WSB: Study tests accuracy of thermal drone surveys

April 26, 2024 by David Frey

More and more biologists are turning to drones to survey wildlife on the landscape. By using thermal cameras, they can even find animals they might miss with the naked eye.

But a bird’s-eye view doesn’t mean the cameras will catch everything, and even thermal imagery has its downsides.

“There are trade-offs associated with each survey method,” said TWS member Aaron Foley, assistant professor for research with the East Foundation and the Caesar Kleberg Wildlife Research Institute.

In a study published in the Wildlife Society Bulletin, Foley and his colleagues evaluated the accuracy of daytime thermal-based drone surveys compared to helicopter, spotlight and trail camera surveys.

Helicopters and airplanes are the typical go-to vehicles for aerial surveys, but they can be dangerous for the crews and expensive for wildlife agencies. They can also be inaccurate and highly variable. In one study, Foley said, helicopter surveys detected anywhere from 20% to 70% of marked white-tailed deer (Odocoileus virginianus) on rangelands.

“We wanted to evaluate whether drones could generate more consistent population estimates,” he said.

Yet as drones emerge as an alternative, while studies around the world have looked at their feasibility, few have looked at their reliability.

That was a gap Foley’s team sought to address. Despite the advantages drones offer, their counts aren’t always accurate.

“There was a study from Australia that compared helicopter versus drone estimates of kangaroos,” Foley said. “The drone severely underestimated the kangaroo population size. If there was no independent population estimate via helicopter surveys, then one might erroneously conclude that the kangaroo population size was relatively low.”

To conduct their study, the researchers wanted specifically wanted to test the drone technology over a diversity of landscapes to see how well it performed in different terrains, areas with dense vegetation and open grasslands.

They tested the drones on five private, high-fenced ranches in South Texas, and surveyed a unique mix of native wildlife, domesticated animals and exotic species maintained for private hunts, from white-tailed deer to white-bearded wildebeest (Connochaetes taurinus mearnsi).

The researchers found a variety of factors that can influence the drones’ accuracy. Dense brush often blocked the view of animals on the ground. On one site, the drone was unable to follow the contours of the hills, resulting in a severe undercount in the brushy terrain. Even on flat grasslands, with little in the way to block the view, the reflectance of the sun on the landscape resulted in a hot background that made it hard for the thermal cameras to detect animals’ heat signatures.

But after accounting for visibility bias, the researchers found that the drones yielded population estimates for white-tailed deer similar to those from trail camera and helicopter surveys, and estimates from repeated drone surveys proved to be more consistent than those from helicopter surveys.

The findings suggest that drones can be reliable, the researchers found, but “some environments are more amenable to drone surveys compared to others.”

This article features research that was published in the Wildlife Society Bulletin, a TWS peer-reviewed, open-access journal. Join TWS now to access all TWS journals and read the latest in wildlife research.

Computer model explores Tribal use of fire for ecosystem health

April 26, 2024 by The Wildlife Society

Researchers are using 21st century technology to unveil traditional practices of fire stewardship.

Partnering with the Karuk Tribe, researchers from Oregon State University used a computer simulation model to understand how the Tribe historically used fire for ecosystem health.

Published in Ecological Applications, the findings show that before the arrival of European colonizers, cultural burning was extensive across the landscape, with an estimated 6,972 cultural ignitions occurring annually, averaging about 6.5 ignitions per year for each Indigenous fire steward.

The research focused on 1,000 square miles of Karuk Aboriginal Territory in the western Klamath Mountains of northern California. The mountains are part of a fire-prone ecosystem that historically had frequent fires of low or moderate severity but have recently experienced severe wildlfires.

Working with the Karuk Tribe Department of Natural Resources, OSU scientists developed historical estimates for cultural ignition locations, frequency and timing. Statistical parameters were collaboratively developed and honed with Tribal members and knowledge holders using interviews, historical and contemporary maps, ethnographies, recent ecological studies and generational knowledge.

