Estimating Baseline Population Parameters of Urban and Wildland Black Bear Populations Using a DNA-Based Capture-Mark-Recapture Approach in Mono County, California

Prior to European settlement, black bear (Ursus americanus) were far less abundant in the state of California. Estimates from statewide harvest data indicate the California black bear population has tripled in the last 3 decades. Bears inhabit areas they formally never occurred (e.g., urban environments) and populations that were at historically low densities are now at high densities. Though harvest data are useful and widely used as an index for black bear population size and population demographics statewide, it lacks the ability to produce precise estimates of abundance and density at local scales or account for the numerous bears living in non-hunted areas. As the human population continues to expand into wildlife habitat, we are being forced to confront controversial issues about wildlife management and conservation. Habituated bears living in non-hunted, urban areas have been and continue to be a major concern for wildlife managers and the general public. My objective was to develop DNA-based capture-mark-recapture (CMR) survey techniques in wildland and urban environments in Mono County, California to acquire population size and density at local scales from 2010 to 2012. I also compared population density between the urban and wildland environment. To my knowledge, DNA-based CMR surveys for bears have only been implemented in wildland or rural environments. I made numerous modifications to the techniques used during wildland DNA-based CMR surveys to survey bears in an urban environment. I used a higher density of hair-snares than typically used in wildland studies, non-consumable lures, modified hair-snares for public safety, included the public throughout the entire process, and surveyed in the urban-wildland interface as well as the city center. These methods were efficient and accurate while maintaining human safety. I determined that there is likely a difference in population density between the urban and wildland environments. Population density was 1.6 to 2.5 times higher in the urban study area compared to the wildland study area. Considering the negative impacts urban environments can have on wildland bear populations, this is a serious management concern. The densities I found were similar to those found in other urban and wildland black bear populations. The baseline data acquired from this study can be used as part of a long-term monitoring effort. By surveying additional years, population vital rates such as apparent survival, recruitment, movement, and finite rate of population change can be estimated

Best management practices in counting urban black bears

DNA-based capture-mark-recapture (CMR) techniques are commonly used to obtain population parameters of black bears (Ursus americanus) in rural and wildland landscapes; however, these techniques have not been implemented in urban clusters (i.e., 2,500 to 50,000 residents). Black bears can readily habituate to urban clusters, and wildlife managers need to monitor and manage these urban bear populations. We modified DNAbased CMR for black bear using hair-snares to take into account the small home ranges of urban bears, urban bear behavior, and human safety within Mammoth Lakes, California, USA. We conducted this study for 3 fi eld seasons in 2010, 2011, and 2012 from June to July. Each fi eld season, we implemented a CMR with 6 encounter occasions, each 7 days in length. We used the traditional corral hair-snare design modified for human safety and chose multiple non-consumable and minimally consumable lure types to prevent food conditioning and a trap-happy response. In 2012, we also tested 3 additional hair-snare designs more appropriate for urban areas: natural rub, haphazard-wire snare, and tennis ball snare. In 2010, we collected an insufficient number of hair samples for CMR by putting hair-snares in the periphery of the urban cluster, which we call the urban–wildland interface. However, in 2011 and 2012, when we put hair-snares in the city center as well as the surrounding urban–wildlife interface and increased hair-snare density, we obtained a sufficient number of hair samples to estimate population density using closed capture CMR models. These adjustments to hairsnaring study design in urban areas helped increase capture and recapture rates to be similar to our wildland area. To achieve high capture rates using hair-snares in the urban area, we put out hair-snares at a density approximately 4 times greater than in our wildland study area and distributed them throughout the entire urban area, and not just on the urban–wildlife interface. In addition, setting hair-snares near anthropogenic features used by bears in urban areas (e.g., culverts, utility poles, dumpsters) and adding spent cooking oil to lures also increased our capture rate. Finally, the corral hair-snare had the highest capture rates of our 4 hair-snare designs. After adapting a study design for hair-snaring wildland bears, our methods were efficient for urban areas, having high capture and recapture rates (\u3e0.30) and good precision for abundance estimates (coefficient of variatio

Comparing urban and wildland bear densities with a DNA-based capture-mark-recapture approach

California’s black bear (Ursus americanus) population has tripled over the last 3 decades, causing an increased incidence of human–bear conflicts, many of which now occur in urban areas. Consequently, it is imperative that bear managers have the ability to monitor population parameters in both wildland and urban environments to help manage bears. Capture-mark-recapture (CMR) methods using uniquely typed genetic samples (DNA) collected via hair-snares have been widely used to monitor bears in wildland areas. However, we are unaware of researchers applying this technique to bears occupying urban areas. We implemented a multi-year DNA-based CMR study to compare bear densities between an urban area and a nearby wildland area. We deployed hair-snares for 6 weekly capture occasions during June and July, 2011 and 2012. We uniquely typed DNA from snared hair follicles using 14 microsatellite loci and 2 sexing loci. We coupled unique identification with robust-design closed-capture models and model averaging in Program MARK to estimate abundance. We identified 41 and 62 individual bears on the urban and wildland study areas, with average densities of 3.8 and 1.8 bears/10 km2,respectively. Our data support the hypothesis that bears can occur at greater densities in urban areas. Based on these results, we recommend using DNA-based CMR methods to monitor populations of bears in urban areas, but we suggest increasing the density of sampling locations to account for greater bear densities. Furthermore, we contend that DNA-based CMR can also estimate survival, recruitment, rate of population change (λ), and identify movement patterns by incorporating additional survey years

