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1.
The annual reproductive cycle of 27 female Mauremys mutica was observed by radiography and ultrasonography from April 2006 to August 2007. Radiography was used to monitor clutch size and ultrasonography was used to monitor changes in the ovarian follicles. The follicles started to enlarge in September and became preovulatory in January. The mean maximum follicle diameter of ovulation was 18.30±1.44 mm, and ovulation occurred from March through August. Eggs were laid between April and August. Turtles entered latent period in early August and the maximum follicular size was at a low of 13.22±2.36 mm in late September. The vitellogenesis of the next reproductive cycle began in October. The 24 adult females laid 56 clutches containing a total of 227 eggs. Average clutch size was 4.05 eggs (range 1–8) and there were 2.33 clutches (range 1–4) per female. Egg shell images were first observed on the sixth or seventh day after ovulation. The oviductal period averaged 6.9 weeks (range 2–16 weeks) on the first clutch, 3.4 weeks (range 2–8 weeks) on the second, and 2.75 weeks (range 2–6 weeks) for the third. Radiography and ultrasonography are non‐invasive and convenient methods to evaluate the reproductive cycle of female M. mutica. They should be applicable to other turtles and should greatly enhance knowledge of reproductive physiology. Zoo Biol 29:50–58, 2010. © 2009 Wiley‐Liss, Inc.  相似文献   

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3.
Loss of habitat and human exploitation have driven many turtle species to the brink of extinction, particularly in many parts of southern Asia. The spiny turtle (Heosemys spinosa) is a terrestrial species distributed throughout the Sundaland region of South‐East Asia. Despite international legislative protection, H. spinosa continues to be illegally collected for the food and traditional medicine markets of China. Given its widespread distribution, taxonomists have reasonably questioned whether H. spinosa truly represents a single evolutionary lineage or multiple undiagnosed species. Recently, a large and illegal shipment of rare, wild‐caught H. spinosa was confiscated in Hong Kong, China, and the turtles were eventually distributed to several zoos and academic collections. Based on analyses of these individuals, along with additional individuals from the pet trade and museum collections, we found concordant genetic and phenotypic variation, indicating that two distinct types of H. spinosa exist in this collection of turtles. Further characterization of this variation will require field surveys and the collection of additional morphological and genetic data from specimens of known geographic provenance. However, our data indicate that this highly exploited, endangered species may contain additional cryptic taxa, and emphasize the critical need for systematic evaluation of species before unrecognized variation is lost forever. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 811–824.  相似文献   

4.
  • 1 This review highlights the status of the European wild rabbit Oryctolagus cuniculus, which is threatened within its native range and yet is a highly successful colonizer across its worldwide, introduced range.
  • 2 The European wild rabbit is a keystone species in Iberia, and the survival of a range of threatened predator species, including the Iberian lynx Lynx pardinus and Spanish imperial eagle Aquila aldabertii, is dependent upon the restoration of rabbit populations. Although not native to the UK, the rabbit also performs significant ecosystem services for nationally rare UK species, by maintaining short sward heights in heathland and grassland ecosystems, and serving as a prey item for populations of predators.
  • 3 We identify the European wild rabbit as an excellent model to demonstrate the wide range of complex effects that an introduced mammalian species may exert on ecosystems to which it has been introduced. These effects include habitat degradation following overgrazing, competition with native mammals and facilitating meso‐predator release and hyperpredation.
  • 4 We also show that rabbit eradication from some sites may generate more problems than are solved because of the impacts of trophic cascades stemming from dependence on rabbits by native predator assemblages.
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5.
From 2005 to 2011, the federally endangered freshwater mussel Epioblasma capsaeformis (oyster mussel) was reintroduced at three sites in the upper Clinch River, Virginia, using four release techniques. These release techniques were (1) translocation of adults (site 1, n = 1418), (2) release of laboratory‐propagated sub‐adults (site 1, n = 2851), (3) release of 8‐week‐old laboratory‐propagated juveniles (site 2, n = 9501), and (4) release of artificially infested host fishes (site 3, n = 1116 host fishes). These restoration efforts provided a unique research opportunity to compare the effectiveness of techniques used to reestablish populations of extirpated and declining species. We evaluated the relative success of these four population restoration approaches via monitoring at each release site (2011–2012) using systematic 0.25‐m2 quadrat sampling to estimate abundance and post‐release survival. Abundances of translocated adult and laboratory‐propagated sub‐adult E. capsaeformis at site 1 ranged 577–645 and 1678–1700 individuals, respectively, signifying successful settlement and high post‐release survival. Two untagged individuals (29.1 and 27.3 mm) were observed, indicating that recruitment is occurring at site 1. No E. capsaeformis were found at sites where 8‐week‐old laboratory‐propagated juveniles (site 2) and artificially infested host fishes (site 3) were released. Our results indicate that translocations of adults and releases of laboratory‐propagated sub‐adults were the most effective population restoration techniques for E. capsaeformis. We recommend that restoration efforts focus on the release of larger (>20 mm) individuals to accelerate augmenting and reintroducing populations and increase the probability for recovery of imperiled mussels.  相似文献   

