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Introduced Populations (introduced + population)

Distribution by Scientific Domains

Life Sciences	90%

Distribution within Life Sciences

Evolution	50%
Plant Science	16%

Selected Abstracts

Morphological and Molecular Data Reveal the Presence of the Invasive Artemia franciscana in Margherita di Savoia Salterns (Italy)

INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 6 2006
Graziella Mura
Abstract Introduced populations of the American invasive Artemiafranciscana have been reported in Mediterranean countries except for Italy. A recent sampling at Margherita di Savoia revealed the presence of mating pairs in a saltwork known to host only parthenogens. An integrated approach, based on scanning electron microscopy of four morphological traits, discriminant analysis of 13 morphometric characters and 16S rRNA PCR-RFLP profiles of eight endonucleases was implemented for the identification of the invader. Patterns of variability in all assayed markers provided congruent and solid evidence that the allochthonous species is A. franciscana. Native parthenogens are still predominant (,98.4%) in this Italian site but they can be rapidly outcompeted by A. franciscana, as it occurred in similar cases throughout Europe and elsewhere. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Dynamics of an introduced population of mouflon Ovis aries on the sub-Antarctic archipelago of Kerguelen

ECOGRAPHY, Issue 3 2010
Renaud Kaeuffer
A commonly reported pattern in large herbivores is their propensity to irrupt and crash when colonizing new areas. However, the relative role of density-dependence, climate, and cohort effects on demographic rates in accounting for the irruptive dynamics of large herbivores remains unclear. Using a 37-yr time series of abundance in a mouflon Ovis aries population located on Haute Island, a sub-Antarctic island of Kerguelen, 1) we investigated if irruptive dynamics occurred and 2) we quantified the relative effects of density and climate on mouflon population dynamics. Being released in a new environment, we expected mouflon to show rapid growth and marked over-compensation. In support of this prediction, we found a two-phase dynamics, the first phase being characterised by an irruptive pattern best described by the , -Caughley model. Parameter estimates were rm=0.29±0.005(maximum growth rate), K=473±45 (carrying capacity) and S=2903±396 (surplus) mouflon. With a ,=3.18±0.69 our model also supported the hypothesis that density dependence is strongest at high density in large herbivores. The second phase was characterised by an unstable dynamics where growth rate was negatively affected by population abundance and winter precipitation. Climate, however, did not trigger population crashes and our model suggested that lagged density-dependence and over-grazing were the probable causes of mouflon irruptive dynamics. We compare our results with those of Soay sheep and discuss the possibility of a reversible alteration of the island carrying capacity after the initial over-grazing period. [source]

Is the large size of the pinna of the ear of the European hare (Lepus europaeus) due to its role in thermoregulation or in anterior capital shock absorption?

JOURNAL OF MORPHOLOGY, Issue 6 2010
Philip Stott
Abstract Large pinnae are characteristic of the Leporids, and the pinna is known to have a thermoregulatory role. Another role has been hypothesized for the pinna of Lepus spp., as a part of a suspensory system for the greater portion of the head, absorbing shock that might otherwise interfere with vision during high-speed locomotion. We compared the lengths of the pinnae of adult European hares Lepus europaeus from the source population in the cooler climate of England with those of the introduced population in the warmer climate of Australia, and we compared the lengths of the pinnae of hares that had grown in cooler weather with those that had grown in warmer weather. There were no significant differences between each of the comparisons, indicating that the size of the pinna is not determined by thermoregulatory requirements at rest. We compared the growth in length of the pinnae and the legs with growth in body mass, and growth in the mass of the pinnae with the masses of the head and the eyeballs, and found support for the suspension hypothesis. We suggest that the rapid growth of the pinna is because visual acuity is a function of absolute eye size, not relative eye size, yet juvenile hares are subject to the same predator pressure as adult hares, and equally need to maximize visual acuity while running at high speeds in dim light. We believe that the large size of the pinna is determined by its role in anterior capital suspension, not in thermoregulation. J. Morphol., 2010. © 2010 Wiley-Liss, Inc. [source]

Differential admixture shapes morphological variation among invasive populations of the lizard Anolis sagrei

