Browsing by Author "Becerra, Pablo, I"

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    Burying, not broadcasting seeds improves the seedling establishment of most woody species under different ecological conditions in a semiarid ecosystem of central Chile
    (2022) Becerra, Pablo, I; Aqueveque, Naijem; Velasco, Nicolas
    The importance of the sowing method (broadcasting or burying) for seedling establishment, and the extent to which environmental conditions modulate differences between these sowing methods, are understudied. When seeds are buried, they may be exposed to soil conditions with higher moisture content than broadcast. This advantage may occur especially under drier soil conditions within a semiarid climate, such as with less precipitation, open sites, and in presence of herbaceous layer. In this study we conducted an experiment to compare the seedling establishment of 13 woody species between a buried sowing and broadcast, under different conditions of precipitation, shade, and herbaceous layer in a degraded semiarid grassland of central Chile. For each species, some seeds were sown by burying them to a depth of 1 cm and others were broadcast. Orthogonally, we applied two irrigation treatments to simulate a dry and a rainier year, two shade treatments simulating the canopy of woody plants and open sites (with vs. without), and two treatments of herbaceous layer (without vs. with). Establishment was monitored for 10 months between July 2016 and March 2017. Species richness of established seedlings was greater when seeds were buried than broadcast under all environmental conditions. The seedling density per species was greater when seeds were buried than broadcast in nine species, although in some cases this depended on environmental conditions. We conclude that, burying seeds of woody species is more effective and can be a widely applicable restoration method for different environmental conditions and species in semiarid ecosystems.
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    Seed dispersal distance, seed morphology, and recruitment in the Chilean sclerophyllous tree Quillaja saponaria: implications for passive restoration in a semiarid ecosystem
    (2022) Vasquez, Inao; Miranda, Alejandro; Delpiano, Cristian A.; Becerra, Pablo, I
    Recolonization of wind-dispersed tree species in degraded areas may decline with distance from remnant forest fragments because seed rain frequently decreases with distance from the seed source. However, regeneration of these species may be even more limited to sites close to the seed source if dispersal distance is negatively affected by seed mass, and germination probability is positively affected by seed mass. We evaluated these hypotheses in a Mediterranean-type ecosystem of central Chile, using the wind-dispersed tree species Quillaja saponaria. We assessed the seed rain curve in a degraded open area adjacent to a remnant forest fragment of this species, and related seed mass with dispersal distance from the seed source. Then, we evaluated the relationship between seed mass, germination, and seedling growth, and if seeds that fall nearer the seed source have greater germination probability. We found a decreasing seed rain with the distance from the seed source. Seed mass was not related to dispersal distance, although seeds with higher wing area dispersed further. Germination probability was significantly and positively related to the seed mass. We observed no significant relationship between distance and germination probability. We conclude that germination probability of this species does not vary along the seed rain curve, and that the recruitment density would be greater near the seed source only due to decreasing seed rain with distance. Our results suggest that this species has the potential to be passively restored in degraded areas, especially within the first 70 m from the remnant forest fragments.