Vulnerability of subalpine fir species to climate change: using species distribution modeling to assess the future efficiency of current protected areas in the Korean Peninsula

Climate-induced distribution dynamics and niche adaptation of South Korean endemic plants across the Korean Peninsula

As climate change intensifies, endemic plants native to South Korea, especially those in specialized ecological niches, confront heightened risks of distribution shifts and habitat degradation. To provide a comprehensive understanding of these impacts, this study evaluates the climate-induced distribution dynamics and niche adaptation of these endemic species across the entire Korean Peninsula. Utilizing species distribution models (SDMs) for 179 plant species and incorporating environmental variables under projected future climate scenarios, our analysis identified unique distribution and niche adaptation patterns. Findings demonstrate that specialized endemic species are likely to migrate to higher altitudes and latitudes, highlighting their distinct vulnerability due to limited ecological niches. Our comparative approach underscores the necessity for refined conservation strategies that address the specific requirements of these endemic species, as opposed to those with wider distributions. This research offers valuable insights into biodiversity conservation amid climate change, proposing targeted actions such as the establishment of protected areas, habitat restoration, and the implementation of assisted migration strategies to safeguard these vital endemic plant species throughout the Korean Peninsula.

Local adaptation of Pinus leiophylla under climate and land use change models in the Avocado Belt of Michoacán

Climate change and land use change are two main drivers of global biodiversity decline, decreasing the genetic diversity that populations harbour and altering patterns of local adaptation. Landscape genomics allows measuring the effect of these anthropogenic disturbances on the adaptation of populations. However, both factors have rarely been considered simultaneously. Based on a set of 3660 SNPs from which 130 were identified as outliers by a genome-environment association analysis (LFMM), we modelled the spatial turnover of allele frequencies in 19 localities of Pinus leiophylla across the Avocado Belt in Michoacán state, Mexico. Then, we evaluated the effect of climate change and land use change scenarios, in addition to evaluating assisted gene flow strategies and connectivity metrics across the landscape to identify priority conservation areas for the species. We found that localities in the centre-east of the Avocado Belt would be more vulnerable to climate change, while localities in the western area are more threatened by land conversion to avocado orchards. Assisted gene flow actions could aid in mitigating both threats. Connectivity patterns among forest patches will also be modified by future habitat loss, with central and eastern parts of the Avocado Belt maintaining the highest connectivity. These results suggest that areas with the highest priority for conservation are in the eastern part of the Avocado Belt, including the Monarch Butterfly Biosphere Reserve. This work is useful as a framework that incorporates distinct layers of information to provide a more robust representation of the response of tree populations to anthropogenic disturbances.

Spatial genetic structure and seed quality of a southernmost Abies nephrolepis population

Abies nephrolepis (Trautv. ex Maxim.) Maxim. has its southernmost populations in South Korea and they are expected to decline under climate change. To establish a strategic conservation plan, this study aimed to investigate the spatial genetic structure and seed characteristics of A. nephrolepis. We used nine microsatellite markers on 165 individuals of A. nephrolepis and sampled seeds in a southernmost population at Mt. Hambaeksan, South Korea. We observed a high level of heterozygosity, and a simulation study found that sampling 20 individuals was enough to secure sufficient genetic diversity on average. Spatial autocorrelation analysis revealed that individuals had a positive genetic relationship until 30 m. Bayesian clustering models, STRUCTURE and GENELAND, failed to achieve a consensus in the optimal number of population (K), estimating K = 1 and K = 2, respectively. Principal coordinate analysis supported the absence of genetic substructure within the study population. There was a large variance in seed production among mother trees. On average, seeds of A. nephrolepis from Mt. Hambaeksan had a purity of 70.4% and a germination percentage of 32.2%. We found that seed weight was the most effective indicator of seed quality. Mother trees at higher altitudes had poorer purity which is threatening to A. nephrolepis considering the upslope retreat of subalpine species under climate change. Our results provide insights into the interactions among spatial processes, genetic structure, and seed quality within a population of A. nephrolepis.

Tropical Cyclone Disturbances Induce Contrasting Impacts on Forest Structure, Plant Composition, and Soil Properties in Temperate Broadleaf and Coniferous Forests

