首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
We surveyed the distribution and status of the long-tailed macaque (Macaca fascicularis umbrosa) in the Nicobar Islands of India. Long-tailed macaques live on 3 islands: Great Nicobar, Little Nicobar and Katchal. There are a total 788 groups. Group size ranged from 25 to 56 individuals with a mean size of 36. Long-tailed macaques are a multimale-multifemale society. Adult males, adult females and immatures constituted 9.7 per cent, 43.2 per cent and 47.1 per cent of the population, respectively. A fairly high ratio of immatures to adult females indicates a healthy population turnover. Vegetation parameters including tree density, canopy cover, canopy height and basal area indicated a still healthful habitats on all the 3 islands. We observed a few threats to the macaques. Measures should be undertaken to ensure survival of the Nicobar subspecies.  相似文献   

2.
Tropical islands are special and sensitive ecosystems which are subjected to various disturbances imposed by human activities and natural disasters. A detailed study about the changing landscape scenarios of these fragile island systems induced by various driving factors could be used for setting up measurements in support of conservation and sustainable development projects. The current research is a meta-analysis of the studies carried out in Andaman and Nicobar islands which analyzed the impact of tsunami of 2004 using geospatial tools. Based on the analysis, it was observed that the Nicobar islands were more affected compared to the Andaman islands. The majority of the researchers used pre- and post-tsunami satellite imagery and adopted visual interpretation method to delineate the changed classes. The study infers uplift of land in Andaman (exposing) and subsidence in Nicobar islands (inundation) with severe damage to the coastal elements like mangroves, coral reefs, plantations and in few cases interior forest. The analysis showed there were no records of the damage for some small islands. Finally, it is concluded that utility of microwave satellite data for change analysis will prove better in regions like Andaman and Nicobar where it is difficult to get cloud free optical data because of the high monsoon periods in these islands. It is also suggested that future work utilizing suitable temporal satellite imagery should focus on the extent of recovery of vegetation and other coastal elements which suffer the impact of disaster.  相似文献   

3.
Though nearly 30% of the Nicobar islands are protected as nature reserves, patterns of endemism have not been considered, resulting in an ineffective protection of the islands. I propose a protected area network for the Nicobar islands based on two criteria. First, I examine the distribution and status of endemic avifauna to prioritize areas for conservation action, based on biological criteria. Second, I examine certain socio-political considerations, and the threats arising from them, and propose a protected area network that will mitigate these threats. On the basis of the distribution of endemic avifauna, I conclude that there are three distinct subgroups, Great Nicobar, Nancowry and Car Nicobar, in the Nicobar islands. Because of the distinctiveness of avifauna assemblages and the similarity in the number of endemics present, each subgroup merits equal conservation attention. The distribution of endemic avifauna indicates that the development of protected areas on Great Nicobar, Camorta and Katchall, and satellite protected areas on Little Nicobar and Nancowry, is necessary for effective protection of the Nicobar islands. The status of the endemic avifauna indicates that the Nancowry subgroup is most urgently in need of conservation action. As the major threat to the Nicobar islands arises from habitat loss due to development activity, there is a need to incorporate all remaining contiguous habitat into protected areas, whereby the islands are adequately safeguarded by legislation from future development threats. I examine the existing protected areas in the Nicobar islands and propose the redesigning of the existing Great Nicobar Biosphere Reserve and the creation of the Nancowry Biosphere Reserve with a view to curtail future habitat loss.  相似文献   

4.
Occurrences of extreme events are likely to cause major decline in global biodiversity. In one such event, on December 26, 2004 tsunami caused extensive damage and irreparable losses to the ecology and biodiversity of low-lying areas of the countries located around the Indian Ocean region. Archipelago of Andaman and Nicobar Islands, one of the richest centre of endemism and biodiversity in the Indo-Malayan region, suffered great loss of forests and coastal biodiversity owing to its closeness to the epicenter of tsunami, i.e. just off the coast of Indonesia. There is little insight into the resilience and rate of recovery pattern of tropical coastal habitats consequent to catastrophic impacts of tsunami. It’s important to study the impacts of tsunami on the forest and biodiversity in order to suggest mitigation, restoration measures and long-term conservation planning. Here we have assessed the immediate after-effects of December 26, 2004 tsunami on the forests and areas prioritized for biodiversity conservation analyzing pre and post tsunami satellite imageries. The effect of topographic patterns of Island’s coastal areas and their distance from the epicenter of tsunami with respect to changes in the forests and different levels of biologically rich areas modeled for prioritization for different groups of Islands in Nicobar has been studied. Great Nicobar accounted for higher proportion of total forest area damaged and submerged in Nicobar, followed by Central Nicobar and Car Nicobar. Mangroves, littoral forest, beach forest and low land swamps and Syzygium swamps were most affected. Study brings out spatially explicit scenario of damaged, submerged and lost forest areas and corresponding area statistics, vital for understanding and mitigating medium and long term effects of tsunami an extreme event.  相似文献   

