SCIENCE NEWS: Dealing with aquatic weeds, Drought and salmon, Drawing boundaries with DNA, Unifying sediment transport, Water cycle modifications, and more …

Please leaf: We need new ways to control aquatic weeds:  “Weeds may be annoying to gardners, but they can prove devastating for ecosystems once they escape into the environment, leaving no space for native plants and animals. This is the case in the Sacramento-San Joaquin Delta, where non-natives represent half of the plant species and make up most of the aquatic plant cover. Despite control efforts, the problem has continued to grow. New and innovative solutions are needed to address this challenge, and a recent report from the Delta Stewardship Council provides recommendations on how to deal with the expensive and ecologically destructive issue (Conrad et al. 2020). With thousands of acres of planned restoration sites threatened by the spread of aquatic weeds, there’s no time to waste. … ”  Read more from FishBio here: Please leaf: We need new ways to control aquatic weeds

Spring-run Chinook salmon – essential to life history diversity:  “In northern California, springtime is marked by wildflower blooms, bird migrations, swollen rivers, and the return of the first salmon of the year to the Klamath River – spring-run Chinook salmon.  This genetically-based life history strategy of Chinook salmon is not only critical to the genetic diversity of the species and the economy for fishing, but also provides a vital source of food and other cultural value for indigenous people of the Klamath Basin.  “You can ask any tribal member right now, and they will tell you that one spring salmon is worth 8-10 fall fish. They are that valuable. If I had two jars sitting here, you could see on the spring fish an inch of red oil and the fall fish sitting right next to it with almost no red ring,” said Keith Parker, a Yurok tribal member and biologist referring to the fat content. … ”  Read more from the US FWS here:  The natural portfolio:  Spring-run Chinook salmon – essential to life history diversity

What does drought mean for endangered California salmon?  “Increased frequency and severity of droughts threatens California’s endangered salmon population — but pools that serve as drought refuges could make the difference between life and death for these vulnerable fish, according to a study by researchers from UC Berkeley and California Sea Grant, a partnership between NOAA and Scripps Institution of Oceanography at the University of California San Diego. The research could help resource managers strategically protect and restore salmon habitat.  The new study, published in the journal Global Change Biology, tracked nearly 20,000 tagged fish in Sonoma County streams over a seven-year period from 2011 to 2017. The Russian River watershed is home to a highly endangered population of coho salmon, which nearly collapsed in the early 2000’s, but has been recovering since then through a conservation hatchery program and other efforts. … ”  Read more from California Sea Grant here:  What does drought mean for endangered California salmon?

DWR completes juvenile salmon habitat study amid COVID-19 emergency:  “A study by the Department of Water Resources (DWR) investigating the growth rate of juvenile Chinook salmon raised in the Suisun Marsh area of Solano County was forced to conclude early due to the ongoing COVID-19 health emergency. Despite the change of plans, DWR scientists were still able to gather all pertinent data and are confident the study will provide useful information regarding how juvenile Chinook salmon grow.  “Originally the study was going to last eight or nine weeks,” said Brett Harvey, senior environmental scientist with DWR’s Division of Environmental Services (DES). “Two weeks into the 2020 study period COVID-19 protocols and guidelines went into effect and threw a real wrench in our plans.” … ”  Read more from DWR News here: DWR completes juvenile salmon habitat study amid COVID-19 emergency

DWR enters ‘whale’s belly’ to combat climate change, protect water deliveries:  “A marshy tract known as Sherman Island is one of the most sensitive and geographically important locations for water conveyance in California. On May 11, DWR began a restoration project on the southeast side of the island that combats climate change while protecting statewide water supply.  The 10,000-acre Sherman Island, which sits at the confluence of the Sacramento and San Joaquin rivers between the cities of Rio Vista and Antioch, has sunk up to 20-feet below sea level since the Gold Rush due to evaporating peat soils. This sinking of land – a process known as subsidence –strains levees that protect Sherman and nearby Delta islands. ... ”  Read more from DWR News here:  DWR enters ‘whale’s belly’ to combat climate change, protect water deliveries

