Transport-related impacts on wildlife
Animals and people are in danger of being hit by vehicles on roads and railway tracks daily. Almost all drivers have accidentally collided with an animal, be it a small butterfly, a bird, or something larger like a kudu. Wildlife-vehicle collisions seriously impact wildlife populations and are dangerous to vehicle occupants. Habitats and communities are also divided by transport networks such as roads and railway lines. However, these networks are essential for our economies, travel and tourism, and transporting food and goods. We must, therefore, find solutions to reduce the impacts of transport infrastructure on people and wildlife without hindering our transport sector.
What is transport infrastructure?
Transport infrastructure refers to built structures, such as roads and railways, that enable us to transport people and goods. Our roads, railways, pipelines, canals, and power lines, broadly referred to as linear infrastructure, connect our cities and ports, and enable the supply of electricity and water resources.
Transport infrastructure’s impact on wildlife and vice versa
Transport networks are critical to economic development and society, and network construction will likely keep increasing for the foreseeable future, particularly in Africa, which is comparatively underdeveloped. Transport infrastructure has numerous, diverse – and mostly negative – consequences for biodiversity and ecosystem functioning. These impacts include habitat destruction and degradation, fragmentation and disruption of wildlife populations, direct impacts from vehicles colliding with wildlife, and secondary impacts such as the spread of alien plant species or increased human access to previously remote natural resources.
The Endangered Wildlife Trust’s National Roadkill Database for South Africa shows that mammals are the most commonly reported roadkill (50%), followed by birds (18%), reptiles (6%), and amphibians (1%), with 24% of species being unidentifiable. Large mammals, such as carnivores and antelope, are likely to cause damage or delays to trains and vehicles. Collisions with these animals can be expensive, with insurance claims suggesting that approximately R82.5 million is paid yearly against vehicle collisions with wild animals.
wildlife interactions with transport infrastructure
How we reduce these impacts on wildlife
The science of road and rail ecology is relatively well established in North America, Europe, and Australia but is fairly new in Africa. Road and rail ecologists aim to understand the threats to wildlife from transport activities and infrastructure and develop solutions to reduce these threats. The Endangered Wildlife Trust is the only African organisation with a dedicated programme focused on transport and wildlife interactions. The programme works across South Africa and collaborates on projects with colleagues worldwide.
Our goal is to reduce the impacts of transport infrastructure on wildlife and vice versa. We work with the transport sector, universities, and other NGOs to increase our knowledge and capacity to identify threats and recommend targeted evidence-based solutions. Our projects focus on improved understanding and measuring the threats to wildlife from transport activities and infrastructure and identifying solutions suitable to the South African context.
By collecting and analysing wildlife collision data, we look for patterns and trends in roadkill and railkill. We identify areas with high collision rates, times of day or year when specific animals are killed on roads or railways, and what other factors contribute to these incidents. Once we understand where and why collisions are happening, we implement mitigation measures such as installing road signs or temporary fencing. For example, Giant Bullfrogs (Pyxicephalus adspersus) emerge from the ground with the first heavy rains of summer and migrate to nearby breeding grounds in their thousands. Unfortunately, many are killed on roads on their way. Recognising these patterns, timelines, and hotpot areas, we can focus on reducing the roadkill levels within that timeline by erecting temporary structures such as fencing to divert the frogs to cross safely using culverts beneath the road. Another key aspect of our work is raising driver awareness of roadkill hotspots and how to avoid collisions with animals.
Driving global collaboration and research
Much of our work depends on research, and we work with universities to support students studying road and rail ecology. This way, we facilitate knowledge exchange, gather more information, and generate further support. To this end, we have partnered with three of South Africa’s toll concessionaire companies to train their staff to report wildlife incidents and identify species hit by vehicles on their routes. We then analyse these data and recommend measures they can take to reduce wildlife-vehicle collisions in areas with high roadkill rates and address the impact of these collisions on human safety.
Building global connections
The EWT co-hosts the African Conference for Linear Infrastructure and Ecology every three years and the inaugural Global Congress for Linear Infrastructure and Environment was held in September 2021, attended by over 100 delegates from 24 countries.
We participate in several national and international committees:
- The Transportation Research Board (TRB; USA)
- IUCN’s Transport Working Group
- The International Conference for Ecology and Transportation (USA)
- The European-based Infra Eco Network Europe (IENE) and Scientific Expert Committee (Europe)
- Consulting research member of the South African Roads Agency Limited (SANRAL)
Wildlife and Roads
In 2013, the EWT launched several national campaigns to encourage members of the public to submit roadkill sightings. We launched a smartphone application (app) called “RoadWatch”, one of the first roadkill reporting apps in the world. To-date, almost 30,000 data points have been reported via the app. These data records are critical to building our knowledge base and ensuring we receive records from areas we don’t travel to or cannot easily access.
Roads in Parks Project
Following our awareness campaigns, we received feedback from the public about their concern over the rate of roadkill incidents in National Parks, which are predominantly related to speeding and careless driving. South Africa’s protected areas are havens for wildlife, but they are still at risk from road users. We are working with South African National Parks (SANParks) to reduce roadkill in parks by influencing driver behaviour.
Using a field trial, we looked at factors contributing to roadkill in National Parks and how driver behaviour can be altered to reduce it. A common measure to reduce roadkill is using wildlife-warning signs, such as a red triangle with an image of a kudu. However, as drivers become used to the same signs over time, they become less effective. Therefore, we are testing different signs in National Parks to determine which, if any, are most effective in altering driver behaviour. We continue to collect data on roadkill in and around National Parks to monitor the results of methods used to reduce collisions.
