Species Delimitation and the Origin of Populations in Island Representatives of Phylica (Rhamnaceae)

Abstract

Abstract. Relationships between the closely related island species of Phylica (Rhamnaceae) and a mainland species, P. paniculata, were elucidated using amplified fragment length polymorphisms (AFLPs). Parsimony, neighbor joining, and principal coordinate (PCO) analyses indicated that each of the species studied is distinct. AFLPs were also useful in elucidating the genetic relationships and possible infraspecific origins of different island populations in the Atlantic and Indian Oceans. Phylica nitida on Réunion is likely to have been derived from P. nitida on Mauritius. Although the sampling on New Amsterdam is not extensive, the data are also consistent with the hypothesis that P. arborea on New Amsterdam was derived from a single colonization of P. arborea from Gough Island. Similarly, the Gough Island population appears to have been derived from a single colonization event, but it is so distinct from those on Tristan da Cunha, that there may have been two separate dispersals to Gough and Tristan/Nightingale from different lines of the mainland progenitor. There is also evidence of a recolonization from Gough to Tristan da Cunha. Thus, Phylica arborea is capable of repeated long distance dispersal, up to 8000 km, even though the fruits and seeds are not of a type normally associated with this phenomenon.

Biogeography of Flowering Plants: A Case Study in Mignonettes (Resedaceae) and Sedges (Carex, Cyperaceae)

“…Plant colonization of Tristan da Cunha Archipelago has been scarcely study, and as far as we know, no similar pattern of colonization (dispersal from Western South America) has been previously described for angiosperms. Nevertheless, long-distance dispersal from Africa to Tristan da Cunha archipelago has been already proposed (Anderson et al, 2001;Richardson et al, 2003). On the other hand, our data support a single colonization of the Mascarene archipelago from Eastern tropical Africa or Madagascar.…”

A single Mid-Pleistocene long-distance dispersal by a bird can explain the extreme bipolar disjunction in crowberries ( Empetrum )

“…Notably, the whimbrel regularly winters in Patagonia, Tierra del Fuego, and the Falklands Islands (42), and whereas the American golden plover winters farther north in South America, it is also occasionally seen in Patagonia and Tierra del Fuego (41). A similar long-distance dispersal by birds was invoked to explain the New Amsterdam-Tristan da Cunha disjunction, separated by a distance of 8,000 km, in Phylica (Rhamnaceae) (43). Although current bird migratory patterns do not necessarily coincide with past migrations, these observations suggest that the bipolar disjunction in crowberries may have originated via bird-mediated long-distance dispersal.…”

Chromosome Number Changes Associated with Speciation in Sedges: a Phylogenetic Study in Carex section Ovales (Cyperaceae) Using AFLP Data

“…Even data analyzed with a correction for nucleotide saturation using the Nei and Li (1979) restric- tion site distance frequently recover phylogenies with long terminal branches and extremely short internal branches (Albertson et al 1999;Richardson et al 2003), suggesting that either comigrating, nonhomologous bands, or inadequate correction for base pair substitution are biasing phylogenetic reconstruction.…”