6.
Orissa, on the east coast of India, is one of the three mass nesting sites in the world for olive ridley turtles (Lepidochelys olivacea). This population is currently under threat as a result of fishery-related mortality; more than 100 000 olive ridleys have been counted dead in the last 10 years in Orissa. In general, the globally distributed olive ridley turtle has received significantly less conservation attention than its congener, the Kemp's ridley turtle (L. kempi), because the latter is recognized as a distinct species consisting of a single endangered population. Our study of mitochondrial DNA haplotypes suggests that the ridley population on the east coast of India is panmictic, but distinct from all other populations including Sri Lanka. About 96% of the Indian population consisted of a distinct 'K' clade with haplotypes not found in any other population. Nested clade analysis and conventional analysis both supported range expansions and/or long-distance colonization from the Indian Ocean clades to other oceanic basins, which suggested that these are the ancestral source for contemporary global populations of olive ridley turtles. These data support the distinctiveness of the Indian Ocean ridleys, suggesting that conservation prioritization should be based on appropriate data and not solely on species designations.  相似文献   

7.
The evolution, taxonomy and conservation of the genus Equuswere investigated by examining the mitochondrial DNA sequences of thecontrol region and 12S rRNA gene. The phylogenetic analysis of thesesequences provides further evidence that the deepest node in thephylogeny of the extant species is a divergence between twolineages; one leading to the ancestor of modern horses (E.ferus, domestic and przewalskii) and the other to thezebra and ass ancestor, with the later speciation events of the zebrasand asses occurring either as one or more rapid radiations, or withextensive secondary contact after speciation. Examination of the geneticdiversity within species suggested that two of the E. hemionussubspecies (E. h. onager and E. h. kulan) onlyrecently diverged, and perhaps, are insufficiently different to beclassified as separate subspecies. The genetic divergence betweendomestic and wild forms of E. ferus (horse) and E.africanus (African ass) was no greater than expected within anequid species. In E. burchelli (plains zebra) there was anindication of mtDNA divergence between populations increasing withdistance. The implications of these results for equid conservation arediscussed and recommendations are made for conservation action.  相似文献   

8.
Nilgirianthus ciliatus is a globally endangered aromatic slender shrub of Western Ghats with extensive applications in Ayurveda. It is endangered due to its indiscriminate collection and overexploitation to meet the requirements of the pharmaceuticals. This study deals with the preservation of this endangered plant through in vitro nodal culture. Nodal explants were initially cultured on Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine (BA) or 6-furfurylaminopurine individually for primary shoot induction. For multiple shoot induction, primary shoots were transferred onto MS medium containing BA individually or in combination with auxins. Clusters of multiple shoots (up to 24.3) occurred with highest frequency (93.2%) on MS medium fortified with BA (3 mg l?1) and indole-3-acetic acid (0.1 mg l?1). In vitro regenerated plantlets were rooted on half-strength MS medium with maximum rooting frequency (82.2%) obtained in the presence of indole-3-butyric acid (1.0 mg l?1). The rooted plantlets were acclimatized to soil with 100% survival rate. Results of this study allowed us to develop an efficient regeneration system that will permit to carry out restoration programmes of N. ciliatus in Western Ghats. In future, this protocol will be an invaluable tool to produce synthetic seeds for cryopreservation and long-term conservation.  相似文献   

9.
Cold‐adapted species are thought to have had their largest distribution ranges in central Europe during the glacial periods. Postglacial warming caused severe range shifts of such taxa into higher latitudes and altitudes. We selected the boreomontane butterfly Lycaena helle (Denis & Schiffermüller, 1775) as an example to demonstrate the genetic effects of range changes, and to document the recent status of highly fragmented remnant populations. We analysed five polymorphic microsatellite loci in 1059 individuals sampled at 50 different localities scattered over the European distribution area of the species. Genetic differentiation was strong among the mountain ranges of western Europe, but we did not detect similarly distinct genetic groups following a geographical pattern in the more eastern areas. The Fennoscandian populations form a separate genetic group, and provide evidence for a colonization from southern Finland via northern Scandinavia to south‐central Sweden. Species distribution modelling suggests a large extension of the spatial distribution during the last glacial maximum, but highlights strong retractions to a few mountain areas under current conditions. These findings, combined with our genetic data, suggest a more or less continuous distribution of L. helle throughout central Europe at the end of the last ice age. As a consequence of postglacial warming, the species retreated northwards to Fennoscandia and escaped increasing temperatures through altitudinal shifts. Therefore, the species is today restricted to population remnants located at the mountain tops of western Europe, genetically isolated from each other, and evolved into genetically unique entities. Rising temperatures and advancing habitat destruction threaten this wealth of biodiversity. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 155–168.  相似文献   