MOLECULAR ECOLOGY, Issue 8 2007
JASON J. KOLBE
Abstract The biological invasion of the lizard Anolis sagrei provides an opportunity to study evolutionary mechanisms that produce morphological differentiation among non-native populations. Because the A. sagrei invasion represents multiple native-range source populations, differential admixture as well as random genetic drift and natural selection, could shape morphological evolution during the invasion. Mitochondrial DNA (mtDNA) analyses reveal seven distinct native-range source populations for 10 introduced A. sagrei populations from Florida, Louisiana and Texas (USA), and Grand Cayman, with 2,5 native-range sources contributing to each non-native population. These introduced populations differ significantly in frequencies of haplotypes from different native-range sources and in body size, toepad-lamella number, and body shape. Variation among introduced populations for both lamella number and body shape is explained by differential admixture of various source populations; mean morphological values of introduced populations are correlated with the relative genetic contributions from different native-range source populations. The number of source populations contributing to an introduced population correlates with body size, which appears independent of the relative contributions of particular source populations. Thus, differential admixture of various native-range source populations explains morphological differences among introduced A. sagrei populations. Morphological differentiation among populations is compatible with the hypothesis of selective neutrality, although we are unable to test the hypothesis of interdemic selection among introductions from different native-range source populations. [source]

Genetic variability revealed with microsatellite markers in an introduced population of the abalone Haliotis discus hannai Ino

AQUACULTURE RESEARCH, Issue 3 2009
S Marchant
Abstract One of the challenges for the culture of any species is to control the loss of genetic variability, which may result in a decrease in the quality of commercially important traits. The goal of this study is to assess the genetic diversity of a hatchery population of the Pacific abalone (Haliotis discus hannai) from the Center for Abalone Production of the Universidad Católica del Norte (CAP-UCN) that is maintained under a breeding programme. We used six polymorphic microsatellite markers within the cultivated population. The loci Awb033 and Awb079 had the highest number of alleles (11 and 10 respectively) and the loci Awb022 and Awb026 the lowest (two and four respectively). The mean number of alleles per locus was 6.83. The average observed and expected heterozygosities were 0.71 and 0.70, respectively, and the average FIS (f) index was ,0.023. We compared the population genetic parameters of the CAP-UCN population with previously published data of wild and hatchery populations of the same species. Results indicate lower genetic diversity estimated as allelic richness in the introduced population with a loss of 11,58% alleles per locus. Despite the high allelic loss, the estimated inbreeding coefficient suggests that the breeding programme carried out in the CAP-UCN has controlled and maintained heterozygosity levels successfully. A temporal study is necessary to determine whether the genetic diversity loss detected was caused during the initial introduction of breeders or to the breeding programme actually implemented. [source]

From introduction to the establishment of alien species: bioclimatic differences between presence and reproduction localities in the slider turtle

DIVERSITY AND DISTRIBUTIONS, Issue 1 2009
Gentile Francesco Ficetola
ABSTRACT Aim, Understanding the factors determining the transition from introduction of aliens to the establishment of invasive populations is a critical issue of the study of biological invasions, and has key implications for management. Differences in fitness among areas of introduction can define the zones where aliens become invasive. The American slider turtle Trachemys scripta has been introduced worldwide, and has negative effects on freshwater communities, but only a subset of introduced populations breed successfully. We used species distribution models to assess the factors influencing the slider distribution in Italy, by analysing bioclimatic features that can cause the transition from presence of feral adults to breeding populations. We also evaluated whether climate change might increase the future suitability for reproduction. Location,, Central and Northern Italy. Methods,, The distribution of slider turtle was obtained from the literature, unpublished reports and field surveys. We used Maxent to build bioclimatic models. Results,, Reproductive populations are associated to a clear bioclimatic envelope with warmer climate, more solar radiation and higher precipitations than populations where reproduction is not observed. Several Mediterranean areas currently have climatic features suitable for sliders. Scenarios of climate change predict the expansion of these areas. In the near future (2020), the proportion of populations in areas suitable for reproduction will dramatically increase. Main conclusion,, Our study shows that bioclimatic differences can determine the areas where aliens become invaders. Management should be focused to these source areas. However, climate change can increase fitness in the future, and therefore the interactions between climate change and fitness can boost the invasiveness of this alien species. [source]

