排序方式: 共有25条查询结果,搜索用时 15 毫秒
1.
Ganges River dolphin, Platanista gangetica gangetica, is one of the three obligatory freshwater dolphins in the world and is distributed in the Ganges–Brahmaputra–Meghna and Sangu–Karnaphuli River systems in India, Nepal, and Bangladesh. This species is facing considerable threats to its survival, and its population has dwindled from 4000 to 5000 in the early 1980s to 3500 in 2014 in the distribution range. This article reviews current status of the sub-species, habitat use, and the potential threats that the dolphins face for their survival (details of taxonomic status and genetics, evolutionary adaptations and anatomical peculiarities, physical adaptation, primitive characteristics, biology, behavior, surfacing behavior and dive times, mating and birth, and life span/age have been placed as Electronic Supplementary Materials). Recommendations have been made for the protection and developing strategies for the conservation of this Endangered and endemic sub-species.
Electronic supplementary material
The online version of this article (doi:10.1007/s13280-014-0534-7) contains supplementary material, which is available to authorized users. 相似文献2.
白鱀豚是我国特有的珍稀淡水哺乳动物,仅分布于长江中下游,目前长江白鱀豚的种群数量仅约200头,濒临灭绝。造成白鱀豚濒危的主要威胁来自长江鱼类资源的减少、有害渔具的广泛使用、航运事业的发展、河道的大规模整治、水电工程的建设、水体污染以及白鱀豚自身的生理特征。通过我们多年的研究,提出了建立半自然白鱀豚保护区、人工饲养下白鱀豚的繁殖,和建立长江白鱀豚自然保护区等三大措施。在各级政府和科研部门的共同努力下,三项措施正在落实,为保护白鱀豚创造了良好的条件,但面临的困难还很多,任务十分艰巨,我们希望开展广泛的国际合作,为保护白鱀豚共同努力。 相似文献
3.
Laela S. Sayigh Peter L. Tyack Randall S. Wells Michael D. Scott A. Blair Irvine 《Behavioral ecology and sociobiology》1995,36(3):171-177
Signature whistles of 42 free-ranging bottle-nose dophin calves were compared to those of their mothers. Humans judged their similarity by inspection of spectrograms. There was a sex difference in the tendency of calves to produce whistles similar to or different from those of their mothers; most female calves produced whistles that were different from those of their mothers, whereas male calves were more likely to produce whistles that were similar to those of their mothers. Because matrilineally related females associate together and use signature whistles to establish and/or maintain contact with their calves, there may be a selective pressure for females to produce whistles that are distinct from those of their mothers. There may be fewer constraints governing whistle development in males, with the result that some males produce whistles similar to those of their mothers and others do not. 相似文献
4.
Brooke L. Sargeant Aaron J. Wirsing Michael R. Heithaus Janet Mann 《Behavioral ecology and sociobiology》2007,61(5):679-688
Because behavioral variation within and among populations may result from ecological, social, genetic and phenotypic differences,
identifying the mechanism(s) responsible is challenging. Observational studies typically examine social learning by excluding
ecological and genetic factors, but this approach is insufficient for many complex behaviors associated with substantial environmental
variation. Indian Ocean bottlenose dolphins (Tursiops sp.) in Shark Bay, Western Australia show individual differences in foraging tactics, including possible tool use with marine
sponges and social learning may be responsible for this diversity. However, the contributions of ecological factors to the
development of these foraging tactics were not previously investigated. Here, we determined the relationship between ecological
variables and foraging tactics and assessed whether differences in habitat use could explain individual differences in foraging
tactics. We monitored 14 survey zones to identify how foraging tactics were spatially distributed and matched behavioral data
to the ecological variables within each zone. Three of four foraging tactics were significantly correlated with ecological
characteristics such as seagrass biomass, water depth, presence of marine sponges and season. Further, individual differences
in habitat use were associated with some tactics. However, several tactics overlapped spatially and previous findings suggest
demographic and social factors also contribute to the individual variation in this population. This study illustrates the
importance of environmental heterogeneity in shaping foraging diversity and shows that investigating social learning by ruling
out alternative mechanisms may often be too simplistic, highlighting the need for methods incorporating the relative contributions
of multiple factors. 相似文献
5.
6.
Luciana M. Möller Luciano B. Beheregaray Simon J. Allen Robert G. Harcourt 《Behavioral ecology and sociobiology》2006,61(1):109-117
Kinship has been shown to be an important correlate of group membership and associations among many female mammals. In this study, we investigate association patterns in female Indo-Pacific bottlenose dolphins (Tursiops aduncus) inhabiting an embayment in southeastern Australia. We combine the behavioral data with microsatellite DNA and mitochondrial DNA data to test the hypotheses that genetic relatedness and maternal kinship correlate with associations and social clusters. Mean association between females was not significantly different from a random mean, but the standard deviation was significantly higher than a random standard deviation, indicating the presence of nonrandom associates in the dataset. A neighbor-joining tree, based on the distance of associations between females, identified four main social clusters in the area. Mean genetic relatedness between pairs of frequent female associates was significantly higher than that between pairs of infrequent associates. There was also a significant correlation between mtDNA haplotype sharing and the degree of female association. However, the mean genetic relatedness of female pairs within and between social clusters and the proportion of female pairs with the same and different mtDNA haplotypes within and between clusters were not significantly different. This study demonstrates that kinship correlates with associations among female bottlenose dolphins, but that kinship relations are not necessarily a prerequisite for membership in social clusters. We hypothesize that different forces acting on female bottlenose dolphin sociality appear to promote the formation of flexible groups which include both kin and nonkin. 相似文献
7.
