Long-term history of vehicle collisions on the endangered Nēnē (Branta sandvicensis) (original) (raw)
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One of the most obvious impacts of roads on wildlife is vehicle-induced mortality. The aims of this study were to examine the spatial pattern of mammal-vehicle collisions (MVCs), identify and examine factors that contribute to MVCs, and determine whether the factors that increase the odds of MVCs are similar between species. On 103 road surveys that covered 7,094 total km I recorded the location of each MVC along the survey route. I measured landscape and roadway features associated with each MVC and used kernel density and network analysis tools to identify road mortality hotspots and measure spatial clustering of MVCs. I used logistic regression to model the likelihood of MVCs for all mammal data and separately for Porcupine (Erethizon dorsatum), Raccoon (Procyon lotor), Skunk (Mephitis mephitis), Muskrat (Ondatra zibethicus) and Cottontail (Sylvilagus floridanus) data sets. I identified 51 MVC hotspots and found spatial clustering of MVCs for Porcupines, Raccoons and Skunks. Two landscape variables, distance to cover and the presence of an ecotone, as well as one road variable, road width, appeared as broadly important predictors of mammalian road mortality, though there was also speciesspecific variation in factors that increased the risk of MVCs. Field-measured variables were more important than remotely-measured variables in predicting the odds of MVCs. Conservation implications are that mitigation of landscape features associated with higher risk of vehicle-collisions may reduce the number of MVCs in general, but species-specific research is required to more carefully tailor mitigation efforts for particular species.
Estimates of Avian Mortality Attributed to Vehicle Collisions in Canada
Avian Conservation and Ecology, 2013
Although mortality of birds from collisions with vehicles is estimated to be in the millions in the USA, Europe, and the UK, to date, no estimates exist for Canada. To address this, we calculated an estimate of annual avian mortality attributed to vehicular collisions during the breeding and fledging season, in Canadian ecozones, by applying North American literature values for avian mortality to Canadian road networks. Because owls are particularly susceptible to collisions with vehicles, we also estimated the number of roadkilled Barn owls (Tyto alba) in its last remaining range within Canada. (This species is on the IUCN red list and is also listed federally as threatened; Committee on the Status of Endangered Wildlife in Canada 2010, International Union for the Conservation of Nature 2012). Through seven Canadian studies in existence, 80 species and 2,834 specimens have been found dead on roads representing species from 14 orders of birds. On Canadian 1 and 2-lane paved roads outside of major urban centers, the unadjusted number of bird mortalities/yr during an estimated 4-mo (122-d) breeding and fledging season for most birds in Canada was 4,650,137 on roads traversing through deciduous, coniferous, cropland, wetlands and nonagricultural landscapes with less than 10% treed area. On average, this represents 1,167 birds killed/100 km in Canada. Adjusted for scavenging, this estimate was 13,810,906 (3,462 dead birds/100 km). For barn owls, the unadjusted number of birds killed annually on 4-lane roads during the breeding and fledging season, within the species geographic range in southern British Columbia, was estimated as 244 owls and, when adjusted for scavenging and observer bias (3.6 factor), the total was 851 owls. RÉSUMÉ. Bien que l'estimation de la mortalité aviaire attribuable aux collisions automobiles soit de l'ordre des millions aux États-Unis, en Europe et au Royaume-Uni, il n'existe aucune estimation de ce genre au Canada à ce jour. Pour pallier cette lacune, nous avons calculé une estimation de cette mortalité aviaire annuelle durant la saison de nidification