Will Climate Change Push These Amphibians to the Brink?
By Tara Lohan
Aerial photos of the Sierra Nevada — the long mountain range stretching down the spine of California — showed rust-colored swathes following the state's record-breaking five-year drought that ended in 2016. The 100 million dead trees were one of the most visible examples of the ecological toll the drought had wrought.
Now, a few years later, we're starting to learn about how smaller, less noticeable species were affected.
One of those is the California newt (Taricha torosa). These large, colorful amphibians live across the state, from Mendocino County to San Diego County, but newts living in Southern California fared worse during the drought, according to a new study published in the Nature journal Scientific Reports. And worse, anticipated future changes to the climate are likely to put northern newts in the same boat in coming decades.
Researchers have been surveying populations of these amphibians for decades. By tagging them with transponders and following their movements, they've learned that the newts can live for more than 30 years and return to the same spots year after year as they migrate between freshwater and land.
But as the drought began in 2012, the researchers noticed a change in the Southern Californian populations. There were fewer newts from the tagged population coming back to dozens of breeding sites monitored across the region each year. The researchers also observed fewer egg masses, tadpoles and larvae.
"Here's a long-lived species that we're not seeing individuals that we've seen for the last 10 or 15 years coming back to the sites where they usually breed," says Gary Bucciarelli, the lead author of the report and an assistant adjunct professor of ecology and evolutionary biology at UCLA.
And there was one more piece of bad news: Most of the adult newts that did return in Southern California were in poorer body condition than before the drought began. This negative trend, the researchers concluded, was linked to drier and warmer conditions that were far outside the 100-year average.
At the time the state was experiencing drought conditions not seen there for 1,200 years. You'd expect drought to hurt amphibians, which rely on access to water, but Bucciarelli says the research shows that similarly record-high air temperatures may have played an even greater role than precipitation.
Warmer temperatures remove necessary moisture from the terrestrial environment. But they could also affect food — a shifting climate may mean less prey, says Bucciarelli. Or it could mean that newts spend more time wandering around, burning calories, and less time hunkered down as they normally would.
Whatever exactly happened in this case, "It all was strongly correlated with the extreme deviation in climate," he adds.
Amphibians spend part of the year on land, and we know far less about how they spend their terrestrial days. "When they're on land we don't know if they're underground, moving around, in a deep sleep, or what they're feeding on," he says. "This research suggests there are things happening on land that are impacted by temperature that we don't really understand."
One thing is certain, though: Climate change will bring more severe droughts and higher temperatures to California, and that could push newts in Southern California, which are already a species of conservation concern, closer to extinction.
And in the next 50 years, the northern populations are likely to experience the same change in body condition. That means that the northern range "likely will not provide climate refuge for numerous amphibian communities," the researchers conclude.
That's particularly bad news considering that globally, an estimated 40% of amphibians face extinction. A disease caused by chytrid fungus has devastated many amphibian populations, especially in Australia, Central and South America, and wiped out 90 species already.
But amphibians face other threats, too. And the California newt is no exception.
The species is adapted to drought, but "they haven't dealt with drought coupled with temperature changes that are this rapid and this severe, in conjunction with habitat fragmentation, land use changes and fire frequency changes," Bucciarelli says. "Now we're beginning to see how these combined stressors are acting out ecologically."
So what do we do?
Collecting more data is a good start. Land managers need to begin long-term monitoring surveys of populations of amphibians now, even if the species aren't currently a major concern. "You never know what's going to happen and having baseline data is super important," he says.
Proactively improving habitat is also critical. We can start by ensuring that habitats are free of non-native species, says Bucciarelli, who has also tracked the negative effects of introduced fish and invasive crayfish on amphibians.
Suitable habitat is key, but so is connection. Many newt populations in Southern California have become islands, separated by development that limits their genetic diversity — and in the long run, their capacity to adapt to rapidly changing environmental conditions. Ensuring habitat connectivity could help strengthen their resilience.
Even if all of that happens, climate change will continue to be a threat, and Bucciarelli says we may need to develop contingency plans for worsening conditions if we hope to save these newts.
"We'll have to think of different and more creative management strategies to help in years when temperature and precipitation are not in line with the norm."
Reposted with permission from our media associate The Revelator.
Maryland will become the first state in the nation Thursday to implement a ban on foam takeout containers.