10.
1. One important goal in conservation biology is to characterise evolutionary lineages within endangered species before management decisions are taken. Here, we assess population differentiation in the freshwater crayfish Austropotamobius pallipes, an endangered species endemic to western Europe and provide valuable information for the conservation of French populations. 2. Analysis of five microsatellite loci in 44 populations revealed very different within population levels of genetic diversity (0.000 < H0 < 0.564). Two groups, corresponding to northern and southern French populations, showed a high degree of genetic differentiation in both allele frequencies and allele sizes. Comparison of these results with previous studies of A. pallipes strongly suggests that the divergence between northern and southern populations could have occurred during the last glaciation period of the Pleistocene from one Atlantic and one Mediterranean refuge. 3. Evidence for genetic admixture between these two lineages was revealed by correspondence analyses in southern populations, probably as the result of artificial translocations. 4. French populations appeared significantly differentiated among the different river drainages and were highly structured within rivers. The impact of population size, population bottlenecks and founder events on the population genetic differentiation are discussed. 5. Based on these results, we propose the designation of two evolutionarily significant units for A. pallipes in France. Our data also support the maintenance of separate demographic management strategies for crayfish inhabiting different river systems. However, genetic analyses will have to be combined with demographic and ecological data for sustainable conservation programmes.  相似文献   

11.
The diversity and genetic structure of the cycad Dioon sonorense (De Luca, Sabato & Vázq. Torres) Chemnick, T.J. Greg. & S. Salas-Mor. were evaluated from the four known populations in tropical dry forests of Sonora, Mexico. The estimates of genetic diversity in the 19 loci analysed were: mean number of alleles per locus (A = 2.0), percentage of polymorphic loci (P = 81.6) and expected heterozygosity (HE = 0.314). The subpopulations were found to be in Hardy–Weinberg equilibrium at the local level (Fis), even though we found a global excess of homozygotes (Fit = 0.13). Genetic variation attributed to differences among populations was 15%. Our results indicate that the geographical isolation caused by the historical effects of the Pleistocene among populations has probably generated clinal variation of the allelic frequencies at two loci, in relation to their latitudinal distribution. We compare our results with the long-lived southern hemisphere trees Fitzroya and Nothofagus in relationship to the Pleistocene glaciations. We also infer that the populations have become fragmented recently due to increasing pressure of habitat conversion, disturbance and illegal extraction of plants and seeds for the international horticultural trade. We therefore recommend three aspects: (i) propagation of this species for reintroduction, (ii) declare the localities of its northern distribution as a protected area, and (iii) an amendment of the current International Union for Conservation of Nature Red List categorisation for this species to ‘Critically Endangered’.  相似文献   

12.
As anthropogenic activity makes deeper incursions into forests, fragmenting habitat, wildlife is forced into closer proximity to humans leading to increased incidences of human–wildlife conflict and wildlife displacement. These same incursions facilitate poaching for the commercial trade in dead and live animals. As a direct result, the number of sanctuaries and internally displaced animals (IDAs) in need of sanctuary placement and rehabilitation are increasing. We focus on internally displaced primates given the prevalence of primate‐focused facilities and anthropomorphic considerations surrounding this taxonomic group. Surveys were distributed globally to map the extent and range of native primate sanctuaries and species. Over 70 facilities care for more than 6,000 native primates comprising 64 species, with almost half listed as endangered or critically endangered. As not all sanctuaries were identified at the time of the survey distribution, we estimate that the actual number of facilities is closer to double this number with a captive population in excess of 10,000 individual primates. Native primate sanctuaries hold significant numbers of primates in long‐term captive care, with less than half (37%) identified as candidates for release. The surveyed sanctuary population accounts for 35% of the world's captive primates, as compared to ISIS‐registered (where ISIS is International Species Information System) zoological facilities, although we estimate that the actual population is closer to 58%. For some species, the sanctuary population represents the only population in captivity. We discuss the prevalence of range‐state sanctuaries and their primate populations, and issues surrounding their future development and management. Am. J. Primatol. 75:116‐134, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   

