 Although myrmecochory is by far the most common dispersal method , white @-@ tailed deer have also been shown to disperse the seeds on rare occasions by ingestion and defecation . While ants only move seeds up to about 10 meters , deer have been observed to transport the seeds over 1 kilometer . This helps to explain post @-@ agricultural colonization of forest sites by Trillium grandiflorum , as well as long distance gene flow which has been detected in other studies . Furthermore , it helps resolve what has been called " Reid 's paradox " , which states that migration during glaciation events must have been impossible for plants with dispersal rates under several hundred meters per year , such as Trillium grandiflorum . Thus occasional long distance dispersal events , such as by deer , probably helped save this and other species with otherwise short distance dispersal ability from extinction during the glaciations of the ice ages . Furthermore , nested clade analysis of cpDNA haplotypes has shown that Trillium grandiflorum is likely to have persisted through the last glacial period in two sites of refuge in the southeastern United States and that long distance dispersal was responsible for the post @-@ glacial recolonization of northern areas . 
