Changes in Structure and Diversity of Woody Plants in a Secondary Mixed Pine-Oak Forest in the Sierra Madre del Sur of Mexico

Roberto Almazán-Núñez,Liliana Parra-Juárez,Grégory Charre,Javier Jiménez-Hernández,Pablo Corcuera

doi:10.3390/f7040090

Abstract

The biotic province of the Sierra Madre del Sur presents a mosaic of woodlands at different successional stages due to frequent modifications in land use. In this study, we analyzed changes in woody flora across three successional stages of pine-oak forest: early, intermediate, and mature. Vegetation composition and diversity were characterized in 10 plots (each 0.28 ha). The mature stage had the highest values for species richness, abundance, and diversity. Pioneer plants were dominant in the early-successional site and may promote the establishment of late-successional species. The vegetation structure was more complex in the mature stage, where members of the Quercus genus were co-dominant with Pinus species. Pine tree richness was highest in the early-successional stage, and its abundance increased at the intermediate-successional site. These results suggest that Pinus species can grow in perturbed and sunny environments but also require favorable edaphic and microclimatic conditions, such as those found in intermediate woodlands. Results of this fieldwork support the initial floristic composition succession model, which suggests that species present at early stages will also occur in subsequent stages. Ecological succession may be considered to be a natural restoration process, and thus, conservation strategies should focus on maintaining distinct successional communities in addition to mature forests in order to preserve a high number of species.

Highlights

Pine-oak woodlands provide environmental goods and services, such as the conservation of biological diversity, carbon sequestration, and the regulation of climate and hydrological cycles [1,2,3], in Mexico and other parts of the world these forests have undergone anthropogenic modifications due to agriculture [4] and overharvesting [5,6]
We recorded 892 individuals in the three successional stages, corresponding to 19 shrub species and 34 tree species belonging to 20 families (Table A1)
The highest relative importance value (RIV) in the early stage corresponded to Brickellia spp., Pinus lawsonii Roezl ex Gordon., Acacia farnesiana (L.) Willd., Pinus pringlei Shaw., and Crataegus pubescens

Summary

Introduction

Pine-oak woodlands provide environmental goods and services, such as the conservation of biological diversity, carbon sequestration, and the regulation of climate and hydrological cycles [1,2,3], in Mexico and other parts of the world these forests have undergone anthropogenic modifications due to agriculture [4] and overharvesting [5,6]. Temperate forests are susceptible to fires, landslides, and storms [7,8,9]. Disturbed forests have an open canopy that leads to less fertile soils due to a lower incorporation of organic matter [1]. This open canopy may promote variations in understory temperature and humidity [20]. These changes can limit the regeneration of many tree species [6,21]. The presence of dominant Pinus (pine) and Quercus (oak) species may strongly influence seedling recruitment rates, including those of other tree species [22]

Methods

Results

Conclusion