There is growing attention given to gene flow between crops and the wild relatives as global landscapes have been rapidly converted into agricultural farm fields over the past century. Crop-to-wild introgression may advance the extinction risks of rare plants through demographic swamping and/or genetic swamping. Malus sieversii, the progenitor of the apple, is exclusively distributed along the Tien Shan mountains. Habitat fragmentation and hybridization between M. sieversii and the cultivated apples have been proposed to be the causal mechanism of the accelerated extinction risk. We examined the genetic diversity pattern of eleven wild and domesticated apple populations and assessed the gene flow between M. sieversii and the cultivated apples in Kazakhstan using thirteen nuclear microsatellite loci. On average, apple populations harbored fairly high within-population diversity, whereas population divergences were very low suggesting likely influence of human-mediated dispersal. Assignment results showed a split pattern between the cultivated and wild apples and frequent admixture among the apple populations. Coupled with the inflated contemporary migration rates, the admixture pattern might be the signature of increased human intervention within the recent past. Our study highlighted the prevalent crop to wild gene flow of apples occurring in Kazakhstan, proposing an accelerated risk of genetic swamping.
Previous studies on the chloroplast genome in Clematis focused on the chloroplast structure within Anemoneae. The chloroplast genomes of Cleamtis were sequenced to provide information for studies on phylogeny and evolution. Two Korean endemic Clematis chloroplast genomes (Clematis brachyura and C. trichotoma) range from 159,170 to 159,532 bp, containing 134 identical genes. Comparing the coding and non-coding regions among 12 Clematis species revealed divergent sites, with carination occurring in the petD-rpoA region. Comparing other Clematis chloroplast genomes suggested that Clematis has two inversions (trnH-rps16 and rps4), reposition (trnL-ndhC), and inverted repeat (IR) region expansion. For phylogenetic analysis, 71 protein-coding genes were aligned from 36 Ranunculaceae chloroplast genomes. Anemoneae (Anemoclema, Pulsatilla, Anemone, and Clematis) clades were monophyletic and well-supported by the bootstrap value (100%). Based on 70 chloroplast protein-coding genes, we compared nonsynonymous (dN) and synonymous (dS) substitution rates among Clematis, Anemoneae (excluding Clematis), and other Ranunculaceae species. The average synonymoussubstitution rates (dS)of large single copy (LSC), small single copy (SSC), and IR genes in Anemoneae and Clematis were significantly higher than those of other Ranunculaceae species, but not the nonsynonymous substitution rates (dN). This study provides fundamental information on plastid genome evolution in the Ranunculaceae.
Abies nephrolepis is a climate-vulnerable species that inhabits high mountains in the Baekdu–Daegan range and is distributed along the southern limit line in South Korea, making it suitable for climate change research. This study aimed to observe spatial distribution changes according to scenarios using species distribution models for Abies nephrolepis, analyze the relationship between various environmental factors and Abies nephrolepis density, and contribute to the future conservation and management of subalpine coniferous forests. We conducted a field survey to identify the growth environment of Abies nephrolepis and observed potentially suitable habitats for Abies nephrolepis based on location information obtained through the survey. We also analyzed the relationship between the density of Abies nephrolepis and various environmental factors using multiple linear regression models. Based on the field survey results, most Abies nephrolepis natural habitats in South Korea showed an unstable form. Vulnerability analysis examining the influence of climate change showed that most of these habitats would be affected. We found that various biological factors were significantly related to the density of Abies nephrolepis (diameter at breast height, DBH ≥ 6 cm) and young tree density (stems/ha). We confirmed that species diversity and rock exposure variables had a relatively high impact. Clarifying the relationship between the density of Abies nephrolepis and various environmental factors can provide new insights for setting future restoration directions.
