Recent accomplishments of CDFW's scientific community
CDFW wants to know if, when and where you’ve seen an elk in California – and they’ve just created a new online reporting tool that makes it easy for members of the public to share this information.
CDFW scientists will use the raw data to help guide their efforts to study statewide elk distribution, migration patterns and herd movement, population size estimates, habitat use, health and diseases, and causes of mortality.
“We have limited resources and our scientists cannot scan the entire landscape,” explained CDFW Senior Environmental Scientist Pete Figura. “This tool provides a way for us to leverage the many sightings of the wildlife-watching public. People often get excited when they see elk, and hopefully now they will channel that excitement by reporting the location and time of their sighting to our department.”
There are three subspecies of elk in the state – tule, Rocky Mountain and Roosevelt -- and all three have expanded their range in recent years according to Figura.
CDFW has elk studies underway in the northern part of the state: one is focused on Roosevelt elk in Humboldt and Del Norte counties, and the other is focused on elk in Siskiyou and Modoc counties. Tracking and studying such a large mammal is a complex undertaking as elk herds are wide-ranging, and often graze and browse in areas that are not easily accessible, and there are only so many scientists to monitor their movements.
The launch of the reporting tool is just the latest effort to enhance the management of elk in California. Last year CDFW released a public draft of the Statewide Elk Conservation and Management Plan that addresses historical and current geographic range, habitat conditions and trends, and major factors affecting elk in California.
The plan will provide guidance and direction for setting priorities for elk management efforts statewide. CDFW is reviewing public comments on the plan and will incorporate appropriate changes into the final document prior to its release, which is expected soon.
CDFW Wildlife Branch Chief Kari Lewis has termed the plan an “important milestone” and explained that public feedback is a critical part of shaping the effort, which emphasizes a sharing of resources and collaboration with all parties interested in elk and elk management. This, she said, is essential to effectively managing California’s elk populations.
For more information about elk in California, please visit CDFW’s elk management webpage.
CDFW File Photo. Top photo: Group of Tule Elk.
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The California Department of Fish and Wildlife (CDFW) recently launched the first phase of a multi-year study of tule elk in Colusa and Lake counties. In partnership with the University of California, Davis and the Rocky Mountain Elk Foundation, and with the assistance of capture specialists from Leading Edge Aviation, researchers used helicopter net guns to capture and place satellite collars on 45 tule elk.
The technique of using DNA extracted from fecal pellets to study wildlife populations is a relatively new, non-invasive approach that minimally disturbs animals and enables surveys in low-visibility habitats where sight-based surveys would be relatively ineffective. It is also less costly than other survey methods, and therefore can be used more frequently.
While fecal DNA analysis has been used to estimate abundance and other population parameters in deer herds in California since 2011, this study will be the first application of the technique to free-ranging tule elk. The study results will guide future elk conservation planning efforts.
Tule elk are a native subspecies of elk unique to California. Prior to the arrival of European settlers, they numbered more than half a million statewide, but the population rapidly declined in the mid-1800s due to unregulated market hunting and habitat loss. In 1875, a ranch owner in Kern County took efforts to protect the last remaining tule elk and allowed them to multiply on his property, likely saving them from extirpation.
Since 1975, CDFW has captured and relocated more than 1,500 elk. As a result, there are an estimated 5,100-plus tule elk distributed in 22 herds throughout California today. See more information about the distribution, range and history of this unique animal in California.
Porcupine1: NRVP participants Greg Moore, Mike Maulhardt, Charles Brown and Ben Smith volunteered to service and maintain porcupine stations at Red Lake Wildlife Area.
Not to put too fine a point on it, but studying California’s porcupines hasn’t traditionally been a high priority for CDFW.
Wildlife research funding is limited, especially for non-game species, and species listed as threatened or endangered are typically given top priority. That means that scientists sometimes need to be creative – and frugal – in their efforts to survey and manage non-listed, non-game species.
Stacy Anderson, a CDFW senior environmental scientist specialist based in Rancho Cordova, recently conducted a pilot project that does just that.
Anderson developed an interest in the North American porcupine (Erethizon dorsatum) in 2017, after acknowledging that anecdotal evidence seems to indicate their numbers are on the decline.
