Identifying priority landscapes for conservation of snow leopards in Pakistan.

Pakistan's total estimated snow leopard habitat is about 80,000 km2 of which about half is considered prime habitat. However, this preliminary demarcation was not always in close agreement with the actual distribution-the discrepancy may be huge at the local and regional level. Recent technological developments like camera trapping and molecular genetics allow for collecting reliable presence records that could be used to construct realistic species distribution based on empirical data and advanced mathematical approaches like MaxEnt. The current study followed this approach to construct an accurate distribution of the species in Pakistan. Moreover, movement corridors, among different landscapes, were also identified through circuit theory. The probability of habitat suitability, generated from 98 presence points and 11 environmental variables, scored the snow leopard's assumed range in Pakistan, from 0 to 0.97. A large portion of the known range represented low-quality habitat, including areas in lower Chitral, Swat, Astore, and Kashmir. Conversely, Khunjerab, Misgar, Chapursan, Qurumber, Broghil, and Central Karakoram represented high-quality habitats. Variables with higher contributions in the MaxEnt model were precipitation during the driest month (34%), annual mean temperature (19.5%), mean diurnal range of temperature (9.8%), annual precipitation (9.4%), and river density (9.2). The model was validated through receiver operating characteristic (ROC) plots and defined thresholds. The average test AUC in Maxent for the replicate runs was 0.933 while the value of AUC by ROC curve calculated at 0.15 threshold was 1.00. These validation tests suggested a good model fit and strong predictive power. The connectivity analysis revealed that the population in the Hindukush landscape appears to be more connected with the population in Afghanistan as compared to other populations in Pakistan. Similarly, the Pamir-Karakoram population is better connected with China and Tajikistan, while the Himalayan population was connected with the population in India. Based on our findings we propose three model landscapes to be considered under the Global Snow Leopard Ecosystem Protection Program (GSLEP) agenda as regional priority areas, to safeguard the future of the snow leopard in Pakistan and the region. These landscapes fall within mountain ranges of the Himalaya, Hindu Kush and Karakoram-Pamir, respectively. We also identified gaps in the existing protected areas network and suggest new protected areas in Chitral and Gilgit-Baltistan to protect critical habitats of snow leopard in Pakistan.

6Li atom percentage determination by atomic absorption-emission spectrometry using a natural lithium hollow cathode lamp.

A simple method has been developed for the determination of 6Li atom % using combined atomic emission-absorption spectrometry employing a commonly available natural lithium hollow cathode lamp. Unlike in previous practice, there is no need for specially fabricated and high cost 6Li and 7Li monoisotopic lamps in this method. The method requires adjustment of total lithium contents of the sample, i.e., 6Li + 7Li, to 2 microg x mL(-1) based upon atomic emission spectroscopy (AES) (C(aes)) against a 2 microg x mL(-1) natural lithium standard. The concentration of the sample was then analyzed by atomic absorption spectroscopy (AAS) measurements (C(aas)). The difference between the concentration measured by AES and AAS, i.e., C(aes)-C(aas), was calculated. The magnitude of the difference was found to be a function of 6Li fraction in the sample. A calibration curve was constructed by plotting 6Li atom % versus [(C(aes)-C(aas))/C(aes)] x 100. 6Li atom % of an unknown sample can be evaluated by putting its [(C(aes)-C(aas))/C(aes)] x 100 value in the calibration curve. The method is fast, convenient, and precise.

Mass spectrometric determination of 234U/238U ratio with improved precision.

A new mass spectrometric method is proposed for measurement of 234U/238U ratio with a single Daly electron multiplier detector using the general peak jump method. The method is based on precise measurement of the 235U/238U ratio and 234U/235U ratio, which are used to calculate the 234U/238U ratio using the equation 234U/238U = 235U/238U x 234U/235U. The results show a significant improvement, i.e., more than 35 times better precision in measuring the (234)U/(238)U ratio with this method (sigma = 2.9 x 10(-8)) as compared to direct measurement of 234U/238U (sigma = 1.1 x 10(-6)). The method widens the applicability of the single collector system, and it will potentially be helpful to improve the precision in the case of the static multicollector system also.