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. 风电场对鸟类种群影响的评估通常基于碰撞死亡记录，但该方法可能低估风电场对小型鸟类的影响。本研究针对受威胁的小型雀形目鸟类（Passerine）物种——杜氏百灵（Chersophilus duponti），评估风力涡轮机对其出现率、种群丰富度及种群趋势的影响。据我们所知，本研究是首批利用多风电场的时间序列数据探究风电场对种群趋势影响的研究之一。
2. 我们借助TRIM（Trend & Indices for Monitoring data，监测数据趋势与指数工具）软件拟合转换线性趋势模型以估算种群趋势：采用2008–2016年间的多年监测调查数据，涵盖5个受风电场影响的种群与9个未受风电场影响的种群。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年风电场邻近度对该物种种群出现率与丰富度的影响；并将局地连通性与生境可获得性的估算值作为预测变量纳入两类模型。
3. 研究结果显示种群整体呈负增长趋势，但在有风电场分布的区域，种群衰退程度显著更高：无风电区域的年均种群下降率为5.8%，有风区域则达21.0%。
4. 2016年杜氏百灵的种群出现率与丰富度受到种群隔离程度的负面影响，同时与风电场的距离呈正相关影响。
5. 上述结果凸显了种群隔离与风电场邻近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4.5公里阈值距离，超过该距离的区域内，杜氏百灵种群将不受风电场影响。
6. 总结与应用：本研究强调了风电场对小型鸟类的负面影响，并提出了4.5公里的阈值距离，该距离应在未来风能项目的设计中予以考量。此外，我们提出了一种基于种群趋势、物种丰富度及与风电场相关的出现率变化的分析方法，该方法可用于评估风电场对小型鸟类的影响。