Porcupines have historically inhabited diverse habitats including Humboldt County, along the Sacramento River, in the Coast Ranges, the Klamath Mountains, the southern Cascades, the Modoc Plateau and the Sierra Nevada. But in her conversations with unit biologists and wildlife officers in some of these areas, Anderson took note that many were reporting a substantial decrease in the number of calls from residents whose property – typically wood structures such as decks and outhouses – had been damaged by porcupines in recent decades. Informal surveys of veterinarians across the state also indicated a decline in the number of pet owners seeking quill removal from their pets.
Perhaps most telling, CDFW’s Sierra Nevada monitoring project, which has studied portions of the Sierra for the past nine years, has documented only seven porcupine sightings out of 750 stations surveyed via trail camera.
“We are worried about them because we don’t have a lot of sightings,” Anderson said. They live in low densities and they have only have one baby per year, so they don’t repopulate quickly.”
Recognizing the need to gather more information, Anderson and Evan King, another CDFW environmental scientist, launched a pilot effort last year to improve surveillance of porcupine, with a long-term goal of determining distribution and population numbers.
Anderson and King were inspired by the work of Uldis Roze, a researcher who has long studied porcupines in the Catskills of New York by using wood soaked in salt brine as a porcupine attractant. His research indicates that porcupines show a strong seasonality of salt use, which peaks in April through May and August through September. Because porcupines’ diet of plant matter is generally low in sodium (salt), they seek out other dietary sources of sodium to maintain normal levels in their bodies.
Anderson and King theorized that brined wood could be effective in attracting California porcupines, too. A plan was made to soak stakes made from 2x2s in a sodium brine to monitor activity. In theory, tooth scrapings on the wood could also be identified to species.
“It’s not a full-blown study – it’s just a way to test a plan of action that can maybe be used in a study later,” Anderson explained. “We don’t want to waste valuable resources on untested methodology, so this is a way to find out first if the methodology is going to work. It’s a low-cost, high yield approach.”
Twenty-three stations were set up for the 2017 pilot project, which was conducted from April to October. Members of CDFW’s Natural Resources Volunteer Program, who support departmental operations, supplied much of the labor, and the study costs were kept low. Expenses added up to less than $100, including salt for brining and wood. Trail cameras borrowed from other researchers were utilized to help monitor the stations.
Researchers were pleased to learn that the porcupines took to their efforts with a grain of salt (so to speak). They determined that brined-wood monitoring is more effective than traditional bait or game-trail monitoring, at least in the study area in northern Sierra and along the Sacramento River. Preliminary results indicate that the brined wood appeared to lure porcupines into the area of a camera station -- although most did not approach the wood and fewer still left a distinctive chew mark on the brined wood. But the trail cameras provided clear, useful photographs.
“We still have unanswered questions about this technique that will need to be addressed before we can consider it a success,” Anderson said. “However, our pilot efforts are promising.”
CDFW is seeking additional funding through state wildlife grants and collaborative efforts with other researchers and agencies to gain a better understanding of the North American porcupine’s status. Anderson plans to continue refining the methodology of her study, along with other survey techniques including habitat surveys, feeding signs, tree girdling, scat searches and the use of detection dogs.
Anderson also encourages members of the public to help CDFW’s efforts by reporting detections of live or “roadkill” porcupines.
CDFW Photos. Top Photo: Porcupine photo by CDFW Warden Chad Alexander.
Scientists with the California Department of Fish and Wildlife (CDFW) and Oregon State University recently published the results of a population study on fishers (Pekania pennanti) in northern California and southern Oregon. Led by CDFW Wildlife Statistician Dr. Brett Furnas and three coauthors, CDFW Senior Environmental Scientist Richard Callas, CDFW Research Analyst Russ Landers and Dr. Sean Matthews of Oregon State University, the study produced the first-ever robust estimates of density and size of the fisher population in northern California.
“This is the first time we’ve come up with a solid number of fishers, which is a starting point for tracking and monitoring populations,” Furnas said. “One of the most important tools we have used so far to help this species is reintroductions, so now -- with a baseline established and ongoing surveys planned -- we’ll be able to see if the population is really rebounding over time.”
