The Song Within: Parasites Could Temper Cricket Noise

Parasites may be able to affect the way that crickets use mating calls to suit their best interests, according to a new study.

“Whether it’s an evolutionary adaptation, we can’t say,” said Megan Wise de Valdez, an assistant biology professor and coordinator at Texas A&M University-San Antonio and senior author of a new study published in the Journal of Parasitology. But her team’s research shows that some house crickets (Acheta domesticus) infected with horsehair worms (Paragordius varius) call less frequently in later stages of the parasites’ development.

Horsehair worms are parasites that enter the bodies of crickets and other insects at a younger stage in their lives. They grow inside their hosts until they get large enough to fill most of the body cavity of the insect.

But the horsehair worms need water to lay their eggs, so they have developed a special ability in which they convince their insect hosts to commit suicide by jumping into a water body. Once the host is inside, the worms exit their bodies, leaving the insects to drown.

Observing that the worms were able to implant this suicidal impulse into the crickets, Wise de Valdez wondered whether they could alter behavior like calling in their hosts. Crickets make noise to attract mates, but the action can also attract the unwanted attention of predators that eat the insects — an act that hardly favors horsehair worms.

The cricket chirp, produced as male insects rub their wings together, also uses up a lot of energy resources that parasites feed on.

“Calling is really energetically expensive,” Wise de Valdez said, noting that the researchers first had to identify the crickets that made the most noise in populations. In nature some male crickets hang around the chirpier insects waiting for the chance to mate with an approaching female. “You have to have a really fit individual to be a good caller.”

The researchers infected some crickets with worms and left some without and found that infected crickets called less frequently between 22 and 30 days after the parasites entered their bodies.

“We did find a significant reduction in calling but only when the nematamorph was almost ready to emerge,” she said. This makes sense because the parasites need the crickets to stay alive long enough to commit suicide by drowning.

Wise de Valdez said that though the sounds seemed to be reduced, it’s unclear whether this has developed as an evolutionary adaption on the worms’ part. The cricket could call less due to being weakened from the parasite eating its insides, for example. She said the next step to proving this behavioral change would be to get a natural predator and find out if infected crickets were eaten less often than uninfected crickets. Unlike their experiment, which used laboratory crickets, researchers would also have to use wild crickets because they may act differently than captive breeds.


Watch as a cricket infected by a horsehair worm commits suicide by drowning in a pool. Once the cricket is in the water, the worm exits the cricket’s body.

Contamination Found in Seabirds Near Georgia Superfund Site

A new study by researchers in Georgia found that contaminants from a Superfund site near Brunswick have spread much farther than previously thought.

The study, published recently in Environmental Science: Processes and Impacts, found a toxin known as Aroclor 1268 in six nesting populations of least terns (Sternula antillarum) at various locations along the Georgia coast. Aroclor 1268 is composed of polychlorinated biphenyls (PCBs), a chemical used on site at the 550-acre Linden Chemical and Plastics (LCP) facility until 1994. Since then, the plant has been closed and was designated as a Superfund site due to contamination by PCBs, mercury and other chemicals. As a Superfund site under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, the EPA began initial cleanup efforts almost 20 years ago and has the power to approve or overrule future cleanup efforts by onsite parties. The plant was the only user of the chemical in the entire southeast, co-author Gary Mills said in a University of Georgia press release.

“We wanted to look at the dispersal of Aroclor 1268… and specifically how this exposure to contaminants might be affecting the least terns nesting there,” said Gabrielle Robinson, lead author of the study, and now a shorebird biologist for the south district of Cape Cod National Seashore. Although eastern populations of the least tern are not listed under the federal Endangered Species Act, they are listed in many states, and considered rare in Georgia. “We weren’t expecting to find Aroclor 1268 in some of our sites that were farther away from LCP.”

Over the course of two breeding seasons, the team of researchers collected abandoned eggs from sites both near and far from the LCP site. Once the eggs hatched, they took fecal and feather samples from chicks to test for contaminants, as the harmful chemicals build up in fats, or pronteinaceous tissue such as feathers. They also collected depredated chick carcasses for contaminant analysis. The team tested the samples for total mercury, total PCBs, and specifically for Aroclor 1268. They found that the birds contained high enough levels of the chemical to cause lower egg production, physical and physiological abnormalities in offspring, immune system disorders, and other adverse effects.