et d'envol des jeunes, dans les écozones canadiennes, à partir de données issues de la littérature nord-américaine que nous avons appliquées au réseau de transport canadien. Étant donné que les chouettes et hiboux sont particulièrement susceptibles d'être happés par des véhicules, nous avons aussi estimé le nombre d'Effraies des clochers (Tyto alba) happées dans le peu qu'il reste de son aire de répartition au Canada. (Cette espèce figure sur la liste rouge de l'UICN et est aussi listée comme « menacée » au palier fédéral; Comité sur le statut des espèces en péril au Canada 2010; Union internationale pour la conservation de la nature 2012.) À partir de sept études canadiennes sur le sujet, 80 espèces et 2 834 spécimens ont été trouvés morts sur les routes; ces espèces font partie de 14 ordres d'oiseaux. Sur les routes canadiennes pavées à une ou deux voies et situées à l'extérieur des grands centres urbains, le nombre non ajusté de mortalités aviaires par année, pour les 4 mois (122 jours) que dure la saison de nidification et d'envol des jeunes chez la plupart des oiseaux au Canada, s'élève à 4 650 137 en milieux décidus, conifériens, cultivés, humides ou non agricoles comportant moins de 10 % d'arbres. En moyenne, ce résultat se traduit par 1 167 oiseaux happés/100 km au Canada. En ajustant pour tenir compte de la disparition des carcasses par les charognards, cette estimation s'élève à 13 810 906 (soit 3 462 oiseaux happés/100 km). Pour ce qui est de l'Effraie des clochers dans son aire de répartition du sud de la Colombie-Britannique, le nombre non ajusté d'oiseaux happés annuellement sur les routes à quatre voies durant la saison de nidification et d'envol des jeunes s'élève à 244; ce nombre grimpe à 851 lorsqu'il est ajusté pour prendre en compte les biais associés aux observateurs (facteur de 3,6) et à la disparition des carcasses par les charognards.
Spatial and Seasonal Variation in Wildlife-Vehicle Collisions
To understand seasonal variation in the number of wildlife-vehicle collisions and the influence of land cover type on collision distribution we counted road-kill carcasses for 84 weeks along a 40 km route on two state highways in northeastern Kansas. We noted land cover type adjacent to each road-kill and tested the null hypothesis that road-kills were distributed randomly with respect to land cover type. Wildlife-vehicle collisions were not distributed randomly in relation to land cover availability. Instead, collisions occurred more often then expected adjacent to riparian areas and less often than expected adjacent to agricultural fields. Wildlife-vehicle collisions varied seasonally and occurred most frequently during the fall. Seasonal changes in traffic volume were not related to the number of wildlife-vehicle collisions observed. Knowledge of land cover types in which wildlife-vehicle collisions are more likely to occur might help wildlife managers and state transportation de...
Examining Patterns of Animal–Vehicle Collisions in Alabama, USA
2014
Animal–vehicle collisions (AVCs) cause animal death, human injury, and vehicle damage. Uncovering the general patterns and related ecological processes of AVCs is useful for developing mitigation strategies. We examined some previous patterns about AVCs from records in Alabama during 2001 to 2011. The results confirm that: (1) there was a seasonal pattern, with >50% of AVCs occurring in winter; (2) AVCs occurred most frequently at dawn and dusk in the diurnal pattern; and (3) most AVCs occurred on county highways. However, interstate and federal highways had higher numbers of AVCs per km of road. Counties within metropolitan areas had more AVCs. We analyzed 1,000 AVC cases selected at random from the all reported cases and found that 74% of AVCs had forested landscapes on both sides the road. At the county level, AVCs occurred more frequently in areas with greater human population density and less frequently in areas with few roads. The implications for mitigating human–wildlife ...
