In science news this week, New research paper on the impact of surface water diversions for marijuana cultivation on aquatic habitat in four Northwestern California watersheds, Central Valley, 2100: Land Use and Climate Change Could Impact Wildlife & Water Supplies, FishBio blog on the disappearing salmon carcass, 18 months after the fire on Mt. Diablo, Rethinking wetland restoration, and more …
Research paper: The impact of surface water diversions for marijuana cultivation on aquatic habitat in four Northwestern California watersheds: ABSTRACT: “Marijuana (Cannabis sativa L.) cultivation has proliferated in northwestern California since at least the mid-1990s. The environmental impacts associated with marijuana cultivation appear substantial, yet have been difficult to quantify, in part because cultivation is clandestine and often occurs on private property. To evaluate the impacts of water diversions at a watershed scale, we interpreted high-resolution aerial imagery to estimate the number of marijuana plants being cultivated in four watersheds in northwestern California, USA. Low-altitude aircraft flights and search warrants executed with law enforcement at cultivation sites in the region helped to validate assumptions used in aerial imagery interpretation. We estimated the water demand of marijuana irrigation and the potential effects water diversions could have on stream flow in the study watersheds. Our results indicate that water demand for marijuana cultivation has the potential to divert substantial portions of streamflow in the study watersheds, with an estimated flow reduction of up to 23% of the annual seven-day low flow in the least impacted of the study watersheds. Estimates from the other study watersheds indicate that water demand for marijuana cultivation exceeds streamflow during the low-flow period. In the most impacted study watersheds, diminished streamflow is likely to have lethal or sub-lethal effects on state-and federally-listed salmon and steelhead trout and to cause further decline of sensitive amphibian species.” Read the paper here: The impact of surface water diversions for marijuana cultivation on aquatic habitat in four Northwestern California watersheds
Central Valley: Home on the range, Year 2100: Land Use and Climate Change Could Impact Wildlife, Water Supplies: “Grassland habitats on rangelands in California’s Central Valley and surrounding foothills could decline by as much as 37 percent by 2100 due to changes in land use and climate, according to new scientific projections by the U.S. Geological Survey. The peer reviewed, scientific paper was published recently in the journal Landscape Ecology. In addition to habitat loss, the study shows that increased development of rangelands for urban use exacerbates the ongoing issues surrounding rainwater runoff. When this issue is combined with periods of drought, the area will suffer from reduced the opportunities for groundwater recharge, especially on deep soils. “Results from this study reinforce the role of open rangelands in capturing water and reducing runoff,” said Dr. Kristin Byrd, the study’s lead author and a physical scientist with the USGS. “Maintaining rangelands can help mitigate the effects of climate change and drought.” ... ” Read more from the USGS here: Home on the range, Year 2100: Land Use and Climate Change Could Impact Wildlife, Water Supplies
FishBio blog on the disappearing salmon carcass: “When we attempt to document natural processes in the field through photo or video, we sometimes run into challenges when nature gets other ideas. During the Chinook salmon spawning season last fall, we set up a GoPro camera on a tripod hidden on private property in an attempt to capture a decaying carcass as it decomposed over the course of a few weeks. While things didn’t go quite according to our plans, the result was still interesting. The first carcass we chose was carried off by scavengers in just a few days, so we tried again, this time staking the fish to the ground. … ” Continue reading at the FishBio blog here: The disappearing salmon carcass
Second spring: 18 months after the fire on Mt. Diablo: “Last spring was a banner year on Mount Diablo. The extra nutrients, space, and sunlight provided by a 3,100-acre fire made this wildflower mecca better than ever. Rare plants such as the Mount Diablo jewelflower were easier to find. Fields of lilies, poppies, and morning glories popped up in profusion. One of several fire-following plants that many visitors had never seen before, whispering bells, carpeted whole hillsides with its delicate yellow blossoms. “It was the best year for wildflowers that many of us have ever seen on Mount Diablo,” said longtime Save Mount Diablo staffer Seth Adams. “A once-in-a-generation experience.” ... ” Read more from Bay Nature here: Second spring
Rethinking wetland restoration: Smaller wetlands more valuable than previously thought: “Most efforts to protect and restore wetlands mistakenly focus on preserving only total wetland area, with no consideration of ecosystem services provided by different wetland types, according to a new study from the University of Waterloo. The study, published in the peer-reviewed journal Ecological Applications last month, shows wetland loss follows a strong pattern, with smaller, isolated wetlands being lost in much greater numbers than larger wetlands. … ” Read more from Science Daily here: Rethinking wetland restoration: Smaller wetlands more valuable than previously thought
