Scanning Electron Microscopic Studies on Seed Coat Patterns of Five Endangered Himalayan Species of Meconopsis (Papaveraceae)

Scanning electron microscopic studies of seed coat patternswere carried out on 16 populations of the endangered genus Meconopsis,the Himalayan poppy. Two different types of testa can be distinguishedin the five species of Meconopsis (M. horridula, M. paniculata,M. simplicifolia, M. sinuata, M. villosa ) investigated: (a)rugose, and (b) reticulate. The results indicate the absenceof intra- and inter-population variation in all five speciesof Meconopsis. However, seed coat patterns show a marked inter-specificdifference suggesting that they are species-specific.Copyright1995, 1999 Academic Press Himalayan poppy, Meconopsis horridula, Meconopsis paniculata, Meconopsis simplicifolia, Meconopsis sinuata, Meconopsis villosa, endangered species, seed coat patterns, scanning electron microscopy     

Evidence for an outcrossing reproductive strategy in the hermaphroditic heterobranch gastropod Valvata utahensis (valvatidae), with notes on the genetic differentiation of V. utahensis and V. humeralis

The hermaphroditic aquatic heterobranch Valvata utahensis isa federally endangered snail endemic to the Snake River corridorin southern Idaho, USA. Although an appreciable understandingof molluscan taxonomic diversity has been established withinthis ecosystem, little is currently known about the ecologyand life history of many individual species (V. utahensis included).In this study, we used a combined analysis of mitochondrialand nuclear genetic variation within V. utahensis to infer thepredominant mode of reproduction (selfing vs outcrossing) withinnatural populations of this species. Results of this analysisindicated that outcrossing is likely a common reproductive strategy.We discuss our results in the context of conservation and managementefforts for this endangered species. Furthermore, in the courseof performing our investigations, we frequently collected specimensthat were tentatively identified as V. humeralis. Given thatlittle genetic work has previously been performed within thegenus Valvata, we compared genetic data from V. utahensis withdata from V. humeralis to determine whether molecular data supportedmorphological evidence that these two taxa are distinct evolutionaryentities. Results of our analyses clearly revealed strong patternsof genetic differentiation between these two taxa and confirmedthe presence of two sympatric Valvata species within the SnakeRiver system. (Received 25 January 2006; accepted 20 April 2006)     

棉铃虫外生殖嚣的超微结构及其变异

本文对棉铃虫片Helicoverpa armigera(Hubner)雌雄外生殖器的一般构造和超微结构进行了较细致的研究。并与其近缘种作了比较研究。结果表明：在一般形态方面,棉铃虫种群内个体间变异较大,种群间分化较小：在雄性阳茎端囊的弯折数、大刺数及抱器瓣的长宽比等特征上与近缘种间有一定的重叠。在超微结构方面,种群内个体间、种群间均变异不大,但与近缘种间在雄性阳茎端囊刺构造上却有明显的、间断的差异,这一差异为近缘种的鉴别 提供了新的、可靠的特征。     

PATTERNS OF REPRODUCTION IN FOUR LITTORINA SPECIES

The reproductive periodicities of four Iittorinids, Littorinaneglecta, L. nigrolineata, L. saxatilis and L. arcana were examinedin sympatric populations at Porth Swtan, Anglesey, North Wales.Three species, L. neglecta, L. nigrolineata and L. arcana, werefound to show marked reproductive periodicity. L. saxatilisshowed no periodicity and large numbers of animals were foundin breeding condition throughout the year. The oviparous speciesL. nigrolineata and L. arcana, came into reproductive conditionin the late summer or early autumn, L. nigrolineata in Augustand L. arcana in September, and their populations at Porth Swtanhad few individuals in breeding condition in the late springand early summer. L. neglecta, however, showed a periodicitywith high numbers of breeding animals throughout the springand summer and very low numbers in the autumn. For L. neglectathe basis of reproductive periodicity is shown to be the synchronizedannual life cycle of individuals of this species. It is thereforebelieved to differ from the other three species in which individualsare longer-lived and are supposed to undergo seasonal periodsof reproductive inactivity. (Received 2 March 1982;     

