Intraspecific cleaning by juvenile Cape white seabream Diplodus capensis (Sparidae) off eastern South Africa

Juveniles of the Cape white seabream Diplodus capensis were observed cleaning adult conspecifics in a large tidepool off Sodwana Bay, South Africa. Although nine other tropical fish species were present and interacted with a nearby pair of Labroides cleaner wrasses, only adults of D. capensis posed for and were cleaned by the D. capensis juveniles. Such cleaning interactions have not been reported previously for this species or among marine fishes off South Africa, and thus add to the growing list of facultative cleaners globally.     

Watershed simulation in a sandy terrain of the Thar desert using GIS

The sandy landscape in a desert contains very few stream channels. This poses a problem for delineating watersheds for analysis. Since large-scale topographical sheets of sandy terrain also contain very little information on height, delineation of watersheds from topographical sheets often becomes difficult. In order to find a simple solution to the problem in the Thar desert of Rajasthan, India, the authors used the well-known ARC/INFO software for simulation of height and drainage network using the scarce topographical information for a sandy terrain near Jodhpur. Superimposition of data layers generated from remote sensing and secondary sources validated the simulation results, and suggested suitability of the method for application in similarly handicapped areas.     

Advanced vegetation indices for sensing paddy growth via hyperspectral measurements

In this study, field-based spectroradiometer measurements were carried out in 72 plots with eight rice varieties along with three nitrogen applications. The critical wavelengths for the studied rice varieties at which the effects of nitrogen applications on spectral reflectance response were found significant, are ρ₅₅₀, ρ₅₆₀, ρ₆₅₅, ρ₇₅₀, ρ₇₅₅, ρ₇₈₀, ρ₈₁₀, ρ₈₄₀, ρ₉₀₀, ρ₉₂₀, ρ₁₀₀₀, ρ₁₀₁₀, ρ₁₀₂₀. Using the critical wavelengths, three derived vegetation indices were compared with established indices (VI and GRI) sensitive to nitrogen. VI₁ and VI₂ were efficiently able to discriminate the level of nitrogen treatments for most of the rice genotypes whereas VI and GRI were unable to find significant difference in nitrogen treatments for rice genotypes except two. Furthermore, nitrogen difference plots exhibited that the paddy crop growth has started earlier with N₃ (150 kg/ha) than N₂ (100 kg/ha) application. Quantitative analysis of rice genotypes revealed that VI₂ can be applied functionally for the assessment of nitrogen stress in rice agriculture system.     

Deformation style in the Munsiari Thrust Zone: a study in the Madlakia–Munsiari–Dhapa section in north-eastern Kumaun Himalaya

The Main Central Thrust demarcates the boundary between the Lesser Himalaya and the Higher Himalaya in the Himalayan orogen. Several definitions of the Main Central Thrust have been proposed since it was originally described as the southern boundary of the crystalline rocks (the Main Central Thrust mass) in the Kumaun-Garhwal Himalaya. The long-held contention that the Munsiari Thrust represents the Main Central Thrust has been negated by recent isotopic studies. One way to define the Main Central Thrust is that it is a ductile shear zone that is delimited by the Munsiari Thrust (MCT-I) in south and the Vaikrita Thrust (MCT-II) in north. The alternative proposition that the Vaikrita Thrust represents the Main Central Thrust is fraught with practical limitations in many parts of the Himalaya, including the study area. In the metamorphic rocks bounded between the Vaikrita Thrust and the Munsiari Thrust, the isoclinal folds of the earliest phase are routinely ascribed to the pre-Himalayan orogeny, whereas all subsequent folding phases are attributed to the Himalayan orogeny. This article elucidates the structural characteristics of the kilometre-thick Munsiari Thrust Zone and revisits the issue of pre-Himalayan orogenic signatures in the thrust zone. With the help of high-resolution field mapping and the analyses of mesoscopic scale structures, we demonstrate that the Munsiari Thrust is a typical fault zone that is made up of a fault core and two damage zones. The fault core traces the boundary between the quartzite and the biotite-gneiss. The damage zones consist of the low-grade metasedimentary rocks in the footwall and the gneiss-migmatite in the hanging wall. The entire fault zone shares an essentially common history of progressive ductile shearing. Successively developed mesoscopic folds trace various stages of progressive ductile shearing in the damage zones. Two recognizable stages of the shearing are represented by the early isoclinal folds and the late kink folds. As the strain during progressive deformation achieved the levels that were too high for accommodation by ductile flow, it was released by development of a tectonic dislocation along a mechanically weak boundary, the Munsiari Thrust. The isoclinal folds and the Munsiari Thrust were developed at different stages of a common progressive deformation during the Himalayan orogeny. Contrary to the popular notion of consistency with respect to orientation, the stretching lineations show large directional variability due to distortion during the late folding.     

