Landscape barriers to pollen and seed flow in the dioecious tropical tree Astronium fraxinifolium in Brazilian savannah

Gene flow studies provide information on gene exchange between populations, which is essential for developing genetic conservation strategies. Such analyses enable a better understanding of the life history and seed and pollen dispersal mechanisms of plant species. In this study, we investigate pollen and seed flow in a regenerant population of the pioneer species Astronium fraxinifolium in an area degraded during the construction of a hydroelectric dam. We mapped, sampled, sexed, and genotyped 386 individuals in the regenerant population (RP), as well as 128 adult trees located along two highways adjacent to the degraded area; one in Mato Grosso do Sul State (MS) and other in São Paulo State (SP). Parentage analyses was carried out for 370 individuals of the RP population, using as putative parents 348 individuals from RP and all 128 individuals sampled in MS and SP. Based on parentage analysis and eight microsatellite loci, our analyses revealed that for individuals of the RP with an identified father (pollen donor), 1.1% of the pollen was dispersed up to 532 m, while for those with an identified mother (seed donor), 0.5% of seeds were dispersed up to 4,782 m. However, a large proportion of pollen (76.5%) and seeds (57%) immigrated from trees outside the sampled populations. Pollen and seeds were dispersed through a pattern of isolation by distance. Genetic diversity was significantly similar between adults of both highway populations and individuals from RP, with significant levels of inbreeding detected only in RP. Our results demonstrate that the nearest trees contributed pollen and seeds for the recovery of the degraded area, indicating reproductive spatial isolation among the sampled populations due to the damming of the river. Such results help to understand the process of regeneration for A. fraxinifolium in regenerant populations to inform strategies for conservation and environmental recovery with this species.

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Economic analysis of rice and common bean production in succession to green manure crops and mecahnical soil decompression in Brazilian Savannah

Revista CERES ◽

10.1590/0034-737x201663030006 ◽

2016 ◽

Vol 63 (3) ◽

pp. 315-322 ◽

Cited By ~ 3

Author(s):

Vagner do Nascimento ◽

Orivaldo Arf ◽

Maria Aparecida Anselmo Tarsitano ◽

Nayara Fernanda Siviero Garcia ◽

Mariele de Souza Penteado ◽

...

Keyword(s):

Common Bean ◽

Green Manure ◽

Cajanus Cajan ◽

Pennisetum Glaucum ◽

Upland Rice ◽

Green Manures ◽

Mato Grosso ◽

Brazilian Savannah ◽

Soil Scarification ◽

Mato Grosso Do Sul

ABSTRACT The previous cultivation of green manures and mechanical soil decompression are options to minimize compaction of the topsoil in no-tilage system (NTS) set in different production systems in the Brazilian Savannah. In addition, it is essential to relate these agricultural practices with the economic benefits generated through the production cycles. The objective of this study was to evaluate economically the effect of sporadic mechanical decompression of the soil and previous cultivation of green manure in the production and net gain margin of upland rice and "winter" common bean, under sprinkler irrigation, in NTS in lowland Brazilian savannah. This study was developed in the 2012/13 harvest and 2013 winter in Selvíria, state of Mato Grosso do Sul, in an clay texture Oxisol in the savanah in the state of Mato Grosso do Sul, in a randomized block design arranged in a 5 x 2 factorial arrangement with four replications. The treatments were a combination of five green manures (fallow (control), Cajanus cajan, Crotalaria juncea, Pennisetum glaucum and Urochloa ruziziensis) with and without mechanical soil scarification. The yields of upland rice and common bean grains were not influenced by the previous green manure cultivation; the upland rice grown in succession to Cajanus cajan in the presence of mechanical soil scarification provided greater increase in grain yield and higher gross margin profit. Beans cultivated in succession to Crotalaria juncea and Pennisetum glaucum in the presence of mechanical soil scarification, followed by rice cultivation, provided greater increases in grain yield and gross profit margins.

