scholarly journals Human-mediated dispersal of seeds over long distances

2008 ◽  
Vol 276 (1656) ◽  
pp. 523-532 ◽  
Author(s):  
Matthias C Wichmann ◽  
Matt J Alexander ◽  
Merel B Soons ◽  
Stephen Galsworthy ◽  
Laura Dunne ◽  
...  
Keyword(s):  
Mechanistic Models ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Mechanistic Modelling ◽  
Wide Range ◽  
Primary Vector ◽  
Dispersal Events ◽  
Dispersal Kernels ◽  
Vector Wind ◽  
Primary Dispersal

Human activities have fundamental impacts on the distribution of species through altered land use, but also directly by dispersal of propagules. Rare long-distance dispersal events have a disproportionate importance for the spread of species including invasions. While it is widely accepted that humans may act as vectors of long-distance dispersal, there are few studies that quantify this process. We studied in detail a mechanism of human-mediated dispersal (HMD). For two plant species we measured, over a wide range of distances, how many seeds are carried by humans on shoes. While over half of the seeds fell off within 5 m, seeds were regularly still attached to shoes after 5 km. Semi-mechanistic models were fitted, and these suggested that long-distance dispersal on shoes is facilitated by decreasing seed detachment probability with distance. Mechanistic modelling showed that the primary vector, wind, was less important as an agent of long-distance dispersal, dispersing seeds less than 250 m. Full dispersal kernels were derived by combining the models for primary dispersal by wind and secondary dispersal by humans. These suggest that walking humans can disperse seeds to very long distances, up to at least 10 km, and provide some of the first quantified dispersal kernels for HMD.

ARE LONG-DISTANCE DISPERSAL EVENTS IN PLANTS USUALLY CAUSED BY NONSTANDARD MEANS OF DISPERSAL?

Ecology ◽  
2003 ◽  
Vol 84 (8) ◽  
pp. 1945-1956 ◽  
Author(s):  
S. I. Higgins ◽  
R. Nathan ◽  
M. L. Cain
Keyword(s):  
Long Distance Dispersal ◽  
Long Distance ◽  
Dispersal Events

scholarly journals The global distribution ofBanana bunchy top virusreveals little evidence for frequent recent, human-mediated long distance dispersal events

2015 ◽  
Vol 1 (1) ◽  
pp. vev009 ◽  
Author(s):  
Daisy Stainton ◽  
Darren P. Martin ◽  
Brejnev M. Muhire ◽  
Samiuela Lolohea ◽  
Mana’ia Halafihi ◽  
...  
Keyword(s):  
Global Distribution ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Dispersal Events

Do lowland habitats represent barriers to dispersal for a rainforest mayfly, Bungona narilla, in south-east Queensland?

2008 ◽  
Vol 59 (9) ◽  
pp. 761 ◽  
Author(s):  
Alison J. McLean ◽  
Daniel J. Schmidt ◽  
Jane M. Hughes
Keyword(s):  
Gene Flow ◽  
Aquatic Insect ◽  
Restricted Gene Flow ◽  
Long Distance Dispersal ◽  
Genetic Structuring ◽  
Long Distance ◽  
Heterogeneous Landscapes ◽  
Insect Populations ◽  
Dispersal Events ◽  
The Relationship

Long-distance dispersal might be an important mechanism for the maintenance of aquatic insect populations in heterogeneous landscapes. However, these events can be difficult to measure by direct observation because the techniques can be time-consuming, expensive and technically difficult. When dispersal results in gene flow within and between populations, patterns of variation can be detected by genetic methods. The levels of population genetic structuring and the relationship between gene flow and geographical distance were assessed in the mayfly species Bungona narilla (Harker, 1957) in rainforest streams in south-east Queensland that are separated by lowland habitats. An analysis of molecular variance based on mitochondrial DNA data, using a fragment of the cytochrome oxidase I gene, revealed significant differentiation between regions, suggesting that maternal gene flow was restricted. A nested clade analysis revealed patterns of historical (contiguous) range expansions and recent restricted gene flow along with some long-distance dispersal events. Our analyses have shown that populations of B. narilla are significantly structured throughout the species range in south-east Queensland and that the low elevation habitats separating the northern and southern populations are restricting gene flow to some extent.