With sites ranging across all of coastal Georgia, this is the largest study ever done of contamination from the LCP site, and shows the greatest dispersion of Aroclor 1268. The study also indicates that the chemical is spreading farther away from the site through the food chain. Least terns in particular are being contaminated by ingesting fish that have been exposed to the toxin.

This new information is not surprising, since previous studies have documented contamination in species of reptiles, marine mammals, plants, fish and invertebrates in close proximity to LCP. However, finding the chemical in birds so far removed from the contaminated site, and many years after the plant was closed is concerning, especially because seabirds are at the top of the food chain and can indicate threats to the health of the entire coastal ecosystem. Robinson says that this new information should be considered now when doing reference studies in areas previously thought to be fairly pristine. Though there is not much that can be done to clean up the contaminants once they’ve entered the food web, it is an important aspect to consider when looking at quality of habitat for birds, particularly in regards to mitigation of lost habitat.

“Exposure to contaminants, as we know, can cause health and reproductive effects that are negative,” Robinson said, “This species has a lot of conservation concerns, and contaminant exposure is just one more threat posed to these birds.”

Register Your Team for Quiz Bowl at the Annual Conference

The 18th Annual Student Quiz Bowl will take place on Tuesday, October 20 from 6:00 pm – 12:00 am during the TWS Annual Conference in Winnipeg. As a participant or as a member of the audience, you’ll have fun testing your expertise in wildlife trivia!

This event pitches teams of undergraduate students against each other to see who can rack up the most points answering questions ranging from taxonomy to wildlife management.  Last year, more than 20 teams engaged in a highly competitive contest.

The winning team gets its name emblazoned on a plaque that hangs at TWS headquarters and also receives a plaque to display at its school. Will last year’s champion, Humboldt State, defend their title or will a new champion be crowned?

Come join us and cheer for your alma mater or your favorite team!

Ready to enter your team? Please send an email to co-chairs C-Jae Breiter and Agnès Pelletier at twsqb2015@gmail.com, with the following information:

  • School name
  • Names, email addresses and cell phone numbers of 4 participants and 1 alternate (with an asterisk by the team captain’s name)

Review the official quiz bowl rules here.

Deadline for Registration: Friday, October 9 at 11:59 PM Central Time.

Judge Blocks Waters of the U.S. Rule

A federal judge in North Dakota on Thursday temporarily blocked the full implementation of the Obama Administration’s Waters of the U.S. rule. This rule, which was set to go into effect on Friday in all fifty states, expands Clean Water Act protections to smaller wetlands, streams, and tributaries to ensure a clean water supply. The EPA has stated this preliminary injunction only applies to the 13 states involved in the case, and began enacting the rule throughout the rest of the U.S. on Friday. These 13 states will still have to adhere to existing Clean Water Act protections granted to major waterways such as lakes and rivers.

Read more at The Washington Post

Obama’s Visit to Arctic Not Without Controversy

President Obama began a three day trip to Alaska on Monday to call for action against the social and environmental impacts of climate change. During this trip, President Obama will speak at the State Department’s Conference on Global Leadership, where he will call for Arctic nations to make dramatic and collective actions to combat climate change. President Obama will also become the first sitting U.S. president to visit the Alaskan Arctic by meeting with local villagers in the town of Kotzebue, whose town is currently eroding into the sea as a result of climate change. The President’s visit has been criticized by many environmental groups, who find President Obama’s remarks to be hypocritical after the Interior Department’s recent approval of a Royal Dutch Shell application to begin oil and gas drilling operations in the Chukchi Sea off of the northwest Alaskan coast.

Read more at The New York Times

Competition Seeks to Manage Invasive Pythons in Everglades

For one month next year, teams in Florida will compete to remove Burmese pythons from the Everglades. They’ll be there as part of the 2016 Python Challenge — an effort led by the Florida Fish and Wildlife Conservation Commission (FWC) and the Fish and Wildlife Foundation of Florida (Foundation) to promote citizen participation in long-term management of invasive species in the Everglades.

Public interest in citizen science and incentive programs has prompted the second Python Challenge, which was started in 2013 as a way to remove invasive Burmese pythons (Python bivittatus) from South Florida and raise awareness about invasive species in the state. The competition focuses on public outreach and training so that participants can identify, report and safely capture the large snakes. The first Python Challenge™ was a success, removing 68 Burmese pythons from the Everglades, the most ever removed in that amount of time. This year, FWC and the Foundation will look to build upon that success.