5.
The palm resources of Andaman & Nicobar Islands are quite rich and unique with a substantial number of endemic species. Andaman & Nicobar Islands, falling within the Indo-Burma region constitute “hottest hotspot” of global biodiversity with an exceptional concentration of endemic species, but are experiencing alarming loss of habitat. The flora and fauna of Andaman group of islands show striking dissimilarities with that of Nicobar group. Palms such as Arenga pinnata, A. westerhoutii, Calamus baratangensis, C. basui, C. longisetus, C. palustris, C. viminalis, Corypha utan, Daemonorops aurea, D. kurziana, D. manii, D. rarispinosa, D. wrightmyoensis, Korthalsia rogersii, Licuala spinosa, Phoenix andamanensis, and Pinanga andamanensis which occur in Andaman groups of islands are absent in the Nicobar group of islands. While Bentinckia nicobarica, Calamus dilaceratus, C. nicobaricus, C. pseudorivalis, C. semierectus, C. unifarius, and Rhopaloblaste augusta are confined to the Nicobars, but seldom found in the Andamans. Areca triandra, Calamus andamanicus, Caryota mitis, Korthalsia laciniosa, Licuala peltata and Pinanga manii are widely distributed in both the group of islands. There is a considerable reduction in their natural population probably due to habitat destruction, low regeneration, and inability to compete with other plants. In addition, calamities like tsunami caused irrecoverable loss of valuable genetic diversity of palms. If conservation efforts are not undertaken, many of the existing species, if not all, are likely to disappear within a foreseeable future. There is dire need for habitat preservation and for in situ conservation. Appropriate conservation strategies should be taken to prevent further genetic erosion of these species and to protect these invaluable plant resources.  相似文献   

6.
Bacillus thuringiensis (Bt) strains were isolated from soil samples of Great Nicobar Islands, one of the “hottest biodiversity hotspots,” where no collection has been characterized previously. The 36 new Bt isolates were obtained from 153 samples analyzed by crystal protein production with light/phase-contrast microscopy, determination of cry gene profile by SDS-PAGE, evaluation of toxicity against Coleopteran, and Lepidopteran insect pests, finally cloning and sequencing. Majority of the isolates showed the presence of 66–35 kDa protein bands on SDS-PAGE while the rest showed >130, 130, 73, and 18 kDa bands. The variations in crystal morphology and mass of crystal protein(s) purified from the isolates of Bt revealed genetic and molecular diversity. Based on the toxicity test, 50 % of isolates were toxic to Ash weevils, 16 % isolates were toxic to cotton bollworm, 38 % isolates were toxic both to ash weevil as well as cotton bollworm, while 11 % of the isolates did not exhibit any toxicity. PCR analysis unveiled prepotency of cry1B- and cry8b-like genes in these isolates. This study appoints the first isolation and characterization of local B. thuringiensis isolates in Great Nicobar Islands. Some of these isolates display toxic potential and, therefore, could be adopted for future applications to control some agriculturally important insect pests in the area of integrated pest management for sustainable agriculture.  相似文献   

7.
8.
Reefs of Andaman and Nicobar Islands harbour 418 species of scleractinian corals spread over an area of 2,000 km2. In April to May, 2010, due to the delayed onset of the southwest monsoon the sea surface temperature of the coastal and oceanic region increased to 31.7 °C in respect to the earlier record of maximum 29.0 °C during the said period. This resulted in mass bleaching of hermatypic corals during May, 2010. Rapid under water surveys have been conducted in reefs of Andaman and Nicobar Islands to assess the health of corals between May 2010 and August 2011. It is estimated that 76.62 ± (SD) 10.83 % of coral species are bleached up to a water depth of 10–15 m. Species from the genus Acropora appeared more susceptible to bleaching than those belong to the genus Porites. During the month of June 2010 the sea surface temperature was reduced to 29 °C perhaps due to the rainfall which stimulated rebuilding of zooxanthellae population in bleached corals. Recovery of 85.54 ± (SD) 6.33 % of bleached corals was seen during the study period of 11 months after the bleaching event. Porites spp. showed a high recovery rate, while Acropora spp. had the highest mortality rate. Coral mortality can have profound ecological and socio-economical implications and highlights the need for sustained monitoring for coral reef conservation in India. Hence, steps must be taken to improve management tools to protect these resources of global significance.  相似文献   

