Istraživanje rasprostranjenosti potočnog raka Astacus astacus u slijevu izvorišnog dijela Česme i Ilove u području gornjeg Poilovlja provedeno je od lipnj a do rujna godine 1990. Prisutnost ove vrste utvrđena je u Ilovi (do utoka Šavarnice) , u Peratovici, Rastovcu, Rajčevici, Česmi, Grđevici, Barni i u Grbavcu. Prisutnost nije utvrđena u Ilovi nizvodno od utoka Šavarnice, kao ni u samoj Šavarnici (sl.1 i tabl.1).Investigations of the distribution of the cray.fish Astacus astacus in the catchment of the source part of the Česma and Ilova rivers in the region of Upper Poilovlje were carried out from June to September, 1990. The presence of these species was determined in Ilova (to the mouth of the Šavarnice), Peratovica, Rastovca, Rajčevac, Česma, Grđevica, Barna and Grbavac. Its presnece was not established in Ilova downstream from the mouth of Šavarnica, nor in the river Šavarnica (Figure 1 and Table 1)
