Nature Signals Podcast

Sea otters are one of the Pacific Ocean's most beloved animals, but new research suggests they face a growing threat from PFAS, also called ‘forever chemicals.’ In this episode, we explore a study that found every sea otter examined by biologists along the coast of British Columbia contained PFAS contamination, with the highest concentrations detected in animals found near urban areas and busy shipping lanes.

We explain why sea otters are much more than charismatic marine mammals. As a keystone species, they help control sea urchin populations, allowing kelp forests to flourish. Those underwater forests provide habitat for countless marine species, su pport fisheries, reduce coastal erosion and capture significant amounts of carbon. Scientists are concerned that if PFAS pollution weakens sea otter populations, the entire coastal ecosystem could be affected.

The episode also examines what PFAS are, why they are known as "forever chemicals," how they enter the marine food web, and the health problems they have been linked to in both wildlife and humans. We also look at the remarkable recovery of sea otters after they were nearly hunted to extinction during the fur trade and why pollution may become one of the next major challenges to their long-term survival.

Key points:

1:04 - Why should we care about sea otters?

2:16 - Near-extinction of sea otters in the early 1900s.

3:19 - Partial recovery following legal protections.

4:02 - Pollution has replaced hunting as one of the main threats.

4:26 - ‘Forever chemicals’ found in sea otters.

5:14 - Health impacts of PFAS in sea otters.

Links to more information:

Price et al., 2025. Concentrations of per- and polyfluoroalkyl substances in Canadian sea otters (Enhydra lutris) are higher near urban centers. Environmental Toxicology and Chemistry, 45(1): 80-91.

Gregr et al., 2020. Cascading social-ecological costs and benefits triggered by a recovering keystone predator. Science, 368(6496): 1243-1247.

Kannan, Perrotta and Thomas, 2006: Association between perfluorinated compounds and pathological conditions in southern sea otters. Environmental Science & Technology, 40(16):4943-4948.

Shukla et al., 2023. The diversity if animals identified as keystone species. Ecology and Evolution, 13(10):e10561.

PFAS - Environmental Working Group info

PFAS - European Commission info

PFAS - U.S. EPA info

In this episode, we explore fascinating new research showing that invasive ornamental plants don't just outcompete native vegetation—they can also change the appearance of butterflies, making them less attractive to potential mates. The discovery reveals a previously unknown way that invasive plants can affect wildlife, raising fresh concerns for butterfly conservation and the long-term health of ecosystems.

Researchers in Japan found that the caterpillars of the rare Fischer's blue butterfly (Tongeia fischeri) developed differently depending on the plant they fed on. Caterpillars raised on an invasive succulent grew into adults with altered wing coloration, particularly in ultraviolet wavelengths. Male butterflies showed a clear preference for females raised on their native host plant, suggesting that an invasive species could indirectly reduce reproductive success.

The findings highlight an important lesson in conservation biology: even when wildlife appears to adapt to environmental change, hidden biological costs may emerge that threaten populations over time.

If similar effects occur in other insects, the ecological consequences of invasive plants could be far greater than previously recognized.

The episode features Karen Hisai and professor Norio Hirai of Osaka Metropolitan University in Japan.

In This Episode:

Why invasive ornamental plants are spreading beyond gardens.

How caterpillar diet influences adult butterfly appearance.

The surprising role ultraviolet wing patterns play in butterfly courtship.

Why male butterflies preferred females raised on native plants.

What the research means for butterfly conservation.

How invasive species may affect wildlife in subtle, previously overlooked ways.

Why protecting native plants remains essential for healthy ecosystems.

Why This Research Matters

Conservation efforts often focus on preserving habitat and reducing direct threats such as pesticides or climate change. This study suggests another challenge may be hiding in plain sight.

As invasive plants spread into natural ecosystems, they may subtly alter the biology and behavior of native insects—not by killing them outright, but by changing how they communicate, recognize one another and reproduce.

Those hidden effects could ultimately determine whether vulnerable butterfly populations recover or continue to decline.

Resources and links:

Hisai et al., 2026, Effects of alien host plant on wing coloration and mating behavior of an endangered butterfly. Basic and Applied Ecology, 92:13-19.

Shackleton et al., 2022. Consensus and controversy in the discipline of invasion science. In Conservation Biology, 36(5):e13931.

