Category: Endangered Species

A small and unpretentious fish is sending a warning message

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Photo credit: USFWS by Steve Martarano / CC BY 2.0
Photo credit: USFWS by Steve Martarano / CC BY 2.0

A vanishing number of Delta smelt in San Francisco Bay is finding a changing climate contributing to its declining numbers.

By Hanisha Harjani, Yale Climate Connections (CC BY-NC-ND 2.5)

Deep in the San Francisco Bay, two rivers splinter into a vague triangle, creating one of the richest watersheds in California. This estuary – the Sacramento-San Joaquin River Delta – is an important source of freshwater for the 4 million folks who live in the region. Local agricultural, fishing, and recreation industries bring in billions of dollars a year, and the area also provides a rich habitat for local wildlife. 

Over the past few decades, this watershed has seen a dramatic change in its climate. Years-long droughts and record-high temperatures have transformed the region – a shift that’s told no better, perhaps, than through the story of the Delta smelt.

The Delta smelt is an iridescent fish about the size of a finger. The fish is a bioindicator, often noted for its distinct smell of fresh cucumbers. Though small in size, it has an impact reaching beyond the Delta, all the way to Capitol Hill. The smelt’s role in Northern California’s decades-long “water wars” have made it a key player in shaping the region’s water policy.

A harbinger of threats to other species

As a bioindicator, its presence in the Delta signifies a healthy ecosystem – one that can support a diverse range of life. However, not since the 1980s have the fish been abundant in the wild.

To Tien-Chieh Hung, PhD,  director of the Fish Conservation and Culture Laboratory (FCCL) at UC Davis, it’s simple: “If these fish are going extinct, then there are other species that are going to be listed as threatened or endangered, too.”

There was a time when these fish swam through the Delta in the thousands. Trawling surveys would pull up nets full of their thin, shimmering bodies. It’s now rare for these surveys to catch even one. 

In fact, the largest known population of Delta smelt doesn’t live in the Delta at all. They live, instead, just south of the watershed, in large white circular lab tanks Hung oversees at the FCCL, now rearing  a captive population in the tens of thousands.

This decades-long effort has been meticulous. The smelt was listed as threatened in 1993 but the project to culture the fish was established only a decade later, in 2004. Since then, FCCL scientists each year scour the estuary in search of wild smelt. Each such specimen found is then transported into the lab to be tagged and genetically cataloged. 

The careful genetic classification of each wild Delta smelt has been key to preserving the genetic diversity of the captive population to keep it as similar to the wild stock as possible. For years, when breeding season comes along, this genetic catalog is carefully consulted to pair-up smelt for mating new generations in the lab. But keeping this cultured population diverse has become harder over the past decade as finding wild smelt has become rarer in the estuary. 

The hard reality: In 2021, California’s Department of Fish and Wildlife’s Fall Midwater Trawl Survey found none at all, prompting scientists to do something they have been putting off for years – begin preparing for the first release of cultivated smelt into the wild.

A long troubling history, and now comes climate change

The Delta smelt raised in captivity do not smell much like cucumbers. Hung mentions that this trait seems to be connected to stress. The smelt at the FCCL have no predators, perfectly saline water, and plenty of food piped into their tanks. Their lives in the Delta are much less comfy.

Importantly, the Delta smelt evolved specifically in, and is named after, the ecosystem of the San Francisco Bay Delta, for thousands of years having an estuary with cool, freshwater running through its many channels. The watershed in modern times feels very different: According to scientist Peter Moyle, associate director of the Center for Watershed Sciences at UC Davis, “that [original] habitat just isn’t there.”

Irrevocable changes in the smelt’s ecosystem began in the 1800s. Non-native species – like the bluegill and largemouth bass – were introduced to the watershed for sportfishing. Fish very similar to the Delta smelt, like the silverside and wakasagi, were introduced soon after as supplemental food for these new game fish. The former meant more predation for the Delta smelt, the latter meant more competition. 

In addition to these new fish in the Delta, regional water programs like the Central Valley Project and the State Water Project began operating in the 1960s. These projects diverted water flows in the estuary to serve communities in Northern California and, consequently, turned the watershed more saline than brackish.