Fishers in northern California and southern Oregon represent the largest remaining population in the Pacific states. The species once ranged from the state of Washington southward through Oregon and California. Currently, fishers occupy only a small portion of their historical range in that region. In California, fishers are found in the northern areas of the state and a small, isolated population occurs in the southern Sierra Nevada Mountains.
CDFW and the U.S. Fish and Wildlife Service have been petitioned on several occasions to list fishers as threatened or endangered under their respective Endangered Species Acts.
In 2016, while considering fishers in the southern Sierra Nevada Mountains of California, the California Fish and Game Commission voted that the petitioned action was warranted in part, choosing to accept the petition in the context of the Southern Sierra Nevada Evolutionarily Significant Unit, and adopted findings to that effect, which were published on May 6, 2016. Although fishers are relatively well-distributed in northern California and in portions of southern Oregon, data from existing surveys and prior studies was used to estimate abundance. This information is critically important to assess the status of fishers and serve as a baseline for conservation efforts.
Furnas and his coauthors used data from camera traps, hierarchical modeling of detections and non-detections of fishers from the cameras, and information about fisher home range size to develop their estimate of population size. They estimated that approximately 3,200 fishers occur within the northern California and southern Oregon study area, with an average density of 5.1 to 8.6 fishers per 100 square kilometers.
Estimating the sizes of wildlife populations is challenging, particularly for species such as the fisher that are difficult to observe and occur over large areas. A final population estimate for the fisher would not have been possible without the cooperation of a variety of federal and tribal agencies, universities and private landowners who shared datasets that were combined to complete the modeling. With these data, Furnas and his coauthors demonstrated that estimating the population size of the fisher at large geographic scales is feasible. They also suggested that the methods used in their research could be used to estimate the abundance of other carnivores, including black bear, gray fox and coyote.
The study was published in the journal Ecosphere. More information / view publication
It does not take a leap of faith to believe that CDFW scientists have gained the upper hand in bolstering the population of yellow-legged frogs in the High Sierra.
Over the past three decades, Sierra Nevada yellow-legged frogs have become imperiled in California due to the two-pronged impact of introduced (non-native) trout and chytridiomycosis, a disease that is affecting amphibians worldwide.
Past introduction of non-native fish, including rainbow trout and golden trout, to benefit sport fishing in the High Sierra took a heavy toll on the species. High-elevation lakes where these frogs once flourished were largely fishless until fish stocking came into vogue. As the years passed, scientists determined that these introduced fish were depopulating the frogs by competing for food sources (primarily insects) and by predation (trout ate both adult frogs and their tadpoles). Chytridiomycosis, which affects many frog species, also impaired the ability of the Sierra Nevada yellow-legged frog’s skin to exchange vital nutrients, which often leads to death.
As a result, Sierra Nevada yellow-legged frogs are believed to have vanished from approximately 92 percent of their historical habitat, and halting and reversing that decline has become an important goal of CDFW, as well as other state and federal entities.
“This is an animal that only lives in the Sierra Nevada,” said Sarah Mussulman, a CDFW senior environmental scientist. “It is one of our unique California species that lives in high-elevation areas, and as an amphibian it serves as an important link between the terrestrial and aquatic ecosystems. This link is especially critical in the low nutrient, granitic basins of the High Sierra, where frogs and tadpoles consume insects and algae and are themselves consumed by a variety of snakes, birds and mammals.”
CDFW recently completed two projects as part of its ongoing efforts to reverse the population decline of Sierra Nevada yellow-legged frogs.
The efforts took place at two sites: Highland Lake and Clyde Lake, located approximately seven miles apart on the Rubicon River in the Desolation Wilderness area of El Dorado County. The projects were completed with federal grant funds earmarked for the recovery of endangered and threatened species (the species is listed as threatened by the State of California and as endangered by the U.S. Fish and Wildlife Service).
Highland Lake, along with its outlet, an unnamed stream, and two small adjacent ponds, supported a small population of rainbow trout when the project began in 2012. Trout abundance had declined in the absence of stocking in recent years but sufficient natural reproduction occurred in the inlet to Highland Lake to sustain the population. CDFW began using gill nets to remove rainbow trout -- the descendants of fish planted in the lake by CDFW from 1935 to 2000 -- in 2012, in partnership with Eldorado National Forest personnel.