“The 2016 Python Challenge™ will take place in a larger geographic area,” said Lisa Thompson, spokesperson for FWC. The competition will be expanded through cooperation with state and federal land management agencies, such as Everglades National Park, to grant participants access to additional public lands. “Expanding the area of the competition will provide more access for participants to find and remove invasive Burmese pythons.”

There will also be increased training and educational opportunities for citizens, as participants with more experience were more effective in locating and removing snakes during the 2013 competition.

The competition will run from January 16 through February 14. Competitors can sign up individually or as part of a team of up to five people. Each participant is required to take an online training course that will educate them on how to identify, report and humanely capture pythons, including how to differentiate between invasive and native snakes. Registration is expected to begin on the PythonChallenge.org website in October and will include the option to attend in-person, hands-on training events. Rules, prizes and events are still being developed but will also be posted on the website when they are finalized. In 2013, prizes were awarded for the longest python removed and the most pythons removed.

Burmese pythons continue to plague the Everglades region, but there are currently no reliable population estimates due to an exceedingly low rate of detection. For this reason, goals of the challenge are to raise public awareness and expand public participation by offering opportunities to actively participate in managing invasive wildlife, rather than determine the effects of the competition on python populations. However, data from the large sample size removed in 2013 were used by partners to better understand seasonal behaviors of the snakes.

Citizens are encouraged to participate in managing Florida’s invasive species in a variety of other ways as well. The Python Removal Program is a citizen science program in which trained and permitted individuals can remove snakes and other invasive reptiles from state lands, but is not a hunting or recreational program. Several state lands also allow hunters to remove Burmese pythons during open hunting seasons and some offer Conditional Reptiles Seasons. Burmese pythons and other invasive species can also be removed from private lands year round. The public is advised to report sightings of nonnative species in Florida to FWC’s Exotic Species Hotline 888-IVE-GOT1 (888-483-4681), and spread the message of responsible pet ownership.

As leaders in wildlife science, management and conservation, The Wildlife Society offers its position on a number of important wildlife issues across North America. Read The Wildlife Society’s position on invasive species here.

Resolving Human-Wildlife Conflicts

The Clash between Responsible Management and Perceptions

Many people consider the annual migration of the sandhill crane an unrivaled spectacle of nature. Each year, more than 80 percent of the North American crane population converges on the Platte River in Nebraska. Their stopover in Kearny — the site of Audubon’s Nebraska Crane Festival — has earned the small town the title “Sandhill Crane Capital of the World.” Every year, the arrival of more than half a million birds in March draws thousands of visitors from around the world who are eager to witness this natural phenomenon.

Although the cacophonous crane calls are cause for celebration in Kearny, the birds haven’t always been so popular elsewhere along their southern migration route. In New Mexico’s Rio Grande Valley — where nearly 30,000 sandhill cranes (Grus canadensis) and 50,000 snow geese (Chen caerulescens) spend the winter — farmers used to dread their arrival. Overwintering birds foraged on alfalfa, chili pepper and wheat, often devastating crops. The combination of the two — an iconic bird species and extensive agricultural damage — exemplifies the classic elements that create a human-wildlife conflict.

A look at how wildlife professionals conduct their work when two sides of a conflict seem to be at loggerheads provides insights into how our profession applies integrated management and lethal control within the context of the North American Model of Wildlife Conservation.

The Model 

The North American Model of Wildlife Conservation is built upon the premise that wildlife is a public trust resource — owned by no one and managed by the government for the benefit of present and future generations. Although not formally written until 2001, the model has its origins in the 19th century conservation movement and represents the culmination of continually evolving laws and regulations that had been put in place to prevent the over-exploitation of wildlife resources and ways to fund wildlife management.

In addition to the concept of wildlife as a public trust, The Model is built on six other tenets: 1.) elimination of commercial markets for game; 2.) allocation of wildlife by law rather than privilege; 3.) wildlife should be killed only for legitimate purposes; 4.) wildlife is an international resource; 5.) science is the basis for wildlife policy; and 6.) hunting is democratic. These tenets have been widely accepted by wildlife professionals, incorporated into the workings of state wildlife agencies, and endorsed by professional organizations such as The Wildlife Society.

