Human-wildlife interaction is predicted to rise on approximately 57% of the Earth’s land by 2070, which could escalate conflicts between humans and wildlife. Identifying where these interactions are likely to happen, and which animals might engage with humans in specific regions, is vital for urban planners, conservationists, and nations committed to global conservation efforts.
A study from the University of Michigan indicates that by 2070, over half of the planet’s land could see increased interactions between humans and wildlife as the population continues to grow.
According to the researchers at U-M, the rising human-wildlife encounters could result in more disputes between people and animals. It is essential to pinpoint where these overlaps will happen and which species are likely to engage with humans, providing crucial insights for urban development and conservation strategies, especially for countries dedicated to international conservation goals. Their results are detailed in the journal Science Advances.
“Our research indicates that around 57% of global lands will experience increasing human-wildlife interaction, while only about 12% will see a decline in these overlaps. Significant increases are also expected in agricultural and forest areas,” explained Deqiang Ma, the study’s primary author and a postdoctoral research fellow at the U-M Institute for Global Change Biology.
The study concluded that the growing human-wildlife overlap is primarily driven by an increase in human populations rather than climate change. This means that as people settle in previously untouched regions, more overlaps with wildlife will occur, rather than animals changing their habitats due to climate factors.
“In numerous regions globally, more people will interact with wildlife in the upcoming decades, and the wildlife present will often be different from what currently exists,” said Neil Carter, the study’s lead investigator and an associate professor of environment and sustainability. “This will lead to various new interactions between people and wildlife, both positive and negative.”
A human-driven issue
The researchers designed an index that evaluated projected human population growth and the spatial distribution of 22,374 species of terrestrial amphibians, birds, mammals, and reptiles to assess the future human-wildlife overlap.
They utilized existing data that predicts the locations of various vertebrates based on their climatic habits and coupled this with predictions related to human settlement growth influenced by economic development and demographic trends.
“The index we developed showed that most global lands will likely see increased human-wildlife overlap, primarily driven by the expansion of human populations, rather than shifts in species locations due to climate change,” Ma stated.
The findings indicated that areas with high human-wildlife overlap, expected to persist from 2015 to 2070, are mainly located in regions that already have high human population densities, including nations like China and India.
Additionally, “another area of significant concern is the forests of Africa and South America, where we anticipate a notable rise in overlaps in the future,” highlighted Carter. “This is alarming because those regions are rich in biodiversity and will face additional pressures moving forward.”
The study also revealed that species diversity in forests across Africa and South America is expected to decrease. Specifically, mammal diversity may decline by 33% in South America, with amphibians decreasing by 45%, reptiles by 40%, and birds by 37%. In Africa, mammal diversity could drop by 21%, while bird diversity may reduce by 26%.
The need for biodiversity
Maintaining biodiversity in these overlapping regions has substantial advantages, according to Carter.
“There are both beneficial and harmful results from human-wildlife interactions, and we expect these will become more obvious. For example, COVID-19 arose from human interactions with wild animals, raising the concern that new diseases could emerge from increased encounters with particular wildlife species,” he mentioned. “However, some species contribute essential benefits by controlling pest populations.”
For instance, Ma’s analysis considered birds that feed on insects in agricultural fields, investigating how they might adapt under climate change. He discovered that over two-thirds of the cropland likely to experience heightened human-wildlife overlap by 2070 would also see a reduction in bird populations that help manage crop pests.
“We’re identifying those areas and evaluating whether new cropland or pastures will attract species or drive them away,” Carter noted. “It’s crucial to discern if these agricultural zones will pose further threats to species or if we can utilize ecosystem services at no cost.”
Scavenging animals such as vultures and hyenas also play significant roles by cleaning waste in urban and other environments, thus minimizing specific human diseases like rabies, anthrax, and bovine tuberculosis.
“Hyenas, often maligned for being scavengers, provide valuable health benefits,” Carter stated. “They are seen as threats, yet they offer crucial disease management services.”
Equitable conservation
Future conservation efforts must adapt, especially in areas that have previously seen little human presence, the researchers argue. Historically, a primary conservation method has been to create protected areas that limit human access. However, this approach is becoming increasingly difficult due to a shrinking number of untouched landscapes.
“There’s also a significant argument for environmental equity regarding the feasibility of relocating communities that have inhabited certain regions for generations,” Carter added. “Our study indicates that as more areas are expected to be occupied by both people and wildlife, conservation strategies will need to be more innovative and inclusive.”
Conservationists must involve local populations to foster interest in enhancing conservation initiatives. This could include establishing habitat corridors to link existing protected regions and possibly creating temporary protected zones during critical wildlife events, such as breeding seasons, while exploring other conservation strategies.
“We are deeply invested in understanding which areas can sustain endangered species like tigers and how human communities interact with these species,” Carter said. “In some regions, it will be a challenge to balance agricultural growth, urban development, and the protection of these species and their habitats. However, planning proactively can provide many resources to promote sustainable coexistence.”
The study’s co-authors include Briana Abrahms from the University of Washington, U-M ecologist Jacob Allgeier, Tim Newbold from University College London, and U-M evolutionary ecologist Brian Weeks.
