scholarly journals Sex-biased dispersal patterns of a social passerine: complementary approaches and evidence for a role of spatial scale

2019 ◽  
Vol 128 (3) ◽  
pp. 592-602 ◽  
Author(s):  
Jianqiang Li ◽  
Lei Lv ◽  
Pengcheng Wang ◽  
Yong Wang ◽  
Ben J Hatchwell ◽  
...  

Abstract Animal dispersal patterns have important implications for many biological processes, but the measurement of dispersal is challenging and often requires the use of complementary approaches. In this study, we investigated the local-scale sex-biased dispersal pattern in a social bird, the black-throated tit (Aegithalos concinnus), in central China. Spatial genetic autocorrelation analyses suggested that significant fine-scale genetic structure existed in males but not in females. Mark–recapture analyses of ringed individuals also showed that female offspring were more dispersive than male offspring, supporting genetic evidence of local female-biased dispersal. These results were contrary to a previous finding of male-biased long-distance dispersal in this species that was based on analyses of gene flow across the species range in China. This implies that the species might potentially have a scale-dependent dispersal strategy, with females frequently dispersing further than males at the local level, but with a proportion of males occasionally dispersing over long distances and contributing more to gene flow at a larger geographical scale. Long-distance dispersal by male black-throated tits might be induced by competition for resources or by unfavourable environmental conditions, warranting further investigation, but our findings increase the evidence that geographical scale is an important factor to be considered when investigating animal dispersal patterns.

2020 ◽  
Vol 108 (1) ◽  
Author(s):  
A. Kreitschitz ◽  
E. Haase ◽  
S. N. Gorb

AbstractMyxodiaspory (formation of mucilage envelope around seeds and fruits) is a common adaptation to dry habitats known in many families of Angiosperms. The mucilage envelope of some seeds seems to be also a unique morphological adaptation which protects myxospermatic diaspores while passing through the bird’s digestive system. To evaluate the protective potential of mucilage, we fed the diaspores of seven plant species (representing three different mucilage types and three species of non-mucilaginous plants) to pigeons, Columba livia domestica. Twenty-four hours later, we collected the droppings of pigeons and examined a total of 18,900 non-destroyed diaspores to check for mucilage presence and germination ability. Out of all the examined diaspores, 4.5% were mucilaginous seeds. Among them, the highest number (12.2–13.5%) of viable diaspores belonged to the hemicellulosic type of mucilage (from Plantago species). Only 3.7% of germinating diaspores with pectic mucilage (Linum usitatissimum) were collected, and no seeds representing cellulosic mucilage (e.g., Ocimum basilicum). For non-mucilaginous plants, we collected only a few individual seeds (0.1% out of 8100 seeds used). We noted that the mucilaginous seeds found in the droppings were able to germinate; however, the germination ability was generally smaller in comparison to the control (i.e., not digested) seeds. Our results revealed that the presence of mucilage envelope has an impact on diaspore dispersal and survivability. With our experiments, we demonstrated for the first time that the mucilage envelope, especially of the non-cellulosic type, supports endozoochory. We also showed that non-mucilaginous seeds can be occasionally dispersed via endozoochory and are able to germinate. The results of our studies can explain the ways of plants distribution at a small, local scale as well as in long-distance dispersal, e.g., between islands or even continents.


