How Invasive Crayfish Help More Mosquitoes Thrive

iStock
iStock

When invasive species somehow find their way into an environment where they don’t belong, they can disrupt everything from the food web to public health.

Recently, researchers at UCLA and other California institutions discovered an unwelcome squatter that might directly affect the spread of mosquito-borne disease. It’s the red swamp crayfish, a tasty delicacy often found in gumbo that may also be allowing mosquito populations to thrive.

Native to the southeastern U.S., the crayfish are now found in California. While investigating their damaging ecological presence, scientists made a chilling observation: In streams where crayfish concentrations were high, there was a noticeable spike in the number of mosquito larvae. They found something else, too—a sharp decline in the larvae-eating dragonfly nymphs that they would expect to see in the area.

In the paper, published in Conservation Biology, lead author Gary Bucciarelli observed 13 streams in the Santa Monica Mountains. Eight had crayfish populations and were high in mosquito larvae but low on dragonfly nymphs. Five crayfish-free streams had more nymphs and fewer larvae.

In a lab experiment putting the crayfish, mosquitoes, and dragonflies in proximity, Bucciarelli watched as the dragonfly nymphs—normally happy to prey on mosquito larvae—kept their distance in the presence of crayfish, apparently spooked by the crustaceans. In the wild, high concentrations of crayfish appear to be interrupting the dragonflies' hunting habits, allowing more mosquitoes to roam unchecked.

That’s not great news for humans. Mosquitoes are notorious for spreading viral diseases like West Nile, Zika, and malaria. In Los Angeles, where the mosquito population could conceivably get a boost, 15 of the 16 mosquito species can harbor pathogens that pose a threat to public health.

No one is quite sure how crayfish spread to the area—it’s possible fishermen used them as bait decades ago—but it's likely their presence will continue interfering with native species. In 2015, a nonprofit backed by the California Department of Fish and Wildlife started removing crayfish from the Santa Monica streams using traps set by volunteers. The captured crayfish were sent to Malibu to become snack fodder for opossums and raccoons. But it’s a sizable task. Roughly 600 crayfish might be caught in a given day out of the millions thought to inhabit the waters.

Conservationists might soon pursue more aggressive means to combat the crayfish's damaging ecological footprint. In addition to scaring dragonflies into inaction, they can threaten the integrity of underwater dams by burrowing and consume plants that help purify the water.

h/t National Geographic]

These Nature Posters Show the Most Endangered Animal in Each State

NetCredit
NetCredit

The U.S. has more than 1300 endangered or threatened species, from South Dakota's black-footed ferret to Colorado's Uncompahgre fritillary butterfly to the blue whales that live off the coast of Alaska. These wild animals could disappear if prompt wildlife conservation measures aren't taken, and people are largely to blame. Globally, human activities are the direct cause of 99 percent of threatened animal classifications, according to the Center for Biological Diversity.

Some of these animals may even be in your backyard. A research team commissioned by NetCredit used data from the U.S. Fish and Wildlife Service to highlight the most endangered animal in each state. For this project, "most endangered" refers to the animals that face the greatest risk of extinction. An art director and designer then teamed up to create gorgeous illustrations of each animal.

Since some regions are home to many of the same creatures, a different animal was selected from the shortlist of endangered species in cases where there were duplicates from one state to the next. The goal was to cast light on as many threatened species as possible, including the ones that rarely make headlines.

"We hope this will start a conversation around the fact that it's not just the iconic species we see on nature documentaries that we're at risk of losing forever," the research team said in a statement.

Take the black-footed ferret, for instance. It's the only ferret that's native to North America, but its ranks have dwindled as its main food source—prairie dogs—becomes harder to find. Prairie dog eradication programs and loss of the ferret's habitat (due to farming) are some of the factors to blame. A ferret breeding colony was established in the past, but only 200 to 300 of the animals still remain, rendering them critically endangered.

To learn more about some of America's most at-risk species, check out the posters below and visit NetCredit's website for the full report.

California's Point Arena mountain beaver
NetCredit

Alaska's blue whale
NetCredit

South Carolina's frosted flatwoods salamander
NetCredit

Minnesota's rusty patched bumble bee
NetCredit

New York's Eastern massasauga snake
NetCredit

West Virginia's Virginia big-eared bat
NetCredit

Florida's red wolf
NetCredit

The poster of endangered wildlife in all 50 states
NetCredit

The West Coast Is Preparing for Another Super Bloom

iStock.com/Ron_Thomas
iStock.com/Ron_Thomas

In spring of 2017, people flocked to Southern California's deserts to see fields of wildflowers brightening the normally sparse terrain. That level of vegetation, also known as a super bloom, is an event that only occurs after winters of heavier-than-average precipitation. Now just two years later, the rare sight is about to return to California's Anza-Borrego desert, the Los Angeles Times reports.

The 2018/2019 winter season was an unusually wet one for California. Between October 1 and the beginning of February, Downtown Los Angeles saw 12.91 inches of rain, which is approximately 167 percent more than the seasonal average. All that precipitation will produce an explosion of color when spring arrives in Anza-Borrego desert three hours southeast of Los Angeles. Experts predict the 2019 super bloom could start as early as late February and last through March.

If the last super bloom is any indication, this year's event will attract crowds of sight-seers. Anywhere from 250,000 to 500,000 people visited the desert to look at and snap pictures of the flowers in 2017. Many local communities were overwhelmed by the influx of tourists, but this time around they know what to expect. Portable toilets will be set up around popular sites, and thousands of maps of showing where the flower fields, gas stations, and toilets are located are ready to be passed out to drivers.

Visitors also have a few things to learn from the past super bloom. Two years ago, foot traffic in places like the Antelope Valley California Poppy Reserve was so heavy that trails had to be closed down to protect delicate flowers from selfie-taking tourists.

[h/t Los Angeles Times]

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