• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Breeding bird use of grasslands enrolled in the Conservation Reserve Program in the northern Great Plains.
【24h】

Breeding bird use of grasslands enrolled in the Conservation Reserve Program in the northern Great Plains.

机译：大平原北部自然保护区计划中登记的草原的鸟类繁殖。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

This dissertation examines bird use of grasslands enrolled in the Conservation Reserve Program (CRP) in four states in the northern Great Plains. Many methods are available to survey birds in grasslands, but there is no consensus as to which method is the most suitable. During two years (1995 and 2000), this study evaluated whether total-area count methodology was an effective alternative to point counts in estimating occurrence and abundance of breeding birds using CRP grasslands. Less effort was required using total-area counts than point counts. Seventeen of 26 bird species showed greater odds of detection using total-area counts than point counts; one species showed greater odds of detection using point counts. Density estimates for point counts were generally higher and more variable than density estimates for total-area counts.;Management disturbances of CRP grasslands generally are not allowed unless authorized to provide relief to livestock producers during drought and other natural disasters or to improve the quality of CRP vegetation. This study assessed the effects of haying on 20 bird species in CRP grasslands between 1993 and 2008. Breeding bird densities were compared in idled and hayed fields to evaluate changes 1-4 years after haying. Haying had either positive or negative effects on birds, depending on the species, county, and number of years after the disturbance. The responses of some species changed direction as the fields recovered from haying. This study provides important information on the strength and direction of changes in bird populations following haying.;The Brown-headed Cowbird is an obligate brood parasite. Cowbirds reach their highest abundance in the northern Great Plains. This study examines cowbird brood parasitism and densities in the northern Great Plains between 1990 and 2006. The overall rate of parasitism in 1902 passerine nests was moderate but the rate of multiple parasitism among parasitized nests was heavy. Nests found in CRP grasslands within areas of higher female cowbird abundance had higher rates of cowbird parasitism than those in areas of lower cowbird abundance. Densities of female cowbirds were positively related to densities and richness of other birds in the community.
机译：本论文研究了大平原北部四个州的自然保护区计划（CRP）中登记的草地的鸟类利用情况。有许多方法可以用来调查草原上的鸟类，但对于哪种方法最合适尚无共识。在两年中（1995年和2000年），这项研究评估了在使用CRP草原估算繁殖鸟类的发生和数量时，总面积计数方法是否是点计数的有效替代方法。使用总面积计数比点计数所需的精力更少。在26种鸟类中，有17种使用总面积计数的可能性大于点计数的可能性；一种物种使用点计数显示出更高的检测几率。点计数的密度估计值通常比总面积计数的密度估计值更高且变化更大。;除非允许在干旱和其他自然灾害期间减轻牲畜生产者的负担或提高其质量，否则通常不允许对CRP草原进行管理干扰。 CRP植被。这项研究评估了1993年至2008年间，干草对CRP草地上20种鸟类的影响。比较了闲置和干草田中繁殖鸟类的密度，以评估干草在1-4年后的变化。干草对鸟类有正面或负面影响，具体取决于物种，县和干扰后的年限。随着干草的恢复，一些物种的反应改变了方向。这项研究提供了关于干草后鸟类种群变化的强度和方向的重要信息。棕头牛鸟是专性的繁殖寄生虫。在大平原北部，牛bird的数量达到最高。这项研究调查了1990年至2006年之间大平原北部的牛鸟巢寄生和密度。1902年雀形燕窝的总寄生率中等，但被寄生的巢中的多重寄生率很高。在雌性牛female丰度较高区域内的CRP草地中发现的巢，比低牛鸟丰度区域中的巢具有较高的牛鸟寄生率。雌性牛bird的密度与社区中其他鸟的密度和丰富度呈正相关。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号