Large carnivores are declining globally, with strong direct and indirect ecological impacts on protected area networks (PANs). Human encroachment on ecosystems is a global threat for large ...carnivores, particularly in savanna Africa, where increasing human resource demands continue to degrade the connectivity and viability PANs. Zambia has a regionally significant role in large carnivore conservation, given that it borders eight countries, includes three transfrontier conservation areas (TFCAs), and manages nearly 40 % of its land for wildlife. Deforestation in general and encroachment in particular are recognized problems in Zambian natural resource management. However, specific impacts on PANs are poorly understood owing to a lack of adequate mapping of encroachment, deriving from widespread difficulty in mapping cultivation and clearing in fire-prone savannas, and severe inaccuracy in several previous land cover data sets. Using simple manual interpretation of diverse and carefully chosen remote sensing imagery, we evaluated land use change from 1965 to 2011 in Zambia, primarily in the Luangwa Valley. We found widespread encroachment extending toward national parks from major roads as fast as 2 km/year and averaging 18 hectares per hour of daylight throughout a 159,805 km
2
study area, eliminating designated buffer zones in some areas, decreasing connectivity, and potentially eliminating viable TFCAs. At current rates, Zambia’s PANs would be expected to be reduced into small isolated pockets primarily centered on national parks, with substantial human edge effects threatening the viability of wildlife populations in the region, particularly wide-ranging, low density, and threatened large carnivores such as African wild dogs, cheetah, and lion. It is thus critical that encroachment is accurately mapped across the entire region and that land use plans are developed, implemented, revised where necessary, and enforced with strong governmental support, enabling protection of these areas and the communities that depend upon them.
We analyse the large-scale correlation function of the 6dF Galaxy Survey (6dFGS) and detect a baryon acoustic oscillation (BAO) signal at 105 h
−1 Mpc. The 6dFGS BAO detection allows us to constrain ...the distance-redshift relation at z
eff= 0.106. We achieve a distance measure of DV
(z
eff) = 457 ± 27 Mpc and a measurement of the distance ratio, r
s(z
d)/DV
(z
eff) = 0.336 ± 0.015 (4.5 per cent precision), where r
s(z
d) is the sound horizon at the drag epoch z
d. The low-effective redshift of 6dFGS makes it a competitive and independent alternative to Cepheids and low-z supernovae in constraining the Hubble constant. We find a Hubble constant of H
0= 67 ± 3.2 km s−1 Mpc−1 (4.8 per cent precision) that depends only on the Wilkinson Microwave Anisotropy Probe-7 (WMAP-7) calibration of the sound horizon and on the galaxy clustering in 6dFGS. Compared to earlier BAO studies at higher redshift, our analysis is less dependent on other cosmological parameters. The sensitivity to H
0 can be used to break the degeneracy between the dark energy equation of state parameter w and H
0 in the cosmic microwave background data. We determine that w=−0.97 ± 0.13, using only WMAP-7 and BAO data from both 6dFGS and Percival et al. (2010).
We also discuss predictions for the large-scale correlation function of two future wide-angle surveys: the Wide field ASKAP L-band Legacy All-sky Blind surveY (WALLABY) blind H i survey (with the Australian Square Kilometre Array Pathfinder, ASKAP) and the proposed Transforming Astronomical Imaging surveys through Polychromatic Analysis of Nebulae (TAIPAN) all-southern-sky optical galaxy survey with the UK Schmidt Telescope. We find that both surveys are very likely to yield detections of the BAO peak, making WALLABY the first radio galaxy survey to do so. We also predict that TAIPAN has the potential to constrain the Hubble constant with 3 per cent precision.
Protected area managers need reliable information to detect spatial and temporal trends of the species they intend to protect. This information is crucial for population monitoring, understanding ...ecological processes, and evaluating the effectiveness of management and conservation policies. In under-funded protected areas, managers often prioritize ungulates and carnivores for monitoring given their socio-economic value and sensitivity to human disturbance. Aircraft-based surveys are typically utilized for monitoring ungulates because they can cover large areas regardless of the terrain, but such work is expensive and subject to bias. Recently, unmanned aerial vehicles have shown great promise for ungulate monitoring, but these technologies are not yet widely available and are subject to many of the same analytical challenges associated with traditional aircraft-based surveys. Here, we explore use of inexpensive and robust distance sampling methods in Kafue National Park (KNP) (22,400 km
2
), carried out by government-employed game scouts. Ground-based surveys spanning 101, 5-km transects resulted in 369 ungulate group detections from 20 species. Using generalized linear models and distance sampling, we determined the environmental and anthropogenic variables influencing ungulate species richness, density, and distribution. Species richness was positively associated with permanent water and percent cover of closed woodland vegetation. Distance to permanent water had the strongest overall effect on ungulate densities, but the magnitude and direction of this effect varied by species. This ground-based approach provided a more cost-effective, unbiased, and repeatable method than aerial surveys in KNP, and could be widely implemented by local personnel across under-funded protected areas in Africa.
