Community structure of aquatic insects in the karstic Jadro River in Croatia.

Biljana Rađa,Mate Šantić,Henry Hagedorn

doi:10.1093/jis/14.1.54

Abstract

This study focused on the aquatic insect community in the longitudinal gradient and temporal scales of the Jadro River. The river was sampled for a period of ten years (2000– 2010), four times per year through the various seasons, along the river course. Sampling stations were selected in the upper, middle, and downstream parts of the river. A total of 21,852 specimens of aquatic insects belonging to six orders were obtained. The species determination confirmed 27 different species in the river. The data were analyzed by the multivariate methodologies of correspondence analysis and cluster analysis (unweighted pair group method with arithmetic mean) using the similarity index of Morosita for all ten years. Canonical correspondence analysis was applied to the data to check which of the mesured physicochemical variables significantly explained community variation. According to those data, significant variables for the upper station were water temperature and dissolved oxygen, and chlorides was the significant variable for the lower stations.

Highlights

Observing the community structure of the aquatic organisms in streams and rivers is a very usefull tool for biological analysis of streams and rivers because those organisms have specific responses to changes in environment and physicochemical factors
From that point of view, karst rivers in Croatia represent unique habitats defined with specific physico-chemical water parameters that influence the faunal composition of those rivers (Rađa and Puljas 2010)
The Jadro River is a part of the Cetina catchment area together with the karstic rivers Ruda, Grab, and Žrnovnica (Bonacci 1978)

Summary

Introduction

Observing the community structure of the aquatic organisms in streams and rivers is a very usefull tool for biological analysis of streams and rivers because those organisms have specific responses to changes in environment and physicochemical factors. Those changes are relatively easy to measure and interpret (Karr and Chu 1999). Karst is defined as a terrain, generally underlain by limestone or dolomite, in which the topography is formed by dissolving rock, and which is characterised by sinkholes, sinking streams, closed depressions, subterranean drainage, and caves (Field 2002). The Jadro River is a typicall Mediterranean karstic river, as Munne and Pratt (2004) define in their work

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Conclusion