8.
Hooker SK Metcalfe TL Metcalfe CD Angell CM Wilson JY Moore MJ Whitehead H 《Environmental pollution (Barking, Essex : 1987)》2008,152(1):205-216
A small population of endangered northern bottlenose whales (Hyperoodon ampullatus) inhabits "The Gully" a Marine Protected Area on the Scotian Shelf, eastern Canada. Amid concerns regarding nearby oil and gas development, we took 36 skin and blubber biopsy samples in 1996-1997 (prior to major development) and 2002-2003 (five years after development began), and three samples from a population in the Davis Strait, Labrador in 2003. These were analysed for cytochrome P4501A1 (CYP1A1) protein expression (n=36), and for persistent contaminants (n=23). CYP1A1 showed generally low expression in whales from The Gully, but higher levels during 2003, potentially coincident with recorded oil spills, and higher levels in Davis Strait whales. A range of PCB congeners and organochlorine compounds were detected, with concentrations similar to other North Atlantic odontocetes. Concentrations were higher in whales from The Gully than from the Davis Strait, with significant increases in 4,4'-DDE and trans-nonachlor in 2002-2003 relative to 1996-1997. 相似文献
9.
Heidi C. Pearson 《Behavioral ecology and sociobiology》2009,63(10):1437-1446
In societies characterized by a high degree of fission-fusion dynamics, individuals adjust their grouping patterns according
to the shifting balance of costs and benefits associated with grouping. This study examines influences on fission-fusion dynamics
for dusky dolphins (Lagenorhynchus obscurus) in Admiralty Bay, New Zealand. This area is an important foraging habitat for dusky dolphins during the winter and spring.
Admiralty Bay has little predation risk, but nearshore mussel farms may infringe on available habitat. I used generalized
estimating equations to determine the influences of coordinated foraging, predation risk, and presence of mussel farms on
party size, rate of fission-fusion, and behavioral state. I conducted 168 boat-based group focal follows totaling 168 h. The
proportion of individuals observed foraging was positively related to party size and rate of party fusion. Resting had no
effect on party size and did not vary according to location. Near mussel farms, traveling decreased, and rate of party fission
decreased. I conclude that (1) coordinated foraging strategies are a primary influence on fission-fusion dynamics within this
population, (2) dolphins may respond to decreased predation risk by not adjusting party size or location during resting, and
(3) areas near mussel farms are not used for traveling. 相似文献
10.
Rapidly Shifting Baselines in Yangtze Fishing Communities and Local Memory of Extinct Species 总被引:1,自引:0,他引:1
SAMUEL T. TURVEY LEIGH A. BARRETT HAO YUJIANG ZHANG LEI ZHANG XINQIAO WANG XIANYAN HUANG YADONG ZHOU KAIYA TOM HART WANG DING 《Conservation biology》2010,24(3):778-787
Abstract: Local ecological knowledge can provide a unique source of data for conservation, especially in efforts to investigate the status of rare or possibly extinct species, but it is unlikely to remain constant over time. Loss of perspective about past ecological conditions caused by lack of communication between generations may create “shifting baseline syndrome,” in which younger generations are less aware of local species diversity or abundance in the recent past. This phenomenon has been widely discussed, but has rarely been examined quantitatively. We present new evidence of shifting baselines in local perception of regional species declines and on the duration of “community memory” of extinct species on the basis of extensive interviews with fishers in communities across the middle‐lower Yangtze basin. Many Yangtze species have experienced major declines in recent decades, and the Yangtze River dolphin or baiji (Lipotes vexillifer) and Yangtze paddlefish (Psephurus gladius) may have become extinct during the 21st century. Although informants across all age classes were strongly aware of the Yangtze ecosystem's escalating resource depletion and environmental degradation, older informants were more likely to recognize declines in two commercially important fish species, Reeves’ shad (Tenualosa reevesii) and Yangtze pufferfish (Takifugu fasciatus), and to have encountered baiji and paddlefish in the past. Age was also a strong predictor of whether informants had even heard of baiji or paddlefish, with younger informants being substantially less likely to recognize either species. A marked decrease in local knowledge about the Yangtze freshwater megafauna matched the time of major population declines of these species from the 1970s onwards, and paddlefish were already unknown to over 70% of all informants below the age of 40 and to those who first started fishing after 1995. This rapid rate of cultural baseline shift suggests that once even megafaunal species cease to be encountered on a fairly regular basis, they are rapidly forgotten by local communities. 相似文献