Prioritizing areas for conservation and vegetation restoration in post-agricultural landscapes: A Biosphere Reserve plan for Bioko, Equatorial Guinea     

Noelia Zafra-Calvo  Rowena Cerro  Jorge M. Lobo  Sahotra Sarkar 《Biological conservation》2010,143(3):787-794

Although the conversion of natural vegetation to agriculture threatens biodiversity, post-agricultural lands may provide an opportunity to preserve biodiversity if they are allowed to regenerate. We develop a framework for incorporating abandoned agricultural fields into the design of a Biosphere Reserve using former cocoa plantations on Bioko, Equatorial Guinea, as a case study. First, we used BIOCLIM to model the potential distribution of 62 ferns, 327 monocotyledons, 749 dicotyledons, seven primates, and 104 birds on Bioko. Next, we quantitatively assessed the representation of these distributions in conservation areas proposed by the Equatoguinean administration (hereafter “EPAs”). In addition, we used an area prioritization algorithm implemented in the ResNet software package to select an initial set of sites to serve as the Biosphere Reserve’s core areas, that is, intact forest in Bioko’s montane regions. Then, to augment the beta-diversity of the Reserve, we used the area prioritization algorithm to prioritize buffer zones in lowland sites including rainforest remnants and abandoned plantations that have partially regenerated to forest. We also compared the representation of biodiversity in the EPAs to its representation in Biosphere Reserves designed with ResNet. The representation of vegetation types and species in Reserves selected by ResNet that occupy 25% of the land on Bioko is equivalent to the representation achieved by the EPAs, which would cover 42% of Bioko. To conclude, we propose a conservation plan for Bioko.  相似文献   

Effect of Organic and Inorganic Nutrients for Soil Quality Conservation and Yield of Rainfed Low Land Rice in Sub-tropical Plateau Region     

P. Banik  P. K. Ghosal  T. K. Sasmal  S. Bhattacharya  B. K. Sarkar  D. K. Bagchi 《Journal of Agronomy and Crop Science》2006,192(5):331-343

The effect of organic sources of nutrients and inorganic fertilizers, was studied on grain yield of lowland rice and some aspect of soil quality parameters in a field experiment at Agricultural Experimental Farm of Indian Statistical Institute, Giridih, situated at eastern plateau region of India, during consecutive years 1997–2002. Chemical fertilizers and various organic matters were applied to two rice cultivars, Sabita and Subarna. The highest mean grain yield was 3.53 t ha^?1 and maximum agronomic efficiency was 60.3 % with the application of inorganic fertilizer followed by cow dung, where 3.47 t ha^?1 grain yield was recorded with an agronomic efficiency of 57.5 %. Grain yield of rice recorded under organic sources of nutrients was not significantly different from that of inorganic fertilization though there was improvement in soil quality parameters under organic sources. Soil organic carbon (0.72 %), microbial biomass‐C (279.23 μg g^?1 dry soil), urease activity with buffer (33.54 μg urea hydrolyzed g^?1 oven‐dry soil) and non‐buffer (21.97 μg urea hydrolyzed g^?1 of oven‐dry soil) methods and acid phosphatase activity (2.24 μg para‐nitrophenol released g^?1 of oven‐dry soil) analysed following the harvest of the crop were highest under cow dung manure treatment; the most efficient organic source under the experiment. Mean grain yield of rice was significantly higher in Sabita cultivar over Subarna. The regression analyses among the variables have shown that there was linear relationship among soil parameters and grain yield of rice.  相似文献   

Wet-only and bulk deposition studies at New Delhi (India)     

Kulshrestha  U. C.  Sarkar  A. K.  Srivastava  S. S.  Parashar  D. C. 《Water, air, and soil pollution》1995,85(4):2137-2142

Water, Air, & Soil Pollution - Rain water samples were collected at New Delhi during the monsoon of 1994 at a height of 30 m above the ground level using a wet-only collector. Simultaneously,...  相似文献   

