Seed Dispersal by Kerama Deer (Cervus nippon keramae) on Aka Island, the Ryukyu Archipelago, Japan¹

Abstract

Endozoochorous seed dispersal by kerama deer (Cervus nippon keramae) was investigated at four sites on Aka Island, the Ryukyu Archipelago, Japan. Kerama deer feces contained seeds of 35 plant species. Most of the germinated seeds were small (1.3 ± 0.18 mm) and had a hard coat, comparable to the germinated seeds in several other studies of endozoochorous seed dispersal by herbivores. Both the numbers and species compositions of seeds differed among the four sites, reflecting differences in the food available to kerama deer among habitats. Although many graminoid seeds were found in the two open habitats (Sites A and B) and in the adjoining forest habitat (Site C), woody plant seeds dispersed endozoochorously by birds and mammals were dominant in the forest (Site D), away from the marsh. Although a majority of the graminoid species was growing in open habitats such as the marsh and open fields, few were growing in the forest. Therefore, the kerama deer spread many open-habitat graminoid seeds to the open and forest habitats. If a high density of kerama deer persists for a long time and gaps in forests are created by browsing kerama deer or by other means, graminoid species may spread substantially on Aka Island. Therefore, it is possible that seed dispersal by forest deer contributes to the expansion of grasslands.

Seed Dispersal Distances and Plant Migration Potential in Tropical East Asia

“…All the region's fruits bats, except the subcanopy species mentioned above, are probably in one or both of these categories, with the potential to disperse tiny swallowed seeds over several kilometers (see also the next category). Deer disperse seeds both by regurgitation of large, hard seeds (e.g., Prasad et al 2006) and defecation of small ones, with the latter route of particular interest because of the potential for dispersal of small-seeded understory plants over much longer distances than their 'normal' dispersal mode (Myers et al 2004, Yamashiro & Yamashiro 2006. Similar maxima have also been estimated for the largest herbivores, including tapirs (Williams 1978), elephants (Campos-Arceiz et al 2008), orangutans (Singleton & van Schaik 2001), and probably deer (Muntiacus, Rusa), although the only reported maximum for deer in TEA was o1 km (Chanthorn & Brockelman 2008).…”

Altered Ecologies: Fire, climate and human influence on terrestrial landscapes: Terra Australis 32

“…Large deer disperse seeds both by regurgitation of large, hard seeds from fleshy fruits (e.g. Prasad et al 2006) and by defecation of small ones, with some of the latter swallowed incidentally during consumption of foliage (Myers et al 2004;Yamashiro and Yamashiro 2006). Pigs and bovids disperse small seeds in the same way as deer, but their role, if any, in dispersing larger seeds is not known.…”

Effects of dung beetles on seedling emergence from herbaceous seeds in the dung of sika deer (Cervus nippon) in a temperate Japanese grassland ecosystem

“…Seeds ingested by large herbivorous mammals may be affected both physically and chemically as they pass through the digestive tract, so small, hard seeds have higher survival rates (Gardener et al 1993;Gill and Beardall 2001;Myers et al 2004;Mouissie et al 2005). For example, the majority (75-90% of the species) of seeds dispersed by deer species were <3 mm long (Myers et al 2004;Yamashiro and Yamashiro 2006). However, in a germination experiment conducted with herbaceous seeds in sika deer dung, germination rates of smaller seeds were significantly lower in intact dung than in fragmented dung (Ishikawa 2010).…”