Introduction. Antarctic ecology: from genes to ecosystems. Part 2. Evolution, diversity and functional ecology

The Antarctic biota has evolved over the last 100 million years in increasingly isolated and cold conditions. As a result, Antarctic species, from micro-organisms to vertebrates, have adapted to life at extremely low temperatures, including changes in the genome, physiology and ecological traits such as life history. Coupled with cycles of glaciation that have promoted speciation in the Antarctic, this has led to a unique biota in terms of biogeography, patterns of species distribution and endemism. Specialization in the Antarctic biota has led to trade-offs in many ecologically important functions and Antarctic species may have a limited capacity to adapt to present climate change. These include the direct effects of changes in environmental parameters and indirect effects of increased competition and predation resulting from altered life histories of Antarctic species and the impacts of invasive species. Ultimately, climate change may alter the responses of Antarctic ecosystems to harvesting from humans. The unique adaptations of Antarctic species mean that they provide unique models of molecular evolution in natural populations. The simplicity of Antarctic communities, especially from terrestrial systems, makes them ideal to investigate the ecological implications of climate change, which are difficult to identify in more complex systems.     

Forest fire in the central Himalaya: climate and recovery of trees

 A forest fire event is influenced by climatic conditions and is supported by accumulation of fuel on forest floor. After forest fire, photosynthetically active solar radiation was reduced due to accumulation of ash and dust particles in atmosphere. Post-fire impacts on Quercus leucotrichophora, Rhododendron arboreum and Lyonia ovalifolia in a broadleaf forest were analysed after a wild fire. Bark depth damage was greatest for L. ovalifolia and least for Q. leucotrichophora. Regeneration of saplings was observed for all the tree species through sprouting. Epicormic recovery was observed for the trees of all the species. Young trees of Q. leucotrichophora (<40 cm circumference at breast height) were susceptible to fire as evident by the lack of sprouting. Under-canopy tree species have a high potential for recovery as evident by greater length and diameter of shoots and numbers of buds and leaves per shoot than canopy species. Leaf area, leaf moisture and specific leaf area were greater in the deciduous species, with few exceptions, than in evergreen species. Received: 26 July 1995 / Revised: 1 March 1996 / Accepted: 9 September 1996     

Vegetation expansion in the subnival Hindu Kush Himalaya

The mountain systems of the Hindu Kush Himalaya (HKH) are changing rapidly due to climatic change, but an overlooked component is the subnival ecosystem (between the treeline and snow line), characterized by short‐stature plants and seasonal snow. Basic information about subnival vegetation distribution and rates of ecosystem change are not known, yet such information is needed to understand relationships between subnival ecology and water/carbon cycles. We show that HKH subnival ecosystems cover five to 15 times the area of permanent glaciers and snow, highlighting their eco‐hydrological importance. Using satellite data from the Landsat 5, 7 and 8 missions, we measured change in the spatial extent of subnival vegetation from 1993 to 2018. The Landsat surface reflectance‐derived Normalized Difference Vegetation Index product was thresholded at 0.1 to indicate the presence/absence of vegetation. Using this product, the strength and direction of time‐series trends in the green pixel fraction were measured within three regions of interest. We controlled for cloud cover, snow cover and evaluated the impact of sensor radiometric differences between Landsat 7 and Landsat 8. Using Google Earth Engine to expedite data processing tasks, we show that there has been a weakly positive increase in the extent of subnival vegetation since 1993. Strongest and most significant trends were found in the height region of 5,000–5,500 m a.s.l. across the HKH extent: R² = .302, Kendall's τ = 0.424, p < .05, but this varied regionally, with height, and according to the sensors included in the time series. Positive trends at lower elevations occurred on steeper slopes whilst at higher elevations, flatter areas exhibited stronger trends. We validated our findings using online photographs. Subnival ecological changes have likely impacted HKH carbon and water cycles with impacts on millions of people living downstream, but the strength and direction of impacts of vegetation expansion remain unknown.     

