Afinidad fitogeográfica y papel sucesional de la flora leñosa de los bosques de pino‑encino de los Altos de Chiapas, México

Abstract

RESUMENEl análisis de la estructura de varias etapas serales de los bosques húmedos de pino-encino de Los Altos de Chiapas permitió establecer un papel sucesional particular para los distintos grupos de afinidad florística que los componen. La mayoría de los elementos holárticos muestran amplia regeneración en etapas sucesionalmente tempranas, mientras que la de muchos de los elementos andinos y de afinidad con el este de Asia sólo ocurre en condiciones más avanzadas. La estructura y la composición de estos bosques parecen resultar de una mezcla de especies pertenecientes a géneros de origen diverso, cuya coexistencia local depende de su propia tolerancia a las condiciones ambientales que se crean durante la sucesión forestal. Las especies del dosel superior, que pertenecen a géneros de afinidad holártica, juegan un papel central al determinar las condiciones ambientales del interior del bosque, a las cuales se encuentran supeditadas la mayoría de los demás componentes leñosos, especialmente los del grupo de afinidad andina. ABSTRACTA successional role for each phytogeographical group of seral stands of the pine-oak forests in the Highlands of Chiapas (southern Mexico) could be established after their structural analysis. Most of the Holarctic elements regenerate in early successional conditions, while the regeneration of many Andean and East Asian elements is restricted to the more advanced stands. Forest structure and floristic composition appears as the result of a mixture of species belonging to genera of diverse origin. Their local coexistence seems to depend on their tolerance to those environmental conditions resulting from forest development through succession. We ascribe a central role to the canopy species belonging to Holarctic genera which determine the understory microhabitat for most of the remaining woody species, notably for those of Andean affinity. Acta Botánica Mexicana (1993), 21:43-57 1 Subsidiado por la Secretaría de Programación y Presupuesto y el CONACYT mediante una subvención (P218CCOC880612) otorgada a MGE.

Regeneration patterns in relation to canopy species composition and site variables in mixed oak forests in the Sierra de Manantlán Biosphere Reserve, Mexico

“…It is important to highlight that in the study area, oak species were not dominating the understory, according to their intermediate frequency and density values ( Table 1). Our results are in accordance with a study undertaken in southern Mexico ( Quintana‐Ascencio & González‐Espinosa 1993) where oak species do not regenerate below their own canopies and, when this occurs, they represent one or two acorn crops, they have low survival rates and seedlings from a single cohort may die before the next good acorn crop occurs in the stand. In this way, the rapid rate of seedling disappearance results largely from shade intolerance of oak reproduction and the low light levels in the understory.…”

“…In this way, the rapid rate of seedling disappearance results largely from shade intolerance of oak reproduction and the low light levels in the understory. Moreover, it is widely known that the establishment and initial growth stage is one of the most critical in the process of oak regeneration ( Carvell & Tryon 1961; Quintana‐Ascencio 1989). In our study area, oak species were dominating the canopy (which could be explained by their asexual reproduction through stump and root sprouting), but we have to consider that the chance of a species reaching the canopy in large gaps is predicted by the local environment (e.g.…”

Successional changes in soil, litter and macroinvertebrate parameters following selective logging in a Mexican Cloud Forest

“…Although the environmental and vegetation shifts associated with post-logging secondary succession in TMCF have been studied in detail (González-Espinosa et al, 1991;Quintana-Ascencio and González-Espinosa, 1993;Romero-Nájera, 2000;Blanco-Macias, 2001;Galindo-Jaimes et al, 2002), little is known about the consequences of these long-term changes on nutrient budgets and faunal communities below-ground. In Mexico, tree species of Holarctic phytogeographic origin (such as Pinus spp.)…”

Genetic diversity of Oreopanax xalapensis (Araliaceae) in the Highlands of Chiapas

“…El presente estudio sugiere que O. xalapensis en Los Altos de Chiapas es genéticamente diversa y esta diversidad está contenida en las subpoblaciones, ya que al menos tres poblaciones (Bazom, Huitpec, Mitzitón) tuvieron una diversidad mayor al promedio. Se considera que Oreopanax xalapensis es una especie de fase sucesional intermedia a madura del BMM (Quintana-Ascencio y González-Espinosa, 1993;González-Espinosa et al, 2007b), es tolerante a moderados niveles de perturbación y resiste radiación solar directa en estado adulto (Meave et al, 1992;Ramírez-Marcial, 2003;QuintanaAscencio et al, 2004) ser alto (Ruiz-Ruvalcaba, 2004;Mejía-Domínguez, 2006) en especial en boques incipientes o fases temprana de la sucesión (Vera-Maloof, 2009), pude llegar a reproducirse sincrónicamente a temprana edad (a alturas inferiores a los 3 m y diámetros < 3 cm; N. Ramírez-Marcial, obs. pers.).…”