What makes a narrow-range taxon? Insights from Australian freshwater snails.

摘要: A combination of intrinsic and extrinsic factors, such as dispersal capabilities or opportunities, habitat preferences, life history attributes, physiological availability, biotic abiotic interactions historical determine not only the geographic distribution a taxon, but its propensity for population differentiation speciation. Freshwater hydrobiid snails have little ability to disperse outside their immediate opportunities accidental are limited. Long-term permanency is critical existence many taxa highly dependent on local hydrological conditions and/or rainfall, water chemistry, geology structure non-aquatic environment. Dispersal success apparently related habitat, including factors size riparian vegetation canopy, well proximity other populations behaviour snails. Speciation patterns complex clusters narrow-range generally understood. Allozyme data four genetically distinct were analysed at Wilsons Promontory, Victoria. Two these showed high levels largely concordant with location, suggesting long in situ evolution. The two much less divergence between populations, relatively recent dispersal. Narrow-range diversity concentrated parts south-eastern Australia, Tasmania, artesian springs associated Great Artesian Basin. These areas unfortunately coincide some least protected areas. Human-induced changes will undoubtedly threaten viability localised populations. loss fragmentation suitable may caused extinction be contributing accelerated