Alicja Konopacka

How to be an invasive gammarid (Amphipoda: Gammaroidea)-comparison of life history traits

About six life history and two ecological traits of gammarid species occurring in Central European waters were compared in order to identify the characters of successful invader. The species were (1) natives: Gammarus fossarum, G. pulex, G. lacustris, G. varsoviensis, G. balcanicus, G. leopoliensis, G. roeselii, and (2) aliens: Gammarus tigrinus, Chaetogammarus ischnus (=Echinogammarus ischnus), Pontogammarus robustoides, Obesogammarus crassus, Dikerogammarus haemobaphes, D. villosus. Generally the alien species were characterised by a combination of large brood size, high partial fecundity, early maturation and by appearance of higher number of generations per year. Also, these species presented higher tolerance towards severe environmental conditions, i.e. elevated salinity and human degradation of the environment. The above features seem to facilitate the colonisation of new areas and competition with native species -- a phenomenon that has been currently observed in various parts of Europe.

Invasions of alien gammarid species and retreat of natives in the Vistula Lagoon (Baltic Sea, Poland)

During the last decades of the twentieth century, the alien gammarid species Gammarus tigrinus, Dikerogammarus haemobaphes, Pontogammarus robustoides and Obesogammarus crassus invaded the lower Vistula River and its deltaic, partly brackish regions. In brackish waters of the Vistula Lagoon the native Atlantic-boreal species Gammarus zaddachi and Gammarus duebeni have been replaced or at least outnumbered by the aliens. As compared to our earlier studies, through the years 1998–2004 we could observe nearly total decline of the native gammarid populations along the coasts of the Lagoon, and overdomination of the North-American G. tigrinus in most places. Possible reasons for the observed phenomena are e.g. increasing pollution and eutrophication of the Lagoon accompanied by competition between the native and the alien species.

Invasive Ponto-Caspian Species in Waters of the Vistula and Oder Basins and the Southern Baltic Sea

The paper gives a historical review as well as recent information on invertebrate and fish species of Ponto-Caspian origin that have invaded the Vistula and Oder drainage systems and the southern Baltic Sea. Notes on the taxonomy of some species are included.

Salinity-related distribution of alien amphipods in rivers provides refugia for native species

There are numerous papers upon the range extension, biology and the impact of alien amphipods upon the local fauna. However, there are no studies concerning the alien versus native species distribution patterns at the catchment scale of river systems. In total 125 sites were sampled: 41 in main rivers constituting the Polish section of the central invasion corridor (Bug, Vistula, Notec with canals, Oder) and 84 in their affluents. The conductivity of large rivers was much higher than in their small affluents. The number of alien species and their abundance was higher at sites with raised conductivity values. The reverse situation was noticed when native amphipods were taken into account. Moreover, large rivers were inhabited by alien fauna, whereas in smaller streams only native species were sampled. The absence of alien amphipods in small rivers may be explained by their ecological preference for a higher conductivity of water. Thus in smaller streams the native fauna is free from the pressure posed by alien amphipods. If not degraded by human activity, small affluents may function as refugia for native amphipod species. Otherwise, elevation of salinity related to improper catchment management or sewage treatment may lead to extinction of such local disjunct population of native amphipods.

THE LIFE HISTORY OF PONTOGAMMARUS ROBUSTOIDES, AN ALIEN AMPHIPOD SPECIES IN POLISH WATERS

Abstract This study has shown that Pontogammarus robustoides has a multivoltine life cycle in central Poland, with three generations per year (spring, summer, and autumn). Reproduction lasts from March/April until October, when the last breeding females are found. The first juveniles appear in May and are present in the population until the end of October. Spring and summer generations mature in a very short time (4–5 weeks). Females born in May and July start breeding at a body length of 8.5 mm, whereas the length of overwintering females breeding in spring ranges 11–18 mm. The number of eggs laid is exponentially correlated with the size of a female (r2= 0.89).