Clematis, a widely distributed genus in Ranunculaceae, is one of the most difficult groups of taxa in the family from a taxonomic point of view. A comprehensive study on achene morphology and the anatomy of 19 taxa of Clematis from Korea was carried out using scanning electron and light microscopy to evaluate the taxonomic significance of achene characters. Clematis achenes are elliptical, obovate or fusiform in shape, light yellow or brown to black in color and completely or sparsely covered with hairs. The permanent style is elongated and plumose in all the studied taxa except C. brachyura. We found that the size, indument, permanent style, surface sculpture, shape in cross-section, and nature and thickness of the exocarp, and endocarp were valuable achene features for species delimitation and may contribute to the unraveling of the taxonomic problems in the genus Clematis. One-way analysis of variance (ANOVA) indicated that the quantitative achene variables among the species were highly significant (p < 0.001). Principal component analyses based on seven quantitative characters and UPGMA (unweighted pair-group method with arithmetic mean) analysis based on seven quantitative and 18 qualitative characters also signify the utility of achene features for taxonomic discriminations of the Clematis taxa within the genus. Similar to other morphological characters in the genus Clematis, achene morphological and anatomical characters with the limited taxonomic value alone cannot be expected to resolve the infrageneric relationships but certain achene features combined with other morphological features could be useful as an alternative means of determining the infrageneric relationships within the genus.
22 August 2024 in Science of The Total Environment
Northern temperate coniferous forests serve as crucial connectors between boreal and temperate forests, yet they are vulnerable to various stressors such as climate change and human activities. Severe drought poses a significant threat to plant species within these forests, prompting recent research into its impacts. However, many studies lack explicit definitions of post-disturbance vegetation processes and fail to identify potential interactions with disturbance factors, necessitating comprehensive discussions. This study examines the effects of drought on tree growth patterns of the main dominant species in northern temperate regions: Abies nephrolepis and Picea jezoensis, along with two commonly associated Betula ermanii, and Quercus mongolica. Additionally, new disturbance factors in forests inhabited by these species (A. nephrolepis and P. jezoensis) were evaluated based on community classification. The study sites were located in the Mt. Baekdu (Changbai) and South Korea regions, which are positioned at the southern limit of the phytogeographical patterns of target species. Results indicate that A. nephrolepis and P. jezoensis exhibit high levels of recovery and resilience, while B. ermanii and Q. mongolica demonstrate high resistance. Species-specific responses align with drought intensity, with resistance, recovery, and resilience decreasing notably with increasing pre-drought radial growth. South Korean forests, the invasion of the vine species Tripterygium regelii after the death of A. nephrolepis in the overstory vegetation threatens the regeneration of new trees. However, certain environmental factors, such as high rock exposure and dense overstory canopy, limit vine invasion. Based on the results, pre-drought radial growth emerges as a key determinant in how trees respond to drought. Additionally, the results suggest the potential for new disturbances to emerge in forest gaps due to overstory vegetation mortality induced by global warming. These findings contribute to a deeper understanding of increasing drought stress, aid in identifying climate refugia, and inform conservation priorities based on habitat characteristics.
The correlation between climate change and pine tree dieback must be understood to implement a proactive forest management system. In this study, an ensemble model combining random forest, the generalized boosting model, and the generalized linear model was used to analyze the topographical and environmental characteristics of pine trees suffering from dieback in the Wangpicheon Ecosystem and Landscape Conservation Area, and the areas in which pine trees are at risk of dieback were evaluated to promote efficient pine forest management. The results showed that pine trees suffering from dieback in the conservation area were mainly located on ridges, were age class 6 or older, or were in areas with a low topographic wetness index south of the conservation area. An evaluation of the risk of dieback among pine trees was performed based on the results of two ensemble models. An area of 365 ha accounting for 6.8% of the total area was identified as requiring “caution” with respect to the risk of dieback of coniferous forests and mixed forests. The developed methodology is expected to provide valuable information for the implementation of an appropriate management system for the protection of pine and mixed forests from the negative effects of climate change.