13.
Some fundamental natural-history traits of the endangered mud snail Cerithidea rhizophorarum were investigated for three years in an open, bare, sandy tidal flat located on the east of Shikoku Island in southwestern Japan. Our study demonstrated a highly aggregated distribution of younger snails and complicated differences in vertical migration patterns between younger and older snails that might have prevented comprehensive understanding of the precise demography of C. rhizophorarum in previous studies. From late summer, juveniles of the first-year cohorts appeared patchily at 12–16 cm lower tidal heights than snails of the oldest cohorts and reached 5.0–7.5 mm in mean shell length by the first mid-autumn. In the second year, juveniles gradually moved upward and appeared at higher tidal heights. The second-year cohorts reached 15.6–19.1 mm in mean shell length by the end of the second autumn and converged into the oldest cohorts during the third year or later. Our results suggest that C. rhizophorarum matures sexually and starts reproduction from the fourth summer at the earliest. On the other hand, older snails showed a similar seasonal migration pattern every year—downward movement in summer and upward movement in autumn—probably associated with their reproductive activity and/or a seasonal change in the maximum tidal height. For conservation of C. rhizophorarum, it is very important to preserve both the higher area as a main habitat for older snails and the lower tidal flat as the nursery ground.  相似文献   

14.
While the ecology and evolution of partial migratory systems (defined broadly to include skip spawning) have been well studied, we are only beginning to understand how partial migratory populations are responding to ongoing environmental change. Environmental change can lead to differences in the fitness of residents and migrants, which could eventually lead to changes in the frequency of the strategies in the overall population. Here, we address questions concerning the life history of the endangered Gila cypha (humpback chub) in the regulated Colorado River and the unregulated tributary and primary spawning area, the Little Colorado River. We develop eight multistate models for the population based on three movement hypotheses, in which states are defined in terms of fish size classes and river locations. We fit these models to mark–recapture data collected in 2009–2012. We compare survival and growth estimates between the Colorado River and Little Colorado River and calculate abundances for all size classes. The best model supports the hypotheses that larger adults spawn more frequently than smaller adults, that there are residents in the spawning grounds, and that juveniles move out of the Little Colorado River in large numbers during the monsoon season (July–September). Monthly survival rates for G. cypha in the Colorado River are higher than in the Little Colorado River in all size classes; however, growth is slower. While the hypothetical life histories of life‐long residents in the Little Colorado River and partial migrants spending most of its time in the Colorado River are very different, they lead to roughly similar fitness expectations when we used expected number of spawns as a proxy. However, more research is needed because our study period covers a period of years when conditions in the Colorado River for G. cypha are likely to have been better than has been typical over the last few decades.  相似文献   

15.
The great white shark, Carcharodoncarcharias, is the most widely protectedelasmobranch in the world, and is classified asVulnerable by the IUCN and listed on AppendixIII of CITES. Monitoring of trade in whiteshark products and enforcement of harvest andtrade prohibitions is problematic, however, inlarge part due to difficulties in identifyingmarketed shark parts (e.g., dried fins, meatand processed carcasses) to species level. Toaddress these conservation and managementproblems, we have developed a rapid, moleculardiagnostic assay based on species-specific PCRprimer design for accurate identification ofwhite shark body parts, including dried fins. The assay is novel in several respects: Itemploys a multiplex PCR assay utilizing bothnuclear (ribosomal internal transcribed spacer2) and mitochondrial (cytochrome b) locisimultaneously to achieve a highly robustmeasure of diagnostic accuracy; it is verysensitive, detecting the presence of whiteshark DNA in a mixture of genomic DNAs from upto ten different commercially fished sharkspecies pooled together in a single PCR tube;and it successfully identifies white shark DNAfrom globally distributed animals. Inaddition to its utility for white shark trademonitoring and conservation applications, thishighly streamlined, bi-organelle, multiplex PCRassay may prove useful as a general model forthe design of genetic assays aimed at detectingbody parts from other protected and threatenedspecies.  相似文献   

16.
The diversity and genetic structure of seven populations of Microcycas calocoma (Miq.) A. DC, were analyzed by gel electrophoresis using 19 allozymes. The mean number of alleles per locus (A) was 1.49 and the percentage of polymorphic loci was relatively high (P = 48.09). The mean observed (Ho) and expected heterozygosity (He) were 0.20 and 0.17, respectively. The F-statistics revealed a high population structure (Fst = 0.34). Mean gene flow between population pairs was Nm = 0.96. Results were compared with those of other cycad species, and indicate that M. calocoma populations have become fragmented due to increasing pressures of habitat conversion and disturbance. Also, geographical isolation among populations has generated allele loss in relation to altitude. The establishment and maintenance of protected areas for in situ conservation is critical to preserve the high genetic diversity of M. calocoma. Conservation strategy guidelines have been specified.  相似文献   

