Ecology, reproductive biology, and in situ conservation of Isoëtes malinverniana

Isoëtes malinverniana is a perennial, submerged lycophyte endemic to the western Po Valley (provinces of Vercelli, Novara, and Pavia). It is classified as Critically Endangered.

In over 15 years of research, we have investigated the ecology, genetics, and reproductive biology of this rare species with the aim of developing targeted conservation measures. Studies, initially conducted in collaboration with the University of Turin, have allowed us to characterize the habitat of I. malinverniana.

It grows anchored to the sandy-muddy bottoms of slow-moving streams, springs, and irrigation canals. It is a highly specialized species that requires oligotrophic, cool, clear, slightly alkaline, and constantly oxygenated water.

Studying the reproductive biology of the species has allowed us to understand that spore germination and sporophyte formation occur primarily and most rapidly at temperatures between 15 and 20°C and only following fertilization of megaspores by microspores. The species is, however, autogamous.

A study of macrobenthic communities at sites currently hosting I. malinverniana, historical sites, and a site where the species has been reintroduced has shown that the former are characterized by low or no biological contamination (very few alien species) and environmental conditions indicative of limited human disturbance. The species has disappeared from canals with the highest percentages of alien macroinvertebrates and clear signs of habitat alteration.

The information gathered over years of research has allowed I. malinveriana to be reintroduced to a site in its native range, albeit only on an experimental basis for now. After more than three years of monitoring, it can be stated that the species can be reintroduced provided water quality is maintained and canal management is consistent with the species’ needs.