Invasive alien species patterns of association and distribution in an altitudinal gradient of páramo ecosystem

Abstract

The Páramo ecosystem is a unique ecosystem in the high mountains of tropical regions on our planet. However, it is also a vulnerable ecosystem to environmental changes such as temperature, humidity, precipitation, and weather phenomena. Additionally, it faces significant human activities in nearby regions, such as agriculture, grazing, deforestation, the construction of roads, and new settlements. With the recent population growth in these high mountain areas, the Páramo has experienced a negative impact associated with introduced species that affect the ecosystem's structure and functionality. This study aims to characterize and predict the spatial behavior of invasive alien species based on human activities and their impact at different altitudes. The analysis considers variables of invasive alien species presence and distribution, as well as additional parameters collected in the field, such as soil moisture and pH at elevations close to vehicular roads. The methodology used in this study is based on the MIREN study protocol, which analyzes small study areas at different elevations, complemented using multispectral imagery obtained through aerial drone flights. Subsequently, the information was subjected to statistical treatment, and a GLS model was generated. The main result observed is how soil relative humidity and pH parameters are altered based on distance from roads, contributing to changing soil conditions and facilitating the success of invasive alien species. Additionally, the presence of invasive alien species varies depending on elevation, with species like Trifolium repens or Rumex acetosella being more likely to be found in higher areas, while Rumex acetosa and Holcus lanatus are favored in lower zones. Another significant finding is that abundance is higher in areas with grazing activities, especially grasses like Anthoxanthum odoratum and Holcus lanatus, which show greater abundance compared to less affected areas. In conclusion, land use and elevation play a crucial role in invasive alien species abundance in high mountain ecosystems. In terms of alien species presence, regardless of land use or elevation, some alien species have already established themselves and secured a presence in the ecosystem. Otherwise, this study highlights the need to establish spatial monitoring of invasive alien species in high mountain areas. It would be highly beneficial to conduct temporal monitoring of the study zones to track changes over time. Furthermore, expanding the study area to different regions and latitudes where high mountain ecosystems are present would provide valuable insights.