Underlying all six tenets is the idea that lethal take — the killing of wildlife — can be prevented, allowed or even encouraged, provided appropriate regulatory processes are followed that are in line with specific management goals and objectives. Furthermore, local, state and federal agencies work together within that regulatory framework to preserve North American wildlife.

The Evolution of Wildlife Services

Some of the earliest actions taken by the U.S. government to manage wildlife were efforts to prevent and control damage to agricultural crops. In the wake of the first National Biological Survey, Congress authorized the U.S. Department of Agriculture in 1885 to help farmers manage crop damage caused by birds.

Responsibilities of the program soon expanded to include predator control to protect livestock as well as rabies control. Other early priorities centered on agricultural economics and research on methods and tools to help manage wildlife damage issues.

The program remained in the USDA until 1939 when it was transferred to the U.S. Department of the Interior. Then in 1985, it was moved back to the USDA. Over the years, although the program changed names numerous times, its most recognized name was Animal Damage Control. Then in1996, it became Wildlife Services, the name currently in use today. The evolution of Wildlife Services took place within the framework and foundation of the North American Model and focused on protecting the needs of people while recognizing the high value society places on wildlife.

Conflict Resolution in Practice

Resolution of wildlife conflicts relies upon a structured decision model known as integrated wildlife damage management (IWDM). Wildlife Services as well as state and federal agencies and independent professionals resolve wildlife damage issues by applying this model. Not only does employing IWDM help ensure success, but it also helps maintain the profession’s fidelity to the North American Model.

A Wildlife Services technician and partner get ready to release a Kirtland’s warbler after banding it. The project in Wisconsin is a collaborative effort of federal and state agencies and private industry, with strong volunteer support. Image Credit: USFWS, Joel Trick

A Wildlife Services technician and partner get ready to release a Kirtland’s warbler after banding it. The project in Wisconsin is a collaborative effort of federal and state agencies and private industry, with strong volunteer support. Image Credit: USFWS, Joel Trick

In most cases, an individual or group reports a wildlife damage conflict that initiates the IWDM process. Wildlife damage management professionals typically start with an assessment that involves identifying the species causing the damage, the affected resources, and the severity of the damage. Solutions can range from technical assistance in which professionals give requestors information on how to resolve the conflict themselves to direct management in which professional IWDM practitioners apply techniques to disperse or remove problem-causing animals.

Management strategies frequently involve sequential application of increasingly aggressive techniques to solve the problem while minimizing the effort, cost and impact to the wildlife species. To ensure successful resolutions of conflicts, IWDM also requires monitoring the application and results.

For example, a homeowner may be concerned about beavers damming a stream. Simply educating the homeowner about beaver ecology and the benefits associated with beaver ponds may put his mind at ease. However, if a homeowner is worried that a beaver might destroy an expensive ornamental tree, the wildlife specialist may recommend installing anti-chewing structures around the tree’s base. Or if a homeowner is tolerant of some flooding but worried that his septic system may be damaged from high water levels, the specialist may suggest the homeowner install a pond-leveling device.

In other situations, more aggressive measures may be needed. For example, a farmer may not tolerate any flooding of a corn field from beaver activity in a nearby stream and request the dam be removed. This strategy may work if the offending animal is a dispersing two-year-old beaver that can be dissuaded from the area by simply removing the dam, but an established colony may continue to rebuild causing further problems. In this case, lethal removal by trapping may be necessary.

When the Stakes Are High

Critics of lethal control frequently argue that public funds should not be used to protect private resources from wildlife damage. But history has shown that in the absence of professional IWDM services, some agricultural producers or resource owners will go to great extents to protect their investments — often with tragic consequences. Indiscriminant use of poisons and lethal bait has killed thousands of non-target animals; however, IWDM programs have proven to be effective at quickly and efficiently removing depredating animals with minimal risk to non-target species. Because the North American Model establishes wildlife as a public resource, government has a legitimate role in resolving wildlife conflicts when they impact private enterprises or human health and safety.

