Genetic diversity and its effect on fitness in an endangered plant species, <Emphasis Type="Italic">Dracocephalum austriacum</Emphasis> L.

The aim of this study was to estimate genetic diversity and assess its importance for plant fitness in a species belonging to the most endangered species in Europe, Dracocephalum austriacum L., and to select the most valuable populations for conservation of genetic diversity within the species in the studied regions. We analyzed allozyme variation of 12 populations in three distinct regions (Czech Karst, Moravia and Slovak Karst) in Central Europe. The results showed high genetic diversity within populations (80.14%) and relatively low differentiation among populations within regions (9.42%) and between regions (10.45%). Seed production was significantly higher in larger, genetically more diverse and less inbred populations. The results suggest that genetic diversity has important effect on seed production in this species and thus can be expected to have strong direct consequences for plant fitness and vitality of the whole populations. They also show large variation in genetic diversity between populations and indicate which populations should get a priority in attempts to conserve all the genetic diversity within the region.     

Genetic evidence of recent migration among isolated-by-sea populations of the freshwater blenny (<Emphasis Type="Italic">Salaria fluviatilis</Emphasis>)

Genetic diversity is the raw material for evolutionary change, so a species’ capacity to maintain its genetic diversity is a major concern in conservation genetics. Although genetic diversity within a population is reduced through time by genetic drift, gene flow among populations can act to recover or add new genetic variants. The goal of this study was to infer potential connectivity among isolated-by-sea populations of the vulnerable freshwater blenny (Salaria fluviatilis) and to determine if gene flow could contribute to maintaining genetic diversity in connected populations. Four genetic clusters (one small at the North, one large at the South for both East and West coasts) were detected with different clustering methods (FLOCK, STUCTURE, UPGMA, AMOVA). The two larger genetic clusters with higher migration-rate estimates among localities had higher genetic diversity and allelic richness and lower relatedness between individuals, compared to isolated localities found in smaller clusters. Our results also suggest that sea currents may facilitate fish movements among neighbouring rivers. Overall, gene flow among isolated-by-sea but close rivers could maintain the evolutionary potential of freshwater blenny populations. This finding should be considered when elaborating a conservation program for this species.     

The gap between the concept and definitions in the Evolutionarily Significant Unit: the need to integrate neutral genetic variation and adaptive variation

The Evolutionarily Significant Unit (ESU) was conceptualized in 1986 as a conservation unit below the species level, theoretically applicable to a wide range of taxa. The concept has gained support, and various definitions or criteria, some of which are inconsistent with each other, have since been proposed. Recent critiques of the ESU have pointed out the dominance of definitions biased to the identification of long-term isolation or neutral genetic variation, which has largely ignored the adaptive components. We present here the validity of such claims and show how the ESU definitions have actually been applied in research. We surveyed scientific journals for original papers supporting ESU designations and determined who among the proponents of ESU definitions have gained wider support. Our results indicate that indeed there are inconsistencies with the original concept and with the existing definitions. Although the original concept recommended both ecological and genetic data as the basis for identification of ESUs, which reflect true evolutionary variation, recent definitions have become biased to either neutral genetic variation or adaptive variation. The definition which uses genetic data to assess neutral genetic variation (long-term isolation) has gained major support, and therefore validates the earlier claims. To bridge the gap between the original concept and the practical application, we propose the use of partial ESU and full ESU designations. The application of full ESU should be limited solely to when both information about neutral genetic variation and adaptive variation are available. In other cases, in which only a part of the variation is examined, we should use the term partial ESU (e.g., molecular-based ESU) and continue to investigate focal populations from other aspects of variations to designate full ESU.     

