Where does the forest come back from? Soil and litter seed banks and the juvenile bank as sources of vegetation resilience in a semiarid Neotropical forest

ENRICO, LUCAS; FORTUNATO, VALENTINA; LIPOMA, MARÍA LUCRECIA; DÍAZ, SANDRA

JOURNAL OF VEGETATION SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Año: 2020

1100-9233

Questions: The existence of reservoirs from which dominant plants recruit after disturbances is a key factor in ecosystem resilience. With this in mind, we ask the following question: where do woody species regenerate from in the semiarid NeotropicalChaco forest? Is land use affecting the floristic composition of biodiversity reservoirs? Are the soil and litter seed banks and the juvenile bank potential sources ofresilience of these forests in the face of different land-use regimes?Location: Chancaní, Northwestern Córdoba, Argentina.Methods: We selected four ecosystem types subjected to increasing long-term landuse intensity: primary forest (no land use in the last 50 years), secondary forest (lowland-use intensity), closed species-rich shrubland (moderate land-use intensity), andopen shrubland (high land-use intensity). We monitored four sites per ecosystemtype where we recorded adults, saplings and seedlings of all woody species. We collected litter and soil samples that were processed in the laboratory for taxonomicidentification and germination of seeds. We compared the floristic composition ofthe soil and litter banks, as well as of the juvenile bank (?biodiversity reservoirs?) withthat of established vegetation of the primary forest, considered as the reference ecosystem. We also compared the established vegetation from sites under land use withthat of the primary forest.Results: Woody species were scarcely represented in the soil, but very well represented in the litter and the juvenile banks from different ecosystem types. These tworeservoirs showed high similarity with the established vegetation of the primary forest. However, as land-use intensity increased, similarity between the reservoirs andthe established vegetation of the primary forest decreased.Conclusion: Litter and juvenile banks, but not the soil bank, are the main reservoirs for the recruitment of new individuals of woody species in the Chaco forest.However, the ability of these reservoirs to act as sources of resilience decreases asland use intensifies.KEYWORDSjuvenile plant bank, land use, litter seed bank, semiarid Chaco, soil seed bank, sources ofresilience