While researchers often focus on the effects of bird feeding on birds, what about the impacts of the activity on people? Some researchers argue that not only is it good for people, but it can also play a role in policy.
The team noticed that state agencies were advising people to stop feeding birds after a number of avian disease outbreaks in 2021. But these recommendations didn’t necessarily follow any evidence that bird feeding would increase disease spread, they found. What’s more, there wasn’t really a method of gauging if people were listening and how the guidelines impacted them.
Both the well-being of birds and of people need to be considered, the authors argue.
“The psychological benefits of bird feeding for humans are well-documented but often overlooked in management decisions in response to avian disease outbreaks,” they wrote in a study published in People and Nature.
“Ecological and social science need to be applied in tandem to ensure that well-intended guidance to cease feeding of birds does not have unintended consequences.”
Both bobcats and ocelots roam the thornscrub of southern Texas. But while the cats may look similar and have similar diets, their behavior in the moonlight can be very different.
As part of their research into how the two species use the landscape they share, Maksim Sergeyev, then a graduate student at the Caesar Kleberg Wildlife Research Institute, and his team looked at a variety of factors, from topography to temperature. Then they wondered how the phase of the moon affects these two predators, which rely on surprise to capture their prey.
“If you think about it, it’s very different at night when it’s a full moon and there’s a new moon,” Sergeyev said.
In a recent study published in PLOS ONE, Sergeyev and his colleagues collared eight ocelots (Leopardus pardalis) and 13 bobcats (Lynx rufus). They compared their habitat selection under the full moon and during a new moon from 2017 to 2021. What they found gave them new insight into how two species that seem so similar can behave very differently on the same landscape.
“It shed new light on how they share their space,” Sergeyev said.
Ocelots are federally endangered, primarily occupying rugged private lands in southern Texas. They rely almost exclusively on thornscrub landscapes to hunt and to take shelter from the Texas heat. Bobcats use the same landscapes, but they are more generalist, Sergeyev said, using the edges more than ocelots.
Ocelots are also highly nocturnal, while bobcats are more likely to hunt in the evening. As a result, researchers found, moonlight can mean very different things to them.
Ocelots, they discovered, didn’t change their habitat selection based on the phase of the moon, but they did change their movements. Under the full moon, they moved shorter distances. That may be because the bright moonlight blew their cover from predators. The darkness of new moons, however, allowed them to travel farther without being detected.
Bobcats, on the other hand, sought denser vegetation during full moons. That’s probably because they need more cover in the brightness. But their movement remained the same, regardless of the moon.
The findings could have conservation implications for ocelots.
“The biggest source of mortality for ocelots is vehicle collisions,” Sergeyev said. Since ocelots are more on the move on moonless nights, informing the public to be more cautious on dark nights could help the species persist.
After uncovering the reasons for the near-extinction of bison in Europe, researchers think they have some clues for successfully increasing populations there. Herds of European bison (Bison bonasus) used to roam Europe until 1927 when they became extinct in the wild. Since then, efforts to reestablish the species have resulted in 7,300 free-ranging bison, but those reintroductions were done without a good understanding of the species on the continent. In a study published in Proceedings of the Royal Society B Biological Sciences, scientists used fossil evidence, ancient DNA and modeling to determine what caused the European bison to initially decline. They found that environmental change and hunting by humans were the main causes. Using this information, they determined areas most suitable for the species today.
As Florida officials work to restore water levels in the Everglades, they wondered what effect it may have on bobcats there.
Biologists don’t know much about the big cats in the national park. But they did know they use tree islands—areas just a few inches higher in elevation than the surrounding wetlands. Those islands can support woody plants that don’t survive in the sawgrass waterways.
But as biologists explored bobcats in the national park, they found that invasive Burmese pythons (Python molarus bivittatus)—which are altering the Everglades’ ecosystem—potentially pose a greater threat to bobcats than changing water levels.
For a study published in the Journal of Wildlife Management, Katie Buckman, then a master’s student at Florida Atlantic University, and her colleagues set out to determine how bobcats (Lynx rufus) were using the tree islands in the Everglades. State biologists had seen them showing up in trail camera images, but they didn’t know much about the cats’ habitat use or response to fluctuating water levels.