Neonatal size and infant mortality at high altitude in the western Himalaya

A prospective study was undertaken in Ladakh, India, a high-altitude region of the Himalaya, to investigate the effects of small average birth size on neonatal mortality. While such studies exist from high-altitude regions of the New World and shed light on the adaptive status of high-altitude-dwelling populations there, this is the first to examine this relationship in the Himalaya. In a sample of 168 newborns, birthweight and other anthropometric measurements were reduced relative to Andean and Tibetan newborns. Logistic regression and hazard analysis showed that neonatal biological characteristics such as weight, fatness, and circumferences were important predictors of survival probabilities of infants, especially in the neonatal period. Low Rohrer's Ponderal Index (PI) was particularly strongly related to poor survival outcome. Males and females showed no significant differences in mortality risk. Data derived from reproductive histories revealed that neonatal mortality accounted for 70–80% of total infant mortality in Ladakh. Compared to other high-altitude studies, small newborn size in Ladakh was associated with much higher mortality risks; mortality risk rose dramatically with birthweights below the mean (2,764 grams), which characterized 50% of all newborns. It is argued that newborns in Ladakh are subject to strong directional selective forces that favor higher birthweights that incur lower risks of neonatal mortality, while Andean infants are subject to relatively mild selection pressure at both ends of the birthweight distribution. Given the overall small size at birth of Ladakhi newborns and the poor survival outcomes of newborns below the mean, it is suggested that this population is less well adapted in a biological sense to the stresses inherent in this high-altitude environment than are Andean populations, perhaps due to the relatively recent colonization of the area and the substantial genetic admixture that has occurred in the past. © 1994 Wiley-Liss, Inc.     

Pollination Ecology of Pedicularis punctata Decne. (Scrophulariaceae) in the Kashmir Himalaya

Abstract The pollination ecology of Pedicularis punctata was studied in the Pir Panjal Range of the Kashmir Himalaya in the summer of 1989. Its nectarless, rostrate, long-tubed flower was found to be pollinated exclusively by Bombus foragers vibrating pollen while the stigma contacted pollen in the pollinator's cervical crevice. Workers of Bombus tunicatus and B. flavothoracicus comprised 95% of its pollinators. Pollen-foraging fidelity of its pollinators was greatest where diversity of Bombus -pollinated plant species in three plant communities was least. Foragers on other plants carried virtually no Pedicularis pollen. P. punctata is a mid-season blooming species similar in its pollination syndrome to comparable species in other geographic regions. The enigmatic function of its long, nectarless corolla tube, even more exaggerated in other Asiatic species, requires further investigation.     

Isolation of Pseudomonas corrugata from Sikkim Himalaya

Two isolates of Pseudomonas corrugata, P. corrugata 1, a rhizosphere associate, and P. corrugata 7, a rhizoplane associate have been isolated and characterized from maize soils; these isolates are from the subtropical and temperate regions, respectively in Sikkim Himalaya. The two isolates have been found to be positive for: (i) production of antifungal compounds; (ii) phosphate-solubilizing activity; (iii) nitrogenase activity; and (iv) growth at 4°C under laboratory conditions. These bacteria produce a non-fluorescent yellow pigment, particularly at lower temperature. Both of the isolates seem to be well adapted to temperate conditions.     

