scholarly journals Detecting the Early Genetic Effects of Habitat Degradation in Small Size Remnant Populations of Machilus thunbergii Sieb. et Zucc. (Lauraceae)

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Shuntaro Watanabe ◽  
Yuko Kaneko ◽  
Yuri Maesako ◽  
Naohiko Noma

Habitat degradation caused by human activities has reduced the sizes of many plant populations worldwide, generally with negative genetic impacts. However, detecting such impacts in tree species is not easy because trees have long life spans. Machilus thunbergii Sieb. et Zucc. (Lauraceae) is a dominant tree species of broad-leaved evergreen forests distributed primarily along the Japanese coast. Inland habitats for this species have become degraded by human activities. To investigate the effects of habitat degradation on genetic structure, we compared the genetic diversities of mature and juvenile trees of five M. thunbergii populations around Lake Biwa in Japan. Allelic diversity was influenced by past lineage admixture events, but the effects of forest size were not clear. On the other hand, the inbreeding coefficient of the juvenile stage was higher in small populations, whereas large populations maintained panmictic breeding. Also, the extent of genetic differentiation was greater in juveniles than in mature trees. We detected the early genetic effects of habitat degradation in small, isolated M. thunbergii populations, indicating that habitat degradation increases inbreeding and genetic differentiation between populations.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jorge Palomo-Kumul ◽  
Mirna Valdez-Hernández ◽  
Gerald A. Islebe ◽  
Manuel J. Cach-Pérez ◽  
José Luis Andrade

AbstractWe evaluated the effect of ENSO 2015/16 on the water relations of eight tree species in seasonally dry tropical forests of the Yucatan Peninsula, Mexico. The functional traits: wood density, relative water content in wood, xylem water potential and specific leaf area were recorded during the rainy season and compared in three consecutive years: 2015 (pre-ENSO conditions), 2016 (ENSO conditions) and 2017 (post-ENSO conditions). We analyzed tree size on the capacity to respond to water deficit, considering young and mature trees, and if this response is distinctive in species with different leaf patterns in seasonally dry tropical forests distributed along a precipitation gradient (700–1200 mm year−1). These traits showed a strong decrease in all species in response to water stress in 2016, mainly in the driest site. Deciduous species had lower wood density, higher predawn water potential and higher specific leaf area than evergreen species. In all cases, mature trees were more tolerant to drought. In the driest site, there was a significant reduction in water status, regardless of their leaf phenology, indicating that seasonally dry tropical forests are highly vulnerable to ENSO. Vulnerability of deciduous species is intensified in the driest areas and in the youngest trees.


REINWARDTIA ◽  
2018 ◽  
Vol 17 (2) ◽  
Author(s):  
Asep Sadili ◽  
Kuswata Kartawinata ◽  
Herwasono Soedjito ◽  
Edy Nasriadi Sambas

ADILI, A., KARTAWINATA, K., SOEDJITO, H. & SAMBAS, E. N. 2018. Tree species diversity in a pristine montane forest previously untouched by human activities in Foja Mountains, Papua, Indonesia. Reinwardtia 17(2): 133‒154. ‒‒ A study on structure and composition of the pristine montane forest previously untouched by human activities was conducted at the Foja Mountains in November 2008. We established a one-hectare plot divided into 100 subplots of 10 m × 10 m each. We enumerated all trees with DBH ≥ 10 cm which diameters were measured, heights were estimated and habitats were noted. We recorded 59 species, 42 genera and 27 families, comprising 693 trees with the total basal area (BA) of 41.35 m2/ha. The forest had lower species richness compared to those of lowland forests in Kalimantan, and Sumatra and montane forests in West Java. The Shannon-Wiener’s diversity index was 3.22. Nothofagus rubra (Importance Value, IV=47.89%) and Parinari corymbosa (IV=40.3%) were the dominant species, constituting the basis for designating the forest as the Nothofagus rubra - Parinari corymbosa association. To date, the dominance of N. rubra is unique to the Foja Mountains, as elsewhere in Papua the montane forests were dominated by N. pullei or other species. The species-area curve indicated a minimal area of 5000 m2. On the family level Fagaceae (IV=53.23%), Chrysobalanaceae (IV=40.53%) and Myristicaceae (IV=26.43%) were dominant. Verti-cally the forest consisted of four strata (A–D). In each stratum Nothofagus rubra, Platea latifolia, Parinari corymbosa and Myristica hollrungii were dominant. The diameter class distribution of Nothofagus rubra, Parinari corymbosa and Platea latifolia led us to assume that these species were regenerating well.