1996 ◽  
Vol 9 (2) ◽  
pp. 169 ◽  
Author(s):  
SWL Jacobs ◽  
KL Wilson

Patterns in the distribution of Australasian species of freshwater aquatic plants were sought, to determine whether vicariance, distance dispersal, local speciation, or a mixture of these could best explain the distribution. The distribution was recorded from 10 regions of Australasia that include sizeable areas of wetland: Papua New Guinea, Cape York Peninsula, south-east Queensland, eastern New South Wales, Victoria, Tasmania, New Zealand, northern Northern Territory, the Kimberley, and south-west Western Australia. Matrices of 553 species by 10 regions, 139 genera by 10 regions, and 56 families by 10 regions were analysed using hierarchical fusion, nearest neighbour and ordination techniques. The results indicate that there are two distinct elements in the aquatic flora, tropical and temperate. The diffuse boundary between these two climatic zones could be interpreted as a barrier in the sense used in definitions of vicariance. There is little effective spread between tropical and temperate areas but, within each of these climatic zones, the species are mobile and many spread reasonably readily between regions, provided suitable habitats and dispersal opportunities are available. Where geographic barriers to distance dispersal have been great then these may become as important as the climatic barrier. This is demonstrated, at least in part, by the differences between some of the generic and species dendrograms. Local speciation (not shown by our PATN analyses because of the endemic species being ignored in them) has been important where some primarily aquatic genera have proliferated when conditions have been suitable. Local speciation has occurred in cosmopolitan aquatic genera that have presumably arrived in regions via long distance dispersal. The significance of bird migration and dispersal patterns are discussed. The aquatic flora of the monsoon tropics has evolved mainly from long distance dispersal but with significant local speciation in some genera such as Nymphoides, Utricularia, Nymphaea and Vallisneria. The pattern of distribution was compared with those recorded from other ecologically defined groups such as the Australian arid and alpine floras.


2004 ◽  
Vol 82 (6) ◽  
pp. 835-840 ◽  
Author(s):  
Jordi Figuerola ◽  
Andy J Green ◽  
Katrina Black ◽  
Beth Okamura

Waterbirds have been proposed as important vectors for the passive dispersal of those aquatic invertebrates and plants that lack a capacity for active dispersal between isolated water bodies. We analysed the frequency of internal transport of bryozoan propagules (statoblasts) by waterbirds in Doñana, Spain, by examining their presence in the intestines and ceca of dead birds and analysing the role of different aspects of gut characteristics in explaining variation in the presence/absence and abundance of statoblasts. Of the 228 samples examined, 7.9% presented intact statoblasts of Plumatella fungosa (Pallas, 1768), Plumatella emarginata Allman, 1844, and two unidentified Plumatella species. For a given bird species, individuals with heavier gizzards and shorter ceca had a lower incidence and abundance of statoblasts in the lower gut. Grit mass and intestine length were unrelated to the presence or abundance of statoblasts. Our results suggest that waterbirds frequently transport bryozoans on a local scale, with lighter gizzards and longer ceca favouring such transport. Lighter gizzards are likely to destroy fewer propagules before they reach the lower gut. Species and individuals with longer ceca are particularly good candidates for long-distance dispersal of bryozoans, given the longer passage time of propagules that enter the ceca.


2019 ◽  
Vol 104 (3) ◽  
pp. 495-511 ◽  
Author(s):  
Krissa A. Skogen ◽  
Rick P. Overson ◽  
Evan T. Hilpman ◽  
Jeremie B. Fant

Land-use change is among the top drivers of global biodiversity loss, which impacts the arrangement and distribution of suitable habitat for species. Population-level effects include increased isolation, decreased population size, and changes to mutualistic and antagonistic interactions. However, the extent to which species are impacted is determined by life history characteristics including dispersal. In plants, mating dynamics can be changed in ways that can negatively impact population persistence if dispersal of pollen and/or seed is disrupted. Long-distance dispersal has the potential to buffer species from the negative impacts of land-use change. Biotic vectors of long-distance dispersal have been less frequently studied, though specific taxa are known to travel great distances. Here, we describe population genetic diversity and structure in a sphingophilous species that is experiencing habitat fragmentation through land-use change, Oenothera harringtonii W. L. Wagner, Stockh. & W. M. Klein (Onagraceae). We use 12 nuclear and four plastid microsatellite markers and show that pollen dispersal by hawkmoths drives high gene flow and low population differentiation despite a range-wide gradient of land-use change and habitat fragmentation. By separating the contributions of pollen and seed dispersal to gene flow, we show that most of the genetic parameters are driven by hawkmoth-facilitated long-distance pollen dispersal, but populations with small, effective population sizes experience higher levels of relatedness and inbreeding. We discuss considerations for conservation efforts for this and other species that are pollinated by long-distance dispersers.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5035 ◽  
Author(s):  
Matthew J. Mogle ◽  
Scott A. Kimball ◽  
William R. Miller ◽  
Richard D. McKown