The alien flora of Kashmir Himalaya

Compilation of alien flora from phytogeographically distinct regions is of immediate relevance not only for better understanding the patterns of plant invasion but also for explicating the processes promoting invasion at local, regional or global scales. Despite being at higher risk of invasion by plants because of its European colonial past, south Asia has received very little attention in respect of characterization of its alien flora. This paucity of baseline data necessitated compilation of the first catalogue of alien flora from the Kashmir Himalaya—a phytogeographically distinct south Asian region nestled in the northwestern folds of Himalayan biodiversity hotspot. Total alien flora of the region is represented by 571 plant species, belonging to 352 genera and 104 families. It constitutes a relatively higher (29%) proportion of the total flora of the region. Families with largest number of alien representatives are Poaceae (60 species), Asteraceae (54 species), and Brassicaceae (30 species). However, families such as Amaranthaceae (83%) and Chenopodiacae (71%) show higher percentage of aliens relative to their total number of plant species in the region. Most of the alien plant species (38%) trace their origin to Europe, followed by Asia (27%) and Africa (15%). Present study also reports, for the first time, occurrence of seven plant species in this region. Each alien plant species is provided with information on the origin, habit, mode/purpose of introduction, current invasion status, altitudinal range and the primary published source.     

喜马拉雅山脉种子植物多样性特征及分布格局

喜马拉雅山脉是全球著名的生物多样性热点地区之一。该研究对以往收集的喜马拉雅山脉南、北坡植物物种名录及其分布数据进行整合,借助在线数据库对分布数据进行补充与修订,最后整理并汇总了喜马拉雅山脉位于中国、印度、尼泊尔、不丹4国境内的种子植物分布情况,并在此基础上对科属特征、物种组成相似性、区系成分以及海拔梯度上物种分布格局进行分析,为该区域的生物多样性研究以及保护提供数据支撑。结果表明：(1)喜马拉雅山脉共分布有种子植物11 875种,隶属223科2 086属,其中包含7 906种草本植物(66.6%),2 583种灌木(21.8%)和1 386种乔木(11.7%)。(2)研究区涵盖物种数量位于前20的科有菊科(Asteraceae)、兰科(Orchidaceae)、禾本科(Poaceae)、豆科(Fabaceae)、杜鹃花科(Ericaceae)等科,共包含物种7 456种,约占喜马拉雅山脉植物种的62.8%;涵盖物种数量位于前20的属有杜鹃花属(Rhododendron)、报春花属(Primula)、马先蒿属(Pedicularis)、虎耳草属(Saxifraga)、薹草属(Carex)...     

Pollination Ecology of Pedicularis megalantha D. Don (Scrophulariaceae) in the Himachal Himalaya

Abstract In the summer of 1990, the pollination ecology of Pedicularis megalantha was studied in the montane-subalpine spruce-fir forest zone (2750-3050 m) on the north slope of Mt. Huttoo at Narkanda, Himachal Pradesh, in the Indian Himalaya. Its yellow, long-tubed, nectarless flower with a curled rostrum overarched by a broad, inverted lower corolla lip was pollinated exclusively by Bombus albopleuralis and B. tunicatus workers hanging inverted from the corolla and vibrating pollen from introrse anthers concealed within the galea and releasing pollen through a small ventral opening in the galea base. The stigma, protruding from the tip of the rostrum, contacted pollen deposited on the ventral side of the insect's thorax. Corbicular pollen loads from P. megalantha pollinators indicated equal numbers of monolectic and oligolectic foragers. P. megalantha appeared to suffer from competition for pollinators by Cynoglossum wallichii at one site but to be favored in a mixed plant community with nectariferous species offering a forage resource complementary to Pedicularis pollen. As in P. punctata , the long, nectarless corolla tube of P. megalantha appears to function in extending the rostrate vibration pollination mechanism beyond the plant's foliage, which would interfere with its function. It is not an adaptation for nectar-foraging lepidopteran pollinators. P. megalantha was also found to be a root hemiparasite.     

