scholarly journals Genetic Structure in Neotropical Birds with Different Tolerance To Urbanization

2021 ◽  
Author(s):  
Mauricio Rodríguez-Bardía ◽  
Eric J. Fuchs ◽  
Gilbert Barrantes ◽  
Ruth Madrigal-Brenes ◽  
Luis Sandoval
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Urban Expansion ◽  
Bird Species ◽  
Dispersal Limitation ◽  
Conservation Strategies ◽  
Urban Dweller ◽  
House Wren ◽  
House Wrens ◽  
Genetic Diversity And Structure

Abstract Gene flow in birds can be affected by urbanization depending on natural history traits and adaptability to habitat change. Contrasting results can be expected when comparing species with opposite resilience to urbanization. In this study, we assessed genetic diversity and structure for two bird species, the urban avoider white-eared ground-sparrow, Melozone leucotis, and the urban dweller house wren Troglodytes aedon. We used seven microsatellite loci and sampled five locations with differing levels of urbanization in Costa Rica. We found considerably higher genetic structure in white-eared ground-sparrows than in house wrens. Circuit theory analyses proved a higher isolation from urban resistance for the white-eared ground-sparrow than for house wrens. These results support that urbanization is a significant barrier for gene flow in urban avoiders, in contrast to urban dweller species that showed little to no impact. Differences could be attributed to a higher plasticity in habitat and nesting site preferences in the house wren, and significant dispersal limitation for the white-eared ground-sparrow. These results emphasize the need for conservation strategies towards white-eared ground-sparrows and other urban avoider species whose habitat and connectivity have been reduced by the recent urban expansion.

scholarly journals Genetic structure of Oryza glumaepatula wild rice populations and evidence of introgression from O. sativa in Costa Rica

2015 ◽  
Author(s):  
Eric J Fuchs ◽  
Allan Meneses Martínez ◽  
Amanda Calvo ◽  
Melania Muñoz ◽  
Griselda Arrieta-Espinoza
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Costa Rica ◽  
Genetic Structure ◽  
Wild Species ◽  
Wild Rice ◽  
Wild Rice Species ◽  
Genetic Diversity And Structure ◽  
Diversity Estimates ◽  
Oryza Glumaepatula

Wild crop relatives are an important source of genetic diversity for crop improvement. However, gene flow from cultivated species into wild species may prove detrimental. Introgression may lead to changes in wild species by incorporating alleles from domesticated species, which may increase the likelihood of extinction. The objective of the present study is to analyze how genetic diversity is distributed within and among populations of the wild rice species Oryza glumaepatula in Costa Rica. We also evaluated if there is evidence of introgression between wild rice and commercial varieties of O. sativa since it is cultivated commonly in close proximity to wild rice populations. Individuals from all known O. glumaepatula populations in Costa Rica were collected. With the aid of 455 AFLP markers, we characterized the genetic diversity and structure among seven populations in northern Costa Rica. Given the dominant nature of our markers, Bayesian estimates of genetic structure were used. We also compared genetic diversity estimates between O. glumaepatula individuals and O. sativa commercial rice. Our results show that O. glumaepatula populations in Costa Rica have moderately high levels of genetic diversity, comparable to those found in South American populations. This is likely a result of large population size. Despite the restricted distributions of this wild species, in Costa Rica most populations are composed of several thousand individuals, thus reducing the effects of drift on genetic diversity. Our results also found low but significant structure (\theta=0.03±0.001) among populations that are separated by ~10 Km within a single river. The position of the population along the river did not influence genetic diversity estimates or differences among populations. This river does not have a strong current and meadows or seeds may easily move upstream, thus homogenizing genetic diversity across populations regardless of river position. Ample gene flow through pollen, seeds or detached culms within the same river reduces genetic structure. A Bayesian structure analysis showed that individuals from two populations share a significant proportion of their genomes with O. sativa genome. These results suggest that the low levels of genetic structure found in these populations are likely the result of introgression from cultivated O. sativa populations. These results expose an important biohazard as recurrent hybridization may reduce genetic diversity of this wild rice species. Introgression may transfer commercial traits into the only populations of O. glumaepatula in Costa Rica, which in turn could alter genetic diversity and increase the likelihood of local extinction. These results have important implications for in situ conservation strategies of the only wild populations of O. glumaepatula in Costa Rica.

