Comparison of Natural Regeneration in Natural Grassland and Pine Plantations across an Elevational Gradient in the Páramo Ecosystem of Southern Ecuador

Abstract

During the 1980s, reforestation programs using exotic species (Pinus spp.) were established in the páramo ecosystem of Ecuador. The aims of this study were: (1) to compare the natural regeneration between pine plantations (Pi) and natural grassland (NG) across an elevational gradient and (2) to identify the attributes of Pi and soil properties that were influencing herbaceous and woody plant composition and their plant cover. In total, six independent Pinus patula (Schltdl. & Cham. plantations (two per each elevation) were selected and distributed in an elevational range (3200-3400, 3400-3600, 3600-3800 m a.s.l.). Adjacent to Pi, plots in NG were established for recording natural regeneration. Both, namely the attributes and the soil samples, were measured in Pi. The results showed that natural regeneration differs significantly between both types of vegetation. As expected, NG holds more plant diversity than Pi; the elevational range showed a clear tendency that there was more herbaceous richness when elevation range increases, while the opposite was found for woody species. Moreover, attributes of Pi influenced herbaceous and woody vegetation, when saturated hydraulic conductivity (Ksat) in the soil, basal area (BA) and canopy density (CD) increased, herbaceous species richness and its cover decreseased; and when Ksat and the acidity in the soil increased, woody plants richness and its cover decreased. The plantations have facilitated the establishment of shade tolerant species. More studies are needed to evaluate if removal with adequate management of pine plantations can improve the restoration and conservation of the native vegetation of the páramo ecosystem.Forests 2019, 10, 745 2 of 30 diversity of the ecological conditions linked to the glacial geomorphology that has resulted in a large number of different plant associations, each one with their typical species [6].Elevation is an important factor that shapes plant diversity in the páramo. The elevational gradients combine sets of environmental conditions such as: temperature, wind velocity, atmospheric gas composition, water availability, nutrient deposition and cycling, soil weathering and solar radiation, all of which determine the composition and structure of vegetation [7]. Based on the influence of these factors and vegetation structure, the páramo has been divided into three zones, from lowest to highest: subpáramo, páramo (páramo grassland) and superpáramo [8]. The subpáramo, also called páramo forest, shrubby páramo, subpáramo woodland and subpáramo elfin forest [9], is the transition zone (ecotone) between the forest (upper montane cloud forest) and the páramo grassland [8][9][10][11]. The subpáramo is usually an entangle of shrubs and small dispersed trees, gradually reduced in size, that gives way to grasses and herbs [9]. The páramo vegetation zone, also called grass páramo or páramo grassland, is characterized by tussock grasses dominated by species of Calamagrostis and/or Festuca. Finally, above the páramo, there is the superpáramo, which i...

Páramo Ecosystems in Ecuador’s Southern Region: Conservation State and Restoration

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The importance of environmental and disturbance conditions in different growth stages of plants of temperate forest in the Sierra Norte of Oaxaca, Mexico

“…All organisms have unique ecological requirements in which they can carry out their life cycle (Bewley and Krochko 1982). It is essential to understand each aspect of the life cycle, as they may present particular ecological strategies (Bonte et al 2012) such as dispersal (Nathan and Muller-Landau 2000), germination (Pearson et al 2002;Martínez-Villegas et al 2018), regeneration (Quiroz et al 2019), or distribution (Gomez et al 2011). Knowledge of environmental preferences in the different stages of plant growth becomes relevant if this information applies to conservation, restoration, or resource management issues (Wahid et al 2007).…”