Boyd Deep Canyon Desert Research Center

12 Nov, 09 AM - 15 Nov, 12 AM

How has the biology of the San Jacinto Mountains changed over 100 years? In 1908, the University of California sent out the first of its expeditions to explore the biology of California?to the San Jacinto Mountain region of Riverside County. Two teams of biologists stayed in the field continuously from May to September, traveling throughout the area, from the valley floor to the mountains? summit, collecting vertebrates, taking copious notes and photographs, and ultimately publishing their results (Grinnell and Swarth 1913). This expedition is one of the cornerstones of understanding of southern California?s biology: it, and similar expeditions led by Joseph Grinnell to the San Bernardino Mountains 1905?07 and along the Colorado River in 1912, were the only intensive surveys of the fauna any region of southern California before the region was transformed forever by the flood of humanity. The expedition of 1908 thus stands as a unique benchmark, giving us the longest historic perspective possible on how the wildlife of southern California is responding to environmental change. Since 1908, however, the biology of the San Jacinto region has not received similar attention. Some smaller areas, notably Deep Canyon, where the University of California maintains a research station, have been studied intensively, but knowledge of the region as a whole has not been kept current?in part because the 1908 expedition was so thorough. Thus the value of that expedition as a benchmark has yet to be realized. Therefore, on the expedition?s centennial in 2008, the San Diego Natural History Museum, in cooperation with the University of California, Berkeley and Riverside, proposes an expedition retracing the steps of Joseph Grinnell and his associates in 1908. By visiting the same sites, spending a similar amount of time at each, we will be able to make a detailed comparison of how the region?s wildlife has changed over a century. Such a comparison, covering all species of vertebrates, will reveal what species may be of conservation concern on this island of montane forest, isolated by desert and urbanization. Such a comparison will allow the effects of multiple factors to be evaluated. Urban development is encroaching on the San Jacinto Mountains from both east and west. Development of both the San Jacinto Basin to the west and the Coachella Valley to the east has already affected wildlife seriously, as recognized in the establishment of multiple-species conservation plans for both areas. Urbanization and agriculture have already touched some of the peripheral sites surveyed in 1908. The growth of Idyllwild and smaller communities within the mountains may also have affected wildlife. Some species retreat from urbanization, while others are attracted to it. Wildfire is one of the major factors governing southern California?s biology. Our studies of the effects of the fires of 2002 and 2003 in San Diego County have already revealed many unanticipated effects on wildlife. Large fires have swept parts of the San Jacinto region recently as well. Also, suppression of fires has likely had many effects on wildlife over the past century. In San Diego County, about 25 species of woodland birds have spread south or to lower elevations in the past 100 years, possibly as a result of fire suppression. Has a similar pattern prevailed in the San Jacinto Mountains, whose central forest has not burned in recorded history? The environmental change now looming worldwide is the warming of the climate. In southern California, temperature change so far has been reflected largely in increased winter low temperatures at high elevations and in increased summer high temperatures in the desert (L. J. Hargrove and P. Unitt analysis of U.S. Weather Service data). These changes may be expected to lead to changes in animals? distribution and life history: at high elevations: mammals may remain active longer or cease hibernating entirely; birds may nest earlier in the year, winter at higher elevations, or dispense with migration. At low elevations, with higher temperatures, some mammals may estivate longer, while other mammals and birds may be so heat-stressed they are unable to reproduce or survive in parts of their former ranges. In the Yosemite region, the scientists from the Museum of Vertebrate Zoology (MVZ) at the University of California, Berkeley, have retraced the paths of another early expedition and found many changes, even in the wilderness. Many of these changes, such as the upslope spread of the pinyon mouse and the upslope contraction of the pika and alpine chipmunk, appear linked to climate warming. In the southwestern U.S., another predicted change is decreased rainfall. Prolonged drought is likely to lead to great change in animals? abundance and ranges as well. Following the extremely dry winter of 2001?02, the nesting of four species of birds near San Diego decreased almost to zero (Bolger et al. 2004), and in areas of San Diego County burned in 2002 and 2003 the abundance of many species of birds and mammals has fluctuated more in response to variations in rainfall than it has to postfire recovery of vegetation (P. Unitt and S. Tremor unpubl. data). Thus we propose an expedition to retrace the steps of Joseph Grinnell, Harry Swarth, Walter Taylor, and Charles Richardson through the San Jacinto region 100 years later. By replicating their effort we will realize the value of their work as a benchmark and establish a basis of comparison for future changes at a critical moment in history. As Grinnell himself wrote concerning the value of his work: ?This value will not, however, be realized until the lapse of many years, possibly a century, assuming that our material is safely preserved. And this is that the student of the future will have access to the original record of faunal conditions in California and the West, wherever we now work.? Coordination of our proposed resurvey of the San Jacinto region