Playing with Nature

"Parthenium Hysterophorus" by Biswarup Ganguly is licensed under CC 3.0

“Parthenium Hysterophorus” by Biswarup Ganguly is licensed under CC 3.0

Humans have spent most of our time on Earth bending and twisting nature to fit our needs and wants. About 12000 year ago, we figured out that if we purposefully grow a few plants in large amounts, then we could survive the seasons in one place. We also learned that if we hold on to a few of the more docile animals, then we could form our own herds of food that go where we go, or better yet, stay where we stay. We evolved from our hunter-gatherer ancestors into a people that can cultivate our own sustenance, and we never looked back. Our new skill made us quite adept at sustaining plant and animal species in places where they didn’t quite belong, but we haven’t done very well at addressing the consequences of the spread of invasive species – organisms that do much more harm than good in new environments.

Invasive species are brought into new areas in a number of ways. Some animal species, such as the Burmese python of Florida or the lionfish of the Caribbean, are imported as pets and released into the wild when their owners tire of them (US Department of Agriculture). Plants such as the Chinese tallow, an ornamental plant introduced to the US in the 1700s, still outcompetes some native plants in the south today (USDA). Other species such as the red imported fire ant (introduced to the US via a cargo ship), are brought into new areas by accident (USDA).

For a while, our solution to this problem was to fight nature with nature. With our vast knowledge of the way world works, we paired our pests with likely predators from all over the world. The cane toads introduced to Australia to protect sugarcane saved the crops, depleted the food of Australian native species, and killed anything that made the mistake of eating it. The weevils introduced to North America to control the bothersome Musk and Canadian thistle didn’t just eat thistle. The list goes on. Obviously there were some details we missed when we attempted to pit nature against itself.

It’s time that we start looking at the way that these species spread. Sometimes these organisms do not occur in areas that they statistically appear. It makes us wonder what it is about one habitat that can sustain an invasive species that is so different from another similar habitat, or what is it about the invasive population that is so different from the original population. Wayne Dawson of the University of Konstanz said that “novel plants in novel environments means novel interactions, which sets the stage for evolution to continue in a way that would be different if species remained geographically separated on their own continents of origin.” This can be true of any species Narrowing down where exactly a species may spread next may help us understand what makes their invasion of new habitats so successful.

Kumar P. Mainali and a team of scientists from the University of Maryland took the first step to do just that. Using the weed, Parthenium hysterophorus, as a model species, Mainali and his team compared four statistical models for species distribution to each other in order to determine which would be the best to predict the spread an invasive species, and to improve upon each statistical model. P. hysterophorus is a weed with a great global presence. It has spread from its origins in the tropics of the Americas to Africa, Australia, and Asia. Perhaps with the improvements of these models we won’t be blindsided by the results we desired to see. Instead, we will be given a well-rounded idea of the species we have transferred from one place to another. The information provided by these improved models should also allow us to develop a management plan as we track its potential spread. The use of these models could be a fantastic way to determine whether or not humans are truly ready to play with nature.


Works Cited

Mainali, K. P., Warren, D. L., Dhileepan, K., McConnachie, A., Strathie, L., Hassan, G., Karki, D., Shrestha, B. B. and Parmesan, C. (2015), Projecting future expansion of invasive species: Comparing and improving methodologies for species distribution modeling. Glob Change Biol. Accepted Author Manuscript. doi:10.1111/gcb.13038


Wayne Dawson, quote from Sweet smelling water hyacinth is trouble by Klaus Esterluss. DW.                        


United States Department of Agriculture. National Invasive Species Information Center (NISIC): Gateway to invasive species information; covering Federal, State, local, and international sources.



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Juvenile Turtles More Destructive than Media Portrayals Suggest

Turtles in a row

Turtles in a row” by Tambako the Jaguar is licensed under CC BY-ND 2.0

Let us imagine a young child who has grown bored of his pet turtles. The parents decide that the right thing to do is to release the turtles into the wild. In the child’s mind, the turtles go on to become crime fighting ninjas like in the popular cartoon series “Teenage Mutant Ninja Turtles”. The child is correct in the sense that his red-eared sliders will thrive, but research shows the sinister reality of these stars: their success threatens other turtle species across the United States.

