Hawkmoth Pollination Facilitates Long-distance Pollen Dispersal and Reduces Isolation Across a Gradient of Land-use Change

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.

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Ecological and Environmental Effects of Estuarine Wetland Loss Using Keyhole and Landsat Data in Liao River Delta, China

Remote Sensing ◽

10.3390/rs13020311 ◽

2021 ◽

Vol 13 (2) ◽

pp. 311

Author(s):

Hongyan Yin ◽

Yuanman Hu ◽

Miao Liu ◽

Chunlin Li ◽

Jiujun Lv

Keyword(s):

Heavy Metal ◽

Land Use ◽

Land Use Change ◽

Ecological Risk ◽

Potential Ecological Risk ◽

Wetland Loss ◽

Ecological Effects ◽

Paddy Fields ◽

Suitable Habitat ◽

Estuarine Wetland

An estuarine wetland is an area of high ecological productivity and biodiversity, and it is also an anthropic activity hotspot area, which is of concern. The wetlands in estuarine areas have suffered declines, which have had remarkable ecological impacts. The land use changes, especially wetland loss, were studied based on Keyhole and Landsat images in the Liao River delta from 1962 to 2016. The dynamics of the ecosystem service values (ESVs), suitable habitat for birds, and soil heavy metal potential ecological risk were chosen to estimate the ecological effects with the benefit transfer method, synthetic overlaying method, and potential ecological risk index (RI) method, respectively. The driving factors of land use change and ecological effects were analyzed with redundancy analysis (RDA). The results showed that the built-up area increased from 95.98 km2 in 1962 to 591.49 km2 in 2016, and this large change was followed by changes in paddy fields (1351.30 to 1522.39 km2) and dry farmland (189.5 to 294.14 km2). The area of wetlands declined from 1823.16 km2 in 1962 to 1153.52 km2 in 2016, and this change was followed by a decrease in the water area (546.2 to 428.96 km2). The land use change was characterized by increasing built-up (516.25%), paddy fields (12.66%) and dry farmland (55.22%) areas and a decline in the wetland (36.73%) and water areas (21.47%) from 1962–2016. Wetlands decreased by 669.64 km2. The ESV values declined from 6.24 billion US$ to 4.46 billion US$ from 1962 to 2016, which means the ESVs were reduced by 19.26% due to wetlands being cultivated and the urbanization process. The area of suitable habitat for birds decreased by 1449.49 km2, or 61.42% of the total area available in 1962. Cd was the primary soil heavy metal pollutant based on its concentration, accumulation, and potential ecological risk contribution. The RDA showed that the driving factors of comprehensive ecological effects include wetland area, Cd and Cr concentration, river and oil well distributions. This study provides a comprehensive approach for estuarine wetland cultivation and scientific support for wetland conservation.

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Camelina (Camelina sativa L. Crantz) Crop Performance, Insect Pollinators, and Pollen Dispersal in the Northeastern US

10.1101/756619 ◽

2019 ◽

Author(s):

Richard Rizzitello ◽

Chuan-Jie Zhang ◽

Carol Auer

Keyword(s):

Gene Flow ◽

Honey Bees ◽

Pollen Dispersal ◽

Camelina Sativa ◽

Genetically Engineered ◽

Oilseed Crop ◽

Crop Failure ◽

Long Distance ◽

Insect Visitation ◽

Pollinating Insects

AbstractCamelina sativa (camelina) is an oilseed crop in the Brassicaceae that has been genetically engineered for the production of biofuels, dietary supplements, and other industrial compounds. Cultivation in North America is both recent and limited, so there are gaps in knowledge regarding yield, weed competition, and pollen-mediated gene flow. For these experiments, camelina ‘SO-40’ was grown for three years without weed control. Spring-sown camelina was harvested at 80-88 days with ∼1200 growing degree days (GDD) with yields of 425-508 kg/hectare. Camelina yields were the same with or without weeds, showing competitive ability in low-management conditions. Crop failure in 2015 was associated with delayed rainfall and above-average temperatures after seeding. Camelina flowers attracted pollinating insects from the Hymenoptera, Diptera, Lepidoptera, and Coleoptera. Hymenoptera included honey bees (Apis melifera), mining bees (Andrenidae), sweat bees (Halictidae), bumble bees (Bombus spp.) and leaf cutter bees (Megachilidae). Insect visitation on camelina flowers was associated with modest increases in seed yield. Honey bees comprised 28-33% of all pollinators and were shown to carry camelina pollen on their legs. Air sampling showed that wind-blown pollen was present at low concentrations at 9 m beyond the edges of the field. These experiments demonstrated for the first time that camelina pollen dispersal could occur through honey bees or wind, although bee activity would likely be more significant for long-distance gene flow.