Selection of preadapted populations allowed Senecio inaequidens to invade Central Europe

DIVERSITY AND DISTRIBUTIONS, Issue 4 2008
Oliver Bossdorf
ABSTRACT Invasive species often evolve rapidly in response to the novel biotic and abiotic conditions in their introduced range. Such adaptive evolutionary changes might play an important role in the success of some invasive species. Here, we investigated whether introduced European populations of the South African ragwort Senecio inaequidens (Asteraceae) have genetically diverged from native populations. We carried out a greenhouse experiment where 12 South African and 11 European populations were for several months grown at two levels of nutrient availability, as well as in the presence or absence of a generalist insect herbivore. We found that, in contrast to a current hypothesis, plants from introduced populations had a significantly lower reproductive output, but higher allocation to root biomass, and they were more tolerant to insect herbivory. Moreover, introduced populations were less genetically variable, but displayed greater plasticity in response to fertilization. Finally, introduced populations were phenotypically most similar to a subset of native populations from mountainous regions in southern Africa. Taking into account the species' likely history of introduction, our data support the idea that the invasion success of Senecio inaequidens in Central Europe is based on selective introduction of specific preadapted and plastic genotypes rather than on adaptive evolution in the introduced range. [source]

Time to establishment success for introduced signal crayfish in Sweden , a statistical evaluation when success is partially known

JOURNAL OF APPLIED ECOLOGY, Issue 5 2010
Ullrika Sahlin
Summary 1.,The signal crayfish Pacifastacus leniusculus is an invasive species in Sweden, threatening the red-listed nobel crayfish Astacus astacus through spreading the crayfish plague. Time-to-event models can handle censored data on such introduced populations for which the state (successful or not) is only partially known at the last observation, but even though data on introduced populations most often are censored, this type of model is usually not used for likelihood-based inference and predictions of the dynamics of establishing populations. 2.,We specified and fitted a probabilistic time-to-event model to be used to predict the time to successful establishment of signal crayfish populations introduced into Sweden. Important covariates of establishment success were found by the methods of ,model averaging' and ,hierarchical partitioning', considering model uncertainty and multi-colinearity, respectively. 3.,The hazard function that received the highest evidence based on the empirical data showed that the chances of establishment were highest in the time periods immediately following the first introduction. The model predicts establishment success to be <50% within 5 years after first introduction over the current distributional range of signal crayfish in Sweden today. 4.,Among covariates related to temperature, fish species and physical properties of the habitat, the length of the growing season was the most important and consistent covariate of establishment success. We found that establishment success of signal crayfish is expected to increase with the number of days when growth is possible, and decrease with the number of days with extremely high temperatures, which can be seen to approximate conditions of stress. 5.,Synthesis and applications. The results demonstrate lower establishment success of signal crayfish further north in Sweden, which may decrease the incentives of additional illegal introductions that may threaten the red-listed noble crayfish Astacus astacus. We provide a fully probabilistic statistical evaluation that quantifies uncertainty in the duration of the establishment stage that is useful for management decisions of invasive species. The combination of model averaging and hierarchical partitioning provides a comprehensive method to address multi-colinearity common to retrospective data on establishment success of invasive species. [source]

Genetics, behaviour and chemical recognition of the invading ant Pheidole megacephala

MOLECULAR ECOLOGY, Issue 2 2009
DENIS FOURNIER
Abstract Introduced species often become ecologically dominant, displacing native species and posing a serious threat to ecosystem function and global biodiversity. Ants are among the most widespread and damaging alien species; introductions are often accompanied by population-level behavioural and genetic changes contributing to their success. We investigated the genetic structure, chemical profile and nestmate recognition in introduced populations of the invasive big-headed ant, Pheidole megacephala, in Australia. Behavioural analyses show that workers are not aggressive towards conspecifics from different nests, even at large geographical scales (up to 3000 km) and between populations encompassing a wide range of environmental conditions. By contrast, interactions with workers of other species invariably result in agonistic behaviours. Genetic analyses reveal that populations have low genetic diversity. No genetic differentiation occurs among nests of the same population; differentiation between populations, though significant, remains weak. Chemical analyses indicate that cuticular lipids are similar between colonies of a population, and that differentiation between populations is low. Altogether, these results indicate that the big-headed ant P. megacephala forms a large unicolonial population across northern/eastern Australia. [source]