ABSTRACT Data Release 5 (DR5) of the Radial Velocity Experiment (RAVE) is the fifth data release from a magnitude-limited ( ) survey of stars randomly selected in the Southern Hemisphere. The RAVE ...medium-resolution spectra ( ) covering the Ca-triplet region (8410-8795 ) span the complete time frame from the start of RAVE observations in 2003 to their completion in 2013. Radial velocities from 520,781 spectra of 457,588 unique stars are presented, of which 255,922 stellar observations have parallaxes and proper motions from the Tycho-Gaia astrometric solution in Gaia DR1. For our main DR5 catalog, stellar parameters (effective temperature, surface gravity, and overall metallicity) are computed using the RAVE DR4 stellar pipeline, but calibrated using recent K2 Campaign 1 seismic gravities and Gaia benchmark stars, as well as results obtained from high-resolution studies. Also included are temperatures from the Infrared Flux Method, and we provide a catalog of red giant stars in the dereddened color interval (0.50, 0.85) for which the gravities were calibrated based only on seismology. Further data products for subsamples of the RAVE stars include individual abundances for Mg, Al, Si, Ca, Ti, Fe, and Ni, and distances found using isochrones. Each RAVE spectrum is complemented by an error spectrum, which has been used to determine uncertainties on the parameters. The data can be accessed via the RAVE Web site or the VizieR database.
African lions (Panthera leo) are declining continent-wide, with protected area populations subject to a variety of anthropogenic effects. Zambia contains viable lion populations of considerable ...importance for photographic and hunting tourism, but long-term lion demographic data do not exist to guide recent management directives and population projections under different strategies. We described population size, as well as age and sex structure of lions in 3 Zambian national park populations bordering hunting areas, and found them to be male-depleted relative to other systems. We then estimated rates of adult male loss leading to male depletion in these populations and the effect of different future hunting management options on population characteristics. Predictions from matrix population models constructed within a Bayesian framework confirmed that the observed population structure was likely due to high rates of adult male loss and that instituting age limits on male harvests with quota reductions would reduce male depletion, improve tourism by providing older and more abundant males, and slightly increase population size. Reducing male mortality from wire snare poaching would also result in similar demographic impacts, and in concert with changes in hunting regulations would substantially improve the quality and quantity of adult male lions. However, model results varied depending on whether we assumed historical population stability. Predictions assuming negative historical growth rate indicated that substantially more conservative lion harvest management is warranted. We discuss the relevance of these findings for maintaining viable lion populations in and around protected areas in Zambia.
We present a detailed analysis of redshift-space distortions in the two-point correlation function of the 6dF Galaxy Survey (6dFGS). The K-band selected subsample which we employ in this study ...contains 81 971 galaxies distributed over 17 000 degree2 with an effective redshift z
eff= 0.067. By modelling the 2D galaxy correlation function,
, we measure the parameter combination f(z
eff)σ8(z
eff) = 0.423 ± 0.055, where
is the growth rate of cosmic structure and σ8 is the rms of matter fluctuations in 8 h
−1 Mpc spheres.
Alternatively, by assuming standard gravity we can break the degeneracy between σ8 and the galaxy bias parameter b. Combining our data with the Hubble constant prior from Riess et al., we measure σ8= 0.76 ± 0.11 and Ωm= 0.250 ± 0.022, consistent with constraints from other galaxy surveys and the cosmic microwave background data from Wilkinson Microwave Anisotropy Probe 7 (WMAP7).
Combining our measurement of fσ8 with WMAP7 allows us to test the cosmic growth history and the relationship between matter and gravity on cosmic scales by constraining the growth index of density fluctuations, γ. Using only 6dFGS and WMAP7 data we find γ= 0.547 ± 0.088, consistent with the prediction of General Relativity. We note that because of the low effective redshift of the 6dFGS our measurement of the growth rate is independent of the fiducial cosmological model (Alcock-Paczynski effect). We also show that our conclusions are not sensitive to the model adopted for non-linear redshift-space distortions.
Using a Fisher matrix analysis we report predictions for constraints on fσ8 for the Wide-field Australian SKA Pathfinder telescope L-band Legacy All-sky Blind surveY (WALLABY) and the proposed Transforming Astronomical Imaging surveys through Polychromatic Analysis of Nebulae (TAIPAN) survey. The WALLABY survey will be able to measure fσ8 with a precision of 4-10 per cent, depending on the modelling of non-linear structure formation. This is comparable to the predicted precision for the best redshift bins of the Baryon Oscillation Spectroscopic Survey, demonstrating that low-redshift surveys have a significant role to play in future tests of dark energy and modified gravity.
