The origin of Hydrilla verticillata recently discovered at a South African dam

Madeira, Paul T.; Coetzee, Julie A.; White, Emily; Tipping, Philip W.

doi:10.1016/j.aquabot.2007.04.008

Cited by 52 publications

(65 citation statements)

References 12 publications

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“…The former species is native to Africa, and has been shown to decrease significantly macrophyte diversity at small scales ( quadrats with 1m 2 ) in the Upper Paraná floodplain . The latter species is native to Australia, the Pacific Islands, Asia, and probably Africa (Madeira et al, 2007). Although still rare in lakes of the Upper Paraná River floodplain, H. verticillata became widespread in the Paraná main channel after 2005 (W. T. Souza, unpublished).…”

Section: Discussionmentioning

confidence: 99%

Temporal and spatial patterns of aquatic macrophyte diversity in the Upper Paraná River floodplain

Carvalho

et al. 2009

Braz. J. Biol.

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Although the importance of long-term data has been emphasized by ecologists in recent years, little is known about how communities may change over time. In this study, we describe the general patterns of aquatic macrophyte diversity in the Paraná River floodplain observed during six years of study. Temporal changes in community composition were also evaluated. Data on the presence or absence of aquatic macrophytes were collected between March 2002 and March 2008, in six lakes associated with three rivers. Different analytical strategies were used to evaluate the dynamics of aquatic macrophyte communities between the different systems in the floodplain. The composition of aquatic macrophytes differed among the rivers, mainly with respect to the different vegetation life forms (floating, submersed, emergent and rooted with floating stems). The temporal similarity of species composition during the six years and the beta-diversity index indicated that the month-to-month species turnover was, in general, lower in the connected lakes, which are directly influenced by the river. Probably the water level fluctuation is a selective force that contributes to maintaining diversity or richness. Our findings indicated the importance of abiotic characteristics and connectivity of the lakes in determining macrophyte composition and community stability over a long time frame.

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Section: Discussionmentioning

confidence: 99%

Temporal and spatial patterns of aquatic macrophyte diversity in the Upper Paraná River floodplain

Carvalho

et al. 2009

Braz. J. Biol.

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“…A RAPD (Random Amplified Polymorphic DNA) analysis of SA H. verticillata in comparison to 30 'worldwide' samples indicated that the biotype invading Pongolapoort Dam is monoecious and identical to H. verticillata from Malaysia and Indonesia (Madeira et al 2007). On the basis of this, a leaf-mining fly from Singapore, Hydrellia sp.…”

Section: Introductionmentioning

confidence: 98%

Suitability of a leaf-mining fly, Hydrellia sp., for biological control of the invasive aquatic weed, Hydrilla verticillata in South Africa

Bownes

2014

BioControl

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South Africa developed its first biological control programme for a submerged aquatic weed following the discovery of Hydrilla verticillata (L.f.) Royle (Hydrocharitaceae) in a major tourism dam in 2006. A leaf-mining fly, Hydrellia sp. (Diptera: Ephydridae) from Singapore, originating on a closely related biotype of the weed invading South Africa, was considered a priority candidate agent. Host range was investigated through no-choice and paired-choice larval development trials. ''Host suitability'' trials (multiple generations and performance) were used to further evaluate the potential for non-target host use by the fly. Hydrellia sp. developed on a few closely related species in the Hydrocharitaceae and one species in the Potamogetonaceae. However, pairedchoice tests demonstrated a strong preference for its host plant and the host suitability trials indicated that Hydrellia sp. has very limited potential to establish permanent populations on native aquatic plant species. Hydrellia sp. should therefore be considered safe for release in South Africa.

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“…Hydrilla was introduced into the USA via the aquarium trade (Schmitz et al 1991), and it is likely that this was the mode of introduction into South Africa too. Even though hydrilla has been present in central east Africa for considerable time (Mahler 1979), genetic analysis of South African hydrilla has shown that it is most closely related to hydrilla from Malaysia and Indonesia (Madeira et al 2007), and interestingly, the majority of aquarium plants imported into South Africa come from Singapore, Malaysia (N. Stallard, personal communication).…”

Section: Introductionmentioning

confidence: 98%

Potential spread of the invasive plant Hydrilla verticillata in South Africa based on anthropogenic spread and climate suitability

2008

Self Cite

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Hydrilla verticillata (L.f.) Royle is a submerged aquatic plant native to Asia and Australia that is highly invasive in the USA and was first recorded in South Africa in 2006. It is only known from one locality, Pongolapoort Dam in KwaZulu-Natal Province, but there are fears that it might spread to other sites. The primary vector of spread in the USA is recreational boaters and anglers. A survey at a fishing competition on Pongolapoort Dam showed that anglers travel considerable distances around South Africa (73% of water bodies were [200 km, visited by 68% of the respondents). A Threat Index for freshwater bodies throughout South Africa visited by participants of the competition was calculated showing that dams in the vicinity of the infestation were more at risk from invasion. Further, the potential distribution of the weed based on climatic matching with the region of origin showed that most of the country was suitable for establishment, with the exception of the high-lying interior of the country. Recommendations for reducing the potential spread of hydrilla in South Africa are presented.

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The origin of Hydrilla verticillata recently discovered at a South African dam

Cited by 52 publications

References 12 publications

Temporal and spatial patterns of aquatic macrophyte diversity in the Upper Paraná River floodplain

Temporal and spatial patterns of aquatic macrophyte diversity in the Upper Paraná River floodplain

Suitability of a leaf-mining fly, Hydrellia sp., for biological control of the invasive aquatic weed, Hydrilla verticillata in South Africa

Potential spread of the invasive plant Hydrilla verticillata in South Africa based on anthropogenic spread and climate suitability

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