Phylogeography of the threatened butterfly, the woodland brown Lopinga achine (Nymphalidae: Satyrinae): implications for conservation

We have studied the phylogeography of the red-listed Palearctic butterfly Lopinga achine (Nymphalidae: Satyrinae) based on 1,450 base pairs of mitochondrial DNA sequences from 86 individuals representing 12 populations. Our results indicate a strong structuring of genetic variation, with among-population differences accounting for ca. 67% of the variation and almost all populations being significantly differentiated from each other. We surmise that the insular nature of populations as well as the low dispersal ability of the species has given rise to such a pattern. The genetic diversity within populations is low compared to that in other butterflies. Our results point to a scenario where the species originated in the Eastern Palearctic and expanded into Europe. Based on the analyses, we suggest that the Czech population merits the highest conservation priority. The two Swedish populations represent a distinct evolutionary lineage, and hence merit high conservation attention. The Estonian and Asian populations had the highest genetic diversity, and although we do not consider them to be under immediate threat, their genetic diversity should be conserved in the long term.     

Update of genetic information for the white-clawed crayfish in Spain,with new insights into its population genetics and origin

The white-clawed crayfish is endemic to western and southern Europe and its populations have decreased over recent decades. Spanish populations are generally poorly represented in scientific reports and are usually studied only with a single molecular marker. Here, we use two mitochondrial markers (cytochrome oxidase subunit I and rDNA 16S genes) to examine levels and patterns of genetic structure across the range of the species’ distribution in Spain. Data reveal the existence of two main genetic groups of white-clawed crayfish in Spain with the Ebro basin as a possible contact zone. Processes occurred in historical and recent times, such as genetic drift and translocations, contribute greatly to this genetic structure. Levels of genetic variability and genetic structure of Spanish populations together with demographic inferences suggest that the species established in the Iberian Peninsula, at least since the Late Pleistocene. Knowing the true origin of the Spanish populations is crucial when deciding upon the management policies that should be followed. Given the lack of any clear evidence against its indigenous status, we propose that current protection and conservation measures should be maintained. From a management point of view, we suggest that Spanish population should be considered as a single evolutionary significant unit (ESU) with two management units (MUs) corresponding with the genetic clusters detected in the present study.     

Conservation genetics of xerothermic beetles in Europe: the case of <Emphasis Type="Italic">Centricnemus leucogrammus</Emphasis>

Xerothermic habitats are closely related to continental steppes of Eurasia and contain communities rich in rare and endemic species, especially insects. Considering the dramatic loss of xerothermic habitats due to climatic and anthropogenic changes the evaluation of genetic variation and phylogeographical patterns in xerothermic species is a matter of utmost importance if appropriate conservation measures are to be undertaken. In this paper 3 mitochondrial genes and 3 nuclear markers were used for evaluation of genetic diversity of populations of the weevil Centricnemus leucogrammus from central-east Europe. These data were used for the recognition of conservation units as well as centers of genetic diversity which could be considered as present “warm-stage” refugia for xerothermic beetle assemblages. The most diverse are eastern and central populations from Ukraine and central Poland, however, also isolated groups of populations from the Pannonian Basin and northern Poland possessed a unique genetic signature. This lead to the conclusion that all three regional groups of populations are significantly isolated from each other and represent distinct evolutionary lineages so they should be considered as separate Management Units and Evolutionary Significant Units. C. leucogrammus can be regarded as an excellent representative for typically xerothermophilous, flightless beetles and knowledge about its genetic diversity may be used for the conservation and management of entire xerothermic communities, especially for those with low mobility invertebrate taxa. Further research on the genetic diversity of various organisms with varying levels of mobility should be undertaken to broaden our knowledge on the conservations needs of xerothermic assemblages.     