Jeratthitikul et al., 2013. Phylogeography of Fischer's blue, Tongeia fischeri, in Japan: Evidence for introgressive hybridization. Molecular Phylogenetics and Evolution, 66(1):316-26.

This week, we cover six fascinating stories from the world of wildlife and conservation.

Discover how scientists are working to save Ukraine's European bison despite the ongoing war, and how environmental DNA (eDNA) is revolutionizing biodiversity research by revealing entire ecosystems from a single water sample.

We also explore surprising evidence that ancient ground squirrels scavenged mammoths, bison, and other Ice Age giants, examine the controversial roundup of wild horses in California, and discuss new research suggesting wireless radio frequency radiation may disrupt bats' navigation.

Finally, we look at growing bipartisan support for wildlife crossings across the United States, helping reconnect habitats while reducing deadly and costly collisions between animals and vehicles.

Key Points:

0:54 - The struggle to save Ukraine's bison amid the war.

3:57 - Unlocking nature's secrets through 'environmental DNA.'

6:01 -  Ancient ground squirrel poop uncovered an astonishing diet of mammoths, bison, and even large cats.

7:34 - Controversial Roundup of 450 wild horses proceeds in California.

9:08 – Wireless radiation disrupts bats' flight patterns in new study.

10:19 - Wildlife crossings gain legislative support in four U.S. states. 

Links to articles and resources:

BioGraphic, 6/2/2026, by Dustin Patar: Saving bison as bombs fall

IUCN Red List: European bison (Bison bonasus)

World Wide Fund for Nature in Ukraine: WWF-Ukraine

The Conversation, 7/7/2026, by Jenny Whilde: Fishing for DNA - how a cup of river water can reveal secrets about human health, pollution and biodiversity.

Nature, 6/9/2026, by Ewen Callaway: Ancient ground squirrels feasted on carcasses like 'zombies of the Pleistocene.'

Murchie et al., 2026. Ground squirrel coprolites preserve complex archives of ancient environmental DNA over 700,000 years.

Los Angeles Times, 6/30/2026, by Lila Seidman: 450 wild horses face a roundup in Eastern Sierra as feds proceed with contested plan.

U.S. Forest Service press release, 6/22/2026: Inyo wild horse gather starts July 8.

Environmental Health News, 6/5/2026: Study finds EMF radiation exposure disrupts bat behavior for hours.

Lindecke et al., 2026. Disruptive effects of brief radiofrequency noise exposure on migratory bat navigation.

Pew Research Center, 6/30/2026, by Carol Kaufman: States act to reduce wildlife collisions.

Scioto Analysis, 3/10/2025: Scioto Analysis releases cost-benefit analysis of wildlife crossings.

How can scientists help endangered turtles survive? In this episode, we explore how wildlife conservation professionals in Michigan are using a technique called "headstarting" to raise rare baby turtles in captivity before releasing them into the wild. You'll learn why young turtles face such steep odds from predators, habitat loss, road mortality, and the illegal pet trade, and how researchers are measuring whether this approach can rebuild wild populations. We also discuss the importance of protecting wetlands and why captive rearing is only one piece of the conservation puzzle. It's a story about endangered species recovery, hands-on science, and what it takes to give wildlife a better chance at survival. The episode features Bill Flanagan of John Ball Zoo, Will Miller of Calvin University, and Dan Earl of the Michigan Natural Features Inventory.

Key Points:

1:01 – Testing if headstarting might help spotted turtles

2:00 – Combining conservation and educating the next generation of biologists

3:17 – Spotted turtles’ reclusive habits make them difficult to study

4:44 – Dangers from the illegal pet trade

5:25 – Aging ‘ghost populations’ concern researchers

6:09 – What you can do to help turtles

Resources & Links:

IUCN Red List: Spotted Turtle

IUCN Red List: Eastern Box Turtle

International Convention on Wetlands: Global Wetland Outlook 2025

United Nations Sustainable Development Goals Report

Michigan EGLE: Status and Trends of Michigan's Wetlands: Pre-European Settlement to 2005

John Ball Zoo's Great Lakes Rare Turtles Program

Michigan Herp Atlas

Turtle Survival Alliance

Cornell Wildlife Health Lab: What the heck is herping?