17.
Feral cats have been directly responsible for the extinction of numerous species on islands worldwide, including endemic species of mammals, birds and reptiles. The diet of feral cats in the main habitats of the Canary Islands, as generally occurred on oceanic islands, is mainly composed of introduced mammals, and native species of birds, reptiles and insects. The impact of feral cat upon the endangered species was assessed by evaluating their relative abundance in the cats’ diet and by considering their current conservation status. A total of 68 different preys were identified at species level in all studies carried out in the Canary Islands (5 mammals, 16 birds, 15 reptiles and 32 invertebrates). From all the species preyed by feral cats in the Canary Islands, only four of them are considered threatened by the IUCN Red List of Threatened Species: one endemic bird Saxicola dacotiae and three endemic giant lizards, Gallotia simonyi, Gallotia intermedia, and Gallotia gomerana. Although some efforts on management control have been carried out, it is necessary to enforce these conservation activities on those areas of Tenerife, La Gomera and El Hierro where giant lizards are still present. Furthermore some local areas where endangered bird species are highly predated should be protected. Nevertheless, it is important to take into account the presence of other introduced species such as rats, mice or rabbits in order to avoid problems derived from the hyperpredation process and mesopredator release effect.  相似文献   

18.
Epinephelus itajara is one of the marine fish species most threatened for extinction and it is considered to be “critically endangered” by the IUCN. The present study evaluated the genetic diversity of the species and the genetic/evolutionary relationships of its populations along the Atlantic coast of South America. The results indicate relatively reduced genetic variation, re-emphasizing the low adaptive potential of the species. One of the populations presented relatively high degrees of genetic diversity and it is evolutionary isolated from the all other populations. The evidences indicate the existence of two Evolutionarily Significant Units comprising E. itajara in the Atlantic coast of South America and the conservation prospects for the species must take these evidences into account.  相似文献   

19.
A molecular analysis was carried out on the European hermit beetles (the Osmoderma eremita species complex) to explore their genetic diversification and the robustness of previous morphologically based taxonomic arrangements. Complete sequences of mtDNA cytochrome C oxidase I gene were obtained from 26 individuals. Mean levels of interspecific sequence divergence ranged from 0.044 to 0.186. The results indicate a clear-cut distinction between two clades. The first one includes the W-European O. eremita Scopoli 1763 ; and the two Italian endemic taxa Osmoderma italicum Sparacio, 2000 and Osmoderma cristinae Sparacio, 1994 ; from southern peninsular Italy and Sicily, respectively. The second one includes the widespread E-European Osmoderma barnabita ; and the southern Balcanic Osmoderma lassallei Baraud and Tauzin, 1991 from Greece and European Turkey. Within the two clades, molecular and morphological data well support a specific rank for O. lassallei and O. barnabita on one side, and for O. eremita and O. cristinae on the other side, while the taxonomic position of O. italicum , more closely related to O. eremita , is still uncertain. Current geographical distribution, interspecific genetic diversification, and very low levels of intraspecific genetic divergence in western European populations of O. eremita sensu stricto are hypothesized to be the result of multiple speciation events (mainly occurred in refugial forest areas of the Italian and Balkan peninsulas and Sicily before and during the Pleistocene glacial peaks), followed by fast post-glacial northward and westward expansion of some species.  相似文献   

20.
Summary   Managers of wildlife populations with a wide geographical range are understandably interested in the question of whether they can manage a broader population with a single conservation strategy (e.g. covering a set of adjacent management regions, referred to as 'catchments' in Australia) or whether separate strategies are required for individual catchments. We addressed this question using data from a statewide, community wildlife survey to quantify Koala ( Phascolarctos cinereus ) habitat relationships in the catchments of four adjacent Catchment Management Authorities or CMA (>10 000 km2) of New South Wales, Australia and then tested whether these habitat relationships were similar across catchments. Although the results were constrained by the coarse resolution of the community survey and environmental data, we were able to model broad-scale patterns of habitat use. Model explanatory power and cross-regional predictability was low, but consistent with Koala ecology. Two environmental variables emerged as having a strong relationship with Koala presence – mean elevation and percentage of fertile soils – the importance of which varied among catchments depending on land-use patterns. The results highlight the need for local wildlife management plans, not a single plan covering multiple catchments.  相似文献   

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