The predicted relationship between home-range size and group mass in primates developed by Clutton-Brock and Harvey (1977) has proved extremely robust in describing the use of space by most primate ...species. However, mandrills (Mandrillus sphinx) are now known to have an extreme group mass in the wild, far larger than that of the species used originally to generate that relationship, and so it was unknown whether this relationship would be robust for this species. We investigated the home-range size and use of a wild horde of ca. 700 mandrills in Lopé National Park, Gabon, using radiotelemetry. The total area the horde used over a 6-yr period 100% minimum convex polygon (MCP) was 182 km², including 89 km² of suitable forest habitat. Mandrills used gallery forests and isolated forest fragments with high botanical diversity far more intensively that the continuous forest and completely avoided savanna and marsh. Peeled polygons and fixed kernel contours revealed multiple centres of use, with the horde spending more than half its time in <10% of the total documented range, typical of a frugivore using a patchy environment. Home-range size and internal structure varied considerably between years, but total home range fitted the predicted relationship between group mass and home range size, despite being an outlier to the dataset. We discuss the conservation implications of the species' space requirements, in light of current pressures on land use in their range.
This study evaluates the potential impact of clouds on ecosystem CO2 and CO2 isotope fluxes (“isofluxes”) in two contrasting ecosystems (a broadleaf deciduous forest and a C4 grassland) in a region ...for which cloud cover, meteorological, and isotope data are available for driving the isotope‐enabled land surface model (ISOLSM). Our model results indicate a large impact of clouds on ecosystem CO2 fluxes and isofluxes. Despite lower irradiance on partly cloudy and cloudy days, predicted forest canopy photosynthesis was substantially higher than on clear, sunny days, and the highest carbon uptake was achieved on the cloudiest day. This effect was driven by a large increase in light‐limited shade leaf photosynthesis following an increase in the diffuse fraction of irradiance. Photosynthetic isofluxes, by contrast, were largest on partly cloudy days, as leaf water isotopic composition was only slightly depleted and photosynthesis was enhanced, as compared to adjacent clear‐sky days. On the cloudiest day, the forest exhibited intermediate isofluxes: although photosynthesis was highest on this day, leaf‐to‐atmosphere isofluxes were reduced from a feedback of transpiration on canopy relative humidity and leaf water. Photosynthesis and isofluxes were both reduced in the C4 grass canopy with increasing cloud cover and diffuse fraction as a result of near‐constant light limitation of photosynthesis. These results suggest that some of the unexplained variation in global mean δ18O of CO2 may be driven by large‐scale changes in clouds and aerosols and their impacts on diffuse radiation, photosynthesis, and relative humidity.
To determine leopard Panthera pardus (Linnaeus) food habits in the Lopé National Park in Gabon, Central Africa, 196 leopard scats were collected and analysed. Prey items were determined using ...undigested matter isolated from the scats, and a reference collection of hairs and bones from potential prey species. A minimum of 30 different prey species were identified, 27 of which were mammalian. Leopards preyed mainly on ungulates, which made up 59% of the biomass consumed. Diurnal primates (18%) and large rodents (17%) were also heavily preyed upon. The mean prey weight estimated from scats was 29.2 kg. The most important single prey species was found to be red river hog Potamochoerus porcus (Linnaeus), making up 20% of the biomass consumed, followed by forest buffalo Syncerus caffer nanus (Boddaert) and cane rat Thryonomys swinderianus (Temminck), each comprising 13% of biomass consumed.
Résumé
Afin de déterminer les habitudes alimentaires de la panthère Panthera pardus (Linnaeus) dans le parc national de la Lopé au Gabon (Afrique centrale), 196 excréments ont été collectés et analysés. Des fragments de proies ont été déterminés en utilisant la matière non digérée extraite des excréments et une collection de référence de poils et d'os provenant des espèces de proies potentielles. Un minimum de 30 espèces de proies différentes ont été identifiées, dont 27 appartenaient à la classe des mammifères. Les panthères ont consommé essentiellement des ongulés qui constituaient 59% de la biomasse consommée. Les primates diurnes (18%) et les grands rongeurs (17%) ont aussi été abondamment chassés. Le poids moyen d'une proie, estimée d'après les excréments, était de 29,2 kg. La plus importante espèce de proie était le potamochère Potamochoerus porcus (Linnaeus), constituant 20% de la biomasse consommée, suivi du buffle de forêt Syncerus caffer nanus (Boddaert) et de l'aulacode Thryonomys swinderianus (Temminck), représentant chacun 13% de la biomasse consommée.
