Floristic and structural characterization of the plant communities of the Tova-Tovita island complex (Chubut, Argentina), under degradation scenarios.

Abstract

Island systems constitute fragile ecosystems of high biological value, where small disturbances can cause profound changes in the structure and composition of the vegetation. The Patagonia Austral Interjurisdictional Marine Coastal Park (PIMCPA) protects a group of islands and coastal areas in northeastern Chubut, Argentina, for which there is limited floristic information. This study presents, for the first time, a systematic characterization of the flora and an evaluation of ecological parameters of the soil and vegetation (litter, standing dead, bare soil, and vegetation cover) in the plant communities of the Tova-Tovita island complex. The surveys were carried out using the Holistic Floristic Method for arid, semi-arid, and sub-humid areas. Three landscape units were identified: zampa steppe with grasses and mata jume steppe (Isla Tova), and zampa steppe without grasses (Isla Tovita). A total of 48 species belonging to 42 genera and 14 families were identified, with Amaranthaceae, Poaceae, and Aizoaceae being the most representative. Isla Tovita showed significant differences in the analyzed parameters (vegetation cover, bare soil, standing dead vegetation, and litter) compared to Isla Tova, indicating greater degradation at this site. These patterns are observed within a context of persistent disturbances associated with the presence of herbivorous and nesting fauna on the island complex. These results constitute a baseline for future assessments of the dynamics and conservation of the island vegetation of the PIMCPA.