scholarly journals Deforestation is the turning point for the spreading of a weedy epiphyte: an IBM approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cleber Juliano Neves Chaves ◽  
Bárbara Simões Santos Leal ◽  
Davi Rodrigo Rossatto ◽  
Uta Berger ◽  
Clarisse Palma-Silva
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Clonal Growth ◽  
Turning Point ◽  
Spatial Genetic Structure ◽  
Genetic Structure Of Populations ◽  
Spreading Dynamics ◽  
Rapid Spread ◽  
Abrupt Changes ◽  
Self Fertilization

AbstractThe rapid spread of many weeds into intensely disturbed landscapes is boosted by clonal growth and self-fertilization strategies, which conversely increases the genetic structure of populations. Here, we use empirical and modeling approaches to evaluate the spreading dynamics of Tillandsia recurvata (L.) L. populations, a common epiphytic weed with self-reproduction and clonal growth widespread in dry forests and deforested landscapes in the American continent. We introduce the TRec model, an individual-based approach to simulate the spreading of T. recurvata over time and across landscapes subjected to abrupt changes in tree density with the parameters adjusted according to the empirical genetic data based on microsatellites genotypes. Simulations with this model showed that the strong spatial genetic structure observed from empirical data in T. recurvata can be explained by a rapid increase in abundance and gene flow followed by stabilization after ca. 25 years. TRec model’s results also indicate that deforestation is a turning point for the rapid increase in both individual abundance and gene flow among T. recurvata subpopulations occurring in formerly dense forests. Active reforestation can, in turn, reverse such a scenario, although with a milder intensity. The genetic-based study suggests that anthropogenic changes in landscapes may strongly affect the population dynamics of species with ‘weedy’ traits.

scholarly journals Deforestation reduces the genetic structure of an epiphytic weed across space and time: an IBM approach

2020 ◽  
Author(s):  
Cleber Juliano Neves Chaves ◽  
Bárbara Simões Santos Leal ◽  
Davi Rodrigo Rossatto ◽  
Uta Berger ◽  
Clarisse Palma-Silva
Keyword(s):  
Genetic Structure ◽  
Clonal Growth ◽  
Spatial Genetic Structure ◽  
Dispersal Limitation ◽  
Anthropogenic Landscapes ◽  
Loss Of Resistance ◽  
Rapid Spread ◽  
Self Fertilization ◽  
Spatio Temporal ◽  
North And South America

AbstractDeforestation has allowed the massive dispersal and reproduction of some plants that are commonly referred to as weeds. The rapid spread of many weeds into newly disturbed landscapes is often boosted by clonal growth and self-fertilization strategies, which conversely increases the spatial genetic structure (SGS) of populations and reduces the genetic diversity. Here, we use empirical and modeling approaches to evaluate the spatio-temporal SGS dynamics of Tillandsia recurvata (L.) L., a common epiphytic weed with selfing reproduction and clonal growth widespread in dry forests and anthropically deforested landscapes in North and South America. We constructed an individual-based model (IBM) and adjusted the parameters according to empirical genetic data, to simulate the spreading of T. recurvata over time and across random landscapes with distinct tree densities. From empirical data, we observed a strong SGS among T. recurvata subpopulations hosted on neighbor trees and a contemporary spread from several population sources. Our model shows that the highest SGS appear in landscapes with more than 200 trees/ha and up to the 5th year of colonization of open landscapes (ca. 100 trees/ha) when SGS starts to reduce drastically. These results suggest that the deforestation commonly observed in anthropically transformed landscapes may reduce the dispersal limitation and genetic structure of T. recurvata subpopulations, creating suitable conditions for the rapid spread of T. recurvata from multiple surrounding sources. The combination of clonal growth and self-fertilization with the optimal conditions created by anthropogenic transformations may explain the spreading success of T. recurvata and other weeds into new landscapes. Our results indicate that the drastic reductions in tree densities induced by human-modifications in natural landscapes may lead to a partial loss of resistance for dispersal by wind and increased the conditions for T. recurvata to develop massive populations in anthropogenic landscapes.

scholarly journals Isolation by resistance across a complex coral reef seascape

2015 ◽  
Vol 282 (1812) ◽  
pp. 20151217 ◽  
Author(s):  
Luke Thomas ◽  
W. Jason Kennington ◽  
Michael Stat ◽  
Shaun P. Wilkinson ◽  
Johnathan T. Kool ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Divergence ◽  
Larval Dispersal ◽  
Population Genetic ◽  
Spatial Genetic Structure ◽  
Spatial Scales ◽  
Genetic Data ◽  
Genetic Structure Of Populations ◽  
Seascape Genetics

