Impacts of Climate Change on Abies spectabilis : an approach integrating a Species Distribution Model (MaxEnt) and a Dynamic Vegetation Model (LPJ-GUESS)

Recent global warming trends, particularly in the arctic regions and Himalayas are modifying forest structure and function, notably biogeographical changes in tree species distribution together with alteration in Net Primary Production (NPP), Leaf Area Index (LAI) and Carbon biomass. These alterations are most pronounced in mountain environments, carrying significant impacts on woody species which are more sensitive to temperature changes. This study was done to elucidate the changes in the suitable habitat area, elevation shift, relative coverage, net primary production and carbon biomass for Abies spectabilis in Manaslu conservation area, Nepal. Being a dominant ecotone species in the Nepal Himalayas, Abies spectabilis is likely to bear the significant climate change impact. This study used future climate scenario output from the CCSM4 climate model (RCP 2.6) in two vegetation modeling approaches - the empirical MaxEnt (Maximum entropy) and process-based LPJ-GUESS (Lund-Postdam-Jena General Ecosystem Simulator). Plant occurrence data were collected through published literatures, online source and from the Herbarium records. Environmental driving data were obtained from the Worldclim- Global Climate Data and from the Royal Netherlands Meteorological Institute (KNMI). The findings show that both the models are in excellent agreement with the current distribution of [i]Abies spectabilis[/i], verified by error rate and Cohen's Kappa. The rate of species movement is predicted to be 14 meters per decade (MaxEnt) and 30 meters of altitude per decade (LPJ-GUESS). in terms of suitable habitat area, MaxEnt predicts reduction of 3 % of the suitable area by the year 2050 while LPJ-GUESS predicts the area to be reduced by 20.5 %. In addition, LPJ-GUESS predicts reducing coverage of [i]Abies spectabilis[/i] from the lower-temperate climatic zone (2000-2500 masl) and increasing coverage in lower-alpine climatic zone (4000-4500 masl) in the coming future. The species will respond to climate warming by increasing its Leaf Area Index, Net Primary Production and Carbon biomass. LPJ-GUESS predicts an increase of 64 (gC m-2 yr-1) mean net primary production by the 2050 scenario (corresponding to a 30.18 % increase relative to modelled current NPP values). Carbon biomass will increase by the mean value of 0.33 (KgCm-2) (corresponding to a 19.87 % increase relative to modelled current cmass values). It is found that annual temperature range and precipitation seasonality (MaxEnt) influence the current distribution while in the future, mean temperature of the coldest quarter will shape the geographical distribution of [i]Abies spectabilis[/i].Climate is changing and it is changing rapidly. Rapidly in the sense that it is changing at a rate - more than we expected. Of-course, the changing patterns is not universally same. Climate is changing at an alarming rate in the Arctic regions and in the Himalayas. In the Himalayas, the warming trend observed ranges from 0.01 to 0.060C/yr. and the annual mean temperature is expected to increase by 2.90C by the middle of the century. The thickness of climate change will bring impacts on socio-economical, biological, physical and other aspects. But here, we are only focused on biological issues; we are interested to know what changes it will bring to plant species? To be more specific, we want to know what changes it will bring to plant species in terms of suitable habitat, elevation shift, relative coverage, net primary production and carbon biomass? For that we choose [i]Abies spectabilis[/i] - as a plant and Manaslu Conservation Area, Nepal – as a location. To set up the climate scenario, we use the data from CCSM4 model. Models used different scenarios to project the future climate states, for this research, we choose RCP 2.6 scenario. RCP stands for Representative Concentration Pathways, which are greenhouse gas concentration trajectories adopted by the IPCC for its fifth assessment report in 2014. 2.6 is a possible range of radiative forcing value in the year 2100 relative to pre-industrial value (i.e an added value of 2.6 W/m2). Plant occurrence data were collected through published literatures, online source and from the Herbarium records. Bioclimatic parameters were calculated according to the local climate. These data were used in two vegetation modeling approaches – the empirical Maxent and process based LPJ-GUESS. Maxent (or Maximum entropy) is a popular software package which based upon the theory of maximum entropy predicts the distribution of a species taking the species presence records and environmental variables as input data. Given data on climate and atmospheric CO2 concentration, LPJ-GUESS estimates the vegetation composition and cover in terms of Plant Functional Types (PFTs), biomass, leaf area index and Net primary Production (NPP). The findings show that both the models are in excellent agreement with the current distribution of [i]Abies spectabilis[/i]. The rate of species movement is predicted to be 14 meters per decade (MaxEnt) and 30 meters of altitude per decade (LPJ-GUESS). In terms of suitable habitat area, MaxEnt predicts reduction of 3 % of the suitable area by the year 2050 while LPJ-GUESS predicts the area to be reduced by 20.5 %. In addition, LPJ-GUESS predicts reducing coverage of [i]Abies spectabilis[/i] from the lower-temperate climatic zone (2000-2500 masl) and increasing coverage in lower-alpine climatic zone (4000-4500 masl) in the coming future. The species will respond to climate warming by increasing its Leaf Area Index, Net Primary Production and Carbon biomass.It is also found that annual temperature range and precipitation seasonality (MaxEnt) influence the current distribution while in the future, mean temperature of the coldest quarter will shape the geographical distribution of [i]Abies spectabilis[/i]