9.
The population of Nicobar is not a single random mating population but divided into a number of subpopulations within each of which essentially random mating takes place. Heterogeneity tests indicate that there is a significant difference among subpopulations for the ABO blood group system but not for the MN system. The overall gene frequencies of the ABO system were: r = 0·914; p = 0·033; q = 0·053. The gene frequencies of the MN system are much more consistent in the area as a whole than in the ABO system. The gene frequencies of the MN system were: M = 0·92 and N = 0·08. The Wahlund's principle yields the value of Ø = 0·0358 for the MN system and the unweighted mean value of Øs equals 0·0301 for the ABO system. The founder effect may have a far greater effect than the effects of chance in the genetical structure of Nicobar subpopulations.  相似文献   

10.
Dendrobium shompenii is described and illustrated as a new species from Great Nicobar Island, India. Affinities with the closely related species Dendrobium nathanielis are discussed.  相似文献   

11.
《Journal of Asia》2014,17(4):761-766
Arboviral infections, viz. dengue and chikungunya are prevalent in the Andaman & Nicobar Islands. During post-tsunami developmental activities, large plastic tanks were provided to the native, Nicobarese tribal households of Car Nicobar Island, to store water for domestic use. These tanks form an ideal breeding source for mosquitoes, especially the vectors of dengue/chikungunya viruses, and few cases of IgM ELISA positives for these infections were identified from this island. In view of this scenario, a survey was carried out to determine the prevalence of these mosquito vectors. Ten randomly selected clusters (neighborhoods with 50 houses each) were surveyed. Each household was inspected for the water holding receptacles. This was the first attempt to determine the prevalence and distribution of the vectors of dengue/chikungunya virus in this Island, against the backdrop of various post tsunami rehabilitation and developmental activities. The stegomyia indices with respect to houses and containers were high during the winter and post-monsoon periods (House Index and Container Index were 69.40 and 46.41 in winter, while 54.40 and 39.49 in post-monsoon). Large plastic tanks (500–1000 l capacity) recorded the highest Breteau Index during all the four seasons. This habitat was observed to support four mosquito species, of which 52% constituted Aedes albopictus. The pupae/person index ranged from 0 to 0.2946. A community-based control approach with multiple stakeholders is envisaged to prevent the vector breeding. This approach would be feasible and effective, with active participation of the tribal chieftain along with village headmen.  相似文献   

12.
Question: How rapidly has the sandy beach and maritime forest vegetation on Phuket recovered and regenerated after the impact of the major Indian Ocean tsunami of 2004? What are the characteristics of sandy beach species for regenerating their populations and the invasion patterns of originally non-sandy beach species or other newcomers after the tsunami? Location: Phuket Island, southern Thailand. Methods: Species composition of beaches was studied on the same research plots 6 months before and 9 months after the tsunami. The changes in individual species cover before and after the tsunami were determined by χ2 tests. Change in community composition was analysed by detrended correspondence analysis. The relationship between species and environmental factors was analysed by canonical correspondence analysis. Results: The sites disturbed by the tsunami were often invaded by annuals, especially grasses and asteraceous plants, rather than by perennials. In contrast, species with clonal growth by stolons decreased significantly. Factors determining the species habitat differences were soil hardness (penetration resistance of sandy soil), per cent silt content, soil water content and beach management. Habitat differences among originally non-sandy beach herbaceous species that expanded their population or moved to the coast after the disaster were defined by sand accretion or erosion caused by the tsunami. Many sandy beach herbaceous communities changed into Dactyloctenium aegyptium communities because of the tsunami were originally constituted by non-sandy beach D. aegyptium with Cenchrus echinatus. Although the forest floors of most maritime forests were invaded by originally non-sandy beach Tridax procumbens, Eleusine indica or D. aegyptium because of the tsunami, this did not result in a change in the vegetation unit, because species' loss was restricted to the understorey. In time, these forests will recover their previous community composition. Conclusions: Our results suggest that originally non-sandy beach native species invaded the disturbed beaches rapidly after the tsunami but their habitats differ. Sites where sand accumulated on a beach because of the tsunami were invaded by D. aegyptium and E. indica, whereas soil erosion permitted invasion by Digitania adscendens. Tridax procumbens establishes rapidly on wet sites with hard soil, high per cent silt content and low beach management pressure. Sandy beach species with subterranean long rhizomes are strongly tolerant of such disasters. We concluded that the species composition of the beaches disturbed by a temporary large disaster is determined by dormancy and growth forms, with radicoid form being influential.  相似文献   