scholarly journals Trade of commercial potting substrates: A largely overlooked means of the long-distance dispersal of plants

2021 ◽  
Author(s):  
Judit Sonkoly ◽  
Attila Takács ◽  
Attila Molnár V. ◽  
Péter Török
Keyword(s):  
Plant Species ◽  
Large Scale ◽  
Long Distance Dispersal ◽  
Viable Seed ◽  
Long Distance ◽  
Ecological Processes ◽  
Number Of Species ◽  
Seed Content ◽  
Wide Range ◽  
Viable Seeds

AbstractAlthough long-distance dispersal (LDD) events are considered to be rare and highly stochastic, they are disproportionately important and drive several large-scale ecological processes. The realisation of the disproportionate importance of LDD has led to an upsurge in studies of this phenomenon; yet, we still have a very limited understanding of its frequency, extent and consequences. Humanity intentionally spreads a high number of species, but a less obvious issue is that it is associated with the accidental dispersal of other plant species. Although the global trade of potted plants and horticultural substrates is capable of dispersing large quantities of propagules, this issue has hardly been studied from an ecological point of view. We used the seedling emergence method to assess the viable seed content of different types of commercial potting substrates to answer the following questions: (i) In what richness and density do substrates contain viable seeds? (ii) Does the composition of substrates influence their viable seed content? and (iii) Are there common characteristics of the species dispersed this way? We detected altogether 438 seedlings of 66 taxa and found that 1 litre of potting substrate contains an average of 13.27 seeds of 6.24 species, so an average 20-litre bag of substrate contains 265 viable seeds. There was a high variability in the seed content of the substrates, as substrates containing cattle manure contained a substantially higher number of species and seeds than substrates without manure. Based on this, this pathway of LDD is an interplay between endozoochory by grazing livestock and accidental human-vectored dispersal, implying that the diet preference of grazing animals largely determines the ability of a plant species to be dispersed this way. According to our results, potting substrates can disperse large quantities of seeds of a wide range of plant species, moreover, these dispersal events occur on very long distances in almost all cases. We conclude that this kind of human-vectored LDD may have complex effects on plant populations and communities; however, as this dispersal pathway is largely understudied and has hardly been considered as a type of LDD, its consequences are still largely unknown and further studies of the issue are of great importance.

scholarly journals Estimating dispersal kernels using genetic parentage data

2016 ◽  
Author(s):  
Michael Bode ◽  
David Williamson ◽  
Hugo Harrison ◽  
Nick Outram ◽  
Geoffrey P. Jones
Keyword(s):  
Reef Fish ◽  
Reef Fishes ◽  
Common Source ◽  
Density Dependent Mortality ◽  
Wide Range ◽  
Conservation Genetic ◽  
Dispersal Events ◽  
The Relationship ◽  
Dispersal Kernels ◽  
Power Analyses

AbstractDispersal kernels are the standard method for describing and predicting the relationship between dispersal strength and distance. Statistically-fitted dispersal kernels allow observations of a limited number of dispersal events to be extrapolated across a wider landscape, and form the basis of a wide range of theories and methods in ecology, evolution and conservation. Genetic parentage data are an increasingly common source of dispersal information, particularly for species where dispersal is difficult to observe directly. It is now routinely applied to coral reef fish, whose larvae disperse over many kilometers and are too small to follow directly. However, it is not straightforward to estimate dispersal kernels from parentage data, and existing methods each have substantial limitations. Here we develop and proof a new statistical estimator for fitting dispersal kernels to parentage data, applying it to simulated and empirical datasets of reef fish parentage. The method incorporates a series of factors omitted in previous methods: the partial sampling of adults and juveniles on sampled reefs; the existence of unassigned dispersers from unsampled reefs; and post-settlement processes (e.g., density dependent mortality) that follow dispersal but precede parentage sampling. Power analyses indicate that the highest levels of sampling currently used for reef fishes is sufficient to fit accurate dispersal kernels. Sampling is best distributed equally between adults and juveniles, and over more than ten populations. Importantly, we show that accounting for unsampled or unassigned individuals – including adult individuals on partially-sampled and unsampled patches – is essential for a precise and unbiased estimate of dispersal.