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Significant population genetic structure detected for a new and highly restricted species of Atriplex (Chenopodiaceae) from Western Australia, and implications for conservation management

Australian Journal of Botany ◽

10.1071/bt11223 ◽

2012 ◽

Vol 60 (1) ◽

pp. 32 ◽

Cited By ~ 15

Author(s):

Laurence J. Clarke ◽

Duncan I. Jardine ◽

Margaret Byrne ◽

Kelly Shepherd ◽

Andrew J. Lowe

Keyword(s):

Genetic Variation ◽

New Species ◽

Genetic Structure ◽

Western Australia ◽

Sequence Data ◽

Isolation By Distance ◽

Conservation Strategies ◽

New Taxon ◽

Near Surface ◽

Two Populations

Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) is a highly restricted, potentially new species of saltbush, known from only two sites ~30 km apart in central Western Australia. Knowledge of genetic structure within the species is required to inform conservation strategies as both populations occur within a palaeovalley that contains significant near-surface uranium mineralisation. We investigate the structure of genetic variation within populations and subpopulations of this taxon using nuclear microsatellites. Internal transcribed spacer sequence data places this new taxon within a clade of polyploid Atriplex species, and the maximum number of alleles per locus suggests it is hexaploid. The two populations possessed similar levels of genetic diversity, but exhibited a surprising level of genetic differentiation given their proximity. Significant isolation by distance over scales of less than 5 km suggests dispersal is highly restricted. In addition, the proportion of variation between the populations (12%) is similar to that among A. nummularia populations sampled at a continent-wide scale (several thousand kilometres), and only marginally less than that between distinct A. nummularia subspecies. Additional work is required to further clarify the exact taxonomic status of the two populations. We propose management recommendations for this potentially new species in light of its highly structured genetic variation.

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CHEMICAL AND MICROBIOLOGICAL ATTRIBUTES UNDER DIFFERENT SOIL COVER

CERNE ◽

10.1590/01047760201723012228 ◽

2017 ◽

Vol 23 (1) ◽

pp. 19-30 ◽

Cited By ~ 7

Author(s):

Elaine Novak ◽

Laércio Alves Carvalho ◽

Etenaldo Felipe Santiago ◽

Irzo Isaac Rosa Portilho

Keyword(s):

Soil Quality ◽

Private Property ◽

Microbial Biomass Carbon ◽

Principal Component ◽

Basal Respiration ◽

Exchange Capacity ◽

Native Vegetation ◽

Mato Grosso ◽

Environmental Recovery ◽

Short Period

ABSTRACT A challenge for the environmental recovery of degraded areas is the search for soil data. In this process, the microbiological parameters and soil chemicals are potential indicators of soil quality. This study aimed to evaluate soil quality based on microbiological and chemical soil attributes in different areas involving environmental recovery, sugarcane cultivation and remnants of native vegetation located in a rural private property farm in State of Mato Grosso do Sul, Brazil, in Hapludox Eutrophic soil. The microbiological (microbial biomass carbon, basal respiration, microbial quotient and metabolic quotient) and chemical parameters (organic matter, carbon, pH, cationic exchange capacity, sum of bases, potassium, phosphorus, magnesium, calcium, saturation base and potential acidity) were assessed. Data were assessed by variance and multivariate analysis (Principal Component Analysis and cluster analysis). Overall, the results showed highest alteration in the chemical and microbiological characteristics of the soil in sugarcane cultivation area in comparison with other areas. Considering the studied recovery areas, REC1, REC5 and REC7 show chemical and microbiological conditions with most similarity to native vegetation. Despite the short period of the resilience enhancement of environmental recovery areas, the development of vegetation cover and establishment of the microbial community were determined to be important factors for improving soil quality and environmental recovery in several of the areas studied.

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Genetic Diversity and Population Divergence of a Rare, Endemic Grass (Elymus breviaristatus) in the Southeastern Qinghai-Tibetan Plateau

Sustainability ◽

10.3390/su11205863 ◽

2019 ◽

Vol 11 (20) ◽

pp. 5863 ◽

Cited By ~ 2

Author(s):

Qingqing Yu ◽

Qian Liu ◽

Yi Xiong ◽

Yanli Xiong ◽

Zhixiao Dong ◽

...

