^{© PRASENJEET YADAV}

Advaith Jaikumar

This piece is based on the following study:

​​Vasudev, D., Fletcher, R. J., Srinivas, N., Marx, A. J., & Goswami, V. R. (2022, December 27). Mapping the connectivity–conflict interface to inform conservation. Proceedings of the National Academy of Sciences, 120(1). https://doi.org/10.1073/pnas.2211482119

Thumbnail image Credit: Ganesh Raghunathan

Background

India is home to a unique situation where high densities of people share spaces with wildlife, leading to frequent encounters. It is no surprise that we often come across news articles related to these interactions. Animals need to move between habitats to find resources for basic survival needs. This movement also promotes healthier populations by fostering genetic diversity. However, dispersing animals may come into conflict with people, leading to loss of lives and livestock, and agricultural damage. This may also result in retaliatory action, posing a threat to wildlife. Coexistence has become a primary concern and a goal for people working towards conservation as well as human well-being.

In this context, how can wildlife connectivity and human-wildlife conflict be addressed simultaneously? A new paper by Divya Vasudev, Rob J Fletcher, Nishanth Srinivas, Andrew J Marx and Varun R Goswami introduces a framework that provides simultaneous perspectives of both sides of the paradox. The study, published in the Proceedings of the National Academy of Sciences (PNAS), predicts conflict hotspots and identifies location-specific strategies to minimise human-wildlife interactions and boost connectivity. The authors illustrated the framework using the endangered and wide-ranging Asian elephants in the Mysore Elephant Reserve (ER) as an example.

Asian elephants are important species in the lens of connectivity conservation and conflict mitigation. The Mysore ER is a landscape characterised by a mix of protected areas, reserve forests, and agricultural settlements. It hosts the largest population of elephants in India and is a crucial conservation area with a history of negative human-elephant interactions.

Two of the most common strategies used in the Mysore ER to deal with elephants that come into conflict while dispersing have included fencing and the removal of ‘problem’ elephants. However, while fencing may mitigate conflict, it does so at the expense of elephant dispersal through the landscape. Moreover, there have been reports of increased mortality risk of elephants trying to bypass fences. When it comes to the relocation of elephants, no example illustrates its inefficiency better than the Alur-Sakleshpur case. In 2014, the government relocated 22 elephants that were considered an isolated population. However, in less than a year, the area was recolonised by elephants. This indicates that the population was never isolated and further substantiates the need for conservation strategies tailored to the connectivity–conflict interface.

Method

To provide a solution, the authors developed a framework that derives from random-walk theory – a concept that models animal movement step-by-step and predicts the animals’ next step based on their previous location. They extended the random-walk theory using a mathematical framework called Markov chains. The spatial absorbing Markov chain (SAMC) framework accounts for movement behaviour, mortality risk, and potential conflict for animals that migrate through a landscape. To develop their framework, the researchers collected data from three key elephant populations in the Mysore Elephant Reserve, which served as the starting points for dispersal. They also interviewed locals to gather information on elephant activity and conflict. The interview data helped validate the framework and provided insights into how elephants use the landscape and the areas where conflict is most prevalent. Landscape resistance was shown to be determined by land use and human population density, wherein elephants avoided areas with high population density.

Note: What is landscape resistance? Landscape resistance refers to the extent to which a location is difficult or easy for elephants to move through. Higher resistance values indicate that elephants are less likely to move through those areas and vice versa.

Sites with coconut and areca nut plantations had higher conditional conflict than croplands and agroforest plantations, such as coffee, since elephants tended to avoid the latter two. The study also found that the risk of conflict when elephants moved through an area was slightly higher in regions with high densities of humans.

Using this data, the authors created maps of “landscape resistance” (Map 1) that show where elephants are likely to move and “conditional conflict” maps (Map 2) that show where conflict is likely to occur if elephants use a particular location. Landscape resistance and conditional conflict in the Mysore ER was found to be positively correlated, suggesting that elephants avoided moving through areas with an increased risk of conflict.

Application

The framework addresses the paradox of connectivity and conflict mitigation and helps identify areas where strategies for addressing both can work together. It does so by simplifying the identification of relevant conservation actions in areas depending on the risk of conflict between humans and wildlife. Based on their connectivity and conflict levels, the conservation landscapes are categorised into four scenarios:

The locations of least conservation concern are those that play little or no role in connectivity and face minimal conflict. Here, conservation strategies could focus on habitat restoration, increasing woody vegetation and facilitating connectivity to encourage animal movement through these areas. Areas that allow connectivity and face minimal conflict have the highest potential for long-term conservation and human-wildlife coexistence.

