Bare Rock Research Articles

Geology is a significant indicator of algal cover and invertebrate species composition on intertidal reefs of Ngari Capes Marine Park, south-western Australia

Effective management of rocky intertidal reefs requires an understanding of spatial variation in species composition and abundance, and the identification of high biodiversity areas. This study identified patterns of invertebrate biodiversity on intertidal reefs of differing underlying structure within Ngari Capes Marine Park, south-west Western Australia. Intertidal reef surveys were conducted at 12 limestone and 9 granite sites throughout the park. Geology was a significant indicator of variation in percentage cover of substrate and invertebrate composition, which covaried with rugosity and complexity. Limestone reefs were characterised by a combination of high and low branching algae and a sand–turf matrix, whereas granite reefs consisted of bare rock. A total of 15772 individual invertebrates representing 10 phyla, 16 classes, 60 families and 121 species was recorded. A high abundance of dove (Family Columbellidae) and jewel top snails (Family Trochidae) characterised limestone reefs, whereas an assortment of limpets and chitons characterised granite reefs. Granite reefs contained more species (92v. 63) and a higher mean (±s.d.) number of individuals (119±58v. 42±79m–2) than did limestone reefs. These findings emphasise the effect of underlying geology on the distribution of intertidal invertebrates and the need for management programs to accommodate different habitat types to effectively conserve biodiversity.

Using deuterium excess, precipitation and runoff data to determine evaporation and transpiration: A case study from the Shawan Test Site, Puding, Guizhou, China

Separating watershed evapotranspiration into its evaporation and transpiration components is important for calculating the carbon that is assimilated by terrestrial vegetation in carbon cycle studies. The key step in this separation is to quantify the evaporation component. The deuterium excess (d-excess) in meteoric water has been shown to be an important indicator of both the original source of the water vapor and the humidity at the vapor source area. It has also shown promise for use in investigating the evaporation losses. While many studies have used the δD/δ18O method to study watershed evaporation, few have discussed the differences between the δD/δ18O (single isotope system) and d-excess (dual isotope system) methods in quantifying watershed evaporation. Given the complexity of natural watersheds, the Shawan Test Site was established at Puding, China, to study the water cycle in five concrete tanks (simulated watersheds) with different land uses over one hydrologic year. There were no plants in two of the tanks (bare rock and bare soil), which allowed verification of evaporation calculations derived from the d-excess and δD/δ18O methods. δD or δ18O values of precipitation in the rainy season, when most of the groundwater recharge occurs, showed great variability. In contrast, the d-excess of the meteoric waters collected during the same rainy season was much more stable than the δD or δ18O values. We quantified the annual evaporative loss of the five watersheds using both methods. Comparison of the results indicated that the d-excess method is more acceptable than the δD/δ18O method due to the stability of d-excess. Calculated ratios of transpiration to evapotranspiration in three tanks planted with vegetation were 56.8% in cultivated land, 70.9% in shrub land, and 85.9% in grassland, demonstrating that in well vegetated watersheds, this component of the cycle is controlled chiefly by plant transpiration. Land use has an important impact on the hydrologic cycle in a watershed, and the d-excess calculations conducted in this study provide new insights for quantifying components of the cycle, especially in the East Asian monsoon region which has rainfall with a large range in δD or δ18O values.

Effect of Covering-Soil Thickness on Crop Growth on Bare Rock and Gravel Land in an Ecological Restoration Project