A student working with the EWT completed a PhD in 2021. The study tested methods of reducing road-related deaths for Near Threatened Samango Monkeys (Cercopithecus albogularis) in the Soutpansberg. When roads are built in areas with lots of trees, the natural canopy is broken for driver safety and visibility. This forces tree-dwelling species such as monkeys to come down from the tree canopy to cross roads, thereby increasing their risk of being struck by vehicles. The student trialled different bridge designs to identify which one the monkeys were more likely to use if installed. The study revealed that Samango Monkeys and other species such as bushbabies and lizards opted to safely use bamboo poles as alternatives to crossing roads.
Vervet Monkeys (Chlorocebus pygerythrus) are another primate species commonly killed on roads. A student is currently trialling options for alternative crossing structures for Vervet Monkeys in Durban, KwaZulu-Natal. The project aims to identify effective wildlife-friendly bridges that can be installed in roadkill hotspots across the country. Currently, she is experimenting with using rope bridges to connect canopies.
By trialling different designs and methodologies, we identify alternative structures that monkeys and other wildlife are likely to use instead of crossing roads. This will contribute to effective roadkill reduction processes and species management plans, reducing wildlife-vehicle collisions and improving habitat connectivity for wildlife populations.
Wildlife and Rail
The EWT is working to reduce the negative impacts on wildlife of a railway line running through Balule Nature Reserve in the Greater Kruger National Park (GKNP). This railway line extends over 45 km from Hoedspruit to Phalaborwa, and poses a significant threat to local wildlife populations. Since 2011, over 500 fatal wildlife-train collisions have occurred on the railway line, involving Black Rhinoceros (Diceros bicornis), White-backed Vulture (Gyps africanus), African Wild Dog (Lycaon pictus), Hippopotamus (Hippopotamus amphibious), Cheetah (Acinonyx jubatus), Lions (Panthera leo), giraffes (Giraffa camelopardalis), and African Elephants (Loxodonta africana).
We identify hotspot areas and other factors contributing to high rail-kill rates by gathering baseline rail-kill data. We can then recommend appropriate actions the rail operator, Transnet, can take to reduce these incidents and the costs of collisions. Furthermore, we monitor underpasses beneath the railway line using camera traps to determine whether animals use these underpasses and under what conditions they do so. This research will indicate whether constructing additional underpasses and fencing to divert animals through the underpasses would effectively reduce rail-kill.
Stories of success for the wildllife and transport programme
South African students on track
In Balule Nature Reserve, research has provided a baseline indicating there could be over 1,000 vertebrates killed annually on this one railway line. Cameras recording wildlife movement in underpasses capture an average of 80,000 images a month, recording Leopards, lions, Spotted Hyaenas, Cape Porcupines, Common Duikers, and Honey Badgers using the underpasses. These valuable data demonstrate which animals use the underpasses frequently, when they do so, and under what conditions. This is an important step towards being able to recommend tested and targeted rail-kill reduction options to rail operators.
Reducing the toll of roads on wildlife
The EWT and the N3 Toll Concessionaire (N3TC) trialled two roadkill-reduction methods on the N3. The first was temporary roadside fencing directing wildlife to cross safely through underpasses beneath the road. We installed cameras in two underpasses to monitor whether wildlife used the underpasses and were excited to see that several mammals use the underpasses, including Serval (Leptailurus serval), the most common animal killed on the N3. These results indicate that underpasses are a promising alternative for wildlife crossing these roads and others across the country.
Owls and other birds of prey use road structures such as signboards and safety barriers to perch on while hunting prey such as rodents and squirrels. Unfortunately, doing so places the birds at risk of vehicle collisions when they land on the road to feed. The second roadkill-reduction method we tested was placing owl perches 50 m from the road to encourage owls to use these as safer alternatives and not hunt on the roads. Cameras on the owl perches have recorded several birds of prey species using the installed perches for feeding or perching. Our findings suggest that providing alternative structures similar to those on roadsides might reduce the time birds spend on or near roads and their chances of being killed by vehicles. See images captured and read more here.
These trials and monitoring methods, such as camera traps, are invaluable to understanding animals’ interactions with roads. To measure the long-term success of our trials, we will continue to monitor roadkill incidents in the testing areas and compare the roadkill rates to the baseline database we have developed through our partnership with the N3TC.
Did you see the signs?
One of our Roads in Parks students designed a map that helps to predict roadkill hotspots in the park. Based on his findings, we are designing innovative wildlife-warning signs to increase driver awareness in these areas of the park. The other student trialled various sign types, including photographic images and silhouettes of a snake, a Cheetah, and a Greater Kudu, and a speed trap sign. Surprisingly, he found that while drivers said they would respond most positively to the image of a Cheetah and modify their driving behaviour, the snake had the most significant driver response in practice. In the Kruger National Park (KNP), signs displaying photographs of species and the words ‘Roadkill Hotspot’ resulted in a change in driver behaviour and fewer roadkill incidents. These two projects will guide the most appropriate signage placement within the park and suggest that images, specifically photographic ones showing smaller species, are most effective.
How you can help wildlife threatened by transport infrastructure
Submit roadkill reports and photographs to the EWT. Please specify the location of the roadkill (preferably GPS coordinates), the species, and the date you saw it. Email your reports here or download the RoadWatch App from the Google Play Store. These reports help us develop road sensitivity maps that road agencies and environmental planners can use when developing transport corridors. The reports also support us when we motivate for appropriate mitigation measures to be implemented and, ultimately, reduce the impacts of transport on our wildlife.