- New Jersey Legislature Passes 'Most Comprehensive' Plastics Ban ... ›
- Canada to Announce Ban on Single-Use Plastics - EcoWatch ›
- The Complex and Frustrating Reality of Recycling Plastic - EcoWatch ›
- Dunkin' Says Bye to Foam Cups (But Bring Your Own Thermos ... ›
- Maine and Vermont Pass Plastic Bag Bans on the Same Day ... ›
EcoWatch Daily Newsletter
By Ajit Niranjan
Leaders from across the world have promised to turn environmental degradation around and put nature on the path to recovery within a decade.
- Destruction of Nature Is Triggering Pandemics, Say Leaders of WWF ... ›
- The UN Wants to Protect 30% of the Planet by 2030 - EcoWatch ›
- New WWF Report Calls for Protecting Nature to Prevent Future ... ›
Just days after a new report detailed the "unequivocal and pervasive role" climate change plays in the increased frequency and intensity of wildfires, new fires burned 10,000 acres on Sunday as a "dome" of hot, dry air over Northern California created ideal fire conditions over the weekend.
- California's Iconic Redwoods Threatened by Wildfires - EcoWatch ›
- California Wildfires Destroy Condor Sanctuary, at Least 4 Birds Still ... ›
- 7 Devastating Photos of Wildfires in California, Oregon and ... ›
- David Attenborough Calls For Ban on Deep-Sea Mining - EcoWatch ›
- Sir David Attenborough Set to Present BBC Documentary on ... ›
- David Attenborough Gives Stark Warning in New BBC Climate ... ›
Kevin T. Smiley
When hurricanes and other extreme storms unleash downpours like Tropical Storm Beta has been doing in the South, the floodwater doesn't always stay within the government's flood risk zones.
New research suggests that nearly twice as many properties are at risk from a 100-year flood today than the Federal Emergency Management Agency's flood maps indicate.
Flooding Outside the Zones<p>About <a href="https://furmancenter.org/files/Floodplain_PopulationBrief_12DEC2017.pdf" target="_blank">15 million</a> Americans live in FEMA's current 100-year flood zones. The designation warns them that their properties face a 1% risk of flooding in any given year. They must obtain flood insurance if they want a federally ensured loan – insurance that helps them recover from flooding.</p><p>In Greater Houston, however, <a href="https://doi.org/10.1111/j.1539-6924.2012.01840.x" target="_blank">47% of claims</a> made to FEMA across three decades before Hurricane Harvey were outside of the 100-year flood zones. Harris County, recognizing that FEMA flood maps don't capture the full risk, now <a href="https://www.hcfcd.org/floodinsurance" target="_blank" rel="noopener noreferrer">recommends that every household</a> in Houston and the rest of the county have flood insurance.</p><p>New risk models point to a similar conclusion: Flood risk in these areas outstrips expectations in the current FEMA flood maps.</p><p>One of those models, from the <a href="https://firststreet.org/flood-lab/research/2020-national-flood-risk-assessment-highlights/" target="_blank">First Street Foundation</a>, estimates that the number of properties at risk in a 100-year storm is 1.7 times higher than the FEMA maps suggest. Other <a href="https://doi.org/10.1088/1748-9326/aaac65" target="_blank" rel="noopener noreferrer">researchers</a> find an even higher margin, with 2.6 to 3.1 times more people exposed to serious flooding in a 100-year storm than FEMA estimates.</p>
What FEMA’s Flood Maps Miss<p>Understanding why areas outside the 100-year flood zones are flooding more often than the FEMA maps suggest involves larger social and environmental issues. Three reasons stand out.</p><p>First, some places rely on relatively old FEMA maps that don't account for recent urbanization.</p><p>Urbanization matters because impervious surfaces – think pavement and buildings – are not effective sponges like natural landscapes can be. Moreover, the process for updating floodplain maps is locally variable and can take years to complete. Famously, New York City was updating its maps when Hurricane Sandy hit in 2012 but hadn't finished, meaning flood maps in effect <a href="https://projects.propublica.org/nyc-flood/" target="_blank">were from 1983</a>. FEMA is required to assess whether updates are needed every five years, but the <a href="https://www.fema.gov/cis/nation.html" target="_blank" rel="noopener noreferrer">majority of maps</a> <a href="https://www.oig.dhs.gov/sites/default/files/assets/2017/OIG-17-110-Sep17.pdf" target="_blank" rel="noopener noreferrer">are older</a>.