EXPERT Q&A
Study: Tracking individual animals can reveal the mechanisms of species loss (DOI: 10.1016/j.tree.2024.09.008) (available when embargo lifts or by request)
Today's ecologists have more data than ever before to help monitor and understand the world's biodiversity. Yet researchers are still working to get more detailed information to better combat declining animal populations that can eventually lead to species extinctions, says animal ecologist Scott Yanco of the University of Michigan.
Yanco, a research fellow at the U-M School for Environment and Sustainability, believes that change is on the horizon thanks to advances in animal tracking technology. Researchers affix these devices to individual animals to monitor their locations and other information over time. With these technologies, scientists are accumulating more detailed information throughout the lives of individual animals to understand the specific impacts of threats like pollution, climate change, and habitat loss and fragmentation.
Working with U-M evolutionary ecologist Brian Weeks and an international team, Yanco authored a new study highlighting the opportunity for animal tracking data to help usher in a new era of conservation.
Why is it important to study biodiversity?
Biodiversity-and the health of our biosphere more generally-is essential for human prosperity and well-being. Our biosphere is the basis by which we get our food, by which we get our water, by which we have the air to breathe. It is also the basis for much of our recreational activities and even wide swathes of our economy. Our biosphere is the foundation upon which human society is built.
Often when we think of biodiverse places, we picture a rainforest in the Amazon or Southeast Asia-which are biodiverse, to be sure-but the biodiversity in your backyard matters, too.
Understanding what mechanisms are governing biodiversity is absolutely essential for us to develop policy and management and conservation actions so that we can try and prevent or mitigate the next pandemic, so that we can make sure that our crops are not subject to catastrophic failure, so that we can make sure that we're all drinking clean water and breathing clean air, and that we all have beautiful, restorative and important places to go and recreate and enjoy. Biodiversity is something that everybody should care about, even if they don't care about biodiversity.
Can you share a brief history of how we've used animal tracking to monitor different species?
An animal tracking device is any device that we can put on an animal that allows us to record its position in time and space. Traditionally, we've done that by outfitting animals with simple markers. With birds, we use leg bands-most commonly little aluminum rings that we attach to their legs with a unique code. With mammals, we use things like collars and ear tags.
However, to observe these individuals over time often requires finding and observing these animals multiple times, or even possibly even trying to recapture them multiple times. Having to recapture animals every single time we need to know their location means that we don't actually get information about them very often because doing so is time consuming, difficult work. As a result, the resolution of our data is quite coarse and it's hard to see things that are happening over short time scales.
More recently, there has been an absolute explosion in miniature electronic devices that can record an animal's location. Much like the GPS built into your cell phone, these devices give us highly precise information about where an animal is on the planet and, increasingly, what it is doing. These new devices have created an avalanche of data revealing new details about the incredible movements animals are making and showing us the complex ways they interact with their environments. For many species, we can now do this sort of tracking over global extents and for long periods of time.
These new tools create a unique opportunity to study not just animal behavior, but also the processes that affect things like reproduction or mortality-exactly the types of things we need to know if we want to understand what is driving the global loss of biodiversity.
How can animal tracking be used to address biodiversity loss?
We do a decent job of monitoring population levels for many species-in many cases, we know when populations go up and down. What we're missing about these species are the specifics causes that lead these populations to go up and down. And by causes, I don't mean general understandings like, "Climate change is bad for Species X." Rather, precisely how does that process work-what exactly is climate change doing? Is there a place where we can intervene?
For example, it's one thing to say, "Habitat fragmentation did it." But it's more informative if we can say, "Habitat fragmentation in this one place puts animals into a body condition that makes them less likely to survive migration, and that results in mortalities in a specific area." In that case, we have a whole chain of events that we can look at and use to design on-the-ground interventions that can make a difference for that species.
We know at a broad scale that things like disease, pollution, invasive species, climate change, habitat loss, direct exploitation, or harvesting animals, have an impact. But we can't just say, "Stop doing all that." Instead we need to find ways to make targeted recommendations that we know will have a positive effect on wildlife populations. By getting really detailed information about the exact drivers of population declines, we can be very specific about how we might modify human activities to reverse those declines. Doing it that way might allow us to achieve conservation outcomes while minimizing the impact to humans-that's a win-win for all parties.
Because animal tracking gives us such a detailed view into animals' lives, we have this new opportunity to generate exactly the sort of insights we so desperately need. It allows us to study species that were previously hard to observe, to track outcomes over huge parts of the globe and to do so with incredible precision.
What are some of the modern and emerging animal tracking technologies you're excited about?
The ones that we all love to work with-if our study system or species can support them-are GPS units just like in your telephone. They can sometimes even use cell networks or satellites to send the data to us without researchers ever needing to relocate the animal. Now, if you're putting a device like this on an elk or an elephant, it doesn't need to be much smaller than your telephone. But we always try to minimize how much weight we put on an animal and, as the animals get smaller, the devices we use need to be miniaturized.
For the kinds of birds that I often work with, they're simply too light to carry that kind of GPS package. So we're working with tags that can record data, but can't always send it to us and that's a really active area in development-and there are many emerging solutions to this problem. One example is a system called ICARUS that's moving toward smaller tags and using space-based satellites for data uploads.
Increasingly, we also see auxiliary sensors included with these trackers, with which we can measure other things like temperature, relative humidity and air pressure. There are mortality switches that can send a signal when it thinks the animal has been motionless for too long and maybe has died. There are tags that you can implant into deer and elk to understand if they've given birth.
For example, I have a new paper where one of my collaborators surgically implanted a heart rate monitor and a body temperature monitor inside these little blackbirds. We could measure their heart rate every 30 minutes for almost a whole year and understand the dynamics of how much energy they were spending, how they prepared for migration, and how they thermoregulated in different environments.
There has really been a tremendous explosion in the types of technologies that we've been seeing. And, again, this level of detail gives us a new way to understand how human activities are contributing to species extinctions so that we can reverse those processes.
