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Although most grasses (including cereals) are described as epizoochoric or anemochoric, many authors have shown that grains may be dispersed via the digestive tracts of animals, i.e. are endozoochoric. Cereals have been reported from carnivores' faeces several times; nevertheless, there is no data about the fate (i.e. capacity to germinate) of these grains. The scope of this paper is to focus on the role of medium-sized carnivores as potential secondary dispersers of grains. In 2010–2011, we examined 619 faeces of badgers Meles meles, foxes Vulpes vulpes and martens Martes sp. Faeces were collected every month from June to November in Kampinos National Park (KNP). In seven cases (1.1%) we found 64 grains of a total of two species of cereals: rye, Secale cereale and oats, Avena sativa, in the faeces of red fox and martens, with the red fox samples predominant. Some of the seeds retained the capacity to germinate and to establish seedlings. In two cases, included as accompanying material, feathers of a bird were found, which may suggest secondary dispersal of cereals via carnivores' guts.
It was proposed previously that passive dispersal by migratory aquatic birds explain the widespread distribution of many wetland organisms. Several experimental studies have shown that many widespread wetland plant species can be readily dispersed within the guts of Anatidae. However, it is unclear whether plants with a more restricted distribution are able to disperse via waterbirds. This paper addresses the dispersal ability and germination ecology of the little-known Hungarian milkvetch Astragalus contortuplicatus, which occurs on banks of continental rivers and has a limited and unpredictable distribution. To test whether limited capacity for endozoochory by waterfowl could explain the sporadic appearance of this species, we force-fed ten captive mallards (Anas platyrhynchos) with 100 milkvetch seeds each. Droppings were collected for up to 45 h after feeding. Intact and viable seeds were found in the droppings of each mallard, and altogether 24.7% of seeds fed were recovered intact. The proportion of retrieved seeds that germinated (27.0%) was significantly higher than that of untreated control seeds (0.5%), but significantly lower than that of mechanically scarified seeds (96.0%). Retrieved seeds that germinated developed into healthy mature plants. Given the average flight velocity of mallards, seeds of A. contortuplicatus may travel up to 1600 km inside the digestive tract of migrating individuals. Our results suggest that avian vectors may be more important for the dispersal of rare higher plants (especially those with a hard seed-coat) than hitherto considered. Moreover, they suggest that rarity does not necessarily indicate limited dispersal ability, and may instead be explained by specific habitat requirements.
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