13.
Prioritizing efforts for conserving rare and threatened species with limited past data and lacking population estimates is predicated on robust assessments of their occupancy rates. This is particularly challenging for elusive, long-lived and wide-ranging marine mammals. In this paper we estimate trends in long-term (over 50years) occupancy, persistence and extinction of a vulnerable and data-poor dugong (Dugong dugon) population across multiple seagrass meadows in the Andaman and Nicobar archipelago (India). For this we use hierarchical Bayesian dynamic occupancy models accounting for false negatives (detection probability<1), persistence and extinction, to two datasets: a) fragmentary long-term occurrence records from multiple sources (1959–2004, n = 40 locations), and b) systematic detection/non-detection data from current surveys (2010–2012, n = 57). Dugong occupancy across the archipelago declined by 60% (from 0.45 to 0.18) over the last 20 years and present distribution was largely restricted to sheltered bays and channels with seagrass meadows dominated by Halophila and Halodule sp. Dugongs were not found in patchy meadows with low seagrass cover. In general, seagrass habitat availability was not limiting for dugong occupancy, suggesting that anthropogenic factors such as entanglement in gillnets and direct hunting may have led to local extinction of dugongs from locations where extensive seagrass meadows still thrive. Effective management of these remnant dugong populations will require a multi-pronged approach, involving 1) protection of areas where dugongs still persist, 2) monitoring of seagrass habitats that dugongs could recolonize, 3) reducing gillnet use in areas used by dugongs, and 4) engaging with indigenous/settler communities to reduce impacts of hunting.  相似文献   

14.
This paper deals with the plant folk medicines among Nicobarese aboriginals of Katchal Island, in the Nicobar group, India. The tribals, living in complete geographical isolation, have been using folk medicines from time immemorial. Data on 65 plant species were gathered from experienced old men and women. Therapeutic applications and manner of using are initially documented and described as plant remedies in folkloric tradition and popular domestic medicine. No chemical principles are identified; no putative herbal remedies are pharmaceutically and medically evaluated. A brief account of the geography of the islands, climate, ethnology, and methodology of the present work is given. Vernacular name(s) of the plants in the Nicobarese language are incorporated for the first time in literature.  相似文献   

15.
The larval food plants of the butterflies of the Andaman and Nicobar islands have not been studied, although the butterfly fauna per se is fairly well known. For the first time we report the food plants of the larvae of 120 species of butterflies from these islands on the basis of laboratory rearing and field studies. This information is essential for the formulation of management programmes for butterfly conservation on these islands which are known to harbour critical swallowtail and (possibly) danaine faunas.  相似文献   

16.
Infestation of islands by exotic ants is widespread and increasing due to human activities throughout the world. Exotic ants, particularly the invasive African big-headed ant, Pheidole megacephala (Fabricius), are of great conservation concern for coral cays at the southern end of the Great Barrier Reef, Australia. Little is known, however, about the distribution and ecological impacts of invasive ants in this insular system. We surveyed the ants of 14 vegetated coral cays recording a total of 24 ant species, including at least nine exotics. Pheidole megacephala was by far the most abundant and widespread species, occurring on 11 of 14 islands, often in very large numbers. The inter-island distribution of P. megacephala was best explained by human activities, with frequently visited, and to a lesser degree disturbed islands, more likely to be infested. On large islands (≥?10?ha) P. megacephala exhibited distinct habitat preferences, occurring in significantly lower abundances within heavily-shaded Pisonia grandis forest in the centre of islands, compared to more open, fringing woodland or shrubland. On smaller islands (<10?ha) with less extensive Pisonia stands, P. megacephala penetrated throughout the forest where its abundance was similar to that in open woodland. Despite considerable differences in biotic (floristic composition) and abiotic factors (e.g. island size) as well as the spatial configuration among islands, the severity of infestation by P. megacephala best explained variation in species richness, abundance and assemblage composition of other ants. We suggest a number of strategies to manage P. megacephala infestations on these islands.  相似文献   