The framework also distinguishes between conflict hotspots with high and low visitation rates by wildlife, and different conservation strategies are needed for each. Insurance schemes or barriers restricting animal entry may suffice for hotspots with low visitation rates since conflict here is sporadic. For hotspots with high visitation rates or in the “connectivity-conflict interface”, deeper deliberation is needed to address conflict while allowing animal movement. Redirecting animal movement to alternative corridors may also reduce negative interactions while maintaining connectivity.

Mitigating conflict and promoting connectivity does not end with identifying conservation strategies. If the concerns of the local communities are not addressed, the situation may worsen. Conservationists, governments, and scientists must engage closely with stakeholders and design long-term strategies involving community-based interventions. Context-specific conservation that allows for movement while minimising conflict is the need of the hour.

^{© PRASENJEET YADAV}

Yashi Dwivedi

A country’s social and economic progress is aided by rapidly expanding road networks, but animals often pay a heavy price for such development. Roads passing through natural habitats hinder animal movement and increase the risk of animals being hit by vehicles while trying to cross.

While road accidents involving larger species like the tiger and elephant often get reported, there is little information available on the impact of roads on smaller animals like birds, reptiles, and amphibians that are equally rare, endangered, or threatened. These species are vulnerable to road effects because of their smaller size, relatively slower speed, and limited road avoidance behaviour, as the asphalt provides warmth on cooler evenings. This is of concern as reptiles and amphibians are among the most rapidly declining taxa globally.

Given their vulnerability, ensuring presence of proper mitigation measures is critical. Mitigation measures are often a combination of barriers (such as fences) that prevent species from crossing roads and lower the risk of mortality, and crossing structures (such as tunnels and underpasses) that provide safe passage for smaller wildlife; facilitating movement and improving wildlife connectivity. However, just incorporating such mitigation methods does not always ensure alleviation of the negative impacts of roads. In order to ensure and improve the success of mitigation measures, examining their use and effectiveness by the target species is vital.

In a recent study, scientists from Laurentian University in Ontario, Canada, investigated the impact of mitigation measures on amphibian and reptile populations in Presqu’ile Provincial Park (PPP), Ontario, Canada. PPP is home to five species of turtles and snakes, three species of salamanders, and nine species of frogs. A road runs right through this park. Although the park did not have any mitigation measures in place when established, a combination of fencing (to prevent crossings), and a couple of tunnels to facilitate crossing were put in place a few years ago. The authors wanted to understand whether mitigation promotes connectivity while lowering mortality. For that, they gathered data on roadkill and successful road crossings before, during, and after the mitigation structures were built. Data was collected using camera-traps placed on either side of the tunnels to capture the species using them. Along with cameras, the authors also tagged a subset of the species using PIT tags and installed scanners to detect the tags at one end of the tunnels.  Additionally, surveys were done three times a day on bicycles to detect road kills and crossings along the road between  2013 and 2018. Surveyors walked the road after conducting bicycle surveys so as to maximise detections.

The authors found that mitigation measures significantly reduced the number of turtles and amphibians on the road. However, they did not have an impact on the number of snakes found on the roads, likely because the snakes were thin enough to  traverse through the fence. Tunnel usage by all studied species was high. Cameras recorded 72 snakes, 615 frogs, 217 salamanders, and 54 turtles using tunnels. In order to understand if the number of crossings observed was enough to maintain connectivity and prevent negative impact of the road on species populations, the authors estimated the population size of a couple of study species—the painted and snapping turtles—in the study area. They found that 5% of painted turtles and 12% of snapping turtles used the tunnels for crossing the road during the study period. Based on other studies, authors suggest this is likely to be enough to prevent road impacts. However, they acknowledge that further investigation is needed.

Mitigation measures that ensure roads do not fragment wildlife habitats are gaining global popularity and are increasingly being incorporated into infrastructure projects within India. However, most of the current mitigation measures are focused on large mammals. Structures like box and pipe culverts, routinely built for passage of water and small streams under roads or railways are often used by amphibians and reptiles. Incorporating considerations around ecology and biology of smaller species while planning placement and design of these culverts, could be a first step towards conservation of often-ignored species. Amphibians and reptiles are essential to the health of the environment and are valuable for natural biological pest control since they are significant predators of numerous insects and agricultural pests. It is important we don’t ignore the little stuff when it comes to linear infrastructure and road-impact mitigation.

Thumbnail Image Credit: A Snapping Turtle in Ontario, Toronto Star