All of this, coupled with rising temperatures and consistently historic droughts in the region, have created a deadly Delta for the smelt; though this is also a reality for many estuaries, worldwide. “Climate change,” said Moyle, “has just accelerated things.”

The Delta smelt has a lifespan of only one year, and its population was initially devastated by a prolonged drought in the 80s. This time, however, recovery proved particularly difficult because conditions continued to worsen and some non-native species adapted to these changes better than the smelt. In past droughts, smelt populations have diminished even as populations of introduced silversides increased.

“We use the term regime shift,” said Brian Schreier, a scientist with the Department of Water Resources (DWR) in West Sacramento, about the smelt’s decline. And this regime shift was not so easy to reverse. Even as the conditions in the estuary worsened, millions of people still relied on these water projects to survive.

Steps leading to boosting number of smelt in the wild

In 2008, the US Fish & Wildlife Service (USFWS) issued a Biological Opinion (BiOp) that expanding the export of water from the Delta would severely impact the smelt population. That action mandated that measures, like reduced pumping, be taken to prevent such a future for the fish. That 2008 BiOp was reversed in 2019, however, when the Trump administration issued a new statement claiming that the smelt population would be fine given that the FCCL has spent decades rearing a robust captive population to supplement the wild fish.

Even though the FCCL’s plan has always been to eventually release these fish into the wild, scientists have resisted doing so for nearly 20 years. They expressed concerns that the captive population might not be fit for conditions in the wild, or that they would adversely impact the wild smelt population that is surviving.

Water and Power Law Group’s Natural Resource Counsel, Paul Kibel, recalls the way hatcheries failed at replacing salmon populations in a 2020 article “Salmon Lessons for the Delta Smelt.” “The replacement assumption has proven faulty,”  Kibel wrote, “as the total abundance of salmon declined at the same time the propagation and release of hatchery salmon has expanded.” In the case of the salmon, the replacement population not only increased competition for their wild counterparts, but they had also been domesticated in the hatchery and were unfit to survive in the wild. 

These were real concerns also for scientists working with the smelt. And though the 2019 BiOp placed excessive and perhaps unreasonable emphasis on the hatchery fish solution, it may have also – temporarily, at least – saved the Delta smelt.

“That was the first regulatory document that actually had legal backing,” said Schreier, “and effectively mandated that supplementation would occur.” And, late last year, for the first time ever, supplementation finally did.

‘A roller coaster’ as 12,000 hatchery smelts were reintroduced

December 15, 2021, marked the first release of hatchery Delta smelt into the wild. More than 12,000 of these fish were transported from their cool, roomy tanks in the FCCL and placed into several barrels in the back of a pick-up truck. They were then driven to Rio Vista where the barrels were transported to a boat and sailed into the channels of the Delta, where the fish were finally released together. 

The road to this release was “a roller coaster,” according to Schreier: It involved many months of experimental trial releases where select populations of hatchery fish were exposed to conditions of the Delta in aluminum cages specially designed to prevent their escaping even as  food and fresh water flowed through. 

“We started under what we thought would be the best conditions,” said Melinda Baerwald, an ecologist at the DWR, about the caged trials. “To be perfectly honest, we didn’t have high hopes.” But she says she was pleasantly surprised when this first trial had a nearly 100% survival rate of the captive smelt.

The research team then tried exposing the hatchery population to progressively worsening conditions to see how they would fare, another step that  proved reassuring. Baerwald recalls one of the last caged trials they did last summer. “It was fairly shocking,” she said.

The team took the smelt out to the Yolo Bypass in the middle of a heat wave. They weren’t expecting the smelt to stay alive for about a week. “But the fish kept surviving,” she said.

74 wild smelt is more than zero … but ‘a desperation measure’?

Since the first release in December, four more releases have occurred in two additional locations. And, since these releases have taken place, local trawling surveys have picked up 74 smelt, compared to the previous number of  consistently zero.

Baerwald and Schreier wanted these releases to take place in the wintertime to ensure the best chances of survival in the increasingly warming Delta. They also mentioned that doing the releases during cooler months allows the captive Delta smelt to spawn the next generation directly in the rivers so they can begin their lives in the watershed.

