Palynological Analysis Of Myotragus balearicus Coprolites. The Extinction Of Animal And Vegetal Species During The Holocene in The Balearic Islands (Spain).

Yll, R. (1); PÚrez-Obiol, R.(1) & Alcover, J.A.(2)
    (1) Departament de Biologia Animal, Biologia Vegetal i Ecologia, Unitat de BotÓnica, Universitat Aut˛noma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
    (2) Institut Mediterrani d'Estudis Avanšats (CSIC-UIB), Cta de Valldemossa km 7,5, 07071 Ciutat de Mallorca, Balears, Spain.

The Balearic Islands are located in a very critical biogeographic position with respect to the oscillations that dominated the climate during the Quaternary. The study of the evolution of the landscape in these islands shows that the processes of change have been more evident in comparison with the continent. A radical change of the landscape registered during the Holocene implied the medium term disappearance of some vegetal and animal species. The extinction of Hypnomys morpheus, Nesiotites hidalgo and, specially, of Myotragus balearicus are well documented. Myotragus balearicus was a ruminant exclusive of the Balearic Islands. The first human inhabitants settled in the Balearic islands coexisted with Myotragus until the species became extinct, at about 4,000 years ago. The unusual morphology of Myotragus balearicus has originated speculations on its diet.

The fact that Myotragus balearicus lived under insular conditions implies that particular adaptations to the pre-human environments have been done. Likewise, Myotragus balearicus has been played an important role within the insular ecosystems of the Balearic islands and could be related with the evolution and the transformation of the Balearic flora.

Coprolites of Myotragus balearicus have been collected during several excavation campaigns and palynological analyses were carried out. Pollen analyses reveal that Buxus balearica (a toxic plant) was involved in the habitual diet of Myotragus balearicus, being a source of great importance. Buxus balearica was an abundant pant in the landscape until the mid Holocene and, afterwards, reduced its presence dramatically. This fact could have been related with the cause of the reduction of its presence in the Balearic Islands. It is difficult to assign a simple causal relation between the extinction of Myotragus balearicus and this plant. In addition, this disappearance is produced synchronically with the abrupt climatic change registered in the Mediterranean during the V millennium BP and with the expansion of the human presence in the Balearic Islands. These considerations open a debate that must consider the relation between these extinction and their explanation from climatic or anthropic causes.