The Rosiglitazone Controversy : The Indian Perspective

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Biodiversity Status, Distribution and Use Pattern of Some Ethno-Medicinal Plants

The erosion of plant biodiversity is a matter of global concern. Due to unawareness the building blocks of entire ecosystems are disappearing. Some medicinal plants like Taxus baccata Linn., Thymus serpyllum Linn., Coleus forskohli Will., Oroxylum indicum Linn., Valeriana hardwickii Wall., Malaxis acuminata D.Don, Habenaria edgeworthii Hook. f.ex.Collett., Costus speciosus (Koen.) Sm., Dioscorea deltodea Wall., Gloriosa superba Linn., Polygonatum cirrhifolium Wall. and Polygonatum verticillatum Linn., Thalictrum foliolosum DC., Berberis aristata DC., Baliospermum montanum Will., Bergenia ciliata (Haworth) Sternb., Clerodendrum serratum Linn., Valeriana jatamansii Jones, Celastrus paniculatus Will., Habenaria intermedeia D. Don, and Curculigo orchioides Gaerth are reached on the border of extinction. The 2008 IUCN Red List shows that the number of threatened plant species is increasing gradually (IUCN 2008). Therefore, there is an immediate need for conservation steps to be taken up along with promotion of conservation of medicinal plants

Stress Relaxation in Aging Soft Colloidal Glasses

We investigate the stress relaxation behavior on the application of step strains to aging aqueous suspensions of the synthetic clay Laponite. The stress exhibits a two-step decay, from which the slow relaxation modes are extracted as functions of the sample ages and applied step strain deformations. Interestingly, the slow time scales that we estimate show a dramatic enhancement with increasing strain amplitudes. We argue that the system ends up exploring the deeper sections of its energy landscape following the application of the step strain.Comment: 13 pages, 5 figure

Superconductivity in 2-2-3 system Y2Ba2Cu2O(8+delta)

Researchers synthesized a new high T(sub c) 2-2-3 superconductor Y2Ba2Cu3O(8+delta) by a special preparation technique and characterized it by ac-susceptibility measurements. Diamagnetism and Meissner effect sets in at low fields and superconducting transition onsets at 90 K. The systematic investigation of the real and imaginary components of ac-susceptibility as a function of temperature and applied ac magnetic field reveals that the magnetic behavior is that of a granular type superconductor

Population Assessment and Threat Categorization of Endangered Medicinal Orchid Malaxis Acuminata D. Don. from North-West Himalaya

Studies on population assessment and threat categorization in selected populations of Malaxis acuminate D. Don., a rare, terrestrial, endangered medicinal orchid of Himalayan region and an important "Astverga" plant were undertaken. Status was determined on site-to-site basis as well as for entire Kumaun region. Based on species occurrence in selected areas, the species were identified as critically endangered to endangered in different sites studied. The results also revealed that natural distribution of the species was narrowing down due to habitat destruction and over exploitation. Immediate remedial measures are needed for the conservation of natural sites to ensure sustainable mode of utilization