Over enige Littorelletea-gemeenschappen, in het bijzonder in Twente

In Twente (province of Overijssel) the best developed Littorelletea communities were formerly found in moorland pools. Nowadays the Littorelletea vegetations have become impoverished and in many cases have disappeared completely from the pools. In recent years a number of Littorelletea vegetations has been found in closed country-seats (both in small and somewhat larger waters) and in habitats (pools and ditches) created by road construction. The author distinguishes six associations from Twente (table 5): A Isoeto-Lobelietum; B Eleocharetum acicularis; C Deschampsio-Eleocharetum multicaulis (ass. nov.); D Scirpetum fluitantis; E Pilularietum globuliferae; F Sparganietum minimi. The former three associations (A, B and C) are classified into the alliance Littorellion uniflorae consisting of communities in which isoetids are characteristic. The remaining three associations (D, E and F) are classified into the Helodo-Sparganion. The communities belonging to this alliance consist chiefly of amphiphytes which usually develop a floating or a drifting form on inundated places. In this syntaxonomical division of the Littorelletea the association Eleocharetum multicaulis has been split into the Deschampsio-Eleocharetum multicaulis and the Scirpetum fluitantis. The preservation of the Littorelletea is best assured by the protection of extant vegetations and the creation (for instance by excavation) of new habitats.