The biologists were particularly interested in this topic, since plans called for restoring Everglades water levels to historical conditions. Diversions have siphoned water away from the “river of grass” for decades, transforming the unique ecosystem, while the construction of levees and highways have caused pooling of deep water in other areas.
“The Everglades need water,” Buckman said, yet no one knows how bobcats might respond to different water levels.
As Buckman and her team modeled habitat use for bobcats, though, they found little evidence that water levels affected bobcat habitat use, but the python invasion may be.
“The project started out looking at habitat use,” she said. “What ended up happening was, we couldn’t really ignore the Burmese python problem.”
Raised as pets and released into the wild, Burmese pythons have thrived in the Everglades, despite teams of python hunters dispatched to remove the voracious predators from the landscape. The constrictors eat the same small mammals that bobcats prey on, so as python numbers increase, they may create more competition for the cats.
As they created occupancy models, Buckman and her team expected that higher water levels would jeopardize bobcat numbers by limiting their access to tree islands, but that’s not what they found. Instead, they found that a wetter Everglades appeared to poselittle risk to bobcats, but the presence of pythons did.
Once pythons reached a density of more than three per square kilometer, “bobcat occupancy was significantly diminished,” researchers wrote in their study.
“Our results suggest that while hydrologic dynamics may play a role,” they concluded, “the invasive Burmese python has stronger influences on bobcat occupancy of tree islands in this Everglades conservation area.”
It was a bit of a surprise, Buckman said. Bobcats are highly adaptable, but invasive pythons are tough competitors.
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It’s well known that free-ranging cats eat lots of birds and rodents. But researchers recently documented cats around the world eating 2,000 species, including reptiles, mammals, even a number of insects, like monarch butterflies (Danaus plexippus) and emperor dragonflies (Anax imperator). Even more surprising, the study in Nature Communications uncovered evidence of cats scavenging species such as camels, cows and endangered green sea turtle (Chelonia mydas) hatchlings. The researchers’ findings came from a search of published and unpublished literature on cat predation.
“Domestic cats (Felis catus) are beloved companions for many people, but they are also invasive predators that have been linked to numerous birds, mammals and reptiles going extinct,” said Andrew Mitchinson, an editor at the journal Nature, in a related article.
Conserving rare species is difficult when they’re too elusive for standard data analysis methods. Researchers wondered if by taking information from species we do know something about, we can help out those rarer individuals through a process of integrating data for multiple species simultaneously with “integrated community models”—a sort of “Robin Hood” approach. The team published a paper in the Journal of Animal Ecology highlighting a framework where something like this could be put into effect.
We caught up with TWS member Elise Zipkin, an associate professor in the department of integrative biology and the ecology, evolution, and behavior program at Michigan State University who led the study, to find out more about the approach. Her responses are edited for brevity and style.
How did you come up with this “Robin Hood” idea for conservation?
The idea is built out of two streams of research that have happened over the last 10 to 20 years.
The first idea is what we call hierarchical community modeling. In this approach, you have a single data source, or a single way that you’re collecting data. But by using these approaches to collect data on one species, you can naturally collect data on the whole community. For example, with bird point counts, you can hear all the breeding birds in the area. Another example is walking transects and turning over rocks to find salamanders but finding other species along the way. Instead of analyzing each of those species, from that single dataset, on its own—and if we did that, we ended up having to throw out a bunch of rare species and only get the common ones— we can model them all together. This allows us to understand what’s going on with rare and elusive species and ultimately, developing conservation approaches for the whole community.
At the same time, there’s an approach we call data integration, or integrated modeling. In this framework, you have a single target species for which you are able to collect multiple different types of data. This is often done with many types of migratory bird species. For example, maybe you have banding data on bird species collected over years at a breeding ground. Maybe you also have count data on adults or productivity data on nest success. The idea of integrated modeling is to combine all the different data sources into a single model, and that leads to like a more complete picture of what’s going on for that target species.
My lab thinks that both of these frameworks are really cool and opening up many doors in conservation. And then we thought, let’s see if we can do a data integration approach for multiple species simultaneously. That’s where integrated community models come in. If you can learn a lot more about each of the individual species, you can learn a lot more about the community as a whole.
What are some concrete examples?