基于cpDNA trnL-F序列的胡黄连保护遗传学研究

胡黄连为特产中国-喜马拉雅特有高山植物,作为常用中、藏药材,受到灭绝性采挖,作为濒危和二级保护植物亟待科学的保护。该研究以云南和西藏7个野生居群91个个体为材料,基于 cpDNA trnL-F 非编码序列测序分析胡黄连的遗传多样性和遗传结构,分析显著进化单元,确立优先保护居群并提出科学的保护策略。结果表明：胡黄连 trnL-F 序列长度为871~876 bp,根据序列的核苷酸变异共鉴定出5个单倍型,西藏占有2个单倍型,云南占有3个单倍型,西藏和云南2个地区的所有单倍型均不共享。胡黄连具有较低的单倍型多样性(Hd ＝0.43419)和核苷酸多样性(Dij ＝0.00466)。种群间分化度(Fst ＝0.864520)和基因流(Nm ＝0.04)、居群间的遗传分化水平(GST ＝0.916)、AMOVA 分析(0.78％的遗传变异发生在居群内,60.97％的遗传变异发生在地区内居群间,38.25％的遗传变异发生在地区间)均表明,胡黄连居群间存在明显遗传分化。多数一致性树将胡黄连划分为3个进化分支(Ⅰ、Ⅱ、Ⅲ),这3个分支均与地理相关,分支Ⅰ分布于横断山区的4个居群,分支Ⅱ是分布于东喜马拉雅的一个居群,分支Ⅲ是分布于喜马拉雅中段的2个居群。3个分支分属于3个“进化显著单元(ESU)”。这3个 ESU 中白马雪山、茨中、定日、波密、聂拉木五个居群都需要保护,建议现阶段应优先保护的居群是云南白马雪山和西藏波密居群,以就地保护为主。     

Population genetic structure of the endangered crayfish Austropotamobius pallipes in France based on microsatellite variation: biogeographical inferences and conservation implications

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.     

Threatened populations of the Australian squirrel glider (Petaurus norfolcensis) show evidence of evolutionary distinctiveness on a Late Pleistocene timescale

The squirrel glider Petaurus norfolcensis occurs across a broad Australian latitudinal range that includes gaps in distribution and potential biogeographic barriers, creating the potential for evolution of distinct entities within this species. Because of the species’ threatened status in the southern part of its range, we tested for the presence of geographically based independent evolutionary units among gliders sampled from southern, and northern coastal populations, using sequences of mitochondrial cytochrome b DNA (mtDNA) and a set of five nuclear microsatellites in 258 individuals. Our analyses suggest that an initial northward colonisation in the early- to mid-Pleistocene was followed by isolation by distance and, eventually, divergence between the sampled coastal and southern populations in the mid- to late-Pleistocene. We propose that the previously large and diverse southern populations have declined coincidentally with the replacement of wet forests by open sclerophyll woodlands during the preceding few million years. By contrast coastal populations further north appear to have been expanding and at present have an effective population size several times greater than southern populations. These results suggest that the two forms are on different evolutionary trajectories and should be treated separately for conservation purposes. It is highly desirable that loss of southern populations be prevented to maintain the unique genetic diversity accumulated over a considerable evolutionary timescale.     

Conservation implications of significant population differentiation in an endangered estuarine seahorse

The spatial distribution of a species’ genetic diversity can provide insights into underlying evolutionary, ecological and environmental processes, and can contribute information towards the delineation of conservation units. The Knysna seahorse, Hippocampus capensis, is endangered and occurs in only three estuaries on the warm-temperate south coast of South Africa: Knsyna, Keurbooms and Swartvlei. Population sizes in the latter two estuaries have been very small for a prolonged period of time, and the populations residing in them may thus benefit from translocations as a means of increasing population sizes and possibly also genetic diversity. However, information on whether these three estuaries constitute distinct conservation units that warrant separate management is presently lacking. Here, we used genetic information from mitochondrial (control region) and nuclear microsatellite loci to assess the genetic diversity and spatial structure across the three estuaries, and also whether translocations should be included in the management plan for the Knysna seahorse. Although each population had a unique combination of alleles, and clustering methods identified the Swartvlei Estuary as being distinct from the others, levels of genetic admixture were high, and there was no evidence for reciprocal monophyly that would indicate that each estuary has a unique demographic history. On these grounds, we suggest recognising the three populations as a single evolutionarily significant unit (ESU), and encourage translocations between them to ensure the species’ long-term survival.     

