Quantcast
Animals
Sea otters in Elkhorn Slough, CA, an area of salt marshes and seagrass beds not usually considered their habitat. Judy Gallagher / Flickr / CC BY 2.0

Sea Otters, Alligators and Other Major Predators Are Reclaiming Historic Niches, Study Finds

Increasingly, large predators like mountain lions, alligators and killer whales are moving into ecosystems not traditionally associated with them. Mountain lions have been spotted prowling grasslands, alligators have been seen lounging on Florida beaches and killer whales have been spied swimming in freshwater rivers.

Many hypothesized that the animals were taking over new territories as their populations rebounded due to conservation efforts. But research published in Current Biology Monday suggests that they are actually taking back what was rightfully theirs.


The researchers looked specifically at sea otters on the Pacific coast of the U.S., who have expanded from kelp forests to estuaries, salt marshes and seagrass beds, and alligators in the Southeastern U.S., who have expanded from freshwater swamps into marine habitats like mangroves and seagrasses. The researchers argued, based on both the species' success in these "new" habitats when protected from human interference, as well as historical and archaeological evidence placing both sea otters and alligators in coastal marshes, that the predators were reconquering ground they had occupied before human activity drove them out.

"We can no longer chock up a large alligator on a beach or coral reef as an aberrant sighting," study co-author and Rachel Carson associate professor of Marine Conservation Biology at Duke's Nicholas School of the Environment Brian Silliman said in a Duke University press release. "It's not an outlier or short-term blip. It's the old norm, the way it used to be before we pushed these species onto their last legs in hard-to-reach refuges. Now, they are returning," he said.

The study's authors, who, in addition to Duke, came from the University of California Santa Cruz, the U.S. Geological Survey, the University of Florida and Kansas State University, suggested that the same might be true of other large predators moving into new niches, though more research needs to be conducted to confirm this hypothesis.

Examples of other potential reconquests include the movement of orangutans into disturbed forests, river otters into marine wetlands, canines like wolves and coyotes onto beaches and rocky shores and grey, harbor and harp seals from Arctic into subtropical waters.

Taken together, these movements also indicate that large predators are more adaptive than ecologists thought.

"The assumption, widely reinforced in both the scientific and popular media, is that these animals live where they live because they are habitat specialists. Alligators love swamps; sea otters do best in saltwater kelp forests; orangutans need undisturbed forests; marine mammals prefer polar waters. But this is based on studies and observations made while these populations were in sharp decline. Now that they are rebounding, they're surprising us by demonstrating how adaptable and cosmopolitan they really are," Silliman said in the press release.

This is good news for both predators and the ecosystems they are calling home again.

In the press release, Stillman used the example of sea otters' movement into estuaries. This habitat flexibility will help sea otters survive as kelp forests are threatened due to climate change. But it also helps estuaries, because the sea otters eat Dungeness crabs who otherwise eat too many of the sea slugs that prevent the estuaries from being overrun by epiphytic algae fertilized by urban and agricultural runoff.

The study's conclusion argued that its findings should be taken into consideration when determining conservation policy.

"As many of these consumers (and their habitats) are protected and managed by legislation, the habitats they are now re-colonizing (e.g., salt marshes) will also need to be considered as critical habitat in recovery plans. Indeed, as is the case with sea otters and alligators, these 'novel' ecosystems can potentially support much higher populations than current habitats listed as critical," the study's authors wrote.

Show Comments ()

EcoWatch Daily Newsletter

Sponsored
Animals
Mom and baby West Indian manatees in Three Sisters Springs, Florida. James R.D. Scott / Getty Images

Florida Manatee: 10% of Population Could Be Wiped Out This Year

2018 has not been a good year for Florida's iconic manatees. A total of 540 sea cows have died in the last eight months, surpassing last year's total of 538 deaths, according to figures posted Monday by Public Employees for Environmental Responsibility (PEER).

