Effects of Land-Use Change on the Pollination Services for Litchi and Longan Orchards: A Case Study of Huizhou, China

Land-use change has a significant impact on the structure and function of ecosystems and is an important reason for the imbalance between the supply and demand of ecosystem services. Pollination services are indispensable functions of ecosystems. In recent years, land-use change has caused a decline in the abundance of pollinators, thereby affecting the supply of pollination services, which has been a major concern for governments and scholars. Currently, there is an insufficient exploration of the impact mechanism of land-use change on pollination services. The application of a pollination service evaluation model based on land-use data uses a large amount of empirical data, which greatly affects the accuracy of regional evaluation results. This study uses Huizhou as a representative example. Remote sensing images from 2015 and 2019 were used to interpret the land-use data of the region, and the spatiotemporal changes in the land use were then analyzed. Due to their high pollination dependence, litchi and longan were selected as the research objects. Basic data such as the main pollinator species of litchi and longan and floral plant species were obtained through field sampling surveys. The InVEST model was used to evaluate the abundance of pollinators in litchi and longan orchards, and the abundance of pollinators was used to represent the value of pollination services in litchi and longan orchards. Then, the Hotspot analysis method was used to analyze the change in the spatial pattern of the pollinator abundance in litchi and longan orchards. The main influencing factors of pollination service in litchi and longan orchards were analyzed by a Geographical detector. Finally, we have explored the impact mechanism of land-use change on pollination services. The following are the results of this research. The pollinator abundance in the orchards of litchi and longan and their buffer zones in Huizhou decreased by 6.64% and 13.94% from 2015 to 2019, respectively. The wild bee abundance in forest land and rainfed cropland decreased by varying degrees. The spatial aggregation characteristics of pollinator abundance in litchi and longan orchards demonstrated an increase in cold spots, whereas the hot spots decreased and were more dispersed. In the study area, the area change and land-use change of natural or semi-natural habitats, such as forest land, rainfed cropland, and grassland, affected the pollination services for litchi and longan orchards. Within the types of changing land-use, the change of forest land has the greatest impact on litchi and longan pollination services. The impact degrees of Forest land area, rainfed cropland area, area under litchi and longan orchards, and forest landscape fragmentation on the pollination services for litchi and longan orchards were 0.20, 0.16, 0.21, and 0.26, respectively.