During a frog-monitoring survey at Highland Lake in 2016, approximately 800 adult frogs were observed, as compared to a 2003 survey in which only a few tadpoles were observed. Because the frogs have consistently survived in this area despite the presence of chytridiomycosis, scientists believe they have a good chance at persisting in the area for a long time.
“Highland really had a population explosion over the past five years and can be counted as one of the most successful projects of this type ever undertaken,” Mussulman said.
The project at Clyde Lake was smaller and had somewhat different factors.
Golden trout, which frequently have the same negative impacts on Sierra Nevada yellow-legged frogs as rainbow trout, including predation and competition for food sources, were planted by CDFW at Clyde Lake from 1932 through 2000.
Once stocking was halted, the golden trout proved less resilient then the rainbow trout at Highland Lake, due to habitat factors.
“Clyde Lake sits in a north-facing granite bowl bordered by 1,000-foot cliffs, and no flowing streams enter the lake,” explained Mussulman. “There was no spawning habitat, which is likely why golden trout did not persist there after stocking was halted.”
The stream flowing out of Clyde Lake and four nearby ponds did support a small population of golden trout after plants were halted. The fish in the stream and ponds, which are self-sustaining populations, are precluded from moving from the stream into Clyde Lake by a fabricated dam. In 2013, frogs and a few tadpoles were observed in the stream alongside fish, and CDFW began removing the fish from the stream with gill nets to provide additional habitat for the frogs.
Nine years of monitoring data collected by CDFW scientists indicate that the area’s Sierra Nevada yellow-legged frog population, while small, is slowly increasing. Surveyors observed more than 120 frogs in 2016, compared to a low of six observed in 2005. Moreover, in 2016, for the first time, dozens of tadpoles were observed in the newly fish-free lower reaches of the stream.
“It is great to see these populations recovering,” Mussulman said. “It is a great privilege doing this work that helps keep these frogs on the landscape.”
CDFW photos: Highland Lake in the Desolation Wilderness, and a Sierra Nevada yellow-legged frog
Beneath the waters off the California coast are vast forests that are home to an astounding variety of animals. Their sunlit canopies can soar 150 feet from the ocean’s floor. But instead of trees, these forests are made of kelp.
Worldwide, kelp is used in a host of everyday products like toothpaste, pudding, ice cream and even pharmaceuticals. Although kelp is valuable to humans, it is critical to sustaining life for many ocean-dwelling wildlife species ranging from microscopic plankton to sea otters, pelagic birds and predatory fishes. When a kelp forest is depleted, the entire underwater ecosystem can be thrown out of balance. This is why CDFW scientists are tracking and studying the amount of kelp growing in coastal waters.
In 1989, CDFW marine biologists began using aerial surveys to monitor the size of the kelp forests off of California’s coast. A second survey was conducted a decade later, and since 2002, CDFW has made an effort to conduct these surveys annually (although budget issues sometimes require skipping a year).
The surveys are conducted along the entire coastline and offshore of the Channel Islands. CDFW conducted the earliest surveys on its own, but now contracts out for this work. The contractor uses an aircraft with a specialized camera system that picks up the infrared image of the kelp. Those images become Geographic Information System (GIS) shapefiles that capture a snapshot of what the kelp canopy looks like on a given day. The images enable the viewer to see and compare the spatial area of a specific kelp forest over time.
A graph depicting CDFW’s historic aerial kelp survey data is located on the Kelp and Other Marine Algae webpage.
CDFW’s most recent (2016) kelp survey includes the following findings:
Rebecca Flores Miller, a marine environmental scientist with CDFW’s Marine Region office in Monterey, was the coordinator for the 2016 kelp survey.
“Kelp does fluctuate normally, anyway … there is a seasonality with it,” she explains. “However, during El Nino and warm water conditions as we’ve had in the recent past, the canopy doesn’t grow as well.”
Coastal development can also negatively affect the kelp canopy, as it sometimes leads to pollution, increased turbidity (which reduces the light needed for photosynthesis) and siltation (which can hinder growth or bury young kelp). An increase in urchin populations can also have a dramatic impact on kelp, and recently, a wasting disease decreased the numbers of sea stars (a predator of urchins) statewide.