Image Credit: USDA Wildlife Services

Image Credit: USDA Wildlife Services

In the case of the Rio Grande Valley sandhill cranes, collaboration between state and federal agencies resulted in a strategy that involves habitat management, harassment and lethal take through regulated public hunting. Portions of nearby wildlife refuges and other management areas are planted with lure crops such as corn to draw birds away from agricultural crops on private lands. To further discourage birds from feeding on commercial crops, a USDA Wildlife Services technician coordinates with the refuge systems and uses pyrotechnics to harass and move birds from farmers’ fields to lure crops at alternate forage sites.

Another part of the strategy to reduce crop damage involves killing offending birds. As hunting season approaches, licensed hunters are encouraged to contact Wildlife Services for information on bird densities and crop damage locations. This coordination allows hunters to remove birds from areas where they are causing damage, while simultaneously reinforcing the non-lethal pyrotechnic methods by preventing cranes and geese from becoming habituated to them.

Wildlife technicians remove cowbirds from a modified Australian crow trap as part of recovery efforts for the endangered Kirtland’s warbler. An average of 200 cowbirds were removed in Wisconsin during each nesting season from 2008-2014, enabling the first successful nesting outside of Michigan in decades. The male Kirtland’s warbler has a distinctive bright yellow breast and song. Image Credit: USFWS, Joel Trick

Wildlife technicians remove cowbirds from a modified Australian crow trap as part of recovery efforts for the endangered Kirtland’s warbler. An average of 200 cowbirds were removed in Wisconsin during each nesting season from 2008-2014, enabling the first successful nesting outside of Michigan in decades. The male Kirtland’s warbler has a distinctive bright yellow breast and song. Image Credit: USFWS, Joel Trick

This integrated management strategy — in place for nearly 20 years now — has dramatically reduced crop damage and enhanced landowner and producer tolerance, while simultaneously enhancing the conservation of these valued wildlife resources throughout their range and in New Mexico’s Rio Grande Valley.

Opposition to Lethal Control

The sandhill crane mitigation effort is just one of many examples of how effective wildlife damage management must take into consideration the many competing values of a diverse public served by the federal and state wildlife agencies entrusted with managing wildlife resources. In some cases, agencies use regulated sport hunting — a form of lethal control — to meet management goals. But in other cases, sport hunting may not be a viable alternative.

Wildlife management agencies sometimes have their own staff conduct lethal measures to protect agriculture, human health and safety, and even other wildlife. These activities fall into three categories: population reduction, such as reducing deer herds to restore forest regeneration; removal of problem individuals, such as eliminating fox preying on nesting piping plover; and reinforcement of hazing to prevent habituation, such as removing birds from airport runways.

Using lethal techniques often draws criticism, with opponents offering a long list of alternatives including birth control, habitat manipulation, exclusion and tolerance. In truth, all are important tools in an IWDM approach. However, the loss of lethal management as a technique available to wildlife agencies would not only jeopardize resolution of wildlife conflicts, but also the survival of some species.

Take, for example, the story of the Kirtland’s warbler (Setophaga kirtlandii), a bird that was nearly extinct 50 years ago. Its long road to recovery and some of the choices made to secure its recovery also illustrate the necessity of lethal control methods.

This endangered warbler requires dense young stands of fire-dependent Jack pine (Pinus banksiana) for nesting. However, fire suppression had severely restricted available nesting habitat leaving only isolated patches in the Lower Peninsula of Michigan. Extensive habitat management conducted by a broad partnership of federal, state and private groups improved habitat conditions in Michigan as well as in Wisconsin and Canada. However, the birds failed to recolonize these habitats because their nests were being parasitized by brown-headed cowbirds (Molothrus ater). At the request of the U.S. Fish and Wildlife Service and Wisconsin Department of Natural Resources, Wildlife Services initiated a cowbird trapping program in Wisconsin in 2008. That spring, the endangered Kirtland’s warbler successfully nested outside of Michigan for the first time in more than 40 years. Last year, seven breeding pairs in Wisconsin successfully fledged eight to 10 young — an unlikely accomplishment without the continued lethal removal of brown-headed cowbirds. A similar trapping program began in 1972 in Michigan and by 2002 Kirtland warbler fledging rates had increased from less than one to nearly three birds per nest.

Finding Acceptable Resolutions

Although the wildlife profession has long recognized the legitimacy of lethal control when practiced ethically within a science-based management strategy, the practice continues to draw strong public opposition and, in some instances, disagreements within the wildlife profession.

