The hypothesis of hydrochorous dissemination of populations of conifers

Sannikov, S. N.; Sannikova, N. S.

doi:10.1134/s1067413607020014

Cited by 10 publications

(4 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For species relying exclusively on hydrochory, patterns of genetic relatedness can reflect the constraints imposed by the network architecture, with high connectivity among populations situated along the same stream, but isolation among populations in different catchments (Prentis & Mather, 2008; but see Waser, Vickery & Price, 1982). Secondly, since hydrochory has a high capacity for long‐distance propagule dispersal compared to other dispersal modes (Cain et al , 2000; Sannikov & Sannikova, 2007), hydrochory can connect distant populations resulting in larger effective population sizes (Waser et al , 1982). Thirdly, since hydrochory in streams is generally unidirectional, and downstream populations may receive more immigrants than upstream ones, a higher genetic diversity may accumulate in receiving populations.…”

Section: Discussionmentioning

confidence: 99%

“…The ability of plants to disperse their propagules long distances is important for their survival under current constraints of landscape fragmentation and climate change. Hydrochory more often results in long‐distance propagule dispersal than other dispersal modes (Cain et al , 2000; Boedeltje et al , 2003; Sannikov & Sannikova, 2007). This is because propagules can move for long periods of time, then strand and become re‐dispersed in several episodes.…”

Section: Pathwaymentioning

confidence: 99%

See 1 more Smart Citation

The role of hydrochory in structuring riparian and wetland vegetation

et al. 2010

View full text Add to dashboard Cite

Hydrochory, or the passive dispersal of organisms by water, is an important means of propagule transport, especially for plants. During recent years, knowledge about hydrochory and its ecological consequences has increased considerably and a substantial body of literature has been produced. Here, we review this literature and define the state of the art of the discipline. A substantial proportion of species growing in or near water have propagules (fruits, seeds or vegetative units) able to disperse by water, either floating, submerged in flowing water, or with the help of floating vessels. Hydrochory can enable plants to colonize sites out of reach with other dispersal vectors, but the timing of dispersal and mechanisms of establishment are important for successful establishment. At the population level, hydrochory may increase the effective size and longevity of populations, and control their spatial configuration. Hydrochory is also an important source of species colonizing recruitment-limited riparian and wetland communities, contributing to maintenance of community species richness. Dispersal by water may even influence community composition in different landscape elements, resulting in landscape-level patterns. Genetically, hydrochory may reduce spatial aggregation of genetically related individuals, lead to high gene flow among populations, and increase genetic diversity in populations receiving many propagules. Humans have impacted hydrochory in many ways. For example, dams affect hydrochory by reducing peak flows and hence dispersal capacity, altering the timing of dispersal, and by presenting physical barriers to dispersal, with consequences for riverine plant communities. Hydrochory has been inferred to be an important vector for the spread of many invasive species, but there is also the potential for enhancing ecosystem restoration by improving or restoring water dispersal pathways. Climate change may alter the role of hydrochory by modifying the hydrology of water-bodies as well as conditions for propagule release and plant colonization.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Pathwaymentioning

confidence: 99%

The role of hydrochory in structuring riparian and wetland vegetation

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Hydrochory plays an important role in the vegetation structure of the riparian community (Defina & Peruzzo, 2010), and has been shown to increase species richness (Jansson, Zinko, Merritt, & Nilsson, 2005). In addition, it is one of the most efficient dispersal mechanisms, since propagules can establish near their source or travel long distances and therefore reach a greater number of sites (Cain, Milligan, & Strand, 2000; Sannikov & Sannikova, 2007; Waser, Vickery, & Price, 1982). This becomes very important when the environment is fragmented, since dispersal via flowing water can enable the seeds to travel from one fragment to another, influencing regeneration and the genetic structure of populations (Kudoh, Shimamura, Takayama, & Whigham, 2006; Monette & Markwith, 2012; Su, Polvi, Lind, Pilotto, & Nilsson, 2019).…”

Section: Introductionmentioning

confidence: 99%

Effect of the grass Leersia hexandra on the dispersal, seed germination, and establishment of Pachira aquatica seedlings