Scientists long assumed tropical species would be hit hardest by climate change. But a new global study found that animals and plants in temperate regions, including North America and Europe, are already disappearing from parts of their range at alarming rates. We explore how wildlife and plants are responding to warming temperatures, why local extinctions are rising around the world, why many species aren’t moving into cooler habitats, and what the findings mean for biodiversity and conservation. The episode also features Dr. John J. Wiens, a professor at the University of Arizona, and Dr. Gopal Murali, a former postdoctoral researcher at the University of Arizona.

Key points: 

1:07 - Digging through the data to track survival of animals and plants over time.

2:34 - Nearly half of species in temperate zones have disappeared from parts of their range.

3:40 - The world has gotten hotter.

4:45 - Most temperate species are not moving north in response to climate change.

5:47 - What it means for conservation.

Useful resources:

Murali, G., Karger, D.N. & Wiens, J.J. Temperate local extinctions from climate change are outpacing tropical extinctions. Nat. Clim. Chang. (2026).

Kristen E. Saban, John J. Wiens; Unpacking the extinction crisis: rates, patterns and causes of recent extinctions in plants and animals. Proc Biol Sci. (2025)

World Meteorological Organization: 2025 State of Climate Report.

Berkeley Earth: Global Temperature Report for 2025.

New York Times, 5/26/2026, by Brad Plumer and Eric Niiler: Why scientists retired the dire climate scenario used for over a decade.

NOAA's Science on a Sphere program: Climate Model: Temperature Change (RCP 8.5) - 2006 - 2100.

European Commission: Five things you should know about climate scenarios.

Gray wolves have recovered in parts of the Great Lakes region after decades of federal protection, but research suggests they could thrive across much more of the eastern United States. Scientists identified several large areas with suitable wolf habitat, yet highways, cities, farmland and human-caused mortality make expansion difficult.

The findings also fuel ongoing debate over whether wolves should remain protected under the Endangered Species Act, raising broader questions about conservation, coexistence and how much space society is willing to share with one of North America's most iconic predators.

This episode features Jerrold Belant from Michigan State University, Merijn van den Bosch with Colorado State University and John Vucetich with Michigan Technological University.

This episode explores six biodiversity stories from around the world: how elephant dung supports diverse dung beetle communities that drive nutrient cycling and seed dispersal in African ecosystems; the death of the last known Sacramento Mountains checkerspot caterpillar, which could mean that the rare butterfly is now extinct; surprising new evidence that daddy longlegs in South America can hunt and kill frogs despite their seemingly harmless appearance;  the tagging of a nesting female sea turtle in Ecuador to better understand migration routes and reduce deadly fishing-net entanglements of eastern Pacific leatherback turtles; how an Italian farm is using forest-inspired, biodiversity-rich practices to build resilience against climate change while improving soil health; and it considers the argument that restoring and protecting nature may be one of the most effective climate solutions, simultaneously storing carbon, supporting biodiversity, and benefiting local communities.

Key points:

1:01 – Elephant poop’s essential role in African ecosystems, thanks to dunk beetles.

4:04 - The last known caterpillar of a rare butterfly has died, all but eliminating all hope of reviving the species.

5:43 - Daddy longlegs don’t just eat insects - they also hunt down frogs.

7:15 - Scientists tagged a rare sea turtle while she was laying eggs, hoping to discover her migration and feeding patterns to help with conservation decisions.

8:18 - Incorporating nature into farming practices to make crops resilient to climate change.

10:47 - Biodiversity conservation as a solution for climate change.

Articles & Resources:

Anthropocene Magazine, 5/28/2026, by Warren Cornwall: What happens to the small things when the big things disappear?

Gijsman, Nutter, and Pringle, 2026: Importance of elephants for dung beetle diversity and ecosystem functions. Science: 392(6801).

The New York Times, 5/21/2026, by Catrin Einhorn: A very lonely caterpillar, possibly the last of its kind, has died

The New York Times, 3/6/2025, by Catrin Einhorn and Harry Stevens: See how butterflies are surviving, or not, near you.

Scientific American, 5/21/2026, by Jake Buehler: Daddy longlegs are actually bloodthirsty killers - of frogs.

Calvache et al., 2026: Harvestmen (Arachnida: Opiliones) as overlooked predators of anurans in the neotropics. Ecology and Evolution: 16 (4).