with the methods being used by MVZ elsewhere in California will allow changes to be assessed and predictions of future change to be made at an even broader scale. Scientists from MVZ have already developed the techniques and models from which these comparisons and predictions can be made. Methods Grinnell and Swarth had 20 primary base camps distributed around the San Jacinto region. We will use these as the framework for our effort. The biologists of the 1908 expedition, apportioned between two teams, spent a total of 184 team-days in the field from 1 May to 5 September. They spent from 3 to 25 days at each camp, collecting and observing around it as could be done on foot. They recorded their activities in great detail, in notebooks which the Museum of Vertebrate Zoology has scanned electronically and made available on its website (http://bscit.berkeley.edu/mvz/volumes.html?). They took about 40 photographs of the sites and marked their sites and routes on topographic maps, all of which have been scanned as well. These records will enable us to ensure that we revisit the same areas covered 100 years ago as exactly as possible. Of course, the 1908 expedition was run under constraints from which biologists working a century later have been freed. Grinnell and his team traveled by railroad, horse-drawn wagon, or on foot. As a result, they visited most sites only once. Today, all but two or three sites are accessible by motor vehicle, enabling us to spread our effort more evenly through the seasons to get a picture of the region?s biology more rounded than was possible in 1908. We propose surveying each site repeatedly, adding a visit to each site in winter, and distributing the remaining visits through the spring and summer as is appropriate for the elevation of the site and the animals? life cycle (more in the spring for low-desert sites, shifting toward summer for higher mountain sites). Furthermore, we propose spreading the effort in the field over three years. Because of the wide swings in rainfall from one year to the next, spreading the study over three years increases the chances that the study will encompass a representative sample of current climate conditions. The Museum of Vertebrate Zoology has developed a protocol for the resurveys of all its historic expeditions, and our proposed expedition to the San Jacinto region will follow this closely. The protocol is designed to replicate the effort of 1908 as closely as possible while increasing standardization that will enable the effort of 2008 to be replicated even more closely in the future. The coordination of the survey protocol also ensures that the results of the San Jacinto resurvey can be compared with those of other similar resurveys being carried out elsewhere by the University of California. Birds Birds will be sampled by three methods. Around each of the 20 camp sites, we will establish 10 points along a path corresponding as closely as possible to the area covered in 1908 while encompassing the maximum habitat diversity possible along a route that can be covered in one morning on foot. The route will be walked in the same way on each of four visits to the site. All birds along the route will be counted, with each of the 10 points being the center of an variable-distance count for 7 minutes, according to the Museum of Vertebrate Zoology?s protocol. The route will be covered between dawn and 10:00 AM. A subset that can be covered in one hour beginning at dusk will be selected for surveys of nocturnal birds. No recordings will be used on the walk out, but recordings of the relevant species may be played to elicit responses on the walk back. The routes and points will be documented by photographs and coordinates recorded by means of the global positioning system (GPS). Second, birds will be trapped by mist net, with five nets deployed around the camp sites in locations where the trapping is likely to be successful (location amid vegetation, shaded through the morning, sheltered from wind). The nets will be set up and closed in the evening, then opened before dawn the next morning. We will record the time each net is opened and closed as well as the number and identity of birds caught. The time of closure will have to be determined in the field by sun and wind conditions, but the recording of the time they are left open allows a calculation of capture rate. The nets? situation and location will be recorded by photography and GPS as for the count points. Because some camp sites are in the famously windy San Gorgonio Pass, and because mist-netting is ineffective in even light wind, we must anticipate that this technique may not always be practical at every site. Third, all birds observed incidental to other activities will be noted. Time not devoted to more structured sampling will be used to search areas visited by Grinnell and Swarth?s team on a more informal basis. For a few species with very localized distributions, such as the Black Swift and Whip-poor-will, we will make trips to previously reported sites to assess the species? current status even if they are not in areas surveyed by Grinnell and Swarth. Mammals Rodents and Insectivores Rodents will be sampled by live-trapping. At each site, we will set out a line of 40 Sherman and 10 Tomahawk traps as close as possible to Grinnell and Swarth?s trapping sites as can be determined from their field notes and as needed to sample the habitat diversity around each site. The traps will be opened for four consecutive days and nights, baited, and provided with cotton batting for the animals? insulation. The coordinates of the ends and center of each trap line will be recorded by the GPS. Shrews (and some rodents resistant to other trapping methods) will be sampled by pitfall trapping. At each site, we will set out a line or array of 20 pitfall traps consisting of 32-ounce cups buried up to their tops. Each animal trapped, by any technique, will be identified, weighed, measured (as needed for identification), photographed (as