Keyword(s):

Genetic Diversity ◽

Tibetan Plateau ◽

Isolation By Distance ◽

Genetic Distances ◽

Conservation Strategy ◽

Conservation Strategies ◽

Grass Species ◽

Population Divergence ◽

High Genetic Diversity ◽

Widespread Species

Elymus breviaristatus is a grass species only distributed in the southeast of Qinghai-Tibetan Plateau (QTP), which has suffered from serious habitat fragmentation. Therefore, understanding patterns of genetic diversity within and among natural E. breviaristatus populations could provide insight for future conservation strategies. In this study, sequence-related amplified polymorphism markers were employed to investigate the genetic diversity and hierarchical structure of seven E. breviaristatus populations from QTP, China. Multiple measures of genetic diversity indicated that there is low to moderate genetic variation within E. breviaristatus populations, consistent with its presumed mating system. In spite of its rarity, E. breviaristatus presented high genetic diversity that was equivalent to or even higher than that of widespread species. Bayesian clustering approaches, along with clustering analysis and principal coordinate analysis partitioned the studied populations of E. breviaristatus into five genetic clusters. Differentiation coefficients (Fst, GST, etc.) and AMOVA analysis revealed considerable genetic divergence among different populations. BARRIER analyses indicated that there were two potential barriers to gene flow among the E. breviaristatus populations. Despite these patterns of differentiation, genetic distances between populations were independent of geographic distances (r = 0.2197, p = 0.2534), indicating little isolation by distance. Moreover, despite detecting a common outlier by two methods, bioclimatic factors (altitude, annual mean temperature, and annual mean precipitation) were not related to diversity parameters, indicating little evidence for isolation caused by the environment. These patterns of diversity within and between populations are used to propose a conservation strategy for E. breviaristatus.

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Unrecognized biodiversity in a world’s hotspot: three new species of Melanorivulus (Cyprinodontiformes: Rivulidae) from tributaries of the right bank of the Rio Paraná basin, Brazilian Cerrado

Zoosystematics and Evolution ◽

10.3897/zse.94.24406 ◽

2018 ◽

Vol 94 (2) ◽

pp. 263-280 ◽

Cited By ~ 2

Author(s):

Matheus V. Volcan ◽

Francisco Severo-Neto ◽

Luis Esteban K. Lanés

Keyword(s):

New Species ◽

Species Group ◽

The Body ◽

Conservation Strategies ◽

Distal Margin ◽

Brazilian Cerrado ◽

Mato Grosso ◽

Paraná Basin ◽

The Right ◽

Parana Basin

The genus Melanorivulus presents a wide geographical distribution in the Neotropical region. Among Melanorivulus, the M.pictus species group has currently 18 species distributed in the Brazilian Cerrado, mainly in the upper Rio Paraná basin, with some species occurrences in the upper Rio Araguaia and Tocantins. In the present study, we describe three new Melanorivulus species, belonging to the M.pictus species group from different drainages of the right bank of the Rio Paraná basin in Mato Grosso do Sul state, Brazil. These new species are easily distinguished from the others by their unique colour patterns. Melanorivulusinterruptus is distinguished from all species of the M.pictus group by the presence of oblique chevron-like red bars interrupted, mainly on the midline of the flank in males; while M.ivinhemensis by the yellow colouration of the caudal fin with thin red bars arranged only in the median region of the fin in males. Melanorivulusamambaiensis is distinguished from all species of the M.pictus species group by having an orange anal fin or sometimes more reddish-orange with distal margin grey or dark grey and chevron-like bars along the body, distinctly branched ventrally forming an inverted Y-shape in males. The high diversity of the Melanorivulus species with high levels of endemism demands the development of conservation strategies to avoid the loss of their vulnerable habitats in the Cerrado biome. We expect presence of more species of the M.pictus species group also along the lower reaches of the tributaries of the Rio Paraná. Additionally a dichotomic identification key of the M.pictus species group is provided.

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Integrating population genetics to define conservation units from the core to the edge of Rhinolophus ferrumequinum western range

10.1101/662643 ◽

2019 ◽

Author(s):

Orianne Tournayre ◽

Jean-Baptiste Pons ◽

Maxime Leuchtmann ◽

Raphael Leblois ◽

Sylvain Piry ◽

...

