PALEONTOLOGY

正20140961 Zhang Linna(Graduate University,Chinese Academy of Sciences,Beijing 100049,China);Fan Junxuan The Applications of Species Distribution Models in Palaeontology(Acta Palaeontologica Sinica,ISSN0001-6616,CN32-1188/Q,52(2),2013,p.146-160,7     

Mapping the stray domestic cat (Felis catus) population in New Zealand: Species distribution modelling with a climate change scenario and implications for protected areas

Species distribution models of stray cats were developed using two types of occurrence data: (i) a combined dataset of stray cats and cat colonies in Auckland and projected to the wider New Zealand area; and (ii) population density as an analogue for country-wide stray cat occurrence. These occurrence data, together with sets of environmental variables were used as input to the Maxent modelling tool to produce maps of suitability for the species. Environmental variables used in the models consist of current bioclimatic conditions, and a future climate scenario (RCP8.5 for year 2070 CCSM model). Commonly occurring bias in the modelling process due to latitude, the area for selecting background points in model evaluation, inherent spatial autocorrelation of occurrence points, and correlated bioclimatic variables were explicitly addressed. Results show that the North Island consistently provide more suitable areas for stray cats with increased suitability in a high emission climate change condition. Key protected areas at risk from the increased suitability to stray cats are also presented.     

Habitat suitability and protection status of four species of amphibians in the Dominican Republic

Hispaniola Island has both a high level of amphibian endemism, and a high level of habitat degradation due to agriculture, infrastructure development, and extractive industries. The objective of this work was to evaluate the capacity of Dominican Republic's current network of protection to maintain the habitat of four species of amphibians endemic to Hispaniola (Osteopilus pulchrilineatus, Osteopilus vastus, Hypsiboas heilprini, and Eleutherodactylus flavescens). Spatial analysis was performed to relate observations of the target species to environmental factors using a maximum entropy algorithm (Maxent). Results of this analysis produced maps of probability of occurrence for each species. Analysis of habitat degradation was based on a change analysis of vegetation, by evaluating trends in the normalized difference vegetation index (NDVI) between 2000 and 2011. Results show that forest loss and species habitat loss within protected areas are smaller but similar to those extracted for the country as a whole, suggesting that the current protected area network is not effective for the maintenance of the habitat of the amphibians analyzed. Enforcement of established protection and restoration within current protected areas could facilitate the protection of up to 25.7% of target amphibian habitat. The methodologies presented here can be applied to measure biodiversity offset effectiveness.     

Slip Rate of Yema River–Daxue Mountain Fault since the Late Pleistocene and Its Implications on the Deformation of the Northeastern Margin of the Tibetan Plateau

The slip rate of Yema River–Daxue Mountain fault in the western segment of Qilian Mountains was determined by the dated offset of river risers or gullies. Results indicate that the left-lateral fault slip rate is 2.82 ± 0.20 mm/a at Dazangdele site,2.00 ± 0.24 mm/a at Shibandun site,and 0.50 ± 0.36 and 2.80 ± 0.33 mm/a at two sites in Zhazihu. The ideal average slip rate of the whole fault is 2.81 ± 0.32 mm/a. The lower slip rate confirms part of the displacement of Altyn Tagh fault was transformed into an uplifting of the strap mountains in the western segment of Qilian Mountains,whereas another part transformed into sinistral displacement of Haiyuan fault. This study illustrates that the slip of large strike-slip faults in the northeastern margin of the plateau transforms into crust thickening at the tip of the fault without large-scale propagation to the outer parts of the plateau.     

Impact of litter quality and soil nutrient availability on leaf decomposition rate in a semi-arid grassland of Northeast China

It was hypothesized that litter with higher N concentration would decompose faster than that with lower N concentration and that increased soil nutrient availability would stimulate litter decomposition. To examine the interspecific differences in decomposition rate of leaf litter in relation with differences in litter chemistry and soil nutrient availability, senescent leaves of four species Pennisetum flaccidum, Artemisia scoparia, Chenopodium acuminatum and Cannabis sativa, and soil samples with different fertilization treatments (no fertilization, N, P, and N + P fertilizations, respectively) were collected from a sandy grassland in Northeast China and incubated under laboratory conditions. The decomposition rate of leaf litter was determined by measuring the CO₂ emission during decomposition of litter. We found remarkable interspecific differences in leaf decomposition rates. Moreover, rates of litter decomposition at different incubation stages were correlated with different litter quality indices. The rate of litter decomposition was positively correlated with initial litter N concentration in the initial stage of the incubation, whereas it was negatively correlated with litter N and P concentrations in the late stage. Responses of litter decomposition to soil nutrient availability differed among species. Our results suggest that both indirect changes in litter quality through shifts of species composition/dominance and direct changes in soil nutrient availability under nutrient addition conditions could affect litter decomposition and consequently C and nutrient cycling of grassland ecosystems.     