A detailed understanding of the genetic structure of populations and an accurate interpretation of processes driving contemporary patterns of gene flow are fundamental to successful spatial conservation management. The field of seascape genetics seeks to incorporate environmental variables and processes into analyses of population genetic data to improve our understanding of forces driving genetic divergence in the marine environment. Information about barriers to gene flow (such as ocean currents) is used to define a resistance surface to predict the spatial genetic structure of populations and explain deviations from the widely applied isolation-by-distance model. The majority of seascape approaches to date have been applied to linear coastal systems or at large spatial scales (more than 250 km), with very few applied to complex systems at regional spatial scales (less than 100 km). Here, we apply a seascape genetics approach to a peripheral population of the broadcast-spawning coral Acropora spicifera across the Houtman Abrolhos Islands, a high-latitude complex coral reef system off the central coast of Western Australia. We coupled population genetic data from a panel of microsatellite DNA markers with a biophysical dispersal model to test whether oceanographic processes could explain patterns of genetic divergence. We identified significant variation in allele frequencies over distances of less than 10 km, with significant differentiation occurring between adjacent sites but not between the most geographically distant ones. Recruitment probabilities between sites based on simulated larval dispersal were projected into a measure of resistance to connectivity that was significantly correlated with patterns of genetic divergence, demonstrating that patterns of spatial genetic structure are a function of restrictions to gene flow imposed by oceanographic currents. This study advances our understanding of the role of larval dispersal on the fine-scale genetic structure of coral populations across a complex island system and applies a methodological framework that can be tailored to suit a variety of marine organisms with a range of life-history characteristics.

Spatial genetic and clonal structure in Maianthemum dilatatum as defined by AFLP markers

2005 ◽  
Vol 83 (9) ◽  
pp. 1126-1132 ◽  
Author(s):  
Amy S.G. Wilson ◽  
Bart J. van der Kamp ◽  
Carol Ritland
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Clonal Growth ◽  
Spatial Genetic Structure ◽  
Restricted Gene Flow ◽  
Clonal Structure ◽  
Length Polymorphisms ◽  
Amplified Fragment Length Polymorphisms ◽  
Flow Processes ◽  
Low Levels

Amplified fragment length polymorphisms (AFLPs) were used to investigate the clonal and spatial genetic structure of Maianthemum dilatatum (A. Wood) Nels. & J.F. Macbr. (Convallariaceae), a clonal rhizomatous herb, which can form large patches of continuous cover. Within a subpopulation covering approximately 3 ha, all patches (n = 21) were mapped and sampled. Within these patches, 116 ramets were sampled and assigned to 74 putative genets. Small patches appeared to be single genets while larger patches were genetically heterogeneous and only moderately differentiated (ΦST = 0.291, p = 0.001). Less intense sampling in other populations produced similar results in that single genet populations were not found. Evidence of genet natality was present with the detection of five yearlings within a single season. Spatial autocorrelation measures detected spatial genetic structure attributable to both clonal growth and gene flow processes. It was concluded that within M. dilatatum populations, clonality is a significant factor, but the spatial structuring of genetic variation suggests that both low levels of restricted gene flow and repeated recruitment of genets occur.

Staying close: short local dispersal distances on a managed forest of two Patagonian Nothofagus species

2020 ◽  
Vol 93 (5) ◽  
pp. 652-661 ◽  
Author(s):  
Georgina Sola ◽  
Verónica El Mujtar ◽  
Leonardo Gallo ◽  
Giovanni G Vendramin ◽  
Paula Marchelli
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Spatial Genetic Structure ◽  
Pollen Dispersal ◽  
Dispersal Distance ◽  
Restricted Gene Flow ◽  
Fine Scale ◽  
Gene Dispersal ◽  
Mature Trees ◽  
The Impact

Abstract Understanding the impact of management on the dispersal potential of forest tree species is pivotal in the context of global change, given the implications of gene flow on species evolution. We aimed to determine the effect of logging on gene flow distances in two Nothofagus species from temperate Patagonian forests having high ecological relevance and wood quality. Therefore, a total of 778 individuals (mature trees and saplings) of Nothofagus alpina and N. obliqua, from a single plot managed 20 years ago (2.85 hectares), were mapped and genotyped at polymorphic nuclear microsatellite loci. Historical estimates of gene dispersal distance (based on fine-scale spatial genetic structure) and contemporary estimates of seed and pollen dispersal (based on spatially explicit mating models) were obtained. The results indicated restricted gene flow (gene distance ≤ 45 m, both pollen and seed), no selfing and significant seed and pollen immigration from trees located outside the studied plot but in the close surrounding area. The size of trees (diameter at breast height and height) was significantly associated with female and/or male fertility. The significant fine-scale spatial genetic structure was consistent with the restricted seed and pollen dispersal. Moreover, both estimates of gene dispersal (historical and contemporary) gave congruent results. This suggests that the recent history of logging within the study area has not significantly influenced on patterns of gene flow, which can be explained by the silviculture applied to the stand. The residual tree density maintained species composition, and the homogeneous spatial distribution of trees allowed the maintenance of gene dispersal. The short dispersal distance estimated for these two species has several implications both for understanding the evolution of the species and for defining management, conservation and restoration actions. Future replication of this study in other Nothofagus Patagonian forests would be helpful to validate our conclusions.

