24 research outputs found

    Temporal Trends in Florida Panther Food Habits

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    Once on the brink of extinction, the Florida panther (Puma concolor coryi) has reoccupied parts of its extirpated range in southern Florida, USA over the past 20 years, which has largely been attributed to genetic restoration efforts initiated in 1995 to combat inbreeding depression and subsequent deleterious traits. Concurrent to the resurgence, an increase in documented livestock depredation events has heightened concern over human– panther conflicts. We examined 312 stomach content, scat, and feces (large intestine contents) samples collected 1989 to 2014 across the endemic range in southern Florida. We compared frequency of occurrence of prey items in samples by temporal (pre- and post-genetic restoration), geographic (north and south of 26° 10.017′ latitude), and demographic (age and sex) categories. We observed an apparent temporal shift in prey item occurrence in scats, where raccoon (Procyon lotor) occurrence increased while wild hog (Sus scrofa) occurrence decreased, whereas white-tailed deer (Odocoileus virginianus) occurrence appeared constant. Post-genetic restoration, we observed a geographic difference in panther prey, where white-tailed deer and raccoons were consumed more commonly in the southern part of the study area (characterized by lower soil quality and higher hydrological fluctuations), while wild hogs were consumed more frequently in the northern part of the study area. Neither sex nor age appeared to affect frequency of prey occurrence. Pets and livestock were not frequently found in the samples we examined. Overall, our results show shifts in panther diets both temporally and geographically; however, no notable changes in frequency of livestock found in panther diets were observed

    Effects of Climatic Variation and Reproductive Trade-offs Vary by Measure of Reproductive Effort in Greater Sage-Grouse

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    Research on long-lived iteroparous species has shown that reproductive success may increase with age, until the onset of senescence, and that prior reproductive success may influence current reproductive success. Such complex reproductive dynamics can complicate conservation strategies, especially for harvested species. Further complicating the matter is the fact that most studies of reproductive costs are only able to evaluate a single measure of reproductive effort. We systematically evaluated the effects of climatic variation and reproductive trade-offs on multiple reproductive vital rates for greater sage-grouse (Centrocercus urophasianus; sage-grouse), a relatively long-lived galliforme of conservation concern throughout western North America. Based on over a decade of field observations, we hypothesized that reproduction is influenced by previous reproductive success. We monitored hen reproductive activity from 1998 to 2010, and used generalized linear mixed models to assess effects of climate and previous reproductive success on subsequent reproductive success. Reproductive trade-offs manifested as chronic effects on subsequent reproduction and were not apparent in all measures of subsequent reproduction. Neither nest initiation nor clutch size were found to be affected by climatic variables (either year t - 1 or t) or previous reproductive success. However, both nest and brood success were affected by climatic variation and previous reproductive success. Nest success was highest in years with high spring snowpack, and was negatively related to previous brood success. Brood success was positively influenced by moisture in April, negatively associated with previous nest success, and positively influenced by previous brood success. Both positive and negative effects of previous reproduction on current year reproduction were observed, possibly indicating high levels of individual heterogeneity in female reproductive output. Our results support previous research in indicating that climatic variability may have significant negative impacts on reproductive rates

    Observation of gravitational waves from the coalescence of a 2.5−4.5 M⊙ compact object and a neutron star

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    Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

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    Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

    Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

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    Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

    Ultralight vector dark matter search using data from the KAGRA O3GK run

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    Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

    \u3cem\u3eOpinion\u3c/em\u3e The “Non-Native” Enigma

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    Non-native species have been introduced to ecosystems throughout the world, and in some instances, have degraded the invaded system. Consequently, the distinction between native and non-native species has become an integral component of conservation planning. Recently however, the conservation value of the distinction has been questioned. We examine how the native versus non-native dichotomy is intrinsically ambiguous, which therefore limits the conservation utility of the designation in and of itself. A large degree of uncertainty exists as to whether many species are or are not native. Measures outside the non-native dichotomy (e.g., impacts, evolutionary ecology, paleontology) could better inform conservation efforts, because species’ ranges are part of dynamic processes. We recommend that the � eld of conservation should avoid arbitrary points in history as benchmarks and incorporate findings from multiple disciplines to better manage resources

    Factors Affecting Greater Sage-Grouse (Centrocercus Urophasianus) Survival and Movement in South-Central Utah

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    Greater sage-grouse (Centrocercus urophasianus) adult and juvenile survival have been identified as critical demographic parameters. However, little is known regarding the dynamics of juvenile sage-grouse. From 2008-2010, I used radio-telemetry and 2 transmitter types to monitor 91 juvenile sage-grouse. Program MARK was used to analyze survival data. Over-winter survival was 0.802 - 0.982 and 0.687 - 0.969 for females and males, respectively. Fall survival rates were 0.522 - 0.623 for females and 0.332 - 0.449 for males. Survival from fall through winter was 0.418 - 0.616 for females and 0.228 - 0.435 for males. For both years combined, the probability predation caused death was 0.705, and probability harvest caused death was 0.159. The probability unreported harvest caused death was 0.091. Sex (p= 0.103) and transmitter type (p = 0.09) affected survival. Back-mounted transmitters negatively affected survival and their use should be avoided to minimize experimental bias
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