Rasprostranjenost autohtonih i stranih rakušaca (Crustacea: Amphipoda) duž toka rijeke Une

Records of five native and one alien gammarid species are reported from fifteen sites along the entire course of the Una River. Samples of gammarids were collected at ten sites in the main course, and at four sites in small left tributaries of the Una River during field studies conducted from 2005 to 2009. Two endemic species formerly known only from the Adriatic Sea drainage area, Echinogammarus acarinatus and Fontogammarus dalmatinus, were collected for the first time in the Black Sea drainage area at the main spring and in the upper course of the Una River. All three Gammarus species that occur in Croatia have been found in the Una River. Only G. balcanicus was recorded at the upper course, while both G. fossarum and G. roeseli were found in the middle and lower river course. With five gammarid species recorded, the Una River has the highest freshwater gammarid species richness among all of the Croatian watercourses. The new record of the invasive Ponto-Caspian gammarid, Dikerogammarus haemobaphes, in the Sava River at the mouth of the Una River is also reported and discussed.Ovim radom utvrđena je rasprostranjenost rakušaca duž toka rijeke Une i u Savi na ušću Une. Zabilježeno je pet autohtonih i jedna strana vrsta rakušaca iz porodica Gammaridae i Pontogammaridae. Prikupljanje uzoraka provedeno je bentos-mrežom na ukupno petnaest postaja, na deset postaja duž glavnog toka rijeke Une i na četiri postaje na manjim lijevim pritocima te u Savi na ušću Une tijekom terenskih istraživanja u razdoblju od 2005. do 2009. godine. Ovim istraživanjima su na području izvorskog i gornjeg dijela toka po prvi put u Uni zabilježene dvije endemske vrste rakušaca, Echinogammarus acarinatus i Fontogammarus dalmatinus, koje su do sada zabilježene samo u rijekama Jadranskog slijeva, te su ovi nalazi ujedno i prvi nalazi ovih vrsta u Crnomorskom slijevu. U rijeci Uni zabilježene su i sve tri vrste roda Gammarus koje su rasprostranjene na području Hrvatske, od kojih vrsta G. balcanicus dolazi u gornjem toku i u pritoku Klokot, dok su vrste G. fossarum i G. roeseli zabilježene zajedno u srednjem i donjem dijelu toka. S ukupno pet zabilježenih autohtonih vrsta rakušaca, rijeka Una je od svih vodotoka u Hrvatskoj rijeka s najvećim brojem vrsta nadzemnih, slatkovodnih rakušaca. Zabilježen je i novi nalaz invazivne ponto-kaspijske vrste Dikerogammarus haemobaphes u Savi na ušću Une

Nalazi invazivnog rakušca Echinogammarus ischnus (Stebbing, 1899) u Hrvatskoj

The Ponto-Caspian alien and invasive amphipod, Echinogammarus ischnus (Stebbing, 1899), was found in Croatia at three sites in the lower course of the Drava River and at three sites in the Danube River (Batina, Borovo and Ilok). The most upstream site in the Drava where the species was found is a locality near Donji Miholjac, approximately 82 km upstream from the confluence with the Danube River. At this site as well as at two downstream sites (Osijek and Belišće) in Drava it was found together with the dominant invasive amphipods Dikerogammarus villosus and Chelicorophium curvispinum, while at the Donji Miholjac site it also co-occurs with two native species, Gammarus fossarum and G. roeseli.Ponto-kaspijski strani i invazivni rakušac Echinogammarus ischnus (Stebbing, 1899), pronađen je u Hrvatskoj u donjem toku rijeke Drave i na tri lokaliteta u Dunavu (Batina, Borovo i Ilok). Najuzvodnija postaja na kojoj je nađen u Dravi, kod mjesta Donji Miholjac, udaljena je otprilike 82 km od ušća u Dunav. Na toj, kao i na dvije nizvodne postaje (Osijek i Belišće) u Dravi, zabilježen je zajedno s druge dvije invazivne vrste rakušaca Dikerogammarus villosus i Chelicorophium curvispinum, dok na postaji kod Donjeg Miholjca uz ove dvije dominantne strane vrste dolazi zajedno s još dvije autohtone vrste Gammarus fossarum i G. roeseli