Phylogeographic evidence links the threatened ‘Grampians’ Mountain Dragon (Rankinia diemensis Grampians) with Tasmanian populations: conservation implications in south-eastern Australia

The importance of protecting genetic diversity within a species is increasingly being recognised by conservation management authorities. However, discrepancies in conservation policy between authorities, such as state versus national bodies, can have significant implications for species management when they cross state boundaries. We conducted a phylogeographic study of the south-eastern Australian lizard Rankinia diemensis to identify evolutionary significant units (ESUs), including the endangered population from the Grampians National Park in western Victoria. Phylogenetic analyses of two gene regions (mtDNA: ND2; nuclear: RAG1) revealed high levels of genetic divergence between populations, indicating isolation over long evolutionary time frames. Based on criteria of genetic divergence and isolation, R. diemensis contains at least two ESUs that require specific management. We found that R. diemensis from the Grampians are closely related to Tasmanian populations, but that the divergence between these regions is great enough (3.7 % mtDNA) that they should be considered separate ESUs. However, we believe the close evolutionary ties between these two regions needs to be taken into account; yet under current practises, conservation management of subspecific ESUs relies on state-level efforts. We argue that another population that occurs on the Victorian coast also qualifies as an ESU and requires targeted conservation action. Rankinia diemensis provides a case-in-point of the discrepancy between the state-level approach of maintaining genetic variation within a species and the more conservative Commonwealth focus on conserving biodiversity at the species level.     

From connectivity to isolation: genetic consequences of population fragmentation in capercaillie across Europe

The capercaillie inhabits a continuous range in large parts of the Palearctic boreal forest, but is patchily distributed in temperate Europe. An ongoing population decline, largely related to human land use changes, has been most pronounced in central and western Europe, where some local populations have become extinct. In this study, we document the genetic differentiation of capercaillie populations at different stages along a gradient of spatial structuring from high connectivity (continuous range in the boreal forest) to a metapopulation systems (Alps) and recent (central Europe) and historic (Pyrenees) isolation. Four hundred and sixty individuals from 14 sample sites were genotyped at 10 polymorphic microsatellite loci to assess genetic structure and variation of capercaillie populations across its European range. As expected, differentiation was least pronounced within the continuous range in the boreal forest. Within the metapopulation system of the Alps, differentiation was less than among the isolated populations of central Europe (Black Forest, Fichtelgebirge, Thuringia, Vosges). In the long-isolated population of the Pyrenees, and the recently isolated populations of central Europe, genetic diversity was significantly reduced compared with the Alps and boreal forest. Our results agree with the concept of a gradual increase in genetic differentiation from connectivity to isolation, and from recent to historic isolation. Anthropogenic habitat deterioration and fragmentation thus not only leads to range contractions and extinctions, but may also have significant genetic and evolutionary consequences for surviving populations. To maintain high levels of genetic variation in species in fragmented habitats, conservation should aim at securing connectivity between spatially distinct populations.     

Conservation genetics of Sinai’s remnant populations of Moringa peregrina, an economically valuable medicinal plant

Moringa peregrina is an economically valuable tree of Egyptian deserts. It is used medicinally, provides a highly nutritious supplement to Bedouin diets, provides fodder for livestock, and is used for fire wood. M. peregrina seeds have been a source of high-quality oil for cosmetics and perfumes since antiquity. Due to unmanaged grazing and over-collection, M. peregrina has become one of the most endangered tree species in the Egyptian desert ecosystem. A long-term conservation program is urgently needed to maintain or increase the number and size of M. peregrina populations. Ten populations harboring a total of 130 adult M. peregrina were sampled from three disjunct Wadis in South Sinai (W. Me’ar, W. Fieran and W. Zaghra). Open-pollinated seedlings were electrophoretically analyzed to address two basic questions: (1) how is genetic diversity distributed within and among populations within these three Wadis; and (2) what is the mating system of this species. M. peregrina has a mixed mating system with a selfing rate up to 16% and has limited genetic diversity within and significant genetic differentiation among its populations, the majority of which occurs among Wadis. Direct protection is urgently needed to decrease genetic deterioration within M. peregrina populations and to improve their ability to maintain or improve their population numbers. The priority of in situ conservation should be to conserve a few large well-distributed populations representing different Wadis. Ex situ germplasm collections should be made across the species’ range to ensure a representative sample of its genetic variation. Seed orchards designed to maximize cross-fertilization among unrelated individuals should be established to generate propagules to supplement natural populations.     