The scientists are hopeful, but Moyle says  it’s also “a desperation measure.” The factors that caused the wild smelt’s original decline have still not been properly addressed and the smelt are facing increasingly dire conditions. California and much of the U.S. West,  has also been in a drought since February 2020  and the beginning of 2022 continues to be historically dry.

One may wonder what hope there is, really, for such a little fish as the Delta smelt. Human combustion and emissions of fossil fuels continue to cause unprecedented warming around the world. And these hotter temperatures have also been noted to increase drought severity. So long as temperatures continue to rise as predicted, the Delta of today – plagued with unrelenting droughts and contested water projects and chemical runoff – will never be the Delta of the smelt’s past.

And eventually, without a proper habitat to enter into, those hatchery fish will have nowhere to go to.

Hanisha Harjani is a reporter, artist, and student, currently attending UC Berkeley Graduate School of Journalism.

Climate crisis forecasts a fragile future for wildflowers and pollinators

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A meadow of wildflowers, an important source of food for pollinating insects. Image by Ralphs_Fotos via Pixabay.
A meadow of wildflowers, an important source of food for pollinating insects. Image by Ralphs_Fotos via Pixabay.

By Spoorthy Raman, Mongabay (CC BY-ND 4.0).

  • A first-of-its-kind experimental study has found that climate change reduces the abundance of wildflowers and causes them to produce less nectar and fewer and lighter seeds.

  • These changes also impact pollinating insects visiting the flowers: they have to visit more flowers, more frequently, to gather the required food.

  • Fewer flowers imply reduced reproductive fitness in plants, as well as fewer food resources for invertebrates that rely on these plants for food, habitat and shelter.

  • Overall, climate change may disturb the composition of wildflower species and their pollinators, impacting agricultural crop yields, researchers say.

Think of climate change, and you’ll probably picture devastating floods, raging wildfires, or parched earth. For the environmentally savvy, coral bleaching or masses of refugees may also make it to the list. Not many of us would think of the vibrant wildflowers in nearby meadows as victims of climate change. But the future of these pretty blooms could be gloomy in the face of a warming planet, suggests a recent study published in the journal Frontiers in Plant Science.

This first-of-its-kind study, conducted in the U.K., found that wildflowers across Northern Europe would likely see a steep decline in abundance — up to 40%. In the experimental study, the researchers simulated the warmer, wetter conditions predicted for the region due to climate change. Under this new scenario, some species of plants produced flowers with 60% less nectar and fewer or lighter seeds. Due to these changes, pollinating insects had to visit more flowers to gather the needed pollen and nectar, and visited each flower more frequently.

“Our results demonstrate that climate warming could have severe consequences for some species of wildflowers and their pollinators in agricultural systems, and shows that their community composition is likely to change in the future,” said lead author Ellen D. Moss, a research associate at Newcastle University in the U.K.

While theoretical studies have predicted that climate change could accelerate pollinator losses and wildflower declines, Moss’s study marks the first time scientists have put the theory to the test in an experimental setting. And previous climate change studies have focused on a small number of either plants or pollinating insects in a particular region, and not looked at the effects at a community level.

“This study adds to the weight of evidence that pollinators are at risk from multiple stressors,” said ecologist Jane Stout from Trinity College Dublin, who was not involved in the study. “They are losing places to feed and breed, and they are stressed by pesticides, disease and changes in climate.”

To do this, the researchers sowed spring wheat and a few native wildflowers, which grow on wheat farms, in small agricultural plots in a North Yorkshire farm. They then heated some of these plots with infrared heaters to increase the soil temperature by 1.5° Celsius (2.7° Fahrenheit) and they increased the water supply by 40% to mimic the predicted wetter conditions from future climate change for Northern Europe. The non-heated plots acted as a control in their experiments to compare their results with.

For two flowering seasons, 2014 and 2015, the researchers tracked the different plant species that grew in these plots, the number of flowers they produced, the volume of nectar in them, and the weight of the dried seeds resulting from the flowers. They also collected information about visiting insect pollinators, including their visiting patterns to both the experimental and untouched plots.

