Frugivory by native (Lycalopex spp.) and allochthonous (Canis lupus familiaris) canids reduces the seed germination of litre (Lithrea caustica) in central Chile

Abstract

The consumption of seeds by animals can increase the germination probability because of seeds passage through animal guts. The loss of a native disperser by anthropogenic threats might be compensated by generalist alien seed dispersers. The aim of this work was evaluating the role of dogs (Canis lupus familiaris) and foxes (Pseudalopex spp.) for seed germination of the native fleshy-fruited tree Lithrea caustica. The effectiveness of dogs and foxes as seed dispersers of L. caustica was estimated through seed germination and post-germination viability of seeds obtained from faecal samples plus a control given by seeds collected directly from plant branches. Eleven replicates per treatment and 20 seeds per replicate were used. The experiment takes place 18 weeks with an ad libitum water supply (thermoperiod: 25.7 ± 0.1 °C/12.7 ± 0.2 °C, photoperiod: 12 h light/12 h darkness). Maximum germination occurred the week 18. The germination percentage of seeds consumed by dogs (24.5 %) did not differ significantly from the germination percentage of seeds consumed by foxes (28.2 %), although it was lower than that observed from the control (45.5 %). The post-germination viability of seeds did not differ significantly among types of seed consumers, although there was a tendency toward a lowered viability in seeds dispersed by dogs (40.5 %) rather than by foxes (80.7 %). Consequently, dogs eventually can surrogate the seed disperser role of foxes, although both mutualist animals seem to be inefficient seed dispersers of Lithrea caustica, because dogs and foxes decrease the germination capability of this fleshy-fruited native tree from central Chile.