Overview
According to a newly published UM study in the journal Science Advances, human-wildlife overlap is projected to increase across more than half of the world’s lands by 2070, mainly due to human population growth, with Africa seeing the largest increase at 70.6%, followed by South America at 66.5%.
Species richness, or the number of species present, will decrease in many areas as animals move to new habitats due to climate change, though in some regions, both human population density and species richness will increase.
Increased overlap between humans and wildlife can lead to negative outcomes, such as conflicts and the spread of diseases, but also provides benefits like pest control from birds and improved mental health from observing wildlife.
- The study underscores the need for local research to understand the specific impacts of increased human-wildlife overlap, including species behavior and the nature of interactions between people and wildlife.
- Conservation strategies should focus on habitat corridors, rewilding areas, and engaging local communities to promote coexistence, in alignment with the Global Biodiversity Framework adopted in 2022.
In Michigan--and Washtenaw County in particular--expanding human populations and urbanization are likely to increase interactions with wildlife, such as coyotes, deer, and raccoons. These encounters could lead to conflicts, including property damage, crop losses, and threats to livestock, especially as wildlife habitats shrink or shift due to human activity.
- Washtenaw County could benefit from proactive measures, like habitat corridors and non-lethal wildlife management programs to reduce conflicts and promote coexistence. These efforts, alongside community engagement in conservation, could help balance urban growth with the preservation of local biodiversity, enhancing both human well-being and ecosystem health. (Source: https://news.umich.edu/human-wildlife-overlap-expected-to-increase-across-more-than-half-of-land-on-earth-by-2070/)
Transcription
David Fair: This is 89 one WEMU. And welcome to another edition of Issues of the Environment. I'm David Fair, and the U.S. Congressional Budget Office predicts population in the U.S. will grow from the present-day 342 million up to 383 million by the year 2054. And compared to other parts of the world, that's a relatively slow rate of growth. We've been looking at some research out of the University of Michigan School for Environment and Sustainability. Now, as a result, the research shows that more than half of all of the world's lands will see an increase in human-wildlife overlap by the year 2070. That means change is going to occur, and adaptation is going to be necessary. Our guest today is coauthor of the study. Dr. Neil Carter is associate professor in conservation science at the University of Michigan. And I appreciate your time, Dr. Carter!
Dr. Neil Carter: Thank you!
David Fair: This study was published in the journal Science Advances, and it looks at world population, as I mentioned, to the year 2070 and how that population growth will increase the overlap between humans and animals. The United Nations says there are 3.2 billion people in the world today. What do you project the global population to be in 2070?
Dr. Neil Carter: So, for the global population data, we're using something called the shared socioeconomic pathways, and they actually project different levels of human population size by 2070. But many of them are sort of topping out around 10 billion people. So, that's about 25% more people than there are currently.
David Fair: The study noted that population growth would result in more than a 70% increase in human-wildlife overlap in Africa and nearly 67% increase in South America. What are we looking at for an increase here in North America?
Dr. Neil Carter: We're going to see a little bit less than we're seeing there in Africa and South America. In North America, we're talking a little bit more like a third of the land area is going to see an increase. So still, a considerable amount of terrestrial land surface that will see an increase in human-wildlife overlap, but not nearly as much as two-thirds of the land area like you're seeing in Asia and Africa and South America.
David Fair: That has to amount to a significant loss of wildlife habitat. And I would imagine wildlife as well.
Dr. Neil Carter: Absolutely! So, one of the things that we're concerned about here is that we're sitting in the middle of a biodiversity loss crisis--as some people are calling it, the sixth major extinction event. It's largely human-induced. So, what we're interested in here is asking where you have people and wildlife overlap--and you're going to have some of those hotspots of interactions and overlap--are going to be the places that we should really have our eyes on, because those are places where those human activities, particularly habitat degradation, will have negative impacts on biodiversity. For this study, we were interested in a combination of factors. Not only were we looking at, well, where are people going to be moving to, but also how will climate change push species into different places? And so, we're interested in this confluence of those two forces. Species will have to adjust to changing temperatures and precipitation regimes around the world, and they'll have to shift their ranges. And likewise, people are going to be moving and changing their distributional patterns, and that's going to cause places that will free up from human pressure. Particularly in Europe, we're seeing that the continent where we expect to see places where people are actually leaving and the population sizes are decreasing, and you might have opportunities for rewilding species or opening up of areas where you have less encounters with people. But for the most part, as you pointed out, over half of the world's land is going to see an increase in human-wildlife overlap. And not just a little bit, but a lot.