With butterflies in the Midwest, we’re trying to understand, are they increasing? Decreasing? What’s going on? It turns out the Midwest has the highest density of butterfly surveys of basically anywhere in the world, so it’s a really good opportunity to apply the integrated community modeling framework. There are about six multi-species datasets collected in various parts of the Midwest, all with slightly different protocols. There’s been some work on individual species, including monarch butterflies, but not so much with the whole community beyond a limited spatial extent. We especially want to know something about the trends of rare species. And we want to know what’s going on broadly with butterflies across space. We’re currently working on taking all the data on hundreds of butterfly species, and we’re going to integrate that together into this framework. That’s going to allow us to see what’s going on for some of these rare species that we just don’t have that much data on. Our hope is to see which counties across the Midwest might be the best for targeted conservation actions.
We also have been working with different kinds of bird data, like eBird, NEON, the Breeding Bird Survey, and national park monitoring data. Each of these monitoring programs sample different parts of bird habitats. For example, because the BBS is all roadside surveys, what we see with birds on BBS transects might be different than what’s happening in natural, protected areas, where NEON data are collected. If we integrate these data, we can get a more nuanced look of how species are doing across space and time.
Researchers demonstrated their “Robin Hood” approach using data on butterflies in the Midwest. Credit: David Pavlik
What is the next step in getting this framework out to people to use for conservation and management?
We still need more research, as the integrated community modeling framework is pretty new. We need to understand when and where these methods work well and where they don’t. What are the strengths of this approach? What are the limitations? When will this approach be beneficial and when will it not be all that helpful? I think we’re still a bit away from broader implementation, but hopefully that would be down the road.
What is your vision for this framework to be used in the future?
What would be amazing is if we could develop more general purpose software. We could have practitioners and managers being able to use integrated community models in a way that they don’t need to do all the coding themselves.
Elise Zipkin. Credit: Michigan State University
There’s this focus on single species management, largely because of past policies and regulations. But we’re in this huge biodiversity crisis where we need to be thinking broader about how to protect communities of species. The integrated community modeling framework still allows us to pull out individual species that we’re really concerned about, but it also provides an overall picture of what’s going on with a community—how the community is responding to environmental variables, as a whole. This will allow us to start to understand what might be the best management and conservation actions for lots of species simultaneously.
A common method scientists use to predict how tree species will respond to climate change may not be as accurate as they had thought. The method, called space-for-time substitution, assumes that tree species growing at the hotter end of their range can be an example of what will happen to populations at cooler locations under a warming climate. But researchers found that wasn’t true for ponderosa pine. They measured tree rings across the western U.S. dating as far back as 1900. Then, they compared the trees’ actual growth to what the model predicted would happen under climate change. “We found that space-for-time substitution generates predictions that are wrong in terms of whether the response to warming is a positive or negative one,” said Margaret Evans, a coauthor on the paper and an associate professor in the University of Arizona Laboratory of Tree-Ring Research. “This method says that ponderosa pines should benefit from warming, but they actually suffer with warming. This is dangerously misleading.”
The U.S. government is embarking on a first-ever effort to gauge changes in nature in the country, amid a warming climate, growing urbanization and other factors that are transforming the natural world.
As they set out on this National Nature Assessment, officials are seeking insights from people who have witnessed these shifts happen on the ground. That includes experienced professionals with decades of datasets, young people with an eye on the future, Indigenous knowledge holders and others who have watched the natural world around them change.
“The reality is, we just don’t have a full picture of what’s happening with nature across the U.S.,” said Phil Levin, the assessment’s director, in an online presentation to NOAA Fisheries staff.
A former senior scientist at NOAA Fisheries, Levin is a professor of practice in environmental and forest sciences at the University of Washington and a lead scientist at The Nature Conservancy in Washington state. He is “on loan,” he told NOAA Fisheries, to the White House Office of Science and Technology Policy to steer the project.
“We don’t fully understand how nature is changing in the future for our children and our children’s children,” he said. “That’s really the genesis for the first-ever National Nature Assessment.”
The NNA is intended to be an interdisciplinary effort to understand the role that nature—in many forms— plays in people’s lives and how natural systems are changing. A final report is expected to be released in 2026, with dozens of authors and contributors lending their expertise to a variety of topics:
Assessment approach of NNA1
The Status, Trends and Future Projections of Nature in the U.S.
Status, Trends and Future Projections of Drivers of Change of Nature in the U.S.
