Human ecological impacts on islands: Exemplified by a dwarf deer (Cervidae: Mazama sp.) on Pedro Gonzalez Island, Pearl Island Archipelago, Pacific Panama (6.2–5.6 kya)

Abstract

The present study's primary goal is to apply analyses of stable isotopes and tooth micro- and mesowear to the question of dietary change among a mid-Holocene population of small brocket deer (Cervidae: Mazama) in response to anthropogenic alteration of the natural insular vegetation for approximately 450 calendar years (6060-5620 cal yr BP). The brocket deer remains were found in shell-bearing middens on Pedro González in the Pearl Island archipelago. This island is the third largest of many platform or continental islands in Pacific Panama that were periodically affected by rising post-glacial seas during Pleistocene warm periods and became hills in drowned plains during glacial periods, which were extensive on the Pacific side of the isthmus. Our study is based on pre-Columbian Mazama deer remains recovered from excavations in the ancient middens of Pedro González and on modern skeletons of Mazama deer belonging to three United States museum collections. For comparative purposes we added museum specimens of extant white-tailed deer (Odocoileus virginianus) of reduced size from the Florida Keys and Coiba Island (Pacific Panama). Our results show that the diets of 1) present-day white-tailed deer from Coiba and the Florida Keys and 2) the brocket deer (Mazama) still present on San José Island were browsers. On the other hand, as soon as Preceramic people arrived on Pedro Gonzalez ca 6000 cal yr BP, the local brocket deer's diet gradually included more and more abrasive plants in response to changes in vegetation cover related to increasing anthropogenic clearance for cultivation.