Keyword(s):

Genetic Diversity ◽

Isolation By Distance ◽

Demographic History ◽

Large Population ◽

Conservation Strategies ◽

Conservation Units ◽

Management Units ◽

Rhinolophus Ferrumequinum ◽

Northern France ◽

History Of

AbstractThe greater horseshoe bat (Rhinolophus ferrumequinum) is among the most widespread bat species in Europe but it has experienced severe declines, especially in Northern Europe. This species is listed Near Threatened in the European IUCN Red List of Threatened Animals and it is considered to be highly sensitive to human activities and particularly to habitat fragmentation. Therefore, understanding the population boundaries and demographic history of populations of this species is of primary importance to assess relevant conservation strategies. In this study, we used 17 microsatellite markers to assess the genetic diversity, the genetic structure and the demographic history of R. ferrumequinum colonies in the Western European part of its distribution. We found high levels of genetic diversity and large population size on the European mainland and lower estimates in England and Northern France. Analyses of clustering and isolation by distance showed a barrier effect of the Channel and potentially of the Mediterranean Sea on R. ferrumequinum bat dispersal. Conversely, we could not reveal any gene flow disruption from both sides of the Western Pyrenees. These results provide important information to improve the delineation of R. ferrumequinum management units in its western range. We suggest that a large management unit corresponding to the European mainland population must be considered. Particular attention should be given to mating territories as they seem to play a key role in maintaining the high levels of genetic mixing between colonies. Smaller management units corresponding to English and Northern France colonies must also be implemented. These insular or peripheral colonies could be at higher risk of extinction in a near future.

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Fine-Scale Spatial Genetic Structure with Nonuniform Distribution of Individuals

Genetics ◽

10.1093/genetics/148.2.905 ◽

1998 ◽

Vol 148 (2) ◽

pp. 905-919

Author(s):

Agnès Doligez ◽

Claire Baril ◽

Hélène I Joly

Keyword(s):

Genetic Structure ◽

Local Density ◽

Isolation By Distance ◽

Spatial Genetic Structure ◽

Pollen Dispersal ◽

Continuous Distribution ◽

Fine Scale ◽

Independent Locus ◽

Continuous Plant ◽

Input Variables

Abstract This paper presents the first theoretical study of spatial genetic structure within nonuniformly distributed continuous plant populations. A novel individual-based model of isolation by distance was constructed to simulate genetic evolution within such populations. We found larger values of spatial genetic autocorrelations in highly clumped populations than in uniformly distributed populations. Most of this difference was caused by differences in mean dispersal distances, but aggregation probably also produced a slight increase in spatial genetic structure. Using an appropriate level of approximation of the continuous distribution of individuals in space, we assessed the potential effects of density, seed and pollen dispersal, generation overlapping, and overdominance selection at an independent locus, on fine-scale genetic structure, by varying them separately in a few particular cases with extreme clumping. When selfing was allowed, all these input variables influenced both aggregation and spatial genetic structure. Most variations in spatial genetic structure were closely linked to variations in clumping and/or local density. When selfing was not allowed, spatial genetic structure was lower in most cases.

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Spatial genetic structure in the very rare and species-rich Picea chihuahuana tree community (Mexico)

Silvae Genetica ◽

10.1515/sg-2014-0020 ◽

2014 ◽

Vol 63 (1-6) ◽

pp. 149-158 ◽

Cited By ~ 9

Author(s):

C. Z. Quiñones-Pérez ◽

S. L. Simental-Rodríguez ◽

C. Sáenz-Romero ◽

J. P. Jaramillo-Correa ◽

C. Wehenkel

Keyword(s):

Genetic Structure ◽

Populus Tremuloides ◽

Isolation By Distance ◽

Spatial Genetic Structure ◽

Strong Support ◽

Forest Tree ◽

Conservation Strategies ◽

Fine Scale ◽

Ecological Features ◽

Tree Community

Abstract In natural plant populations, the spatial genetic structure (SGS) is occasionally associated with evolutionary and ecological features such as the mating system, individual fitness, inbreeding depression and natural selection of the species of interest. The very rare Mexican P. chihuahuana tree community covers an area no more than 300 ha and has been the subject of several studies concerning its ecology and population genetics. The overall aim of most of these studies has been to obtain data to help design preservation and conservation strategies. However, analysis of the fine-scale SGS in this special forest tree community has not yet been conducted, which might help enrich the above mentioned conservation programs. In this study, we examined the SGS of this community, mostly formed by P. chihuahuana Martínez, Pinus strobiformis Ehrenberg ex Schlechtendah, Pseudotsuga menziesii (Mirb.) Franco, and Populus tremuloides Michx, in 14 localities at both the fine and large scales, with the aim of obtaining a better understanding of evolutionary processes. We observed a non-significant autocorrelation in fine-scale SGS, suggesting that the genetic variants of all four tree species are randomly distributed in space within each sampled plot of 50 x 50 m. At the larger scale, the autocorrelation was highly significant for P. chihuahuana and P. menziesii, probably as a result of insufficient gene flow due to the extreme population isolation and small sizes. For these two species our results provided strong support for the theory of isolation by distance.