To study the mechanism by which the thickness of covering soil effects crop growth in an ecological restoration project of bare rock and gravel land, the physiological characteristics of summer maize were observed during 2010–2015. This experiment was set up on exposed rock land, which had been covered by soil with six different thicknesses: 30 (C30), 40 (C40), 50 (C50), 60 (C60), 80 (C80) and 100 cm (C100). During the experiment, soil physical properties and the physiological traits and yields of crops were recorded. The results indicated several effects. 1) With the same thickness level, soil bulk density of the covering soil increased in successive planting years. There was a logarithmic relationship between soil bulk density and covering thickness. There was also a strong algorithmic relationship between covering thickness and sedimentation coefficient (R2=0.91). 2) The thickness of covering soil had a significant influence on both the height of summer maize, and soil and plant analyzer development (SPAD) values. In each treatment, the growth rates of the crops during the jointing and booting stages were higher than that in the booting to grain filling stage. After two years of land-use, the mean height of the crop in the C50 treatment was 8.16%, 3.32%, 3.31%, 9.86% and 7.55% higher than that for the C30, C40, C60, C80 and C100 treatments, respectively. The differences between treatments were significant (p < 0.05). SPAD values were highest at the heading stage. The highest value for the C50 treatment was 298.41 after two years of land-use. 3) Soil thickness significantly affected yields and the water use efficiency (WUE) of summer maize. The highest average crop yield and WUE value during the experimental period for the C50 treatment were 4614.12 kg hm-2 and 13.57 kg hm-2 mm, respectively. For the C50 treatment the multi-year average water use efficiency was significantly higher than that of the other treatments in 2010–2015. In conclusion, a soil thickness of 50 cm covering the bare exposed rock was adequate as a tillage layer for the crop, and all crop growth indexes in this treatment were better than for other soil thicknesses. The results provide a scientific basis for the land remediation and ecological restoration of bare rock and gravel land. At the same time, for Africa, where one-third of the land is desert, arable land resources are relatively scarce and agricultural ecology is fragile, can serve as a significant reference to improve the ecological environment, develop arable land resources and increase agricultural income.

Morphological and ecological adaptation of limpet-shaped top shells (Gastropoda: Trochidae: Fossarininae) to wave-swept rock reef habitats.

Flattening of coiled shells has occurred in several gastropod lineages, while the evolutionary process of shell flattening is little known. The subfamily Fossarininae of the top shell family (Trochidae) is unique, because it includes four genera at various stages of shell flattening. Broderipia and Roya, have zygomorphic shells that has lost coiling, while the sister genera, Fossarina and Synaptocochlea, have respectively turbiniform and auriform shells. Therefore, comparisons of biology, habitats and detailed morphology among these four genera may help us to detect selection pressure driving shell flattening and loss of coiling. Although Broderipia has recently been identified as living symbiotically in the pits of sea urchins, the habitats and biology of the other three Fossarininae species, especially Roya are poorly known. After an extensive search on rocky shores of the Japanese Archipelago, we found live Roya eximia snails on intertidal/subtidal rock surfaces exposed to strong waves. Roya snails crept on the bare rock surface to graze periphyton at low tide, and fled into vacant barnacle shells at high tide. Comparison of the morphology of soft bodies in Fossarininae revealed that the columellar muscle of flattened species has been drastically elongated and arranged in posterior semi-outer edge of the flattened shell as observed in true limpets. The flattering and loss of coiling of the shell in Roya caused acquisition of a zygomorphic flat body, retraction of coiled visceral mass, and expansion of the foot sole. All of these changes improved tolerance against strong waves and the ability to cling to rock surfaces, and thus enabled a lifestyle utilizing both wave-swept rock surfaces and the inside of vacant barnacle shells.

DELINEATION OF ORE OCCURRENCES IN ORE RESERVES APPRAISAL WITH MICROMINE PACKAGE

The ore quality requirements include: cutoff grade, minimum thickness of ore body, maximum permissible thickness of interbeds of barren rocks or offgrade ore within the ore body perimeter, minimum metropercent (metrogram) calculated as the product of cutoff grade and minimum ore body thickness. Recently, mineral reserves appraisal has put in practice automation within specialized programs of geological–surveying data processing. The principal subject in automation of ore occurrence delineation in Micromine package and the topic of this article is delimitation of an ore body across its thickness using the data from the ore quality requirements. This becomes necessary when geological data on external boundaries are absent, which is typical of variable morphology ore bodies: mineralized dikes and zones, ore folds, skarns, ore chimneys, etc. Previously, before this study, Micromine package implemented appraisal of composite material reserves in the following scenarios: along boreholes, by benches, by intervals, by geology, by content. The programmers implemented ,since version 16,the ore occurrence algorithm based on the ore quality requirements using a method in a separate menu tab: Drillhole/ Compositing/ Grade (GKZ).The main kinds (parameters) of the ore occurrence algorithm are the Strictly rules and the Relaxed rules.. The article describes general framework of the analysis of ordinary ore occurrences, and similarity and distinctions in performance of the main kinds of the algorithm. Technically, the ore reserves appraisal based on the ore quality requirements should use the algorithm where all the requirements are maximum possible taken into account. In Micromine package, such algorithm is the Strictly Rules with the option “Do not allow contiguous composites”. Practically, there arises multivariate coupling and delimitation of ore bodies in the identified ore occurrences. The article gives a few somewhat formalized examples to illustrate appropriateness of one or the other method of ore occurrence delineation. Automation of ore reserves appraisal results in essential acceleration of data processing. The described algorithms enable calculation and statistical processing of numerous alternatives of ore occurrences based on the input variables of the ore quality requirements: Cб, Mп, Mр, MC within a short time provided that the data are prepared and clean.