Reproductive success of the endangered shrub Buxus balearica Lam. (Buxaceae): pollen limitation, and inbreeding and outbreeding depression

The increasingly common phenomenon of habitat fragmentation raises the probability of pollination failure in a number of species, as both pollen quantity and quality often decrease as populations become isolated. We experimentally investigated whether pollen was limiting reproductive success of the endangered shrub Buxus balearica in five populations, two continental and three insular, during 2002 and 2003. Pollen limitation varied among populations and years, but such variation was not related to density or degree of isolation. All populations showed inbreeding depression at different phases of the reproductive cycle, although its effects differed greatly among sites. Between-population outcrossing did not have a consistent effect on several components of fitness. The highest levels of inbreeding depression – detected at the level of fruit and seed set- occurred at the smallest and least fecund populations from each region. This indicates that further fragmentation of the populations of this already endangered species could certainly threaten their survival.     

Widespread Chromosome Variation in the Endangered Grassland Forb Rutidosis leptorrhynchoides F. Muell. (Asteraceae: Gnaphalieae)

Rutidosis leptorrhynchoides is an endangered plant endemic tosoutheastern Australia. Chromosome analysis of 19 of the 24known populations of the species has identified 17 differentchromosome variants or cytotypes. The most common cytotypesare a diploid and a tetraploid based on x = 11, and triploidand hexaploid plants with this basic number were also observed.Diploids, triploids and tetraploids based on a second basicnumber ofx = 13 were also seen. Plants with 2 n = 24 were shownto be hybrids between diploids with the two different basicnumbers. Meiotic chromosome pairing analysis of the plants with2n = 24 showed a maximum of two trivalents indicating the presenceof extra copies of one pair of large and one pair of small chromosomesin the 2 n = 26 plants. In addition, a number of different aneuploidsof the 2 n = 22 and 2 n = 44 races were found and many of thesealso showed structural chromosomal variation. The distributionof the two main chromosome races is disjunct with the tetraploidsconfined to southern Victoria. To avoid dysgenic effects, futurere-establishment efforts for this species should avoid mixingseed from different chromosome races. Copyright 2001 Annalsof Botany Company Aneuploidy, conservation genetics, karyotypes, meiosis, polyploidy     

Small edge populations at risk: genetic diversity of the green lizard (<Emphasis Type="Italic">Lacerta viridis viridis</Emphasis>) in Germany and implications for conservation management

Edge and central populations can show great differences regarding their genetic variation and thereby also in their probability of extinction. This fact might be of great importance for the conservation strategies of endangered species. In this study we examine the level of microsatellite variability within three threatened edge populations of the green lizard subspecies Lacerta viridis viridis (Laur.) in Brandenburg (Germany) and compare the observed variation to other edge and central populations within the northern species range. We demonstrate that the northernmost edge populations contain less genetic variation in comparison to the central population. However, there were no observable significant differences to the other edge population included in this study. Surprisingly, we observed a high genetic differentiation in a small geographical range between the three endangered populations in Brandenburg, which can be explained by processes like fragmentation, isolation, genetic drift and small individual numbers within these populations. We also detected unique genetic variants (alleles), which only occurred in these populations, despite a low overall genetic variation. This study demonstrates the potential of fast evolving markers assessing the genetic status of endangered populations with a high resolution. It also illustrates the need for a comparative analysis of different regions within the species range, achieving a more exact interpretation of the genetic variation in endangered populations. This will aid future management decisions in the conservation of genetic diversity in threatened species.     