Conservation Biology

Monteverde ◽  
2000 ◽  
Author(s):  
Nathaniel T. Wheelwright
Keyword(s):  
Conservation Biology ◽  
Bird Species ◽  
House Wren ◽  
Widespread Species ◽  
Brood Parasites ◽  
Colonizing Species ◽  
House Wrens ◽  
Moist Forest ◽  
Population Sizes ◽  
Highland Forests

Each February, when I return to Monteverde to study the reproductive ecology of lauraceous trees, I stay with friends in their farmhouse tucked on the edge of the lower montane moist forest. On my first morning back, I am always eager to listen to the dawn bird chorus. During my most recent visit, I awoke to hear a cacophony of Great-tailed Crackles, a noisy flock of Brown Jays, an exuberant House Wren, and a gang of Bronzed Cowbirds squabbling over spilled grain by the cow barn. Back in 1978, during my first visit, there were no Great-tailed Crackles in Monteverde. Brown Jays had colonized the area, but their flocks were relatively small and restricted to the lower parts of the community. House Wrens, always familiar denizens of Monteverde’s yards and farms, are more abundant today than ever. Once a rarity in Monteverde, Bronzed Cowbirds are now common. Monteverde has changed, and more changes are coming. The rest of Monteverde’s avifauna has undoubtedly felt an impact from the explosive population growth of these bird species. Crackles and jays prey on the eggs, nestlings, and fledglings of other birds; wrens also occasionally destroy other birds’ eggs. Cowbirds are brood parasites. All four species potentially compete with other species for food. Without censuses from earlier years, it is impossible to know how newly colonizing species have affected the fauna and flora of Monteverde. Contributors to this book have provided evidence that various species of animals and plants, especially widespread species of Costa Rica’s lowlands and foothills, have expanded their ranges and increased their population sizes in Monteverde. At the same time, other species are rarer than they used to be only a few decades ago. I used to marvel at the frenzied breeding aggregations of Golden Toads, hold multicolored Harlequin Frogs, and listen to nightly serenades of glass frogs along the Río Guacimal. Most of them no longer exist in Monteverde. In this chapter my goals are to (1) highlight aspects of the biodiversity of Monteverde that are relevant to conservation, (2) give a brief overview of general concepts in conservation biology, (3) discuss conservation problems that are specific to Monteverde and neotropical highland forests, and (4) consider how principles of conservation biology might provide solutions to those problems.

scholarly journals The influence of gene flow and drift on genetic and phenotypic divergence in two species of Zosterops in Vanuatu

2010 ◽  
Vol 365 (1543) ◽  
pp. 1077-1092 ◽  
Author(s):  
Sonya M. Clegg ◽  
Albert B. Phillimore
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Bird Species ◽  
Dispersal Ability ◽  
Phenotypic Divergence ◽  
Genetic Patterns ◽  
Changing Patterns ◽  
Regional Population

Colonization of an archipelago sets the stage for adaptive radiation. However, some archipelagos are home to spectacular radiations, while others have much lower levels of diversification. The amount of gene flow among allopatric populations is one factor proposed to contribute to this variation. In island colonizing birds, selection for reduced dispersal ability is predicted to produce changing patterns of regional population genetic structure as gene flow-dominated systems give way to drift-mediated divergence. If this transition is important in facilitating phenotypic divergence, levels of genetic and phenotypic divergence should be associated. We consider population genetic structure and phenotypic divergence among two co-distributed, congeneric (Genus: Zosterops ) bird species inhabiting the Vanuatu archipelago. The more recent colonist, Z. lateralis , exhibits genetic patterns consistent with a strong influence of distance-mediated gene flow. However, complex patterns of asymmetrical gene flow indicate variation in dispersal ability or inclination among populations. The endemic species, Z. flavifrons , shows only a partial transition towards a drift-mediated system, despite a long evolutionary history on the archipelago. We find no strong evidence that gene flow constrains phenotypic divergence in either species, suggesting that levels of inter-island gene flow do not explain the absence of a radiation across this archipelago.

scholarly journals Clinging to survival: Critically Endangered Chapman's pygmy chameleon Rhampholeon chapmanorum persists in shrinking forest patches

Oryx ◽  
2021 ◽  
pp. 1-6
Author(s):  
Krystal A. Tolley ◽  
Colin R. Tilbury ◽  
Jessica M. da Silva ◽  
Gary Brown ◽  
Yankho Chapeta ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Satellite Imagery ◽  
Critically Endangered ◽  
Forest Loss ◽  
Mitochondrial Marker ◽  
Forest Patches ◽  
Genetic Diversity And Structure ◽  
The Impact