Mandrill Mandrillus sphinx hordes in the Lopé Reserve, Gabon, the approximate centre of the mandrill species range, were studied over 3 years from 1996 to 1999. Part of the study site included ...gallery forests within savanna areas, allowing observation of entire hordes, hitherto impossible in dense forest habitat. Horde size and composition (sex and age classes) were documented using exact records on video film whenever a horde or subgroup crossed an open space. Mean horde size was 620, and hordes of up to 845 individuals were documented, probably the largest stable group size found in any wild, unprovisioned primate population. Hordes were cohesive throughout the study period and did not seem to be aggregations of smaller units. Mandrill societies seem to be quite different from the baboon societies, to which they have been compared to date. Mature, breeding-age males were not resident members of hordes, but entered at the onset of seasonal cycles in the females (as deduced by the presence of sexual tumescence) and emigrated once female sexual cycles ceased. The number of breeding males present in the horde at any one time is best explained by the number of sexually attractive females. It is postulated that the extreme coloration of males and strong sexual dimorphism in mandrills may have evolved through an enhanced need for competitive signals in a situation where no long-term social bonds between breeding partners exist.
The decision by the Convention on International Trade in Endangered Species (CITES) to condition a limited sale of ivory on the status of elephant poaching has brought into sharp focus the technical, ...organizational, and financial challenges inherent in setting up a continent-wide monitoring program. The task will be particularly arduous in central Africa, where forest elephant populations are difficult to monitor and the infrastructure necessary for population monitoring is lacking. The magnitude of effort that will be necessary is illustrated by an elephant survey done in the Gamba Complex, a network of protected areas on the southwest coast of Gabon. Implementing the survey required a large-scale program for training Gabonese nationals in field survey and analysis methods necessary for elephant monitoring. Field work carried out during the training program suggests that a combination of reconnaissance and line transects can produce statistically valid population estimates for a substantially lower effort than line transects alone. We illustrate statistical frameworks for comparing the efficiency of alternative sampling methods, and we analyze the sensitivity of current survey methods, which can detect abundance changes on the order of 15%, given fairly high effort levels. Although these training and methodological results are encouraging, they are just small steps in a complex and ongoing process. We argue that this process has many parallels with what needs to be done if the international conservation community is to respond to the challenge set for it by the 1997 CITES meeting. There must be a concerted effort focused both on improving survey methods and on developing the human resources and on-the-ground infrastructure necessary to implement these methods.
► Approaches range from traditional to novel, and from regulatory to academic. ► Established approaches build on assessment push rather than information need pull. ► Four tendencies of development: ...increased engagement, pragmatic framing, multiple benefits & risks, values included.
Environmental health assessment covers a broad area: virtually all systematic analysis to support decision making on issues relevant to environment and health. Consequently, various different approaches have been developed and applied for different needs within the broad field. In this paper we explore the plurality of approaches and attempt to reveal the state-of-the-art in environmental health assessment by characterizing and explicating the similarities and differences between them. A diverse, yet concise, set of approaches to environmental health assessment is analyzed in terms of nine attributes: purpose, problem owner, question, answer, process, use, interaction, performance and establishment. The conclusions of the analysis underline the multitude and complexity of issues in environmental health assessment as well as the variety of perspectives taken to address them. In response to the challenges, a tendency towards developing and applying more inclusive, pragmatic and integrative approaches can be identified. The most interesting aspects of environmental health assessment are found among these emerging approaches: (a) increasing engagement between assessment and management as well as stakeholders, (b) strive for framing assessments according to specific practical policy needs, (c) integration of multiple benefits and risks, as well as (d) explicit incorporation of both scientific facts and value statements in assessment. However, such approaches are yet to become established, and many contemporary mainstream environmental health assessment practices can still be characterized as relatively traditional risk assessment.
