Litter chemistry and abiotic effects on plant recruitment success in denuded areas of Patagonian Monte rangelands

BOSCO, T; BERTILLER, M. B.; CARRERA, A.L.

Foz do Iguassu

Congreso; VII World Conference on Ecological Restoration V Congreso Iberoamericano y del Caribe de Restauración Ecológica I Conferência Brasileira de Restauração Ecológica; 2017

Society for Ecological Restoration

Grazing disturbance reduces the cover of preferred species and increase soil gaps in arid ecosystems. Litter amendment is a management tool often used for soil and plant restoration in denuded areas, but its efficacy has rarely been tested in these ecosystems.We evaluated the effect of litter chemistry (C/N ratio) combined with different levels of UV radiation exposure and soil water on 311soil inorganic-N (SNin) and recruitment of two dominant perennial grasses preferred by herbivores (Poa ligularis and Nassella tenuis), one preferred shrub (Atriplex lampa), and one non-preferred evergreen shrub (Larrea divaricata), that has chemical defensesagainst herbivores in denuded areas of the Patagonian Monte, Argentina. Microcosms with soil of denuded areas and seeds ofall species were sown in separated cells, subjected to the combined effects of litter cover (without litter (NL), litter with C/N ratio=15 and C/N ratio =48), UV radiation (near ambient (Am-UV) and reduced (Re-UV)), and volumetric soil water (high (15-25% HSW)and low (5-15% LSW)). We assessed SNin concentration periodically and species recruitment (probability of transition from seed toestablished plant) after six months. Low C/N ratio in litter and Am-UV increased SNin. Soil water enhanced SNin only at one date.Perennial grass species and A. lampa recruitment was increased with augmented SNin. None factor affected the recruitment of L.divaricata. We concluded that litter amendment combined with exposure to UV radiation throughout the effect on soil inorganic Nmay modulate plant recruitment success of species preferred by herbivores in denuded areas.