Data from: Wind farms affect the occurrence, abundance and population trends of small passerine birds: the case of the Dupont's lark

1.The assessment of the effects of wind farms on bird populations is commonly based on collision fatality records. This could undervalue the effect of wind farms on small-sized birds. We evaluate the effect of wind turbines on occurrence, abundance and population trends of a threatened small passerine species, the Dupont's lark Chersophilus duponti. To our knowledge, this is one of the first studies addressing the effect of wind farms on population trends using time series data from multiple wind farms.

2.We estimated population trends by fitting a switching linear trend model with the software TRIM (Trend & Indices for Monitoring data). We used multiannual data surveys of five populations in the presence of wind farms and nine in their absence (2008–2016 period). Furthermore, we fitted a logistic and a negative binomial regression model to test the effect of wind farm proximity on species occurrence and abundance in 2016, respectively. We incorporated local connectivity and habitat availability estimates in both models as predictors.

3.Results showed a negative trend overall, but that was significantly more regressive in the presence of wind farms: 21.0% versus 5.8% average annual decline in the absence of wind farms.

4.Dupont's lark occurrence and abundance in 2016 were negatively affected by measures of population isolation and positively affected by the distance to wind farms.

5.These results highlight the negative effect of isolation and wind farm proximity on Dupont's lark population parameters. Taking into account the metapopulation structure exhibited by the species in the study area, this work established a 4.5 km threshold distance from wind farms, beyond which Dupont's lark populations should be unaffected.

6.Synthesis and applications. This work highlights the negative impact of wind farms on small-sized birds and provides a 4.5 km threshold distance that should be taken into account in the design of future wind energy projects. Moreover, we suggest an analytical approach based on population trends, species abundance and occurrence variation in relation to wind farms, useful for the assessment of wind farm impacts on small-sized birds.

1. 评估风电场对鸟类种群的影响通常以碰撞死亡记录为依据，但该方法可能低估风电场对小型鸟类的影响。本研究针对受胁小型雀形目物种——杜氏百灵（Dupont's lark，Chersophilus duponti），探究风力涡轮机对其出现率、种群丰度及种群动态的影响。据我们所知，本研究是首批利用多风电场时间序列数据，分析风电场对种群动态影响的研究之一。
2. 我们借助TRIM（Trend & Indices for Monitoring data，监测数据趋势与指数）软件，通过拟合转换线性趋势模型估算种群动态。研究使用了2008–2016年间5个有风电场区域与9个无风电场区域的多年度种群调查数据。此外，我们分别拟合逻辑回归模型与负二项回归模型，用以检验2016年风电场邻近度对物种出现率与种群丰度的影响，并在两个模型中纳入局地连通性与栖息地可利用性作为预测变量。
3. 结果显示整体种群呈下降趋势，但有风电场区域的下降趋势显著更剧烈：年均下降率达21.0%，而无风电场区域仅为5.8%。
4. 2016年杜氏百灵的出现率与种群丰度随种群隔离程度升高而降低，随与风电场的距离增加而提升。
5. 上述结果凸显了种群隔离与风电场邻近度对杜氏百灵种群参数的负面影响。结合研究区域内该物种的集合种群（metapopulation）结构，本研究确定了风电场的4.5km阈值距离，超过该距离的区域，杜氏百灵种群将不受风电场影响。
6. 研究总结与应用启示：本研究明确了风电场对小型鸟类的负面影响，并提出了未来风电项目设计中应参考的4.5km阈值距离。此外，我们提出了一种基于种群动态、物种丰度及与风电场相关的出现率变化的分析方法，可用于评估风电场对小型鸟类的影响。