Human-induced mortality has been identified as a major factor affecting threatened species (López-López et al., Reference López-López, Ferrer, Madero, Casado and McGrady2011; Seshadri & Ganesh, Reference Seshadri and Ganesh2011; Palazón et al., Reference Palazón, Melero, Gómez, De Luzuriaga, Podra and Gosàlbez2012). This includes mortality arising from the development and expansion of power grids (Sundar & Choudhury, Reference Sundar and Choudhury2005; Guil et al., Reference Guil, Fernandez-Olalla, Moreno-Opo, Mosqueda, Gómez and Aranda2011; López-López et al., Reference López-López, Ferrer, Madero, Casado and McGrady2011; Lucas et al., Reference Lucas, Ferrer, Bechard and Muñoz2012). Although overhead electric power lines are known to be one of the factors causing the decline of the Asian elephant Elephas maximus (Gubbi, Reference Gubbi2009), there are few studies in India that address this problem.
The Asian elephant is categorized as Endangered on the IUCN Red List (Choudhury et al., Reference Choudhury, Lahiri Choudhury, Desai, Duckworth, Easa and Johnsingh2008), and listed on Appendix I of CITES (CITES, 2013) and Schedule I of the Indian Wildlife (Protection) Act, 1972. Habitat loss, fragmentation and illegal killing for ivory are believed to be the main causes of the decline of this species (Sukumar, Reference Sukumar2006). The state of Odisha supports the largest population (c. 1,930 elephants) in central India (Elephant census report 2012, unpubl. data). The aim of our study was to examine the degree to which electrocution is a significant cause of elephant mortality in Odisha, which has an area of 155,707 km2 of which forest covers 58,136 km2.
In 2011 the total human population of Odisha was 41,974,358, with a density of 269 km−2, the majority of whom (80%) are rural (Anon., 2011). The principal crop is rice, mainly cultivated in the monsoon (July–October) and harvested from October to December. Most precipitation falls during the monsoon, with a mean annual total rainfall of 1,451 mm; temperatures range from a minimum of 2 °C in winter to a maximum of 45 °C in summer (Anon., 2012). There are two types of power lines in the state. Supply power lines consist of two parallel wires at a height of 5.5 m, carrying 220–440 volts. High-tension power lines consist of three sets of parallel wires, with the lowest set at a height of 6.5 m, carrying 11,000–44,000 volts (Odisha Electricity Regulation Commission, Bhubaneswar, pers. comm.). The network of above-ground power lines has increased in the last 30 years, accompanied by an increase in infrastructure, including roads, canals, railway lines and power generation and distribution facilities (Dash & Sangita, Reference Dash and Sangita2011).
We searched local and English language media sources and reports of government and non-governmental organizations for information on elephant deaths from electrocution during a 12-year period (2001–2012). All data were verified by visits to sites and by conducting informal interviews with government officials, local people and local community leaders.
Mortalities were coded by location (categorized into four broad habitat types: agricultural areas, reserve forests, sanctuaries and near highways), time of death and information on the age and sex of the elephants. Mortalities from power lines were categorized into intentional and unintentional electrocution. Intentional describes an elephant killed by a power line used to protect a crop field, or for poaching. The technique used for such killing consists of a wire, with an insulated rod or dry bamboo cane, attached to a high-tension power line running through a known elephant path. The wires are secured at the approximate chest height of an elephant, and the animal normally dies instantly.
We collated reports of a total of 118 elephants killed in 91 incidences of electrocution during 2001–2012, in 28 of 30 elephant range districts in Odisha. The mean annual mortality was 9.8 ± SD 4.2 elephants, with a maximum of 18 deaths in 2011 (Fig. 1). Of these 91 incidences, 34 (37.4%) were intentional electrocution by poachers. In 48 cases the time of the incidence was available, and 44 incidences (91.7%) occurred during the night. Mortality varied seasonally, with the highest mortality in the monsoon (59.3%), followed by winter (November–February, 26.4%) and summer (March–June, 14.3%). The greatest number of electrocutions (62.6%) were recorded when crops were being harvested (October–December). The majority of mortalities occurred while the elephants were in agricultural areas (75.8%), followed by reserve forests (18.7%), sanctuaries (3.3%) and close to highways (2.2%). Most electrocutions were of lone elephants (75.8%), although groups of two (18.7%) or three (5.49%) elephants were also electrocuted. Of the 118 recorded deaths 68 were males (66 adults, two juveniles) and 50 females (49 adults, one juvenile).