Microorganisms from harsh and extreme environments: a collection of living strains at ACUF (Naples, Italy)

The Algal Collection at the University Federico II (ACUF) is a bioresource center where over 800 live microalgal strains are maintained, mainly belonging to Cyanobacteria, Chlorophyta, Rhodophyta, and Bacillariophyceae. The extremophilic algae maintained at ACUF include thermo-acidophilic and acidotolerant strains, mostly belonging to the Cyanidiophyceae isolated from European and extra-European sites, and also terrestrial isolates from bare rocks and monuments. The main target of the ACUF Center is the study and preservation of the diversity of extremophylic microalgae. This collection is used as a resource for studies about biochemical and evolutionary strategies as well as mechanisms involved in cell functioning under harsh environmental conditions. These organisms can be also useful sources for the production of chemical compounds or other biological products with potential biotechnological applications.

Roof-Inhabiting Cousins of Rock-Inhabiting Fungi: Novel Melanized Microcolonial Fungal Species from Photocatalytically Reactive Subaerial Surfaces.

Subaerial biofilms (SAB) are an important factor in weathering, biofouling, and biodeterioration of bare rocks, building materials, and solar panel surfaces. The realm of SAB is continually widened by modern materials, and the settlers on these exposed solid surfaces always include melanized, stress-tolerant microcolonial ascomycetes. After their first discovery on desert rock surfaces, these melanized chaetothyrialean and dothidealean ascomycetes have been found on Mediterranean monuments after biocidal treatments, Antarctic rocks and solar panels. New man-made modifications of surfaces (e.g., treatment with biocides or photocatalytically active layers) accommodate the exceptional stress-tolerance of microcolonial fungi and thus further select for this well-protected ecological group. Melanized fungal strains were isolated from a microbial community that developed on highly photocatalytic roof tiles after a long-term environmental exposure in a maritime-influenced region in northwestern Germany. Four of the isolated strains are described here as a novel species, Constantinomyces oldenburgensis, based on multilocus ITS, LSU, RPB2 gene phylogeny. Their closest relative is a still-unnamed rock-inhabiting strain TRN431, here described as C. patonensis. Both species cluster in Capnodiales, among typical melanized microcolonial rock fungi from different stress habitats, including Antarctica. These novel strains flourish in hostile conditions of highly oxidizing material surfaces, and shall be used in reference procedures in material testing.

Linking transit times to catchment sensitivity to atmospheric deposition of acidity and nitrogen in mountains of the western United States

AbstractTransit times are hypothesized to influence catchment sensitivity to atmospheric deposition of acidity and nitrogen (N) because they help determine the amount of time available for infiltrating precipitation to interact with catchment soil and biota. Transit time metrics, including fraction of young water (Fyw) and mean transit time (MTT), were calculated for 11 headwater catchments in mountains of the western United States based on differences in the amplitude of the seasonal signal of δ18O in streamflow and precipitation. Results were statistically compared with catchment characteristics to elucidate controlling mechanisms. Transit times also were compared with stream solute concentrations to test the hypothesis that transit times are a primary influence on weathering rates and biological assimilation of atmospherically deposited N. Results indicate that transit times in the study catchments are strongly related to soil, vegetation, and topographic characteristics, with barren terrain (bare rock and talus) and steep slopes linked to high Fyw and short MTT, whereas forest soil (hydrogroup B) was linked to low Fyw and greater MTT. Concentrations of silicate weathering products (Na+ and Si) were negatively related to Fyw and barren terrain, and positively related to MTT and forest soil, supporting the concept that weathering fluxes and buffering capacity tend to be low in alpine areas due to short transit times. Nitrate concentrations were positively related to N deposition, catchment slope, and barren terrain, and negatively related to forest, indicating that hydrologic and/or biogeochemical processes associated with steep slopes limit uptake of atmospherically deposited N by biota. Interannual and seasonal variability in transit times and source water contributions in the study catchments was substantial, reflecting the influence of strong temporal variations in snowmelt inputs in high‐elevation catchments of the western United States. Results from this study confirm that short transit times in these areas are a key reason they are highly sensitive to atmospheric pollution and climate change.