Red-eared sliders have become a popular pet, but their popularity has a dark side. Their native range is in the Southern United States, but they have since spread to distant corners of the country. According to the United States Geological Survey’s website, they have spread as far as Oregon, New York, and even Hawaii. In fact, the IUCN’s Invasive Species Specialist Group has listed them among the top one hundred most invasive species. So what kind of damage are these turtles causing to their new habitats?

A new study published in Biological Conservation by Dr. Steven Pearson and others at Drexel University sheds some light on the issue. Their research found that the invasive red-eared slider (Trachemys scripta elegans) outcompeted the red-bellied turtle (Pseudemys rubriventris) in a series of experiments.

The results showed that red-eared sliders could outcompete the red bellied turtles through a food based mechanism. Under some conditions, they could simply consume more of the food and thus limit the resources of the red-bellied turtles. When food was abundant, the red-bellied turtles actually ate more food. This suggests that even when red-eared sliders receive less resources, they have higher efficiency and can still outcompete the red-bellied turtles.

In any environment where the red-eared slider can survive, it can outcompete and thrive. Indeed, we are already seeing these effects across the United States as the red-eared slider expands its territory. The problem is not just restricted to the United States either. The slider’s worldwide popularity as a pet contributes to its invasiveness and now the slider threatens to outcompete turtles around the world.

For example, experts became alarmed when there were reported sightings of red-eared sliders in Australia. Professor Burgin from the University of Western Sydney stated that “once they get a toe-hold in the wild, they become established quite quickly. Feral turtles … present a real threat to the indigenous turtle population because of their aggressiveness and their ability to cope with more extreme conditions”. Their fear seems rightfully placed considering the world’s ongoing biodiversity crisis. The invasion of red-eared sliders may make our current ecological problems worse.

So what can be done about this threat? Regulations have already been put in place to prevent the sale of red-eared sliders smaller than 4 inches in the United States. Although the ban was put in place to prevent the spread of salmonella, there are likely to be ecological benefits as well. By forcing consumers to only be able to consider older turtles as pets, the regulations should prevent people from underestimating the amount of care a pet turtle requires and thus result in less abandonments. Less abandoned turtles will mean less invasiveness.

That being said, there are those in the turtle breeding industry who have been working to minimize salmonella in their baby turtles. In a news piece with NPR, industry scientist Mark Mitchel claims to have been able to reduce their salmonella rates from 30% to a mere 1%. Given their great results, the industry seeks to repeal the ban. To be sure, they make a good point if we only consider the ban as a public health issue. However, we should keep in mind the positive ecological impacts of the regulations before considering repealing it.

Regulations cannot replace responsibility. Despite all of its troublemaking invasiveness, the red-eared slider is simply too charismatic. It will be a popular pet for years to come regardless of regulations. We must make a commitment to care for our red-eared sliders and in doing so, care for our wildlife as well. With our help, all turtles can thrive.

Works Cited

“Global Invasive Species Database.” Global Invasive Species Database. Invasive Species Specialist Group, n.d. Web. 23 Oct. 2015.

“News Archives.” Western Sydney University. University of Western Sydney, n.d. Web. 23 Oct. 2015. <;.

Pearson, Steven H., Harold W. Avery, and James R. Spotila. “Juvenile Invasive Red-eared Slider Turtles Negatively Impact the Growth of Native Turtles: Implications for Global Freshwater Turtle Populations.” Biological Conservation 186 (2015): 115-21. Web.

“Red-eared Slider – FactSheet.” Red-eared Slider – FactSheet. United States Geological Survey, n.d. Web. 23 Oct. 2015.

Rovner, Julie. “Bill Seeks to Lift Ban on Baby Pet Turtles.” NPR. NPR, n.d. Web. 23 Oct. 2015.

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Survey Shows that Bats Prefer Coffee over Tea

“White-winged vampire bat (Diaemus youngi)” Photograph by Gcarter2 at en.wikipedia, distributed under CC-BY-SA-2.5 license.

Christopher Nolan’s Dark Knight patrols an inhospitable city and faces a daily struggle of survival just like the bats of the Western Ghats of India. These bats are also fighting for their lives against their loss of habitat to tea and other crop plantations. The Western Ghats is the most densely populated of the 35 biodiversity hotspots in the world. It’s little surprise that just six percent of the land has vegetation untouched by humans. The native forest now exists as fragments, which has devastated animal populations, bats included. The presence of humans in the area cannot be denied or easily reversed, so strategies to continue the human use of the land while improving the habitat for animals is essential to our coexistence.