Drawing boundaries with DNA to improve conservation:  “Foothill Yellow-legged Frogs have begun to spawn, laying small snow-globe sized egg masses in streams and rivers. They are one of the few stream-breeding frogs endemic to California and Oregon. This species is a good indicator of stream health because they link aquatic and terrestrial ecosystems and are strongly tied to natural seasonal cues associated with local hydrology. Historically, they occurred in streams and rivers throughout California and Oregon, but, as with many amphibians, they have precipitously declined in many parts of their range due to river regulation, habitat loss, and disease. ... ”  Read more from the California Water Blog here: Drawing boundaries with DNA to improve conservation

From blowing wind to running water: unifying sediment transport:  “Geomorphologists seek to understand why natural landscapes look the way they do. Key to this is understanding sediment transport, especially the thresholds at which sediments start and stop moving, and the rate at which sediments move around in different conditions. A recent article in Reviews of Geophysics presented an overview of the physics of sediment moved by wind and water. Here, the authors give an overview of advances in our understanding of sediment transport.  ... ”  Read more from EOS here:  From blowing wind to running water: unifying sediment transport

Rising Seas: EROS brings valuable elevation knowledge to islands, coastlines:  “As sea levels rise around the planet, as storm surges threaten islands and coastal communities, decision makers face a lot of questions about how to protect their citizens and their landscapes.  Staff at the U.S. Geological Survey’s (USGS) Earth Resources Observation and Science (EROS) Center can provide them some important answers.  Understanding the impacts of rising sea levels requires accurate elevation information both beneath the water near shore, and along nearby coastal landscapes. Few agencies provide that broad-scale, regional elevation data as accurately as EROS does.  Research Physical Scientist Dean Gesch, the principal investigator for the Coastal Changes and Impacts focus area within the Integrated Science and Applications Branch (ISAB) at EROS, talks about his agency’s elevation expertise, and about sea level rise, in this conversation. … ”  Read more from the USGS here: Rising Seas: EROS brings valuable elevation knowledge to islands, coastlines

Shrub encroachment on grasslands can increase groundwater recharge:  “Grasslands across the globe, which support the majority of the world’s grazing animals, have been transitioning to shrublands in a process that scientists call “woody plant encroachment.”  Managed grazing of drylands is the most extensive form of land use on the planet, which has led to widespread efforts to reverse this trend and restore grass cover due to the belief that it results in less water entering streams and groundwater aquifers.   A new study led by Adam Schreiner-McGraw, a postdoctoral hydrology researcher at the University of California, Riverside, modeled shrub encroachment on a sloping landscape and reached a startling conclusion: Shrub encroachment on slopes can increase the amount of water that goes into groundwater storage. The effect of shrubs is so powerful that it even counterbalances the lower annual rainfall amounts expected during climate change.  … ”  Read more from UC Riverside here:  Shrub encroachment on grasslands can increase groundwater recharge

Increased frequency of connected patterns from drought to heavy rain in regional hotspots:  “Like an undulating seesaw, weather in some regions swings from drought to heavy rain under the weight of climate-induced changes, according to an analysis published in Geophysical Research Letters. The study finds a link between droughts followed by heavy rain events, along with an increased rate of these extreme weather occurrences.  In areas with vulnerable populations and high poverty rates, these swings are likely to exacerbate conditions. This research could inform more effective climate adaptation planning and policies by identifying where these swings are likely to occur. … ”  Read more from Phys Org here:  Increased frequency of connected patterns from drought to heavy rain in regional hotspots

How much modification can earth’s water cycle handle?  “Earth’s fresh water is essential: It helps regulate climate, support ecosystems, and sustain human activities. Despite its importance to the planet, humans are modifying fresh water at an unprecedented scale, and by damming rivers, pumping groundwater, and removing forests, humans represent the primary source of disturbances in the world’s freshwater cycle.  Extensive modifications to the water cycle and perturbations to other Earth processes prompted the development of the planetary boundaries framework roughly a decade ago. The framework defines the “safe operating space” for essential Earth system processes, including fresh water, and sets limits beyond which we risk rapidly and maybe irreversibly disrupting critical global systems. ... ”  Read more from EOS here: How much modification can earth’s water cycle handle?

Featured Image: “Wondrous wetlands” by USGS

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About Science News and Reports: This weekly feature, posted every Thursday, is a collection of the latest scientific research and reports with a focus on relevant issues to the Delta and to California water, although other issues such as climate change are sometimes included. Do you have an item to be included here? Submissions of relevant research and other materials is welcome. Email Maven

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