African savanna elephants and their vegetation associations in the Cape Region, South Africa: Opal phytoliths from dental calculus on prehistoric, historic and reserve elephants

This study tests the association between opal phytoliths in dental calculus on modern, historic, and prehistoric specimens of Loxodonta africana (African savanna elephant) with their local and regional vegetation. The modern samples were obtained from dental remains from deceased animals at the Addo Elephant National Park (Eastern Cape Province) and the Pilanesberg National Park & Game Reserve (Northwest Province) in the Republic of South Africa. The historic and prehistoric specimens, presumed to be free-roaming elephants, were sampled from museum collections in the Eastern Cape and Western Cape Provinces. In addition to comparing phytolith assemblages in dental calculus with those of the main vegetation associations, this study assesses the phytolith assemblage differences between free-roaming and park elephants. The results show that: (1) the phytolith assemblages in dental calculus of park elephants show little variation among individual specimens and close resemblance to phytolith assemblages of soils inside their areas of confinement; (2) the free-roaming specimens have a much higher diversity of phytolith morphotypes than those in parks and reserves, exhibiting sometimes typical signatures of more than one biome; (3) free-roaming Cape elephants from fynbos areas have significant amounts of Restionaceae phytoliths, which suggests that grazing on restios in grass-poor fynbos types was important; (4) short saddles, typical of Chloridoideae grasses, are always the most abundant short-cell morphotypes in dental samples, even in areas where other grass subfamilies dominate, and (5) with some limitations, the study of phytoliths in herbivore dental calculus has a high, largely unexplored, potential in paleoecology and conservation ecology. (C) 2017 Elsevier Ltd and INQUA. All rights reserved.