“All of these things are connected within the ecosystem,” Flores Miller says.
Kelp survey data is available to anyone who is interested – members of the general public, other governmental agencies, universities and researchers.
The dataset has many uses, both within and outside of CDFW. It is used during the review process for commercial kelp bed lease requests. It has been a critical piece of the Marine Protected Area planning process. It has been used to help predict the abundance of many kelp forest-dependent species valued by humans, such as abalone. And it has helped scientists understand issues such as the recent abalone die-off in northern California.
CDFW Photos: giant kelp and bull kelp (by Rebecca Flores Miller), and image of kelp forest near Cambria taken during the 2016 aerial kelp survey.
Tim Hermansen of CDFW carries a turkey holding box to CDFW’s Levi Sousa while John Davis clears the net.
Derek Schiewek of CDFW holds a turkey while CDFW’s Laura Cockrell measures the tarsus.
Recent efforts to determine the number of turkeys on the Upper Butte Wildlife Area have been a net success.
CDFW staff and volunteers from the National Wild Turkey Federation (NWTF) began annual turkey banding efforts in 2015 to gather information about turkey demographics and movements to facilitate better management of the population and assess future hunting opportunities. Approximately a dozen volunteers and staff have since worked on this effort two months each year, in the late winter through early spring.
Captured birds are fitted with a numbered band, and their age, gender and weight are determined before they are released. The number of times a turkey is recaptured through ongoing trapping activities, or when a hunter returns a band to CDFW, provides data about the density and the movements of the birds. Approximately 20 wild turkeys have been captured each of the past four years, using air cannons that propel nets. Last year was the sole exception, as torrential storms resulted in zero captures because portions of the property were flooded and could not be traversed with trapping equipment.
“That year was very frustrating, but part of being a wildlife biologist is going with the flow,” recalled CDFW Environmental Scientist Laura Cockrell, who is involved in coordinating and facilitating wildlife surveys on the wildlife area.
This year, walk-in traps were used for the first time to supplement the traditional use of air cannons, and the final tally was 38 turkeys banded, increasing the total number banded over the course of the project to 88. This baseline data will inform decisions on how many turkey hunters will be allowed access to the wildlife area each spring.
“Our volunteers and all our staff are what makes this project successful,” Cockrell said. “Everyone completes a safety training so we can make sure the birds are handled quickly and carefully, and then it is a lot of ‘hurry up and wait’ during the trapping operations. If we did not have a dedicated crew on this project, it would not be successful. The walk-in traps allow staff to set up trapping operations in the morning, check the site throughout the day, and process birds as they are captured.”
Also appreciative of the banding efforts were turkey hunters, who had an extra “spring” in their step this year at the Upper Butte Wildlife Area.
The 2018 spring turkey hunts recently ended after 64 hunters who hunted on Upper Butte Basin harvested 35 turkeys. During the previous three spring seasons combined since spring turkey hunts began on the wildlife area in 2015, 133 hunters participated and 47 turkeys were harvested.
All the result of field conversations between CDFW staff and fall turkey hunters.
“During the fall turkey seasons some years back, hunters at the check stations would frequently ask us when we were going to offer a spring season, which we had not done before,” Cockrell said.
At the wildlife area’s Howard Slough and Little Dry Creek units, the problem was not a lack of turkeys but rather a lack of funding to hire staff to advertise, prepare, regulate and operate the extra hunts – and a lack of scientific data to support an extra hunting season.
A collaborative effort between CDFW and the NWTF solved that problem.
In 2014, NWTF applied for and received a state grant from the Upland Game Bird Stamp Fund. The grant proposal, which was spearheaded by NWTF District Biologist Kevin Vella, obtained five years of funding to support a seasonal coordinator position.
“This spring we had almost 1,800 applications for 144 open spots,” said Cockrell. “Our hunters really appreciate the opportunities that the spring turkey hunts provide. We frequently hear after a hunt what an amazing time they had out in the field and how much they enjoyed their time on the wildlife area. One of our hunters this season was so excited because he was able to harvest a nice turkey at his very first hunt!”
All photos © National Wild Turkey Federation, all rights reserved. Top Photo: Tim Hermansen of CDFW holds a turkey while Laura Cockrell of CDFW measures its beard with calipers.
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