Dependence of Simulation Biases at AHI Surface-Sensitive Channels on Land Surface Emissivity over China

AbstractThis study compares the simulation biases of Advanced Himawari Imager (AHI) brightness temperature to observations made at night over China through the use of three land surface emissivity (LSE) datasets. The University of Wisconsin–Madison High Spectral Resolution Emissivity dataset, the Combined Advanced Spaceborne Thermal Emission and Reflection Radiometer and Moderate Resolution Imaging Spectroradiometer Emissivity database over Land High Spectral Resolution Emissivity dataset, and the International Geosphere–Biosphere Programme (IGBP) infrared LSE module, as well as land skin temperature observations from the National Basic Meteorological Observing stations in China are used as inputs to the Community Radiative Transfer Model. The results suggest that the standard deviations of AHI observations minus background simulations (OMBs) are largely consistent for the three LSE datasets. Also, negative biases of the OMBs of brightness temperature uniformly occur for each of the three datasets. There are no significant differences in OMB biases estimated with the three LSE datasets over cropland and forest surface types for all five AHI surface-sensitive channels. Over the grassland surface type, significant differences (~0.8 K) are found at the 10.4-, 11.2-, and 12.4-μm channels if using the IGBP dataset. Over nonvegetated surface types (e.g., sandy land, gobi, and bare rock), the lack of a monthly variation in IGBP LSE introduces large negative biases for the 3.9- and 8.6-μm channels, which are greater than those from the two other LSE datasets. Thus, improvements in simulating AHI infrared surface-sensitive channels can be made when using spatially and temporally varying LSE estimates.

Assessment of the water and energy budget in a peatland catchment of the Alps using the process based GEOtop hydrological model

Over the millennia, peatlands have sequestered and stored carbon in the form of peat, that today accounts for around 30% of the global soil organic carbon. The peat has formed and accumulated due to the slow decomposition rate of organic matter in waterlogged, anaerobic conditions. The particularly close interdependence of the carbon and water cycles in peatland ecosystems signal the importance of understanding the water cycle to the functioning of peatlands.With this aim, the water and energy cycle of an alpine catchment in Italy, which includes a peatland, was studied using the process-based hydrological model GEOtop and a set of in situ measurements over 4 years (2012–2015). This is a challenging modelling exercise that has not been tried before with GEOtop. The catchment is heterogenous with land covers of peatland, grassland, scree and bare rock in a mountainous area. The GEOtop model was able to replicate the energy and water fluxes measured by an eddy covariance tower located in the peatland as well as the volumetric water content and soil temperature of the peatland accurately over the four years. This study shows that a process-based hydrological model can be used to study the water and energy dynamics of a peatland in a mountainous area.

Using apatite to discriminate synchronous ore-associated and barren granitoid rocks: A case study from the Edong metallogenic district, South China

In order to find criteria to discriminate the synchronous ore-associated and barren granitoid rocks, we have determined apatite chemistry associated with ore-associated (Cu-Au) and barren granitoid rocks in the Edong district of the Middle and Lower Yangtze River metallogenic belt, South China. Both rock types give zircon U-Pb ages between 135.0 and 138.7 Ma. Apatite has a higher volatile and Li content (Cl: 0.19–0.57 wt%, average 0.35 wt%, SO3: 0.08–0.71 wt%, average 0.32 wt%, Li: 0.49–7.99 ppm, average 3.23 ppm) in ore-associated rocks than those in barren rocks (Cl: 0.09–0.31 wt%, average 0.16 wt%, SO3: 0.06–0.28 wt%, average 0.16 wt%, Li: 0.15–0.89 ppm, average 0.36 ppm). Apatite (La/Yb)N ratios and Eu/Eu⁎ values are relatively high and show wider variation in ore-associated rocks than those in barren rocks. Apatite (La/Sm)N and (Yb/Sm)N show positive correlation in ore-associated rocks but negative in barren rocks. The higher volatile content occurs in ore-associated magma, favoring Cu-Au transportation and deposition. Furthermore, amphibole fractional crystallization in ore-associated magma further enriched the ore elements in the residual melt. Barren rocks may have undergone fluid exsolution before emplacement, which makes it barren in Cl, S and ore elements (Cu, S). These signatures emphases the significance of volatile and magma evolution in mineralization and indicate that analyses of magmatic apatite can serve to distinguish ore-associated from barren intrusions.