“The information that went into this model is not new at all—it’s been held by Karuk Tribal members for millennia—but we developed new methods to bring the knowledge together and display it in a way that showcases the extent of Indigenous cultural stewardship across this landscape,” said Skye Greenler, who led the partnership when she was a graduate research fellow in the OSU College of Forestry. Read more from OSU

2024 TWS Elections: Southwest Representative  

April 25, 2024 by The Wildlife Society

The ballot for The Wildlife Society’s 2024 elections includes nominees for the position of Canadian Representative to TWS Council.

Electronic ballots will be sent May 29 to all members with an email address. Members without an email address will receive a paper ballot in the mail. Voting will close June 30. Mailed paper ballots must be postmarked on or before June 30. In accordance with TWS’ Bylaws, newly elected council members are scheduled to be installed at the next regular meeting of Council during the 31st Annual Conference, Oct. 19-23, in Baltimore, MD.

The candidates’ statements expressing their vision for The Wildlife Society and their interest in running for this council position are below.

NOMINEES FOR SOUTHWEST REPRESENTATIVE TO TWS COUNCIL

Kathy Granillo

I have been active in The Wildlife Society for over 30 years, with most of that time spent in the Southwest. The wildlands, wildlife and wildlife professionals of this area are near and dear to my heart. I am the current Southwest Representative to Council (2021-2024) and I am seeking a second term. I believe I have accomplished much in my first term and that it has prepared me to do even more in a second term. I am actively involved in crafting the new Strategic Plan for TWS and want to help implement that plan over the next few years. I have helped shape the future of TWS through my work on the Diversity Committee, the Position Statements Committee, and as Council Liaison to the IDEA Working Group and the Climate Change and Wildlife Working Group. I strive to represent the Southwest geographic area by attending and presenting at the Texas Chapter annual conferences, and the Joint annual meetings of the Arizona and New Mexico Chapters. I sit in on chapter and section board meetings and stay in touch with members via the various newsletters and through email and phone calls. My priorities include focusing on better communication between scientists and managers; involving youth and minorities in conservation and science, and encouraging wildlife professionals to stay engaged and educated about our rapidly changing world and the impacts on wildlife and the places they live.

Read Kathy Granillo’s complete biographical sketch here.

Erika Nowak

This is my first time running as a candidate for TWS SW Section Representative. I understand the workings of the Section fairly well by virtue of being your treasurer for the past few years and through my interactions with other board members. Truthfully, though, Kathy Granillo has much more experience with this position, and her long-standing support of the Section inspires me. I hope to learn from her until such time as she decides to leave the position. At that time, in addition to whatever the Section asks of me, I’d like to help the Section increase its support (logistical and financial) of international chapter members, for example by encouraging virtual and in-person attendance at regional and national meetings.

Read Erika Nowak’s complete biographical sketch here.

Can these butterflies fill the gap left by their extinct relative?

April 25, 2024 by The Wildlife Society

Biologists have released dozens of silvery blue butterflies in San Francisco in hopes that they can occupy in the niche once filled by their iconic but extinct predecessor.

The Xerces blue butterfly (Glaucopsyche xerces) disappeared in the 1940s as development carved into its habitat. Exploring the genetics of the long-lost pollinator, researchers found the silvery blue butterfly (G. lygdamus) is closely related and could help fill an ecological gap left by the Xerces blue’s disappearance.

“This isn’t a Jurassic Park-style de-extinction project, but it will have a major impact,” project leader Durrell Kapan, a senior research fellow for the California Academy of Sciences, said in a news release. “The silvery blue will act as an ecological ‘stand-in’ for the Xerces blue, performing the same ecosystem functions as both a pollinator and a critical member of the food web.”

Read more from SFGate.

Q&A: TEK and the wildlife profession

April 24, 2024 by David Frey

Long before TWS member Ty Werdel became trained in Western approaches to wildlife management, he was immersed in traditional approaches. Born on the Lake Traverse Reservation in northeastern South Dakota, he comes from a long line of Tribal citizens in the Turtle Mountain Band of Chippewa and the Sisseton Wahpeton Oyate.

“I grew up riding horseback, hunting, fishing, gathering and learning about the land and wildlife from being an active, consumptive participant of the ecosystem,” he said. “Listening to the stories from my older relatives, participating in traditional ecological practices and growing up in an agriculturally focused area shaped how I view our relationship with the natural world.”

