Comparative analyses of plastomes in Allaeanthus and Malaisia: structure, evolution, and phylogeny.

The small genera Allaeanthus and Malaisia within the Moraceae have important edible, medicinal, and economic value. However, complete plastome blueprints and a well-resolved evolutionary history of these two genera are still lack, thereby limiting their conservation and application. The recent discovery of a new distribution of Allaeanthus kurzii in Hainan, China, marked by the collection of two unique samples, alongside three samples of Malaisia scandens, has opened new avenues for research. This study aimed to compare the Allaeanthus and Malaisia plastomes of Hainan Province samples with those of samples from other regions, focusing on plastome structure, codon usage bias, natural selection, and the evolutionary history of A. kurzii and M. scandens. The results showed that both species had a quadripartite plastome structure, with sizes ranging from 162,134 to 162,170 bp for A. kurzii and 161,235 to 162,134 bp for M. scandens. Both species displayed loss of the infA gene and reduction of the rpl22 gene. Two highly variable regions (petD-trnD-GUC and rpl20-clpP) and three highly variable genes (rpl20, petB, and rpl16) were identified in A. kurzii, while two highly variable regions (ycf2-ndhB and ccsA-ndhE) and three highly variable genes (psbT, rpl36, and ycf2) were found in M. scandens. The protein-coding sequences (CDSs) of the Allaeanthus and Malaisia plastomes exhibited similar patterns of adaptive indices and codon usage frequencies. The genes associated with photosynthesis underwent strong purifying selection. Phylogenetic analysis revealed that Allaeanthus, Broussonetia, and Malaisia constituted a monophyletic group, with Malaisia being more closely related to Broussonetia. Broussonetia diversified approximately 19.78 million years ago, Malaisia approximately 4.74 million years ago, and Allaeanthus approximately 16.18 million years ago. These new plastome-based discoveries will guide conservation planners and medicinal plant breeders and genetic resource development for these species in the region.

Four New Species of Strobilomyces (Boletaceae, Boletales) from Hainan Island, Tropical China.

Strobilomyces, one of the most noticeable genera of Boletaceae (Boletales), is both ecologically and economically important. Although many studies have focused on Strobilomyces in China, the diversity still remains incompletely understood. In the present study, several collections of Strobilomyces from Hainan Island, tropical China were studied based on morphology and molecular phylogenetic analyses. Four species are described as new, viz. S. baozhengii, S. conicus, S. hainanensis, and S. pachycystidiatus. Detailed descriptions, color photos of fresh basidiomata, and line drawings of microstructures of the four species are presented.

[Spatiotemporal evolution of habitat quality in three basins of Hainan Island based on InVEST model]. / 基于InVEST模型的海南岛三大流域生境质量时空演变.

Based on land use data of five periods during 1980 to 2020, using the InVEST model and the methods of land use transfer, habitat quality change rate and spatial statistical analysis, we explored the changes of habitat quality and its spatial distribution characteristics in the three major basins of Hainan Island (Nandu River, Changhua River and Wanquan River). The results showed that woodlands were the main land use type in the three basins of Hainan Island, accounting for more than 70% of the total area. From 1980 to 2020, the area of construction land increased the most, reaching up to 169.09 km2, mainly from cultivated land and woodland. The spatial distribution pattern of habitat quality in the study area was higher in the upstream and head water areas and lower in the mid and downstream regions. Overall, habitat quality index increased slightly for a short period and then decreased significantly during the study period. Among the three basins, habitat quality of Wanquan River Basin was the highest, followed by Changhua River Basin, and Nandu River Basin was the lowest. The habitat quality of Nandu River Basin fluctuated greatly and was strongly affected by human disturbance. From 1980 to 2020, the change rate of habitat quality in the three basins generally decreased by 0.5%, which was significantly degraded from 2010 to 2020. From 1980 to 2020, the spatial distribution of habitat quality in the study area displayed strong autocorrelation and significant aggregation. The hot spot area of habitat quality was mainly concentrated near the head water and upstream areas of the three basins, while the cold spot area was mainly distributed in the estuary area of the three basins, along with the mid and downstream areas of the Nandu River. These results would provide scientific reference for biodiversity conservation and ecological restoration efforts in the three basins of Hainan Island.

Gross ecosystem product accounting of national park: Taking Hainan Tropical Rainforest National Park as an example.

Hainan Tropical Rainforest National Park has the most representative and largest contiguous tropical rainforest in China, which has advantages in exploring the realization mechanism of ecological product value in national parks. Based on the basic framework of "The Technical Guideline on Gross Ecosystem Product (GEP)", we constructed a GEP accounting system in line with the characteristics of tropical rain forest national park, and calculated the GEP of Hainan Tropical Rainforest National Park in 2019. The results showed that the GEP of Hainan Tropical Rainforest National Park in 2019 was 204.513 billion yuan, and the GEP per unit area was 0.046 billion yuan·km-2. Among all the service types, the value of material services was 4.850 billion yuan, accounting for 2.4% of the total GEP in the national park. The ecosystem regulation service value was 168.891 billion yuan, accounting for 82.6%. The value of cultural services was 30.772 billion yuan, accounting for 15.0%. Among different ecosystem types, the unit area value of the tropical rain forest ecosystem represented by mountain rain forest, lowland rain forest, deciduous monsoon forest, and tropical cloud forest was much higher than that of plantation or other ecosystems, indicating the dominant role of tropical rain forest ecosystem in providing ecosystem services. In addition, based on the GEP accounting results of the national park, we put forward relevant suggestions for further exploring the realization path and realization mechanism of ecological product value.