Dry-mesic upland forest, bluff and ravine forest, floodplain forest; contains relictual
The presence of this species in a deep mesophytic ravine harboring other relictual
species reinforces data from vascular-plant studies documenting these habitats in the Niobrara River Valley as a postglacial corridor and refugium of considerable phytogeographic significance (Kaul et al.
The range of the so-called relictual
intergrades between the lizards Sceloporus undulatus garmani and S.
Pleopeltis gyroflexa was once widespread in northern South America (in areas not occupied by Amazon forest), and the two populations now represent relictual
populations generated by vicariance; 2.
mattarega in central Arizona may be relictual
, having been isolated since the drier Holocene period began ca.
It is not obvious whether the above species have maintained relictual
populations in this region or whether colonization has occurred more recently.
Nueva especie de serpiente (Reptilla: Colubridae: Liophis) de un bosque tropical relictual
en el Estado Barinas, Venezuela.
Its tramp status as well as that of others in the genus renders 'original' or natural distributional limits difficult to interpret, with disjunct populations of this species and others easily assigned to human transport (Trager 1991), rather than to relictual
or other possible interpretations.
In addition, several of these mountain ranges are separated by wide stretches of low elevation habitats which appear to be impermeable barriers between the known populations and suggest a relictual
presence for the species.
An insect fauna unique to Nebraska or, for that matter, the Great Plains does not exist although a few relictual
or isolated taxa may occasionally be found there.
guttata now have isolated, northern relictual
populations, none of which have evolved taxonomic distinction.
Comparative genetic study confirms exceptionally low genetic variation in the ancient and endangered relictual
conifer, Wollemia nobilis (Araucariaceae).
eremicus apparently has survived as a relictual
population in riparian and artificially irrigated habitats along the Colorado River in southwestern Arizona and southeastern California.
Pellaea ovata can be added here as another example of a relictual
element, because its distribution is coincident with this dry arc, especially along the line of latitudes between 15[degrees]-28[degrees]S, between Bolivia (Chuquisaca, La Paz, Tarija, Cochabamba), Argentina (Catamarca, Salta and Tucuman), and Brazil (Silo Paulo).
The probable relictual
nature of this species needs further investigation, but montane characteristics clearly limit the distributional potential of nuthatch species.