2022 Q2- Primate Welfare Hot Topics

Title: Impact of electrical infrastructure on four populations of primate species in Diani, Kenya

For our spring 2022 feature, we highlight the work of Pamela Cunneyworth, the director at Colobus Conservation in Kenya. Dr. Cunneyworth works to understand and reduce human-primate conflict in the coastal town of Diani, Kenya. We interviewed her about a study recently published in the International Journal of Primatology: Impact of Electric Shock and Electrocution on Populations of Four Monkey Species in the Suburban Town of Diani, Kenya. Since primates may use electrical infrastructure as aerial pathways in areas with limited tree coverage, the potential of electric shock and electrocution is a prominent welfare issue in Diani where urbanization is occurring rapidly. The study included data on four sympatric species found in Diani, Peters’s Angola colobus (Colobus angolensis palliatus), Zanzibar Sykes’s monkey (Cercopithecus mitis albogularis), Hilgert’s vervet (Chlorocebus pygerythrus hilgerti), and the Southern yellow baboon (Papio cynocephalus cynocephalus). Cunneyworth analyzed records of electric shock and electrocution from 1998-2019 and assessed the impact on the populations using annual population census data. The study found that colobus accounted for 80% of cases (4.6% of the population annually), while cases were low for Sykes’s monkeys, vervets, and baboons. Additionally, colobus with a body mass ≥8 kg were more likely to suffer injury and death, therefore adult males were affected more than expected. This finding demonstrates that body mass is an important factor in determining electrical infrastructure risk for arboreal species.

An Interview with dr. Pamela Cunneyworth, Director at Colobus Conservation in Kenya

Title: Impact of electrical infrastructure on four populations of primate species in Diani, Kenya

What are some of the goals of Colobus Conservation and how has the organization helped conservation efforts since being established in 1997?

One of Colobus Conservation’s goals is to minimize human-primate conflict in Diani, a suburban town in southeastern Kenya. Our work ensures the preservation of a valuable conservation population of six primate species (four monkeys and two prosimians), especially the Angolan colobus, listed on the IUCN Red List as Vulnerable to extinction. Human-modified areas are rapidly expanding globally, and these areas typically exclude large and medium-sized animals and often even small animals. The results of our conservation activities counter this global trend, documenting stable primate populations within the town over the past 20 years. 1500 monkeys live in the 7 km2 town; there is, quite literally, a monkey on every corner.

Describe some of the welfare issues wild primates face in Diani. Why did you choose to focus on electric shock/electrocution for this study?

Colobus Conservation’s long-term data show that electric shock and electrocution incidents are the second most commonly reported primate welfare issue in Diani, case numbers only exceeded by primate-vehicle collisions. Power lines and transformers affect colobus monkeys more than any other primate species in the town. Of the colobus, adult males are much more likely to be involved. This has far-reaching implications because the colobus is an infanticidal species; when a new adult male takes over a group after the injury or death of a resident adult male, he kills the infants and sometimes the juveniles of his predecessor, bringing adult females into season soon after the event, ensuring the propagation of the new male’s genes. We have prioritized conservation mitigations to reduce the electric shock and electrocution risk to colobus adult males, thereby shielding cohorts of colobus infants and juveniles.

Your study found that the four different primate species present in Diani [Peters’s Angola colobus (Colobus angolensis palliatus), Zanzibar Sykes’s monkey (Cercopithecus mitis albogularis), Hilgert’s vervet (Chlorocebus pygerythrus hilgerti), and the Southern yellow baboon (Papio cynocephalus cynocephalus)] were affected differently by electrocution and electric shock, with colobus being affected the most. What do you think accounted for the differences?

Interestingly, Sykes’ monkeys follow the same trend as colobus, with adult males more likely to be injured or killed by the power infrastructure than the other age-sex categories but just with fewer cases. This result implicates body size is a significant risk indicator and is likely because, like most primate species, they are sexually dimorphic, meaning that the males are larger than the females. Our study found that individuals >8 kg are at higher risk. We do not know yet why larger individuals are at higher risk, but we suspect that there are differences in how they move in and around the power infrastructure, perhaps because they are less agile and have a higher center of gravity than those that are smaller.