Luckily, Claire Wordley and her colleagues at the University of Leeds in the United Kingdom recently published a journal article in Biological Conservation about bat habitat fragmentation. They researched how a variety of species of bats handle changes in land use. The team looked at populations of bats in areas of different land composition to determine which factors contribute to better habitats.

It turns out that tea plantations that heavily modified the land were not very hospitable to bats, however, land that is dominated with tea crop that also contains forest fragments could house several species of bats. Coffee grown in the shade of the existing forest also provided good habitat. Basically, the more scattered forest an area has, the more likely that area can support bat populations. This makes sense since the bats’ native habitat is forest. It’s just a good thing they can still survive with the tea and coffee crop dominating their home.

The researchers found that the individual bat species’ niches were generally broad, which is very helpful when the habitat is narrow. Small scale (100-500m) variability in habitat can still effect the populations, probably because bats can exploit small or even isolated foraging areas. This opens up a lot of viable land use strategies to conserve bats. The most obvious method consists of avoiding covering entire landscapes with tea crop. Perhaps coffee could be a bigger focus instead of tea. Leaving some forest corridors between their habitats would also be helpful.

Some people, for the sake of their economic interests, may disagree with altering our commercial crop systems. However, the bats and other animals and plants in the forest fragments are an essential part of the local ecosystems. Forests animals can provide human and ecosystem benefits like pollination and pest control, which offset the economic costs of conservation.

Habitat fragmentation is a serious issue in the Western Ghats and everywhere else. “Nearly 20 percent of the world’s remaining forest is the distance of a football field — or about 100 meters — away from a forest edge. Seventy percent of forest lands are within a half-mile of a forest edge. That means almost no forest can really be considered wilderness,” said Dr. Nick Haddad, William Neal Reynolds Distinguished Professor of Biological Sciences at North Carolina State, in a recent NC State News press release.

While the statistic is sad, human activity is inevitable, and with the exponential human population growth trend, our natural resource exploitation is fated to worsen. The best strategies will come from our creativity to use resources so that land is still suitable for other animals as well. A clear example is given by how we can fragment our own tea plantations and plant more coffee to allow bats to inhabit the scatter of forest that’s left. It’s not only the changes that they deserve, but also the ones that they need right now.



Wordley, C., Sankaran, M., Mudappa, D., & Altringham, J. (n.d.). Landscape scale habitat suitability modelling of bats in the Western Ghats of India: Bats like something in their tea. Biological Conservation, 529-536.

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A Lack of Foresight: One of Conversation Biology’s Most Detrimental Shortcomings

Protecting endangered species is a tough job, and Gary Langham, the Chief Scientist of the National Audubon Society, believes that future climate change will it even tougher. In Science Friday’s Can Conservation Efforts Save the Birds? podcast, Langham said that “climate change is going to come in and making everything more complicated…[climate change] threatens to come in and cut across all species and all threats to make what was already a hard job even harder.” It has become increasingly apparent that climate change, primarily caused by human activity, profoundly affects the environment. For some species, their current environments will become uninhabitable due to climate change, and this will inevitably put certain species at risk for extinction.

If we know that species will be threatened by human induced climate change in the future, are conservation biologists preparing now? Langham wanted to answer this question, so his team at the National Audubon Society in Washington D.C. along with researchers from the National Audubon Society in San Francisco decided to use climate change to predict how populations of 588 North American bird species will change in the near future. The researchers also compared their predictions to current conservation efforts. The results of their study were shocking, and made on thing certain: conservation biologists are not preparing for what lies ahead.

Langham found that, given the most dramatic level of possible climate change, 314 of the species studied are predicted to lose over half of their geographic range, and 126 of these species will lose habitat without gaining any. To elucidate how each species will be affected by climate change, the researchers categorized the species by climate threat level. Of the 588 species, the researchers classified 126 species as climate endangered, 188 species as climate threatened, and only 274 as climate stable.