Macrozoobenthos of two Antarctic glacial coves: a comparison with non-disturbed bottom areas

There are only few studies on shallow Antarctic benthic communities associated with habitats affected by intense mineral sedimentation inflow. The analysis of macrofaunal communities associated with two shallow, isolated glacial coves was performed in Admiralty Bay (King George Island) and compared with non-disturbed sites. Multivariate analyses (hierarchical classification, nMDS) clearly separated glacial cove communities (two assemblages) from the sites situated outside both basins (two assemblages). The community influenced by the streamflow of glacial discharge of meltwater situated in the area with sandy–clay–silt sediments had a very low species richness, diversity and abundance. It was dominated by eurytopic, motile deposit feeding polychaetes such as Mesospiomoorei, Tharyxcincinnatus and Leitoscoloploskerguelensis as well as the bivalve Yoldiaeightsi. The second glacial community of the area located at a grater distance from the outlet of the stream was characterized by sandy–clay–silt and clay–silt deposits and showed also a low diversity and species richness. The most abundant here were peracarid crustaceans, with the dominant opportunistic feeder Cheirimedonfemoratus. Community from the non-disturbed area with silty–clay–sand, and silty–sand sediments had higher species richness and diversity. The assemblage of fauna from the sandy bottom has values of those two indexes similar to those found in the disturbed areas.

Life History of Echinogammarus Ischnus (Stebbing, 1898) (Amphipoda) From Artificially Heated Lichenskie Lake (Poland)

The life history of Echinogammarus ischnus was studied in Lichenskie lake, a water basin heated by a big power plant. Results are compared with literature data concerning populations of this species living in its natural habitat.

Necrophagous lysianassoid Amphipoda in the diet of Antarctic tern at King George Island, Antarctica

Amphipod crustaceans constituted 30% of the food biomass from the stomachs of Antarctic tern (Sterna vittata) captured at King George Island in three consecutive seasons. Five species of lysianassoid amphipods occurred in the material: Abyssorchomene plebs, Cheirimedon femoratus, Hippomedon kergueleni, Wuldeckia obesa and Orchomenella rotundifrons. All these amphipods are known as necrophages inhabiting the upper and middle sublittoral of western Antarctic. They are commonly caught in masses in baited traps, but never occur in the littoral zone or in tidal pools. It is suggested that the source of the amphipod diet ofS. vittata are seal or penguin carcasses and dead fish brought by waves to the tidal zone, serving as a bait for necrophagous amphipod crustaceans when submerged in water before stranding on the beach. Received 21 August 1998, accepted 25 January 1999

Obesogammarus crassus (G. O. Sars, 1894) - one more Ponto-Caspian gammarid species in Polish waters

Obesogammarus crassus, a new Ponto-Caspian gammarid species has been recorded in Poland in the deltaic Vistula system. Notes on its origin, places of acclimatization in Europe, as well as probable ways of invasion are presented. Since the majority of alien gammarid species is still poorly recognized, the authors include a simple key and figures allowing the identification of all Ponto-Caspian gammarid crustaceans recently appearing in Polish waters.

Echinogammarus trichiatus (Martynov, 1932) — a new Ponto-Caspian amphipod invader in Poland with remarks on other alien amphipods from the Oder River

Echinogammarus trichiatus (Martynov, 1932), was recorded for the first time in Poland, in the lower Oder River, in September 2012. The species has most probably reached the Oder through the Havel-Oder Canal, being a part of the German inland canal system in which it has been already present since 2006. We found individuals of both sexes, including ovigerous females and juveniles. The structure of its population and its abundance (second dominant gammarid species on the site) suggests that it is well established and, thus, we may expect further invasion of the species into Polish waters. Six other invasive species of amphipods were recorded along the course of the Oder. Four of them, Dikerogammarus villosus, D. haemobaphes, Gammarus tigrinus and Chelicorophium curvispinum, occurred in the entire studied section of the river. Two, Pontogammarus robustoides and Obesogammarus crassus, were found only in the lowest part of the Oder.