Those experiences guided his interest in exploring wildlife management from both the perspectives of Western science and traditional ecological knowledge, known as TEK.

In a paper in the Journal of Wildlife Management, Werdel, an assistant professor in the Department of Rangeland, Wildlife, and Fisheries Management at Texas A&M University, and coauthors David Matarrita‐Cascante and Jacob Lucero, also of Texas A&M, discuss the state of TEK in the wildlife management profession.

“A conceptual piece like this was well outside of my comfort zone,” Werdel said. “[My coauthors] helped craft a coherent way to express the state of TEK in wildlife management as we see it.”

The paper traces a trajectory from “elitism” to “equity.” We caught up with Werdel to discuss the article and the growing interest of TEK in the wildlife profession.

A headshot of Ty Werdel. Courtesy: Ty Werdel

Do professionals need to do more to embrace TEK?

I think TEK is a hot topic right now, and the motivations behind embracing TEK are not always genuine but are yet to play out. If professionals are serious about holistic management of ecosystems that benefit flora, fauna and people, TEK can provide superior guidance on long-term sustainability and management, and professionals should seek to embrace TEK. Of course, this all depends on the willingness of holders of TEK to participate in relationships with outside professionals, and something to keep in mind—just because someone is a wildlife management professional does not mean they are entitled to TEK. If professionals are going to embrace TEK, they need to embrace authentic relationships with knowledge holders and Tribal communities. This is not a task that can be taken lightly.

What values does TEK bring that Western science misses?

TEK is place based, and regardless of how it is defined in any particular community, there is a relationship between the people and the environment that is necessary for sustaining the enduring coexistence of both. Historically, Western science practitioners have focused on understanding, sampling and managing short-term temporal fragments of an ecosystem, in which management does not necessarily provide benefits that extend through generations. Instead, holistic management that is informed by TEK can address long-term sustainability challenges and promote the wellbeing of ecosystems and communities over time.

How can Western science better incorporate TEK?

The term “incorporate” implies taking in or containing something as part of a whole. However, TEK and local ecosystem stewardship have endured since time immemorial, independent of Western science. Western scientists should aim to create relationships with knowledge holders, benefiting both Tribal communities and our understanding of the environment. This approach recognizes the enduring value of TEK and promotes respectful collaboration, bridging the gap between scientific knowledge and TEK for more holistic environmental management.

Your timeline begins with a period of elitism. Are there still traces of that?

Absolutely! There’s observed elitism, whether you are talking about the number of degrees someone has, or the validity of different knowledge systems. But I think, in general, people within the wildlife management profession are open-minded and will look to the benefits of learning about how TEK can be used in the application of wildlife management.

You warn that Western science’s interest in TEK now brings a risk of exploitation. Can you talk about those concerns?

As a tenure track assistant professor, I am familiar with the pressures of securing funding and publishing articles. A common strategy for some academics to achieve those goals is to “follow the money.” With funding agencies now including favorable reviews of proposals that include TEK-related work (which by itself can be a positive thing), everyone seems to be in a rush to capitalize on this trend. It is unfortunate, but the truth is that oftentimes TEK is used as a facade by Western scientists to generate publications or solicit funding without any service, reciprocity or credit to Tribal communities. This exploitation is often coupled with a lack of effort to truly understand what meaningful collaboration with Tribal communities entails. Instances where Western scientists assume entitlement to knowledge from Indigenous communities without reciprocal benefits are ethically irresponsible and unfortunately common.

Your final stage is equity. What will it take to get there?

It will take a lot of effort from both established and up-and-coming wildlife professionals. Achieving equity will require policy support, institutional commitments, meaningful community engagement, education and training on Indigenous issues, and accountability measures. Prioritizing the inclusion of TEK in wildlife management curricula is a good first step to promote future collaboration with Indigenous communities, provide equitable participation in research and integrate Indigenous knowledge in a way that is respectful, valued and beneficial for all stakeholders involved.

This article features research that was published in a TWS peer-reviewed journal. Individual online access to all TWS journal articles is a benefit of membership. Join TWS now to read the latest in wildlife research.