Terrestrial tardigrades, commonly known as “water bears”, are part of a phylum of microscopic, aquatic invertebrates famous for cryptobiosis and space travel, but little is known about their modes of dispersal on Earth. Wind is assumed, but not truly demonstrated, to be the major method of global dispersal. Yet, some water bear distribution patterns cannot be explained by patterns of prevailing winds. Mammals and birds have been proposed as potential animal vectors. Importantly, most nearctic-neotropical migrant birds move north and south, with many crossing the equator, whereas prevailing winds move west to east or east to west but do not cross the equator. When multiplied by billions of birds over tens of millions of years, if the ectozoochory of tardigrades by birds is true then both regional and intercontinental patterns can be better explained. To test for the potential role of birds in tardigrade dispersal, the nests of 10 species for birds were examined. Seventy percent of nests were positive for tardigrades, demonstrating that some birds are in a position for transference. The carcasses of eight birds (six species) found dead from window strikes and a Sandhill Crane (Grus canadensis) found dead during routine surveys were also examined. Of the birds examined, 66% yielded tardigrades from two classes, three orders, and five species, including juveniles, adults, and eggs, suggesting that many bird species are potential vectors for many species of tardigrades. Our data support the hypothesis of avian-mediated long distance dispersal of tardigrades and provide evidence that further investigation is warranted.


2011 ◽  
Vol 101 (1) ◽  
pp. 68-76 ◽  
Author(s):  
A. L. Dale ◽  
K. J. Lewis ◽  
B. W. Murray

Dothistroma septosporum has caused a serious needle blight epidemic in the lodgepole pine forests in northwest British Columbia over the past several years. Although ascocarps had been observed in British Columbia, nothing was known about the contribution of sexual reproduction, gene flow and long-distance dispersal to the epidemic. Amplified fragment length polymorphism and mating-type markers in 19 sites were used to generate population and reproductive data. Overall, evidence suggests a mixed mode of reproduction. Haplotypic diversity was high, with 79 unique and 56 shared haplotypes (possible clones) identified from 192 fungal isolates. Overall, mating-type segregation did not differ significantly from 1:1; however, random mating was rejected in most populations in the index of association and parsimony tree-length permutation analyses using the full data set and, when using clone-corrected data sets, more of the smaller populations showed random mating. Two of the smaller populations consistently showed random mating for both tests using both clone-corrected and noncorrected data. High gene flow is suggested by no differentiation between 14 of the 19 sites, several of which came from young plantations where the pathogen was not likely present prior to the current outbreak. The remaining five sites showed some level of divergence, possibly due to historic separation and endemic pathogen populations. Results indicate a high evolutionary potential and long-distance dispersal in this pathogen, important to consider in future forest management.


2013 ◽  
Vol 13 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Claudia Teresa Hornung-Leoni ◽  
Victoria Sosa ◽  
June Simpson ◽  
Katia Gil

Puya raimondii, the giant Peruvian and Bolivian terrestrial bromeliad, is an emblematic endemic Andean species well represented in Huascarán National Park in Peru. This park is the largest reserve of puna (high altitude plateau) vegetation. The objective of this study is to report on genetic variation in populations of P. raimondii from Huascarán and neighboring areas. AFLP profiles with four selective primer combinations were retrieved for 60 individuals from different zones. Genetic variability was estimated and a total of 172 bands were detected, of which 79.1% were polymorphic loci. The results showed genetic differentiation among populations, and gene flow. A cluster analysis showed that individuals of P. raimondii populations located in different mountain systems could be grouped together, suggesting long distance dispersal. Thus, conservation strategies for P. raimondii have to take into account exchange between populations located far apart in distance in order to preserve the genetic diversity of this showy species.


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