Leaf growth pattern in evergreen and deciduous species of the Central Himalaya,India

Leaf growth patterns were investigated in 11 evergreen (with leaf life-spans of just more than 1 year) and 15 deciduous species, occurring along an elevational gradient of 600–2200 m elevation in the Central Himalaya. Records were made of the leaf initiation period, leaf population dynamics, leaf expansion, leaf mass changes, leaf longevity and related parameters. Species of both groups produced leaves at similar rates during March to April, the driest period of the year. Species of both groups had approximately fully developed foliage during the warm, wet period (mid-June to mid-September) of the monsoon. However, significant differences were found at group level in other characters: shoot length (19.5 cm per shoot for deciduous and 11.7 cm for evergreen species); leaf population per 10 cm shoot length (4.7 vs 15.0); leaf area (107.9 vs 41.4 cm²/ leaf); specific leaf mass (106.9 vs 191.3 g/m²); and leaf mass loss after the monsoon period, being rapid and higher (31.6%) in deciduous species and slow and limited in the evergreens (26.2%). However, species of the two groups showed considerable overlaps in the values of above characters. The evergreen species of the Central Himalaya resembled the deciduous species of the region more than the multi-year leaves of clearly evergreen species. The evergreens bear leaves throughout the year, but like deciduous species bear the cost of annual replacement of old leaves by new leaves. They seem to outcompete deciduous species by producing annually a greater mass of leaves of low-carbon cost (per unit leaf mass), which is capable of conducting photosynthesis all year round. A situation of less marked contrast between favourable and nonfavourable periods, with respect to temperature, seems to favour the leaf characters of the evergreens.     

Covered and naked barleys from the Himalaya

Summary Covered and naked barleys from the Himalaya differ significantly from each other in a multivariate way (Murphy and Witcombe 1986). Two hypotheses which could account for this phenomenon are (1) that the caryopsis covering gene (or a gene closely linked with it) exerts a wide-ranging pleiotropic effect, and (2) that the covered and naked types have evolved to differ with respect to the alleles fixed at many loci. Experimental evidence is presented which supports the latter, an explanation which has implications for our understanding of barley phylogeny and evolution.     

Phenology of high-altitude plants of Kumaun in Central Himalaya,India

The various developmental stages of 184 species of high-altitude plants were studied during 1987 and 1988 in the Pindari glacial moraine area of Kumaun Himalaya in the Central Himalaya. The initiation of growth was synchronised with the beginning of the spring/or summer temperature rise and snowmelt. In this high-altitude zone, the peaks of various phenophases succeeded one after another over about 4 months from early June to October. It is suggested that the plants complete various growth cycles within a very short period of favourable conditions to ensure the survival of their progeny.     

Wild edible plants of the Sikkim Himalaya: Nutritive values of selected species

Wild edible plants form an important constituent of traditional diets in the Himalaya. In the Sikkim Himalaya a total of 190 species have been screened as edible species out of which nearly 47 species come to the market. The present paper deals with nutritive values of 27 most commonly consumed wild edible plants in the Sikkim Himalaya. Of 27 plant species that were analyzed for their nutritive values, 22 were edible for their fruits and five for leaves/shoots. Among different plant parts, generally higher nutrient concentration was recorded for leaves, followed by new shoots and fruits. For different species the crude fiber content ranged between 2.15–39.90%, and the total soluble salts between 4.66–21.00%, and the vitamin C content from 6–286 mg/100 g. The fat content was determined high in the fruits ofCastanopsis hystrix, Machilus edulis, andCinnamomum species, while the protein content was highest inHippophae rhamnoides, Cucumis melo, andEleagnus latifolia. The total carbohydrate content ranged from 32–88% in the fruits of various wild edibles, the reducing sugar from 1.25–12.42%, total sugar from 2.10–25.09%, the lignin content varied from 9.05–39.51%, the hemicellulose between 25.63–55.71% and cellulose content varied from 9.57–33.19% in different species. Among the various macronutrients estimated in the plant samples of different wild edible species, nitrogen was present in highest quantity, followed by potassium, calcium, magnesium, phosphorus, and sodium. Micronutrients, such as iron, zinc, magnesium, and copper contents were analyzed in different plant parts of various wild edible species. The iron content was higher in leaves and new shoots. The nutritive values of certain wild edible species determined in this study are comparable with various commercial fruits. It is suggested that a few wild edible species need to be grown for commercial cultivation and adopted in the traditional agroforestry systems, which will lead to reduced pressure on them in natural forest stands as well as producing economic benefits for poor farmers.     

