Exploring the Spatial Dynamics of Endangered Nothofagus alesandrii and Its Relationship with Geomorphometric Variables and Native Tree Species in a Stand of Its Northern Distribution

Abstract

Nothofagus alessandrii is an endangered species with limited and fragmented distribution in the Maule coastal forest of central Chile. Understanding the factors and processes that influence the natural growth of this species is crucial for mitigating its ecological vulnerability. The primary objective of this research is to determine the spatial distribution pattern of N. alessandrii and its association with geomorphometric variables (slope, elevation, and exposure), as well as its association with other tree species in a representative forest located in the northernmost natural distribution range of the species. To achieve this, the coordinates (x, y, z) of all N. alessandrii individuals and accompanying tree species, along with their slope, elevation, and exposure, were obtained using a total station. A spatial analysis tool based on distance indices (SADIE) was used to quantify the spatial pattern of N. alessandrii and detect local aggregates, as well as determine the degree of spatial association between pairs of variables. The results showed that N. alessandrii trees had a random distribution pattern and a significant spatial association with the studied geomorphometric variables. An additional significant finding was the lack of spatial association observed between N. alessandrii and the accompanying species. In conclusion, our study provides valuable information on the spatial distribution and ecological correlates of the endangered N. alessandrii in a fragmented forest ecosystem of central Chile. The results highlight the importance of geomorphometric variables in shaping the distribution pattern of the species, which can be used to guide restoration and conservation efforts.