The researchers also claimed that these startling numbers are not reflected in current conservation efforts. According to the researchers, “relatively few bird species in our climate endangered or climate threatened categories are of current conservation priority.” For example, the Baird’s Sparrow (pictured below) is expected to lose more than 95% of its geographic range in the near future. However, the IUCN Red List, which monitors threatened species, considers it to be of “Least Concern”. According to the IUCN Red List’s website the “Least Concern” category “is used to highlight species that have a relatively low extinction risk.” The loss of 95% of its habitat poses an undeniable risk to any species’ continued survival. This lack of foresight is unnerving and suggests that legislators and biologists merely focus on bird species that are currently in danger rather than species that will become endangered. In order to protect species to the best of their ability, conservation biologists must account for both present and future threats to survival.

According to this study, the Baird's Sparrow, a species endemic to North America, is expected to lose 95% of its geographic range. However, the Baird's Sparrow is considered to be of "Least Concern" by the IUCN Red List, which tracks the conservation status of species.  "Baird's Sparrow" by Tom Benson is licensed under CC 2.0

According to this study, the Baird’s Sparrow, a species endemic to North America, is expected to lose 95% of its geographic range. However, the Baird’s Sparrow is considered to be of “Least Concern” by the IUCN Red List, which tracks the conservation status of species.
Baird’s Sparrow” by Tom Benson is licensed under CC 2.0

Additionally, the researchers found that location, time of year and emission levels heavily influence where birds reside. With this information, we can better orchestrate conservation efforts. Predicting these patterns can help conservation biologists and legislators wisely invest time, money and other limited resources. For example, hunting in a given area could be regulated based on time of year and species volume.

Skeptics may doubt these predictions and question the models used. However, North American bird population distributions through space and time are some of the best recorded of all species. The statistical models and predictions from the study were based on information from the North American Breeding Bird Survey (BBS) and Audubon Christmas Bird Count (CBC). According to the researchers, the BBS and CBC are “two of the most comprehensive continental datasets of vertebrates in the world.” Given this, we can trust the legitimacy of these predictions.

The results of this study hold heavy implications for the field of conservation biology. We aren’t thinking ahead. Right now, humans are making messes and conservation biologists are scrambling to clean them up. We need to invest more energy in predicting and preparing rather than responding. If conservation biologists can see the path down which nature is walking, they can know where and when to step in.


Ammodramus bairdii (Baird’s Sparrow). (n.d.). Retrieved October 23, 2015, from

IUCN Red List Frequently Asked Questions. (n.d.). Retrieved October 23, 2015, from

Langham, G. M., Schuetz, J. G., Distler, T., Soykan, C. U., & Wilsey, C. (2015).       Conservation Status of North American Birds in the Face of Future Climate Change. Plos ONE, 10(9), 1-16. doi:10.1371/journal.pone.0135350

Link to original article

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The “Caped Crusader” in All of Us: Using Citizen Science to Understand Bat Populations

Featured image

Hoary Bat (Lasiurus cinerus), male” by J. N. Stuart is licenses under CC 2.0

Everyone knows DC Comic’s infamous “Caped Crusader” Batman as one of America’s most beloved superheroes. Although he does not possess any supernatural powers like many other comparable vigilantes, he uses what privileges and resources he has to save Gotham from the threats of evil. Batman’s efforts to protect the city he loves is comparable to the work local volunteers can make to preserve the wildlife in their region, one of the least thought over animals being bats. The preservation of bats could be furthered with the adoption of using volunteers to aid modern research projects.

Public participation in understanding bat species within places like Texas should be a matter of great importance. Texas houses about 10 major bat colonies with one, the Bracken Cave, breeding the largest colony of bats in the world. With such large bat populations, ecologist will need a lot of help collecting data for the millions of bats who reside in bat dense locations like the Texas caves. Citizen scientific research could be extremely beneficial to ecological research for the community. Benefits include increased community awareness on bat ecosystems, more detailed data for researchers, and more effective initiatives to manage the development of the bat population by law makers.

In a new study in the Journal of Biological Conservation, Dr. Stuart Newson of the British Trust for Ornithology used large scale volunteer-based bat recordings to better understand species distribution and abundance of different bat species. The study, that took place in Norfolk, England, used the Norfolk Bat Survey to allow everyday citizens to access passive real-time bat detectors. The residents could place the bat detectors in any place of their choice within Norfolk. These devices recorded the signal of each bat that passed by the detectors. As a community the Norfolk citizen acted together by participating in public scientific research. This happened to be a goal of Dr. Stuart Newson, who believed this “could feed into local conservation action plans and policy decisions… and increase community interest and involvement in bat monitoring” (Newson, 2014)

Collaborative community science projects such as the one in Norfolk can serve as a prototype for citizen science data analysis. An article in the Journal of Mammalogy by Dr. M. B. Fenton with Carleton University mentioned they searched 15 years for the L.cinereus species of bat. Although the researchers founded the L.cinereus species abundantly through echolocation, they could never capture them. I propose with the help of citizens in the area, the researchers could capture and study of the L.cinereus species with a quicker time frame. Imagine the amount of discoveries they could have made if they captured a rare species of bat. Additionally, the tremendous amount of time and resources they could have saved.

