Autecology and distribution of Isoetes longissimum in Europe

Abstract

Isoetes longissimum is a rare aquatic pteridophyte known only from the northwest Spanish region of Galicia and from Algeria. We mapped the distribution of this species in Galicia, and investigated the relationship between its presence or absence and water quality variables. I. longissimum is present in sixteen 10 times 10 km grid squares in Galicia, largely in the western central part of the region. Within Galicia, I. longissimum shows a significant preference for sites with low sulphate, ammonium and phosphate concentrations.

Isoetes fluitans sp. nov.: the identity of Spanish plants of ‘I. longissimum’

“…In contrast, the Spanish populations are clearly active in summer, and the fronds persist throughout the year. In addition, these plants are strictly aquatic, growing exclusively in permanent watercourses (Romero & Amigo, 1995).…”

“…It is of uncertain rank, difficult to distinguish from I. velata , and there is scant herbarium material available. However, it was cited at various European locations in early publications (see Lange, 1860–65; Willkom & Lange, 1870), and has likewise been cited from the north‐west Iberian Peninsula more recently (Prada, 1983, 1986; Jermy & Akeroyd, 1993; Romero & Amigo, 1995).…”

“…Spores develop in summer. Aquatic plant growing in rivers in north‐west Iberia (Romero & Amigo, 1995), rooted in the river‐bed. Polyploid, 2 n = 44 (Prada, 1983).…”

A cost‐effective model for preliminary site evaluation for the reintroduction of a threatened quillwort

“…in preparation), thus the relationships between EC, pH, soil pH, nitrogen, organic carbon, P 2 O 5 , K 2 O, and water CaCO 3 , NO 3 ‐ , PO 4 3‐ , Cl and NH 4 + , were tested by using Spearman correlations. Finally, the reliability of the models was tested using EC and pH values available from the literature for other species of Isoëtes (Rørslett and Brettum, ; Romero and Amigo, ; Wen et al , ; Free et al , ). Unfortunately, most of the published data referred to sites supporting growing populations and only in one case were data for an extinct site of I. sinensis found (Wen et al , ).…”