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Long Distance Dispersal (long + distance_dispersal)
Selected AbstractsInsights into the termite assemblage of a neotropical rainforest from the spatio-temporal distribution of flying alatesINSECT CONSERVATION AND DIVERSITY, Issue 3 2009THOMAS BOURGUIGNON Abstract., 1. During the last decade, many studies have focused on the diversity of termite species and their ecological function, but these have been mostly based on transect protocols not designed to sample canopy-dwelling and subterranean species. Additionally, all these studies relied upon collections of foraging parties composed of workers and soldiers in the soil or in pieces of wood. 2. We hypothesised that alate-based protocols could disclose spatial and temporal patterns of termite flights and provide a more balanced picture of assemblages for ecological and biodiversity surveys. 3. Our study took place in the framework of the IBISCA-Panama project, which used numerous trapping methods to give a multifaceted overview of a complex tropical rainforest arthropod community. Two methods, flight interception traps and light traps, were efficient at collecting termite alates. All collected specimens were assigned to morphospecies which were later identified to the genus or species level, when possible. 4. Our results highlighted that: (i) alate trapping represents a powerful complement to ground-based standardised sampling protocols by allowing the documentation of the whole termite assemblage. (ii) Canopy dwellers fly preferentially in the upper strata, whereas no vertical stratification was found for ground dwellers, suggesting that height of flight is dictated by a pressure for long distance dispersal as well as the need to find a suitable site for colony-founding. (iii) Alates from closely related species do not stagger their flight period to avoid hybridisation but rather synchronise their flights according to environmental factors. [source] Contrasting effects of long distance seed dispersal on genetic diversity during range expansionJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2006R. BIALOZYT Abstract Currently many attempts are made to reconstruct the colonization history of plant species after the last ice age. A surprising finding is that during the colonization phase genetic diversity did not decrease as much as expected. In this paper we examine whether long distance seed dispersal events could play a role in the unexpected maintenance of genetic diversity during range expansion. This study is based on simulations carried out with a maternally inherited haploid locus using a cellular automaton. The simulations reveal a close relationship between the frequency of long distance seed dispersal events and the amount of genetic diversity preserved during colonization. In particular, when the colonized region is narrow, a complete loss of genetic diversity results from the occurrence of very rare long distance dispersal (LDD) events. We call this phenomenon the ,embolism effect'. However, slightly higher rates of LDD events reverse this effect, up to the point that diversity is better preserved than in a pure diffusion model. This phenomenon is linked to the reorganization of the genetic structure during colonization and is called the ,reshuffling effect'. [source] Spatial structure of lemming populations (Dicrostonyx groenlandicus) fluctuating in densityMOLECULAR ECOLOGY, Issue 2 2001D. Ehrich Abstract The pattern and scale of the genetic structure of populations provides valuable information for the understanding of the spatial ecology of populations, including the spatial aspects of density fluctuations. In the present paper, the genetic structure of periodically fluctuating lemmings (Dicrostonyx groenlandicus) in the Canadian Arctic was analysed using mitochondrial DNA (mtDNA) control region sequences and four nuclear microsatellite loci. Low genetic variability was found in mtDNA, while microsatellite loci were highly variable in all localities, including localities on isolated small islands. For both genetic markers the genetic differentiation was clear among geographical regions but weaker among localities within regions. Such a pattern implies gene flow within regions. Based on theoretical calculations and population census data from a snap-trapping survey, we argue that the observed genetic variability on small islands and the low level of differentiation among these islands cannot be explained without invoking long distance dispersal of lemmings over the sea ice. Such dispersal is unlikely to occur only during population density peaks. [source] Long-distance dispersal and local retention of larvae as mechanisms of recruitment in an island population of a coral reef fishAUSTRAL ECOLOGY, Issue 2 2007HEATHER M. PATTERSON Abstract Although recruitment of pelagic larvae is a fundamental and well-documented process in the dynamics of benthic marine populations, identifying the sources of recruitment, or the degree to which populations are connected via dispersal of larvae, has remained elusive for most marine taxa. In this study we used natural environmental markers (trace elements) recorded in fish otoliths (ear stones) as tags of natal origin. Specifically, we used the otolith core and edge chemistries of a locally endemic wrasse (Coris bulbifrons) from Lord Howe Island (LHI), Australia, and a widely distributed species (Coris picta) from three potential mainland source regions, to determine the likely sources of recruitment to C. picta populations on LHI. The use of a local endemic species, which is by definition self-recruiting, is a novel approach for ground-truthing the dispersal history of non-endemic coral reef fish. Discriminant function analyses were able to separate LHI from mainland fish, using both edge and core signatures, with a high degree of accuracy, suggesting at least some of the C. picta collected on LHI were of local origin. This result was corroborated when half of the C. bulbifrons and LHI C. picta were introduced as unknowns into a discriminant function analysis using the remaining C. bulbifrons, LHI C. picta, and the mainland C. picta as a training data set. Overall, our findings suggest that both long distance dispersal and local retention are important sources of recruitment to populations of C. picta on LHI and that otolith chemistry of endemic species could be a useful benchmark for determining the prevalence of self-recruitment in insular populations of other widespread species. [source] Yeasts isolated from New Zealand vineyards and wineriesAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 3 2010H.Y. ZHANG Abstract Background and Aims:, The yeast flora from a range of New Zealand commercial wineries was surveyed to estimate the incidence of yeast species in grape juice. Methods and Results:, Molecular analysis of the internal transcribed spacer region was performed for 1279 yeast colonies isolated from 17 different fresh grape juices sampled in eight New Zealand wineries between 2003 and 2009. The 17 juices contained at least 25 different species of yeast from nine genera. Microsatellite fingerprinting of Saccharomyces cerevisiae showed that some strains were identical to known commercial yeast varieties, but we also found evidence for local populations of S. cerevisiae common to individual wineries or regions. Five genotypes from Central Otago, New Zealand, were very closely related to a single sequenced strain derived from Chile, which in turn is related to European wine isolates. Conclusions:, The yeast flora found in New Zealand grape juices is broadly similar to that found in wineries elsewhere around the world. Genotyping of S. cerevisiae suggests recent dispersal of both commercial and non-commercial yeast strains from Europe to New Zealand. Significance of the Study:, These data are consistent with two human-mediated modes for the international dispersal of S. cerevisiae: one via the escape of strains traded commercially, and another via long distance dispersal of non-commercial strains. [source] Biogeographic anomaly or human introduction: a cryptogenic population of tree skink (Reptilia: Squamata) from the Cook Islands, OceaniaBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2010ALISON 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] | ||||||||||