A study on short-time sampling of individual rain events at New Delhi during monsoon, 1994     

U. C. Kulshrestha  A. K. Sarkar  S. S. Srivastava  D. C. Parashar 《Water, air, and soil pollution》1995,85(4):2143-2148

Rain water samples of equal volume (50 mL) were collected from two couvective showers at New Delhi on 28 July and 23 August during the monsoon, 1994. The variation of constituents of both the showers showed different trends which might have been due to different antecedent periods. The first shower occurred after an antecedent period of 2–3 hours while the second shower occurred after a 14 day interval. The first shower had acidic pH (<5.6) and relatively higher concentration of NH₄, SO₄, NO₃, Cl, F and K indicating insignificant below cloud scavenging. The second shower had alkaline pH (>5.6) and relatively higher concentrations of Ca and Mg. The higher concentration of Ca and Mg in the second shower were due to the loading with particulate matter during the preceding 14 days which made below cloud scavenging significant.  相似文献   

Effects of combinations of heavy metals on hill activity of Azolla pinnata     

Amar Sarkar  Sasadhar Jana 《Water, air, and soil pollution》1987,35(1-2):141-145

The effects of combinations of Hg, As, Ph, Cu, Cd, and Cr on Hill activity of Azolla pinnata R.Br. were studied. All of the combinations of heavy metals decreased Hill activity of chloroplasts over control values. The effects were most pronounced with the treatments of (Hg + As + Pb + Cu + Cd + Cr), followed by (Hg + As + Pb + Cu + Cd). The degree of inhibition of Hill activity in the species by combinations of heavy metals is less due to antagonistic effects (when 2 or 3 metals in combinations), and is much higher due to synergism (when 4 or more metals in combinations) than that by individual heavy metals tested. The harmful effects of the individual metals were, in general, found by the treatments in the order: Cd > Hg > Cu > As > Pb > Cr.  相似文献   

Bilateral follicular cysts in a water buffalo   总被引：1，自引：1，他引：0  

Khan FA  Nabi SU  Pande M  Das GK  Sarkar M 《Tropical animal health and production》2011,43(3):539-541

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High-throughput approach to detection of knockdown resistance (kdr) mutation in mosquitoes, Culex quinquefasciatus, based on real-time PCR using single-labelled hybridisation probe/melting curve analysis     

Sarkar M  Baruah I  Srivastava RB  Borkotoki A  Bhattacharyya IK 《Pest management science》2011,67(2):156-161

BACKGROUND: Knockdown resistance (kdr) mutation (L1014F) is a well‐defined mechanism of resistance to pyrethroids and DDT in many insect species. Sensitive detection of the mutations associated with resistance is a prerequisite for resistance management strategies. The authors have developed a new real‐time molecular diagnostic assay based on SimpleProbe^®/melting curve analysis for large‐scale kdr genotyping in the wild population of Culex quinquefasciatus Say, the principal vector of bancroftian filariasis. Melting curve analysis is based on the thermal stability difference between matched and mismatched DNA duplexes. The application of SimpleProbe^® chemistry in insects described here is novel in entomology research. RESULTS: The mosquitoes homozygous for knockdown‐resistant and knockdown‐susceptible allele showed melting peaks at 60.45 °C ( ± 0.25) and 64.09 °C ( ± 0.24) respectively. The heterozygous mosquitoes yielded both peaks at approximately 60.5 °C ( ± 0.2) and 64.20 °C ( ± 0.23). Among the 92 samples genotyped, 16 were found to be homozygous resistant, 44 homozygous susceptible and 32 heterozygous. Comparative assessments were made of all the reported methods for kdr genotyping. CONCLUSION: The present method is cheaper, faster, more reliable and versatile than other alternatives proposed in detecting correct kdr genotypes in mosquitoes. This is the first report using a single‐labelled hybridisation probe to detect point mutations in insect populations. Copyright © 2010 Society of Chemical Industry  相似文献   