Phylogeny and Biogeography of Acaena (Rosaceae) and its Relatives: Evidence of Multiple Long-Distance Dispersal Events Across the Globe

2021 ◽  
Vol 46 (4) ◽  
pp. 998-1010
Author(s):  
Javier Jauregui-Lazo ◽  
Daniel Potter
Keyword(s):  
South Africa ◽  
New Zealand ◽  
Southern Hemisphere ◽  
Phylogenetic Analyses ◽  
Strong Support ◽  
Disjunct Distribution ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Biogeographic Patterns ◽  
Dispersal Events

Abstract— Acaena (Rosaceae) is the most complex and ecologically variable genus in Sanguisorbinae. Although it has been the subject of several taxonomic treatments, the largest phylogenetic analysis to date only sampled a small fraction of the total global diversity (five to seven out of 45 to 50 species). This study included most of the species to elucidate the phylogenetic relationships of Acaena and biogeographic patterns in Sanguisorbinae. Phylogenetic analyses of non-coding nuclear (ITS region) and chloroplast (trnL-F) DNA sequence markers using maximum likelihood and Bayesian analyses suggested that Acaena is a paraphyletic group with species of Margyricarpus and Tetraglochin nested within it. We identified strong support for eight subclades that are geographically or taxonomically structured. Nevertheless, the species-level relationships within subclades are still uncertain, which may be due to rapid diversification and lack of informative characters in the markers used. Sanguisorbinae, a primarily Southern Hemisphere clade, exhibits a classic Gondwana disjunct distribution. This current distribution is explained primarily by eight long-distance dispersal events. Our results suggested that Sanguisorbinae split into Cliffortia and Acaena around 13.6 mya. While Cliffortia diversified in southern South Africa, Acaena experienced several migration events in the Southern Hemisphere. Our estimation of the ancestral range suggested that Acaena likely originated in South Africa, followed by migration and subsequent diversification into southern South America. From there, the genus migrated to New Zealand, throughout the Andes, and to tropical areas in Central America, reaching as far north as California. Chile and New Zealand are the main sources of propagules for dispersal as well as the greatest diversity for the genus. The evolutionary relationships of species in Acaena combine a history of rapid diversifications, long-distance dispersals, and genetic variation within some taxa. Further research should be undertaken to clarify the infraspecific classification of A. magellanica.

scholarly journals Climate-driven vicariance and long-distance dispersal explain the Rand Flora pattern in the liverwort Exormotheca pustulosa (Marchantiophyta)

2020 ◽  
Vol 130 (3) ◽  
pp. 480-496
Author(s):  
Ana Sofia Bartolomeu Rodrigues ◽  
Anabela Martins ◽  
César Augusto Garcia ◽  
Cecília Sérgio ◽  
Ron Porley ◽  
...  
Keyword(s):  
Late Miocene ◽  
Divergence Time ◽  
Western Mediterranean ◽  
Cape Verde ◽  
Eastern Africa ◽  
Disjunct Distribution ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Divergence Time Estimates ◽  
Dispersal Events

Abstract The ‘Rand flora’ is a biogeographical disjunction which refers to plant lineages occurring at the margins of the African continent and neighbouring oceanic archipelagos. Here, we tested whether the phylogeographical pattern of Exormotheca pustulosa Mitt. was the result of vicariance induced by past climatic changes or the outcome of a series of recent long-distance dispersal events. Two chloroplast markers (rps4-trnF region and psbA-trnH spacer) and one nuclear marker (ITS2) were analysed. Phylogenetic and phylogeographical relationships were inferred as well as divergence time estimates and ancestral areas. Exormotheca possibly originated in Eastern Africa during the Late Oligocene/Early Miocene while Exormotheca putulosa diversified during the Late Miocene. Three main E. pustulosa groups were found: the northern Macaronesia/Western Mediterranean, the South Africa/Saint Helena and the Cape Verde groups. The major splits among these groups occurred during the Late Miocene/Pliocene; diversification was recent, dating back to the Pleistocene. Climate-driven vicariance and subsequent long-distance dispersal events may have shaped the current disjunct distribution of E. pustulosa that corresponds to the Rand Flora pattern. Colonization of Macaronesia seems to have occurred twice by two independent lineages. The evolutionary history of E. pustulosa populations of Cape Verde warrants further study.

