Dissertation Research: Future changes in California bird communities projected from century-scale resurveys

这个项目将研究为什么加利福尼亚的鸟类出现在与100年前不同的地方。这些信息将被用来预测鸟类将如何应对未来气候和栖息地的变化，从而实现更好的保护规划。研究人员将利用一种独特的历史资源：从1900年到1945年在加利福尼亚州每个主要生态区进行的鸟类系统调查。这些调查是在经历了气候、农业发展和城市化变化的地点进行的。洛杉矶地区的30个地点将被重新勘测。所得数据将被添加到已在内华达山脉、海岸山脉、中央山谷和莫哈韦沙漠重新调查的290个地点的数据集。鸟类对每个地点变化的反应将被用来预测未来对气候和土地利用变化的反应。这项研究将加深我们对气候和土地利用变化如何影响鸟类的理解。具体地说，它将测试土地利用的变化是否会加剧气候变化带来的问题，或者帮助一些鸟类在本来可以避免的地方生活。这个项目对保护规划很重要，将为两名学生提供培训和指导。这项研究将使用独特的历史资源(由Joseph Grinnell和他的同事进行的20世纪早期鸟类调查)与当代重新评估相结合，量化气候和土地利用变化的影响如何改变加州的鸟类分布。这些措施将用于预测未来气候和土地利用变化情景下的鸟类分布情况。在农业发达的中央山谷的30个地点以及内华达山脉、海岸山脉和莫哈韦沙漠的260个相对受保护的地点已经完成了重新调查。该项目将重新调查洛杉矶地区的另外30个地点，提供一种衡量鸟类对更大的变暖和城市化的反应的指标，而不是目前的数据集。通过量化过去一个世纪鸟类占有率的变化是如何由气候和土地利用协变量驱动的，这项研究将基于对时间变化的直接测量来预测鸟类对未来气候和土地利用变化情景的反应。预测将被用来探索未来哪些鸟类群体预计会经历范围扩大或收缩，以及这是否会导致非类比鸟类群落的创建。

This project will examine why birds in California occur in different places than they did 100 years ago. This information will be used to predict how birds will respond to future changes in climate and habitat, enabling better conservation planning. Researchers will make use of a unique historic resource: systematic surveys of birds conducted in every major ecological region of California from 1900 to 1945. These surveys were conducted at sites that have since experienced changes in climate, agricultural development, and urbanization. Thirty sites in the Los Angeles area will be re-surveyed. The resulting data will be added to a dataset of 290 sites already re-surveyed in the Sierra Nevada, Coast Ranges, Central Valley, and Mojave Desert. Measures of how birds have responded to changes at each site will be used to predict future responses to climate and land use change. This study will enhance our understanding of how combined changes in climate and land use impact birds. Specifically, it will test whether changes in land use exacerbate problems from climate change or help some birds to live in places they would have otherwise avoided. This project is important for conservation planning and will provide training and mentoring of two students.This study will use a unique historical resource (early 20th century bird surveys conducted by Joseph Grinnell and colleagues) in conjunction with contemporary resurveys to quantify how the effects of climate and land-use change have altered bird distributions in California. These measures will be used to project bird distributions under future scenarios of climate and land-use change. Re-surveys have already been completed at 30 sites in the agriculturally-developed Central Valley, and 260 relatively protected sites in the Sierra Nevada, Coast Ranges, and Mojave Desert. This project will re-resurvey an additional 30 sites in the Los Angeles area, providing a measure of how birds have responded to greater warming and urbanization than is represented in the current dataset. By quantifying how changes in bird occupancy over the past century are driven by climate and land-use covariates, this study will then project bird responses to future scenarios of climate and land-use change based on direct measures of temporal change. Projections will be used to explore which groups of birds are expected to experience range expansions or contractions in the future, and whether this will result in the creation of no-analog bird communities.