The study reported 25 plant species and 80 insect species in 2014, and 19 plant and 69 insect species in 2015. Higher temperatures and more precipitation didn’t change what species were found in the plots, with the most abundant wildflowers being corn marigold (Glebionis segetum), cornflower (Centaurea cyanus), common field-speedwell (Veronica persica), shepherd’s purse (Capsella bursa-pastoris), chickweed (Stellaria media) and red dead-nettle (Lamium purpureum).

Hoping for orange cornflowers next year, or maybe blue poppies. Source: Terry Lucas, CC BY 3.0 via Wikimedia Commons
Hoping for orange cornflowers next year, or maybe blue poppies. Source: Terry Lucas, CC BY 3.0 via Wikimedia Commons.

Not only did wildlife abundance plunge by up to 40% in the heated plots, most of the plants in these plots also had fewer seeds in the seed heads, and the seeds weighed much less than those in non-heated plots. The only exception was the generalist weed known as common field-speedwell. While it produced more and heavier seeds in the heated plots, its flowers secreted 65% less nectar, making it a less popular flower with pollinators.

“A key finding [of the study] is that not all wild plant species respond to experimental manipulation in the same way, and so the implications for plant communities, and their interactions with pollinators, are complex to predict,” Stout said. Nevertheless, the general decrease in both the abundance and the number of seeds produced is of concern, she added, “because loss of floral resources in the landscape is already a major driver of pollinator decline.”

The study also found marked changes in the feeding behavior of pollinators in the heated plots. Hoverflies, honeybees and bumblebees, which were the most abundant insects, visited more flowers, and increased the frequency of their visits to the same flower to collect the nectar and pollen they needed.

“Fewer flowers and less nectar mean less food for pollinators,” Moss said, adding that such conditions may drive competition between pollinators and force them to choose less optimal flowers. “This could reduce their fitness and survival.”

Veronica persica (also known as field-speedwell) is a flowering plant in the plantain family Plantaginaceae. Source: AnRo0002, CC0, via Wikimedia Commons.
Veronica persica (also known as field-speedwell) is a flowering plant in the plantain family Plantaginaceae. Source: AnRo0002, CC0, via Wikimedia Commons.

A gloomy future for the blooms

Worldwide, two in five plants, including wildflowers, are threatened with extinction due to land use change for agriculture, housing and construction. In California, which is experiencing increasingly hotter and drier winters due to climate change, studies have recorded a decline of wildflower species by 15% in 15 years. In the U.K., human activities have destroyed about 97% of wildflower meadows since the 1930s, threatening once commonly seen plants like wild strawberry (Fragaria vesca), harebell (Campanula rotundifolia), and ragged robin (Silene flos-cuculi).

The loss of wildflowers also has a knock-on effect on thousands of insect species, including pollinators like bees and herbivores like aphids, grasshoppers and caterpillars. It also hits populations of natural pest controllers like spiders, ladybirds and lacewings that take shelter in the meadows. Studies show that, worldwide, a quarter of known bee species have not been seen since the 1990s, and loss of habitat is one of the primary reasons for the decline.

“[Climate change] risks crop pollination and our own food supply, but perhaps of more concern is the risk to wild plant pollination and our ecosystems and all the other benefits we get from them,” Stout said.

Tackling climate change by rapidly decreasing emissions would save at least some of the blooms, but in the meantime, there are other steps that could prevent a catastrophic future for wildflowers.

“The main things that will improve ecosystem resilience in the context of wildflowers and pollinators is to improve habitat quantity, quality and connectivity,” Moss said. “We need to leave more wild spaces for native plants and insects and try to connect these areas up so that these patches of high-quality habitat are not too small or too far apart.”

Citations:

Moss, E. D., & Evans, D. M. (2022). Experimental climate warming reduces floral resources and alters insect visitation and wildflower seed set in a cereal agro-ecosystem. Frontiers in Plant Science. doi:10.3389/fpls.2022.826205

(2020). State of the World’s Plants and Fungi 2020. Royal Botanic Gardens, Kew. doi:10.34885/172

Harrison, S. P., Gornish, E. S., & Copeland, S. (2015). Climate-driven diversity loss in a grassland community. Proceedings of the National Academy of Sciences, 112(28), 8672-8677. doi:10.1073/pnas.1502074112

Zattara, E. E., & Aizen, M. A. (2021). Worldwide occurrence records suggest a global decline in bee species richness. One Earth, 4(1), 114-123. doi:10.1016/j.oneear.2020.12.005

Natural Resources Necessary to Feed World Are at a ‘Breaking Point,’ Warns FAO

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Photo by Tim Mossholder on Unsplash
Photo by Tim Mossholder on Unsplash

“Taking care of land, water, and particularly the long-term health of soils is fundamental to accessing food in an ever-demanding food chain.”

