Parikshit Verma

SIMULATING WATER MOVEMENT AND ITS UPTAKE BY PLANT ROOTS IN UNSATURATED ZONES

Existing mathematical models that simulate water movement and contaminant transport in unsaturated zone do not take into account the water uptake by plant crop roots resulting in an error in the prediction of water flux and, thereby, contaminant concentration. Moreover the application of these models is often limited due to the lack of easily accessible and representative soil hydraulic properties, like moisture retention characteristic and unsaturated hydraulic conductivity. In this study, a mathematical model is developed for simulating water movement in unsaturated zones by integrating the one‐dimensional transient unsaturated water flow equation (Richards equation) with a root water extraction term (sink), and also incorporates pedo‐transfer functions (PTF) for estimating soil hydraulic properties. The governing non‐linear partial differential equation is solved numerically by the implicit finite difference method using Picards iterative technique, the formulation has been illustrated by a characteristic example.

Predicting impacts of climate variability on habitats of Hippophae salicifolia (D. Don) (Seabuckthorn) in Central Himalayas: Future challenges

Abstract Climate variability is the most influential driver altering the natural habitats of species leading to worldwide biodiversity loss. Understanding the climatic niche of vulnerable species and predicting its shift due to impending climate change is highly important to assess the damage. It also helps to plan and implement long term ex-situ or in-situ strategies to protect the species and its fragile habitats. Though, various important species of Himalayas are exploited for their economic and medicinal benefits, yet the impact of climate change on species have not been efficiently documented. Present study, is an attempt to understand the impact of climate vulnerability on habitat suitability of Hippophae salicifolia, a multipurpose species that grows particularly on the riparian fronts of river Ganga in Central Himalayas, using species distribution modeling. The Maximum entropy (MaxEnt) model with field observed occurrence locations of the species and CMIP5 (Couple Model Inter-comparison Project) derived bioclimatic variables were used for the study. The predictions were done on the geographic area of Central Himalayas in Uttarakhand state of India according to four IPCC RCPs (Intergovernmental Panel for Climate Change, Representative Concentration Pathways) for the future periods 2050 and 2070. Our results show that the estimated potential (threshold-1) area along the riparian fronts is around 2050 km2 for the current period. Whereas, for the future years, the suitable area is likely to be lost by 87% for all climate change scenarios making H. salicifolia highly vulnerable in it’ s actual habitats. An upward shift in the habitat of the species by 1700 m amsl (2800–4500 m amsl) is also predicted. Shift of species from its micro-habitats due to climate reflects unusual patterns and demands the vital need of applying climate adaptive management for habitat conservation. Present study presents a baseline database for broad-scale applicability of riparian front restoration for species conservation.