engleski

Life history traits of the endangered endemic amphipod Echinogammarus cari (Crustacea, Gammaridae) from the Dinaric karst

The life history of the endemic amphipod Echinogammarus cari, endangered by damming, was studied at a site on the Gojačka Dobra River which was flooded after closure of a large dam (D5) and at a site in an intact tributary (B2). Four replicate samples in moss microhabitats were collected over twelve months. Site B2 had a lower range and mean water temperature (10.8°C) and higher concentration of calcium ions. The population sampled at this site showed continuous reproduction, very high densities and a cohort life span of 6–7 months. Site D5 showed higher summer temperatures (max. recorded: 21.0°C), and the population at this site had a reproductive resting stage in September and October, a lower density and a cohort life span of 7–12 months. Growth of cohorts was faster during the colder period of the year at both sites, while higher summer temperatures at D5 inhibited growth. These results show that the proximate cause of the restricted distribution of the species is adaptation to relatively colder conditions with higher calcium content. The presented results provide a better understanding of the damming impact on the species and will contribute to the development of conservation plans to ensure its future survival.

Echinogammarus; reproduction; fecundity; environmental factors

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