By Jessica Corbett, Common Dreams (CC BY-NC-ND 3.0).

A United Nations report released Thursday detailing humanity’s degradation of natural resources warns swift and sweeping reforms are needed to keep feeding the growing global population.

“The pressures on land and water ecosystems are now intense, and many are stressed to a critical point.”

The new U.N. Food and Agriculture Organization (FAO) report argues that “a sense of urgency needs to prevail over a hitherto neglected area of public policy and human welfare, that of caring for the long-term future of land, soil, and water.”

“Taking care of land, water, and particularly the long-term health of soils,” the publication explains, “is fundamental to accessing food in an ever-demanding food chain, guaranteeing nature-positive production, advancing equitable livelihoods, and building resilience to shocks and stresses arising from natural disasters and pandemics.”

Entitled The State of the World’s Land and Water Resources for Food and Agriculture: Systems at breaking point (SOLAW 2021), the report declares that “time is of the essence.”

That tone is echoed by FAO Director-General Qu Dongyu in a foreword to the report, which he says provides “evidence of the changing and alarming trends in resource use.”

“The pressures on land and water ecosystems are now intense, and many are stressed to a critical point,” Qu writes. “It is clear our future food security will depend on safeguarding our land, soil, and water resources.”

Already, human-induced soil degradation affects 34% of land used for food while water scarcity threatens 3.2 billion people—nearly half the total human population—in agricultural areas, according to SOLAW 2021.

Alongside its broad warning that “the interconnected systems of land, soil, and water are stretched to the limit,” the report emphasizes that “current patterns of agricultural intensification are not proving sustainable,” and “farming systems are becoming polarized,” with an “increasing concentration of land under a relatively small number of large commercial farming enterprises.”

Recognizing the need to better manage and safeguard land and water resources essential for food production, the report offers four key takeaways:

  • Land and water governance has to be more inclusive and adaptive;
  • Integrated solutions need to be planned at all levels if they are to be taken to scale;
  • Technical and managerial innovation can be targeted to address priorities and accelerate transformation; and
  • Agricultural support and investment can be redirected towards social and environmental gains derived from land and water management.

“Current patterns of agrifood production are not proving sustainable,” Qu said Thursday at the report’s launch event. “Yet, agrifood systems can play a major role in alleviating these pressures and contributing positively to climate and development goals.”

In his foreword, Qu notes that “a meaningful engagement with the key stakeholders—farmers, pastoralists, foresters, and smallholders—directly involved in managing soils and conserving water in agricultural landscapes is central.”

“These are nature’s stewards and the best agents of change to adopt, adapt, and embrace the innovation we need to secure a sustainable future,” he adds.

Some of those same stakeholders have been critical of the U.N. agency in recent months.

A coalition of food justice advocates last week sent a letter to Qu calling on the FAO to cut ties with CropLife International, warning that any collaboration with the agrochemical trade association “undercuts your agency’s critical—and urgently needed—support for agroecology, which FAO itself notes ‘can support food production and food security and nutrition while restoring the ecosystem services and biodiversity that are essential for sustainable agriculture.'”

Earlier this year, the FAO leader’s remarks at the U.N. Food Systems Summit were among those flagged by justice campaigners as evidence that the September event was “paving the way for greater control of big corporations over global food systems and misleading the people through corporate-led false solutions.”

Just before the summit, during a counter-mobilization, Razan Zuayter of the People’s Coalition on Food Sovereignty had said that “food systems can be transformed through the respect of food sovereignty via the will of landless peasants, small farmers, and fishers.”

“We have shown that the people are hungry for real change,” Zuayter added, “and are willing to do whatever it takes to fight for and reclaim their land, their rights, and the future of food systems.”