Doctoral Dissertation Research: Spatial and Temporal Configurations of Potential Distributions of Grassland Sparrows

博士论文研究：草原麻雀潜在分布的时空配置

• 批准号: 1131644
• 负责人: Townsend Peterson
• 金额: $ 1.17万
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-15 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1131644&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Spatial; Temporal

One problem that has vexed biogeographers and others interested in the distribution of different species is the difficulties that many species have in adapting when their habitats are changed by human activity or other forces. A related problem is the difficulty in monitoring the number and distribution of these species. One such species is Henslow's sparrow (Ammodramus henslowii), a grassland-nesting bird that is found in the central U.S. and nearby parts of Canada. This doctoral dissertation research project will take a multifaceted view of Henslow's sparrow distributional biology, focusing on improving understanding about how populations respond to broad-scale habitat changes and of the extent to which human activities affect the amount and distribution of its breeding habitat, particularly in Midwestern grasslands. Henslow's sparrows currently have a distribution that is patchy and local; although the limits of the species' range are perhaps well-known, existing surveys are largely confined to roads. Current information therefore may neither represent all available habitat, such as grasslands in airfields, military bases, and reclaimed surface mines, nor does it accurately estimate population trends. No detailed map of suitable habitat for the full breeding distribution currently is available. The doctoral student will use ecological niche models to produce a detailed distributional understanding by identifying key environmental variables and characterizing the amount of suitable breeding habitat and its spatiotemporal dynamics within a patch-matrix framework while taking into account landscape heterogeneity and habitat patch characteristics produced by year-to-year disturbance dynamics. Once these models have been validated through independent field surveys, year-to-year variation of the extent and arrangement of suitable patches will be analyzed. This analysis will provide insight and explanation for the broad-scale nomadic behavior documented in earlier studies of the breed. These models also will be used to evaluate how well current survey techniques function to sample Henslow's sparrow breeding habitat. The student will evaluate these models by summarizing the amount of suitable grasslands in patches immediately surrounding routes identified by the North American Breeding Bird Survey and by comparing it to the broader distribution of this habitat (produced by the niche models) and the proportion of habitat types within the landscape matrix (using land-cover maps).Henslow's sparrows have very specific nesting habitat requirements that make them relatively good indicators of healthy tallgrass prairie ecosystems. Like many other obligate grassland species, they have suffered severe habitat loss as a result of fragmentation and conversion of grasslands, a loss estimated to have exceeded 99 percent across North America. Unlike a few other species that adapted easily to these changes, Henslow's sparrows have not responded well across their breeding range, and they have exhibited significant population declines over the last century. Recent studies have shown that this species does not return consistently to patches of habitat from year to year, which makes management of their habitat more difficult. This project will make significant contributions to the assessment of Henslow's sparrow populations and trends. The project also will provide a test of the capability of current survey techniques to effectively survey rare species and spatially limited habitat types. The project also will facilitate evaluation of recommendations for habitat management that more effectively accommodate the nomadic behavior as well as the amount, distribution, arrangement, or disturbance dynamics of this habitat at landscape scales. The results of this project therefore will potentially affect how species like Henslow's sparrows are managed and will prompt reevaluation of population trend estimates or habitat availability for other, similar species. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.

困扰生物地理学家和其他对不同物种分布感兴趣的人的一个问题是，当许多物种的栖息地被人类活动或其他力量改变时，它们难以适应。一个相关的问题是难以监测这些物种的数量和分布。其中一个物种是亨斯洛麻雀（Ammodramus henslowii），一种在草原筑巢的鸟，发现于美国中部和加拿大附近的部分地区。本博士论文研究项目将从多方面研究亨斯洛的麻雀分布生物学，重点是提高对种群如何应对大范围栖息地变化的理解，以及人类活动在多大程度上影响其繁殖栖息地的数量和分布，特别是在中西部草原。亨斯洛麻雀目前的分布是不完整的和地方性的；虽然这种物种的活动范围可能是众所周知的，但现有的调查主要局限于道路。因此，目前的信息既不能代表所有可用的栖息地，如机场、军事基地和开垦的地面地雷的草原，也不能准确估计人口趋势。目前没有详细的适合繁殖分布的栖息地地图。该博士生将利用生态位模型，通过识别关键环境变量，在斑块矩阵框架内描述适宜繁殖栖息地的数量及其时空动态，同时考虑到景观异质性和栖息地斑块特征的逐年扰动动态，从而产生详细的分布理解。一旦这些模型通过独立的实地调查得到验证，将分析合适斑块的范围和排列的逐年变化。这一分析将为早期对该品种的研究中记录的大规模游牧行为提供见解和解释。这些模型还将用于评估当前的调查技术对亨斯洛麻雀繁殖栖息地的取样效果。学生将通过总结北美繁殖鸟类调查确定的路线周围的补丁中合适草原的数量，并将其与该栖息地的更广泛分布（由生态位模型产生）和栖息地类型在景观矩阵中的比例（使用土地覆盖图）进行比较，来评估这些模型。亨斯洛麻雀有非常特殊的筑巢栖息地要求，这使它们成为健康的高草草原生态系统的相对良好的指标。像许多其他专性草地物种一样，由于草地的破碎化和转换，它们遭受了严重的栖息地丧失，据估计，整个北美的损失率超过99%。不像其他一些很容易适应这些变化的物种，亨斯洛麻雀在它们的繁殖范围内没有很好的反应，在上个世纪，它们的数量显著下降。最近的研究表明，这种物种不会每年都回到栖息地，这使得它们的栖息地管理变得更加困难。该项目将对评估亨斯洛麻雀的数量和趋势作出重大贡献。该项目还将测试当前调查技术有效调查稀有物种和空间有限的生境类型的能力。该项目还将促进对栖息地管理建议的评估，以更有效地适应游牧行为以及景观尺度上栖息地的数量、分布、安排或干扰动态。因此，这个项目的结果可能会影响像亨斯洛麻雀这样的物种的管理方式，并将促使对其他类似物种的种群趋势估计或栖息地可用性的重新评估。作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立研究生涯。