Genetic diversity across natural populations of <Emphasis Type="Italic">Dendrobium officinale</Emphasis>, the endangered medicinal herb endemic to China,revealed by ISSR and RAPD markers

Dendrobium officinale is a rare and endangered herb with special habitats and endemic to China. Genetic diversity was examined within and among nine natural populations using inter-simple sequence repeat (ISSR) and random amplified polymorphic (RAPD) for conservation. Both molecular markers revealed a high percentage (>89%) of polymorphic bands and ISSR markers detected more diversity than RAPD markers. Analysis of molecular variance (AMOVA) revealed that 78.84% (ISSR) and 78.88% (RAPD) of variability was partitioned among individuals within populations. This genetic structure was probably due to severe genetic drift resulting from habitat fragmentation and human overexploitation since 1950s. Moreover, there is a lack of significant association between genetic and geographic distances (r = 0.276; p > 0.05) in the populations of D. officinale. From the conservation point of view, populations GL, GS and GSD with higher genetic diversity should be protected firstly to maintain the species potential for evolutionary change and population YG with lower diversity but representing a novel evolutionary unit should also be paid more attention to during D. officinale conservation practice. Published in Russian in Genetika, 2009, Vol. 45, No. 3, pp. 375–382. The article is published in the original.     

Drainage-independent genetic structure and high genetic diversity of endangered freshwater pearl mussels (<Emphasis Type="Italic">Margaritifera margaritifera</Emphasis>) in northern Europe

Freshwater pearl mussels (Margaritifera margaritifera) are among the most critically threatened bivalve molluscs worldwide. An understanding of spatial patterns of genetic diversity is crucial for the development of integrative conservation strategies. We used microsatellites to study the genetic diversity and differentiation of 14 populations of M. margaritifera in central Sweden, an area which was described as a major secondary contact zone in postglacial colonisation for other species. Genetic diversity of Swedish pearl mussel populations was much greater than in central and southern Europe but similar to the genetic diversity observed in the northeastern portion of their European range. Genetic differentiation among populations was pronounced but to a large extent independent from present-day drainage systems. The complex patterns of genetic diversity and differentiation in pearl mussel seem to be strongly influenced by the species’ high degree of specialisation and extraordinary life history strategy which involves facultative hermaphrodism and an obligatory encystment stage on a host fish. Genetic drift effects and anthropogenic disturbances resulting in reduction of population size and loss of connectivity are less pronounced in northern pearl mussel populations compared to those in central and southern Europe.     

Reduced genetic diversity in Bearded Vultures Gypaetus barbatus in Southern Africa

The Bearded Vulture Gypaetus barbatus occurs throughout its range in small and dwindling population fragments with limited genetic differentiation between populations, suggesting that the species might be managed as a single entity. The numbers of East and Southern African Bearded Vultures included in previous studies were small, so we determine the genetic variation within, evolutionary placement of and connectivity among sub‐Saharan African populations. Mitochondrial DNA fragment analyses detected little or no differentiation between populations in Ethiopia and Southern Africa, with reduced haplotype diversity in Southern Africa compared with populations in the Northern Hemisphere. The results inform conservation management of this species globally and locally, and offer guidelines for translocations should populations continue to decline.     