Extensive Geographic Mosaicism in Avian Influenza Viruses from Gulls in the Northern Hemisphere

Due to limited interaction of migratory birds between Eurasia and America, two independent avian influenza virus (AIV) gene pools have evolved. There is evidence of low frequency reassortment between these regions, which has major implications in global AIV dynamics. Indeed, all currently circulating lineages of the PB1 and PA segments in North America are of Eurasian origin. Large-scale analyses of intercontinental reassortment have shown that viruses isolated from Charadriiformes (gulls, terns, and shorebirds) are the major contributor of these outsider events. To clarify the role of gulls in AIV dynamics, specifically in movement of genes between geographic regions, we have sequenced six gull AIV isolated in Alaska and analyzed these along with 142 other available gull virus sequences. Basic investigations of host species and the locations and times of isolation reveal biases in the available sequence information. Despite these biases, our analyses reveal a high frequency of geographic reassortment in gull viruses isolated in America. This intercontinental gene mixing is not found in the viruses isolated from gulls in Eurasia. This study demonstrates that gulls are important as vectors for geographically reassorted viruses, particularly in America, and that more surveillance effort should be placed on this group of birds

Factors Influencing Mortality of Eared Grebes (Podiceps Nigricollis) During a Mass Downing

During the fall, hundreds of thousands of Eared Grebes (Podiceps nigricollis) stage on the Great Salt Lake, Utah. Mortalities resulting from birds being forced to the ground (downings) during migration occur every few years. A large (\u3e7,000 birds) die-off of migrating Eared Grebes occurred 12 December 2011 in and around Cedar City, Utah. We examined body condition, age, sex, and heavy metal concentrations among downed birds and those that still occupied the Great Salt Lake both pre- and post-downing. Eared Grebes that we collected pre-downing were heavier (523 g) than deceased birds (433 g). Body weight (g) and subcutaneous fat thickness (mm) were lower in downed birds than pre-downing birds, likely the result of the 400-km flight from the staging area to Cedar City. Liver, heart, and intestine weights were all significantly greater in both pre- and post-downing birds than downed birds. This may be because of tissue catabolism during flight or incomplete physiological changes before migration. Adult biased age ratios were observed in all groups but pre-downing (34 adults: 5 juveniles) and post-downing (39: 2) groups were less biased than the downed group (100∶ 1). Mercury and selenium wet weight concentrations in all groups were above the level observed to impact some birds\u27 reproduction and locomotion. Mercury concentrations in the liver ranged from 4.4–25.8 ppm wet weight and mercury concentrations measured in birds collected pre- and post-downing were lower than downed birds. Despite high levels of mercury and selenium, no adverse effects of heavy metal contamination have been noted in studies of Eared Grebes on the Great Salt Lake. Weather was likely the proximate cause of the downing, but impacts of heavy metal toxicity should be examined further to determine their effect on migrating Eared Grebes

Vitamin D and Chronic Kidney Disease Association with Mineral and Bone Disorder: An Appraisal of Tangled Guidelines

Chronic kidney disease (CKD) is a highly prevalent condition worldwide in which the kidneys lose many abilities, such as the regulation of vitamin D (VD) metabolism. Moreover, people with CKD are at a higher risk of multifactorial VD deficiency, which has been extensively associated with poor outcomes, including bone disease, cardiovascular disease, and higher mortality. Evidence is abundant in terms of the association of negative outcomes with low levels of VD, but recent studies have lowered previous high expectations regarding the beneficial effects of VD supplementation in the general population. Although controversies still exist, the diagnosis and treatment of VD have not been excluded from nephrology guidelines, and much data still supports VD supplementation in CKD patients. In this narrative review, we briefly summarize evolving controversies and useful clinical approaches, underscoring that the adverse effects of VD derivatives must be balanced against the need for effective prevention of progressive and severe secondary hyperparathyroidism. Guidelines vary, but there seems to be general agreement that VD deficiency should be avoided in CKD patients, and it is likely that one should not wait until severe SHPT is present before cautiously starting VD derivatives. Furthermore, it is emphasized that the goal should not be the complete normalization of parathyroid hormone (PTH) levels. New developments may help us to better define optimal VD and PTH at different CKD stages, but large trials are still needed to confirm that VD and precise control of these and other CKD-MBD biomarkers are unequivocally related to improved hard outcomes in this population