Quantitative measurement of arid fluvial processes: Results from an upland catchment in Thar Desert

A quantitative study on fluvial processes was carried out in an upland stream catchment (9.3 ha) near Agolai in the NE of Jodhpur district in the Thar Desert in Rajasthan. The catchment of the studied second order ephemeral channel (1.0–1.4 km long and 1.0–1.5 m deep) has developed on a hill — rocky/gravelly pediment — colluvial plain sequence on rhyolite. Initial results of measurements of channel parameters during two significant runoff generating events of 42 mm and 52 mm in 2007 showed peak discharges of 20 m³s⁻¹ (upstream) and 13 m³s⁻¹ (downstream) that moved sediments (bedload) to distances of 43 m − 141 m in the upstream reach, 6–28 m in the middle reach and 63–95 m in the lower reach. The long profile and cross profile measurements showed a balance between load and discharge through a sequence of alternate deposition and erosion throughout the channel. Hypsometry curves revealed maximum erosion (7.7 cm) in the upper reach and aggradation (2.90 cm) in the lower reach. Cross profile measurements showed bank cuts (6 cm) and vertical incisions (1–2 cm) on the rocky-gravelly V shaped valley in the upper reach, incision (4–30 cm) and localized higher deposition (10–12 cm) in the narrow (<1m) and deep (>1m) U shaped valleys in middle reach and mainly deposition (13 cm) on the wide ( 1–4 m) and shallow channels (0.1 to 0.2 m) in the lower reach.     

Prospecting ground water resources using RS-GIS—A case study from arid western rajasthan of India

In arid regions, inherent climatic conditions and adverse terrain condition pose perpetual shortage of water. The dominant aeolian topography conceals older geological formations making it difficult to infer prospects of ground water and tapping the same. A ground water prospect map has been prepared for a part of Jodhpur district in western Rajasthan through integrated analysis of four major controlling factors: geology, geomorphology, structure and hydrology. Through visual interpretation of satellite data and using Geographical Information System, twenty-five hydro-geomorphic units (prospect units) have been delineated and mapped. Potential of each prospect unit have been discussed in reference to hydro-geomorphic units, their influence and well inventory like well yield, water table level and quality of drinking water. 34 % of the area was classified to have high groundwater potential and 5.8 % area was classified into low potential categories. Most of the area (60.2 %) is of moderate ground water potential.     

Use of Remote Sensing and Geographical Information System in the delineation and characterization of ground water prospect zones

The present study was carried out to delineate and characterize ground water prospect zones using IRS-ID LISS-III geocoded data on 1:50,000 scale. The information on lithology, structure, geomorphology and hydrology were generated and integrated to prepare ground water prospect map for a region in western Rajasthan. The information on nature and type of aquifer, type of wells, depth range, yield range, success rate and sustainability were supplemented to form a good database for identification of favourable zone. Geographical Information system (GIS) was used to prepare database on the above layers, analysis of relationship and integrated map preparation. The study area has a complex geomorphology. The geology is dominated by rocks of post Delhi Intrusive and Quaternary sediments. On the basis of hydrogeology and geomorphic characteristics, four categories of ground water prospect zones: high, moderate, low and very low ere delineated. The high prospect zones are alluvial plains and valley fills mainly influenced by quaternary formations with yield expectation between 100-200 lpm. The moderate zone has pediment surfaces covered by shallow soil cover in addition to weathered and fractured aquifer material with expected yield of water between 50-100 lpm. The low potential zones mainly comprise inselbergs and rocky surface with expected discharge below 50 lpm. The very low prospect zones act as run-off generating zones.     