Spatial genetic structure and restricted gene flow in bed bugs (Cimex lectularius) populations in France

2015 ◽  
Vol 34 ◽  
pp. 236-243 ◽  
Author(s):  
Mohammad Akhoundi ◽  
Pierre Kengne ◽  
Arnaud Cannet ◽  
Cécile Brengues ◽  
Jean-Michel Berenger ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Spatial Genetic Structure ◽  
Cimex Lectularius ◽  
Restricted Gene Flow ◽  
Bed Bugs

scholarly journals Spatial Genetic Structure Within Two Contrasting Stands of Scots Pine (Pinus sylvestris L.)

2008 ◽  
Vol 57 (1-6) ◽  
pp. 193-202 ◽  
Author(s):  
I. J. Chybicki ◽  
A. Dzialuk ◽  
M. Trojankiewicz ◽  
M. Slawski ◽  
J. Burczyk
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
Genetic Structure ◽  
Pinus Sylvestris ◽  
Scots Pine ◽  
Spatial Genetic Structure ◽  
Nuclear Markers ◽  
Genetic Pool ◽  
Establishment History ◽  
Two Populations

AbstractWhen considering neutral nuclear markers, genetic differentiation of Scots pine (Pinus sylvestris L.) populations is known to be low. The homogeneity arises particularly as an effect of common ancestry in a recent evolutionary history as well as an extensive gene flow, especially through pollen. However, within populations several other forces may shape the spatial distribution of genetic variation, including establishment history, environmental and silvicultural selection. These local forces are known to produce non-random spatial patterns of genetic variation, however little is known on fine-scale spatial genetic structure of Scots pine. In this study, two stands of this species with different establishment histories, selected within one larger population located in northern Poland were genotyped and analysed for genetic variation and within-stand spatial genetic structure. Results revealed no differences in genetic variation, although stands are separated about 60 km, suggesting that the two populations share a common genetic pool. The spatial genetic structure in both stands was found to be slightly different and was attributed to differences in the mode of populations’ establishments. Finally, results confirmed that gene flow in Scots pine is extensive, causing genetic homogeneity within a single population.

Genetic diversity and gene flow patterns in two riverine plant species with contrasting life-history traits and distributions across a large inland floodplain

2020 ◽  
Vol 68 (5) ◽  
pp. 384
Author(s):  
William Higgisson ◽  
Dianne Gleeson ◽  
Linda Broadhurst ◽  
Fiona Dyer
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Water Resource ◽  
Isolation By Distance ◽  
Spatial Genetic Structure ◽  
Geographic Distance ◽  
Resource Development ◽  
Water Resource Development ◽  
Floodplain River

Gene flow is a key evolutionary driver of spatial genetic structure, reflecting demographic processes and dispersal mechanisms. Understanding how genetic structure is maintained across a landscape can assist in setting conservation objectives. In Australia, floodplains naturally experience highly variable flooding regimes that structure the vegetation communities. Flooding plays an important role, connecting communities on floodplains and enabling dispersal via hydrochory. Water resource development has changed the lateral-connectivity of floodplain-river systems. One possible consequence of these changes is reduced physical and subsequent genetic connections. This study aimed to identify and compare the population structure and dispersal patterns of tangled lignum (Duma florulenta) and river cooba (Acacia stenophylla) across a large inland floodplain using a landscape genetics approach. Both species are widespread throughout flood prone areas of arid and semiarid Australia. Tangled lignum occurs on floodplains while river cooba occurs along rivers. Leaves were collected from 144 tangled lignum plants across 10 sites and 84 river cooba plants across 6 sites, on the floodplain of the lower and mid Lachlan River, and the Murrumbidgee River, NSW. DNA was extracted and genotyped using DArTseq platforms (double digest RADseq). Genetic diversity was compared with floodplain-river connection frequency, and genetic distance (FST) was compared with river distance, geographic distance and floodplain-river connection frequency between sites. Genetic similarity increased with increasing floodplain-river connection frequency in tangled lignum but not in river cooba. In tangled lignum, sites that experience more frequent flooding had greater genetic diversity and were more genetically homogenous. There was also an isolation by distance effect where increasing geographic distance correlated with increasing genetic differentiation in tangled lignum, but not in river cooba. The distribution of river cooba along rivers facilitates regular dispersal of seeds via hydrochory regardless of river level, while the dispersal of seeds of tangled lignum between patches is dependent on flooding events. The genetic impact of water resource development may be greater for species which occur on floodplains compared with species along river channels.

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