Effects Of Wind Farm And Its Sounding Landscape Factors On Magpie (Pica Pica) Nest In Agroforestry System ——A Case Study Of Chongming Beihu Wind Farm

In recent decades,the development of wind energy has played a key role in reducing carbon emissions to meet the growing need to mitigate climate change.Although wind energy is generally regarded as an environmentally friendly alternative energy,the continuous growth of the number of wind farms may have a long-term and complex effects on the community structure and population characteristics of surrounding birds.Reproductive life history is very important for the population maintenance of wild animals.However,there is a lack of research on the changes of reproductive life history of birds around the wind farm and its related mechanisms.In order to find evidence to prove the impact of the wind farm on birds and the mechanism behind these effects,this study selects magpie and magpie nest,the dominant species of local resident birds as the research object,in combination with the agroforestry ecosystem where the local wind farm is located,data collection combined with routine investigation and unmanned aerial vehicle assistance.From March 2018 to June 2021,we selected quadrats inside the wind farm(within 1000 m of the closest wind turbine)and quadrats outside the wind farm(over 1000 m from the closest wind turbine)on Chongming Island,Shanghai,and recorded the magpie density,nest density,nest characteristics of magpie,the magpie breeding condition(participating in breeding or not participating in breeding),and out of nest rate(number of young birds out of each nest).At the same time,the landscape variables that may be related to magpie reproductive ecology in the study quadrats were interpreted and analyzed.Through the analysis,the main results shows that:1.From March 2018 to June 2019,323 magpies were found in the quadrats inside and outside wind farms.The results showed that :(1)The density of magpie outside the wind farm was significantly higher than that inside the wind farm;(2)There was a significant positive correlation between the magpie density in the 500 m buffer and the distance to the nearest wind turbine;(3)The density of magpies in the quadrat increased with the average distance between magpies and the nearest wind turbine and the proportion of river and forest in the quadrat increased,but decreased with the proportion of buildings and farmland shelterbelt in the quadrat increased.2.During the breeding season from March 2018 to June 2021,a total of 461 magpie nests in the natural sites were found in the quadrats inside and outside wind farms.The results showed that :(1)The total nest density and breeding nest density of the quadrat outside the wind farm were significantly higher than that of the quadrat inside the wind farm;(2)The average results of landscape variables in the quadrat showed that the total nest density increased with the increase of the distance from the center of the quadrat to the nearest wind turbine and the proportion of river and ditches in the quadrat,but decreased with the increase of the proportion of forest and farmland in the quadrat;(3)The impact of landscape factors on new nest density was basically the same as that on total nest density.In addition,the new nest density also increased with the increase of the proportion of farmland forest network in the quadrat;(4)Different from the total nest density and the new nest density,the breeding nest density only increased with the increase of the proportion of farmland shelterbelt in the quadrat.3.In the breeding season from March 2018 to June 2021 and November to December of the same year,nest characteristic factors of 461 magpie nests in the natural sites were found in the quadrats inside and outside wind farms.The results showed that :(1)The new nest size outside the wind farm was significantly higher than that inside the wind farm;(2)The nest height of total nests,new nests and breeding nests inside the wind farm quadrat were significantly lower than those outside the wind farm quadrat;(3)Although there was no significant difference in the damage rate of nests inside and outside the wind farm,the damage rate of nests inside the wind farm was higher than that outside the wind farm;(4)The relationship between magpie nest characteristics and nest density in the quadrat showed that higher nest height was positively correlated with nest density(total nest density and new nest density).4.In the breeding season from March 2021 to mid-April 2021,a total of 142 participating breeding nests and 56 un-participating breeding nests were found inside the wind farm area.Due to the short and concentrated time of magpie out of nest,in the breeding season from mid-April 2021 to mid-May 2021,the sampling record of 23 participating breeding nests was recorded.The results showed that :(1)The number of participating breeding nests increased with the increase of the buildings proportion within the buffer of 125 m,increasing with the decrease of ditch proportion in 50 m buffer and impervious surface in 25 m buffer,at the same time,surprisingly,the number of participating breeding nests decreased as the distance to the nearest wind turbine increased;(2)The out of nest rate of magpies increased with the proportion of buildings in the 200 m buffer and the proportion of farmland in the 150 m buffer.According to the above results,I believed that the negative effects brought by the wind turbine(presumably air vortex and wind)lead to the decrease of nest height near the wind turbine,and increase the damage rate of nests,and thus the decrease of nest density around the wind turbine.However,the increase of river and farmland shelterbelt network will compensate for the recovery of nest density.Different landscape factors have different impacts on magpie reproduction at different scales,in the process of wind farm construction,we should make reasonable planning to maximize ecological benefits.