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Sporadic Genetic Connectivity among Small Insular Populations of the Rare Geoendemic Plant Caulanthus amplexicaulis var. barbarae (Santa Barbara Jewelflower)

Journal of Heredity ◽

10.1093/jhered/esz029 ◽

2019 ◽

Vol 110 (5) ◽

pp. 587-600

Author(s):

A Millie Burrell ◽

Jeffrey H R Goddard ◽

Paul J Greer ◽

Ryan J Williams ◽

Alan E Pepper

Keyword(s):

Gene Flow ◽

Genetic Connectivity ◽

Effective Population ◽

Evolutionary Potential ◽

Isolated Populations ◽

Long Distance ◽

Population Sizes ◽

History Of ◽

Small Set ◽

Nuclear Microsatellite

Abstract Globally, a small number of plants have adapted to terrestrial outcroppings of serpentine geology, which are characterized by soils with low levels of essential mineral nutrients (N, P, K, Ca, Mo) and toxic levels of heavy metals (Ni, Cr, Co). Paradoxically, many of these plants are restricted to this harsh environment. Caulanthus ampexlicaulis var. barbarae (Brassicaceae) is a rare annual plant that is strictly endemic to a small set of isolated serpentine outcrops in the coastal mountains of central California. The goals of the work presented here were to 1) determine the patterns of genetic connectivity among all known populations of C. ampexlicaulis var. barbarae, and 2) estimate contemporary effective population sizes (Ne), to inform ongoing genomic analyses of the evolutionary history of this taxon, and to provide a foundation upon which to model its future evolutionary potential and long-term viability in a changing environment. Eleven populations of this taxon were sampled, and population-genetic parameters were estimated using 11 nuclear microsatellite markers. Contemporary effective population sizes were estimated using multiple methods and found to be strikingly small (typically Ne < 10). Further, our data showed that a substantial component of genetic connectivity of this taxon is not at equilibrium, and instead showed sporadic gene flow. Several lines of evidence indicate that gene flow between isolated populations is maintained through long-distance seed dispersal (e.g., >1 km), possibly via zoochory.

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Adding landscape genetics and individual traits to the ecosystem function paradigm reveals the importance of species functional breadth

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1619271114 ◽

2017 ◽

Vol 114 (48) ◽

pp. 12761-12766 ◽

Cited By ~ 21

Author(s):

Antonio R. Castilla ◽

Nathaniel S. Pope ◽

Megan O’Connell ◽

María F. Rodriguez ◽

Laurel Treviño ◽

...

Keyword(s):

Gene Flow ◽

Seed Production ◽

Critical Role ◽

Pollen Dispersal ◽

Plant Size ◽

Dispersal Ability ◽

Floral Display ◽

Long Distance ◽

Pollinator Community ◽

Local Plant

Animal pollination mediates both reproduction and gene flow for the majority of plant species across the globe. However, past functional studies have focused largely on seed production; although useful, this focus on seed set does not provide information regarding species-specific contributions to pollen-mediated gene flow. Here we quantify pollen dispersal for individual pollinator species across more than 690 ha of tropical forest. Specifically, we examine visitation, seed production, and pollen-dispersal ability for the entire pollinator community of a common tropical tree using a series of individual-based pollinator-exclusion experiments followed by molecular-based fractional paternity analyses. We investigate the effects of pollinator body size, plant size (as a proxy of floral display), local plant density, and local plant kinship on seed production and pollen-dispersal distance. Our results show that while large-bodied pollinators set more seeds per visit, small-bodied bees visited flowers more frequently and were responsible for more than 49% of all long-distance (beyond 1 km) pollen-dispersal events. Thus, despite their size, small-bodied bees play a critical role in facilitating long-distance pollen-mediated gene flow. We also found that both plant size and local plant kinship negatively impact pollen dispersal and seed production. By incorporating genetic and trait-based data into the quantification of pollination services, we highlight the diversity in ecological function mediated by pollinators, the influential role that plant and population attributes play in driving service provision, and the unexpected importance of small-bodied pollinators in the recruitment of plant genetic diversity.

