Impacts of Global Change on the Spatial Dynamics of Treeline in Venezuelan Andes

Eulogio Chacón-Moreno,Daniela Paredes,Patricia Suárez Del Moral,Mayanín Rodríguez-Morales,Anderson Albarrán

doi:10.3389/fevo.2021.615223

Eulogio Chacón-Moreno, Daniela Paredes + Show 3 more

Open Access

https://doi.org/10.3389/fevo.2021.615223

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Abstract

The treeline in the Andes is considered an essential ecotone between the Montane forest and Páramo. This treeline in the Venezuelan Andes corresponds with a transitional ecosystem defined as the Páramo forest. In this work, we identify and analyze the impact of climate warming and land transformation as agents altering the Páramo forest ecosystem’s spatial dynamics along the Venezuelan Andes’ altitudinal gradient. We carry out multitemporal studies of 57 years of the land transformation at different landscapes of the Cordillera de Mérida and made a detailed analysis to understand the replacement of the ecosystems potential distribution. We found that the main ecosystem transition is from Páramo to the Páramo forest and from Páramo to the Montane forest. Based on the difference between the current lower Páramo limit and the Forest upper limit for 1952, the treeline border’s displacement is 72.7 m in the 57 years of study, representing ∼12.8 m per decade. These changes are mainly driven by climate warming and are carried out through an ecological process of densification of the woody composition instead of the shrubland structure. We found that Páramo forest ecosystems practically have been replaced by the Pastures and fallow vegetation, and the Crops. We present a synthesis of the transition and displacement of the different ecosystems and vegetation types in the treeline zone. The impact of climate warming and deforestation on the Páramo forest as a representative ecosystem of the treeline shows us that this study is necessary for an integrated global change adaptation plan.

Highlights

Global change impacts biodiversity by different drivers acting at the global and regional scales (Sage, 2020)
Species can respond to climate change, with a vertical migration in a short distance (e.g., 500 m to counteract an increase of 3◦C) (Peñuelas et al, 2002); the acceleration in the rate of increase in plant species richness (Steinbauer et al, 2018), with the local difference concerning to conditions as topography (Pauli and Halloy, 2019), and diversity of different spatial patterns for treeline dynamics (Bader et al, 2020)
The landscape ecology approach used in the research allowed us to obtain maps of vegetation and ecosystems, with different time scales, to evidence the impacts of global change in the treeline’s spatial dynamics in the Venezuelan Andes

Summary

Introduction

Global change impacts biodiversity by different drivers acting at the global and regional scales (Sage, 2020). Species can respond to climate change, with a vertical migration in a short distance (e.g., 500 m to counteract an increase of 3◦C) (Peñuelas et al, 2002); the acceleration in the rate of increase in plant species richness (Steinbauer et al, 2018), with the local difference concerning to conditions as topography (Pauli and Halloy, 2019), and diversity of different spatial patterns for treeline dynamics (Bader et al, 2020). Most of these researches are focused on temperate alpine regions, but few on subtropicaltropical alpine regions (Pauli and Halloy, 2019)

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