Abstract The Critically Endangered Chapman's pygmy chameleon Rhampholeon chapmanorum is endemic to the low elevation rainforest of the Malawi Hills in southern Malawi. Much of this forest has been converted to agriculture and it was uncertain whether chameleon populations have persisted. We used current and historical satellite imagery to identify remaining forest patches and assess deforestation. We then surveyed forest patches for the presence of this chameleon, and assessed its genetic diversity and structure. We estimated that 80% of the forest has been destroyed since 1984, although we found extant populations of the chameleon in each of the patches surveyed. Differentiation of genetic structure was strong between populations, suggesting that gene flow has been impaired. Genetic diversity was not low, but this could be the result of a temporal lag as well as lack of sensitivity in the mitochondrial marker used. Overall, the impact of forest loss is assumed to have led to a large demographic decline, with forest fragmentation preventing gene flow.

scholarly journals Effects of Landscape Attributes on Campuses Bird Species Richness and Diversity, Implications for Eco-Friendly Urban Planning

2021 ◽  
Vol 13 (10) ◽  
pp. 5558
Author(s):  
Yong Zhang ◽  
Chao Jiang ◽  
Sheng Chen ◽  
Yuanyuan Zhang ◽  
Hui Shi ◽  
...  
Keyword(s):  
Species Richness ◽  
Urban Planning ◽  
Urban Expansion ◽  
Bird Species ◽  
Urban Biodiversity ◽  
Conservation Strategies ◽  
Bird Species Richness ◽  
Buffer Area ◽  
Species Richness And Diversity ◽  
Landscape Attributes

Landscape changes due to urban expansion may severely influence urban biodiversity through direct and indirect effects. Hence, a comprehensive understanding of the urban expansion effects on species diversity is essential for conservation biologists, urban planners, and policymakers to help design more practical and effective conservation strategies. Here, based on monthly bird survey data of 12 university campuses distributed in the center and the Xianlin university town of Nanjing city, we first compared the differences of the campuses bird species richness, Shannon-Wiener, and Simpson indices. Then, we analyzed the effects of a variety of landscape attributes on the campuses bird species richness. Unlike other studies, we also constructed a 2 km buffer area surrounding each campus and analyzed the effects of the landscape attributes of the buffer area on species richness. We found that bird species richness was higher in the campus of Xianlin compared to those in the center. Landscape attributes played an important role on bird species richness, especially for the determinants in the buffer area. Specifically, species richness, Shannon-Wiener, and Simpson indices increased with the increasing area of water and green space both within the campus and the buffer area. Not surprisingly, bird species richness and diversity were more affected by fragmentation of the buffer area, increasing with the aggregation index and decreasing with the splitting index. Our study emphasized that landscape attributes of both campuses and buffer areas determined bird species richness and diversity, offering several practical implications for urban biodiversity maintenance and eco-friendly urban planning.

scholarly journals High genetic diversity and strong genetic structure of Strongyllodes variegatus (Coleoptera: Nitidulidae) demonstrate the genetic mechanism of its distribution in oilseed rape production areas in China

2020 ◽  
Author(s):  
HaiXia Zhan ◽  
ZhongPing Hao ◽  
JingJiang Zhou ◽  
Rui Tang ◽  
LiNi Zhu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Genetics ◽  
Gene Flow ◽  
Genetic Structure ◽  
Oilseed Rape ◽  
Population Genetic ◽  
Distribution Analysis ◽  
Geographical Regions ◽  
Genetic Diversity And Structure ◽  
Production Areas

Abstract Background : Strongyllodes variegatus (Fairmaire) is a major insect pest of oilseed rape in China. Despite its economic importance, the population genetics of this pest contributing to the development of suitable management and control strategies is poorly known. To understand the population genetics and assess the geographical patterns and genetic structure of S. variegates in China. Using mitochondrial DNA cytochrome c oxidase subunit I and cytochrome b region sequences as genetic markers, we analyzed population genetic diversity and structure from 437 individuals collected in 15 S. variegates populations located in different oilseed rape production areas in China. In addition, we estimated the demographic history using neutrality test and mismatch distribution analysis. Results : The high level of genetic diversity was detected among the mtDNA region sequences of S. variegates . The population structure analysis strongly suggested that three genetic and geographical regions occur with limited gene flow. The Mantel test showed that the genetic distance was greatly influenced by geographical distance. The demographic analyses showed that S. variegates experienced population fluctuation during the Pleistocene, which was likely to be related to the climatic changes. Conclusion : Overall, these results demonstrated that the strong population genetic structure of this beetle may attribute to the geographical barriers and subsequently adapt to the regional ecological conditions for the distribution of S. variegates in China. Keywords : Gene flow, Genetic differentiation, Haplotype, Oilseed rape, Population genetic pattern, Strongyllodes variegates

scholarly journals High gene flow maintains wide-range species cohesion in a Neotropical epiphyte (Tillandsia aeranthos, Bromeliaceae)

