Co-occurrences and species distribution models show the structuring role of dominant species in the Vez watershed, in Portugal

Knowing the structural role of species within communities is important for their conservation and management in the context of recent/ongoing biodiversity loss. In a community, dominant species can influence the distri-bution and composition of subordinate species. Despite existing research, an approach is lacking to help un-derstand the important role of dominant species in the community, without requiring more detailed data. In this study, we describe an approach to rank the relative importance of plant species within a community based on their abundance and co-occurrence patterns. The Co-occurrence Community Importance Index (CoCII) - a newly proposed index translating the degree of influence that each dominant species has on all its co-occurring sub-ordinate species - was calculated and analysed. We used both abiotic and biotic variables within a species distribution models framework, with data collected in the Vez watershed in the North of Portugal. Our analysis included 114 plants - 26 dominant and 88 subordinate species. Spearman correlations were used to analyse potential interspecific relationships between co-occurring dominant and subordinate species. Using the CoCII, we ranked the relative importance of each dominant species within the plant community. Our results support the role of plant-plant interaction patterns regarding our study area's most highly inter-correlated species. Our approach to ranking species' importance can be directly translated into conservation schemes for managing and maintaining the structure of plant communities. Moreover, it can provide insights into the relative importance of dominant species in a plant community from commonly available datasets including presence-absence, presence-only, or percentage cover data, which allows for the relatively cost-efficient in-field collection and monitoring infield. Furthermore, this approach could allow us to advance the field of community ecology by providing essential information on the species that assure the stability of natural or semi-natural habitats of conservation concern.

Automated summary

Understanding the role of species within communities is crucial for their conservation and management in the face of biodiversity loss. This study presents an approach to rank the importance of plant species within a community based on their abundance and co-occurrence patterns. The newly proposed Co-occurrence Community Importance Index (CoCII) was used to assess the degree of influence that each dominant species had on subordinate species.