2012 ◽  
Vol 99 (7) ◽  
pp. e265-e267 ◽  
Author(s):  
Y. Kaneko ◽  
C. Lian ◽  
S. Watanabe ◽  
K.-i. Shimatani ◽  
H. Sakio ◽  
...  

Genome ◽  
2020 ◽  
Vol 63 (10) ◽  
pp. 493-502
Author(s):  
Sisanda Mayekiso ◽  
Gavin Gouws ◽  
Monica Mwale ◽  
Ofer Gon

Patterns of genetic structure and connectivity of the monotypic cigar wrasse Cheilio inermis within western Indian Ocean (WIO) are poorly understood. Whether the species exists as a single panmictic population across the WIO is unclear. Sequence data were generated from two mitochondrial genes (cytochrome b and ATPase 6) and one nuclear intron (S7 intron I). High levels of haplotype and allelic diversity (h = 0.88–0.98; A = 0.95–0.98), along with low nucleotide diversities were observed across all markers. The pairwise ΦST values indicated differentiation of Tanga from the four WIO localities (Inhaca, Nosy Bé, Gazi, and Shimoni), as well as differentiation between the northernmost WIO localities. AMOVAs indicated high differentiation among defined locality groups, whereas nuclear gene analysis found little differentiation among groups. The observed genetic differentiation in C. inermis could be caused by oceanic barriers, and by limited larval dispersal with the pelagic larvae possibly settling near their parental origin and promoting differentiation.


2016 ◽  
Vol 12 (10) ◽  
pp. 20160620 ◽  
Author(s):  
Jamie Hudson ◽  
Frédérique Viard ◽  
Charlotte Roby ◽  
Marc Rius

Human activities are responsible for the translocation of vast amounts of organisms, altering natural patterns of dispersal and gene flow. Most research to date has focused on the consequences of anthropogenic transportation of non-indigenous species within introduced ranges, with little research focusing on native species. Here, we compared genetic patterns of the sessile marine invertebrate, Ciona intestinalis , which has highly restricted dispersal capabilities. We collected individuals in a region of the species' native range where human activities that are known to facilitate the artificial spread of species are prevalent. Using microsatellite markers, we revealed highly dissimilar outcomes. First, we found low levels of genetic differentiation among sites separated by both short and large geographical distances, indicating the presence of anthropogenic transport of genotypes, and little influence of natural geographical barriers. Second, we found significant genetic differentiation in pairwise comparisons among certain sites, suggesting that other factors besides artificial transport (e.g. natural dispersal, premodern population structure) may be shaping genetic patterns. Taken together, we found dissimilar patterns of population structure in a highly urbanized region that could not be predicted by artificial transport alone. We conclude that anthropogenic activities alter genetic composition of native ranges, with unknown consequences for species' evolutionary trajectories.


2006 ◽  
Vol 87 (1) ◽  
pp. 1-12 ◽  
Author(s):  
EMMANUELLE PORCHER ◽  
TATIANA GIRAUD ◽  
CLAIRE LAVIGNE

The comparison of the genetic differentiation of quantitative traits (QST) and molecular markers (FST) can inform on the strength and spatial heterogeneity of selection in natural populations, provided that markers behave neutrally. However, selection may influence the behaviour of markers in selfing species with strong linkage disequilibria among loci, therefore invalidating this test of detection of selection. We address this issue by monitoring the genetic differentiation of five microsatellite loci (FST) and nine quantitative traits (QST) in experimental metapopulations of the predominantly selfing species Arabidopsis thaliana, that evolved during eight generations. Metapopulations differed with respect to population size and selection heterogeneity. In large populations, the genetic differentiation of neutral microsatellites was much larger under heterogeneous selection than under uniform selection. Using simulations, we show that this influence of selection heterogeneity on FST can be attributable to initial linkage disequilibria among loci, creating stronger genetic differentiation of QTL than expected under a simple additive model with no initial linkage. We found no significant differences between FST and QST regardless of selection heterogeneity, despite a demonstrated effect of selection on QST values. Additional data are required to validate the role of mating system and linkage disequilibria in the joint evolution of neutral and selected genetic differentiation, but our results suggest that FST/QST comparisons can be conservative tests to detect selection in selfing species.