Some stakeholders view the killing of any animals as unnecessary and harmful not only to wildlife but to society. The changing demographics of U.S. citizens and their increasing dissociation from the natural world has created a knowledge gap in which misinformation can be used to generate widespread opposition from far beyond the areas affected by a conflict.

Exacerbating these situations is the modern social media movement, which facilitates instantaneous dissemination of unvetted information and opinions designed to sway public opinion. As a result, wildlife managers often find themselves balancing the needs of directly impacted stakeholders with those of far-removed wildlife enthusiasts.

Guidelines theme artProfessional organizations such as The Wildlife Society have long supported lethal take. TWS’s Standing Position Statement on the North American Model of Wildlife Conservation states, “Prevention or control of wildlife damage, which often includes removal of the animals responsible for the damage, is an essential and responsible part of wildlife management.”

This is not to say that the wildlife community itself is unified in its acceptance of lethal control. A healthy debate is ongoing, which will be examined in-depth in the symposium, “Wildlife Conservation’s Dilemma: Fur, Feather, Fins, Steel and People,” at The Wildlife Society’s 22nd Annual Conference to be held in October in Winnipeg. Several TWS Working Groups will participate in the discussion including: Hunting, Trapping and Conservation; Human Dimensions; Wildlife Damage Management; and Public Conservation, Education and Extension.

Wildlife Services staff will participate in the symposium. Our hope is that this gathering will lead to a renewed commitment to improve communications within and outside the wildlife profession regarding the importance of lethal take as a tool to manage wildlife conflict issues within the context of the North American Model of Wildlife Conservation.

Fish and Wildlife Service Expands Hunting and Fishing on Refuges

The U.S. Fish and Wildlife Service (FWS) is expanding hunting and fishing opportunities across the National Wildlife Refuge System. The new rules directly impact 21 refuges, with sport fishing being introduced to four refuges and hunting being introduced to one. This brings the total amount of wildlife refuges that allow hunting to 336 and the total that allow fishing to 275.

The National Wildlife Refuge System consists of 562 refuges and administers them for the conservation, management, and restoration of the fish, wildlife, and plant resources and their habitats within the United States. Refuges provide opportunities for many wildlife-dependent recreational activities, with six primary activities of environmental education, interpretation, photography, wildlife observation, hunting, and fishing.

New hunting opportunities for migratory birds will be available for youth at the Tualatin River National Wildlife Refuge in Oregon. Sport fishing will be offered at Ardhoch, Lake Alice, Rose Lake, and Silver Lake National Wildlife Refuges in North Dakota. An additional 16 refuges across 14 states will expand their hunting and fishing opportunities, allowing new types of activities on top of what was previously available. One such refuge, Merritt Island National Wildlife Refuge in Florida, will allow big game hunting in addition to the already available migratory bird hunting and sport fishing.

Dan Ashe, director of FWS, said in the announcement that “By expanding those opportunities, we are enhancing the lives of millions of Americans, stimulating the national economy to which hunting and fishing contribute significantly, and generating much needed additional funding for wildlife conservation.”

According to FWS, the National Wildlife Refuge System added $2.4 billion to the economy and provided more than 35,000 jobs in 2013. More than 47 million people visit refuges every year, including those that hunt and fish. Hunting and fishing contribute funds to wildlife conservation through the Pittman-Robertson Act and the Dingell-Johnson Act. These acts place excise taxes on hunting and fishing equipment which go to habitat restoration programs, research, and management activities. The programs have distributed more than $15 billion for wildlife and fish conservation since being enacted.

The Wildlife Society supports regulated hunting as an appropriate means of managing wildlife populations and encourages opportunities for hunting when based on scientific information, as consistent with the North American Model of Wildlife Conservation.

How Frogs Cope With Road Salt and Brackish Water

Some frogs may be able to adapt to brackish, salty water, according to new research.

“Coastal frogs are less likely to avoid placing their eggs in salt water,” said Molly Albecker about a population of American green tree frogs, Hyla cinerea, while presenting her research at the Ecological Society of America’s annual conference in Baltimore. Albecker is a biology researcher at the East Carolina University in Greenville, N.C. working on the ongoing study.

