Isoetes malinverniana 

Scope: Global, Europe & Mediterranean
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Lycopodiopsida IsoËtales IsoËtaceae

Scientific Name: Isoetes malinverniana Ces. & De Not.
Common Name(s):
English Piedmont Quillwort
Calamaria malinverniana (Ces. & De Not.) Kuntze
Isoëtes malinverniana Ces. & De Not.
Taxonomic Source(s): Christenhusz, M. and Raab-Straube, E. von. 2013. Polypodiopsida. Euro+Med Plantbase - the information resource for Euro-Mediterranean plant diversity. (Accessed: 2015).
Taxonomic Notes:

There are no significant taxonomic issues associated with this name.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered A2c ver 3.1
Year Published: 2017
Date Assessed: 2016-06-01
Assessor(s): Christenhusz, M., Bento Elias, R., Dyer, R., Ivanenko, Y., Rouhan, G., Rumsey, F. & Väre, H.
Reviewer(s): Abeli, T., García, M., Lansdown, R.V. & Troìa, A.
Contributor(s): Barni, E., Gentili, R., Orsenigo, S., Rossi, G. & Siniscalco, C.
This Italian endemic plant has suffered from a decline of 88% in its extent of occurrence (EOO) in the last ten years. Therefore the population is estimated to have declined more than 80% during the last three-generation period (over 30 years) and it is thus assessed as Critically Endangered. The occurrence of this species in irrigation canals and rice fields leads to population declines due to water pollution and grading of the canals in the dry season. The causes for the decline continue and appropriate conservation measures are urgently needed but not yet in place. However, subpopulations are continuously monitored and being reinforced. Plants grown from spores become fertile after two or three years.
Previously published Red List assessments:

Geographic Range [top]

Range Description:

This plant is endemic to the Piedmont and western Lombardy in northern Italy, its extent of occurrence (EOO) is somewhere between 305-7,593 km², but its area of occupancy (AOO) within this range is 36 km². 

A comparison of the historic with the current range revealed a decline of 88% in the last ten years. There was a particularly strong reduction in 2009 when four localities near Pavia were destroyed and a similar number of localities has disappeared in Piedmont in the last decade (Barni et al. 2013).

Countries occurrence:
Italy (Italy (mainland))
Additional data:
Estimated area of occupancy (AOO) - km2:36
Lower elevation limit (metres):60
Upper elevation limit (metres):350
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Surveys of the research team of the University of Pavia and Turin counted 12 growing sites in 2009, most of them (10) occurring in a small area around the town of Arborio (Piedmont). Two small sites have been found close to Vigevano (Lombardy) and Novara (Piedmont) (Barni et al. 2010). Genetic analysis revealed that I. malinverniana has a low between-subpopulation genetic diversity and a moderate level of within-subpopulation genetic variability (Gentili et al. 2010).

The generation length of this species is unknown but likely to be longer than 10 years. The population trend is fluctuating, but in the longer term decreasing. The population is estimated to have declined more than 80% during the last three generations.

A new subpopulation has been established by the University of Pavia in the Ticino Natural Park near Vigevano, within the historic range of the species. This subpopulation counts on 25 individuals and represents the first successful reintroduction trial.

Current Population Trend:Decreasing
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:Isoetes malinverniana is an aquatic plant found in clear, fresh and rapidly flowing spring water and in irrigation ditches of rice fields between 60 and 350 m elevation. It is adapted to survive dry periods and can withstand low temperatures. The plant prefers loamy soils with a high sand content (Tutin et al. 1964, Prelli 2001).
Generation Length (years):10

Use and Trade [top]

Use and Trade:

Isoetes malinverniana is sometimes mentioned in aquarium literature as an item for aquatic plant collectors, but it is not available in the commercial trade. This mentioning in the literature may initiate illegal collecting from the wild. 

Threats [top]

Major Threat(s): The main threats for I. malinverniana come from a change in the cultivation of rice, as a consequence of inappropriate irrigation channel management and eutrophication of the water. A threat directly affecting the species in some subpopulations is mechanical bank adjustment and mechanical brush that remove the channel sediments in the dry season, affecting the survival of adult plants, sporeling establishment and the formation of a spore bank in the soil. Manual brush seems to have a positive effect as it removes other faster-growing species that can compete with I. malinverninana for light and nutrients (Amosso 2010, Barni et al. 2010, Abeli et al. 2012), whereas plants of Isoetes are not affected. Increased nutrient concentration into the water indirectly affects I. malinverniana through the competition with other aquatic macrophytes that compete for light and nutrients (Amosso 2010, Barni et al. 2010). On the other hand, artificial channels dug in the past for rice field water supply increased the surface of suitable habitat available for the species. Thus, traditional rice cultivation is of primary importance for the species survival, impacting it both positively and negatively.

Conservation Actions [top]

Conservation Actions: This species is listed on Annex II of the Habitats Directive and under Appendix I of the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention). It is listed in Annex C1 (Species of native flora protected in a stringent way) of the regional law in Lombardy, L.R. 10/2008. Despite this, its aquatic habitat is much threatened by water pollution, poor land management, industrial development, building and road works, and especially by extraction of sediment from water bodies where this species occurs. The ecology, reproductive biology and genetics of the species have been studied by the University of Pavia, Milano-Bicocca and Turin. It is present in protected areas throughout its range.

A few plants of I. malinverniana are currently cultivated at the Botanical Garden of the University of Pavia and at the University of Turin but ex-situ conservation of the species could be increased. Appropriate management of its sites such as replacing mechanical with manual brushing and managing nutrient levels are needed. Furthermore, a species recovery and reintroduction programmes are now in place. Annual monitoring of the subpopulations and habitat trends are carried out.

Citation: Christenhusz, M., Bento Elias, R., Dyer, R., Ivanenko, Y., Rouhan, G., Rumsey, F. & Väre, H. 2017. Isoetes malinverniana. The IUCN Red List of Threatened Species 2017: e.T162124A85431493. . Downloaded on 19 August 2018.
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