AquaNISInformation system on aquatic non-indigenous and cryptogenic species |
Species | Azolla filiculoides | |
Date of the first record (?) | From 1907 References: Minchin, D. and Baars, J-R. (2020) The water fern Azolla filiculoides Lam. (Azollaceae): from wellestablished to disappeared (H9). Irish Naturalists’ Journal 37 (1): 14-17. Comments: The first known Irish record is from between Little Island and Glounthaune, Co. Cork in 1907 where it was plentiful at that time (Reynolds 2002) Its secondary spread to the wild may be due to flooding of ponds, aquaria releases or following transmissions by birds. Since its first appearance in Ireland it has been widely found within lakes, rivers, canals and ponds and sufficiently abundant to choke some slowmoving watercourses, canals and ponds (Lucey 2003). It is widely distributed in Ireland, in recent years more so than indicated by Preston et al. (2002). An earlier record, in the Lough Derg region, was from the river section draining this lake, consisting of several individuals, was within a marina close to Killaloe (R700735) (Minchin 2005). |
Recipient region (?) | Country: Ireland LME: 24. Celtic-Biscay Shelf LME sub-region: Celtic seas References: Minchin, D. and Baars, J-R. (2020) The water fern Azolla filiculoides Lam. (Azollaceae): from wellestablished to disappeared (H9). Irish Naturalists’ Journal 37 (1): 14-17. Comments: A small unused cut and private harbour on Lough Derg (R751869), east of Mountshannon,Co. Clare, was examined during 12 April 2012, 1 August 2013, 25 May 2014 and 28 April 2016. |
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Source region (?) | Not entered |
Pathway / Vector (?) | Unknown References: Minchin, D. and Baars, J-R. (2020) The water fern Azolla filiculoides Lam. (Azollaceae): from wellestablished to disappeared (H9). Irish Naturalists’ Journal 37 (1): 14-17. Comments: It is unclear as to how A. filiculoides arrived at this site. There was no evidence of aquatic ornamental plants in this region and the fern is unlikely to have been inadvertently planted as a contaminant. A further possibility is an arrival with bird transport from elsewhere. It was clear that birds had been walking over the surface mat in the harbour and so might have similarly been associated with ferns which could have attached to their legs. A further possible explanation is the arrival since May 2014 and before November 2015 of the Frond-feeding Weevil (Stenopelmus rufinasus Gyllenhal, 1836). This beetle is a specialist predator of Azolla species and has been present in Ireland for more than a decade. |
Habitat type (?) | Lake Marina Pond River References: Minchin, D. and Baars, J-R. (2020) The water fern Azolla filiculoides Lam. (Azollaceae): from wellestablished to disappeared (H9). Irish Naturalists’ Journal 37 (1): 14-17. Comments: Since its first appearance in Ireland it has been widely found within lakes, rivers, canals and ponds and sufficiently abundant to choke some slowmoving watercourses, canals and ponds (Lucey 2003). It is widely distributed in Ireland, in recent years more so than indicated by Preston et al. (2002). An earlier record, in the Lough Derg region, was from the river section draining this lake, consisting of several individuals, was within a marina close to Killaloe (R700735) (Minchin 2005) |
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Wave exposure (?) | Not entered | |
Salinity range (?) | Unknown References: Minchin, D. and Baars, J-R. (2020) The water fern Azolla filiculoides Lam. (Azollaceae): from wellestablished to disappeared (H9). Irish Naturalists’ Journal 37 (1): 14-17. |
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Temperature range (?) | Not entered |
Zonation / Substratum (?) | Not entered | |
Reproductive duration (?) | Not entered | |
Reproductive seasonality (?) | Not entered | |
Migration pattern (?) | Not entered |
Population status (?) | Extinct (no recent record) (Moderate level of certainty) References: Minchin, D. and Baars, J-R. (2020) The water fern Azolla filiculoides Lam. (Azollaceae): from wellestablished to disappeared (H9). Irish Naturalists’ Journal 37 (1): 14-17. Comments: Using satellite imagery, the occurrence of the population would appear to have been there from 2009, or before, to 2014/2015. It is suspected that the weevil Stenopelmus rufinasus, which feeds on this fern, was responsible for its complete disappearance. Despite a careful examination of the cut and harbour in April 2016 no ferns were found. |
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Species status (?) | Non-indigenous species |
Created by | Dan Minchin, 2022-04-25 |