Abstract
(1) Background: Neotropical montane forests represent one of the most diverse world ecosystems; however, they are also among the most threatened ones mostly due to deforestation. Our main goal is to classify and clarify the forest types based on the changes in basal area (BA), tree density, and species composition of montane forests in Southern Ecuador, and to determine the influence of critical environmental and geomorphological factors. (2) Methods: One hundred thirty-two temporary plots of 400 m2 were installed in homogeneous and well-conserved forest stands. We identified and measured all trees >10 cm diameter breast height (DBH). We modeled species diversity (Fisher’s alpha) change in relation to climatic, altitudinal, and geomorphological gradients using 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 a SIMPER analysis to identify the species that contributed most to the floristic dissimilarity among the identified altitudinal forests types. (3) Results: The floristic groups were determined by altitude, temperature, and isothermality, but also some geomorphological variables and lithology were used. Plots located in low hills have higher alpha diversity compared to the high hills and dissected mountains. (4) Conclusions: Altitude is the most important factor responsible for the division of structural and floristic groups. In addition, those plots located on the whitish tuff have higher alpha value diversity compared with plots in andesitic tuffs. Precipitation on the wettest quarter (>839 mm) and isothermality (>90.5) are the most relevant climatic factors driving the floristic classification.
Highlights
Neotropical montane forests represent one of the most diverse ecosystems in the world and very rich biodiversity hotspots [1]
Our results showed significant changes in the floristic diversity, structure, and composition of the species related to the ecological and geomorphological gradients in montane tropical forests
It is recognized that the elevation of the Andes produced the occurrence of particular environments such as our region, with a great diversity of geological landscapes and becoming a unique region with a huge presence of environmental heterogeneity and complex distribution patterns of diversity and ecosystems [36]. This is one of the reasons behind the adaptation and speciation processes found in tropical zones, mainly being found within the mountain forests found in the tropical Andes and considered as the world center of diversity [37,38,39]
Summary
Neotropical montane forests represent one of the most diverse ecosystems in the world and very rich biodiversity hotspots [1]. They are included among the most threatened, especially in those in which deforestation is reaching high rates [2]. In this sense, those located in the Northern Range of Andes Mountains are considered as a conservation priority worldwide [3]. And in spite of the valuable ecosystem services they provide, such as water provisioning and biodiversity, information on their critical ecological determinants is still limited [7]. Some basic questions related to their response to environmental gradients such as altitude, a well-known surrogate of foreseeable climate variation, remain open to discussion
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
