Fig 1.
Investigated green bridges and viaducts.
(A) Map of Croatia showing positions of the monitored green bridges and viaducts along the A1 motorway and wolf pack home ranges. Wolf range in Croatia is depicted in yellow. Total number of recorded photographs/movies with wolves on green bridges and viaducts is shown in blue and green, respectively. Map of Croatia representing motorway network was obtained from State Geodetic Administration (Republic of Croatia) and is used with their permission; (B) Night-time wolf pack photograph on the viaduct MP; (C) Daytime wolf photograph on the green bridge IB. Green bridges: IB—Ivačeno brdo, MG—Medina gora, VAR—Varošina, OSM—Osmakovac, RO—Rošca, KON—Konšćica; viaducts: GRABA—Graba, SUV—Suvaja, MP—Mandarića potok, GRABARA—Grabara.
Fig 2.
Abundance trends of wolf packs using monitored green bridges.
Event—a photograph/movie of a wolf/wolves. Maximal number of wolves recorded in a single event for each year, i.e. minimal pack size, is marked above bars.
Fig 3.
Abundance trends of wolf packs using monitored viaducts.
Event—a photograph/movie of a wolf/wolves. Maximal number of wolves recorded in a single event for each year, i.e. minimal pack size, is marked above bars.
Fig 4.
Abundance trends of natural prey (roe deer, red deer and wild boar combined) on the monitored green bridges.
Event—a photograph/movie of natural prey.
Table 1.
Testing the correlation between abundance trends of wolves and (i) their prey and (ii) human-caused wolf mortality in the southern part of wolf range (packs OSM and RO+KON).
Fig 5.
Negative correlation between wolf abundance trends and legal wolf cull in southern Croatia.
Wolf population trend is presented as a total number of events (photographs of wolf/wolves) recorded on Dalmatian green bridges. The data for the legal cull in the corresponding Split-Dalmatia County during the monitoring period was extracted from the literature.
Table 2.
Benefits and limitations of camera traps on crossing structures used as a wildlife monitoring tool.
Table 3.
Cost-efficiency of various camera trapping studies.