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Isolation-by-distance within naturally established populations of European beech (Fagus sylvatica)

Botany ◽

10.1139/b09-049 ◽

2009 ◽

Vol 87 (8) ◽

pp. 791-798 ◽

Cited By ~ 21

Author(s):

Igor J. Chybicki ◽

Magdalena Trojankiewicz ◽

Andrzej Oleksa ◽

Artur Dzialuk ◽

Jaroslaw Burczyk

Keyword(s):

Genetic Structure ◽

Fagus Sylvatica ◽

Spatial Clustering ◽

Scale Effects ◽

Isolation By Distance ◽

Spatial Genetic Structure ◽

Pollen Dispersal ◽

Distance Effect ◽

European Beech ◽

Biparental Inbreeding

In plants, the magnitude of seed and pollen dispersal plays a pivotal role in shaping genetic structure of populations. Restricted dispersal of genes can stimulate the increase of inbreeding as well as spatial clustering of relatives. These phenomena are explained by the theory of isolation-by-distance. Because of its biology, European beech ( Fagus sylvatica L.) seems to be susceptible to isolation-by-distance. However, to date fine-scale effects, including biparental inbreeding and a spatial genetic structure are not fully recognized for this species. In this study, two populations of European beech were investigated, both representing a dense beech forest, typical for Central Europe. Using nine microsatellite markers and a recently developed method, we found a significant level of biparental inbreeding in both populations. Spatial autocorrelation analysis revealed that both populations exhibit clustering of related individuals up to 40 m. The observed spatial genetic structure fit well to the log-linear regression model. Thus, results confirmed our hypothesis of the presence of the isolation-by-distance effect. Furthermore, based on these results we inferred a dispersal mode, both for seeds and pollen; in particular, seed dispersal was 10–100 times more restricted than pollen flow, although a significant portion of short-distance pollinations responsible for biparental inbreeding cannot be excluded.

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Population structure and parentage analysis of black poplar along the Morava River

Canadian Journal of Forest Research ◽

10.1139/x06-003 ◽

2006 ◽

Vol 36 (5) ◽

pp. 1067-1076 ◽

Cited By ~ 40

Author(s):

Markéta Pospíšková ◽

Ivana Šálková

Keyword(s):

Genetic Structure ◽

Populus Deltoides ◽

Spatial Genetic Structure ◽

Glacial Refugia ◽

Parentage Analysis ◽

Hybrid Poplars ◽

Adult Trees ◽

Nuclear Microsatellite ◽

Dispersal Distances ◽

Morava River

Twelve nuclear microsatellite markers were used to assess the population genetic structure of the riparian pioneer tree species Populus nigra L. along the Morava River in the Czech Republic. Parentage analysis of 30 seedlings was performed to examine the extent of hybridization between P. nigra and introduced hybrid poplars and to determine the distances of pollen and seed movement. Additionally, spatial genetic structure was analysed and gene dispersal was estimated indirectly. In spite of the limited size of our studied population (65 adult trees), the apparent overall genetic diversity was high (expected heterozygosity He = 0.82) and comparable to the known diversity of P. nigra in southern Europe, where its glacial refugia were located. Introgression of Populus deltoides Bartr. ex Marsh. genes to P. nigra was confirmed, since 13% of tested seedlings descended from a Populus ×canadensis Moench female. The results of parentage analysis showed that a low percentage (20%) of offspring originated from parents located outside the study site. Dispersal distances for pollen and seeds movement ranged from 10 to 230 m and from 163 to 370 m, respectively. The study revealed significant spatial genetic structure (regression slope 0.0158), which was probably caused by limited gene flow.

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