Geomorphology and Altitude Effects on Diversity and Structure of Vanishing Montane Forest of Southern Ecuador

Abstract

1) Background: Neotropical montane forests represent one of the most diverse ecosystems; however, they are also the most threatened for deforestation. Our main goal is to evaluate the change in Basal Area (BA), Density and Species Composition of montane forests in the southern Ecuador and to determine the influence on some critical ecological and geomorphological factors. 2) Methods: One hundred thirty-two temporary plots of 400 m2 each were installed; we identified and measured all trees> 10 cm DBH. We modeled species diversity (Fisher’s alpha) change in relation to climatic, elevational and geomorphological gradients with GLM and Kruskall-Wallis analyses. The change in composition was determined using Cluster Analyses (BIOENV analysis followed by a LINKTREE procedure). Non-metric multidimensional scaling (NMDS) was used to analyze changes across climatic and geomorphological gradients. Finally, we used SIMPER analysis to identify the species that contributed most to the dissimilarity among the different elevations. 3) Results: Formation of floristic groups was influenced by altitude, temperature and Isothermality; physiographic province, great landscape, geological landscape and lithology. Plots located in low hills have higher alpha diversity with respect to the high hills and dissected mountains. 4) Conclusions: The elevation is first hierarchical factor responsible of the division of structural and floristic groups. Plots located on the whitish tuff have a higher alpha value diversity compared with plots in andesitic tuffs. Wettest quarter (> 839 mm) and Isothermality (> 90.5) are the climatic factors that driven de floristic divisions.

Seeing the wood despite the trees: Exploring human disturbance impact on plant diversity, community structure, and standing biomass in fragmented high Andean forests

“…Overall, these figures also compare well to those reported for high Andean forest ecosystems (2,300–2,900 m) in Southern Ecuador by Cabrera et al. (2019), who used a higher DBH threshold (10 cm) and obtained about 21 tree species and an average value of 2.44 for Shannon's diversity.…”

Forests over limestone in Guiuan, Eastern Samar, the Philippines: Species composition and influencing environmental factors

“…Anthropogenic disturbances have influenced vegetation in tropical forests of the Philippines particularly in GMPLRS. Human disturbances are widely believed to reduce species richness in tropical forest landscapes (Buot and Osumi 2011;Sopsop and Buot 2013;Nguyen et al 2015;Imani et al 2016; Van and Cochard 2017;Cabrera et al 2018;Gilbert et al 2020), as observed in the disturbed plots, such as GUI 08 (lowest elevation) and GUI 01 (highest elevation) (see Table 4). The results of this study agree with the findings of Sopsop and Buot (2013) in the Aborlan Guba System, that the lowest and highest portions of the forest experienced the greatest degree of human disturbance, with the former heavily impacted by kaingin farming or shifting cultivation and the latter by clearing due to resource harvesting.…”

Distribución espacial de Pinus y Quercus en un gradiente altitudinal de bosque templado en Guadalupe y Calvo, Chihuahua

“…En el Nivel 1 se presentaron cuatro especies de Pinus. Es importante señalar que la presencia y patrones de la vegetación a lo largo de los gradientes altitudinales se generan debido a la interacción compleja de diversos factores tales como la altitud, la exposición a la radiación solar y la posición topográfica de las poblaciones vegetales, entre otros elementos observables (Girardin et al, 2014;Jadán et al, 2017;Cabrera et al, 2019).…”