JWM: Problem crocs in Darwin, Australia come from far and wide

Darwin Harbor has had a crocodile problem since the city was founded.

Northern Australia’s biggest city sits smack dab in the middle of an assortment of reserves, national parks and other wild areas filled with waterways and wetlands perfect for saltwater crocodiles.

As a result, the Northern Territory government traps and removes an average of 250-300 crocodiles per year from the beaches and waters of Darwin Harbor in an effort to limit the risk of attacks on humans in the area. But the effort is labor-intensive and costly.

Yusuke Fukuda, a researcher with the Northern Territory’s Department of Environment, Parks and Water Security, wanted to find out a way to stymie the numbers of crocs that reached the waters around the city by finding the source of their population.

Credit: Yusuke Fukuda

Fast recovery

Saltwater crocodiles (Crocodylus porosus) were hunted to near extinction in some parts of Australia in the early 1900s. After the Australian government put protections on the species in 1970, the crocodile numbers in the Northern Territory grew from about 3,000 to more than 100,000 now. “For a big animal, they’ve bounced back fairly spectacularly in terms of numbers,” said Sam Banks, director of the Research Institute for the Environment and Livelihoods at Charles Darwin University in Darwin, Australia.

They’ve done so well that the fashion industry now takes some of the eggs from the wild to raise and harvest the animals and produce crocodile skin boots, handbags and other goods. Banks, Fukuda and their colleagues wondered whether they could direct these harvesting efforts to certain areas that produced many of the crocodiles that cause human-wildlife conflict in the city.

Credit: Yusuke Fukuda

In a study published recently in the Journal of Wildlife Management, between 2015 and 2017, they began taking tissue samples from crocodiles removed from Darwin Harbor. The researchers analyzed the DNA and compared it with samples from eggs and live crocodiles from all around northern Australia, Papua New Guinea, East Timor, Cambodia, Indonesia, Malaysia, New Caledonia, Singapore and Vietnam.

“Basically, every time we get a crocodile in Darwin Harbor, we can pinpoint the genetic origin of that animal,” Banks said.

Credit: Yusuke Fukuda

The source of the problem

The analysis revealed there were no international travelers, but the crocodiles didn’t just come from one or two small source populations. “They definitely all came from the Northern Territory of Australia,” Banks said.

Credit: Yusuke Fukuda

Most of them come from places within 100-200 kilometers of Darwin, like Kakadu National Park. Some even came from much farther away, like Arnhem Land—one may have swum 700 kilometers to reach Darwin.

“They do move pretty widely,” Banks said.

Credit: Yusuke Fukuda

Some crocodiles that reach Darwin Harbor are large—the biggest male among those the team tested was more than 4 meters long. But most are much smaller, in the 1- to 2.5-meter range. Banks said that most of these are likely subadults that get pushed out of their natal lands.

“Crocodiles have recovered so well that it’s probably fairly difficult for young crocodiles to find new territory,” Banks said, adding that some may just bounce along the coast until they find Darwin Harbor.

In some ways, the removal of crocodiles is probably what’s making Darwin Harbor so appealing, as it seems like the perfect place to settle down for these itinerant young crocs. It always seems like a great place since it’s free of big, older crocs. “But it’s kind of a trap,” Banks said, since wildlife managers remove them whenever they find them.

Credit: Yusuke Fukuda

The findings suggest that targeting source populations for extra egg harvesting won’t be an easy way to stop the source of young crocodiles leaving home and moving to Darwin, simply because there are so many sources over such a wide area. “The current strategy of managing problem crocodiles when they arrive in Darwin, combined with an intensive public awareness campaign, will remain the most effective strategy for now,” Banks said.

The research did reveal some areas where the government could increase trapping efforts. Since half of the crocodiles came from rivers to the east of the city, “intercepting them closer to the eastern mouth of the harbor may be a strategy worth testing,” the authors concluded in the study.

Credit: Yusuke Fukuda

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.

Chronic wasting disease reaches Indiana

Chronic wasting disease has been detectWhited in a wild deer in Indiana—the last Midwestern state believed to be free of the disease. The infected deer was discovered in early April as part of a state program that works with taxidermists to help in sampling efforts, Outdoor Life reports.

Indiana Department of Natural Resources officials say the deer was harvested in the 2023 season by a hunter in LaGrange County, near the border with Michigan, where the fatal prion disease had been detected previously.

“We had done prior intensive surveillance in that area,” IDNR deer program lead and biologist Joe Caudell told Outdoor Life. “This is one of those areas that we were always keeping an eye on. We wanted to make sure we had taxidermists participating there, and when we got sick deer calls from that area we were always on a little bit higher alert, because of that proximity to Michigan.”