Variation of Nuclear DNA Content in the Biflorus Species of Lonchocarpus (Leguminosae)

This represents the first study of nuclear DNA content in alarge sample (135 spp.) from a tropical arboreal genus, in whicha large proportion of the species were examined (42 spp., 31.1%).Somatic chromosome numbers and 4C-DNA values for 51 taxa ofLonchocarpus are reported. All taxa were diploid with 2 n =22,but their DNA content ranged from 1.92 to 2.86 pg 4C nucleus,corresponding to a 48.95% variation in genome size. In the 74collections studied, no correlation was observed between DNAcontent and habitat altitude. Variation in nuclear DNA contentwas analysed at the level of genus, subgenus, section and subsection.Variation in genome size was also studied within some species,either among widely separated populations or among differentintraspecific taxa. Very little variation in genome size wasdetected between populations, subspecies, and varieties of thesame species. The taxonomic implications of variation in nuclearDNA content are discussed.Copyright 2000 Annals of Botany Company Lonchocarpus (Leguminosae), DNA content, chromosome number.     

A holistic approach to taxonomic evaluation of two closely related endangered freshwater mussel species, the oyster mussel Epioblasma capsaeformis and tan riffleshell Epioblasma florentina walkeri (Bivalvia: Unionidae)

Species in the genus Epioblasma have specialized life historyrequirements and represent the most endangered genus of freshwatermussels (Unionidae) in the world. A genetic characterizationof extant populations of the oyster mussel E. capsaeformis andtan riffleshell E. florentina walkeri sensu late was conductedto assess taxonomic validity and to resolve conservation issuesfor recovery planning. These mussel species exhibit pronouncedphenotypic variation, but were difficult to characterize phylogeneticallyusing DNA sequences. Monophyletic lineages, congruent with phenotypicvariation among species, were obtained only after extensiveanalysis of combined mitochondrial (1396 bp of 16S, cytochrome-b,and ND1) and nuclear (515 bp of ITS-1) DNA sequences. Incontrast, analysis of variation at 10 hypervariable DNA microsatelliteloci showed moderately to highly diverged populations basedon F_ST and R_ST values, which ranged from 0.12 to 0.39 and 0.15to 0.71, respectively. Quantitative variation between specieswas observed in fish-host specificity, with transformation successof glochidia of E. capsaeformis significantly greater (P<0.05)on greenside darter Etheostoma blennioides, and that of E. f.walkeri significantly greater (P<0.05) on fantail darterEtheostoma flabellare. Lengths of glochidia differed significantly(P<0.001) among species and populations, with mean sizesranging from 241 to 272 µm. The texture and colourof the mantle-pad of E. capsaeformis sensu stricto is smoothand bluish-white, whereas that of E. f. walkeri is pustuledand brown, with tan mottling. Based on extensive molecular,morphological and life history data, the population of E. capsaeformisfrom the Duck River, Tennessee, USA is proposed as a separatespecies, and the population of E. f. walkeri from Indian Creek,upper Clinch River, Virginia, USA is proposed as a distinctsubspecies. (Received 23 February 2005; accepted 16 January 2006)     

THE GONADS OF MARGARITIFERA AURICULARIA (SPENGLER, 1793) AND M. MARGARITIFERA (LINNAEUS, 1758) (BIVALVIA: UNIONOIDEA).

A detailed study of the gonads of two endangered species of thegenus Margaritifera living in the Iberian Peninsula, Margaritiferaauricularia (Spengler, 1793) and Margaritifera margaritifera(Linnaeus 1758), based on macroscopic and histological observationsis presented. In both species, gonadal tissue occurs withinthe visceral mass without a specific location. In hermaphrodite specimens,male and female acini are mixed in the visceral mass but canbe clearly distinguished by detailed macroscopic study. The gonadaltopography and cycle of Margaritifera auricularia is described forthe first time, indicating that the species is a female hermaphroditeand that gametogenesis occurs from December to March. Fiftypercent of Margaritifera margaritifera specimens studied werehermaphrodites and 50% females. (Received 6 March 2000; accepted 5 June 2000)     

