Population dynamics and microhabitat preferences of subterranean amphipods in the flooded forrest Crni jarki

Abstract

Ekološka ograničenja, dinamika veličinsko-dobne i spolne strukture populacije, te reprodukcijska obilježja i značajke životnog ciklusa stigofilnih rakušaca proučavane su u poplavnoj šumi Crni jarki pokraj Đurđevca. Triplikativni uzorci rakova prikupljani su sezonski godinu dana u tri različita vodena mikrostaništa (protočni ksilal s argilalom, stajaći ksilal s argilalom i protočni fital) pomoću bentos mreže (promjera 21 cm i veličine oka 500 um) tijekom razdoblja povišene razine vodonosnika (ožujak, travanj, svibanj i prosinac). Većina rakušaca je prikupljena u protočnom ksilalu s argilalom. Eudominantna vrsta rakušca u svim mikrostaništima je Synurella ambulans (> 73 %), dok je Niphargus valachicus subrecedentna vrsta ( 73 %) in all microhabitats was Synurella ambulans, while the Niphargus valachicus was subrecedent species (< 8 %). The percentage of females reached its peak (100 %) at the end of breeding season in flowing phytal, while the percentage of males peaked (70 %) at the beggining of breeding season in standing xylal with argylal. Juveniles were prevailed during the spring at the end of the breeding season in May, while adult specimens were disappeared from the population in the same month. During the study, live ovigerous females of Synurella ambulans were sampled in order to determine correlation coefficients of the number of eggs with the body length and body mass. Fecundity was positively correlated with body size and negatively correlated with body mass. The egg counts ranged from 11 to 38. The wetland population of Synurella appears to have a one-year life cycle