Leaf litter hides post-dispersed seeds from invasive alien removers in a sclerophyll forest in central Chile

Luis Cáceres-Polgrossi,Alvaro G Gutiérrez,Alvaro Promis

doi:10.5424/fs/2020293-16845

Abstract

Aim of the study: Seed removal may be a determining filter for regeneration. Factors such as leaf litter, tree cover and seed density affect seed removal. This aims to assess three aspects involving on post dispersal seed removal of four woody species (Lithraea caustica, Maytenus boaria, Quillaja saponaria and Retanilla ephedra) of a sclerophyll forest. Study area: Andean Mediterranean sclerophyll forest of Quillaja saponaria and Lithraea caustica located in the Río de Los Cipreses National Reserve, Chile. Materials and methods: Seven experimental plots were set up, in which seeds were offered in an experiment with variations in leaf litter, tree cover and seed density. Generalized Linear Mixed Models (GLMM) were used for the statistical analysis. Camera traps were installed to identify the seed removers. Main results: Q. saponaria seeds were more removed than the seeds of the other species (0.84, observed mean). Whereas that M. boaria and R. ephedra did not show significant differences on the removal of their seeds (0.77 and 0.67 respectively), both were more removed than L. caustica (0.59). The removal of M. boaria, Q. saponaria and R. ephedra seeds was lower in the presence of leaf litter. No factor influenced the removal of L. caustica seeds. Seed removers were identified as invasive alien species such as Rattus sp. and Oryctolagus cuniculus and native species such as Lycalopex culpaeus. Research highlights: Three woody species of this forest suffer severe seed removal by invasive alien fauna with major implications for the resilience of these forests. The coverage of leaf litter is key to hide away the seeds, increasing survival and could promote germination. Keywords: invasive alien fauna; Mediterranean forest; sclerophyll forest; seed removal factors.

Highlights

The Central Chile forest is part of the five regions in the world with Mediterranean ecosystems
73 % of the photographs that were taken at sites with tree cover showed rodents of the genus Rattus removing the seeds offered, 18 % showed individuals of O. cuniculus and 9 % L. culpaeus (Table 2)
Our study reports on the relevance of the removal of seeds dispersed of a sclerophyll forest in Central Chile

Summary

Introduction

The Central Chile forest is part of the five regions in the world with Mediterranean ecosystems These regions hold almost 20% of the world’s flora (Cowling et al, 1996), have a high level of endemism (Naveh & Wittaker, 1979; Arroyo & Uslar, 1993; Arroyo et al, 1993; Cowling et al, 1996) and cover less than 5% of the world's surface (Cowling et al, 1996). These regions are recognized as biodiversity hotspots due those important biodiversity characteristic and the large number of threatened species by anthropogenic impacts (Myers et al, 2000). Today the forest is heavily fragmented and it has been suggested it has problems with its regeneration process, with little recuperative capacity (Jiménez & Armesto, 1992; Schulz et al, 2010)

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