The figure will likely climb higher before the year's end amid the state's ongoing toxic algae crisis. The red tide in the state's southwest is the known or suspected cause of death for 97 manatees as of Aug. 12, the Florida Fish & Wildlife Conservation Commission recently reported.

Keep reading... Show less
Health
SOPA Images / Getty Images

Walmart Joins Ranks of Retailers Pulling Toxic Paint Strippers From Shelves – When Will EPA Follow Suit?

By Sarah Vogel

Monday, Walmart announced that it will stop selling paint strippers containing methylene chloride or N-methylpyrrolidone (NMP) in stores by February 2019—making it the first general merchandise retailer to take such action. Walmart's announcement follows the strong leadership demonstrated by Lowes, Home Depot and Sherwin Williams, all of which have committed not to sell methylene chloride- and NMP-based paint stripping products by the end of the year. Importantly, Walmart's action goes beyond its U.S. stores, including those in Mexico, Canada and Central America, as well as their online store.

Keep reading... Show less
Animals
Seal #108, left, and a small pup named "Premie" swim up to the edge of their pool for their 3 p.m. feeding at the Marine Mammals of Maine rehabilitation center on Aug. 14. Brianna Soukup / Portland Press Herald via Getty Images

New England Seal Die-Off Could be Linked to Chemical Pollution

Researchers think a mysterious die-off of seals along the Maine coast could be linked to chemical pollution, the Portland Press Herald reported Sunday.

More than 400 dead or stranded seals have washed up on the Maine coast so far this year, more than in any of the past seven years, according to National Oceanic and Atmospheric Administration (NOAA) statistics.

Keep reading... Show less
Renewable Energy
Looking towards Livadia harbour on the Greek island of Tilos. Getty Images

Greek Island to Be First in Mediterranean to Power Itself With Only Wind and Solar

The Greek island of Tilos is set to be the first in the Mediterranean to power itself entirely with wind and solar power, The Associated Press reported Sunday.

The final tests of a new system that will allow the island to power itself with batteries recharged by a solar park and 800-kilowatt wind turbine are taking place this summer, and the system is expected to go live later this year.

Keep reading... Show less
Sponsored
Oceans
Wikimedia Commons / CC BY 3.0

Please Stop Flushing Your Contact Lenses

Contact lenses may appear harmlessly soft and small, but a big chunk of American users are improperly disposing their used lenses and adding to the planet's microplastic problem, Arizona State University researchers found.

In a survey of 409 wearers, about 1 in 5 responded that they flushed their used lenses down the toilet or sink instead of throwing them in the trash, according to a new study presented at the American Chemical Society's National Meeting and Exposition.

Keep reading... Show less
Health

Cell Phones in Schools? France Says No, San Francisco Educators Urge Caution

By Olga Naidenko

As the school year begins, the movement to exercise caution in students' use of cell phones and other wireless devices is gaining international momentum.

Keep reading... Show less
Sponsored
Climate
Breakthrough

'We Are Climbing Rapidly Out of Humankind's Safe Zone': New Report Warns Dire Climate Warnings Not Dire Enough

By Jon Queally

Offering a stark warning to the world, a new report out Monday argues that the reticence of the world's scientific community—trapped in otherwise healthy habits of caution and due diligence—to downplay the potentially irreversible and cataclysmic impacts of climate change is itself a threat that should no longer be tolerated if humanity is to be motivated to make the rapid and far-reaching transition away from fossil fuels and other emissions-generating industries.

Keep reading... Show less
Popular
Pxhere

Trump Power Plant Plan Will Significantly Increase CO2 Pollution

The Trump administration is expected on Tuesday to propose a major rollback of the Clean Power Plan, President Obama's signature climate policy.

The replacement will relax rules for coal-fired plants and will very likely increase air pollution and planet-warming carbon dioxide emissions.

Keep reading... Show less
Sponsored

mail-copy

The best of EcoWatch, right in your inbox. Sign up for our email newsletter!