needed for identification), and marked before being released, unless it is retained as a specimen. Some species, such as the flying squirrel, may require more custom-tailored techniques for detection. Carnivores At each of the 20 camp sites we will set up three stations for detection of carnivores. The stations will be distributed to sample the habitat diversity around the sites, and the coordinates of each will be recorded by the GPS. The focus of each station will be a 12-inch metal stake wrapped around its top with a pipe cleaner and baited with a scent lure (Carman?s Pro-Choice) suitable for multiple species of carnivores. The scent is applied to the pipe cleaner with a toothbrush. Below the pipe cleaner, double-sided tape is wrapped around the stake. Placing the bait on a removable stake allows us to remove the scent after the survey. Using a toothbrush to apply lure to a pipe cleaner leaves a consistent amount of lure at each station. At each station, a Game-Vu digital camera is placed 1 to 2 meters from the stake and 20 cm off the ground. The camera is enclosed in a metal box, protecting it from weather, animals, and people (York et al 2001). The camera is activated by a motion sensor. Also, animals often rub against the stake, leaving hairs on both the pipe cleaner and the double-sided tape, and these hairs (collected and compared with hairs on museum specimens) identify the animal, providing independent corroboration of identifications from the photographs (Ernest et al 2002, Taberlet et al 1999). After an animal has visited the station, the stake is cleaned and the pipe cleaner and tape are replaced. Bats Bats will be surveyed by means of electronic detection of their sounds. At each of the 20 camp sites we will set up three Anabat detectors, distributed to sample the habitat diversity around the sites and in places where bats are likely to be active (possible roost sites, ponds). The coordinates of each will be recorded by the GPS. Each detector is placed in a weatherproof plastic container and buried underground with an extension cable connecting it to a microphone placed 1 foot above ground. Each detector will be operated from dusk to dawn through our stay at each camp site. The detector records the bats? sounds in computer memory, and we use a filtering program to sort the recordings by their time/frequency signature. We use the program Analook 6 to convert the recordings to sonagrams, then compare the sonagrams visually with a library of bat calls to identify the species. Spot-lighting Some mammals, especially ungulates and rabbits, are best recorded visually. At each camp, we will establish a spot-lighting survey route. In this technique, a team of two mammalogists, each carrying a spotlight, will walk together along a pre-established route at night. Each shines the light back and forth through 180? on one side of the route, covering the full field of vision. Animals are located by their reflected eyeshine and identified through binoculars or spotting scope. The color of the eyeshine also helps identify the species. The location, distance, and direction of the animal are recorded, as with the variable-distance point counts of birds. All mammals observed incidental to other activities will be noted. Specimens Animals will be collected under permit from the California Department of Fish and Game and U.S. Fish and Wildlife Service (for birds), with a goal of up to three specimens per species per site. Specimens are needed because of the long time-scale on which this study is based and to uphold the highest standard of scientific documentation. Just as the concepts and definitions of some species have changed from 1908 to the present, these are likely to continue changing. For example, Grinnell and Swarth recognized only two species of chipmunk in the San Jacinto Mountains, yet it is now known there are actually three. Without collected specimens the identification of the chipmunks recorded by Grinnell and Swarth would have been lost. Some species, even some with profound differences in biology, differ only subtly in external appearance, making voucher specimens essential to confirming identifications. For birds, migratory individuals often mix with resident populations, and dissection, assessment of physiological condition, and identification of specimens to subspecies are needed in these cases to evaluate a bird?s status accurately. An accurate understanding of what is going on inside an animal is essential to interpreting changes, which can be represented by changes in seasonal activity, breeding, and migration as well as simple occurrence. Furthermore, analysis of DNA may give perspective on a population?s history of dispersal or isolation, so preserving samples of genetic material, with specimens to attest to the samples? identity, is also critical. It is our goal that a new expedition also serve as a basis for evaluation of future changes. Just as we judge the value of the 1908 expedition, ultimately, on the specimens and data Grinnell and Swarth left for us to evaluate, future generations will judge our effort on the same basis. Schedule We will spend 12 days at each of the 20 camp sites surveying for birds (with a team of two ornithologists) and 12 days at each site surveying for mammals (with a team of three mammalogists). Grinnell, Swarth, Taylor, and Richardson spent a total of 184 team-days in the field in 1908. For the bird surveys, our schedule entails 180 days in the spring and summer (thus closely paralleling the 1908 expedition) plus 60 days in the winter. The bird surveys will be distributed in four three-day visits to each site: one in winter and three in spring or summer, as appropriate for the elevation of the site. For example, in the low desert the surveys might take place in March, April, and May, whereas at the higher elevations of the San Jacinto Mountains they might take place in June, July, and August. Each site will be visited once in the spring or summer each year from 2008 to 2010. Half of the