You indicated that electric shock and electrocution cases were higher in months with lower rainfall than months than higher rainfall, why do you think that is?

The reason for the correlation between rainfall and injuries and deaths from the power infrastructure is unknown. However, given the limited food resources during the dry season, colobus may need to travel longer distances to meet their daily nutritional needs than during the rainy season, when food is more plentiful. We expect these longer travel distances during dry season foraging to incorporate more power cable use, putting them at higher risk of electrocution than during the rainy season.

How many cases reported to Colobus Conservation resulted in death? 

Of the 321 power infrastructure-related cases reported in our study, 233 died, which is a whopping 73% of the individuals! This high percentage is because community members typically report these cases when the injury is apparent and therefore very advanced, and treatment is unlikely to succeed.

The article states that you suspect that cases are underrepresented in the dataset. Why do you think this is?

Our team has observed many cases of electric shock during their fieldwork. These cases typically go unreported to Colobus Conservation at the time of the incident because no apparent injury is visible to the observer. We suspect that electric shocks frequently occur, making power infrastructure in wildlife areas an animal welfare issue, even when the impact on the population is not a conservation challenge.

Why do you think the number of incidents reported by the community varied by species?

The number of power infrastructure cases varied depending on the species. These differences are likely an accurate representation of the relative risk across species as our data set does not show trends that suggest otherwise.

Electrical infrastructure has expanded over the years with the growth of Diani, but the number of annual electric shock and electrocution cases has not increased. Describe how Colobus Conservation has partnered with the local electric company to mitigate the risk of primate electrocutions.

Colobus Conservation partners with Kenya Power to reduce the impact of the power infrastructure on Diani’s primates. While this is a goal of Colobus Conservation, Kenya Power is also committed to contributing to biodiversity protection in their areas of operation, a goal formalized in their code of conduct and ethics. Together, we have trimmed trees around power cables and transformers for 20 years, reducing the ability of primates to jump from the vegetation onto the power infrastructure. However, this is a short-term mitigation because of the vegetation regrowth every rainy season. In 2016, Colobus Conservation and Kenya Power began a long-term mitigation of insulating power cables in the areas with the most electric shock and electrocutions cases and moving transformers to safer locations. Excitingly, we document that the number of injuries and deaths due to power infrastructure is not increasing with increasing development in the town.

Does Colobus Conservation intervene when a wild primate is found with injuries from being shocked?

Colobus Conservation operates a 24/7 emergency response service for all primate welfare cases- illness, injuries, and deaths. We receive approximately 250 calls annually. Our vehicle is kept prepared with the equipment necessary to respond in the field because once we receive a call, we give ourselves only 20 minutes to gather the team and leave the premises.

Describe the relationship between humans and wild primates in Diani. What kinds of challenges are faced by humans in the area? Describe how Colobus Conservation engages with the local community to promote conservation and primate welfare.

All Colobus Conservation projects engage the local community. For example, our work with Kenya Power reduces primate welfare cases. It simultaneously reduces power infrastructure damage due to explosions or short circuits caused by the primates jumping on the power cables and transformers. Ultimately, our work reduces people’s risk of injury from damaged power infrastructure and reduces the significant social issues arising from power blackouts, such as children being unable to study without light, food spoilage, or increased risks of abuse in darkened areas. Of course, there would be no damage to the power infrastructure if there were no primates, but Colobus Conservation’s goal is to find innovative ways to promote coexistence between people and wildlife in suburban areas.

What do you see as the most important conservation issue in Diani today?

There are two critical populations for protecting the colobus metapopulation; one is nationally protected, and the other is Diani. Colobus Conservation has worked for 20 years to reduce human-primate conflict in the town, stabilizing Diani’s colobus population at surprisingly high levels compared to the wild. Colobus Conservation is now expanding its area of influence across Kwale County–the only county where Angolan colobus is found in Kenya. We are currently looking for partners to implement a colobus census and forest disturbance survey, important baseline information for strategizing the organization’s next 20-year strategic plan focused on protecting the vulnerable colobus metapopulation and, ultimately, other forest-dependent species.