Finding of the Alpine salamander (Salamandra atra Laurenti, 1768; Salamandridae, Caudata) in the Nature Park Žumberak - Samoborsko gorje (NW Croatia)

Ovim istraživanjem potvrđena je prisutnost crnog daždevnjaka (Salamandra atra) u Parku prirode Žumberak - Samoborsko gorje, gdje je prethodno zabilježena samo jedna jedinka 1989. godine. Prisutnost i rasprostranjenost vrste istraživani su tijekom vegetacijske sezone 2004. godine na deset različitih lokaliteta u sastojinama planinske bukove šume. U srpnju 2004. g. pronađeno je pet jedinki (četiri mužjaka i jedna ženka) crnog daždevnjaka u bukovoj prašumskoj sastojini Kuta (na oko 900 m n. v.), za vrijeme vremenskih prilika praćenih jakom kišom. Ovo je najsjeverniji nalaz vrste u Hrvatskoj, koji ukazuje da Žumberak predstavlja disjunktni dio njezinog areala u Dinaridima. U radu su predložene mjere zaštite vrste, međutim, za donošenje preciznijeg plana zaštite potrebna su dodatna istraživanja rasprostranjenosti i ekologije ove vrste.This study confirms the presence of Alpine salamander (Salamandra atra) in the Nature Park Žumberak - Samoborsko gorje, where previously only one specimen was recorded in 1989. Species presence and distribution were investigated at ten different localities in stands of montane beech forest, during the vegetation season 2004. In July 2004 five individuals (four males and one female) of Alpine salamander were found in the virgin beech forest at site Kuta (about 900 m a.s.l.), during weather conditions characterized by heavy rain. This is the northernmost finding of the species in Croatia, as well as a confirmed disjunctive part of its areal in the Dinarids. Conservation measures for the species are proposed but for more precise conservation plan further research of species distribution and ecology is needed

Finding of the Alpine salamander (Salamandra atra Laurenti, 1768; Salamandridae, Caudata) in the Nature Park Žumberak - Samoborsko gorje (NW Croatia)

Ovim istraživanjem potvrđena je prisutnost crnog daždevnjaka (Salamandra atra) u Parku prirode Žumberak - Samoborsko gorje, gdje je prethodno zabilježena samo jedna jedinka 1989. godine. Prisutnost i rasprostranjenost vrste istraživani su tijekom vegetacijske sezone 2004. godine na deset različitih lokaliteta u sastojinama planinske bukove šume. U srpnju 2004. g. pronađeno je pet jedinki (četiri mužjaka i jedna ženka) crnog daždevnjaka u bukovoj prašumskoj sastojini Kuta (na oko 900 m n. v.), za vrijeme vremenskih prilika praćenih jakom kišom. Ovo je najsjeverniji nalaz vrste u Hrvatskoj, koji ukazuje da Žumberak predstavlja disjunktni dio njezinog areala u Dinaridima. U radu su predložene mjere zaštite vrste, međutim, za donošenje preciznijeg plana zaštite potrebna su dodatna istraživanja rasprostranjenosti i ekologije ove vrste.This study confirms the presence of Alpine salamander (Salamandra atra) in the Nature Park Žumberak - Samoborsko gorje, where previously only one specimen was recorded in 1989. Species presence and distribution were investigated at ten different localities in stands of montane beech forest, during the vegetation season 2004. In July 2004 five individuals (four males and one female) of Alpine salamander were found in the virgin beech forest at site Kuta (about 900 m a.s.l.), during weather conditions characterized by heavy rain. This is the northernmost finding of the species in Croatia, as well as a confirmed disjunctive part of its areal in the Dinarids. Conservation measures for the species are proposed but for more precise conservation plan further research of species distribution and ecology is needed

Biocontamination of benthic macroinvertebrate assemblages in Croatian major rivers and effects on ecological quality assessment

