Dipteronia sinensis is an endangered relict tree species in the endemic north temperate flora of China, which has important reference values for studying paleoclimate and species variation as well as geographic zonation changes. Based on 96 occurrence points of D. sinensis and 9 environmental factors, the potential geographic distribution of D. sinensis in China under climate change was predicted using MaxEnt model and ArcGIS software, the Jackknife test was used to assess the important factors governing its potential geographic distribution. In addition, response curves were selected to determine the suitable values of environmental factors and further quantitatively predicted the potential geographic distribution of D. sinensis under the climate changet. The results showed that: (1) the prediction accuracy of the MaxEnt model was extremely high, with an area under receiver operating characteristic curve (AUC training value) of 0.959. The potential suitable habitat area of D. sinensis under current climate condition was 103.9 × 104 km2, mainly located in the central and northwestern regions of China; (2) the main environmental factors affecting the potential geographic distribution of D. sinensis were the temperature factor (min temperature of coldest month) and the precipitation factor (annual precipitation); (3) the area of low, high and total suitable habitats showed a decreasing trend under SSP1-2.6 and SSP5-8.5 scenarios in 2070s, and the area of moderately suitable habitats showed an increasing trend under the three scenarios in 2050s and 2070s, and the center of gravity of the potential suitable habitats of D. sinensis would shift to the northwest. Our results can provide a theoretical basis for the scientific management and resource conservation of D. sinensis.

Changes in future climate will have a great impact on biodiversity. Magnolia wilsonii, an endangered tree native to China, has important scientific and medicinal value occurring in western Sichuan, northern Yunnan and western Guizhou. And it has severely declined and become critically endangered in the last years due to habitat loss and fragmentation. In this study, we modeled the current and future distributions of M. wilsonii under three representative concentration pathways (SSP1-2.6, SSP2-4.5 and SSP5-8.5). The results showed that the AUC values of all simulations were greater than 0.940. The key environmental variables affecting the potential distribution of M. wilsonii were the annual precipitation (573-1671 mm), the min temperature of coldest month (10.1ºC-16.2ºC), the coefficient of variation in precipitation seasonality (11.5-160.9), and the standard deviation of temperature seasonality (404.7- 1765.6). The area of the highly suitable habitat was 29.66×104 km², mainly concentrated in Yunnan, Sichuan, Guizhou and Guangxi. Yunnan had the largest suitable habitat, occupying 13.23×104 km², accounting for 44.6% of the highly suitable area. Under the three climate change scenarios, the areas of the suitable habitat of M. wilsonii showed increasing trends, the geometric center of the highly suitable habitat would move to the northeast. Our results can provide a scientific basis for the protection, cultivation, management and sustainable use of M. wilsonii.

This study attempts to discuss the relationship between land use spatial distribution structure and energy‐related carbon emission intensity in Guangdong during 1996–2008. We quantized the spatial distribution structure of five land use types including agricultural land, industrial land, residential and commercial land, traffic land, and other land through applying spatial Lorenz curve and Gini coefficient. Then the corresponding energy‐related carbon emissions in each type of land were calculated in the study period. Through building the reasonable regression models, we found that the concentration degree of industrial land is negatively correlated with carbon emission intensity in the long term, whereas the concentration degree is positively correlated with carbon emission intensity in agricultural land, residential and commercial land, traffic land, and other land. The results also indicate that land use spatial distribution structure affects carbon emission intensity more intensively than energy efficiency and production efficiency do. These conclusions provide valuable reference to develop comprehensive policies for energy conservation and carbon emission reduction in a new perspective.