Nature and Equity
Nature and Human Health and Wellbeing
Nature and Its Relationship to Cultural Heritage
Nature and Safety and Security
Nature and the Economy
The project is seeking experts in fields ranging from conservation biology to environmental social science to environmental justice. A November notice in the Federal Register asks for nominations by Jan. 4.
“That’s really the engine of this whole assessment—the many, many authors from agencies and academia and beyond,” Levin said.
The effort followed an executive order by the Biden administration commemorating Earth Day 2022, which called for an assessment of the state of nature in the U.S. It’s being led by the U.S. Global Change Research Program, best known for its National Climate Assessment, a periodic report to Congress on the effects of climate change in the country.
In addition to its scientific components, Levin intends to include success stories and accounts from people in their own words.
“It is an assessment that is not just a compilation of data and trends but really focused on what are the needs of people,” Levin said.
Reindeer don’t need Rudolph to find their way at night. Researchers found that the ungulates can see light in the ultraviolet spectrum, aiding their ability to find food in the dark Arctic winter.
“Reindeer are so cool, but many people think about them only at Christmas,” said Dartmouth professor Nathaniel Dominy, first author of a recent study in the journal i-Perception.
Reindeer—known as caribou (Rangifer tarandus) in the North American wild—subsist primarily on a lichen known as reindeer moss, or Cladonia rangiferina. To the human eye, the white lichen is nearly invisible against the snow. But reindeer moss and a few other lichen species they eat absorb UV light. Using spectral data from the lichen and light filters calibrated to mimic reindeer vision, researchers found that these lichen appear as dark patches against a bright background.
“Getting a visual approximation of how reindeer might see the world is something other studies haven’t done before,” Dominy said.
Sri Lankan farmers seeking to keep elephants from raiding their crops are focusing on a unique trait in the animals: their dislike for orange trees.
The practice works so well that The Sri Lanka Wildlife Conservation Society conducted the so-called Project Orange Elephant, that’s goal is to deter elephants crop raids by planting the fruit around farming communities.
But these trees aren’t always easy to acquire or grow based on labor required, maintenance of the plants, space and other factors. As a result, Jorge Esparza, an undergraduate student in wildlife ecology and conservation at the University of Nevada, Reno, is seeking out other plants found in Sri Lanka that may help repel the animals.
“There are definitely plants that the elephants don’t like to eat that could serve as alternatives to the Project Orange Elephant,” Esparza said.
Jorge Esparza in front of his poster at The Wildlife Society’s 2023 Annual Conference in Louisville. Credit: Joshua Rapp Learn
Conflict between humans and Asian elephants (Elephas maximus) is an issue in Sri Lanka, which has one of the densest populations of these large mammals in the world. Killing elephants is banned in the South Asian country, but it still occurs as farmers perceive the animals as threats to their crops and livelihood—elephants can destroy entire crops in a single night.
Previous research and practice have revealed that planting orange trees around crops or farming communities keeps elephants away. They don’t like the taste of oranges—the Bibile Sweet (Citrus sinensis) variety is the one often used for this purpose—and the smell of the fruit can mask the aroma of the food they do like, such as rice, bananas, jackfruit and other popular crops in the area, Esparza said. Plus, the fruit can provide an additional source of revenue to farmers.
Students from the University of Nevada, Reno, and volunteers and staff from the Sri Lanka Wildlife Conservation Society interviewed locals about recent crop raids. Credit: Seth Freedman-Peel
Esparza conducted a least cost path analysis around Wasgamuwa National Park. This essentially meant predicting where elephants were most likely to move. He compared these areas to the locations of confirmed elephant sightings to predict areas with a higher probability of conflict.
An elephant in the kind of tall grass ecosystems that they often favor. Credit: Seth Freedman-Peel
The students and researchers created 50 by 50-meter plots, some in forests and others in more open areas. Esparza and his colleagues also interviewed locals to learn more about the impacts of human-elephant conflict on farmers. This included finding out more about which plants elephants didn’t like, such as coffee and sesame.Esparza surveyed the plants in these plots, paying attention to the presence of any of the plants they didn’t like.
Comparing elephant movements to places they avoided revealed more plants the animals may dislike—species like African mahogany and Dimorphocalyx glabellus, a small tree native to the country.
Esparza said that this knowledge can improve the options farmers have for repelling elephants from farmland. Learning more about these ecological relationships may offer ways to decrease human-elephant conflict in a country where it is a pressing issue.