Magmatic oxygen fugacities of porphyry Mo deposits in the East Xing’an-Mongolian Orogenic Belt (NE China) with metallogenic implications

The East Xing’an–Mongolian Orogenic Belt (EXOB) in China hosts numerous porphyry Mo deposits that are associated with calc-alkaline granitic intrusions. Here we report the trace-element compositions of zircon grains from 11 intrusions collected from 8 porphyry Mo deposits in the EXOB: the superlarge-sized Daheishan and Luming deposits; the large-sized Aolunhua deposit; the medium-sized Kulitu and Yangchang deposits; and the small-sized Erbadi, Hashitu, and Longtoushan deposits. The results show a positive correlation between the Mo tonnage of each deposit and the zircon Ce4+/Ce3+ ratio of the ore-related intrusions. In addition, the Ce4+/Ce3+ ratio of zircon in ore-related intrusions is much higher than that of the associated barren rocks. The Ce4+/Ce3+ ratios of 300, 200 and 100 of zircon seem to separate the intrusions into superlarge-sized, large-sized, medium-sized and small-sized porphyry Mo deposits, respectively. Oxygen fugacity values of ΔFMQ +2 of ore-related intrusions discriminate the medium-sized to superlarge-sized Mo deposits from the small-sized deposits. The relationship between the scale of mineralization and oxygen fugacity suggests that the oxidation condition of the source magma played a critical role in the development of large-sized and superlarge-sized Mo porphyry systems in the EXOB. The zircon Ce4+/Ce3+ ratios of ore-related intrusions of the EXOB are similar to those of porphyry Cu deposits in the Central Asian Orogenic Belt and the Yulong copper belt, but much lower than those of the Chuquicamata porphyry Cu deposit in Chile.

Clusters of deep-sea egg-brooding octopods associated with warm fluid discharge: An ill-fated fragment of a larger, discrete population?

Benthic octopods cluster on bare rock on Dorado Outcrop, a ~3000 m deep basalt exposure. The outcrop hosts intermittent discharge of relatively cool (up to 12.3 °C) hydrothermal fluid that carries about half as much oxygen as bottom seawater (~54 μM vs. 108 μM). We analyzed 231 h of video footage and still images taken by sub-sea vehicles in 2013 and 2014 that documented the clustered octopods, members of the poorly-known genus Muusoctopus. The largest cluster (102 octopods) occurred in a 19 m2 area of fluid discharge, where the basalt was sediment-free; individual octopods were also seen across the outcrop. The clustered octopods appeared to be brooding eggs and a total of 11 egg clutches were confirmed. None of the 186 eggs closely examined showed embryonic development. The intermittent fluid discharge may clear the basalt of sediment and attract gravid octopods which then spawn. However, the increased temperature and limited oxygen of the discharging fluids may threaten the octopods’ survival. Octopods in/near areas of discharging fluid had significantly higher estimated respiration rates (3.1–9.8 contractions/min) than did octopods away from discharging fluid (0.8–6.0 contractions/min). Warm fluids likely increase the octopods’ metabolic rate and thus their oxygen demand but provide only limited oxygen. The resultant physiological stress is hypothesized to eventually kill eggs near fluid discharge. We hypothesize, because these eggs do not survive, the population is sustained by a larger pool of undetectable females that brood their eggs inside cool conduits of this and perhaps other, unstudied basalt outcrops.