The increase in the number of elephants killed by electrocution (Fig. 1) is probably related to the increase in the human population of Odisha, which rose from 3.67 million in 2001 to 4.19 million in 2011 (Anon., 2011). The growth of the human population has led to encroachment on elephant habitat, forcing elephants to move into agricultural fields to forage (Gubbi, Reference Gubbi2009), particularly during the harvest period, when raiding by elephants is most common (Sar & Lahiri-Choudhury, Reference Sar and Lahiri-Choudhury2006).
When an elephant continuously raids a crop the local community may deliberately kill it using an electric power line, poisoning or a firearm. Gubbi et al. (Reference Gubbi, Swaminath, Poornesha, Bhat and Raghunath2014) also reported electrocution of elephants on farms in the state of Karnataka. In addition, the financial lure has caused some local people to turn to elephant poaching. The current management strategy attempts to address poaching by taking action under the Indian Electricity Act, 2003, and Indian Wildlife (Protection) Act, 1972. The state forest department has taken steps to reduce the electrocution of elephants by collaborating with the state energy department to improve electrical infrastructure in elephant habitats. There are plans to increase the height of high-tension power lines, provide earth-leakage circuit breakers in forested areas and clear vegetation on both sides of power lines.
To prevent electrocution of elephants we recommend several strategies. Joint patrolling in high-risk agricultural and forest areas by forest department staff and participatory programmes involving NGOs and local communities could reduce mortality from electrocution. The relevant authorities could tackle poaching by electrocution through gathering and sharing intelligence between forest departments and law enforcement agencies. Where feasible, the electricity supply could be interrupted during the night in high-risk areas, with the cooperation of local people and the local administration. In remote high-risk areas alternative power sources such as solar panels could be installed. Guard spikes could be added to electric poles at suitable heights, to discourage rubbing by elephants, and there needs to be monitoring of damage to electrical infrastructure. We support the recommendation of Rangarajan et al. (Reference Rangarajan, Desai, Sukumar, Easa, Menon and Vincent2010) for greater use of low-tension electric wires and increasing the height of high-tension power lines through elephant habitats. Local communities could be encouraged to cultivate less palatable species near electric power lines. Securing the goodwill, trust and support of the local communities residing near elephant habitats could be ensured by adoption of simple and rapid compensation schemes, community insurance schemes, awareness programmes and provision of enhanced alternative livelihood options.
We have communicated these recommendations to the forest department. Such measures, either singly or in various combinations, depending on the local situation, would help reduce elephant mortality by electrocution from power lines.
We thank the Principal Chief Conservator of Forests (Wildlife) and Chief Wildlife Warden, Odisha Forest Department, for facilitating this study, Mr K.K. Panigrahi, Assistant Conservator of Forests (Wildlife), for his valuable support, and all Divisional Forest Officers and field staff for their kind co-operation, and we appreciate the valuable input of Niladri B. Kar, Manish Bakshi and two anonymous reviewers.
Nimain Charan Palei is studying human–elephant conflict management and implementation of corridor management for safe passage of elephants between fragmented habitats. For the past 5 years he has been studying elephant migration to Odisha from the neighbouring states of Jharkhand and West Bengal. Himanshu Shekhar Palei has a particular interest in mammalian population dynamics and human–animal conflict. Bhakta Padarbinda Rath is responsible for database management, censusing and website management for improved conservation of elephants in Odisha. Chandra Sekhar Kar was involved for 35 years in wildlife research, monitoring and conservation activities in Odisha. He passed away in April 2014.