Predicting Suitable Environments and Potential Occurrences for Cinnamomum camphora (Linn.) Presl

Contrasting range changes and drivers of four forest foundation species under future climate change in China

Forest foundation species, vital for shaping community structure and dynamics through non-trophic level interactions, are key to forest succession and sustainability. Despite their ecological importance, the habitat ranges of these species in China and their responses to future climate change remain unclear. Our study employed the optimal MaxEnt model to assess the range shifts and their essential drivers of four typical forest foundation species from three climatic zones in China under climate scenarios, including Acer tegmentosum, Acer pseudo-sieboldianum (temperate zone), Quercus glandulifera (subtropical zone), and Ficus hispida (tropical zone). The optimal MaxEnt model exhibited high evaluation indices (AUC values > 0.90) for the four foundation species, indicating excellent predictive performance. Currently, we observed that A. tegmentosum and A. pseudo-sieboldianum are predominantly inhabited temperate forest areas in northeastern China, Q. glandulifera is primarily concentrated in subtropical forests in southeastern China, and F. hispida is mainly distributed across the tropical forests in southern China. Climate factors, particularly temperature, emerged as the primary environmental factors influencing the potential range of forest foundation species. Moreover, precipitation strongly influenced the potential range of A. tegmentosum and A. pseudo-sieboldianum, while elevation exhibited a greater impact on the range of Q. glandulifera and F. hispida. Under future climate scenarios, suitable areas for A. tegmentosum and A. pseudo-sieboldianum tend to expand southward, F. hispida tends to expand northward, while Q. glandulifera exhibited a tendency to contract towards the center. This study advances our understanding of the spatial and temporal dynamics of forest foundation species in China under climate change, providing critical insights for conservation efforts and sustainable forest management practices.

Predictive ecological niche model for Cinnamomumparthenoxylon (Jack) Meisn. (Lauraceae) from Last Glacial Maximum to future in Vietnam

Cinnamomumparthenoxylon (Jack) Meisn. is a tree in genus Cinnamomum that has been facing global threats due to forest degradation and habitat fragmentation. Many recent studies aim to describe habitats and assess population and species genetic diversity for species conservation by expanding afforestation models for this species. Understanding their current and future potential distribution plays a major role in guiding conservation efforts. Using five modern machine-learning algorithms available on Google Earth Engine helped us evaluate suitable habitats for the species. The results revealed that Random Forest (RF) had the highest accuracy for model comparison, outperforming Support Vector Machine (SVM), Classification and Regression Trees (CART), Gradient Boosting Decision Tree (GBDT) and Maximum Entropy (MaxEnt). The results also showed that the extremely suitable ecological areas for the species are mostly distributed in northern Vietnam, followed by the North Central Coast and the Central Highlands. Elevation, Temperature Annual Range and Mean Diurnal Range were the three most important parameters affecting the potential distribution of C.parthenoxylon. Evaluation of the impact of climate on its distribution under different climate scenarios in the past (Last Glacial Maximum and Mid-Holocene), in the present (Worldclim) and in the future (using four climate change scenarios: ACCESS, MIROC6, EC-Earth3-Veg and MRI-ESM2-0) revealed that of C.parthenoxylon would likely expand to the northeast, while a large area of central Vietnam will gradually lose its adaptive capacity by 2100.

Genome and whole-genome resequencing of Cinnamomum camphora elucidate its dominance in subtropical urban landscapes

BACKGROUND

Lauraceae is well known for its significant phylogenetic position as well as important economic and ornamental value; however, most evergreen species in Lauraceae are restricted to tropical regions. In contrast, camphor tree (Cinnamomum camphora) is the most dominant evergreen broadleaved tree in subtropical urban landscapes.

RESULTS

Here, we present a high-quality reference genome of C. camphora and conduct comparative genomics between C. camphora and C. kanehirae. Our findings demonstrated the significance of key genes in circadian rhythms and phenylpropanoid metabolism in enhancing cold response, and terpene synthases (TPSs) improved defence response with tandem duplication and gene cluster formation in C. camphora. Additionally, the first comprehensive catalogue of C. camphora based on whole-genome resequencing of 75 accessions was constructed, which confirmed the crucial roles of the above pathways and revealed candidate genes under selection in more popular C. camphora, and indicated that enhancing environmental adaptation is the primary force driving C. camphora breeding and dominance.

CONCLUSIONS

These results decipher the dominance of C. camphora in subtropical urban landscapes and provide abundant genomic resources for enlarging the application scopes of evergreen broadleaved trees.

Variation in Community Structure of the Root-Associated Fungi of Cinnamomum camphora Forest

Plant-associated microbial communities play essential roles in the vegetative cycle, growth, and development of plants. Cinnamomum camphora is an evergreen tree species of the Lauraceae family with high ornamental, medicinal, and economic values. The present study analyzed the composition, diversity, and functions of the fungal communities in the bulk soil, rhizosphere, and root endosphere of C. camphora at different slope positions by high-throughput sequencing. The results showed that the alpha diversity of the fungal communities in the bulk soil and rhizosphere of the downhill plots was relatively higher than those uphill. A further analysis revealed that Mucoromycota, the dominant fungus at the phylum level, was positively correlated with soil bulk density, total soil porosity, mass water content, alkaline-hydrolyzable nitrogen, maximum field capacity, and least field capacity. Meanwhile, the prevalent fungus at the class level, Mortierellomycetes, was positively correlated with total phosphorus and available and total potassium, but negatively with alkaline-hydrolyzable nitrogen. Finally, the assignment of the functional guilds to the fungal operational taxonomic units (OTUs) revealed that the OTUs highly enriched in the downhill samples compared with the uphill samples, which were saprotrophs. Thus, this study is the first to report differences in the fungal community among the different soil/root samples and between C. camphora forests grown at different slope positions. We also identified the factors favoring the root-associated beneficial fungi in these forests, providing theoretical guidance for managing C. camphora forests.