Vegetation analysis and study of its dynamics in Chandaka Wildlife Sanctuary (Orissa) using aerospace remote sensing

Changes brought in habitat conditions due to increasing human influences on natural areas have posed serious threat to wildlife. Remote Sensing has probably omerged as one of the most viable techniques to assess and monitor habitat conditions. Comparative analysis of maps of two-time period can provide authentic data with respect to changes brought in the habitat conditions. Chandaka Wildlife Sanctuary, covering an area of 213.71 sq. km in Orissa is one of the natural reserves of elephants which has undergone serious changes brought in through anthropogenic activities of urban areas of Cuttack and Bhubaneshwar lying within the proximity of the sanctuary. The natural reserve, an ideal habitat for elephants, was connected to neighbouring extensive forest belts. These connections have been either degraded or deforested over the years. The present study analyses the types of habitat available in the sanctuary using remote sensing data (aerial and satellite). Vegetation-type maps of 1975 have been prepared from B/W aerial photographs of 1:25,000 scale. For assessing the current vegetation types, maps have been prepared from Indian Remote Sensing Satellite (LISS II) false colour composite on 1:50,000 scale. Comparative evaluation of the maps indicates changes in the vegetation pattern, increase in mining and agriculture areas within the sanctuary. Stratified field sampling of vegetation types provide structural characteristics of the vegetation. Bamboo has been found to extend in the valleys and side slopes of the sanctuary area during past 15 years. An analysis on response of vegetation in all major vegetation types mapped have been made in the context of the invasion of Eupatorium odoratum. Finally, bamboo biomass has been assessed through stratified random sampling as it constitutes a major elephant food source.     

Utilizing Geo-information Tools for Mapping Spatio-temporal Changes in Population of <Emphasis Type="Italic">Prosopis cineraria</Emphasis> (khejri) in Agroforestry System of Arid Western Rajasthan

The present study is an attempt to assess the spatial variability and the changes in the population of Prosopis cineraia (khejri) trees in the agroforestry systems of arid part of western Rajasthan. This tree is regarded as an important natural resource for the rural livelihood of desert dwellers because of its multifarious uses. The tree populations were mapped in a geographical information system using available information from aerial photographs, google earth images and IRS-LISS-III satellite images to compare their populations between the past and the very recent period. Mapping carried out in a part of Nagaur district in western part of Rajasthan, indicated increase in khejri trees in the region in 2013–2014 compared to 1960s. The number and tree density were higher under irrigated croplands than under rainfed. Increase in rainfall, multiple uses of the tree, societal and scientific support are the key reasons for the observed changes in their population.     

Multiple forecasts of kharif rice in orissa state-four year experience of fasal pilot study

Considering the requirement of multiple pre-harvest crop forecasts, the concept of Forecasting Agricultural output using Space, Agrometeorology and Land based observations (FASAL) has been formulated. Development of procedure and demonstration of this technique for four in-season forecasts for kharif rice has been carried out as a pilot study in Orissa State since 1998. As the availability of cloud-free optical remote sensing data during kharif season is very poor for Orissa state, multi-date RADARSAT SCANSAR data were used for acreage estimation of kharif rice. Meteorological models have been developed for early assessment of acreage and prediction of yield at mid and late crop growth season. Four in-season forecasts were made during four kharif seasons (1998-2001); the first forecast of zone level rice acreage at the beginning of kharif crop season using meteorological models, second forecast of district level acreage at mid growth season using two-date RADARSAT SCANSAR data and yield using meteorological models, third forecast at late growth season of district level acreage using three-date RADARSAT SCANSAR data and yield using meteorological models and revised forecast incorporating field observations at maturity. The results of multiple forecasts have shown rice acreage estimation and yield prediction with deviation up to 14 and 11 per cent respectively. This study has demonstrated the potential of FASAL concept to provide inseason multiple forecasts using data of remote sensing, meteorology and land based observations.