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ŠUMARSKI LIST 3-4/2019 str. 57     <-- 57 -->        PDF

Directive – Cerambyx cerdo Linnaeus, 1758. Twenty-four species have an IUCN Red List status – 15 are Least Concern (LC), while nine are Near Threatened (NT). Of those two categories, ten and seven are saproxylic, respectively, i.e. in some way dependant and/or connected to the decay of wood at least during a part of their life cycle.
With little-to-no data published for other wetlands in Croatia, it is almost impossible to put our results in any meaningful perspective. Tallósi (2008) lists 173 species of Carabidae along the Drava river and in Baranja, including a part of Kopački Rit. Kopački Rit by itself has a total of 275 beetle species, of which 155 are Carabidae (Krčmar, 2014; Kulundžić et al., 2014). Both areas are larger than Turopoljski Lug and contain more habitat types, and were researched more, so their larger number of species is not surprising. Nevertheless, future beetle research in Turopoljski Lug is expected to yield many more additions to the current species list.
Three Natura 2000 species are listed for the site Odransko Polje: Lucanus cervus (Linnaeus, 1758), Graphoderus bilineatus (De Geer, 1774), and C. cerdo, of which we only found the latter. This could be because the forest itself periodically floods, which is not a favourable condition for the larvae of L. cervus. This species probably prefers more elevated and/or drier locations, possibly outside of the Turopoljski Lug forest. Future research should investigate in more detail its occurrence in and around the forest. The second species, G. bilineatus, is an aquatic beetle living in mostly stagnant permanent waters (Cuppen et al., 2006; Temunović and Turić, 2015). It is fairly rare in Croatia, and the best chance of finding it is by placing funnel traps in suitable aquatic habitats (Temunović and Turić, 2015; Volkova et al., 2013). Since we did not employ this methodology, it is not surprising that we did not find this species. A literature record was found for a fourth Natura 2000 species from Turopoljski Lug – Phryganophilus ruficollis (Fabricius, 1798) (Schlosser, 1878). This species has not been listed on the reference list for Croatia due to a complete lack of recent records since no one looked for it since and there is no monitoring protocol. Therefore, it would be recommendable to invest in targeted research actions to ascertain if P. ruficollis is still present in Turopoljski Lug and assess its status if it is.
Although the European Red List of Saproxylic Beetles covers many beetle species at the European level (Nieto and Alexander, 2010), there are still many taxa that are not evaluated at the European level. In Croatia, only the Red List of Carabidae exists, with all other beetle taxa not being evaluated as of yet (Vujčić-Karlo et al., 2007). Due to damaged, sick and rotting trees not being viewed as valuable from the lumber industry’s standpoint, they are often removed from forests. However, those trees are of vital importance from a biodiversity standpoint, because one such tree can serve as a home to whole communities of organisms, including saproxylic beetles, for decades. Their removal has been shown to be the gravest threat to both threatened and non-threatened saproxylic beetles in all of Europe (Nieto and Alexander, 2010). Therefore it is certainly recommended to modify current practices and leave old trees, tree stumps and logs in all parts of the forest, as it is already mandated by the Forestry Act (Anonymous, 2005), so some suitable habitat would still remain to ensure the long-term survival of such species (Tvrtković, 1997b). Additionally, Red Listing of other beetle groups should be carried out at the earliest possible convenience, both at the Croatian and European levels, to facilitate better nature conservation practices.
Three of the recorded species can be characterised as rare in Croatia: Trox perrisii Fairmaire, 1868, Gnorimus variabilis (Linnaeus, 1758), and Elathous impressifrons (Hampe, 1866). The first one has only recently been discovered for Croatia, on Ivanščica Mt. and on the Istria peninsula (Koren, 2015; Ziani et al., 2015). This is the third record for this species in Croatia. G. variabilis is rare in Europe and has a fragmented population throughout its range. Declines are reported from a number of states (Mannerkoski et al., 2010). Even though there are several literature records for Croatia (Koča, 1905; Mikšić, 1965; Müller, 1902; Novak, 1952; Schlosser, 1878), there were no recent records till 2015 (Šag, 2015). We found remains of an adult beetle while examining red rotten oak tree trunk in Turopoljski lug in March 2015.
Elater impressifrons is a poorly known beetle. It was described from the vicinity of Zagreb (Hampe, 1866). Schlosser (1878) mentions that the Croatian entomologist Julija Stiegler collected it in Turopoljski Lug forest in wood mould of oak tree hollows. This is so far the only precise known locality for this species. A female specimen of this species from Croatia, without any other collecting details, is deposited in the Coleoptera collection of the Hungarian Natural History Museum (Tamás Németh, personal communication). The species wasn’t recorded during this research, suggesting more focused surveys are required in the future.
Two of the recorded species are alien – Harmonia axyridis Pallas, 1773 and Diabrotica virgifera LeConte, 1858. The former, an invasive species that is now widespread in Europe, had first been recorded in Croatia in 2008 (Mičetić Stanković et al., 2010). It is known to have a negative influence on the native coccinellid fauna (Roy and Wajnberg, 2008). Since no previous published records exist for Coccinellidae of Turopoljski Lug, it will be impossible to know the changes in the fauna from before the arrival of H. axyridis. The current situation should be investigated in more