Although citizen science data is great for research projects, there can be errors and bias due to the variability in ability, experience, and type of training with the citizens aiding in projects. Though these concerns are valid, I feel researchers can utilize intense screening to filter out highly erroneous data. I also suggest researchers develop a strict training program for the citizens who want to take part of the study. This idea was shown in a study published in Biological Conservation by Dr. K. E. Barlow of Bat Conservation Trust. The authors recognizes data collection from citizen science can lead to quality and sampling bias. They stress “training of volunteers and use of standardized methods have been identified as crucial to the success of volunteer surveys” (Barlow et al., 2015).

The beauty of citizen science lies in the fact that anyone can take part of science. For the many bat colonies that exist amongst human populations, citizen science can further the involvement to protect and keep the public aware of bat ecology. Furthermore, the scientist that educate the world on the bat population can use the data gathered by citizens to push lawmakers to do something about our little winged friends. With citizen science anyone can be that beloved superhero for the bat species in their area.

Literature Cited

Barlow, K. E., Briggs, P. A., Haysom, K. A., Hutson, A. M., Lechiara, N. L., Racey, P. A., … & Langton, S. D. (2015). Citizen science reveals trends in bat populations: The national bat monitoring programme in Great Britain. Biological Conservation182, 14-26.

Fenton, M. B., Tennant, D. C., & Wyszecki, J. (1987). Using echolocation calls to measure the distribution of bats: the case of Euderma maculatum. Journal of Mammalogy, 142-144.

Newson, S. E., Evans, H. E., & Gillings, S. (2015). A novel citizen science approach for large-scale standardised monitoring of bat activity and distribution, evaluated in eastern EnglandBiological Conservation191, 38-49.

Newson, Stuart E.. (2014, June 13) The Norfolk Bat Survey – Dr Stuart Newson (BTO) . Retrieved from

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We Can’t Clam Up Anymore: Giant Clam Conservation Must Be Addressed in French Polynesia

A palette of cool, colorful hues light up the waters of Tatakoto Atoll, part of the Tuamotu island network, in French Polynesia. Until December 2008, the only giant clam to inhabit French Polynesia—Tridacna maxima—was abundant in all of its blue, purple, and green glory. In early 2009, white and empty clam shells occupied the once vibrant ocean floor. In 2013, researcher Serge Anréfouët of Institut de Recherche pour le Développement and colleagues authored a paper in the journal Biological Conservation, which stated that the T. maxima population density decreased by 83% during that span of several months (Andréfouët et al., 2013). What could possibly be responsible for such a large loss, within mere months? Andréfouët and colleagues set out to determine the cause of this mysterious population loss, as well as formulate conservation strategies to prevent future giant clam die-offs in French Polynesia.

The population loss, though large (roughly 20 million clams in 2004 decreased to 1.9 million clams in 2012), surprisingly went unnoticed by the local population. The appearance of field clues (e.g. smaller size structures and recruitment loss) pointed to evidence of mass mortality. Andréfouët and colleagues proposed that the mortality occurred roughly three years before their 2012 survey, due to the shortage of smaller individuals (i.e. less than 6cm). This deficit indicates a loss of recruitment for the past three years.

Since 2004, there has been a no-take area, the first of its kind in all of French Polynesia. The population loss affected all of the atoll, no-take area and all. Therefore, overfishing was eliminated as a cause of the die-off, since the giant clams were dying both in and out of the no-take area, as well as the nature of non-intense local hunting of clams. Additionally, pollution was eliminated as a cause because Tatakoto has no large source of land-based pollution.