Distribution of forms of potassium in relation to different agroecological regions of North-Eastern India     

S.K. Reza  Utpal Baruah  T. Chattopadhyay  Dipak Sarkar 《Archives of Agronomy and Soil Science》2013,59(4):507-518

Distribution of potassium (K) in soils is governed by the agroecological region (AERs), as the operational intensity of factors and processes of soil formation vary with AER. Therefore, we aimed at finding out the relationship between the forms of K(K forms) with AER and the association of K forms with soil properties in the North-Eastern region of India. For this, horizon-wise soil samples were collected from pedons, three each from three AERs (15 (hot sub-humid to humid), 16 (warm per-humid) and 17 (warm per-humid with less cool winter)) in the North-Eastern India. The water balance diagram for AER shows that precipitation (P) exceeds the potential evapo-transpiration (PET) from June to October, AER 16 shows almost no period when the PET is more than the P and AER 17 shows that the region experiences only a short water deficit of 100–150 mm during post-monsoon period. Soil samples were analysed for physical and chemical properties and K forms. The soils were acidic to neutral with low cation exchange capacity (CEC). The water-soluble K ranged between 0.006 and 0.144 cmol kg^?1, exchangeable K between 0.07 and 0.54 cmol kg^?1, fixed K from 16.7 to 61.3 cmol kg^?1 and total K from 17.4 to 63.6 cmol kg^?1 in soils of different horizons. Further, the results revealed that all the K forms followed the trend of AER 16 > AER 17 >AER 15. Exchangeable K showed higher correlation with clay (r = 0.519**), while fixed K with organic carbon (r = 0.390*).  相似文献   

Assessment of a sequential extraction procedure for fractionation of soil arsenic in contaminated soils     

AK Ghosh  D Sarkar  DC Nayak  P Bhattacharyya 《Archives of Agronomy and Soil Science》2013,59(6):583-591

A sequential fractionation scheme, based on a soil phosphorous fractionation, was developed to assess the chemical nature, and thus the potential bioavailability and mobility of As, at the sites. Soil As was separated into five fractions with (i) anion exchange resin, (ii) NaHCO₃, (iii) NaOH, (iv) HCl, (v) residual. Most sites contained relatively low concentrations of As in the two most labile fractions. The bulk of the contaminant As at the sites seemed to be associated with soil amorphous Fe and Al minerals and the dominant clay minerals which help in As sorption are montmorillonite and mica. Resin-extractable As in particular might provide a good index of potential As bioavailability and mobility.  相似文献   

Captive breeding of climbing perch Anabas testudineus (Bloch, 1792) with Wova-FH for conservation and aquaculture     

Uttam Kumar Sarkar  Prashant Kumar Deepak  Dhurendra Kapoor  Raje Singh Negi  Samir Kumar Paul  & Sreeprakash Singh 《Aquaculture Research》2005,36(10):941-945

Induced breeding of climbing perch, Anabas testudineus was conducted by synthetic hormone Wova‐FH in the intensity level of 0.1, 0.2 and 0.3 mL kg^?1 of body weight respectively. The brooders were injected one time and left to spawn in the spawning hapa in the sex ratio between male and female as 2:1. It was found that at all the intensity level hormone Wova‐FH could enhance the fishes to breed and lay eggs whereas no breeding was observed in control set. The spawning time, quantity of the brooder spawn, fertilization rate, hatching rate and survival rate were quantified in each set of experiment. The egg output/female was significantly higher in 0.3 mL in comparison with 0.1 and 0.2 mL kg^?1 of body weight. The statistical analysis showed significant (P≤0.05) effect between hormone dose on fertilization rate, egg output and hatching rate. The present experiment suggests that Wova‐FH at the dose of 0.3 mL kg^?1 body weight of fish is more effective which might be considered for raising captive population.  相似文献