Mongabay, 5/26/2026, by Bobby Bascomb: Tracking Lucero: Scientists follow a rare Eastern Pacific leatherback sea turtle.

IUCN: Leatherback turtle (Dermochelys coriacea).

Atmos, 5/25/2026, by Becca Warner: For more successful farming, follow the forest.

Biomimicry Center, Arizona State University.

The Guardian, 5/24/2026, editorial: Could nature itself hold the solution to climate change?

A recent study found dozens of previously unidentified PFAS, or “forever chemicals,” in Lake Huron’s water, fish and mussels, suggesting contamination is more widespread than previously thought. Some PFAS are linked to serious health risks, but most of the thousands of PFAS compounds in use remain poorly studied. The episode features Clarkson University environmental chemist Bernard Crimmins, who explains the advanced testing method the researchers used to find new PFAS chemicals, a fishing charter captain describing his concerns around PFAS and other contaminants in fish in the Great Lakes, and a Michigan representative who talks about a bill she introduced to limit PFAS in consumer products but which failed. Together, their insights highlight the growing challenge of understanding the health and environmental impacts of PFAS pollution across the Great Lakes region and globally.

Key points:

1:29 – A 2025 study finds dozens of previously unknown PFAS chemicals in the fish, mussels, and waters of Lake Huron.

3:55 – “Captain Steve” Hubert with Chum Bucket Charters explains his concerns about PFAS in fish and their potential impact on his business.

4:42 – Gillian Miller with Ecology Center outlines the state and federal regulatory structure.

6:06 – A 2024 Michigan bill attempts to limit PFAS in consumer products but is not passed.

 Resources:

To read this article, check out my Substack newsletter Nature Signals.

Resources:

Study: Ren et al., 2025. Suspect screening and nontargeted analysis of polyfluoroalkyl substances in Lake Huron water and biota. Journal of Great Lakes Research, 51(2):102507.

National Institute of Environmental Health Sciences: Perfluoroalkyl and polyfluoroalkyl substances (PFAS).

European Food Safety Authority: Per- and polyfluoroalkyl substances (PFAS).

U.S. Environmental Protection Agency: PFAS explained. 

Study: Yu et al., 2025. A global overview of per- and polyfluoroalkyl substance regulatory strategies and their environmental impact. Toxics, 13(4): 251.

Michigan Eat Safe Fish Guides.

Summary: This episode of Nature Signals examines recent biodiversity and environmental news, ranging from bird behavior to wolf-moose dynamics and plastic pollution. You’ll hear about how Hawaiian songbirds steal nesting materials from one another, why European city birds fear women more than men, how wolf reintroduction on Isle Royale has successfully reduced an overabundant moose population, and about the botched rescue attempt of “Timmy” the humpback whale. It concludes with research showing that toxic chemicals and climate change together harm fertility in humans and wildlife, but just one week of reduced plastic exposure can significantly lower hormone-disrupting chemicals in people.

Key points:

Biodiversity:

0:54 - Some birds steal nesting materials from other nests, adding to their threats

2:37 - City birds appear to be more afraid of women than of men, for unknown reasons

3:42 - More wolves are thriving on Isle Royale than in nearly 50 years

5:00 - The botched rescue attempt of Timmy, the humpback whale stranded in Germany

Pollution & Plastics

8:02 - Toxic chemicals and climate change work together to harm fertility across species

8:54 - Seven days without plastic contact slashes chemicals in the body

Resources:

To read this article, check out my Substack newsletter Nature Signals.

Articles & Resources:

The New York Times, 5/12/2026, by Sara Novak: Building nests is hard. That’s why some birds steal.

Wilson Ranking et al., 2026, Upcycling in the Hawaiian islands: Native forest birds commonly engage in nest material kleptoparasitism. American Naturalist.

Scientific American, 4/28/2026, by Blaire Cameron: City birds appear to be more afraid of women than men, and scientists have no idea why.

Morelli et al., 2025, Sex matters: European urban birds flee approaching women sooner than approaching men. People and Nature: 8(2): 316-326.

MLive, 4/27/2026, by Tanda Gmiter: Isle Royale’s wolf population surges to highest numbers in nearly 50 years.

Michigan Technological University, 4/27/2026, by Cyndi Perkins: Isle Royale wolf population nears historic high as moose numbers plummet.

