FRUGIVORY OF PLOCAMA-PENDULA (RUBIACEAE) BY THE RABBIT (ORYCTOLAGUS-CUNICULUS) IN XEROPHYTIC ZONES OF TENERIFE (CANARY-ISLANDS)

In this paper we present a new case of the scarcely known phenomenon o f frugivory by the Rabbit. A total of 1,843 seeds of Plocama pendula ( Rubiaceae), an endemic species of the Canary Islands, were found in an analysis of 1;200 faeces collected in three different zones of a ravi ne located on Tenerife island (riverbed, hillside and sloping zone). T he external damage produced by rabbits upon the seeds was relatively l ow (16.5% of broken seeds) and significant differences in germination percentage were found when comparing with control seeds collected on t he plants (plants: 66.5% vs rabbits: 34.5%), Furthermore, seeds from p lants germinated significantly earlier than those from rabbit's droppi ngs. This experiment was performed over two months. In terms of freque ncy of seed occurrences, the highest value was found in the riverbed ( 77.5%), decreasing gradually away from this habitat (16.4% on hillside and 6.1% in the sloping zone). Furthermore, it is in the riverbed whe re the species reaches the highest density of plants. This is a clear case where an introduced herbivore is interacting with the seed disper sal system together with the native frugivore species (lizards and war blers).