The study also underscores the need for evolving conservation strategies. Traditional approaches, such as establishing protected areas with restricted human access, are becoming increasingly difficult to implement as human activity encroaches on these spaces.
A groundbreaking study from the University of Michigan forecasts that by 2070, more than half of the world’s land will experience increased human-wildlife overlap, leading to heightened interactions between people and animals. This research, published in Science Advances on Wednesday, underscores the urgent need for effective strategies to manage these interactions as human populations expand.
Titled “Global Expansion of Human-Wildlife Overlap in the 21st Century,” the study reveals that approximately 57 per cent of the world’s terrestrial areas will see an increase in human-wildlife overlap, while only 12 per cent will experience a decrease. The research highlights that this trend will be primarily driven by human population growth rather than climate change, which will play a less significant role in altering wildlife distributions.
Deqiang Ma, the study’s lead author and a postdoctoral research fellow at the U-M Institute for Global Change Biology, explains, “Our findings indicate that as human populations spread into previously undeveloped areas, the overlap with wildlife will increase significantly. Agricultural and forested regions will see substantial rises in these interactions.”
The study’s findings emphasize the need for urban planners, conservationists, and policymakers to anticipate and manage the complex dynamics of increased human-wildlife encounters. As urban areas and agricultural lands expand, the nature of these interactions will change, potentially leading to new conflicts and opportunities for both people and animals.
Neil Carter, the study’s principal investigator and associate professor of environment and sustainability at the University of Michigan, notes, “In many regions, people will come into contact with different wildlife species than they do today. This will result in novel interactions, both beneficial and detrimental.”
A human-driven issue
To assess future human-wildlife overlap, researchers developed an index that integrated projections of human settlement patterns with spatial distributions of 22,374 species of terrestrial amphibians, birds, mammals, and reptiles. This index combined data on species’ climatic niches with predictions of global population growth, economic development, and demographic trends.
The study highlights regions already experiencing high levels of human-wildlife overlap, such as China and India, which are expected to see continued increases. Additionally, forests in Africa and South America are identified as areas of significant concern due to their high biodiversity and the projected rise in overlap.
In Africa and South America, biodiversity is expected to face considerable pressures. The study forecasts a decline in species richness across most forests in these regions. In South America, mammal richness may drop by 33 per cent, amphibian richness by 45 per cent, reptile richness by 40 per cent, and bird richness by 37 per cent. Africa is expected to see a decline in mammal richness by 21 per cent and bird richness by 26 per cent.
Preserving biodiversity amid increasing human-wildlife interactions is crucial, Carter argues. While some interactions can lead to negative outcomes, such as the emergence of diseases like COVID-19 from wildlife contact, others provide essential benefits. For instance, birds that prey on crop pests can play a vital role in agriculture, and scavengers like vultures and hyenas help manage waste and reduce disease prevalence in urban areas.
Ma’s analysis highlights the potential decline in pest-controlling bird species in agricultural lands due to increased human-wildlife overlap. “We need to consider how changes in species distribution might affect ecosystem services that benefit agriculture,” Ma says. “Understanding these dynamics can help us better manage and protect these services.”
Need for biodiversity
The study also underscores the need for evolving conservation strategies. Traditional approaches, such as establishing protected areas with restricted human access, are becoming increasingly difficult to implement as human activity encroaches on these spaces. Carter emphasizes the importance of engaging local communities in conservation efforts and developing innovative strategies to balance human and wildlife needs.
Future conservation planning may include creating habitat corridors to connect existing protected areas, establishing temporary protected zones during critical wildlife periods, and fostering community involvement in conservation efforts. “As human and wildlife habitats increasingly overlap, we must find creative and inclusive solutions to manage these interactions and promote sustainable coexistence,” Carter says.
The University of Michigan study highlights a critical challenge for the coming decades: managing the expanding overlap between human and wildlife populations. By understanding where these interactions will intensify and developing strategies to address both the risks and benefits, policymakers and conservationists can work towards more sustainable coexistence between humans and the natural world.
