Feeding patterns in Eubranchipus grubii (Dybowski 1860) (Branchiopoda: Anostraca) and its potential influence on the phytoplankton communities of vernal pools

Filtration patterns in the fairy shrimp Eubranchipus grubii were analysed under laboratory conditions using water containing phytoplankton from their actual locality in western Poland. After 48 hours of feeding, we compared the structure of algal communities in water samples in treatments with males, females and control. The mean filtration rate for E. grubii was relatively high (14,488 mL h-1) in comparison to other crustacean filter feeders and was higher for females than for males. Fairy shrimps grazed effectively on all 11 dominant phytoplankton taxa and there was no sign of overall preferences with regard to taxon, cell volume, length or shape. Female fairy shrimps removed significantly more cells of three taxa (Cryptomonas erosa, C. ovata and Trachelomonas volvocina). The differences between sexes did not depend on the cell volume or length of particular phytoplankton taxa but were significantly related to their initial abundance, initial biomass and shape. The higher the abundance and biomass of the algal taxa, the more intensively it was grazed by females than by males. Females were also observed to graze more on spherical and elongated cells. In conclusion, our results show E. grubii to be an effective, generalist filter feeder capable of significantly influencing the phytoplankton community of a vernal pool. Possible implications of such grazing pressure are also discussed.

First report of Branchinecta (Anostraca) in seasonal coastal pools in the Araucania region (Puaucho, 39°S, Chile)

To date, he fairy shrimps (Anostraca) of Chilean inland waters have been poorly described. Those that were described mainly belong to the genus Branchinecta, and the reports are primarily restricted to shallow seasonal pools at the northern and southern extremes of Chile. The aim of the present study was to give a first description of Branchinecta rocaensis, reported from ephemeral coastal pools in the Puaucho dunes, situated in the Araucania region. The results of null model analysis revealed first, that species associations are random and that there is niche overlap, while according to the principal component analysis, B. rocaensis was present at sites with low conductivity, low total dissolved solids and low temperature values, but with a high abundance of ostracods. The results obtained would agree with similar observations for Branchinecta habitats in southern Chilean Patagonia.

Fauna of the Pivka Intermittent Lakes

Prispevek opisuje vodno favno presihajočih Pivških jezer. Zaradi presihajočega značaja jezer so bili na tem območju najdeni zanimivi predstavniki nižjih rakov, predvsem iz skupin škrgonožcev (Anostraca), vodnih bolh(Cladocera) ter ceponožcev (Copepoda). Petelinjsko jezero je edini kraj na svetu, kjer še lahko najdemo endemne rakce vrste Chirocephalus croaticus. Vrsti ceponožnih rakov Diaptomus cyaneus in Diacyclops Charon sta relativno pogosti vrsti v Evropi, vendar sta Petelinjsko in Veliko Drskovško jezero v Sloveniji trenutno edini znani nahajališči obeh vrst. Vrste so ogrožene zaradi uničevanja njihovih naravnih habitatov. The present contribution deals with aquatic fauna of the Pivka intermittent lakes. Due to their intermittent character some interesting crustaceans from the groups of fairy shrimps (Anostraca), water fleas (Cladocera) and copepods (Copepoda) are found there. Petelinjsko jezero is the only known location in the world for the endemic species Chirocephalus croaticus. Copepod species Diaptomus cyaneus and Diacyclops charon are relatively abundant in Europe, but Petelinjsko jezero and Veliko Drskovško jezero are the only two locations known in Slovenia for both species. All the species are threatened due to destruction of their natural habitats.