Vehicles and Critical Raw Materials: A Sustainability Assessment Using Thermodynamic Rarity

SummaryThe changing material composition of cars represents a challenge for future recycling of end‐of‐life vehicles (ELVs). Particularly, as current recycling targets are based solely on mass, critical metals increasingly used in cars might be lost during recycling processes, due to their small mass compared to bulk metals such as Fe and Al. We investigate a complementary indicator to material value in passenger vehicles based on exergy. The indicator is called thermodynamic rarity and represents the exergy cost (GJ) needed for producing a given material from bare rock to the market. According to our results, the thermodynamic rarity of critical metals used in cars, in most cases, supersedes that of the bulk metals that are the current focus of ELV recycling. While Fe, Al, and Cu account for more than 90% of the car's metal content, they only represent 60% of the total rarity of a car. In contrast, while Mo, Co, Nb, and Ni account for less than 1% of the car's metal content, their contribution to the car's rarity is larger than 7%. Rarity increases with the electrification level due to the greater amount of critical metals used; specifically, due to an increased use of (1) Al alloys are mainly used in the car's body‐in‐white of electric cars for light‐weighting purposes, (2) Cu in car electronics, and (3) Co, Li, Ni, and rare earth metals (La, Nd, and Pr) in Li‐ion and NiMH batteries.

Spread of Antarctic vegetation by the kelp gull: comparison of two maritime Antarctic regions

In the present paper, we compare how the kelp gull, Larus dominicanus, utilizes various nest building materials, particularly vascular plants, bryophytes, lichens and other components, in the Fildes Peninsula area (King George Island) and on the Argentine Islands area. In both areas, nest material primarily consisted of the Antarctic hairgrass (Deschampsia antarctica), bryophytes, lichens, feathers, limpets, and algae. Our study reveals area-specific differences in the utilization of plants for nest building related to local conditions during the nesting season. In the Fildes area, vegetation emerges from under the winter snow cover earlier in the spring, giving the gulls greater choice locally, meaning that the gulls need not resort to long distance material transfer. Here, mosses and lichens dominate in the nest material, likely collected from the nearby vegetation formations. The Antarctic hairgrass in these conditions is mostly found in nests located directly within hairgrass formations. However, on the more southern Argentine Islands, kelp gulls routinely use D. antarctica and some mosses, transferring them from coastal hill tops where snow generally disappears earlier. Here, the gulls appear to be selective still, as they rarely use some mosses, such as Polytrichum strictum, that are abundant near the nesting locations. In the Argentine Islands area, we documented long-range transfer of the Antarctic hairgrass and some other vegetation materials from places of abundance to bare rocks of low islands lacking developed vegetation. This demonstrates the potential of the gulls to serve as dispersal and gene pool exchange agents for the local terrestrial biota in the maritime Antarctic, especially between highly isolated populations from small islands and ice-free areas.

Integration of Vessel-Based Hyperspectral Scanning and 3D-Photogrammetry for Mobile Mapping of Steep Coastal Cliffs in the Arctic

Remote and extreme regions such as in the Arctic remain a challenging ground for geological mapping and mineral exploration. Coastal cliffs are often the only major well-exposed outcrops, but are mostly not observable by air/spaceborne nadir remote sensing sensors. Current outcrop mapping efforts rely on the interpretation of Terrestrial Laser Scanning and oblique photogrammetry, which have inadequate spectral resolution to allow for detection of subtle lithological differences. This study aims to integrate 3D-photogrammetry with vessel-based hyperspectral imaging to complement geological outcrop models with quantitative information regarding mineral variations and thus enables the differentiation of barren rocks from potential economic ore deposits. We propose an innovative workflow based on: (1) the correction of hyperspectral images by eliminating the distortion effects originating from the periodic movements of the vessel; (2) lithological mapping based on spectral information; and (3) accurate 3D integration of spectral products with photogrammetric terrain data. The method is tested using experimental data acquired from near-vertical cliff sections in two parts of Greenland, in Karrat (Central West) and Søndre Strømfjord (South West). Root-Mean-Square Error of (6.7, 8.4) pixels for Karrat and (3.9, 4.5) pixels for Søndre Strømfjord in X and Y directions demonstrate the geometric accuracy of final 3D products and allow a precise mapping of the targets identified using the hyperspectral data contents. This study highlights the potential of using other operational mobile platforms (e.g., unmanned systems) for regional mineral mapping based on horizontal viewing geometry and multi-source and multi-scale data fusion approaches.

