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Results of the first documented reintroduction of the endangered endemic quillwort Isoetes malinverniana are presented 1 year after transplanting. This represents the most complete report of a quillwort translocation globally. A new population of I. malinverniana was established in a protected area in Lombardy (northern Italy) after several years of investigation of the ecology, biology and genetics of this species. The selected site was restored before the trial release in March 2016 of 20 individuals of the target species. Although modelling for the selection of suitable release sites for the target species indicated that the selected site was not suitable for the species, I. malinverniana exhibited a survival of 60% 1 year after reintroduction. This trial indicates that with very rare species, experimental trialling of a few individuals can test the feasibility of translocation at a larger scale. Although the model was constructed using a wide variety of ecological and phenological parameters, it was unreliable because of intrinsically low statistical power, which is a limitation of modelling associated with very rare species. Although mature spores were dispersed in autumn 2016, sporelings have not yet been observed. Ultimately, reintroduction of I. malinverniana will rely on the evidence of self-recruitment; however, this translocation effort promoted understanding of ecological tolerance and facilitated focused conservation management. For instance, a protocol for in vitro reproduction of the species was successfully developed, resulting in long-term survival of ex situ collections that exist in two botanical gardens in Pavia and Turin. Considering that many isoetid species are threatened worldwide, the techniques applied here may have broad applicability to other endangered species.

Conservation of Leucojum aestivum, a wetland-dependent species distributed in Europe and west Asia, should aim to reduce the fragmentation of wild stands, through the establishment of new populations. However, density-dependent dynamics occur in L. a estivum. For instance, fruit set and seed set increase with increasing plant density. In this study, we evaluate the effect of plant density on translocation success of two recently established populations of L. a estivum. Twenty-six populations of L. a estivum were investigated in northern Italy to find out differences in population traits (size, density, age structure, and reproductive performance) between populations from different habitats. Data obtained were used to establish two new populations of the species differing for population density (high H, mirroring the typical plant density of a wild population in Salix alba woods and low L, in which plant density was halved compared to H), to evaluate the role of density-dependent dynamics on the translocation success. 4 years after the translocation, H produced seedlings, while L did not. Moreover, H produced a significantly higher number of fruits per fruiting plant and higher fruit set. Seed set was also greater in H than in L, while mortality was greater in L than in H, but differences were not significant. Our results suggest that population density is an important factor to account for in newly established populations, especially in those species showing density-dependent population dynamics. Moreover, the imitation of successful within-population dynamics occurring in natural stable populations may increase the translocation success.