We studied the composition of non-indigenous macroinvertebrate species (NIMS) and biocontamination level in four major large Croatian rivers (the Danube, Sava, Drava and Mura) to establish which environmental parameters are the most important for the composition of NIMS assemblages and to determine how NIMS affect biological metrics regularly used in ecological quality assessment. We sampled benthic macroinvertebrates at 48 sites (44 lotic + 4 lentic), and among 236 taxa, 21 NIMS were identified, of which 9 were widespread and abundant. Only 14.6% of sites exhibited no biocontamination, 18.7% exhibited low or moderate biocontamination and 66.7% exhibited high or severe biocontamination. Higher biocontamination in the Drava may be due to both the proximity to the Danube as the main source of NIMS and the existence of three large reservoirs. We found significantly negative correlation between the number of NIMS and native taxa. The significant correlations between biocontamination indices and tested biological metrics were as follows: negative with %EPT, EPT-S, BMWP and IBE AQEM, while positive with HR-SI. This indicates that at sites where NIMS are abundant and native taxa scarce, standard biological metrics could provide unreliable results and compromise the assessment of ecological status of large rivers

Biocontamination of benthic macroinvertebrate assemblages in Croatian major rivers and effects on ecological quality assessment

We studied the composition of non-indigenous macroinvertebrate species (NIMS) and biocontamination level in four major large Croatian rivers (the Danube, Sava, Drava and Mura) to establish which environmental parameters are the most important for the composition of NIMS assemblages and to determine how NIMS affect biological metrics regularly used in ecological quality assessment. We sampled benthic macroinvertebrates at 48 sites (44 lotic + 4 lentic), and among 236 taxa, 21 NIMS were identified, of which 9 were widespread and abundant. Only 14.6% of sites exhibited no biocontamination, 18.7% exhibited low or moderate biocontamination and 66.7% exhibited high or severe biocontamination. Higher biocontamination in the Drava may be due to both the proximity to the Danube as the main source of NIMS and the existence of three large reservoirs. We found significantly negative correlation between the number of NIMS and native taxa. The significant correlations between biocontamination indices and tested biological metrics were as follows: negative with %EPT, EPT-S, BMWP and IBE AQEM, while positive with HR-SI. This indicates that at sites where NIMS are abundant and native taxa scarce, standard biological metrics could provide unreliable results and compromise the assessment of ecological status of large rivers

Prvi nalaz Drusus bosnicus grupe (Insecta, Trichoptera) u Hrvatskoj s osvrtom na raznolikost, taksonomiju, rasprostranjenost i ekologiju roda Drusus u Hrvatskoj i dinaridskom kršu Balkanskog poluotoka

In the spring area of the Una River the caddisfly Drusus vespertinus Marinković-Gospodnetić, 1976, which belongs to the Drusus bosnicus group, was recorded for the first time in Croatia. This is the first finding of the Drusus bosnicus group species in Croatia. This paper presents the diversity, distribution and ecology of the genus Drusus in Croatia and in the Dinaric karst on the Balkan Peninsula. Additionally, in this paper we describe the female of Drusus vespertinus.Na izvorišnom području rijeke Une zabilježena je u stadiju adulta i ličinke vrsta Drusus vespertinus Marinković-Gospodnetić, 1976, koja pripada Drusus bosnicus grupi. Ovo je prvi nalaz neke od vrsta Drusus bosnicus grupe u Hrvatskoj. U radu se prikazuje raznolikost, rasprostranjenost i ekologija roda Drusus u Hrvatskoj i u dinarskom kršu Balkanskog poluotoka. Također, u radu se daje opis ženke vrste Drusus vespertinus

Changes in population characteristics and structure of the signal crayfish at the edge of its invasive range in a European river

The ability of rapid range expansion is one of the key determinants of invasive species success. In order to investigate potential drivers behind the rapid spread of invasive species, we explored changes in population characteristics and structure along the invasion pathway of a successful invader in European freshwaters, the signal crayfish (Pacifastacus leniusculus). Diverse population parameters such as relative population abundance, size and sex structure, differences in morphometry and frequency of injuries were compared between signal crayfish population samples at three uniformly distributed segments (approximately 40 km apart) in the lower section of the Mura River, which differed in time since invasion. Examined signal crayfish populations exhibited notable differences, with more recently established populations toward invasion front characterized by lower abundance and male-biased sex ratios, which highlighted males as initial dispersers. We also recorded significant increase in the relative claw size, a competitively advantageous and allometric trait for males, in more recently established populations away from source population. The recorded differences in population structure and male morphometry along the invasion pathway could lead to important clues about dynamics of range expansion and population establishment, highlighting the traits that promote dispersal and better response to local conditions in new habitats. Established differences can also provide insights into the development of targeted management responses aimed at invasive species control