G Tonczyk

Pollinator diversity and reproductive success of Epipactis helleborine (L.) Crantz (Orchidaceae) in anthropogenic and natural habitats

Background Epipactis helleborine is an Eurasian orchid species which prefers woodland environments but it may also spontaneously and successfully colonise human-made artificial and disturbed habitats such as roadsides, town parks and gardens. It is suggested that orchids colonising anthropogenic habitats are characterised by a specific set of features (e.g., large plant size, fast flower production). However, as it is not well known how pollinator diversity and reproductive success of E. helleborine differs in populations in anthropogenic habitats compared to populations from natural habitats, we wanted to compare pollinator diversity and reproductive success of this orchid species between natural and anthropogenic habitat types. Methods Pollination biology, reproductive success and autogamy in populations of E. helleborine from anthropogenic (roadside) and natural (forest) habitats were compared. Eight populations (four natural and four human-disturbed ones) in two seasons were studied according to height of plants, length of inflorescences, as well as numbers of juvenile shoots, flowering shoots, flowers, and fruits. The number and diversity of insect pollinators were studied in one natural and two human-disturbed populations. Results Reproductive success (the ratio of the number of flowers to the number of fruits) in the populations from anthropogenic habitats was significantly higher than in the natural habitats. Moreover, plants from anthropogenic habitats were larger than those from natural ones. In both types of populations, the main insect pollinators were Syrphidae, Culicidae, Vespidae, Apidae and Formicidae. With respect to the type of pollinators’ mouth-parts, chewing (39%), sponging (34%) and chewing-sucking (20%) pollinators prevailed in anthropogenic habitats. In natural habitats, pollinators with sponging (55%) and chewing mouth-parts (32%) dominated, while chewing-sucking and piercing-sucking insects accounted for 9% and 4% respectively. Discussion We suggest that higher reproductive success of E. helleborine in the populations from anthropogenic habitats than in the populations from natural habitats may result from a higher number of visits by pollinators and their greater species diversity, but also from the larger size of plants growing in such habitats. Moreover, our data clearly show that E. helleborine is an opportunistic species with respect to pollinators, with a wide spectrum of pollinating insects. Summarising, E. helleborine is a rare example of orchid species whose current range is not declining. Its ability to make use of anthropogenically altered habitats has allowed its significant spatial range expansion, and even successful colonisation of North America.

Occurrence of the medicinal leech (Hirudo medicinalis) in birds' nests

Occurrence and breeding of Hirudo medicinalis were recorded in birds’ nests in the fishing ponds and water bodies used extensively by anglers in south-eastern Poland, in 4 of 11 studied bird species (Circus aeruginosus, Fulica atra, Cygnus olor, Chroicocephalus ridibundus). Factors important for the distribution and density of this leech were: nest height, pH of the water and oxygen concentration in the water inside the nests, the body-length of the nesting birds. Our data show that (1) H. medicinalis chooses nests as habitats that are safe in water bodies rich in predators (particularly fish) and provide stable feeding conditions; (2) fishing ponds and other water bodies used extensively by anglers in a landscape modified by human pressure can be an important secondary habitat for the medicinal leech. As the nesting activity of some aquatic birds apparently favors the occurrence of H. medicinalis, active protection of aquatic birds and creating sites appropriate for their breeding may be an indirect way for the conservation of the leech in such areas.

On the occurrence of Cordulegaster boltonii (Donovan, 1807) (Odonata: Cordulegastridae) in the western part of the Lithuanian Lake District (Poland)

The authors analyse three sites of occurrence of Cordulegaster boltonii in the western part of the Lithuanian Lake District (Suwalki Region, north-east Poland). The area is situated within a distance of over 300 km between large agglomerations of the species’ sites in the Tuchola Forest (north Poland) and in south-east Lithuania. Only one historical site is known so far from the study area (from 1911). A small but permanent distribution island probably exists in the study area, although C. boltonii is rare and develops in small populations. A research programme is required to explain the size of the distribution island, its relations to the sites in Lithuania and the status and threats to the species. Aprasomos trys geltonžiedžio žirgelio C. boltonii radavietės vakarinėje Lietuvos ežeryno dalyje (Suvalkai, siaurės rytų Lenkija). Tiriama teritorija yra tarp didelių rūsies radaviecių sankaupų Tucholos miske (siaurės Lenkija) ir pietrycių Lietuvoje, tarp kurių atstumas siekia 300 km. Iki siol sioje teritorij...