We present part 2 of the sixth and final Data Release (DR6) of the Radial Velocity Experiment (Rave), a magnitude-limited ( ) spectroscopic survey of Galactic stars randomly selected in Earth's ...southern hemisphere. The Rave medium-resolution spectra (R ∼ 7500) cover the Ca triplet region (8410-8795 ) and span the complete time frame from the start of Rave observations on 2003 April 12 to their completion on 2013 April 4. In the second of two publications, we present the data products derived from 518,387 observations of 451,783 unique stars using a suite of advanced reduction pipelines focusing on stellar atmospheric parameters, in particular purely spectroscopically derived stellar atmospheric parameters ( , , and the overall metallicity), enhanced stellar atmospheric parameters inferred via a Bayesian pipeline using Gaia DR2 astrometric priors, and asteroseismically calibrated stellar atmospheric parameters for giant stars based on asteroseismic observations for 699 K2 stars. In addition, we provide abundances of the elements Fe, Al, and Ni, as well as an overall /Fe ratio obtained using a new pipeline based on the GAUGUIN optimization method that is able to deal with variable signal-to-noise ratios. The Rave DR6 catalogs are cross-matched with relevant astrometric and photometric catalogs, and are complemented by orbital parameters and effective temperatures based on the infrared flux method. The data can be accessed via the Rave website (http://rave-survey.org) or the Vizier database.
The Radial Velocity Experiment (Rave) is a magnitude-limited (9 < I < 12) spectroscopic survey of Galactic stars randomly selected in Earth's southern hemisphere. The Rave medium-resolution spectra ...(R ∼ 7500) cover the Ca-triplet region (8410-8795 ). The sixth and final data release (DR6) is based on 518,387 observations of 451,783 unique stars. Rave observations were taken between 2003 April 12 and 2013 April 4. Here we present the genesis, setup, and data reduction of Rave as well as wavelength-calibrated and flux-normalized spectra and error spectra for all observations in Rave DR6. Furthermore, we present derived spectral classification and radial velocities for the Rave targets, complemented by cross-matches with Gaia DR2 and other relevant catalogs. A comparison between internal error estimates, variances derived from stars with more than one observing epoch, and a comparison with radial velocities of Gaia DR2 reveals consistently that 68% of the objects have a velocity accuracy better than 1.4 km s-1, while 95% of the objects have radial velocities better than 4.0 km s-1. Stellar atmospheric parameters, abundances and distances are presented in a subsequent publication. The data can be accessed via the Rave website (http://rave-survey.org) or the Vizier database.
This paper presents the detailed abundances and r-process classifications of 126 newly identified metal-poor stars as part of an ongoing collaboration, the R-Process Alliance. The stars were ...identified as metal-poor candidates from the RAdial Velocity Experiment (RAVE) and were followed up at high spectral resolution (R ∼ 31,500) with the 3.5 m telescope at Apache Point Observatory. The atmospheric parameters were determined spectroscopically from Fe i lines, taking into account non-LTE corrections and using differential abundances with respect to a set of standards. Of the 126 new stars, 124 have Fe/H < −1.5, 105 have Fe/H < −2.0, and 4 have Fe/H < −3.0. Nine new carbon-enhanced metal-poor stars have been discovered, three of which are enhanced in r-process elements. Abundances of neutron-capture elements reveal 60 new r-I stars (with +0.3 ≤ Eu/Fe ≤ +1.0 and Ba/Eu < 0) and 4 new r-II stars (with Eu/Fe > +1.0). Nineteen stars are found to exhibit a "limited-r" signature (Sr/Ba > +0.5, Ba/Eu < 0). For the r-II stars, the second- and third-peak main r-process patterns are consistent with the r-process signature in other metal-poor stars and the Sun. The abundances of the light, , and Fe-peak elements match those of typical Milky Way (MW) halo stars, except for one r-I star that has high Na and low Mg, characteristic of globular cluster stars. Parallaxes and proper motions from the second Gaia data release yield UVW space velocities for these stars that are consistent with membership in the MW halo. Intriguingly, all r-II and the majority of r-I stars have retrograde orbits, which may indicate an accretion origin.
Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii are waterborne protozoal pathogens distributed worldwide and empirical evidence suggests that wetlands reduce the concentrations of ...these pathogens under certain environmental conditions. The goal of this study was to evaluate how protozoal removal in surface water is affected by the water temperature, turbidity, salinity, and vegetation cover of wetlands in the Monterey Bay region of California. To examine how protozoal removal was affected by these environmental factors, we conducted observational experiments at three primary spatial scales: settling columns, recirculating wetland mesocosm tanks, and an experimental research wetland (Molera Wetland). Simultaneously, we developed a protozoal transport model for surface water to simulate the settling columns, the mesocosm tanks, and the Molera Wetland. With a high degree of uncertainty expected in the model predictions and field observations, we developed the model within a Bayesian statistical framework. We found protozoal removal increased when water flowed through vegetation, and with higher levels of turbidity, salinity, and temperature. Protozoal removal in surface water was maximized (~0.1hour−1) when flowing through emergent vegetation at 2% cover, and with a vegetation contact time of ~30minutes compared to the effects of temperature, salinity, and turbidity. Our studies revealed that an increase in vegetated wetland area, with water moving through vegetation, would likely improve regional water quality through the reduction of fecal protozoal pathogen loads.
•Water flowing through vegetation had strongest effect of increasing removal.•Higher levels of turbidity, salinity, and temperature increase protozoal removal.•Under optimized conditions, >99% protozoal removal estimated to occur.•Wetlands may mitigate impacts of protozoal pathogens in coastal environments.
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