- Author: LIU Chao, DONG Xingguang, TIAN Luming, HUO Hongliang, XU Jiayu, QI Dan, ZHANG Ying, ZHANG Simeng, YANG Xiang, GUO Rui, NIE Hanyu, CAO Yufen
- Keywords: Pyrus pashia; Maxent model; Climate change
- DOI: 10.13925/j.cnki.gsxb.20210323
- Received date:
- Accepted date:
- Online date:
PDF （） Abstract（）
Abstract:【Objective】This study aimed to predict the distribution of Pyrus pashia in the last glacial maximum period, the mid-holocene period, the modern period and in the future (in the year of 2070)based on the Maxent model, and to calculate the suitable habitat areas under different climate condi-tions, combined with geographic information system (GIS) for visual expression.【Methods】The exten-sive retrieval of detailed distribution records of P. pashia in China was conducted via the Global Biodi-versity Information Platform (GBIF, https://www.gbif.org/), the China Digital Plant Herbarium (CVH,http://v5.cvh.org.cn/) and other relevant online databases, to obtain the distribution data of P. pashia inChina. 6 climate and environmental data were obtained by accessing the World Climate Database (http://www.worldclim.org/), and the distribution points of P. pashia data and environmental variable datawere imported into MaxEnt software separately and visualized with geographic information system(GIS) to predict the distribution of P. pashia under different climate conditions.【Results】The high suit-able areas of P. pashia during last glacial maximum were mainly distributed in Yunnan, Eastern Tibet,Southern and Eastern Sichuan, Western Guizhou and Western Guangxi. The total suitable area was963 100 km2, the high, medium and low suitable habitats was 482 800 km2, 220 100 km2 and 260 300 km2,respectively. From the last glacial maximum to the mid-holocene, the suitability area sharply decreased.Compared with the last glacial maximum, the high-suitable area in the Southern Yunnan became medi-um-suitable area, the high suitable area in the Eastern Sichuan disappeared, and the high suitable area in Guizhou and Guangxi also decreased or even disappeared. The total suitable area was 590 200 km2, the high, medium and low suitable habitats were 291 700 km2, 163 900 km2 and 145 500 km2, respectively.From the mid-Holocene to nowadays, the suitability areas gradually increased. Compared with the mid-Holocene, the high suitable area was mainly concentrated in the Nnorthern Yunnan, Southern Sichuan,Western Guizhou and Eastern Tibet. The total area of the suitable habitats was 740 300 km2, the high,medium and low suitable habitats were 351 300 km2, 191 200 km2 and 197 800 km2 respectively. From the now to the future, the suitable area would gradually increase. Compare with nowt, the high suitable areas were mainly concentrated in the Northern Yunnan, Southern Sichuan, Western Guizhou and East- ern Tibet. The total area of suitable habitats was 829 900 km2, and the high, medium and low suitablehabitats were 351 300 km2, 212 200 km2, 271 000 km2, respectively. The Jackknife method was used to screen out the main environmental factors affecting the distribution of P. pashia from the 6 bioclimatic indicators. Among them, temperature seasonality (Bio4) had the largest contribution rate, reaching 46.3%, indicating that the temperature seasonality would play a leading role in the potential geographi-cal distribution pattern of P. pashia. The precipitation of warmest quarter (Bio18) contribution rate was 24.8%, Isothermality (Bio3) contribution rate was 16.3%, and mean temperature of warmest quarter (Bio10) contribution rate was 10%, indicating that these three environmental factors might also play acertain role in the geographical distribution pattern of P. pashia. According to the response curve of the dominant environmental variables, when the probability of existence was over 0.5, the corresponding ecological factor value would be more suitable for the growth of P. pashia. The temperature seasonality suitable for the survival of P. pashia was 4000-5200, and the precipitation of warmest quarter was 550-1000 mm, the Isothermality was ＞42%, and the mean temperature of warmest quarter was 11-23 ℃.【Conclusion】The temperature seasonality would be the dominant climatic factor affecting the distribu-tion of P. pashia. In addition, the precipitation of warmest quarter, isothermality and annual precipita-tion might also play an important role in the distribution of P. pashia. Compared with water, tempera-ture would have a greater impact on population distribution. In this study, the total distribution area of P. pashia during the last glacial maximum increased by 30.09%, and the distribution center was 0.14°lower in latitude than that in modern time, indicating that P. pashia might be not directly affected by gla-ciers during the last glacial maximum. This might have a high degree of topographic heterogeneity with the Sichuan Liangshan, Yunnan-Guizhou Plateau and other regions where P. pashia was located. With small changes in humidity, the subtropical zone in the Suthern China is located in the junction of the subtropical and tropical regions, which might be due to airflow movement, precipitation, the water and heat conditions on the mountain surface suitable for the growth of forest vegetation. Therefore, P. pa-shia could be preserved in situ under the complex mountain terrain and mild microenvironment, with noadverse affection by the ice age or restrictive effect.