David Fair: WEMU's Issues of the Environment conversation with Dr. Neil Carter continues. Dr. Carter is associate professor in conservation science at the University of Michigan School for Environment and Sustainability. I'm curious. Is the Midwest here in the United States going to be a hotspot for both people and animals to move as we deal with increasing the warm temperatures?
Dr. Neil Carter: Yeah. It looks like the Midwest is going to have some interesting patterns. In lower parts of Michigan, we're going to see a pattern that we saw in a lot of the globe--that is an increase in human populations and human densities. And we're going to see a poleward shift, a northward range of movements of many species as they're sort of tracking this climate change pattern. So, in other words, species that are here now--we may not see them in 50 years because they're simply going to be moving their ranges further north. So, while people are moving into the lower parts of Michigan and other parts of Wisconsin, the species are going to be leaving. So, that's one concern. Now, in parts of the upper Midwest, we might actually see some overlap occurring where both species' richness is increasing. New species are showing up from further south. And we're also going to have more people. So, those are definitely going to be some hotspots of overlap between wildlife and people. So certainly, a lot of variation and a lot of opportunity for increasing overlap and the Midwest and particularly in Michigan.
David Fair: I would imagine that when you have increased interaction between people and animals, that there are some real potential adverse effects, including an increase in the kinds of diseases that we see spreading through the area.
Dr. Neil Carter: Potentially. On one hand, yes. We should be thinking about some of those adverse effects. And it goes in both directions as you pointed out. The first direction and the one that we're very familiar with is adverse effects of people on wildlife. So, one of the things we're trying to highlight here is that the research is providing us some ideas of early warning signs or early warning areas of the world where we should be starting to focus our resources, where people are growing new cities. If there's going to be expansions of agricultural areas and we want to preserve the species that are there. We should start acting now. The other part of this or the other side of the coin is there are opportunities where you have a lot more overlap, and that will cause negative interactions, like the example of disease where we might have disease going from wild species into domestic, livestock species or from wild species to humans. And that's something that is, although rare, as we know, can be very impactful and, in some cases, catastrophic. And with that one that's front of mind being COVID-19 and other diseases that are emerging around the world that are zoonotic--basically from wild resources. So, that's something that we should be keeping our eyes on as we encroach into natural environments. There is a chance that we're going to be exposed to diseases that we wouldn't have been exposed to otherwise. But, honestly, I think that the things that I'm also interested in and thinking about is the positive relationships that we have with wildlife. I'm thinking about the Midwest, for example, and Michigan. Many, many people have very strong positive relationships with wildlife. It's part of what makes living here so enriching and fantastic. And so, we want to make sure to maximize those positive relationships. And that could also be the things that are like ecosystem services, including disease reduction. So, having some wildlife species here can actually help to keep diseases down, not actually exacerbate them, but actually make them better. So, for example, some carnivore species and those species will eat herbivore species and some of those herbivores are likely reservoirs for diseases that can pass over to domestic livestock. So, if you have a carnivore that's there, it can help reduce the prevalence of a disease in the herbivore population that could have been going into domestic livestock and impacting the whole industry. So, that's one way we're having species here. And intact healthy communities of wildlife is actually highly beneficial. So, that's something that I want to make sure that we think about in the future is how to preserve that species in the context of overlap, so that we can continue to get these really terrific benefits from having species in our backyards.
David Fair: In a way, it almost sounds like directing traffic. We're talking with Dr. Neil Carter from the University of Michigan on 89 one WEMU's Issues of the Environment. And with that in mind, what we're talking about is adaptation to a changing environment. So, as we look at global solutions, that's certainly a part of it. But perhaps more importantly is local policy and accommodation and how that plays into animal preservation and sustainability, right?