</p><p>Second, binary thinking can lead people to an underaccounting of risk, and that can mean communities fail to take steps that could protect a neighborhood from flooding. The logic goes: if I'm not in the 100-year floodplain, then I'm not at risk. Risk perception <a href="https://doi.org/10.1088/1748-9326/ab195a" target="_blank" rel="noopener noreferrer">research</a> backs this up. FEMA-delineated flood zones are the major factor shaping flood mitigation behaviors.</p><p>Third, the era of climate change scuttles conventional assumptions.</p><p>As the planet warms, extreme storms are becoming <a href="https://nca2018.globalchange.gov/" target="_blank">more common and severe</a>. If greenhouse gas emissions continue to increase at a high rate, computer models suggest that the chances of a severe storm dropping 20 inches of rain on Texas in any given year will increase from about 1% at the end of the last century to 18% at the end of this one, a chance of <a href="https://doi.org/10.1073/pnas.1716222114" target="_blank" rel="noopener noreferrer">once every 5.5 years</a>. So far, <a href="https://www.rstreet.org/wp-content/uploads/2020/02/195.pdf" target="_blank" rel="noopener noreferrer">FEMA hasn't taken into account the impact climate change is having</a> on extreme weather and sea level rise.</p>
Racial Disparities in Flooding Outside the Zones<p>So, who is at risk?</p><p>Years of research and evidence from storms have highlighted social inequalities in areas with a high risk of flooding. But most local governments have less understanding of the social and demographic composition of communities that experience flood impacts outside of flood zones.</p><p>In analyzing the damage from Hurricane Harvey in the Houston area, I found that <a href="https://doi.org/10.1088/1748-9326/aba0fe" target="_blank">Black and Hispanic residents disproportionately experienced flooding</a> in areas beyond FEMA's 100-year flood zones.</p><p>With the majority of flooding from Hurricane Harvey occurring outside of 100-year flood zones, this meant that the overall impact of Harvey was racially unequal too.</p><p>Research into where flooding occurs in Baltimore, Chicago and Phoenix points to some of the potential causes. <a href="https://www.nap.edu/read/25381/chapter/4#16" target="_blank" rel="noopener noreferrer">In Baltimore and Chicago</a>, for example, aging storm and sewer infrastructure, poor construction and insufficient efforts to mitigate flooding are part of the flooding problem in some predominantly Black neighborhoods.</p>
What Can Be Done About It<p>Better accounting for those three reasons could substantively improve risk assessments and help cities prioritize infrastructure improvements and flood mitigation projects in these at-risk neighborhoods.</p><p>For example, First Street Foundation's risk maps account for <a href="https://firststreet.org/flood-lab/research/flood-model-methodology_overview/" target="_blank">climate change</a> and present <a href="https://floodfactor.com/" target="_blank" rel="noopener noreferrer">ratings</a> on a scale from 1 to 10. FEMA, which works with communities to update flood maps, is <a href="https://www.fema.gov/media-library-data/1521054297905-ca85d066dddb84c975b165db653c9049/TMAC_2017_Annual_Report_Final508(v8)_03-12-2018.pdf" target="_blank" rel="noopener noreferrer">exploring rating systems</a>. And the National Academies of Sciences, Engineering and Medicine recently <a href="https://www.nationalacademies.org/news/2019/03/new-report-calls-for-different-approaches-to-predict-and-understand-urban-flooding" target="_blank" rel="noopener noreferrer">called for a new generation of flood maps</a> that takes climate change into account.</p><p>Including recent urbanization in those assessments will matter too, especially in fast-growing cities like Houston, where <a href="https://authors.elsevier.com/a/1boBRyDvMFW6W" target="_blank" rel="noopener noreferrer">386 new square miles</a> of impervious surfaces were created in the last 20 years. That's greater than the land area of New York City. New construction in one area can also <a href="https://scalawagmagazine.org/2018/01/city-in-a-swamp-as-houston-booms-its-flood-problems-are-only-getting-worse/" target="_blank" rel="noopener noreferrer">impact older neighborhoods downhill</a> during a flood, as some Houston communities discovered in Hurricane Harvey.</p><p>Improving risk assessments is needed not just to better prepare communities for major flood events, but also to prevent racial inequalities – in housing and beyond – from <a href="https://www.npr.org/2019/03/05/688786177/how-federal-disaster-money-favors-the-rich" target="_blank" rel="noopener noreferrer">growing</a> after the unequal impacts of disasters.</p>
- Overlooked Flood Risk Endangers Homeowners - EcoWatch ›
- Florida Coastal Flooding Maps: Residents Deny Predicted Risks to ... ›
- Flooding Risk for U.S. Homes: Millions More Are Vulnerable Than ... ›