Evidence for spatial structure and directional gene flow in a population of an aquatic plant, Potamogeton coloratus

Gornall, R. J.; Hollingsworth, Peter; Preston, C.

doi:10.1038/sj.hdy.6882700

Cited by 29 publications

(35 citation statements)

References 7 publications

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“…Hence, hydrochorous dispersal is critical to the maintenance of genetic diversity in macrophyte populations. A number of studies have found that the unidirectional flow of water results in asymmetrical gene flow (Gornall, Hollingsworth, & Preston, ; Pollux et al, ). For instance, Pollux et al () found a significant increase in the genetic diversity of Sparganium emersum populations with distance downstream, gene flow being approximately 3.5 times higher in a downstream direction than upstream.…”

Section: Macrophyte Dispersal and Settlementmentioning

confidence: 99%

Impacts of artificial barriers on the connectivity and dispersal of vascular macrophytes in rivers: A critical review

et al. 2020

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1. Macrophytes play important functional roles in river ecosystems, providing habitat and food, as well as influencing flow, water chemistry, and sediment dynamics.They also represent an important component of river biodiversity.2. Artificial river barriers have the potential to disrupt macrophyte dispersal, and compromise their distribution and persistence, but little information is available compared to barrier impacts on fish and macroinvertebrates. Here, we review the mechanisms supporting dispersal of river macrophytes in rivers and evaluate the nature of barrier impacts on macrophytes.3. Hydrochory (dispersal of propagules by water) is the principal mechanism of downstream dispersal, while zoochory (dispersal of propagules by animals) is likely to be the most important vector of upstream dispersal and inter-catchment transport.4. Most studies have focused on the impact of large structures such as dams, and the findings indicate the impact is highly context dependent. Slow-flowing habitats upstream of dams can act as traps to drifting propagules and thereby interrupt hydrochory. However, the consequences of interrupted hydrochory for downstream populations are unclear. River regulation can result in lower macrophyte diversity, although the lentic habitats associated with reservoirs can also favour an increase in the abundance and richness of macrophyte communities. 5. Instream barriers are unlikely to affect zoochory by birds directly, but barriers are well known to restrict fish movements, so there is considerable potential for barriers to disrupt zoochory by fish, although no empirical study has specifically examined this possibility.6. There is a paucity of studies examining the impacts of low-head barriers on macrophyte dispersal. Given the influence of macrophytes on river processes, we call for further research into barrier impacts on macrophyte population dynamics in order to gain a better understanding of the consequences of river fragmentation for fluvial communities and ecosystem functioning. K E Y W O R D Saquatic plant, dams, hydrochory, river regulation, zoochory

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Section: Macrophyte Dispersal and Settlementmentioning

confidence: 99%

Impacts of artificial barriers on the connectivity and dispersal of vascular macrophytes in rivers: A critical review

et al. 2020

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“…Previous population genetic studies on riparian plants reported the possibilities of water‐affected dispersal that would result in characteristic patterns of genetic structure within a river system. For example, biased distributions of genetic variation between upstream and downstream populations (i.e., downstream populations harbor higher levels of genetic variation) would be the result of unidirectional seed migration from upstream sources to downstream sink populations (Waser et al, 1982; Akimoto et al, 1998; Gornall et al, 1998). A lack of a relationship between genetic and geographical distances (isolation by distance; IBD) among populations within a river may be another genetic signature of dispersal influenced by water.…”

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confidence: 99%

Multiple spatial scale patterns of genetic diversity in riparian populations ofAinsliaea faurieana(Asteraceae) on Yakushima Island, Japan

Mitsui

Isagi

Setoguchi

2010

American J of Botany

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Habitat and geographical features of river systems strongly influence gene flow and spatial genetic patterning in riparian plant populations. We investigated the patterns of genetic diversity within and among populations of Ainsliaea faurieana relative to different spatial conditions (along a river, among rivers, and among regions on an island), based on nuclear and chloroplast microsatellite DNA variations. Within an individual river system, we found higher haplotype diversities in downstream populations, and in a Bayesian analysis of recent migration, we detected unidirectional gene movements from upstream to downstream, indicating water-mediated dispersal along the river. Mantel tests detected no isolation-by-distance in genetic variation, suggesting the maintenance of a metapopulation with wide-range seed dispersal by water. Moreover, the observed high level of genetic differentiation, especially in the cpDNA (F(ST) = 0.539), indicated a metapopulation structure with frequent extinction and colonization. On a larger scale, we found high population differentiation and clear genetic structuring among regions, suggesting that gene flow was restricted by geographical features (mountains separating river systems) for relatively long periods. Our findings of genetic structures based on different spatial conditions elucidated patterns and ranges of historical and contemporary gene movement in a plant species that is persistent in extremely disturbed riparian environments.

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“…At one extreme, passive dispersers are influenced by directional dispersing agents such as ocean currents, river currents or prevailing winds (Watkinson 1985;Pulliam 1988;Holt 1996a;Honnay et al 2001). In rivers, the direction of dispersal is predominantly downstream leading to an accumulation of genetic diversity in populations located in the lower reaches of a river-as discovered for fish (HernandezMartich & Smith 1997) and plant species (Friedman & Stein 1980;Gornall et al 1998). Wind is known to be an important factor for sand dune plants (Keddy 1981) and shifts in temperature isotherms induced by climate change may lead to asymmetric dispersal of species towards the poles and higher altitudes (review by Walther et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Does colonization asymmetry matter in metapopulations?

Vuilleumier

Possingham

2006

Proc. R. Soc. B.

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Despite the considerable evidence showing that dispersal between habitat patches is often asymmetric, most of the metapopulation models assume symmetric dispersal. In this paper, we develop a Monte Carlo simulation model to quantify the effect of asymmetric dispersal on metapopulation persistence. Our results suggest that metapopulation extinctions are more likely when dispersal is asymmetric. Metapopulation viability in systems with symmetric dispersal mirrors results from a mean field approximation, where the system persists if the expected per patch colonization probability exceeds the expected per patch local extinction rate. For asymmetric cases, the mean field approximation underestimates the number of patches necessary for maintaining population persistence. If we use a model assuming symmetric dispersal when dispersal is actually asymmetric, the estimation of metapopulation persistence is wrong in more than 50% of the cases. Metapopulation viability depends on patch connectivity in symmetric systems, whereas in the asymmetric case the number of patches is more important. These results have important implications for managing spatially structured populations, when asymmetric dispersal may occur. Future metapopulation models should account for asymmetric dispersal, while empirical work is needed to quantify the patterns and the consequences of asymmetric dispersal in natural metapopulations.

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Evidence for spatial structure and directional gene flow in a population of an aquatic plant, Potamogeton coloratus

Cited by 29 publications

References 7 publications

Impacts of artificial barriers on the connectivity and dispersal of vascular macrophytes in rivers: A critical review

Impacts of artificial barriers on the connectivity and dispersal of vascular macrophytes in rivers: A critical review

Multiple spatial scale patterns of genetic diversity in riparian populations ofAinsliaea faurieana(Asteraceae) on Yakushima Island, Japan

Does colonization asymmetry matter in metapopulations?

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