scholarly journals Genotypes of Rhizophora Propagules From a Non-mangrove Beach Provide Evidence of Recent Long-Distance Dispersal

2021 ◽  
Vol 2 ◽  
Author(s):  
Magdalene N. Ngeve ◽  
Nico Koedam ◽  
Ludwig Triest
Keyword(s):  
Genetic Research ◽  
Relative Difference ◽  
Source Population ◽  
Long Distance Dispersal ◽  
Long Distance ◽  
Propagule Dispersal ◽  
Adult Trees ◽  
Southern Cameroon ◽  
Source Populations ◽  
Dispersal Events

Dispersal plays a crucial role in the connectivity of established mangrove populations and in species range dynamics. As species ranges shift in response to climate change, range expansions can occur from incremental short-distance dispersal events and from stochastic long-distance dispersal events. Most population genetic research dealt with historically accumulated events though evidence of actual propagule dispersal allows to estimate genotypic features and origin of founders. In this study, we aim to disentangle a contemporary dispersal event. Using microsatellite markers, we genotyped 60 Rhizophora racemosa drift propagules obtained on a bare unforested coastal area in southern Cameroon, estimated their relationship to 109 adult trees from most proximate sites (which were 3–85 km away), and assessed their relative difference with 873 trees of major mangrove areas (> 300 km) along the Cameroonian coastline. Proximate mangrove populations were considered as potential source populations in assignment tests. However, drift propagules could not be assigned to any of the Cameroonian mangrove sites and were genetically isolated from Cameroonian populations. Drift propagules showed higher levels of genetic diversity and private alleles giving a higher relatedness to each other than to any putative source population. Chloroplast sequences were used to confirm the identity of drift propagules as R. racemosa. We postulate that a complex interaction of ocean currents, estuarine geomorphology, and tidal patterns explain drift propagule dispersal to an area. Most likely the investigated cohort of propagules originated from more southern mangrove areas of the West African range beyond the Cameroonian border. This study unraveled the allelic, genetic, and genotypic features of stranded propagules following a stochastic long-distance dispersal. Transboundary dispersal of these propagules highlights the need for intergovernmental efforts in the management of biodiversity.

scholarly journals Psoroma capense and P. esterhuyseniae (Pannariaceae), two new alpine species from South Africa

2020 ◽  
Vol 52 (5) ◽  
pp. 345-352
Author(s):  
Arve Elvebakk ◽  
Soon Gyu Hong ◽  
Chae Haeng Park ◽  
Teppo Rämä
Keyword(s):  
South Africa ◽  
Secondary Compounds ◽  
Western Cape ◽  
Long Distance Dispersal ◽  
Western Cape Province ◽  
Long Distance ◽  
Closely Related Species ◽  
Alpine Species ◽  
Recent Collection ◽  
Dispersal Events

AbstractThe new species Psoroma capense and P. esterhuyseniae are described from four alpine localities in the Western Cape Province of South Africa and are the only known Psoroma species from Africa. The specimens were all collected from moist sites near watercourses, on cool and mostly south-facing cliffs. Psoroma capense resembles P. tenue in gross morphology but differs in the ascending thallus squamules, lack of secondary compounds and short-ellipsoid to ovoid ascospores. However, a phylogenetic analysis involving the markers ITS, nucLSU, mtSSU and Mcm7, comparing the only recent collection of P. capense with previously published sequences, shows that it belongs to the P. hypnorum lineage, with no known, closely related species. Psoroma esterhuyseniae resembles P. hypnorum but has subglobose to short-ellipsoid ascospores without apical perispore extensions. The two species are thought to have evolved from one or two long-distance dispersal events during the Pleistocene.

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