Degraded forests display novel plant species assemblage: implications for sustainable livestock management in Southern Patagonia

Abstract

Extensive livestock management implicates the use of a mosaic of habitats (grassland, forest patches, edge areas, deforested areas, etc.) by animals in the same productive unit. Many degraded forestlands have been converted to grasslands altering the original species composition to achieve productive goals (forage). Sustainable livestock management should consider the specific composition of natural habitats and that of altered forests. We evaluate differences in species assemblage, ground cover diversity and productive attributes between natural habitats and degraded forests found in extensive livestock ranches of Tierra del Fuego (Argentina). Vegetation sampling was carried out in four different habitats: (i) forest, (ii) forest-grassland edge, (iii) native grassland and (iv) degraded forest or “capado”. We assessed their community assemblages through Non-metric multidimensional scaling (NMDS) and multi-response permutation (MRPP) analysis, and further explored their differences regarding their indicator species and ground cover diversity index. As expected, in our study area, the forest and the grassland presented their own contrasting plant communities. The forest-grassland edge presented a heterogeneous transitional community. Finally, the capado presented a novel plant assemblage, determined by past legacies of the original degraded forest and surrounding habitats, but also strongly affected by accumulated disturbances. Moving apart from the forest degraded vision towards considering the capados as novel ecosystems could shed light on new tools and approaches to take these systems towards desired future ecological conditions. Understanding these ecosystems and exploring their potential can improve the formulation of integrated agroforestry practices of Nothofagus forests in Tierra del Fuego, Argentina.