In order to see whether this ability to tolerate more brackish water was a characteristic of the tree frog species in general, Albecker participated in studies that examined the kinds of water that inland and coastal populations of green tree frogs and a related species, Cope’s gray tree frog (Hyla chrysoscelis), preferred.

In the wild, male green tree frogs usually mount the females, who then will piggyback it around sampling pools that can resemble the water-filled pails. The females use a pelvic patch that may allow them to detect salinity, among other things.

They gave pregnant females different choices in which to lay their eggs by laying out plastic pails that resemble sampling pools. The researchers filled some pails with salt water and others with fresh water to determine what the frogs would favor.

Albercker said that they found females of both green tree frog populations as well as the other species prefer to lay their eggs in fresh water. But inland female green tree frogs were pickier about laying their eggs in salt water than their coastal cousins.

She said they aren’t clear exactly why the coastal frogs have adapted a higher ability to deal with salt water, but it could have to do with more mucus glands that provide them a defense.

They then watched these different scenarios to see how many tadpoles hatched in each of them, and found that coastal eggs had higher hatching rates than inland frog eggs.

Albecker said that studies like this can determine how biodiversity along the coast of North Carolina may be affected as the area becomes more brackish with sea water rises.

Road Salt Hopping

But rising sea levels aren’t the only way that salt is entering amphibian ecosystems. A study published recently in Environmental Toxicology and Chemistry found that wood frog (Rana sylvatica) tadpoles in Ohio may grow more when exposed to road salt, leading to larger adults.

But there’s a catch — juvenile wood frogs have a lower survival rate.

Wood frog tadpoles grew larger in ponds contaminated with road salt. The salt appeared to restrict the zooplankton population, which competes for the algae that tadpoles feed on. Image Credit: Michael F. Benard

Wood frog tadpoles grew larger in ponds contaminated with road salt. The salt appeared to restrict the zooplankton population, which competes for the algae that tadpoles feed on. Image Credit: Michael F. Benard

“This study really shows that you need to look across multiple life stages to get a good look at what environmental pollutants are doing,” said Kacey Dananay, a PhD student at Case Western Reserve University and lead author of the study.

One of the reasons for this could be that the salt seemed to give zooplankton a hard time growing. Since zooplankton feed on some of the same algae as wood frogs, the salt may have resulted in the frogs having more to eat.

But the researchers aren’t exactly sure why the juveniles don’t survive as much.

“We would predict the frogs that are larger at metamorphosis would do better — larger body mass is usually an indication that they are more fit,” Dananay said. “Maybe they’re more susceptible to disease or there’s a physiological change we can’t see.”

Further studies are planned on the physiological effects salt has on wood frogs.

Hawaiian Monk Seals Gain Critical Habitat Protection

Critically endangered Hawaiian monk seals (Monachus schauinslandi) now have a better chance to revive their population thanks to an increase in almost 7,000 square miles of designated critical habitat.

The U.S. National Marine Fisheries Service (NMFS) finalized its ruling to expand habitat this month, seven years after environmental organizations and advocacy groups such as the Hawaiian Environmental Alliance filed a legal petition to protect the seals that are native to Hawaii and are declining in population.

“Hawaii has a responsibility to protect our natural and cultural heritage,” said Suzanne Case, chairperson for the Hawaii Department of Land and Natural Resources, in a press release. “A part of that is making sure that our very special, unique, native Hawaiian monk seals have safe places to thrive.”

As part of the effort, NMFS will focus on protecting areas most important for the seals’ foraging, pupping and resting. Monk seals are currently protected under state and federal law with only 1,100 of them left in the world. In the last decade, their numbers have declined about 4 percent per year.

Under the Endangered Species Act, when an area is designated as critical habitat, federally permitted or funded projects may need to be altered to avoid damaging habitat. By enforcing critical habitats, the DLNR can better manage coastal resources.

“We look forward to enhanced state and federal co-management of monk seals throughout Hawaii,” Case said. “Critical habitat helps manage federal activities to avoid habitat destruction. Most fisherman and other ocean users will never even notice this rule has been implemented.” This is because the new habitat rule won’t impact most recreational activities including swimming, boating, fish and gathering, she said.

Case hopes this will helps the DLNR work together with the federal government to ensure protection of the seal and other wildlife in the future. “We see this rule as an opportunity to improve our partnership with federal natural resources management and it complements the work the state is doing to conserve monk seals.”