteraciones del hábitat provocan la pérdida de biodiversidad, especialmente en regiones con altos niveles de diversidad y endemismo. Las aves rapaces son una parte esencial de la funcionalidad y estabilidad de los ecosistemas, y son indicadores de la calidad del hábitat. En los ecosistemas de páramo en los Andes del norte de Sudamérica, hay una concentración de especies rapaces amenazadas. Objetivo: Describir la estructura de la comunidad de aves rapaces y determinar las asociaciones entre las especies. Métodos: Hicimos conteos mensuales de rapaces en ocho transectos, de octubre 2021 a setiembre 2022 y usamos un análisis de componentes principales para determinar las asociaciones entre especies. Resultados: Identificamos 149 individuos (siete especies, tres familias) en dos comunidades: abundantes (e.g., Caracara Curiquingue, Gavilán Variable, Cóndor Andino y Gallinazo Cabecirrojo; PCI = 47 %), y poco abundantes (e.g., Caracara Curiquingue, Gavilán Variable, Cóndor Andino y Gallinazo Cabecirrojo; PCII = 27 %). Conclusiones: Nuestro enfoque proporciona una descripción y comprensión válida de la estructura de la comunidad de rapaces. Identificamos dos comunidades y la dinámica entre ellas. La primera se caracteriza por una mayor abundancia de especies generalistas y regionalmente comunes, cuando la abundancia de estas especies disminuye, se define la segunda comunidad, caracterizada por un aumento de la abundancia de especies especialistas y raras a escala local.

Effects of volatile fatty acids in biohydrogen effluent on biohythane production from palm oil mill effluent under thermophilic condition

Background: Biohydrogen effluent contains a high concentration of volatile fatty acid (VFA) mainly as butyric, acetic, lactic and propionic acids. The presence of various VFAs (mixture VFAs) and their cooperative effects on two-stage biohythane production need to be further studied. The effect of VFA concentrations in biohydrogen effluent of palm oil mill effluent (POME) on methane yield in methane stage of biohythane production was investigated. Results: The methane yield obtained in low VFA loading (0.9 and 1.8 g/L) was 15­20% times greater than that of high VFA loading (3.6 and 4.7 g/L). Butyric acid at high concentrations (8 g/L) has the individual significantly negative effect the methane production process (P b 0.05). Lactic, acetic and butyric acid mixed with propionic acid at a concentration higher than 0.5 g/L has an interaction significantly negative effect on the methanogenesis process (P b 0.05). Inhibition condition had a negative effect on both bacteria and archaea with inhibited on Geobacillus sp., Thermoanaerobacterium thermosaccharolyticum, Methanoculleus thermophilus and Methanothermobacter delfuvii resulting in low methane yield. Conclusion: Preventing the high concentration of butyric acid, and propionic acid in the hydrogenic effluent could enhance methane production in two-stage anaerobic digestion for biohythane production.

An enhanced calibration of a recently released megatree for the analysis of phylogenetic diversity / Calibração aperfeiçoada de uma megatree lançada recentemente para a análise da diversidade filogenética

Abstract Dated or calibrated phylogenetic trees, in which branch lengths correspond to evolutionary divergence times between nodes, are important requirements for computing measures of phylogenetic diversity or phylogenetic community structure. The increasing knowledge about the diversification and evolutionary divergence times of vascular plants requires a revision of the age estimates used for the calibration of phylogenetic trees by the bladj algorithm of the Phylocom 4.2 package. Comparing the recently released megatree R20120829.new with two calibrated vascular plant phylogenies provided in the literature, we found 242 corresponding nodes. We modified the megatree (R20120829mod.new), inserting names for all corresponding nodes. Furthermore, we provide files containing age estimates from both sources for the updated calibration of R20120829mod.new. Applying these files consistently in analyses of phylogenetic community structure or diversity serves to avoid erroneous measures and ecological misinterpretation.

Resumo Árvores filogenéticas datadas, ou calibradas, em que os comprimentos dos ramos correspondem ao tempo evolutivo de divergência entre os nós, são importantes requisitos para calcular medidas de diversidade filogenética ou de estrutura filogenética de comunidades. O conhecimento crescente sobre a diversificação e sobre o tempo de divergência evolutiva das plantas vasculares fez necessária uma revisão das estimativas de idades dos nós que são utilizadas para a calibração de árvores filogenéticas por meio do algoritmo bladj do pacote Phylocom 4.2. Comparando a mega-árvore R20120829.new, recentemente publicada, e outras duas filogenias calibradas de plantas vasculares, encontramos 242 nós correspondentes. Modificamos esta mega-árvore (R20120829mod.new), inserindo todos os nomes dos nós correspondentes. Além disso, providenciamos dois arquivos com todas as estimativas das idades para uma calibração mais atualizada. Utilizando esses arquivos de maneira consistente nas análises de diversidade ou de estrutura filogenética de comunidades, evita-se incorreções nas datações e imprecisões na interpretação de informações ecológicas.

Space remote sensing for spatial vegetation characterization.

The study area, Madhav National Park (MP) represents northern tropical dry deciduous forest. The national park, due to its unique location (nearest to township), is under tremendous biotic pressure. In order to understand vegetation structure and dynamics, vegetation mapping at community level was considered important. Prolonged leafless period and background reflection due to open canopy poses challenge in interpretation of satellite data. The vegetation of Madhav National Park was mapped using Landsat TM data. The ground data collected from sample points were subjected to TWINSPAN analysis to cluster sample point data into six communities. The vegetation classification obtained by interpretation (visual and digital) of remote sensing data and TWINSPAN were compared to validate the vegetation classification at community level. The phytosociological data collected from sample points were analysed to characterize communities. The results indicate that structural variations in the communities modulate spectral signatures of vegetation and form basis to describe community structure subjectively and at spatial level.

T_RFLP Technique and Its Application on Community Analysis of Nitrifying Bacteria / 微生物学通报

Terminal restriction fragment length polymorphism (T_RFLP) analysis is a culture- independent approach for analyzing microbial community in environment. It bases on PCR technology, and its process includes DNA extraction of environmental samples, amplification of genes encoding the 16S rRNA, 18S rRNA or enzymes with fluorescently labeled primers, the restriction enzyme digestion of PCR products, cap- illary electrophoresis and the analysis of T_RFLP profile. It has been proved to be powerful applied on mi- crobial community in environment since developed in 1997. Currently, T_RFLP rarely applied in China, and it has no applications on microbial community analysis of nitrifying bacteria. In this article, the fundamental principle of this technique and the recent applications of T_RFLP on microbial community are summarized; in addition, it illustrates the confinements of conventional culture-dependent of nitrifying bacteria and the foreground of T_RFLP applying on microbial community structure analysis of nitrifying bacteria.