Western forests decimated by pine beetles not more likely to burn: “Western U.S. forests killed by the mountain pine beetle epidemic are no more at risk to burn than healthy Western forests, according to new findings by the University of Colorado Boulder that fly in the face of both public perception and policy. The CU-Boulder study authors looked at the three peak years of Western wildfires since 2002, using maps produced by federal land management agencies. The researchers superimposed maps of areas burned in the West in 2006, 2007 and 2012 on maps of areas identified as infested by mountain pine beetles. … ” Read more from Science Daily here: Western forests decimated by pine beetles not more likely to burn
Traces left behind: “Humans shed tens of thousands of skin cells every hour, leaving behind traces of their presence everywhere they go. Contained in each of these cells is an individual’s entire set of DNA, or even multiple copies of it (in the case of mitochondrial DNA). Fish and other organisms are no different, and scientists have begun to explore ways to sample the environment to find these often elusive clues of a species’ presence in the form of “environmental DNA,” or “eDNA.” There are numerous pathways for cells and genetic material to enter the environment as eDNA, including natural sloughing of skin, intestinal lining excreted with feces, tissue separated from the body by injury, cells released into the water during reproduction, decomposition of dead organisms, and even in waste from predatory species if an organism was consumed. As long as the DNA contained in these cells persists in the environment, scientists have an opportunity to detect the genetic signature unique to each species. … ” Read more from the FishBio blog here: Traces left behind
Shrinking habitats have adverse effects on world ecosystems: “An extensive study of global habitat fragmentation — the division of habitats into smaller and more isolated patches — points to major trouble for a number of the world’s ecosystems and the plants and animals living in them. The study shows that 70 percent of existing forest lands are within a half-mile of the forest edge, where encroaching urban, suburban or agricultural influences can cause any number of harmful effects — like the losses of plants and animals. … ” Read more from Science Daily here: Shrinking habitats have adverse effects on world ecosystems
Plants’ defensive responses have downstream effects on nearby ecosystems: “Chemical changes that occur in tree leaves after being attacked by insects and mammals can impact nearby streams, which rely on fallen plant material as a food source, report scientists from the University of Chicago Department of Ecology and Evolution. The study, published March 17 in the journal Proceedings of the Royal Society B, shows how interactions between terrestrial and aquatic ecosystems are an essential part of understanding ecological responses to climate change. Graduate student Sara Jackrel and Timothy Wootton, PhD, professor in the Department of Ecology and Evolution, simulated herbivory, or the activity of insects eating leaves, on red alder trees in a forest on the Olympic Peninsula in Washington state. Their research showed caterpillars ate fewer leaves from the stressed trees than those that were left alone. Leaves from these stressed trees also decomposed much more slowly when submerged in nearby streams, and further results suggest that the trees funneled a valuable nutritional resource away from the leaves as a defensive response to animal attacks. ... ” Read more from Science Daily here: Plants’ defensive responses have downstream effects on nearby ecosystems
Global water use may outstrip supply by mid-century: “Population growth could cause global demand for water to outpace supply by mid-century if current levels of consumption continue. But it wouldn’t be the first time this has happened, a Duke University study finds. Using a delayed-feedback mathematical model that analyzes historic data to help project future trends, the researchers identified a regularly recurring pattern of global water use in recent centuries. Periods of increased demand for water — often coinciding with population growth or other major demographic and social changes — were followed by periods of rapid innovation of new water technologies that helped end or ease any shortages. Based on this recurring pattern, the model predicts a similar period of innovation could occur in coming decades. ... ” Read more from Science Daily here: Global water use may outstrip supply by mid-century
The stepping stones of integrating emotions into practicing science: “I was a scientist just a few years out of graduate school when I had a career-altering experience speaking with a man in tears at a community workshop. A large cluster of wildfires had burned through his small, close-knit northern California town, and many residents were forced to evacuate their homes. They were worried that their properties would be unprotected in the time they had to stay away: firefighting resources were strained due to additional wildfires in other parts of the state. Emotions ran high for everyone as my colleagues and I presented our work on how houses burn during wildfires. … ” Read more from On Being here: The stepping stones of integrating emotions into practicing science
Maven’s XKCD Comic Pick of the Week …
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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.