Distributional Response of the Rare and Endangered Tree Species Abies chensiensis to Climate Change in East Asia

Globally, increasing temperatures due to climate change have severely affected natural ecosystems in several regions of the world; however, the impact on the alpine plant may be particularly profound, further raising the risk of extinction for rare and endangered alpine plants. To identify how alpine species have responded to past climate change and to predict the potential geographic distribution of species under future climate change, we investigated the distribution records of A. chensiensis, an endangered alpine plant in the Qinling Mountains listed in the Red List. In this study, the optimized MaxEnt model was used to analyse the key environmental variables related to the distribution of A. chensiensis based on 93 wild distribution records and six environmental variables. The potential distribution areas of A. chensiensis in the last interglacial (LIG), the last glacial maximum (LGM), the current period, and the 2050s and 2070s were simulated. Our results showed that temperature is critical to the distribution of A. chensiensis, with the mean temperature of the coldest quarter being the most important climatic factor affecting the distribution of this species. In addition, ecological niche modeling analysis showed that the A. chensiensis distribution area in the last interglacial experiencing population expansion and, during the last glacial maximum occurring, a population contraction. Under the emission scenarios in the 2050s and 2070s, the suitable distribution area would contract significantly, and the migration routes of the centroids tended to migrate toward the southern high-altitude mountains, suggesting a strong response from the A. chensiensis distribution to climate change. Collectively, the results of this study provide a comprehensive and multidimensional perspective on the geographic distribution pattern and history of population dynamics for the endemic, rare, and endangered species, A. chensiensis, and it underscores the significant impact of geological and climatic changes on the geographic pattern of alpine species populations.

Climate Change Reveals Contractions and Expansions in the Distribution of Suitable Habitats for the Neglected Crop Wild Relatives of the Genus Vigna (Savi) in Benin

Sustainable conservation of crop wild relatives is one of the pathways to securing global food security amid climate change threats to biodiversity. However, their conservation is partly limited by spatio-temporal distribution knowledge gaps mostly because they are not morphologically charismatic species to attract conservation attention. Therefore, to contribute to the conservation planning of crop wild relatives, this study assessed the present-day distribution and predicted the potential effect of climate change on the distribution of 15 Vigna crop wild relative taxa in Benin under two future climate change scenarios (RCP 4.5 and RCP 8.5) at the 2055-time horizon. MaxEnt model, species occurrence records, and a combination of climate- and soil-related variables were used. The model performed well (AUC, mean = 0.957; TSS, mean = 0.774). The model showed that (i) precipitation of the driest quarter and isothermality were the dominant environmental variables influencing the distribution of the 15 wild Vigna species in Benin; (ii) about half of the total land area of Benin was potentially a suitable habitat of the studied species under the present climate; (iii) nearly one-third of the species may shift their potentially suitable habitat ranges northwards and about half of the species may lose their suitable habitats by 5 to 40% by 2055 due to climate change; and (iv) the existing protected area network in Benin was ineffective in conserving wild Vigna under the current or future climatic conditions, as it covered only about 10% of the total potentially suitable habitat of the studied species. The study concludes that climate change will have both negative and positive effects on the habitat suitability distribution of Vigna crop wild relatives in Benin such that the use of the existing protected areas alone may not be the only best option to conserve the wild Vigna diversity. Integrating multiple in situ and ex situ conservation approaches taking into account “other effective area-based conservation measures” is recommended. This study provides a crucial step towards the development of sustainable conservation strategies for Vigna crop wild relatives in Benin and West Africa.

High-Throughput Sequencing Analysis of the Composition and Diversity of the Bacterial Community in Cinnamomum camphora Soil

Soil bacterial communities and root-associated microbiomes play important roles in the nutrient absorption and healthy growth of host plants. Cinnamomum camphora is an important timber and special economic forest tree species in Fujian Province. In this study, the high-throughput sequencing technique was used to analyze the composition, diversity, and function of the bacterial communities present in the soil from different samples and slope positions of C. camphora. The results of this analysis demonstrated that the related bacterial communities in C. camphora soil were mainly clustered based on sample type. Bacterial alpha diversity in the rhizosphere and bulk soil of C. camphora growing downhill was higher than that of C. camphora growing uphill. At the phylum level, Bacteroidetes, Proteobacteria, Chloroflexi, and Gemmatimonadetes were positively correlated with pH, available phosphorus, total phosphorus, available potassium, and total potassium, while Acidobacteria and Verrucomicrobia were negatively correlated with alkaline-hydrolyzable nitrogen. These results show that there were remarkable differences in the composition, diversity, and function of related bacterial communities between different sample types of C. camphora soil. The slope position had a marked effect on the bacterial communities in the rhizosphere and bulk soil, while the root endosphere remained unaffected.