Dr. Neil Carter: Absolutely! Yeah, I mean, the question that starts to really come about is then how do we direct traffic? How do we direct the conservation resources and ways that we can minimize the adverse impacts to things like negative disease transmission to livestock or to people, or reducing the likelihood of a negative impact from carnivores on livestock or herbivores on crops? And instead, how do we maximize the benefits? How do we get more crops pollinated from species? How do we get species like insectivorous birds to continue to reduce crop pests? And how do we get all these benefits from living with wildlife that we know are there? How do we maximize those while, at the same time, minimizing the negative ones? And I think we're starting to see is that we're going to have to be a lot more creative in the sorts of tools and approaches that we bring to bear in communities and conserving species. And for example, in the past, we relied on a spatial planning approach where we set aside areas as protected. And for a long time, we had the luxury where we had places that were relatively free of human impacts. And we could essentially say, "Hey, leave that! Leave that as it is!" Those are getting much harder to find and will increasingly be harder to establish as the world gets more crowded with people. So now, we have to start thinking about how do we then accommodate human communities and in the conservation enterprise? And can we do so in ways that are inclusive of their different needs and expectations and priorities while also maintaining healthy ecosystems and intact wildlife communities? That's a challenge, but it's something that, as a conservation community, we're getting much, much better at. And the more that we can engage local communities in that process, I think the better we're going to be at doing so.
David Fair: It's interesting because we're talking about conservation. And, at the same time, the solutions seem to lay and engineering and urban planning. It's going to be a multifaceted approach. Are all these different and varied interests all on the same page as of yet?
Dr. Neil Carter: I think all of the varied interests understand the value of preserving ecosystems, preserving species and biodiversity. Whether or not that there are incentives for those different sectors to put resources into that, I'm not sure. I would suspect that perhaps not, and I would like for that to be something that happens in the future where we could harmonize our incentives, take advantage of a growing international awareness and mobilize the energy happening on a global scale to conserve biodiversity in an uncertain future. Because I think that most stakeholders--most industries--are aware of the tremendous benefits that we get from having healthy ecosystems and in biodiversity in place.
David Fair: So, where do you take the research from here? What comes next?
Dr. Neil Carter: Now, I think we need to drill down to some of these locations and case studies and local areas and really start to interrogate the ways that these interactions and overlap do lead to positive and negative interactions and outcomes for both wildlife and people. Earlier, you brought up the example of Michigan in the upper Midwest. That would be a fantastic place to drill down and start to ask, "Well, what are some of the benefits to having an active reserve species are? Can we quantify those and maybe even look at the ratio of the risks of having certain species around to the benefits?" And I suspect what we'll find is that, oftentimes, there are going to be net benefits. And if we can start to better articulate those, quantify those, visualize them and get them to different stakeholders in different communities' hands, we can make a much stronger case for our continued conservation of biodiversity.
David Fair: Can the research keep pace with the ever-changing climate and environment?
Dr. Neil Carter: I think the research has to, and I don't see it any other way. But I also think that research can only do so much. I think that, at some point, there needs to be a strong policy signal from municipal, local, state and federal that acknowledges where we are in terms of the world and the fact that we're going to get more crowded and it's going to get more complicated. And so, we should start consolidating resources now and thinking about how we're going to allocate those with a long-term vision. And the research will continue to help. But I don't want us to get bogged down with waiting for the research to help find things. I think we know enough now to know that having really intact, biodiverse places makes everybody healthier. Everybody is more well-off. So, we should continue to prioritize that.
David Fair: Well, Dr. Carter, thank you for taking the time to talk with me today! A fascinating conversation! And I look forward to the opportunity to the next conversation!
Dr. Neil Carter: Thank you so much for having me!
David Fair: That is Dr. Neil Carter, associate professor of conservation science at the University of Michigan School for Environment and Sustainability and coauthor of a research study on projected human-wildlife overlap as the global population continues to expand. It was published in the journal Science Advances. For more information, stop by our website at wemu.org. Issues of the Environment is produced with support from the office of the Washtenaw County Water Resources Commissioner. And you hear it every Wednesday. I'm David Fair, and this is your community NPR station, 89 one WEMU FM, Ypsilanti.
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