Disjunct distribution

Some years ago, Breckon and Barbour (1974) published a review of beach vegetation for the North American Pacihc Coast that contains detailed information on a wide variety of strand taxa. A number of taxa discussed in their work have disjunct distributions, involving other continental beaches suggesting other taxa worthy of detailed phytogeographic study. 

The bryophyte literature provides many examples of disjunct distributions often involving sites that defy easy explanations for their existence. Nonetheless, they... 

Krameria L. consists of 15 (Mabberley, 1997, p. 383) or about 17 species (Simpson et al., 1979), with a disjunct distribution between central United States (Kansas) and northern Argentina to Chile. Two reports of lipids from flower glands of several species representing both regions have been published, the North American members by Seigler et al. 

Wen, J. 1999. Evolution of eastern Asian and eastern North American disjunct distributions in flowering plants. Ann. Rev. Ecol. Syst. 30 421-455. 

Yokoyama J, Suzuki M, Iwatsuki K, Hasebe M (2000) Molecular Phylogeny of Coriaria with Special Emphasis on the Disjunct Distribution. Mol Phylogen Evol 14 11 Corbella A, Gariboldi P, Jommi G, Scolastico C (1969) Biosynthesis of Tutin. J Chem Soc, Chem Conunun 634—635... 

PaUce, Z., Printzen, C. (2004). Genetic variabiUty in tropical and temperate populations of Trapeliopsis glaucolepidea evidence against long range dispersal in a lichen with disjunct distribution. Mycotaxon 90, 43-54. 

Disjunct distributions are known for numerous lichens. For example, several disjunct lichen fungi are known from the boreal zone of western Fennoscandia, Newfoundland and the Pacific Northwest region of North America notable examples of this distribution pattern are Cavernidaria hidtenii, Erioderma pedicellatum and Loharia hallii (Ahlner, 1948 Bjerke, 2003 Otte et al., 2005). 

Otdlora, M.A.G., Martinez, 1., Aragdn, G., Molina, M.C. (2010). Phylogeography and divergence date estimates of a lichen species complex with a disjunct distribution pattern. American Journal of Botany 97, 216-223. 

Certain intriguing disjunct distributions that are difficult to interpret under a historic and geologic perspective provide support for the long-distance dispersal hypothesis. Perhaps the best examples are the bipolar disjunctions, distributions that include boreal or temperate regions in both hemispheres but with an absence from the landmasses in between. There are 18 bryophytes species in Antarctica that are known to have this type of distribution (Ochyra et al., 2008). In most cases, species with bipolar disjunctions have a predominantly Holarctic distribution and... 

Heinrichs, J., Hentschel, J., Feldberg, K., Bombosch, A., Schneider, H. (2009a). Phylogenetic biogeography and taxonomy of disjunctly distributed... 

Another group of species demonstrated a disjunct distribution pattern involving areas of caatinga forest in central-southern Bahia as well as areas ranging from northern Parafba, southern Ceara and north-eastern Piaul. Habitat has been poorly recorded on material coming from these last two states, but some of these species seem to occur in the piedmont of residual landforms. Some examples of this type of distribution are seen with Hymenaea martiana, Calliandra spinosa Ducke and Chloroleucon foliolosum. 

The model proposed here combines the present-day geomorphological configuration of the extensive and mostly continuous crystalline surface with discontinuous areas of sedimentary surfaces. As such, it would also provide an explanation of the disjunct distribution of the species inhabiting sandy areas, as being a consequence of the events promoting vicariance within a formerly... 

FIGURE 10.7 Disjunct distribution of/M ffcwtoca n a, an essentially cerrado species occurring as a distinct species at the eastern end of the Bolivian dry valley system. 

Ever since a seminal paper by Prado and Gibbs (1993), there has been considerable interest in the disjunct distribution of certain dry forest species in tropical America (e.g. Pennington et al., 2000). It has been argued that these represent relict populations of widespread dry forest in the Neotropics during the late Pleistocene. Some support for this thesis is provided by the phytogeography of species in the three families under discussion here. 

It is interesting that most species in these families that show a disjunct distribution, conforming loosely to the Pleistocenic arc, are essentially cerrado species rather than species of seasonally dry tropical forests. It is also in species such as Justicia aequilabris or genera such as Hemipogon where the best evidence for ongoing evolution of species can be discerned. However, until phylogenetic... 

FIGURE 10.10 Disjunct distribution of Justicia aequilabris, a dry forest species of central Brazil occurring in the Rio Grande basin as an endemic subspecies, riograndina. 

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