Differential admixture shapes morphological variation among invasive populations of the lizard Anolis sagrei

High intercontinental migration rates and population admixture in the sapstain fungus Ophiostoma ips

MOLECULAR ECOLOGY, Issue 1 2007
XUDONG ZHOU
Abstract Ophiostoma ips is a common fungal associate of various conifer-infesting bark beetles in their native ranges and has been introduced into non-native pine plantations in the Southern Hemisphere. In this study, we used 10 microsatellite markers to investigate the population biology of O. ips in native (Cuba, France, Morocco and USA) and non-native (Australia, Chile and South Africa) areas to characterize host specificity, reproductive behaviour, and the potential origin as well as patterns of spread of the fungus and its insect vectors. The markers resolved a total of 41 alleles and 75 haplotypes. Higher genetic diversity was found in the native populations than in the introduced populations. Based on the origin of the insect vectors, the populations of O. ips in Australia would be expected to reflect a North American origin, and those in Chile and South Africa to reflect a European origin. However, most alleles observed in the native European population were also found in the native North American population; only the allele frequencies among the populations varied. This admixture made it impossible to confirm the origin of the introduced Southern Hemisphere (SH) populations of O. ips. There was also no evidence for specificity of the fungus to particular bark beetle vectors or hosts. Although O. ips is thought to be mainly self-fertilizing, evidence for recombination was found in the four native populations surveyed. The higher genetic diversity in the North American than in the European population suggests that North America could be the possible source region of O. ips. [source]

Molecular evidence for a founder effect in invasive house finch (Carpodacus mexicanus) populations experiencing an emergent disease epidemic

MOLECULAR ECOLOGY, Issue 1 2006
DANA M. HAWLEY
Abstract The impact of founder events on levels of genetic variation in natural populations remains a topic of significant interest. Well-documented introductions provide a valuable opportunity to examine how founder events influence genetic diversity in invasive species. House finches (Carpodacus mexicanus) are passerine birds native to western North America, with the large eastern North American population derived from a small number of captive individuals released in the 1940s. Previous comparisons using amplified fragment length polymorphism (AFLP) markers found equivalent levels of diversity in eastern and western populations, suggesting that any genetic effects of the founder event were ameliorated by the rapid growth of the newly established population. We used an alternative marker system, 10 highly polymorphic microsatellites, to compare levels of genetic diversity between four native and five introduced house finch populations. In contrast to the AFLP comparisons, we found significantly lower allelic richness and heterozygosity in introduced populations across all loci. Three out of five introduced populations showed significant reductions in the ratio of the number of alleles to the allele size range, a within-population characteristic of recent bottlenecks. Finally, native and introduced populations showed significant pairwise differences in allele frequencies in every case, with stronger isolation by distance within the introduced than native range. Overall, our results provide compelling molecular evidence for a founder effect during the introduction of eastern house finches that reduced diversity levels at polymorphic microsatellite loci and may have contributed to the emergence of the Mycoplasma epidemic which recently swept the eastern range of this species. [source]

Microsatellite variation within and among North American lineages of Phragmites australis

MOLECULAR ECOLOGY, Issue 7 2003
K. Saltonstall
Abstract Over the past century, the spread of the common reed (Phragmites australis) has had a dramatic impact on wetland communities across North America. Although native populations of Phragmites persist, introduced invasive populations have dominated many sites and it is not clear if the two types can interbreed. This study compares patterns of differentiation in 10 microsatellite loci among North American and European Phragmites individuals with results obtained from sequencing of noncoding chloroplast DNA. Three population lineages (native, introduced and Gulf Coast) were previously identified in North America from chloroplast DNA and similar structuring was found in the nuclear genome. Each lineage was distinguished by unique alleles and allele combinations and the introduced lineage was closely related to its hypothesized source population in Europe. Size homoplasy and diagnostic base substitutions distinguishing lineages were evident at several loci, further emphasizing that native, introduced and Gulf Coast North American Phragmites lineages are genetically distinct. Gene flow between lineages was low and invasive introduced populations do not represent a hybrid population type. [source]