2015 ◽  
Vol 3 (2) ◽  
pp. 01
Author(s):  
G. Martins ◽  
R. L. S. Ferraz ◽  
J. L. Batista ◽  
M. A. Barbosa

<p>Em decorrência de atividades antrópicas exploratórias, tem ocorrido aumento na supressão de espécies arbóreas, refletindo na biodiversidade e equilíbrio dos ecossistemas, reduzindo a população de espécies de abelhas.<strong> </strong>Objetivou-se com este trabalho, fazer um levantamento da ocorrência de árvores, nidificações e espécies de abelhas com intuito de incentivar o plantio de espécimes, principalmente nativos, na área urbana, para que ocorra uma maior proliferação das abelhas indígenas sem ferrão. Para tanto, realizou-se um estudo na Praça Dr. Joaquim Batista na cidade de Jaboticabal, SP. Através de consultas em literatura especializada, identificou-se o número de espécies arbóreas e abelhas sem ferrão, o número e altura média de nidificações, além da coleta de sementes para produção de mudas. Foram identificadas 27 espécies de árvores nativas, 14 exóticas, cinco de abelhas sem ferrão, 37 nidificações, com altura média geral de 2,3 m, além da produção de 20 mudas nativas. A elevada ocorrência de nidificações em plantas nativas e a presença de sementes, demonstram a adaptabilidade destes polinizadores, além de subsidiar a viabilidade da proposta de incentivar o plantio de espécimes, principalmente nativas em área urbana para a proliferação das abelhas indígenas sem ferrão. Estudos complementares podem ser realizados visando educação ambiental nestes locais.</p><p align="center"><strong>Encouraging the planting of native trees in the urban area for proliferation of stingless bees</strong></p><p>As a result of exploratory human activities, there has been an increase in the suppression of tree species, reflecting on biodiversity and ecosystem balance, reducing the population of bee species. The objective of this work, to survey the occurrence of trees, Nest establishment and bee species in order to encourage the planting of species, mostly native, in urban areas, so that there is a higher proliferation of indigenous stingless bees. Therefore, we carried out a study in Dr. Joaquim Batista Square in the city of Jaboticabal, SP. Through consultations in the literature, we identified the number of tree species and stingless bees, the average number and height of Nest establishment, besides the collection of seeds for seedlings. They identified 27 species of native trees, 14 exotic, five of stingless bees, 37 Nest establishment, with overall average height of 2.3 m, in addition to producing 20 native seedlings. The high occurrence of Nest establishment of native plants and the presence of seeds demonstrate the adaptability of these pollinators, in addition to supporting the viability of the proposal to encourage the planting of specimens, especially in urban areas native to the proliferation of indigenous stingless bees. Additional studies can be conducted to environmental education in these places.</p>


2016 ◽  
Vol 47 (2) ◽  
pp. 115 ◽  
Author(s):  
Christiana Ndidi Egbinola

The study investigated the tree species composition along the forest-savanna boundary in Oyo state of Nigeria with the aim of assessing the impact of human activities on the floristic composition. A transect was placed along the study area and species data was collected from quadrats placed in study plots within different study sites. Detrended Correspondence Analysis (DCA) was used to determine vegetation assemblages, while both correlation and the analysis of variance (ANOVA) were used to show the relationship between species in the different study sites. Results of the DCA revealed three species assemblages, an area with only forest species, another with only savanna species and a third with both forest/savanna species. ANOVA results further revealed that within the forest and savanna assemblages, species in mature and successional sites were alike. The study therefore revealed that human activities’ within the region is leading to the establishment of savanna species and an elimination of forest species.


Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 394 ◽  
Author(s):  
Jian-Feng Liu ◽  
Ze-Ping Jiang ◽  
Marcus Schaub ◽  
Arthur Gessler ◽  
Yan-Yan Ni ◽  
...  

Most of our knowledge about forest responses to global environmental changes is based on experiments with seedlings/saplings grown in artificially controlled conditions. We do not know whether this knowledge will allow us to upscale to larger and mature trees growing in situ. In the present study, we used elevation as a proxy of various environmental factors, to examine whether there are ontogenetic differences in carbon and nutrient allocation of two major treeline species (Pinus cembra L. and Larix decidua Mill.) along elevational gradients (i.e., environmental gradient) in the Swiss alpine treeline ecotone (~300 m interval). Young and adult trees grown at the same elevation had similar levels of non-structural carbohydrates (NSCs), total nitrogen (TN), and phosphorus (TP), except for August leaf sugars and August leaf TP in P. cembra at the treeline. We did not detect any interaction between tree age and elevation on tissue concentration of NSCs, TN, and TP across leaf, shoot, and root tissues for both species, indicating that saplings and mature trees did not differ in their carbon and nutrient responses to elevation (i.e., no ontogenetic differences). With respect to carbon and nutrient allocation strategies, our results show that young and adult trees of both deciduous and evergreen tree species respond similarly to environmental changes, suggesting that knowledge gained from controlled experiments with saplings can be upscaled to adult trees, at least if the light is not limited. This finding advances our understanding of plants’ adaptation strategies and has considerable implications for future model-developments.


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