2020

View full text Add to dashboard Cite

In wetlands, hydrochory is one of the main mechanisms of seed dispersal and there is often synchrony between propagule production and the flood season. Different sources of disturbance can prevent seed dispersal to suitable sites, and if environmental conditions are not adequate for germination and seedling establishment, recruitment will be limited, affecting succession. We worked in a disturbed tropical freshwater swamp where the native grass Leersia hexandra has dominated open areas, creating a grass matrix that surrounds patches of swamp forest. Leersia grows vigorously, forming cushions of dry matter that cover the soil, forming a potential obstacle to seed dispersal. We asked whether the vegetative growth of this grass prevents the entry and dispersal of seeds of the tropical swamp tree Pachira aquatica, thwarting seed germination and seedling establishment, and arresting succession. We set up transects in the grass matrix in two zones: close to the river (R) and bordering the tree patches or fragments (F). We quantified tree seed and seedling presence, survival and growth in situ and experimentally introduced seeds and seedlings in the field and monitored seed germination and the survival and growth of their seedlings, as well as that of transplanted seedlings. There was a negative relationship between the number of seeds and established seedlings, and the distance to river or fragment (r = −0.86, p < 0.001 for zone R; and r = −0.77, p < 0.001 for zone F) and with the grass cushion (r = −0.68, p = 0.005 for zone R; and r = −0.66, p = 0.007 for zone F); the grass creating a barrier to dispersal. When seeds were sown after clearing the grass cushion, germination success was high, so this stage is not limited. The transplanted seedlings had better survival and a greater final height than the seedlings of the sown seeds. Grass cover had a negative effect on both types of seedlings. Seedling survival rates were inversely related to grass cover, showing that seedlings overgrown by grass had low survival rates. Flooding is a stress factor for seedlings and produced mortality, in addition to the effects of the grass. Together, the field survey and the experiment show that succession is being arrested in two ways: (1) by limiting seed dispersal because the grass cushion slows the dispersal and penetration of seeds into the vegetation; and (2) by limiting seedling establishment because the grass competes for space and light. Our results show that even where the grass is native, slower growing, seed‐dependent species may struggle to compete and establish. If grass cover is increasing, these swamps are very vulnerable to a decrease in area because it is very difficult for them to regenerate naturally.

show abstract

“…Hydrochory, or the passive dispersal of organisms by water, is an important means of propagule transport, especially for riparian, aquatic, and wetland systems (Andersson, Nilsson, & Johansson, ; Goodson, Gurnell, Angold, & Morrissey, ; Merritt & Wohl, ). Dispersal via water has a high potential for long‐distance seed dispersal, contributing to large‐scale patterns of species distributions within catchments (Cain, Milligan, & Strand, ; Nilsson, Brown, Jansson, & Merritt, ; Sannikov & Sannikova, ). The movements of waterborne seeds typically involve two phases, that is, primary and secondary dispersals (Chambers & MacMahon, ; Koch, Ailstock, Booth, Shafer, & Magoun, ).…”

Section: Introductionmentioning

confidence: 99%

Floatability and a semiempirical model for resuspension thresholds of hydrochorous seeds

2018

View full text Add to dashboard Cite

Floatability and incipient motion of seeds are the key indicators in primary and secondary dispersal during hydrochory, respectively. Floatability could prolong the time for seeds' survival in water and thereby extend the distance of primary dispersal. Seeds that were deposited but did not germinate may be resuspended and transported by currents farther until permanently stranded. This study aimed to describe and predict the dispersal patterns and movements of seeds with these 2 indicators under static and dynamic water conditions that correspond to the 2 aforementioned dispersal phases. The physical properties and hydrodynamic characteristics of seeds from 3 angiosperm species were used to study the floatability and resuspension thresholds of hydrochorous seeds. Floatability quantified by the number of seeds remaining buoyant varies among the 3 species, implicating their differing capabilities of primary dispersal. Resuspension thresholds of settled seeds were quantified by critical currents (shear velocities) that move seeds at rest on the bed sediment. On the basis of a model of nonuniform sand and collected experimental data, we proposed a model suitable for incipient motion of seeds from the bed. This model can be applied in the evaluation of secondary dispersal potential under different flow conditions. The preliminary research on the movements of seeds in water helps elucidate and determine species distribution and establishment. These factors are important in dispersal ecology.

show abstract

The hypothesis of hydrochorous dissemination of populations of conifers

Cited by 10 publications

References 4 publications

The role of hydrochory in structuring riparian and wetland vegetation

The role of hydrochory in structuring riparian and wetland vegetation

Effect of the grass Leersia hexandra on the dispersal, seed germination, and establishment of Pachira aquatica seedlings

Floatability and a semiempirical model for resuspension thresholds of hydrochorous seeds

Contact Info

Product

Resources

About