Impact of protection methods and abiotic factors on Nothofagus pumilio seedlings mortality in Torres del Paine National Park, Chile

Abstract

National parks (NP) are the last refugia of forests dominated by the Nothofagus species in Chile. However, frequent, careless human-caused fires are destroying these forests even within the national parks. After large-scale fires, N. pumilio stands are unable to recover naturally neither in generative nor in vegetative ways and artificial regeneration must be resorted to in order to maintain their extent. However, even artificial regeneration is not successful without protection against browsing. Therefore, the aim of this study was to experimentally test a range of repellents and other methods of mechanical protection of seedlings against browsing. Five replicates of plots were placed in Torres del Paine NP, in different habitat conditions and with different methods of protection against browsing (11 repellents, wire mesh, plastic tube and control). In each plot, 12 seedlings were treated with each type of protection. In our experiment, only 8% of the seedlings were damaged by browsing, while the mortality rate was 38%. The results indicate a more significant effect of abiotic factors (mainly frost, drought or wind) on seedling mortality than browsing. In parallel, however, it is clear that, compared with the control, six of the eleven repellents used in the experiment showed a significantly positive effect. We suggest the use of plastic tubes as the best option to protect seedlings, which, in addition to providing 100% protection against browsing, are likely to provide more favourable microclimatic conditions for seedlings, similar to leaving the burned snags.