sites will be visited in winter 2008?09, the other half in winter 2009?10. Thus the field work will be completed in summer 2010. The mammal surveys will be distributed in three five-day visits to each site: one in winter and two in spring or summer, as appropriate for the elevation of the site. Two-thirds of the sites will be visited in spring or summer each year from 2008 to 2010. Half of the sites will be visited in winter 2008?09, the other half in winter 2009?10, as for birds. The reason for the difference in the schedules is that for birds it is more important to spread the effort through the season, while for trapping mammals it is more important to trap on four consecutive nights. It is not necessary that the bird and mammal surveys coincide with each other. Products We will compare the distribution and abundance of each species as we observe it 2008?2010 with the distribution and abundance recorded by Grinnell and Swarth in 1908. We will identify the pattern of change for each species and evaluate the magnitude of that change. We will categorize species by type of change and look for aspects of their biology that are shared and may help explain the basis for the change. Examples of possible categories include spread to higher elevations, retreat from lower elevations, spread to lower elevations, retreat from higher elevations, attraction to urban development, and retreat from urban development. We plan publication our results in a scientific periodical, much as Grinnell and Swarth published their results in the University of California Publications in Zoology. We also plan to make the results available through the websites of the San Diego Natural History Museum and the University of California, Berkeley. We plan to speak about the results at both scientific conferences and events for the general public, such as lectures and classes offered by the San Diego Natural History Museum. The study may lead to field trips where we bring people interested in nature to the San Jacinto region to familiarize them with our work first-had; the San Diego Natural History Museum offers an extensive program of such field trips. We anticipate considerable interest in the study from the news media, as MVZ has received from its parallel study of the Yosemite region. Thus newspaper articles, radio interviews, and television programs are likely to emerge from the study to familiarize the public about the San Jacinto region?s diverse biology and the unique opportunity the 1908 expedition made possible. Personnel Philip Unitt, ornithologist, has been the collection manager for the San Diego Natural History Museum?s department of birds and mammals since 1988. He has published over 30 papers on the distribution, ecology, identification, and conservation of birds, primarily in southern California. He was a co-author of Birds of the Salton Sea: Status, Biogeography, and Ecology, published by University of California Press in 2003, and the San Diego County Bird Atlas, published by the San Diego Natural History Museum in 2004. The latter project, entailing the directing of hundreds of volunteers and building and analyzing a database of about 400,000 records, was even more ambitious than the expedition to the San Jacinto region we propose here. Brad Hollingsworth Scott Tremor, mammalogist, has been on the San Diego Natural History Museum?s staff since 2004, following 16 years of working with the mammal collection at the San Diego Zoo. He has 20 years of experience in mammal trapping and monitoring, working with rodents, bats, and carnivores. He has overseen biological inventories, conducted studies of wildlife corridors, and taught classes in mammal identification, biology, and tracking. Since 2003 he has organized and supervised studies of the effects of wildfire on mammals in San Diego County sponsored by the Joint Fire Science Program and Cleveland National Forest. Tremor is also a PI on the San Diego County Mammal Atlas project which is expected to be published in 2008. Lori Hargrove, ornithologist and ecologist, will be completing her Ph.D. at the University of California, Riverside, in 2008. Her dissertation research is addressing elevational shifts in the distribution of birds along the slopes of the Peninsular Ranges in response to climate change, for which she received the Cooper Ornithological Society?s Mewaldt-King award in 2005. Her study area overlaps with the San Jacinto Mountains, including some of the sites we will visit as part of the study we propose here. For Cleveland National Forest Lori developed a survey protocol for the Gray Vireo, a rare species for which the San Jacinto Mountains are home to a critical population. Dana Hogan, mammalogist, has worked as a research technician on mammal studies since 2002. Her projects have including trapping and study of the endangered Pacific Little Pocket Mouse at Camp Pendleton, study of the effects on mammals of the Cedar Fire of 2003, studies of the effects of habitat fragmentation on mammals and reptiles, and inventories of the mammals of Cabrillo National Monument and the San Felipe Valley Wildlife Area. The project will offer opportunities for graduate students to participate and perhaps design their theses around our proposed studies. We anticipate the project will use numerous volunteers and associates as well, helping with bird counts, handling mist nets, helping with mammal trapping, and preparing specimens, among other tasks. The San Diego Natural History Museum organizes a vast corps of volunteers to help with all aspects of its operations.

Visit #13986 @Boyd Deep Canyon Desert Research Center

Approved

Under Project # 9132 | Research

Centennial Resurvey of San Jacinto Mountains

research_scientist - San Diego Natural History Museum

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Lori Hargrove Nov 12 - 15, 2007 (4 days)
Group of 2 Research Scientist/Post Doc Nov 12 - 15, 2007 (4 days)

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Mayhew housing facilities 3 Nov 12 - 15, 2007