17.
This study was undertaken to assess the genetic diversity and host plant races of M. vitrata population in South and Southeast Asia and sub-Saharan Africa. The cytochrome c oxidase subunit 1 (cox1) gene was used to understand the phylogenetic relationship of geographically different M. vitrata population, but previous studies did not include population from Southeast Asia, the probable center of origin for Maruca, and from east Africa. Extensive sampling was done from different host plant species in target countries. Reference populations from Oceania and Latin America were used. An amplicon of 658 bp was produced by polymerase chain reaction, and 64 haplotypes were identified in 686 M. vitrata individuals. Phylogenetic analysis showed no difference among the M. vitrata population from different host plants. However, the results suggested that M. vitrata has formed two putative subspecies (which cannot be differentiated based on morphological characters) in Asia and sub-Saharan Africa, as indicated by the high pairwise FST values (0.44–0.85). The extremely high FST values (≥0.93) of Maruca population in Latin America and Oceania compared to Asian and African population seem to indicate a different species. On the continental or larger geographical region basis, the genetic differentiation is significantly correlated with the geographical distance. In addition, two putative species of Maruca, including M. vitrata occur in Australia, Indonesia and Papua New Guinea. The negative Tajima’s D and Fu’s FS values showed the recent demographic expansion of Maruca population. The haplotype network and Automatic Barcode Gap Discovery analyses confirmed the results of phylogenetic analysis. Thus, this study confirmed the presence of three putative Maruca species, including one in Latin America, one in Oceania (including Indonesia) and M. vitrata in Asia, Africa and Oceania. Hence, the genetic differences in Maruca population should be carefully considered while designing the pest management strategies in different regions.  相似文献   

18.
A new species of wild banana, Musa paramjitiana L. J. Singh, from the Andaman Islands, India is described and illustrated, and its conservation status is assessed. A key to the species of Musa L. from Andaman and Nicobar Islands is also provided.  相似文献   

19.
We describe cranial and mandibular remains of three undescribed individuals of the giant mustelid Megalictis ferox Matthew, 1907 from the latest Arikareean (Ar4), Early Miocene mammal fauna of Nebraska, and Wyoming (USA) housed at the American Museum of Natural History (New York, USA). Our phylogenetic hypothesis indicates that Ar4 specimens assigned to M. ferox constitute a monophyletic group. We assign three additional species previously referred to Paroligobunis to Megalictis: M. simplicidens, M. frazieri, and “M.” petersoni. The node containing these four species of Megalictis and Oligobunis forms the Oligobuninae. We test the hypothesis that Oligobuninae (Megalictis and Oligobunis) is a stem mustelid taxon. Our results indicate that the Oligobuninae form the sister clade to the crown extant mustelids. Based on the cranium, M. ferox is a jaguar-size mustelid and the largest terrestrial mustelid known to have existed. This new material also sheds light on a new ecomorphological interpretation of M. ferox as a bone-crushing durophage (similar to hyenas), rather than a cat-like hypercarnivore, as had been previously described. The relative large size of M. ferox, together with a stout rostrum and mandible made it one of the more powerful predators of the Early Miocene of the Great Plains of North America.  相似文献   

20.
Megachile Latreille is a conspicuous genus of solitary bees distributed worldwide. However, the biology of tropical species is still little known. We present data on biology of Megachile brasiliensis Data Torre, Megachile sejuncta Cockerell and Megachile stilbonotaspis Moure found in two remnants of eastern Amazonian forest in northeastern Brazil. The study was conducted using the trap-nest methodology in two different areas during four periods. We collected a total of 24 nests of M. brasiliensis, 26 of M. sejuncta and 28 of M. stilbonotaspis. The differential abundance of collected nests may reflect the population size in each sampled place. The nesting activity was concentrated mainly between July and January and species presented a multivoltine pattern, except for M. sejuncta, which was partly univoltine. Assessed pollen use showed a predominant use of Attalea sp. (Arecaceae) and, for M. stilbonotaspis, Tylesia sp. and Lepidaploa sp. (Asteraceae). Babassu is a very common palm in the studied areas and the studied species seem to have a strong link with it. We also reported change of pollen use by M. sejuncta, probably due to competition with M. brasiliensis, which may have influenced the biased sex ratio observed in M. sejuncta toward males. Parasites reported here were also recorded for other Megachile species, such as Coelioxys, Brachymeria, Meloidae and Pyralidae species. Mites were observed in association with M. stilbonotaspis. The data presented here set up a background that encourages new studies on the ecology of these three Amazonian species, providing tools for proper biodiversity management and conservation.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号