Compositional and structural features of certain tree stands along an elevational gradient in Central Himalaya

Forests of an elevational transect in the central Himalayan region were studied regarding their tree species composition and structural features. In spite of many differences in compositional and structural features in different forest stands, the arrangement of stands in the ordinations based separately on species composition and structural features exhibit many similarities. Disturbances such as landslides and forest fires play the most important role in the distributor of particular species.     

Growth patterns of early versus late successional multipurpose trees of the western Himalaya

In the mid-western Himalaya (altitude 1350 m, rainfall 1100 mm), multipurpose trees found as escapees in agricultural fields or naturally growing in the forests, play an important role in providing fuel, fooder and small timber to the farmers. Shoot elogation, and tree architecture of 4 year old trees of Grewia optiva, Robinia pseudoacacia and Celtis australis (early successionals), and Quercus leucotrichophora, Q. glauca and Ilex odorata (late successionals), were analyzed. All the late successional species showed a proleptic type of bud and branch production, while the early successional trees made growth through syllepsis. The shoot elongation differed significantly (P <0.05) with the crown position, and ranged from 11 to 30 cm in different species. Early successional species tended to maintain a comparatively narrow crown and showed a significantly (P <0.05) higher ramification ratio, and multilayered canopy. The late successionals, in contrast, showed a wide crown with monolayered canopy, adapted to the weak light intensity. There was only one flush of leaves in Q. leucotrichophora and Q. glauca while in the rest of the species there were two distinct flush periods. The results are important for the management of agroforestry trees.     

Ring widths of Rhododendron shrubs reveal a persistent winter warming in the central Himalaya

Himalayan Mountains provide unique opportunities for the extension of shrub-ring based dendroclimatology beyond the upper tree limit. However, little is known about limiting climate factors of shrub growth under harsh environmental conditions. We established a new ring-width chronology of a Himalayan shrub rhododendron (Rhododendron campanulatum D. Don) at the upper Krummholz treeline in the Mt. Gaurishankar massif, central Himalaya, Nepal. Bootstrapped correlation analysis showed positive relationships between radial growth and temperatures of all months from previous November to current October. Correlations were the highest with winter (December-February) minimum temperature (r = 0.781, p < 0.001), indicating that radial growth of R. campanulatum is strongly sensitive to winter minimum temperature. The linear regression model explained 61 % of the actual winter minimum temperature variance during the calibration period 1960–2013. Periods of low and high minimum winter temperatures in the central Himalaya were consistent with cool and warm episodes found by other regional winter temperature reconstructions from the Himalayas and the Tibetan Plateau. Spatial correlation analysis with land surface temperatures revealed the spatial representativeness of our reconstruction for a larger geographical territory over the Himalayas and the Tibetan Plateau. Furthermore, winter temperature in the central Himalaya is teleconnected with the December-February India-Burma trough. The persistent increasing winter temperature in recent decades in the central Himalaya coincides with continental-scale warming. Alpine vegetation in humid regions of the Himalayas may benefit from winter warming via an earlier start and extension of the growing season, as long as moisture availability is sufficient.     

Recent approach to Buchia biostratigraphy from the Tethyan Himalaya area, China

Recent collections from six sections in Lanongla area,Tethyan Himalaya allow the establishment of four buchia assembles.In ascending they are Buchia-Buchia spitiensis,Buchia masquensis-Buchia rugasa,Buchia blanfordiana,Buchia piochii and Buchia subokensis assemblages.These Buchia assemblages first demonstrate that not only the Upper Jurassic strata but also the highest Buchia assemblage-Buchia subokensis,which appeared in Lower Cretaceous strata all over the world are present in Lanongla area.This first records the highest Buchia assemblage in Lanongla area.