CONICET | Buscador de Institutos y Recursos Humanos

Above-ground herbivory has a direct impact on plant life cycles, particularly at more sensitive stages, due to reduction of vegetative biomass. However, this effect may not be negative if it results in net biomass compensation. As sapling stage could be the best stage for native species to be outplanted, understanding the impact of aboveground herbivory on tree saplings is necessary for restoration purposes. We studied the effect of herbivory on saplings of Ochetophila trinervis (Rhamnaceae), a native woody species from North-west Patagonia, which forms an actinorhizal symbiosis with the N2-fixing actinobacteria Frankia. This tree species has the potential to be used for recovering degraded lands. Nevertheless, there is a perplexing contradiction between the high seed output of O. trinervis and the scarcity of saplings in the field. For 4 months, 1-year-old O. trinervis saplings were exposed to aboveground herbivory by generating different protection degrees (unprotected, protected against some kind of walking herbivores?protected saplings; and protected against all kind of walking herbivores?excluded saplings). The impact of herbivores over sapling survival was minimal (92 ± 3%, mean ± SE) and it was similar among saplings exposed to different protection degrees. The highest frequency of foliar damage in excluded saplings suggests the attack of flying herbivores. The increased emergence of new sprouts and root length growth in saplings highly damaged by herbivores (about three fold and two fold higher than in excluded saplings, respectively), evidenced the capacity of O. trinervis to develop a compensatory growth. The results contradict the assumption that herbivory explains the low density of saplings despite high seed production. Given the high-sapling survival and biomass compensation of O. trinervis after herbivory, we suggest that this species might be appropriate for restoration of degraded areas in the region.