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n Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie - Die verspreiding en habitat van Chambardia wahlbergi en Chambardia petersi (Bivalvia: Iridinidae) in Suid-Afrika : oorspronklike navorsing

Volume 31, Issue 1
  • ISSN : 0254-3486
  • E-ISSN: 2222-4173

Abstract

Die verspreiding en habitat van en , soos weerspieël deur data in die databasis van die Nasionale Varswaterslakversameling (NVWSV) word weergegee en bespreek. Alhoewel die verspreiding van hierdie twee spesies grootliks in die Limpopo- en Mpumalangaprovinsie oorvleuel, kom , anders as wat in die literatuur gerapporteer is, ook in die Noordwes- en Vrystaatprovinsie in die wesvloeiende Vaalrivier en in verskeie lokaliteite in die Gautengprovinsie voor. Die meerderheid monsters van beide spesies is in riviere en damme en in watertoestande wat as standhoudend, staande, helder en vars beskryf is, versamel. Multivariansie-analises het temperatuur, hoogte bo seevlak en waterliggame as faktore uitgewys wat betekenisvol tot hul geografiese verspreiding bygedra het. Min is oor die bewaringstatus van hierdie twee spesies bekend, maar die opgedateerde IUCN Rooidata-lys (Seddon 2011) dui albei as nie-bedreig aan. Die meerderheid rekords van beide spesies in die databasis van die NVWSV spruit uit werk tydens die vorige eeu in die Nasionale Krugerwildtuin (NKW). Meer onlangse versamelings deur die outeurs in die NKW dui egter op 'n afname in die aantal plekke van voorkoms, asook die getalle per versamelpunt wat aan die hand doen dat daar tog rede tot kommer oor hul voortbestaan mag wees. Die feit dat besonder groot eksemplare van tot so onlangs soos 2007 meestal toevallig in die Vaalrivier aangetref is, beklemtoon die behoefte om weer omvattende opnames van varswater Mollusca, soortgelyk aan dié van die vorige eeu, van stapel te stuur om die gedokumenteerde verspreiding op te dateer en ook die vordering van eksotiese indringerspesies te moniteer.


Based on the data in the database of the National Freshwater Snail Collection (NFSC), the distribution and habitat of and , are presented and discussed. Although the distribution of these two species overlaps extensively in the Limpopo and Mpumalanga Provinces, contrary to reports in literature, specimens of were also collected in the North West Province and the Free State Province in the west-flowing Vaal River, as well as in Gauteng. The majority of samples of both species were collected in rivers and dams, in water conditions described as perennial, standing, clear and fresh. Multivariate analyses indicated that temperature, altitude and waterbodies played a significant role in the geographical distribution of both species. Although little is known of the conservation status of these species, it is categorised as of least concern in the revised edition of the UCN Red Data List (Seddon 2011). The majority of records of both species in the database of the NFSC date from work done during the previous century in the Kruger National Park (KNP). More recent surveys by the authors in the KNP revealed a decline in the number of positive sites, as well as the number of specimens per site. This data suggest that there might be reason for concern regarding their conservation status. The fact that exceptionally large specimens of were collected, mostly by chance, on several occasions in the west-flowing Vaal River as recently as 2007 emphasises the need to conduct extensive mollusc surveys, as during the previous century, to update the documented geographical distribution and to monitor the progress of exotic invader species.

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/content/aknat/31/1/EJC122141
2012-01-01
2019-10-22

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