Naslov
The influence of habitat features on the red listed beetle Graphoderus bilineatus (De Geer, 1774) in floodplain habitats

Autori
Turić, Nataša ; Temunović, Martina ; Szivák, Ildikó ; Herczeg, Róbert ; Merdić, Enrih ; Csabai, Zoltán

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
1 st Central European Symposium for Aquatic Macroinvertebrate Research (CESAMIR) / - , 2014

Skup
1 st Central European Symposium for Aquatic Macroinvertebrate Research and 11 th Hungarian Symposium for Aquatic Macroinvertebrate Research

Mjesto i datum
Szarvas, Mađarska, 10.04.2014. - 13.04.2014

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
water beetles; distribution; association; conservation; floodplains; Croatia

Sažetak
As a typical freshwater species, the dytiscid water beetle Graphoderus bilineatus represents one of few beetles in EU legislation, protected by EU Habitat Directive and Bern Convention. Until the recent past, only two historical records were known in Croatia from 1907 to 1943 and two recent findings from 1990 to 2005. Formerly, Croatia was not included in the range of G. bilineatus. During 2010 we conducted a survey at 30 sampling sites across three largest floodplain complexes in Croatia: Nature Park Kopački rit, Nature Park Lonjsko polje and Spačva basin. We carried out a detailed survey on the influence of habitat features on G. bilineatus occurrence and abundance. We hypothesised that the water beetle assemblages of the three localities are remarkably different and G. bilineatus occurs where the overall water beetle diversity is high. In addition, key environmental factors linked to the variation of water beetle assemblage structure and occurrences of G. bilineatus were identified. Furthermore, we explored which species G. bilineatus is associated with. Sampling was performed by pond-net and baited bottle traps. Eleven environmental variables and plant community types based on Croatian National Habitat Classification were measured and/or estimated for each sampling site. To test our hypothesis, to explore biological patterns and prove our findings multivariate anovas (ADONIS), linear discriminant analysis, partitial cannonical correspondance analysis, linear regression models with Helmert coding and coexistence analysis were used. A total of 4, 339 water beetle specimens belonging to 98 species were recorded. G. bilineatus was recorded at 14 of 30 sampling sites and at 2 of 3 floodplains (Kopački rit- Danube and Lonjsko polje-Sava). Majority of specimens occurred in flooded meadows and in canals or oxbows with riparian and aquatic vegetation of medium density. By analysing the total species dataset of three localities significant differences in water beetle assemblages were found, accompanied by different environmental background and vegetation composition, confirming that localities also differ in their habitat features. A set of environmental variables (density of riparian vegetation, permanent water durability, shading, type of bank) and plant communities (Carex versicaria, Spirodela polyrrhizae, Salvinia natans) best explain the distribution of the water beetle species. Based on the regression model, human impact and shading have significant effects on the abundance of G. bilineatus which indicates the negative effects of the anthropogenic disturbance. Sites with G. bilineatus have significantly higher species richness compared to the sites without. Co-existence analysis indicates positive, negative and neutral associations between G. bilineatus and other water beetle occurrences.

Izvorni jezik
Engleski

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