Holographic polymer dispersed liquid crystals (HPDLCs) are targeted for application in a wide range of devices as dynamically switchable transmission or reflection diffraction gratings tunable ...through the visible spectra. The inclusion of N-vinyl pyrrolidinone (NVP) has been shown to reduce liquid crystal (LC) droplet size in HPDLC gratings and subsequently improve HPDLC performance. In this work, the influence of NVP on HPDLC polymer/LC morphology is examined and correlated to the influence of NVP on HPDLC photopolymerization kinetics and LC phase separation. As in other photopolymer systems, NVP significantly increases the rate of polymerization in HPDLC photopolymerization. In all the HPDLC formulations studied, NVP is completely incorporated into the polymer network while less than half of acrylate double bonds react. Furthermore, as the highly cross-linked polymer network forms, the small mono-vinyl NVP appears to react preferentially with acrylate double bonds, facilitating additional conversion of pendant double bonds otherwise trapped in the polymer network. NVP also induces a delay in the onset of reaction diffusion termination and extends the range of conversions for which reaction diffusion is observed. Interestingly, NVP also impacts polymer/LC morphology by delaying LC phase separation to higher double bond conversions. Together, the influence of NVP on the polymerization kinetics and LC phase separation alters HPDLC morphology by limiting LC droplet size, consequently resulting in improved HPDLC performance.
This paper presents the first cosmological results based on Planck measurements of the cosmic microwave background (CMB) temperature and lensing-potential power spectra. We find that the Planck ...spectra at high multipoles (ℓ ≳ 40) are extremely well described by the standard spatially-flat six-parameter ΛCDM cosmology with a power-law spectrum of adiabatic scalar perturbations. Within the context of this cosmology, the Planck data determine the cosmological parameters to high precision: the angular size of the sound horizon at recombination, the physical densities of baryons and cold dark matter, and the scalar spectral index are estimated to be θ∗ = (1.04147 ± 0.00062) × 10-2, Ωbh2 = 0.02205 ± 0.00028, Ωch2 = 0.1199 ± 0.0027, and ns = 0.9603 ± 0.0073, respectively(note that in this abstract we quote 68% errors on measured parameters and 95% upper limits on other parameters). For this cosmology, we find a low value of the Hubble constant, H0 = (67.3 ± 1.2) km s-1 Mpc-1, and a high value of the matter density parameter, Ωm = 0.315 ± 0.017. These values are in tension with recent direct measurements of H0 and the magnitude-redshift relation for Type Ia supernovae, but are in excellent agreement with geometrical constraints from baryon acoustic oscillation (BAO) surveys. Including curvature, we find that the Universe is consistent with spatial flatness to percent level precision using Planck CMB data alone. We use high-resolution CMB data together with Planck to provide greater control on extragalactic foreground components in an investigation of extensions to the six-parameter ΛCDM model. We present selected results from a large grid of cosmological models, using a range of additional astrophysical data sets in addition to Planck and high-resolution CMB data. None of these models are favoured over the standard six-parameter ΛCDM cosmology. The deviation of the scalar spectral index from unity isinsensitive to the addition of tensor modes and to changes in the matter content of the Universe. We find an upper limit of r0.002< 0.11 on the tensor-to-scalar ratio. There is no evidence for additional neutrino-like relativistic particles beyond the three families of neutrinos in the standard model. Using BAO and CMB data, we find Neff = 3.30 ± 0.27 for the effective number of relativistic degrees of freedom, and an upper limit of 0.23 eV for the sum of neutrino masses. Our results are in excellent agreement with big bang nucleosynthesis and the standard value of Neff = 3.046. We find no evidence for dynamical dark energy; using BAO and CMB data, the dark energy equation of state parameter is constrained to be w = -1.13-0.10+0.13. We also use the Planck data to set limits on a possible variation of the fine-structure constant, dark matter annihilation and primordial magnetic fields. Despite the success of the six-parameter ΛCDM model in describing the Planck data at high multipoles, we note that this cosmology does not provide a good fit to the temperature power spectrum at low multipoles. The unusual shape of the spectrum in the multipole range 20 ≲ ℓ ≲ 40 was seen previously in the WMAP data and is a real feature of the primordial CMB anisotropies. The poor fit to the spectrum at low multipoles is not of decisive significance, but is an “anomaly” in an otherwise self-consistent analysis of the Planck temperature data.
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