Reticulate evolution and phenotypic diversity in North American ciscoes, Coregonus ssp. (Teleostei: Salmonidae): implications for the conservation of an evolutionary legacy

Coregonine fishes are notorious taxonomicproblems due to their extreme morphological andecological variation. In North America, diversity is particularly baffling among ciscoes, and both morphological and phylogenetic analyses have resulted in major polytomy among the 8 taxa of the ``Coregonus artedi' species complex. Ciscoes arealso a devastated group, accounting for 10% ofthe fish species listed by the Committee on theStatus of Endangered Wildlife in Canada. Here,we complete the genetic characterization ofNorth American ciscoes with mitochondrial andmicrosatellites markers previously used toanalyse populations of C. artedi in orderto elucidate the evolutionary history andidentify appropriate conservation units. Ourresults revealed a complex evolutionary historymarked by postglacial reticulation eventscoupled with recent and independent evolutionof similar phenotypes (taxa). Genetic variationreflects geography rather than taxonomy, andconsequently, we recommend that a single taxon,C. artedi (sensu lato) be recognized.Local genetic differentiation is often coupledwith ecophenotypic diversification, and gillraker polymorphisms, depth-related habitatpreference and reproductive behaviour areconsidered as phenotypic traits with probableadaptive value contributing to the nicheexpansion of ciscoes. Ecomorphotypes of eachparticular locale thus represent a uniqueexpression of a diverse genetic pool stillundergoing divergence and sorting.Consequently, ciscoes from lakes with distinctecomorphotypes are recognized as ESUs, as wellas each of sympatric forms when they aregenetically differentiated. We recommend thatan ESU strategy focusing at a very local levelbe adopted for continental ciscoes as a validalternative to protect significant evolutionaryprocesses of divergence encountered inpolytypic species of newly colonized habitats.     

Integrating population genetics to define conservation units from the core to the edge of Rhinolophus ferrumequinum western range

The greater horseshoe bat (Rhinolophus ferrumequinum) is among the most widespread bat species in Europe but it has experienced severe declines, especially in Northern Europe. This species is listed Near Threatened in the European IUCN Red List of Threatened Animals, and it is considered to be highly sensitive to human activities and particularly to habitat fragmentation. Therefore, understanding the population boundaries and demographic history of populations of this species is of primary importance to assess relevant conservation strategies. In this study, we used 17 microsatellite markers to assess the genetic diversity, the genetic structure, and the demographic history of R. ferrumequinum colonies in the western part of its distribution. We identified one large population showing high levels of genetic diversity and large population size. Lower estimates were found in England and northern France. Analyses of clustering and isolation by distance suggested that the Channel and the Mediterranean seas could impede R. ferrumequinum gene flow. These results provide important information to improve the delineation of R. ferrumequinum management units. We suggest that a large management unit corresponding to the population ranging from Spanish Basque Country to northern France must be considered. Particular attention should be given to mating territories as they seem to play a key role in maintaining high levels of genetic mixing between colonies. Smaller management units corresponding to English and northern France colonies must also be implemented. These insular or peripheral colonies could be at higher risk of extinction in the near future.     

青藏高原濒危植物唐古特大黄的遗传多样性

唐古特大黄(Rheum tanguticum)是中国传统的中藏药材,近几年由于生境的严重破坏,已濒临灭绝,并被列入濒危植物名单。为了探索唐古特大黄物种濒危的原因并保护其野生资源,本研究采集了9个居群87个个体的唐古特大黄样本,基于该物种的叶绿体基因trn S-G序列对其进行了遗传多样性研究。结果表明,唐古特大黄物种具有较高的遗传多样性水平(Ht=0.694),其中95.97%的遗传分化来自于居群间(G_(ST)=0.960),4.03%的遗传分化来自于居群内(Hs=0.028)。AMOVA分析也显示唐古特大黄居群间基因流较小(N_m=0.01),存在较高的遗传分化(F_(ST)=0.9631)。唐古特大黄较高的遗传多样性水平可能与该物种较长的进化史和生活史有关,居群间较高的遗传分化可能与高山地区特殊的地理环境和人类活动有关。根据研究结果,建议对唐古特大黄所有野生居群进行就地保护,同时收集种质资源开展异地繁殖工作,以保护物种的遗传多样性,维持其进化潜力。