Knowledge of forest recovery processes after severe disturbances, such as tropical cyclones, is essential for understanding the mechanisms maintaining forest diversity and ecosystem functioning. However, studies examining the impact of tropical cyclones on forest dynamics are still rare, especially in Northeast Asia. Here, we explore the complex responses of vegetation and soil chemistry to severe tropical cyclone disturbances in Hallasan National Park in South Korea. Vegetation and soil were examined five years before and five years after passages of tropical cyclones in 2012 in natural broadleaf and coniferous forests along an elevation gradient from 950 to 1770 m a.s.l., including the largest population of endemic Abies koreana. Tropical cyclones caused abundant tree mortality, resulting in a 46% decrease in stem basal area. Tropical cyclone disturbances triggered the spread of pioneer trees and shrubs and intense clonal propagation of graminoids, including dwarf bamboo, resulting in less diverse understory vegetation, especially in coniferous forests. In contrast, broadleaf forests at lower elevations experienced only minor disturbance. Opening of canopies after tropical cyclone disturbance led to the decrease in soil cations and doubling of available soil phosphorus stock, which likely contributed to the increased coverage of clonal graminoids, especially in coniferous forests (from 36 to 66%). Hence, increased competition of graminoids and reduction in seed fall and seedling recruitment prevented A. koreana regeneration. The subalpine forest dominated by A. koreana is forecasted to gradual loss due to the fact of temperature increases, intensified tropical cyclones and, particularly, due to the altered competition between dwarf bamboo and fir seedlings.

Environmental differences explain subtle yet detectable genetic structure in a widespread pollinator

BACKGROUND

The environment is a strong driver of genetic structure in many natural populations, yet often neglected in population genetic studies. This may be a particular problem in vagile species, where subtle structure cannot be explained by limitations to dispersal. Consequently, these species might falsely be considered quasi-panmictic and hence potentially mismanaged. A species this might apply to, is the buff-tailed bumble bee (Bombus terrestris), an economically important and widespread pollinator, which is considered to be quasi-panmictic at mainland continental scales. Here we aimed to (i) quantify genetic structure in 21+ populations of the buff-tailed bumble bee, sampled throughout two Eastern European countries, and (ii) analyse the degree to which structure is explained by environmental differences, habitat permeability and geographic distance. Using 12 microsatellite loci, we characterised populations of this species with Fst analyses, complemented by discriminant analysis of principal components and Bayesian clustering approaches. We then applied generalized dissimilarity modelling to simultaneously assess the informativeness of geographic distance, habitat permeability and environmental differences among populations in explaining divergence.

RESULTS

Genetic structure of the buff-tailed bumble bee quantified by means of Fst was subtle and not detected by Bayesian clustering. Discriminant analysis of principal components suggested insignificant but still noticeable structure that slightly exceeded estimates obtained through Fst analyses. As expected, geographic distance and habitat permeability were not informative in explaining the spatial pattern of genetic divergence. Yet, environmental variables related to temperature, vegetation and topography were highly informative, explaining between 33 and 39% of the genetic variation observed.

CONCLUSIONS

In contrast to previous studies reporting quasi-panmixia in continental populations of this species, we demonstrated the presence of subtle population structure related to environmental heterogeneity. Environmental data proved to be highly useful in unravelling the drivers of genetic structure in this vagile and opportunistic species. We highlight the potential of including these data to obtain a better understanding of population structure and the processes driving it in species considered to be quasi-panmictic.

Non-Pessimistic Predictions of the Distributions and Suitability of Metasequoia glyptostroboides under Climate Change Using a Random Forest Model

Metasequoia glyptostroboides Hu & W. C. Cheng, which is a remarkable rare relict plant, has gradually been reduced to its current narrow range due to climate change. Understanding the comprehensive distribution of M. glyptostroboides under climate change on a large spatio-temporal scale is of great significance for determining its forest adaptation. In this study, based on 394 occurrence data and 10 bioclimatic variables, the global potential distribution of M. glyptostroboides under eight different climate scenarios (i.e., the past three, the current one, and the next four) from the Quaternary glacial to the future was simulated by a random forest model built with the biomod2 package. The key bioclimatic variables affecting the distribution of M. glyptostroboides are BIO2 (mean diurnal range), BIO1 (annual mean temperature), BIO9 (mean temperature of driest quarter), BIO6 (min temperature of coldest month), and BIO18 (precipitation of warmest quarter). The result indicates that the temperature affects the potential distribution of M. glyptostroboides more than the precipitation. A visualization of the results revealed that the current relatively suitable habitats of M. glyptostroboides are mainly distributed in East Asia and Western Europe, with a total area of approximately 6.857 × 106 km2. With the intensification of global warming in the future, the potential distribution and the suitability of M. glyptostroboides have a relatively non-pessimistic trend. Whether under the mild (RCP4.5) and higher (RCP8.5) emission scenarios, the total area of suitable habitats will be wider than it is now by the 2070s, and the habitat suitability will increase to varying degrees within a wide spatial range. After speculating on the potential distribution of M. glyptostroboides in the past, the glacial refugia of M. glyptostroboides were inferred, and projections regarding the future conditions of these places are expected to be optimistic. In order to better protect the species, the locations of its priority protected areas and key protected areas, mainly in Western Europe and East Asia, were further identified. Our results will provide theoretical reference for the long-term management of M. glyptostroboides, and can be used as background information for the restoration of other endangered species in the future.