A second explanation for the mass mortality is environmental factors. For example, El Niño Southern Oscillation (ESNO) causes increased sea surface temperature and lowered sea levels, both of which have major consequences for giant clams. Lowered sea levels expose the clams for an unusually long time, resulting in the clams drying out and dying. The increased sea surface temperatures also affect giant clams negatively because giant clams, like coral, contain zooxanthellae, a symbiotic micro-algae. Without this, corals are considered to be “bleached,” due to the white color left when the organism is driven out by physical or thermal stress. Perhaps extreme sea temperature led to the loss of symbiosis with zooxanthellae, leading the clams to have an eerie, white appearance.

A third explanation suggested in Andréfouët and colleagues is an unconfirmed report of bivalve mortalities from blooms of cyanobacteria Lyngbia majuscule. It is unclear whether this mortality occurred because of the cyanobacteria’s toxicity or a decrease in light from massive blooms.

Another threat to giant clams that can lead to their death is ocean acidification. Ocean acidification occurs when CO2 reacts to form carbonic acid, which in turn lowers the ocean’s pH. A 2015 PloS ONE study by researcher Sue-Ann Watson of James Cook University showed th that elevated levels of CO2 reduced survival and growth in giant clam T. squamosal juveniles (Watson, 2015). Just how bad are the effects of CO2 on our oceans? According to ocean acidification expert Dr. Sue-Ann Watson, “by the end of the century, if we carry on with business as usual [CO2 production], [oceans] will be 150 percent more acidic than they were 250 years ago” (DelViscio, 2014).

With all of these possible explanations, Andréfouët and his colleagues have yet to discover the exact causal mechanism for the massive die-off. Despite this, the study uses the potential causes of mortality to formulate a possible solution for management.

Overall, Andréfouët and colleagues suggest a new management design in which a “common set of conservation objectives” is established for the network of islands, rather than for an individual-island approach (Andréfouët et al., 2013). They suggest this new approach because working together as an island network can result in measures such as nationwide stock maintenance (which would promote long-term sustainability of T. maxima stocks in the case of mortality), and systematic co-monitoring by communities and scientists to monitor local physical and clam population parameters, as well as standing stock.

Critics of this nationwide support network may argue that there is not enough local attention paid towards the individual islands, and too much focus on a national scale goal, which can result in compliance issues. However, if populations continue to decline after environmental effects as they did in 2009, we are facing additional future mass mortalities. A nationwide support network, as suggested by Andréfouët and colleagues, could help prevent these die-offs by having stock maintenance and a nationwide network of giant clam spat-collecting structures (spat is the stage in which when a free-swimming oyster larva attaches to a hard substrate).

Though more research will be needed to determine the exact mechanism that led to the die-off, the benefits and importance of Tridacna maxima to both French Polynesia and marine ecosystems as a whole (e.g. coral reefs), such as being a food source and shelter for fish (Neo et al. (2014), prove that we cannot allow further mass mortalities to occur. As Andréfouët and colleagues suggest,  new management design for the network of islands in the Tuamotu network, rather than atoll-specific design is needed to prepare for environmental events and restore clam stocks if needed.

Giant clams of many colors offer beauty, among other benefits, to the marine ecosystem of French Polynesia. “Both Palmyra Atoll and Kingman Reef National Wildlife Refuge are home to rare giant clams” by Amanda Pollock / USFWS is licensed under CC 2.0

Giant clams of many colors offer beauty, among other benefits, to the marine ecosystem of French Polynesia.
“Both Palmyra Atoll and Kingman Reef National Wildlife Refuge are home to rare giant clams” by Amanda Pollock / USFWS is licensed under CC 2.0


Andréfouët, Serge, Simon Van Wynsberge, Nabila Gaertner-Mazouni, Christophe Menkes, Antoine Gilbert, and Georges Remoissenet. “Climate Variability and Massive Mortalities Challenge Giant Clam Conservation and Management Efforts in French Polynesia Atolls.” Biological Conservation 160 (2013): 190-99. Web. 15 Sept. 2015.

Delviscio, Produced Jeffery, Jessie Dewitt, Claire Maldarelli, and Larry Buchanan. “On the Cusp of Climate Change.” The New York Times. The New York Times, 21 Sept. 2014. Web. 22 Oct. 2015. <;.

Neo, Mei Lin, William Eckman, Kareen Vicentuan, Serena L.-M. Teo, and Peter A. Todd. “The Ecological Significance of Giant Clams in Coral Reef Ecosystems.” Biological Conservation 181 (2015): 111-23. Web. 21 Oct. 2015. <;.