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Pollen dispersal and gene flow by pollen in Araucaria angustifolia

Australian Journal of Botany ◽

10.1071/bt02037 ◽

2003 ◽

Vol 51 (3) ◽

pp. 309 ◽

Cited By ~ 19

Author(s):

V. A. Sousa ◽

H. H. Hattemer

Keyword(s):

Gene Flow ◽

Pollen Dispersal ◽

Pollen Grains ◽

Physical Characteristics ◽

Araucaria Angustifolia ◽

Effective Population ◽

Pollen Dispersion ◽

Biological Studies ◽

Seed Dispersion ◽

Dispersion Patterns

Araucaria angustifolia (Bert.) O.Ktze. is an economically important tree in southern Brazil. Indiscriminate exploitation is threatening this species with extinction. Conservation programs are urgently needed to save the remaining forest, and such programs must be guided by biological studies that genetically characterise the remaining populations. Pollen and seed dispersion patterns determine the distance of gene flow and directly influence genetic structure and effective population size. A. angustifolia is a wind-pollinated dioecious tree. For pollen-dispersal airflow, physical characteristics of pollen grain, such as size and shape, must be considered. The aim of this work was to determine the homogeneity of effective pollen clouds as well as to infer the physical characteristics of pollen. The homogeneity of pollen clouds of A. angustifolia was assessed for 70 trees of natural population in Brazil. Analysis of genetic variability and differentiation of the effective pollen clouds detected high diversity at the MDH-B and 6-PGDH-B loci. Heterogeneity G-tests indicated pollen pool heterogeneity in four of seven examined loci (GOT-B, PGM-A, SKDH-B and 6-PGDH-B). The pollen grains measured 61.50 μm. The floating rate ranged from 12.02 to 18.98 cm s–1. The physical characteristics of the pollen suggest that pollen dispersion is likely to be limited.

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Sexual Reproduction and Gene Flow in the Pine Pathogen Dothistroma septosporum in British Columbia

Phytopathology ◽

10.1094/phyto-04-10-0121 ◽

2011 ◽

Vol 101 (1) ◽

pp. 68-76 ◽

Cited By ~ 35

Author(s):

A. L. Dale ◽

K. J. Lewis ◽

B. W. Murray

Keyword(s):

British Columbia ◽

Gene Flow ◽

Sexual Reproduction ◽

Mating Type ◽

Random Mating ◽

Long Distance Dispersal ◽

Long Distance ◽

Data Set ◽

Haplotypic Diversity ◽

Dothistroma Septosporum

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.

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Genetic variation in the emblematic Puya raimondii (Bromeliaceae) from Huascarán National Park, Peru

Cropp Breeding and Applied Biotechnology ◽

10.1590/s1984-70332013000100008 ◽

2013 ◽

Vol 13 (1) ◽

pp. 67-74 ◽

Cited By ~ 3

Author(s):

Claudia Teresa Hornung-Leoni ◽

Victoria Sosa ◽

June Simpson ◽

Katia Gil

Keyword(s):

Genetic Diversity ◽

Cluster Analysis ◽

Genetic Variation ◽

Gene Flow ◽

Genetic Variability ◽

National Park ◽

Conservation Strategies ◽

Long Distance Dispersal ◽

Long Distance ◽

Mountain Systems

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

Marine and Freshwater Research ◽

10.1071/mf07202 ◽

2008 ◽

Vol 59 (9) ◽

pp. 761 ◽

Cited By ~ 16

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.

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On the persistence and dispersal of transantarctic Hepaticae

Canadian Journal of Botany ◽

10.1139/b79-271 ◽

1979 ◽

Vol 57 (20) ◽

pp. 2179-2225 ◽

Cited By ~ 34

Author(s):

Rudolf M. Schuster

Keyword(s):

Gene Flow ◽

Southern Hemisphere ◽

Short Range ◽

Distribution Patterns ◽

Disjunct Distribution ◽

Long Distance Dispersal ◽

Long Distance ◽

Disjunct Populations ◽

Geological Background

The dispersal of a considerable number, if not the vast majority, of southern hemisphere Hepaticae chiefly belonging to "old" families and suborders can be visualized as resulting primarily from short-range or "step-wise" dispersal, as part of structural communities, before the final disassembly of the presently fragmented Gondwanaland. Often with the disruption of gene flow, disjunct populations of once continuously distributed Gondwanalandic taxa have undergone speciation, in most cases as physical disruption occurred. Significant relict and disjunct distribution patterns for 21 hepatic taxa are mapped and discussed. A discussion of (i) rate of speciation and genus formation, (ii) efficiency of long-distance dispersal, and (iii) the geological background is presented with the purpose of explaining the origins of antipodal distribution patterns within the Hepaticae.

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