Long Term Monitoring of Roadkill Counts: 652 highway

Amir Arnon & Liat Hadar

Road collisions involving animals and vehicles (wildlife-vehicle-collisions; WVC) affect wildlife individuals, populations, and ecosystems. At the same time, they cause economic damage and sometimes even human fatalities.

With the rapid urbanization and expansion of road infrastructure, structured and continuous monitoring of wildlife roadkill, including the species, location, and date, serves as an important source of information regarding trends in animal populations, their spatial and temporal movement patterns, and areas of high-risk for accident (“hot spots”).

In addition to the zoological knowledge to support land management, such information may help to mitigate the problem by various means that affect both the animals and the drivers/the road.

However, most of the data on WVC’s collected by different organizations include only “presence” observations of visible roadkill events, without documenting “absence” data (information on dates at which no accident occurred, and on the sampling effort), which makes it more difficult to analyze the data and draw sound conclusions.

In this report, we summarize a survey conducted along part of Road 652, east of Ramat Hanadiv. The data, collected between 2013-2020, are part of a daily survey (part of Ramat Hanadiv’s long-term monitoring program) that also includes absence data.

The data show that the majority of roadkills in this road segment were jackals (101 individuals throughout the period) and indicate a decrease and a low density of the jackal population in 2013-2017, followed by an increase from 2017 to a significantly higher density by the end of the period. Mongooses and house cats (mostly feral) showed declining trends in parallel with the increase in jackal roadkills, while foxes demonstrated a gradual decline throughout the whole period. In badgers, a small number of roadkills were documented (7 throughout the period), probably due to the low population density and the use of road underpasses. Wild boars and porcupines showed mixed and inconsistent trends. For the gazelle population, roadkill is not a significant cause of death, possibly due to the avoidance of crossing the road with the increase in traffic volume.

In addition, the various species show different patterns throughout the year, depending on the seasonality of foraging, dispersal, and reproduction. Thus, most jackal roadkills occur in the fall, a season in which the young born in the spring disperse.

The spatial pattern of the roadkills also provided interesting information, when differences between species were also observed with respect to roadkill hot spots along different road segments.

Jackals and cats, for example, showed more scattered hot spots, mostly close to areas with increased human impact (supermarket & restaurants in the southern road section; trash cans and cat feeding points further north), while most wild boar and porcupine roadkills occurred along one road segment in the south, which face natural areas and agricultural land.

Along with their scientific and applied contribution, roadkill data are also a way of raising the awareness of decision-makers and the public to the subject, to promote actions by the authorities to reduce the scope of the problem.