Isle Royale Wolf-Moose Project annual reports.

Science, 5/4/2026, by Martin Enserink: Chaotic whale rescue shocks marine scientists.

The Guardian, 5/5/2026, by Kate Connolly: Rescue of Timmy the whale ‘an all-round catastrophe’ after tracker failure.

IFAW News, 5/11/2026: Timmy the whale and the limits of good intentions.

The Guardian, 5/15/2026, by Patrick Greenfield: What the fate of Timmy the whale says about conservation.

EHN, 5/1/2026, by Staff: Toxic chemicals and climate change work together to harm fertility across species.

Brander et al., 2026, Impacts of environmental stressors on fertility and fecundity across taxa, with implications for planetary health.NPJ Emerging Contaminants: 2, 12.

Medical Xpress, 4/22/2026, by Sadie Harley: Seven days without plastic contact slashes phthalates and bisphenols in body.

Harray et al., 2026, Low-plastic diet and urinary levels of plastic-associated phthalates and bisphenols: the randomized controlled PERTH trial. Nature Medicine.

Millions of butterflies are traded all over the world each year to entertain visitors in butterfly houses. But is it good for butterflies, as proponents claim? Listen to the episode to find out more about the industry, impacts on conservation and local communities, and why many experts are concerned about potential negative effects on the butterflies themselves.

Key points:

1:59 - The hidden world behind butterfly houses and the global butterfly trade

4:20 - How butterfly farms in Africa, Asia, and South America supply millions of butterflies each year

5:33 - Concerns about captive breeding, genetic mixing, disease transmission, and escaped butterflies

6:10 - What monarch butterfly studies reveal about the risks of captive rearing

7:40 – The conservation argument: Examples of butterfly farming projects supporting local communities in Kenya and Costa Rica

10:00 - How butterfly houses could become stronger tools for conservation education

10:26 - Practical ways listeners can help butterflies at home through native plants, reduced pesticide use, and habitat protectionResources:

Resources:

To read this article, check out my Substack newsletter Nature Signals.

Selected news articles and websites:

* Earth Island Journal, by Bob Koigi, 7/18/2016: How butterfly farmers are safeguarding the forest in Kenya.

* Mongabay, by Janet Njung’e, 2/8/2019: Butterfly business: Insect farmers help conserve East African forests.

* United Nations Environment Programme, 1/2/2020: Paying the school fees, one butterfly at a time.

* Kipepeo Butterfly Project, Kenya.

* Butterfly farm: El Bosque Nuevo, Costa Rica.

Conservation organizations:

* Xerces Society for Invertebrate Conservation.

* Report: State of butterflies in the United States: A Roadmap for Butterfly Conservation in the 21st Century. 2025.

* North American Butterfly Association (NABA)

* Butterfly Conservation Europe (BCE)

* MonarchWatch - researches monarch butterflies, their habitat and fall migration.

Trade organizations:

* International Butterfly Breeders Association (IBBA)

* Association for Butterflies (AFB)

Selected scientific articles:

* Parsons, 1992. The butterfly farming and trading industry in the Indo-Australian region and its role in tropical forest conservation. Tropical Lepidoptera, 3(Suppl. 1): 1-31.

* Boppré and Vane-Wright, 2012. The butterfly house industry: Conservation risks and education opportunities. Conservation & Society, 10(3): 285-303.

* Tenger-Trolander et al., 2019. Contemporary loss of migration in monarch butterflies. Proceedings of the National Academy of Sciences, 116(29): 14671-14676.

* Davis, Smith and Ballew. 2020. A poor substitute for the real thing: captive-reared monarch butterflies are weaker, paler and have less elongated wings than wild migrants. Biology Letters, the Royal Society Publishing. 16(4): 20190922.

* Wilcox et al., 2021. Captive-reared migratory monarch butterflies show natural orientation when released in the wild. Conservation physiology, 9(1): coab32.

* Saul-Gershenz, 2022. Insect zoos and butterfly houses for public education: issues related to shipping and international trade of non-native insects. Scientific and Technical Review, 41(1): 142-157.

* Tenger-Trolander, 2023. Environmental and genetic effects of captivity - are there lessons for monarch butterfly conservation? Current Opinion in Insect Science, 59: 101088.

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