Cryopreservation for Seedbanking of Australian Species

Recent studies have indicated that a large number of nativeAustralian species can be stored in liquid nitrogen using relativelystraightforward methods. Furthermore, it is estimated that seedfrom at least 40% of the rare and endangered species of WesternAustralia could be maintained through use of these cryopreservationtechniques. However, before cryopreservation of seed of Australianspecies can be implemented as a routine technique, physicaland chemical properties of seed must be studied. This studyhas shown that successful cryopreservation of seed could beinfluenced singly or by a combination of hardseededness, moisture,lipid content, fatty acid and amino acid composition. The studyalso details the role of in vitro methods for determining seedviability/recovery of species that are either damaged by liquidnitrogen or are difficult to germinate.Copyright 1994, 1999Academic Press Seed, cryopreservation, lipid, fatty acid, amino acid, Australian species     

Evaluating apparent competition in limiting the recovery of an endangered ungulate

Predation can disproportionately affect endangered prey populations when generalist predators are numerically linked to more abundant primary prey. Apparent competition, the term for this phenomenon, has been increasingly implicated in the declines of endangered prey populations. We examined the potential for apparent competition to limit the recovery of Sierra Nevada bighorn sheep (Ovis canadensis sierrae), an endangered subspecies under the US Endangered Species Act. Using a combination of location, demographic, and habitat data, we assessed whether cougar (Puma concolor) predation on endangered bighorn sheep was a consequence of their winter range overlap with abundant mule deer (Odocoileus hemionus). Consistent with the apparent competition hypothesis, bighorn sheep populations with higher spatial overlap with deer exhibited higher rates of cougar predation which had additive effects on adult survival. Bighorn sheep killed by cougars were primarily located within deer winter ranges, even though those areas constituted only a portion of the bighorn sheep winter ranges. We suspect that variation in sympatry between bighorn sheep and deer populations was largely driven by differences in habitat selection among bighorn sheep herds. Indeed, bighorn sheep herds that experienced the highest rates of predation and the greatest spatial overlap with deer also exhibited the strongest selection for low elevation habitat. Although predator-mediated apparent competition may limit some populations of bighorn sheep, it is not the primary factor limiting all populations, suggesting that the dynamics of different herds are highly idiosyncratic. Management plans for endangered species should consider the spatial distributions of key competitors and predators to reduce the potential for apparent competition to hijack conservation success.     

Production of dissolved organic carbon in phyloplankton cultures as measured by high-temperature catalytic oxidation and ultraviolet photo-oxidation methods

The production of dissolved organic carbon (DOC) in culturesof the diatoms Chaetoceros gracilis and Phaeodactylum tricornutum,the flagellate Isochrysis galbana, the dinoflagellate Alexandriumtamarense and a natural algal assemblage from the NorthwestArm, Halifax, Nova Scotia, Canada, was followed using a high-temperaturecatalytic oxidation (HTCO) and a UV photo-oxidation method.Molecular weight fractionation of the DOC was performed fortwo cultures: C.gracilis and I.galbana. While the DOC in theculture medium increased significantly during log-phase growthfor all organisms except the dinoflagellate, this increase wasproportional to the increase in cell numbers; the increase inDOC per cell was either small or zero. In all cultures, maximumrelease took place during stationary and senescent phases, usuallyafter cell numbers had started to decrease. In both C.gracilisand I.galbana, a major portion (>65%) of the organic matterreleased to the medium during log-phase growth had mol. wtsof <10 000 Da. The increase in DOC in the I.galbana culturein stationary and senescent phases was due to the release ofhigh-molecular-weight materials. The differences in extracellularrelease of DOC between species and between different growthstages in the same species suggest that both the species compositionand physiological state of phytoplankton populations must beknown before interpretations and predictions based on fielddata can be made. In order to determine whether the differencesin DOC values found by the HTCO and UV oxidation methods arecaused by the resistance to UV oxidation of some compounds producedby phytoplankton, rather than by less than optimum efficiencyof the UV unit used, standards must be based on naturally occurringcompounds, rather than the pure compounds normally used.     

