AbstractGreenhouses form favourable conditions for establishing stable populations of native as well as invasive alien microinvertebrates. Investigations of palm houses have a long tradition and native, alien and new species for science have been found in many of them. The examined pond and some microreservoirs in Bromeliaceae and Agavoideae in Pozna´n Palm House (Poland) sampled in 2012, appeared to contain representatives of Rotifera (64 species), Copepoda (2 species), Polychaeta, Acari and Insecta larvae. The most abundant Rotifera species were: Anuraeopsis fissa Gosse, 1851, Ascomorpha ecaudis Perty 1850, Euchlanis dilatata Ehrenberg, 1832, Pompholyx sulcata Hudson, 1885 and Trichocerca rousseleti Voight, 1902. Moreover, rotifers considered to be rare in Poland, i.e., Asplanchna herricki De Guerne, 1888, Collotheca pelagica Rousselet, 1893, Colurella sulcata Stenroos, 1898, Gastropus minor Rousselet, 1892 were also detected in Pozna´n Palm House. Two recorded Copepoda species were Phyllognathopus viguieri (Maupas, 1892) found in agave microreservoirs and Mesocyclops leuckarti (Claus, 1857) found in reservoir with aquatic plants. For biodiversity evaluation of rotifers Margalef’s and Shannon-Wiener’s indexes were used and in order to determine species richness the Simpson index was calculated. Additionally, a complete list of all aquatic invertebrates is presented, i.e., Plathelmintes (11 species), Nemeretea (2 species), Oligochatea (13 taxa), Polychaeta (7 species), Gastrotricha (13 taxa) and Copepoda (1 species) previously recorded in Pozna´n Palm House. To sum up, Palm houses create a convenient habitat for a prevalence of native and introduced invertebrates and are a putative source of alien species, possibly facilitating their release to the environment.
Increases in local richness (α-diversity) following invasion are offset by biotic homogenization in a biodiversity hotspot