Comparing the antipredator behaviour of two sympatric, but not syntopic, Liolaemus lizards

The microhabitat preferences of prey animals can modulate how they perceive predation risk, and therefore, their antipredator behaviour. We tested under standardized conditions how microhabitat preferences of two Liolaemus lizards affected their responses when confronted with two types of ambush predators (raptor vs. snake), under two levels of predation risk (low vs. high). These lizard species are sympatric, but not syntopic; L. chiliensis basks on bushes, a complex microhabitat that may provide protection against visual predators, while L. nitidus prefers open microhabitats, basking on the top of large bare rocks, highly exposed to visual predators. If microhabitat complexity modulates the antipredator response, L. chiliensis may perceive lower predation risk, exhibiting lower intensity of antipredator responses than L. nitidus. Both species reduced their activity after being exposed to both predators, but lizards differed in the assessment of predation risk; L. nitidus reduced its activity independently of the predation risk experienced, while L. chiliensis only reduced its activity in the high-risk condition. The microhabitat preferences shaped during the evolution of these species seem to modulate their perception of predation risk, which may cause interspecific differences in the associated costs of their antipredator responses.

Comparative analysis of winter diets and habitat use by the sympatric blue sheep (Pseudois nayaur) and Alashan red deer (Cervus alashanicus) in the Helan Mountains, China

Abstract. Research that elucidates the differences in the habitat use and diet of sympatric species is essential and meaningful for protection strategies. The habitat use and diet composition of blue sheep (Pseudois nayaur) and Alashan red deer (Cervus alashanicus) in the Helan Mountains, China, were examined from November 2013 to February 2015. Despite the partial overlap in habitat, the habitat used by blue sheep and Alashan red deer were significantly different. Blue sheep preferred mountain woodland steppe with high degree of slope at farther distances from water resources and bare rock. Alashan red deer selected winter habitat in moutain grassland with flat slopes, closer water resources, further distances to human disturbances and bare rock. The diet of blue sheep was significantly different from that of Alashan red deer regarding the proportions of the forage categories. Blue sheep grazed primarily on shrubs (36.7 %) and grass (23.1 %), while the diet of Alashan red deer was dominated by shrubs (43...

Evaluation of potential productivity of woody energy crops on marginal land in China

Energy crops are a basic material in the bioenergy industry, and they can also mitigate carbon emissions and have environmental benefits when planted on marginal lands. The aim of this study was to evaluate the potential productivity of energy crops on marginal lands in China. A mechanistic model, combined with energy crop and land use characteristics, and meteorological and soil parameters, was used to simulate the potential productivity of energy crops. There were three main results. 1) The total marginal land in China was determined to be 104.78 × 106 ha. The 400-mm precipitation boundary line, which is the dividing line between the semi-humid and semi-arid zones in China, also divided the marginal land into shrub land and sparse forest land in the southeast and bare land, bare rock land, and saline alkali land in the northeast. 2) The total area of the marginal land suitable for planting energy crops was determined to be 55.82 × 106 ha, with Xanthoceras sorbifolia and Cerasus humilis mainly grown in the northern China, Jatropha curcas and Cornus wilsoniana mainly grown in the southwest and southeast, and Pistacia chinensis mainly grown in the central area, while also having a northeast-southwest zonal distribution. 3) Taking the highest yield in overlapping areas, the potential productivity of target energy crops was determined to be 32.63 × 106 t/yr. Without considering the overlapping areas, the potential productivity was 6.81 × 106 t/yr from X. sorbifolia, 8.86 × 106 t/yr from C. humilis, 7.18 × 106 t/yr from J. curcas, 9.55 × 106 t/yr from P. chinensis, and 7.78 × 106 t/yr from C. wilsoniana.

Magnetic Parameters of Separation Products and Impurity Aggregates in Concentrates

The changes in separation performance and magnetic characteristics of separation products is traced along the processing circuit of Abagur concentrator at a laboratory scale in order to determine the limit content of magnetite iron in impurity aggregates in the concentrate. The wet magnetic analysis is carried out in the field of H = 175 kA/m, and the magnetic characteristics are determined in the vibration magnetic detector in the field up to 800 kA/m. The concentrate impurity content is governed by the relative content of barren rock and ore aggregates removable in concentration at the given level of the technology.