History may point to a brighter future for Canada lynx

April 24, 2024 by The Wildlife Society

Canada lynx once roamed a much broader range in the U.S., researchers found, and some places they once existed may help them weather a changing climate.

In a study published in Biological Conservation, researchers found that lynx (Lynx canadensis) may do well in parts of Utah, central Idaho and the Yellowstone National Park region, even considering climate change and the lack of lynx in those areas now.

Lynx currently inhabit limited, northern portions of Washington, Idaho, Montana, Minnesota and Maine. Recovery plans for the species have been based on assumptions that they were never found much beyond these areas in the U.S.

Using a model validated by historical records, researchers found that in 1900, Canada lynx roamed a much larger area throughout the Pacific Northwest, Rocky Mountains, Great Lakes region and parts of New England.

“History matters even for wildlife,” said lead author Dan Thornton, a Washington State University wildlife ecologist. “As part of the criteria for species recovery, we have to understand their historic distribution. Otherwise, how can we help recover a species, if we don’t know what we’re recovering to?”

Read more from WSU Insider.

New maps expand picture of big-game migrations in the West

April 23, 2024 by The Wildlife Society

A new set of maps explores the movements of ungulates throughout the American West, furthering scientific understanding of the geography of big-game migrations.

“Ungulate Migrations of the Western United States: Volume 4” is the latest in a collaborative U.S. Geological Survey report series. The volume documents 33 mule deer (Odocolieus hemionus), pronghorn (Antilocapra americana) and elk (Cervus canadensis) herd migrations in states ranging from Washington to New Mexico.  With this latest volume, the report series details the movements of 182 unique herds across 10 states.

“We’ve now mapped nearly two hundred migrations of mule deer, pronghorn, elk and other ungulates across diverse landscapes, from the high alpine Rocky Mountains to the temperate rainforest of the Pacific Northwest and the desert ecosystems of the American Southwest,” said TWS member Matt Kauffman, the report’s lead author and a wildlife biologist with the USGS Wyoming Cooperative Fish and Wildlife Research Unit at the University of Wyoming.

Ungulates migrate throughout the West each spring and fall to access the most nutritious plants and avoid deep snow. But as the human footprint in the West expands, these species increasingly face obstacles such as new subdivisions, energy development, impermeable fences and high-traffic roads on their long journeys. By mapping their migrations, scientists provide critical information—like where migrations overlap with existing and potential obstacles—to managers, policymakers, NGOs and private landowners working to minimize impacts on wildlife.

“To best conserve and protect the habitat used by migrating elk, mule deer, moose and pronghorn, we have to know exactly where these species move across the landscape,” said TWS member Blake Henning, chief conservation officer at the Rocky Mountain Elk Foundation. “That’s why this mapping work is so important—it’s to ensure their future health and well-being.”

Read more from the USGS. To explore migration routes and ranges, visit www.westernmigrations.net or download the map files from www.sciencebase.gov.

Deep snows deter red foxes

April 23, 2024 by Dana Kobilinsky

Big, one-off snowstorms in Maine driven by climate change could result in snow too deep for red foxes.

As smaller carnivores, red foxes (Vulpes vulpes) are affected by species across the food web, from fellow predators like coyotes (Canis latrans) to prey like snowshoe hares (Lepus americanus). “That makes them a good sentinel species,” said Andrew Butler, a PhD candidate at the University of New Hampshire. But, like other animals, they are also affected by conditions on the ground.

Butler led a study published in Ecosphere using camera traps to look at how the presence of coyotes and snowshoe hares related to red fox abundance, and what role snow depth may play.

Red foxes appeared to benefit from sharing the landscape with coyotes. Credit: University of Maine

The team combed through photos of martens (Martes americana), fishers (Pekania pennant) and black bears (Ursus americanus) in addition to their target species. “I think it really highlights how dynamic and complex that community is in northern New England,” he said.

Researchers expected that with more coyotes present, they would find fewer red foxes. Previous studies had found that coyotes prey on red foxes—not for food, but to eliminate competition. Instead, Butler’s team found that red foxes might benefit from sharing the landscape with coyotes by scavenging the leftovers on deer (Odocoileus virginianus) carcasses that coyotes left behind.