The prion disease is always fatal to cervids, including deer, elk and moose. It has been detected in 34 states and four provinces.

Read more from Outdoor Life.

As deer shift northward, caribou decline

As the climate changes, white-tailed deer are shifting northward into western Canada’s boreal forest. But what’s good for deer isn’t necessarily good for caribou.

“The expansion of white-tailed deer into the boreal forest has been linked to caribou declines,” said Melanie Dickie, a doctoral student with the University of British Columbia’s Okanagan’s Wildlife Restoration Ecology Lab.

In a study published in Global Change Biology, researchers looked at the northward movement of white-tailed deer (Odocoileus virginianus) as climate change creates milder winters and forestry and energy exploration create new food sources for deer. They found that the expansion is uprooting existing predator-prey dynamics, creating concerns for species like the threatened woodland caribou (Rangifer tarandus caribou).

The incursion of deer is accompanied by rising numbers of gray wolves (Canis lupus). The wolves also prey on caribou, which conservationists are trying to recover.

“Deer can handle high predation rates, but caribou cannot,” Dickie said.

Read more from the University of British Columbia.

TWS comments on utility-scale solar installations

The Wildlife Society recently recommended the Bureau of Land Management employ the best available science to minimize negative effects on wildlife from utility-scale solar energy developments.

This suggestion was part of a comprehensive set of comments to the Bureau of Land Management regarding the draft Programmatic Environmental Impact Statement (PEIS) for Utility-Scale Solar Energy Development.

Comments were developed in coordination with—and later co-signed by—a number of TWS sections and chapters, as well as TWS’ Renewable Energy Working Group. The comments highlight the importance of TWS’ Conservation Affairs Network in leveraging the expertise of TWS’ members in the organization’s federal policy engagement. Through this network, members from affected units and relevant working groups coordinated to establish the scope and framework of TWS’ comments to the BLM.

The BLM’s PEIS aims to update the 2012 Western Solar Plan, as mandated by Executive Order 14008 and the Energy Act of 2020. This legislative framework sets ambitious targets, including a goal of 25 gigawatts of electricity from wind, solar and geothermal projects on public lands by 2025. Originally covering six southwestern states—Arizona, California, Colorado, Nevada, New Mexico and Utah—the plan’s scope is now under consideration for expansion to also include Idaho, Montana, Oregon, Washington and Wyoming. This expansion reflects the evolving landscape of renewable energy development and emphasizes the need for comprehensive and local engagement to guide such endeavors.

 In its comments, TWS emphasized the importance of using the best available data to inform siting decisions for utility-scale solar energy development. The PEIS as written, relies on existing resource management plans that are, in some cases, significantly out of date. By leveraging the most up-to-date scientific information and research findings, the BLM can make informed choices that minimize negative impacts on wildlife and its habitats while maximizing the efficacy of renewable energy projects.

Additionally, TWS recommended prioritizing the siting of utility-scale solar installations on previously disturbed lands and areas close to existing transmission infrastructure. This strategic approach not only minimizes further habitat destruction but also maximizes the efficiency of energy transmission, thereby reducing the overall ecological footprint of renewable energy projects.

TWS urged a holistic approach that considers the potential impacts on all wildlife, regardless of federal listing status. This included recommendations to consider the needs of species of greatest conservation need, at-risk wildlife, and birds of conservation concern. This approach would ensure that planning efforts are comprehensive and effective in safeguarding biodiversity and ecological resilience in the face of renewable energy development pressures.

Moreover, TWS emphasized the importance of recognizing and mitigating the indirect impacts of solar installations on wildlife behavior and migration patterns. Comments specifically recommended introducing a science-based buffer around exclusion areas in the PEIS to account for avoidance of and attraction to solar facilities on the landscape. By integrating design features that minimize disturbances and implementing adaptive management strategies, the BLM can mitigate long-term impacts on wildlife populations and their habitats.

Collaboration is central to The Wildlife Society’s advocacy efforts. Through the Conservation Affairs Network, participants emphasized the locally relevant impacts of the PEIS and provided crucial data and peer-reviewed literature to strengthen the final comments. The comments were co-signed by TWS’ Western and Southwest Sections, Montana, Nevada, New Mexico, Oregon, and Sacremento-Shasta Chapters, and Renewable Energy Working Group.

WSB: Study tests accuracy of thermal drone surveys

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

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  

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?

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

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

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.