As an important woody oilseed species in China, Triadica sebifera is not only concerned with the substitution of traditional energy sources, but also plays a considerable role in coping with energy shortages. Accurately predicting the potential geographic distribution of Triadica sebifera in China and understanding its ecological needs are crucial for alleviating the energy crisis and effectively implementing energy substitution strategies. In this study, the potential geographic distribution of Triadica sebifera in China at contemporary and future periods was predicted based on the distribution data of Triadica sebifera in China and the environmental factor variables by Maxent model and ArcGIS software. The combination of important factors governing the potential geographic distribution of Triadica sebifera was assessed by the contribution of environmental factor variables. The accuracy of Maxent model's predictions was assessed by AUC values, TSS values and Kappa statistics. The results show that: High AUC and TSS values indicate high accuracy and performance of the model. The crucial environmental factors limiting the potential geographic distribution of Triadica sebifera are the temperature factor (mean air temperature of the driest quarter), precipitation factor (precipitation of the coldest quarter, precipitation of the wettest month), and the intensity of human activities (hf). The total suitable area for Triadica sebifera is 233.64 × 10⁴ km², primarily located in Yunnan, Sichuan, Hubei, Guizhou, Jiangxi, Guangdong province and Guangxi Zhuang Autonomous Region; its high suitability area is 30.89 × 10⁴ km², accounting for 13.22% of the total suitable area, mainly distributed in Jiangxi, Sichuan and Hunan provinces in the shape of a cake. Under the four typical greenhouse gas emission concentration patterns in the 2050s and 2070s, the areas of high and medium suitable areas for Triadica sebifera will increase, while the area of its low suitable area will decrease. However, the total suitable area will remain relatively unchanged. Its potential suitable habitats show a trend of shifting towards lower latitudes and southeast regions. The study predicted the pattern of Triadica sebifera under different climate change conditions, which can provide guidance for future cultivation of Triadica sebifera as well as for biofuel development and utilization.

Setaria italica (S. italica, Linnaeus, 1753) is a drought-resistant, barren-tolerant, and widely adapted C-4 crop that plays a vital role in maintaining agricultural and economic stability in arid and barren regions of the world. However, the potential habitat of S. italica under current and future climate scenarios remains to be explored. Predicting the potential global geographic distribution of S. italica and clarifying its ecological requirements can help promote sustainable agriculture, which is crucial for addressing the global food crisis. In this study, we predicted the potential global geographic distribution of S. italica based on 3,154 global distribution records using the Maxent model and ArcGIS software. We assessed the constraints on its potential distribution based on the contribution of environmental factors variables. The predictive accuracy of the Maxent model was evaluated using AUC values, TSS values, and Kappa statistics, respectively. The results showed that the Maxent model had a high prediction accuracy, and the simulation results were also reliable; the total suitable habitats of S. italica is 5.54×10⁷ km², which mainly included the United States (North America), Brazil (South America), Australia (Oceania), China, India (Asia), and the Russian Federation (Europe). The most suitable habitat of S. italica was 0.52×10⁷ km², accounting for 9.44% of the total areas, mainly in the United States, India, the Russian Federation, and China. Soil and precipitation (driest monthly precipitation, hottest seasonal precipitation) are the most critical factors limiting the potential distribution of S. italica. Compared with the modern potential distribution, we predict that the four future climate change scenarios will result in varying reductions in the possible geographic ranges of S. italica. Overall, climate change may significantly affect the global distribution of S. italica, altering its worldwide production and trade patterns.

Paeonia rockii has been a traditional medicinal material from time immemorial. It is an important plant resource of ethnic medicine and chinese herbal medicine. It has unique effects on heat and cool blood, promoting blood circulation and dispersing blood stasis, analgesia and promoting menstruational flow. It is also a first-class protected plant. With the increasing demand for the bark and roots of P. rockii in China’s medicinal market, the continuous high-intensity and disorderly excavation has led to a sharp decline in wild resources. P. rockii is in imminent danger and needs to be saved and protected urgently. In this study, the distribution records of P. rockii in China, combined with environmental factors, are used to simulate the current potential distribution area of P. rockii through MaxEnt model. The environmental factors affecting the distribution of P. rockii are obtained by using the contribution rate of environmental factors and a jackknife test analysis, and the appropriate value of environmental factors is determined by using the response curve. The results show that the AUC value of test set data is 0.985 and that of training set data is 0.987. The prediction accuracy of the Maxent model is extremely high and the simulation effect is very good. At present, the high suitable areas of P. rockii are mainly distributed in the shape of cake in Southern Ningxia, southern Gansu and southern Shanxi, accounting for 15.58% of the total suitable areas. The most important environmental factor affecting the geographical distribution of P. rockii is the altitude; Under the future climate change scenario, the total suitable area of P. rockii shows a decreasing trend, among which the area of high suitable area shows an obvious decreasing trend, the mass center of high suitable area of P. rockii generally tends to migrate to the northwest, and the migration range is large under the scenario of high concentration emission. The research results can provide scientific data support for P. rockii to to cope with the changes in suitable areas caused by climate change and the establishment of effective protection, clarify the change and heterogeneity of P. rockii in different regions of China in the future, and clarify its ecological needs, which has certain practical significance.