Snowshoe hares showed up in areas where there were no red foxes. Credit: University of Maine

Butler and his team also expected to see more foxes when there were more snowshoe hares, which past research found to be the foxes’ main food source in the winter. But his team actually found hares showing up in areas without red foxes. They think that has something to do with red foxes not being able to hunt in of the dense stands of young spruce that the hares occupy.

More than either predators or prey, however, it was snow depth that had the strongest relationship with red fox abundance. In the second and third years of the study, when snow depths topped one meter, there was less than a 20% probability the red foxes would colonize the site. That suggests climate change could be a mixed bag for red foxes in the state. “Overall, predictions are for less snowfall, which may allow foxes to expand,” Butler said. “But there’s also more predictions for more frequent, larger snow events.”

Can biodiversity boost mental health?

April 22, 2024 by The Wildlife Society

Biodiversity isn’t just good for the ecosystem. It may also be good for our mental health. In a recent study published in Scientific Reports, researchers found that spending time in places with a diverse range of natural features and species is associated with stronger improvements in our mental wellbeing compared to places with less diversity.

The citizen-science study used a smartphone application called Urban Mind to collect real-time reports on mental wellbeing and natural diversity from nearly 2000 participants. Researchers found that environments with a larger number of natural features, such as trees, birds, plants and waterways, were associated with greater mental wellbeing than environments with fewer features, and that these benefits can last for up to eight hours.

The results suggest a new way to think about urban parks, said lead author Ryan Hammoud, research assistant at the Institute of Psychiatry, Psychology & Neuroscience at King’s College London. “In practice, this means moving away from heavily curated monocultural pockets and parks of mown grass, which are typically associated with low biodiversity, towards spaces which mirror the biodiversity of natural ecosystems,” he said. “By showing how natural diversity boosts our mental wellbeing, we provide a compelling basis for how to create greener and healthier urban spaces.”

Read more from Science Daily.

When brown treesnakes don’t take the bait

April 22, 2024 by By Gail Keirn and Shane Siers, USDA Wildlife Services

In October 2020, a new population of invasive brown treesnakes was discovered on Cocos Island, a 33-hectare island located about 2.5 kilometers off the south coast of Guam. Cocos Island is a refuge for many lizards and birds, including endangered species, which were extirpated from mainland Guam by invasive predators including brown treesnakes (Boiga irregularis). Several tools and techniques, including baiting and trapping, have been developed and continue to be improved for managing invasive brown treesnakes on mainland Guam.

Researchers with the USDA Wildlife Services’ National Wildlife Research Center worked with WS operations employees in Guam and other partners to evaluate the usefulness of toxic baiting with acetaminophen-treated carrion baits and cage trapping on Cocos Island.

On this aerial view of Cocos Island, orange lines indicate the location of trails used for baiting and trapping. Credit: Maxar Intelligence

Multiple bait types and bait presentations—including bait put on the ground, suspended in the tree canopy and in four plastic-tube bait station configurations) were evaluated over more than 2,400 bait nights and 10,000 trap nights. All baits were monitored with time-lapse cameras. None of the baits were taken by brown treesnakes. During that time, only one brown treesnake was captured using a trap with a live mouse lure.

“For all practical purposes, baiting and trapping on Cocos Island are ineffective,” said NWRC researcher Dr. Shane Siers. “We know this low level of effectiveness is not a result of low snake density because of our visual searching and hand capturing efforts. We know the snakes are out there.”

A ground baiting set-up includes an infrared camera mounted directly over mouse bait. Credit: Shane Siers/USDA-Wildlife Services

Researchers hypothesize that the low success rates are due to an extremely high abundance of preferred live prey, primarily large geckos and birds. Future work on Cocos Island will include the continuation of visual searching and manual removal of snakes, the only method that has thus far been effective. Researchers also plan to evaluate whether the use of live bird lures may more effective than carrion or live rodents.

“These findings do not bode well for managing future island invasions by brown treesnakes. If snakes were to become established in other prey-rich environments, our current baiting and trapping methods may be similarly ineffective,” Siers said. “Preventing the accidental translocation of snakes from Guam remains a critical management strategy.” 

For more information, contact NWRC@usda.gov.

Wildlife Services is a Strategic Partner of TWS.