Guanacos, arbustos espinosos y la historia evolutiva del pastoreo en las estepas Patagónicas
Resumen
Field observations while traveling through the Patagonian steppe over the past 15 years have left me with a clear impression of how well defended many of the plants are against herbivory. The objectives of this paper are to question the prevailing hypothesis that the evolutionary history of herbivory in Patagonia has been short and to ask if there is any evidence to support an alternative hypothesis of a long evolutionary history. The analysis is entirely speculative based upon personal observations, discussions with colleagues and a diverse selection of material from the literature. My conclusion from this analysis is that there is at least enough support for an alternative hypothesis to justify proposing it. Furthermore, the long evolutionary history hypothesis is consistent with observations of frequent herbivore defenses among the dominant plants and relative resistance of upland sites to large negative effects of 100 years of herbivory by sheep.
Citas
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