Comparing biodiversity between protected savanna and adjacent non-protected farmland in the southern Kalahari

In this study we investigated the effect of different land use options (wildlife versus livestock) on species richness of plants and reptiles in the protected Kgalagadi Transfrontier Park (KTP) versus adjacent non-protected farmland within the same savanna habitat type (Aoub dune veld) in the southern Kalahari, South Africa. Our results show that both plant and reptile species richness as well as plant cover and reptile abundance was significantly higher in the protected KTP than in the non-protected farmland. The higher proportion of shrub but lower proportions of perennial grass cover, herb cover, and herb species richness in the farmland can be explained by higher stocking rates and the differences in feeding behaviour between native wild ungulates (e.g. Antidorcas marsupialis, Oryx gazella) and livestock (mainly sheep). The reptile’s prey availability and microhabitats (perennial grass tussocks and rodent burrows) for thermoregulation and protection against predators were significantly lower in the farmland. To conclude, our results clearly show that long term effects of different land use options (wildlife in protected KTP versus extensive livestock production in the non-protected farmland) even within the same habitat type have led to significant changes in vegetation composition, availability of microhabitat structures and in the reptile community.     

Living on the edge? - On the thermobiology and activity pattern of the large herbivorous desert lizard Uromastyx aegyptia microlepis Blanford, 1875 at Mahazat as-Sayd Protected Area, Saudi Arabia

Field active body temperatures (T_b) and operative temperatures (T_e) were assessed in a population of Uromastyx aegyptia microlepis at Mahazat as-Sayd Protected Area, Saudi Arabia. In summer T_b ranged between 23.2 and 47.2 °C, in winter between 23.0 and 45.1 °C and in spring between 25.5 and 45.9 °C. There is a significant difference between respective T_b and T_e distributions which suggests that U. a. microlepis is an active thermoregulator. Above ground activity is very variable between seasons, with the highest activity level in spring. In winter the animals showed an unimodal activity profile. In spring and summer the lizards exhibit bimodal activity profiles with afternoon activity being generally lower than morning activity levels. Species distribution models were calculated to estimate the future impact of global warming on this taxon. Estimates on the basis of temperature data suggest that the range size on the Arabian Peninsula might be stable but with a remarkable decrease of environmental suitability of up to 70-80%. Based on a synthesis of thermo-ecological data and species distribution models we consider climate warming as a potential threat to the survival of the species.     

Spatial patterns of the soil seed bank and extant vegetation across the dry Minjiang River valley in southwest China

The medium-scale spatial patterns of soil seed banks (SSBs) and extant vegetation and the roles of abiotic factors are poorly understood. We selected the dry Minjiang River valley of southwest China to investigate SSB structure and corresponding extant vegetation in a medium-scale size (200-230 km long, 3-4 km wide) at eight sites across the valley using a germination method and field surveys. We found that, there was low seed density and species number in SSB and less coverage and litter thickness for community in extant vegetation at central sites compared with transitional sites across the dry valley; Quercus spp. occurred frequently in extant vegetation at transitional sites, while Caryopteris spp., Jasminum spp., Rabdosia parvifolia, Sophora davidii, Campylotropis spp., and Bauhinia faberi var. Microphylla was present frequently at central sites; Carex spp. and Artemisia spp. occurred frequently in SSB at transitional sites, while Ajania spp., Poa spp., and Fagopyrum caudatum was present more frequently at central sites. Hierarchical cluster analysis and Kendall’s correlation showed that the spatial variation of both SSB and extant vegetation had significant correlation with rainfall and air evaporation.     

Jurassic granitic magmatism in the lesser Xing’an-Zhangguangcai ranges of NE China: the Dong’an example

ABSTRACT

The ~100,000 km² granitoid belt in the Lesser Xing’an-Zhangguangcai Ranges (LXZR) is an important component of the Phanerozoic granitic provinces (known as the ‘granitoid ocean’) in NE China. To reveal the mechanisms of Mesozoic magmatism and crustal growth in the LXZR, we present systematic geologic data, lithofacies information, zircon U-Pb ages, Hf isotopic, and element geochemical data for the Dong’an granites in the northern LXZR. The results show the following: (1) the Dong’an granites can be subdivided into three lithofacies, namely, medium- to coarse-grained alkali-feldspar granite, fine-grained alkali-feldspar granite, and granitic aplite, which were emplaced during the Early Jurassic (187–178 Ma); (2) the Dong’an granites are characterized by high SiO₂ and total alkali contents and low Fe₂O₃^t contents and Mg# values, and they are enriched in LILEs (e.g., Rb and K) and depleted in HFSEs (e.g., Nb and Ta); and (3) the zircons from these granites yield ε_Hf(t) values of ?2.4 to +5.7 and two-stage model ages of 772–1542 Ma. These results indicate that the Dong’an granites were emplaced during the Early Jurassic, are highly fractionated I-type (HFI) granites and were likely derived from partial melting of the thickened lower crust. Regionally, the Dong’an granites and the Early-Middle Jurassic intrusive rocks (201–163 Ma; 90,000 km²) in the LXZR show a trend of comagmatic evolution controlled by fractional crystallization, and they were successively emplaced during magma evolution. The HFI granites that are geochemically similar to the Dong’an granites formed in the later stage of magma evolution. Combined with regional geological observations, we conclude that the granitic rocks in the LXZR formed in an active continental margin setting related to the subduction of the Paleo-Pacific Plate beneath the Eurasian continent. This process may record an important episode of crustal accretion in the LXZR.     

ICP-MS法测定地球化学样品中痕量金

用电感偶合等离子体质谱法(ICP-MS)测定矿石中痕量金,测定速度快,检出限低,灵敏度高,分析重现性好的特点。方法经国家一级标准物质验证,金的测定结果与标准值相符。