Highly variable microsatellite loci for studies of introduced populations of the small Indian mongoose (Herpestes javanicus)

MOLECULAR ECOLOGY RESOURCES, Issue 4 2002
C.-G. Thulin
Abstract During their introduction, non-native species typically undergo founder events that reduce genetic variation. To allow a high-resolution genetic investigation of introduced populations of the small Indian mongoose (Herpestes javanicus), we developed primers for nine variable microsatellite loci. Their applicability was assessed in 10 mongooses from the large Fijian population, which originated from a single pair from Calcutta, India. The number of alleles ranged from two to five per locus, possibly as a result of preservation of initial variability and in situ mutations during the rapid population expansion after introduction. [source]

Genetic variation in populations of the cacao wilt pathogen, Ceratocystis cacaofunesta

PLANT PATHOLOGY, Issue 6 2007
C. J. B. Engelbrecht
Ceratocystis cacaofunesta (= Ceratocystis fimbriata) causes a lethal wilt disease of cacao (Theobroma cacao) in Latin America. Polymorphic microsatellite markers, (CAT)5 nuclear DNA fingerprints and Hae III mitochondrial DNA fingerprints were used to compare genetic diversity among isolates of C. cacaofunesta collected from populations in western Ecuador, Costa Rica, Colombia, and Rondônia and Bahia in Brazil. Microsatellite markers and nuclear DNA fingerprints separated Ecuadorian isolates from isolates of the other four populations, and these two major groups correspond to genetic lineages already identified from ITS-rDNA sequences and intersterility groupings. Mitochondrial DNA fingerprints also demonstrated substantial diversity and split the Ecuadorian isolates into two groups. All marker types showed limited variation in the Colombian, Costa Rican and Bahian populations, as might be expected for introduced populations that have gone through recent genetic bottlenecks. In contrast, the Rondonian and western Ecuadorian populations showed gene diversity values similar to natural populations of other Ceratocystis species. The Rondonian population was the only sampled population in the native range of T. cacao (the Upper Amazon), and the putatively introduced populations were more closely related to the Rondonian population than to the western Ecuadorian population. The Ecuadorian population is in an area with other native Theobroma species, which may serve as natural hosts. [source]

Biogeographic anomaly or human introduction: a cryptogenic population of tree skink (Reptilia: Squamata) from the Cook Islands, Oceania

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2010
ALISON M. HAMILTON
Archaeological and molecular data have revealed that the present day faunas of many island groups in Melanesia, Polynesia, and Micronesia are not representative of the biodiversity generated within this region on an evolutionary timescale. Erroneous inferences regarding the mechanisms of speciation and the significance of long distance dispersal in shaping the present diversity of these island systems have resulted from this incomplete diversity and distributional data. The lizard fauna east of Samoa has been suggested to derive entirely from human-mediated introductions, a distribution congruent with biogeographic patterns for other Pacific species. Distinguishing between introduced populations and those that result from natural colonization events is difficult, although molecular data provide a useful means for elucidating population history and identifying the likely sources of introductions. We use molecular data (1726 bp of mitochondrial DNA and 286 bp of nuclear DNA) to evaluate a population of arboreal lizards from the Cook Islands and to determine whether this arboreal skink population is the sole endemic component of the lizard fauna east of Samoa or the result of human-mediated introduction. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 318,328. [source]

Evidence for massive clonal growth in the invasive weed Fallopia japonic a (Japanese Knotweed)

BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2000
MICHELLE L. HOLLINGSWORTH
Clonal growth in introduced populations of Japanese Knotweed (Fallopia juponica) in Britain was assessed using RAPDs (Randomly Amplified Polymorphic DNA). A total of 150 British samples was analysed for genetic variation using ten arbitrary decamer primers, and compared with data from 16 samples of other introduced populations from Europe and the U.S.A. All samples produced an identical multi-primer RAPD profile. Accepting that RAPD profile identity need not equate to genet identity, based on the sensitivity of these markers for detecting genetic diversity in related taxa and on the absence of male fertile individuals of this species in Britain, we interpret this result as consistent with the presence of a single, exceptionally widespread clone. This clone must represent one of the world's largest vascular plants. [source]