2020 ◽  
Vol 194 (2) ◽  
pp. 239-252
Author(s):  
Felipe Aoki-Gonçalves ◽  
Marcos Vinicius Dantas De Queiroz ◽  
Thais De Beauclair Guimarães ◽  
Viviana Solís Neffa ◽  
Clarisse Palma-Silva
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Breeding System ◽  
Ecological Data ◽  
Pollination Experiments ◽  
Controlled Pollination ◽  
Wide Range ◽  
Genetic Diversity And Structure ◽  
Assignment Analysis

Abstract Studies of patterns of genetic diversity, genetic structure and ecological data across geographical ranges of species allow us to test hypotheses about the evolutionary responses of organisms to fluctuations in habitat connectivity and availability. Here we present a study aiming to assess genetic diversity, population structure and breeding system across the geographical distribution of a subtropical epiphyte, Tillandsia aeranthos (Bromeliaceae), endemic to the Plata River basin (Pampa biome). Seven nuclear microsatellite markers were genotyped in 203 individuals from 13 localities across Brazil and Argentina and 14 plastid regions were sequenced for a subset of the individuals. Additionally, we performed controlled pollination experiments to discuss correlations between breeding system, genetic diversity and structure in the species. Nuclear diversity levels were high (HE = 0.806, HO = 0.745, allelic richness = 5.860) with no haplotype differentiation detected (c. 9 kpb sequenced). Bayesian assignment analysis, supported by principal coordinate analysis and analysis of molecular variance, show low genetic structure across the studied area (FST = 0.031, P < 0.001). Controlled pollination experiments indicated complete self-incompatibility in all localities analysed. Our results show effective gene flow maintaining low genetic structure between localities for T. aeranthos across an extensive area in the Pampa.

scholarly journals Genetic structure of annual ryegrass (Lolium multiflorum) populations estimated by RAPD

2004 ◽  
Vol 61 (4) ◽  
pp. 407-413 ◽  
Author(s):  
Eduardo Alano Vieira ◽  
Caroline Marques Castro ◽  
Antônio Costa de Oliveira ◽  
Fernando Irajá Félix de Carvalho ◽  
Paulo Dejalma Zimmer ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Diversity Index ◽  
Lolium Multiflorum ◽  
Rio Grande ◽  
Conservation Strategies ◽  
Temperate Climate ◽  
Annual Ryegrass ◽  
Rio Grande Do Sul ◽  
Genetic Diversity And Structure

Annual ryegrass is a temperate climate annual foraging grass, grown mostly in the South of Brazil, especially in the state of Rio Grande do Sul. Despite its importance, little is known about its genetic diversity, both within and among the populations cultivated. This knowledge is of fundamental importance for developing breeding and conservation strategies. The aim of this study was to characterize the genetic diversity and structure of four populations of annual ryegrass. Three of the populations were located in Rio Grande do Sul and the fourth in Uruguay. RAPD markers were used to study the genetic diversity and structure of these populations. Analysis of 375 individuals sampled from the populations, using six RAPD primers, generated a total of 82 amplified bands. They included 73 polymorphic bands (89,02%). The value of the total genetic diversity index obtained, <IMG SRC="/img/revistas/sa/v61n4/22157s1.gif">(0,71) was high, indicating the presence of wide genetic diversity in the four populations. Genetic structure analysis revealed that 98% of total diversity is intrapopulational, whereas interpopulational genetic diversity was only 2%. These results suggest that before these populations separated, they had gone through a period of gene exchange and, even after the separation event, gene frequency stayed at levels similar to the original levels, with no differential selection for these genes in the different cultivation areas.

scholarly journals Population genetic structure and connectivity of a riparian selfing herb Caulokaempferia coenobialis at a fine-scale geographic level in subtropical monsoon forest

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qiong Fu ◽  
Jie Deng ◽  
Min Chen ◽  
Yan Zhong ◽  
Guo-Hui Lu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Population Genetic ◽  
Spatial Genetic Structure ◽  
Complex Mixture ◽  
Conservation Strategies ◽  
Riparian Plants ◽  
Local Populations ◽  
Genetic Diversity And Structure ◽  
Monsoon Forest