3种海桑属濒危红树植物的种群结构与动态特征

以3种海桑属（Sonneratia）濒危红树植物——海南海桑（Sonneratia × hainanensis）、拟海桑（S. × gulngai）、卵叶海桑（S. ovata）为研究对象,通过编制静态生命表,绘制存活曲线、死亡率和消亡率等曲线分析其种群结构,并用生存分析与时间序列对其未来的数量动态进行预测,以阐述其种群结构特征和动态变化规律,为海桑属濒危植物种群的保护和恢复提供基础资料和科学依据。结果显示：（1）卵叶海桑种群结构为增长型;而由于缺乏幼龄个体,海南海桑和拟海桑均为衰退型。（2）三者的种群存活曲线都表现为Deevey-Ⅱ型,各种群的死亡率和消失率曲线的变化趋势一致,并随着龄级的增加呈波状上升趋势,其中海南海桑和拟海桑均在老龄阶段遇到了障碍,而卵叶海桑幼龄个体的发展遇到了瓶颈。（3）海南海桑和拟海桑种群自我更新能力较差,未来种群数量将逐渐衰退。卵叶海桑种群具有良好的恢复潜力,未来种群数量将逐步增加,但由于其种群个体数随龄级增加呈衰减趋势,若继续保持这种态势,将有可能导致龄级断层现象。（4）人类的养殖活动导致原有生境破碎化,产生了一系列不适宜种子萌发与幼苗生长的环境因子（光照、盐度、潮汐等）,这在很大程度上抑制了海桑属濒危植物种群的自然更新。建议在加大天然种群就地保护力度的基础上,优化迁地保护策略和科学实施野外回归,并积极开展人工辅助育种工作,突破育种难题,以保证其种群的正常更新。     

Restoration genetics of the vernal pool endemic Lasthenia conjugens (Asteraceae)

Restoration of habitat for endangered species often involves translocation of seeds or individuals from source populations to an area targeted for revegetation. Long-term persistence of a species is dependent on the maintenance of sufficient genetic variation within and among populations. Thus, knowledge and maintenance of genetic variability within rare or endangered species is essential for developing effective conservation and restoration strategies. Genetic monitoring of both natural and restored populations can provide an assessment of restoration protocol success in establishing populations that maintain levels of genetic diversity similar to those in natural populations. California’s vernal pools are home to many endangered plants, thus conservation and restoration are large components of their management. Lasthenia conjugens (Asteraceae) is a federally endangered self-incompatible vernal pool annual with gravity- dispersed seeds. Using the molecular technique of intersimple sequence repeats (ISSRs), this study assessed levels and patterns of genetic variability present within natural and restored populations of L. conjugens. At Travis Air Force Base near Fairfield, California, a vernal pool restoration project is underway. Genetic success of the ecologically based seeding protocol was examined through genetic monitoring of natural and restored populations over a three-year period. Genetic diversity remained constant across the three sampled generations. Diversity was also widely distributed across all populations. We conclude that the protocol used to establish restored populations was successful in capturing similar levels and patterns of genetic diversity to those seen within natural pools. This study also demonstrates how genetic markers can be used to inform conservation and restoration decisions.     

Discovery Of Genetically Distinct Sympatric Lineages in the Freshwater Mussel Cyprogenia Aberti (Bivalvia: Unionidae)

The western fanshell, Cyprogenia aberti, occurs in the CentralHighlands region of North America and is the only congener ofthe federally endangered fanshell, C. stegaria. Due to a reductionin range size and local extirpations, extant populations ofC. aberti have become increasingly isolated. Consequently, C.aberti has been the focus of numerous conservation efforts,yet no work has examined the degree of genetic variation amongthe species' disjunct populations. Phylogenetic analyses ofnucleotide sequences from two mitochondrial gene portions (CO1and ND1) revealed results important to the conservation managementof C. aberti. First, phylogenetic analyses do not support amonophyletic C. aberti. Second, C. aberti is comprised of asmany as five independent lineages, one of which includes thefederally endangered C. stegaria. Third, analysis recoveredtwo genetically distinct sympatric lineages of C. aberti inthe Ouachita River Drainage. These phylogenetic results suggestthat the five distinct evolutionary lineages of C. aberti shouldbe managed as separate conservation units. This study illustrateswhy it is critical to evaluate genetic variability in endangeredand threatened ‘species’ prior to implementing arecovery program. These data also reveal the value of assessingbiological diversity of nonimperiled taxa before populationsare extirpated and valuable genetic data necessary for reconstructionof evolutionary relationships is lost. (Received 24 October 2005; accepted 8 June 2006)     

