CSIRO Publishing blank image blank image blank image blank imageBooksblank image blank image blank image blank imageJournalsblank image blank image blank image blank imageAbout Usblank image blank image blank image blank imageShopping Cartblank image blank image blank image You are here: Journals > Invertebrate Systematics   
Invertebrate Systematics
Journal Banner
  Systematics, phylogeny and biogeography
 
blank image Search
 
blank image blank image
blank image
 
  Advanced Search
   

Journal Home
About the Journal
Editorial Structure
Contacts
Content
Current Issue
Just Accepted
All Issues
Special Issues
Virtual Issues
Sample Issue
For Authors
General Information
Scope
Submit Article
Author Instructions
Open Access
For Referees
Referee Guidelines
Review an Article
Annual Referee Index
For Subscribers
Subscription Prices
Customer Service
Print Publication Dates
Library Recommendation

blue arrow e-Alerts
blank image
Subscribe to our Email Alert or RSS feeds for the latest journal papers.

red arrow Connect with us
blank image
facebook twitter logo LinkedIn

 

Article << Previous     |     Next >>   Contents Vol 16(4)

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

W. F. Ponder and D. J. Colgan

Invertebrate Systematics 16(4) 571 - 582
Published: 05 September 2002

Abstract

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



Full text doi:10.1071/IT01043

© CSIRO 2002

blank image
Subscriber Login
Username:
Password:  

 
PDF (440 KB) $25
 Export Citation
 Print
  
    
Legal & Privacy | Contact Us | Help

CSIRO

© CSIRO 1996-2016