Road Ecology Center, 2003
The trends of increasing traffi c volumes and road densities will only magnify the already adverse effects roads have on large mammals and other vertebrates. Development of practical highway mitigation will rely on an understanding of patterns and processes that result from highway accidents, which involve elk Cervus elaphus and other large animals. We specifi cally address three areas relating to the patterns and characteristics of large-animal vehicle collisions on different road-types in the Central Canadian Rocky Mountains. First, we investigate the spatial error associated with reported wildlife-vehicle collisions (WVCs). Second, we look at the demographic and temporal patterns of elk and wildlife-vehicle collisions on different road-types. Finally, we investigate the type of vehicles involved in WVCs and what conditions contribute to injury-related accidents. We found that the average reporting error from park wardens, highway maintenance contractors and from Royal Canadian Mounted Police (RCMP) data ranged from 300m-2000m. The sex ratio of elk-vehicle collisions (EVCs) was signifi cantly different from that found in the population, and highly skewed towards greater male mortality during the 15-year period. The age ratio of EVCs was highly skewed towards greater subadult mortality. We found no difference in marrow fat content between highway and railway killed elk, but both had higher fat content than predator-killed elk. EVCs were signifi cantly higher on the Trans-Canada Highway (TCH) in the province which had the highest traffi c volumes. The TCH in Banff National Park (BNP) had a signifi cantly higher rate of EVCs than the secondary highway (93S) in Kootenay National Park. EVCs declined over time on the unmitigated section of TCH in BNP and on highway 93S, even though traffi c volumes were increasing. We found that local elk abundance was decreasing and was the driving force in EVC rates; however, traffi c volume determined the rate of EVCs on different road types. WVCs occur more often than expected at dusk and night periods and on weekends. Injury-related WVCs are more likely to occur in dry conditions than in slush, snow or icy conditions. Injury-related WVCs are more likely to occur with smaller vehicles than in larger vehicles. Further, larger vehicles were involved in more WVCs than expected on two of our road-types. In conclusion, spatial road-kill data can aid in determining location of mitigation measures, e.g., wildlife signage and crossing structures. Patterns of WVCs can be valuable in devising mitigation based on specifi c hour of day or season when collision frequencies are highest, and what individuals within a population are most susceptible to road-kills. Factors contributing to WVCs, such as traffi c volumes and elk abundance, can help managers predict long-term viability of wildlife populations with incurring road mortality.
An Approach Toward Understanding Wildlife-Vehicle Collisions
Environmental Management, 2008
Among the most conspicuous environmental effects of roads are vehicle-related mortalities of wildlife. Research to understand the factors that contribute to wildlife-vehicle collisions can be partitioned into several major themes, including (i) characteristics associated with roadkill hot spots, (ii) identification of road-density thresholds that limit wildlife populations, and (iii) speciesspecific models of vehicle collision rates that incorporate information on roads (e.g., proximity, width, and traffic volume) and animal movements. We suggest that collision models offer substantial opportunities to understand the effects of roads on a diverse suite of species. We conducted simulations using collision models and information on Blanding's turtles (Emydoidea blandingii), bobcats (Lynx rufus), and moose (Alces alces), species endemic to the northeastern United States that are of particular concern relative to collisions with vehicles. Results revealed important species-specific differences, with traffic volume and rate of movement by candidate species having the greatest influence on collision rates. We recommend that future efforts to reduce wildlife-vehicle collisions be more proactive and suggest the following protocol. For species that pose hazards to drivers (e.g., ungulates), identify collision hot spots and implement suitable mitigation to redirect animal movements (e.g., underpasses, fencing, and habitat modification), reduce populations of problematic game species via hunting, or modify driver behavior (e.g., dynamic signage that warns drivers when animals are near roads). Next, identify those species that are likely to experience additive (as opposed to compensatory) mortality from vehicle collisions and rank them according to vulnerability to extirpation. Then combine information on the distribution of at-risk species with information on existing road networks to identify areas where immediate actions are warranted.
Vehicle Collisions Cause Differential Age and Sex-Specific Mortality in Mule Deer
Advances in Ecology, 2014
As roads continue to be built and expanded, it is important that managers understand the effects that vehicle-related mortality can have on the population dynamics of wildlife. Our objective was to examine the frequency of mule deer (Odocoileus hemionus) vehicle collisions to determine if different demographic groups showed differential susceptibility to mortality when compared with their proportion in the population. We also compared vehicle collision rates of mule deer, elk (Cervus canadensis), and moose (Alces alces) to determine their relative vulnerability to vehicle collisions. We found that 65% of mule deer involved in vehicle collisions were female; of those, 40% were adult does ≥2 yrs. When we compared the proportion of bucks, does, and fawns killed in vehicle collisions to surveys of live deer, we found that bucks were killed at rate of 2.1–3.0 times their proportion in the population. Additionally, when we compared vehicle collision rates for 2010 and 2011, we found that ...