Patterns and Composition of Road-Killed Wildlife in Northwest Argentina

Abstract

Roads have important effects on wildlife, such as natural habitat fragmentation and degradation and direct killing of fauna, which leads to reductions in wildlife population size. We focused on a principal road in Northwest Argentina to test for the effect of seasonality and landscape features on the composition of road-killed wildlife. We conducted regularly scheduled road trips during the dry and wet seasons. We recorded the presence or absence of a vegetation curtain or hedge along the road. We measured land use by remote sensing in a 500 m buffer along the road. We compared the abundance of animals killed between seasons (dry and wet) for different taxonomic groups (mammals, birds and reptiles) and for different origins (domestic and native). We built linear mixed models to test the effect of landscape features on the abundance of killed animals. Two hundred and ninety-three individuals were killed, belonging to 35 species; 75.8 % were native and 24.2 % domestic species. The majority of animals killed were mid-sized mammals. More animals were killed during the dry season. The most important factors to explain the wildlife road-killing were the season and the proportion of agricultural landscape. The composition of the killed animals changed with the season. The proportion of agricultural landscape incremented the number of killed birds and mammals during both seasons, without affecting reptiles. The ratio of wild to domestic animals killed was dependent on the season. This study sets a precedent as the first in road ecology in Northwest Argentina and should be taken into account for road planning and regulation.

Factors influencing the spatial patterns of vertebrate roadkill in South Africa: The Greater Mapungubwe Transfrontier Conservation Area as a case study

“…Ecological or environmental factors are any abiotic or biotic factors that influence living organisms, which may include ambient temperature and amount of sunlight, whilst physical factors are nonliving factors that affect organisms and their survival (Allaby, ). Many studies around the world have investigated the possible ecological and physical factors influencing roadkill occurrence such as season (Garriga, Franch, Santos, Montori, & Llorente, ; Snow, Andelt, & Gould, ), landscape (Cuyckens, MochI, Vallejos, Perovic, & Biganzoli, ; Husby, ; Snow et al, ; Son et al, ), roadside fencing (Braz & França, ; Son et al, ), traffic volumes and vehicle speed (Husby, ; Snow et al, ) and road surface (Braz & França, ). Only a few of these studies have been conducted in Africa (Bullock, Malan, & Pretorius, ; Dean & Milton, ; Drews, ; Haverschmidt, ; Van der Hoeven, Boer, & Prins, ; Kioko, Kiffner, Jenkins, & Collinson, ; Mkanda & Chansa, ; Siegfried, ), and few roadkill studies have assessed ecological and physical factors simultaneously (Burgin & Brainwood, ; Ha & Shilling, ).…”

A Review of the Impacts of Roads on Wildlife in Semi-Arid Regions

“…The numbers and species of reptiles found as roadkill likely underestimates the actual numbers killed, because their relatively small size means they are more likely to be removed by scavengers or flattened beyond recognition, leaving no evidence of collisions. In mesic northern Argentina, Cuyckens et al [32] recorded snakes as roadkill, including a boa and a rattlesnake, but were also unable to identify 13 species of reptile that they found dead on the road. Snakes are predisposed to becoming roadkill owing to their tendency to use road surfaces for thermoregulation [33], their slow movement and need to migrate between habitat patches; other life history traits make their populations particularly vulnerable, including their long lifespans and low reproductive rates, as reviewed by Jochimsen et al [34].…”

“…Many bird species are killed on the roads [32,[40][41][42][43][44][45] and, again, mortality may be underestimated because many are small in size. Unlike snakes in Australia [36], it seems that nocturnal birds are more at risk [46], possibly because birds forage from the roads, which allow clear views of invertebrates in the dusk sky above (e.g.…”

“…The concentration of corn crickets and brown locusts (Locustana pardalina) on roads also attracts other taxa, like raptors, in turn leading to increased collision rates of raptors with vehicles [54]. In Argentina, avian scavengers, including cathartid vultures, Crested Caracara (Polyborus plancus) and unidentified raptors were among the roadkill recorded by Cuyckens et al [32]; similarly, three species of raptor and three species of crow were among the road-killed animals listed for the Karoo [42]; however, many avian scavengers learn to be aware of traffic and fly off on vehicle approach, thereby escaping collision.…”

“…In semi-arid southern Africa, mesomammal scavengers and a diversity of small scavengers are killed whilst foraging on the road [42], which may be a general pattern for small and mesomammal scavenger species being killed on roads in semi-arid regions throughout the world. Opossums (Didelphis marsupialis) were the most frequent roadkill in Venezuela [43], and Pampas (Grey) Fox Lycalopex gymnocercus was the most frequent roadkill in Argentina, followed by Geoffroy's Cat Leopardus geoffroyi and another opossum (Didelphis albiventris) [32], suggesting that they were scavenging roadkill. All these species are about 5 kg in mass; the opossums are perhaps smaller, but all are similar in size to several species of scavenging mongooses in the semi-arid southern African Karoo.…”