REVISION OF THE GENUS ACAVUS FROM SRI LANKA (GASTROPODA: ACAVIDAE)

The genus Acavus from Sri Lanka includes three species, Acavushaemastoma (Linnaeus), Acavus superbus (L. Pfeiffer) and Acavusphoenix (L. Pfeiffer) with two subspecies, Acavus phoenix phoenix(L. Pfeiffer) and Acavus phoenix castaneus new subspecies.The conchological and anatomical differences between these species,as well as their intraspecific variation are described. Theirdistribution is shown on maps and all locality records are listed.The presence of extensive intraspecific polymorphism, the developmentof geographical subspecies and the presumable hybridizationbetween some species show that the Acavus species are not isolatedrelict species, but that speciation is in progress and thatthe radiation of the Acavus species is probably much youngerthan the radiation of the acavid genera. The three Acavus speciesare not acutely endangered at present. In contrast to manyother land snails, there is no risk of a rapid decline of theAcavus species due to deforestation, because these species alsooccur in synanthropic habitats. (Received 22 December 1998; accepted 2 October 1999)     

Formal Genetics of Ascidians

SYNOPSIS. Our knowledge of ascidian genetics is reviewed. Thepaper is primarily concerned with the author's past and currentwork on the colonial species Bolryllus schlosseri. Five Mendelianloci account for most of its impressive polychromatism. Breedingexperiments have substantiated the hypothesis of a single multialleliclocus for each of three enzymes (MDH, SOD, PGI) suggested byelectrophoretic patterns. The nuclei of three linkage groupshave been revealed. Self—fertilization entails a severeinbreeding depression. A specific self, nonself recognition,expressed by fusion or repulsion of contacting colonies, occursin this species also. At variance with Botryllus primigenus,fusible colonies of B. schlosseri are completely interfertile.This has allowed a more direct genetic analysis of the phenomenon,confirming the alleged control by a single multiallelic locus.In order to fuse, the confronted colonies must share at leastone allele. Young buds grafted in the tunic after removal ofall the zooids develop a new colony at the host's expense onlyif donor and host are fusible. This means that fusibility andhistocompatibility are strictly correlated. Chimerical colonies,obtained either in this way or following the resorption of oneof two fused colonies, are now being investigated for theirrecognition specificity and electrophoretic pattern. Preliminarydata indicate that both can be durably altered, suggesting thatthe allogeneic cell populations are persistent and renewing.     

Some Aspects of the Nesting Behavior and Reproductive Biology of Sea Turtles

Basic reproductive data from 21 green turtle (Chelonia mydas),8 leatherback (Dermochelys coriacea), 7 hawksbill (Eretmochelysimbricata), 7 olive ridley (Lepidochelys olivacea),6 loggerhead(Caretta caretta), 1 Kemp's ridley (Lepidochelys kempi), and1 flatback (Chelonia depressa) populations are provided. Someintraspecific and interspecific relationships between size ofnester and clutch, egg size and hatchling size are analyzed.Measurements of reproductive rates (=numbers of hatchlings perfemale per year) in 11 populations varied from 35 to 200 inan olive ridley and loggerhead colony, respectively. Nestingbehavior of each species is described in terms of type of nestingemergence and time spent on the nesting beach (=chelonery).The relatively large number of yolkless eggs laid by many leatherbacksand by some hawksbills invites further study. Some aspects ofsea turtle nesting behavior and reproduction are compared tothose of other chelonians.