Pollock, Amanda. Both Palmyra Atoll and Kingman Reef National Wildlife Refuge Are Home to Rare Giant Clams by Amanda Pollock / USFWS. 2010. Flikr, n.p.

Watson S-A (2015) Giant Clams and Rising CO2: Light May Ameliorate Effects of Ocean Acidification on a Solar-Powered Animal. PLoS ONE 10(6): e0128405. doi:10.1371/journal.pone.0128405

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Privacy Please: How Your Morning Commute may be Interrupting Fish Sex

We have all experienced that most irksome of annoyances: unnecessary noise. That car alarm going off at 2am, the not-so-quiet chatter during a test, basically anything your upstairs neighbors do. But for none has background noise been so arduous as for the Blacktail Shiner, a species of freshwater minnow.

“Stream” by Joshua Crauswell is licensed under CC 4.0

Stream” by Joshua Crauswell is licensed under CC 4.0

As it turns out, the Blacktail Shiners of the American southeast are going hoarse trying to yell over our human racket. Male Shiners produce sounds to attract mates and protect their territories. But the natural soundscape in which Shiners evolved is being tainted by traffic noise from overpass bridges. All this unnatural clatter is messing with the male Shiners’ game, as it prevents females from receiving and interpreting his mating calls. So those noisy neighbors we all hate? That’s us for the Blacktail Shiner.

Of course, nature is full of noisiness from both living and environmental sources. Many animals have worked around this natural clamor by finding ‘quiet windows’ in the spectrum of sound wave frequencies in which little noise occurs. Like with radio, species that use noise for communication find a free frequency slot in which to set up their own clear station. This is exactly what the Blacktail Shiner has done. But a recent study in Biological Conservation shows that traffic noise, specifically from semi-trailer trucks, interferes with the Blacktail Shiner station.

Researchers set up underwater sound recorders called hydrophones to record three different noise measurements: the natural ambient noise, human-caused background noises, and Shiner calls. Natural ambient noise was recorded near suitable breeding habitats in which Shiners could perform mating rituals. But most importantly, such habitats remained uncontaminated by human ruckus. When compared with Shiner calls recorded in the lab, the natural ambient noise did indeed show a gap where the Shiner frequencies fit in.

When traffic noises were added to the mix, the quiet window was no longer quite so quiet, as these frequencies overlapped with those of the Shiner calls. Outside noises infiltrating the quiet window that Shiners utilize means that these fish can no longer hear each other properly. Female Shiners can’t catch the sexy growls of viable suitors, and males may be less able to detect the ‘knocks’ produced by rivals near their nests. As Auburn University researchers Daniel Holt and Carol Johnston mention in their Biological Conservation article, “recovery to the natural soundscape may be as far as 12,113 m” from a traffic bridge. Just as with all other forms of pollution, the mal-effects of our noisiness spread far from the source.

But the male Shiners aren’t giving up so easy. Blacktail Shiners display a reflex known as the Lombard Effect. We’ve all experienced this effect before: when background noises get louder, we compensate by doing the same. Nature’s loudness fluctuates, and Shiners can deal with this by simply speaking up. So they should be able to do the same with human noise, right?

However, even with the Lombard Effect, traffic noise is making male Shiners look bad. The growls that males produce to attract females are made up of many different factors that each relay information about the male’s overall condition. For example, the duration of the growl seems to be correlated to the quality of the male. Females may choose to entertain certain suitors over others based on such quality parameters. But if traffic noise masks part of the duration of growls, females may move on without choosing a mate.

The issue of noise pollution doesn’t just affect Blacktail Shiners. Many other fish, some much more endangered, utilize quiet windows in similar ways. Our clamor could be detrimental to their reproductive success, especially since peak fish spawning times often overlap with morning rush hours. Co-author Carol Johnston warns that these “impacts, combined with others such as habitat degradation, can alter ecosystem function.  From a human perspective, this can impact ecosystem services such as water quality and important food fisheries.” So if we want these aquatic neighbors to stick around, we may need to keep it down.


Holt, Daniel E., and Carol E. Johnston. “Traffic Noise Masks Acoustic Signals of Freshwater Stream Fish.” Biological Conservation 187 (2015): 27-33. Accessed September 14, 2015.

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