Tree structure and diversity of a Humid Mountain Forest in the protected natural area La Martinica, Veracruz, Mexico / Estructura y diversidad arbórea de un bosque húmedo de montaña en el Área Natural Protegida La Martinica, Veracruz, México

Abstract Introduction: The Humid Mountain Forest (HMF) has the highest number of plants per unit of surface, whose vegetation grows under heterogeneous environmental conditions and possess a high floristic variation. HMF conservation is important due to the biodiversity it harbors and the environmental services it provides. Objective: This work evaluated the effect of the terrain aspect and density of the forest canopy on the structure and tree diversity in La Martinica Protected Natural Area, Mexico. Methods: Stratified sampling was performed in four terrain aspects and two canopy density conditions. Twenty five sampling units of 20 x 25 m were considered, in which the normal diameter (ND), total height and the largest and smallest diameters of the crown of the individuals with a ND ≥ 10 cm were registered. The diversity was estimated by rarefaction curves and the structure was analyzed through the importance value index (IVI) and the forest value index (FVI). Results: 37 species belonging to 30 genera and 24 families were recorded. Greater diversity was observed in the north terrain aspect and in the closed canopy. Tree species with the highest structural values were different between terrain aspect and canopy types; Carpinus tropicalis presented the highest values in the zenithal terrain aspect, Lippia myriocephala in the east and south terrain aspect, and Liquidambar styraciflua in the north. In both canopy types Lippia myriocephala obtained the highest IVI values and FVI in the open canopy; Carpinus tropicalis reached a higher FVI in the closed canopy. Conclusions: Tree structure was different in the four terrain aspects and two canopy conditions studied. The greatest difference in species composition and diversity was observed between the north and east terrain aspects; the north presented the highest richness values, frequent and dominant species.

Resumen Introducción: El Bosque Húmedo de Montaña (BHM) posee el mayor número de especies vegetales por unidad de superficie, cuya vegetación se desarrolla en condiciones ambientales muy heterogéneas y presenta una alta variación florística. La conservación del BHM es importante debido a la biodiversidad que alberga y los servicios ambientales que proporciona. Objetivo: Este trabajo evaluó el efecto de la orientación del terreno y la densidad del dosel del bosque sobre la estructura y diversidad arbórea en el Área Natural Protegida La Martinica, México. Métodos: Se efectuó un muestreo estratificado en cuatro orientaciones del terreno y dos condiciones de densidad del dosel; se consideraron 25 unidades de muestreo de 20 x 25 m, en las que se registró: el diámetro normal (DN), la altura total y los diámetros mayor y menor de la copa de los individuos con un DN ≥10 cm. La diversidad se estimó por medio de curvas de rarefacción y la estructura se analizó con el índice de valor de importancia (IVI) y el índice de valor forestal (IVF). Resultados: Se registraron 37 especies pertenecientes a 30 géneros y 24 familias. Se observó una mayor diversidad en la orientación norte y en el dosel cerrado. Las especies arbóreas con valores estructurales más altos fueron diferentes entre orientaciones y tipos de dosel; Carpinus tropicalis presentó los valores más elevados en la orientación cenital, Lippia myriocephala en las orientaciones este y sur, y Liquidambar styraciflua en la norte. En ambos tipos de dosel Lippia myriocephala obtuvo los valores más altos del IVI e IVF en el dosel abierto; Carpinus tropicalis alcanzó un IVF más elevado en el dosel cerrado. Conclusiones: La estructura arbórea fue diferente en las cuatro orientaciones estudiadas y en las dos condiciones del dosel. La mayor diferencia en composición de especies y diversidad se observó entre las orientaciones norte y este, de ellas, la norte presentó los valores más altos de riqueza, especies frecuentes y dominantes.

When roads cross streams: fish assemblage responses to fluvial fragmentation in lowland Amazonian streams

Roads affect biodiversity by increasing mortality rates, habitat loss, and natural landscape fragmentation. Poorly installed culverts can impound streams, changing the environmental conditions, and affecting aquatic communities. We evaluated the effects of road crossings on the taxonomic composition and functional structure of fish assemblages in lowland eastern Amazonian streams, Brazil. We tested the hypothesis that the presence of road-derived impoundments affects assemblage taxonomic and functional composition and structure. Two predictions were addressed: (1) Species and functional group composition will differ in impounded reaches in relation to lotic reaches; (2) Assemblages in downstream lotic reaches will be richer in species and functional groups in relation to upstream lotic and impoundment reaches. We sampled five streams crossed by roads presenting impoundment formation, conducted by visual census (day, dusk, and night) in 200 m line transects. Assemblage composition from lentic reaches was different from lotic reaches, and Shannon diversity from downstream reaches was different from upstream and impoundment, however, beta diversity partitioning between lotic reaches showed higher nestedness contribution, reinforcing the role of impoundment in limiting fish dispersal between lotic reaches. These results suggest that impoundments impose environmental and dispersal constraints to fish, affecting their longitudinal distribution in streams fragmented by roads.(AU)

Estradas afetam a biodiversidade aumentando as taxas de mortalidade, perda de hábitat e fragmentação. Cruzamentos mal instalados represam riachos, alterando as condições ambientais e afetando as comunidades aquáticas. Avaliamos os efeitos deste impacto sobre a estrutura taxonômica e funcional das assembleias de peixes em riachos da Amazônia Oriental, Brasil. Testamos a hipótese de que a presença dos alagados derivados de estradas afeta a composição e estrutura taxonômica e funcional das assembleias. Nossas predições foram: (1) A composição de espécies e grupos funcionais é diferente entre trechos alagados e lóticos; (2) Assembleias nos trechos à jusante serão mais ricas em espécies e grupos funcionais que os trechos à montante e alagados. Amostramos cinco riachos cruzados por estradas com formação de alagamentos por censo visual (dia, crepúsculo e noite) em transectos lineares de 200 m. A composição das assembleias dos trechos lênticos diferiu dos lóticos, e a diversidade de Shannon à jusante diferiu dos trechos montante e alagados, entretanto, nos lóticos, houve maior contribuição do aninhamento na partição da diversidade beta, reforçando o papel do represamento na limitação da dispersão de peixes entre estes. Sugerimos que os represamentos impõem restrições ambientais e de dispersão aos peixes, afetando sua distribuição longitudinal em riachos fragmentados por estradas.(AU)

The Nursing Minimum Data Set (NMDS) and Its Relationship with the Nursing Management Minimum Data Set (NMMDS): significance, development, and future of nursing profession / 간호학회지

No Abstract available.