Abstract Background Rivers and streams facilitate movement of individuals and their genes across the landscape and are generally recognized as dispersal corridors for riparian plants. Nevertheless, some authors have reported directly contrasting results, which may be attributed to a complex mixture of factors, such as the mating system and dispersal mechanisms of propagules (seed and pollen), that make it difficult to predict the genetic diversity and population structure of riparian species. Here, we investigated a riparian self-fertilizing herb Caulokaempferia coenobialis, which does not use anemochory or zoochory for seed dispersal; such studies could contribute to an improved understanding of the effect of rivers or streams on population genetic diversity and structure in riparian plants. Using polymorphic ISSR and cpDNA loci, we studied the effect at a microgeographic scale of different stream systems (a linear stream, a dendritic stream, and complex transverse hydrological system) in subtropical monsoon forest on the genetic structure and connectivity of C. coenobialis populations across Dinghu Mountain (DH) and Nankun Mountain (NK). Results The results indicate that the most recent haplotypes (DH: H7, H8; NK: h6, h7, h11, h12) are not shared among local populations of C. coenobialis within each stream system. Furthermore, downstream local populations do not accumulate genetic diversity, whether in the linear streamside local populations across DH (H: 0.091 vs 0.136) or the dendritic streamside local populations across NK (H: 0.079 vs 0.112, 0.110). Our results show that the connectivity of local C. coenobialis populations across DH and NK can be attributed to historical gene flows, resulting in a lack of spatial genetic structure, despite self-fertilization. Selfing C. coenobialis can maintain high genetic diversity (H = 0.251; I = 0.382) through genetic differentiation (GST = 0.5915; FST = 0.663), which is intensified by local adaptation and neutral mutation and/or genetic drift in local populations at a microgeographic scale. Conclusion We suggest that streams are not acting as corridors for dispersal of C. coenobialis, and conservation strategies for maintaining genetic diversity of selfing species should be focused on the protection of all habitat types, especially isolated fragments in ecosystem processes.

scholarly journals Genetic structure of Oryza glumaepatula wild rice populations and evidence of introgression from O. sativa in Costa Rica

2015 ◽  
Author(s):  
Eric J Fuchs ◽  
Allan Meneses Martínez ◽  
Amanda Calvo ◽  
Melania Muñoz ◽  
Griselda Arrieta-Espinoza
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Costa Rica ◽  
Genetic Structure ◽  
Wild Species ◽  
Wild Rice ◽  
Wild Rice Species ◽  
Genetic Diversity And Structure ◽  
Diversity Estimates ◽  
Oryza Glumaepatula

Wild crop relatives are an important source of genetic diversity for crop improvement. However, gene flow from cultivated species into wild species may prove detrimental. Introgression may lead to changes in wild species by incorporating alleles from domesticated species, which may increase the likelihood of extinction. The objective of the present study is to analyze how genetic diversity is distributed within and among populations of the wild rice species Oryza glumaepatula in Costa Rica. We also evaluated if there is evidence of introgression between wild rice and commercial varieties of O. sativa since it is cultivated commonly in close proximity to wild rice populations. Individuals from all known O. glumaepatula populations in Costa Rica were collected. With the aid of 455 AFLP markers, we characterized the genetic diversity and structure among seven populations in northern Costa Rica. Given the dominant nature of our markers, Bayesian estimates of genetic structure were used. We also compared genetic diversity estimates between O. glumaepatula individuals and O. sativa commercial rice. Our results show that O. glumaepatula populations in Costa Rica have moderately high levels of genetic diversity, comparable to those found in South American populations. This is likely a result of large population size. Despite the restricted distributions of this wild species, in Costa Rica most populations are composed of several thousand individuals, thus reducing the effects of drift on genetic diversity. Our results also found low but significant structure (\theta=0.03±0.001) among populations that are separated by ~10 Km within a single river. The position of the population along the river did not influence genetic diversity estimates or differences among populations. This river does not have a strong current and meadows or seeds may easily move upstream, thus homogenizing genetic diversity across populations regardless of river position. Ample gene flow through pollen, seeds or detached culms within the same river reduces genetic structure. A Bayesian structure analysis showed that individuals from two populations share a significant proportion of their genomes with O. sativa genome. These results suggest that the low levels of genetic structure found in these populations are likely the result of introgression from cultivated O. sativa populations. These results expose an important biohazard as recurrent hybridization may reduce genetic diversity of this wild rice species. Introgression may transfer commercial traits into the only populations of O. glumaepatula in Costa Rica, which in turn could alter genetic diversity and increase the likelihood of local extinction. These results have important implications for in situ conservation strategies of the only wild populations of O. glumaepatula in Costa Rica.

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