Seed dispersal distance, seed morphology, and recruitment in the Chilean sclerophyllous tree Quillaja saponaria: implications for passive restoration in a semiarid ecosystem

Abstract

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 Communicated by Michelle Tedder.

Facilitation by pioneer trees and herbivore exclusion allow regeneration of woody species in the semiarid ecosystem of central Chile

“…The goal of this study was to assess the effect of the exclusion of large and medium‐sized mammal herbivores and the presence of V. caven , on the natural regeneration of woody native species of the sclerophyllous forest in central Chile. This study was conducted through a seven‐year exclusion experiment in V. caven savannas adjacent to remnant forest fragments, from where propagules can be dispersed by birds and wind (Miranda et al, 2019; Vásquez et al, 2021). We monitored and analyzed the regeneration annually in order to evaluate the effects of herbivore exclusion and the presence of V. caven over time after exclusion.…”