Occurrence of Hirudinea species in a post urban reach of a Patagonian mountain stream

Abstract

ABSTRACT. Temporal (May 2005 to February 2006 and habitat distribution (pools and riffles) of Hirudinea species was analyzed at a post urban reach from Esquel stream (Chubut province, Patagonia, Argentina). Site was located 5.7 km downstream a Waste Treatment Plant. Mean values of nutrients: ammonia, nitrates and soluble reactive phosphate, as well water conductivity, turbidity and total suspended solids indicated physical and organic pollution. Leeches assemblage was composed by the glossiphonids: Helobdella scutifera Blanchard, 1900, H. michaelseni (Blanchard, 1900, H. simplex (Moore, 1911), Helobdella sp., H. hyalina Ringuelet, 1942, H. obscura Ringuelet, 1942 and the semiscolecid Patagoniobdella variabilis (Blanchard, 1900). From these H. hyalina and H. obscura are new records for Chubut province. Helobdella hyalina (810 ind.m -2 ) and H. simplex (465 ind. m -2 ) clearly dominated the assemblage at the reach. Only H. simplex displayed a spatial preference being significantly more abundant in pools than in riffle habitats (p<0.001). Species recruitment occurred mostly at September, December and March when juveniles were very abundant. Although several species of Helobdella were able to live in the disturbed section of the stream, only H. simplex and H. hyalina sustained large populations at the site and can be considered as tolerant to organic enrichment. This information is valuable to future studies on stream condition assessment in mountainous areas in Patagonia, and in other areas in which these species are present.

Assessing the sensitivity of leeches as indicators of water quality

“…The richness of leeches decreases in relation to organic pollution (Gullo and Darrigran, 1991). However, some species, as H. simplex, seem tolerant to the organic enrichment (Miserendino and Gullo, 2014). Our result agreed with previous observations, H. michaelseni and H. simplex showed a very long tolerance phase for BOD 5 occurring even in high concentrations of this variable.…”

“…Chyla, 1998;Skriver et al, 2000;Pizzolón and Miserendino, 2001). However, information about leeches' relationships with habitat and water quality have been published scarcely (Kubová and Schenková, 2014;Kazancı et al, 2014;Miserendino and Gullo, 2014).…”

Emergent contaminants in spring rivers and their relation to the benthic macroinvertebrates

“…The leeches represented 57.4% of this total, and 55.7% of them belonged to the genus Helobdella (Hirudinea: Glossiphoniidae). Degraded environments usually exhibit low diversity of hirudineas allied to high abundances, since they are considered highly tolerant organisms, occurring in coastal zones of lakes and rivers, and even in urban rivers considerably degraded (Miserendino & Gullo, 2014;Alba-Tercedor et al, 2017;Cortelezzi et al, 2018). Although the occurrence of a high number of species may indicate a preserved aquatic environment, since the richness of leeches decreases in relation to organic pollution (Gullo & Darrigran, 1991;Cortelezzi et al, 2018), the number of species found, nine in total, corresponds to a single genus (Helobdella) considered resistant to environmental disturbance (Koperski, 2017;Cortelezzi et al, 2018), which suggests that the environment started to be affected.…”

Application of Ecological Indices using Macroinvertebrate Assemblages in Relation to Aquaculture Activities in Rawang Sub-basin, Selangor River, Malaysia

“…Glossiphoniidae (some Helobdella sp.) can be considered as tolerant of physical water quality factors such as turbidity and TSS (Miserendino & Gullo, 2014).…”