Native dispersers induce germination asynchrony in a macaronesian endemic plant (Rubia fruticosa, Rubiaceae) in xeric environments of the Canary Islands

A comparison of the germination rate of a Macaronesian endemic plant (Rubia fruticosa) between two xeric badland areas of the easternmost islands of the Canaries (Lanzarote and Fuerteventura) is presented. A similar germination rate was observed between both seed control plants front the populations of Lanzarote and Fuerteventura in the two years. However, some germination asynchronies were observed when the native frugivores participated in this seed dispersal system; seeds from Lanzarote germinated earlier than in Fuerteventura when they were consumed by lizards and birds. Although this pattern did not present a between-year consistency, seeds germinated earlier in the more stressed badland even when climatic differences are not so great. This asynchrony, caused by frugivorous dispersers (lizards and birds), is important in geographical zones where rain is unpredictable and where it increases the probability that seedlings can recruit Successfully and for a longer period. (c) 2005 Elsevier Ltd. All rights reserved.