• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >The Role of Body Size in the Foraging Strategies and Management of Avian Herbivores: A Comparison of Dusky Canada Geese (Branta canadensis occidentalis) and Cackling Geese (B. hutchinsii minima) Wintering in the Willamette Valley of Oregon.
【24h】

The Role of Body Size in the Foraging Strategies and Management of Avian Herbivores: A Comparison of Dusky Canada Geese (Branta canadensis occidentalis) and Cackling Geese (B. hutchinsii minima) Wintering in the Willamette Valley of Oregon.

机译：体型在鸟类食草动物觅食策略和管理中的作用：俄勒冈州威拉米特河谷越冬加拿大鹅（Branta canadensis occidentalis）和C鹅（B. hutchinsii minima）越冬的比较。

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

Body size explains much of the interspecific variation in the physiology, behavior, and morphology of birds, such as metabolic rate, diet selection, intake rate, gut size, and bill size. Based on mass-specific metabolic requirements and relative energetic costs of activities, being a certain body size has both advantages and disadvantages. In particular, avian herbivores such as geese possess a relatively simple digestive system, consume foods with low digestibility and poor nutrient content, and have increased energetic demands compared to other bird taxa; therefore, any effects of body size on foraging strategies should be readily apparent in this foraging guild. The influence of body size on the behavior and management of Canada Geese (Branta canadensis) and Cackling Geese (B. hutchinsii) as avian herbivores has not been well studied.;My dissertation explores the role of body size in comparative foraging behavior, habitat selection, and winter conservation planning for two congeneric geese, the Dusky Canada Goose (B. c. occidentalis; hereafter Duskys) and the Cackling Goose (B. h. minima; hereafter Cacklers). These two taxa share the same over-winter foraging environment (grass seed fields) in the same restricted geographic area (the Willamette Valley) during winter. Duskys and Cacklers differ by more than a factor of two in body size and have different relative bill sizes and social organization. Because of smaller body size, Cacklers have greater relative energy demands and less fasting endurance compared to Duskys; however, Cacklers have comparatively low energetic costs for flight and transport. Duskys, however, have higher total energy requirements than Cacklers. Additionally, Cacklers form large, high-density flocks and have a total over-wintering population size in the study area of about 200,000. Duskys occur in relatively small family groups and have a total over-wintering population size of about 13,000.;My study demonstrated that interspecific differences in body size between Cacklers and Duskys was associated with differences in foraging behavior, movements, and habitat selection. Cacklers foraged a greater percentage of time (30%) in all habitats and across the entire winter compared to Duskys. Cacklers had higher peck rates (up to 100 pecks min-1 greater) than Duskys in all foraging habitats expect pasture. The pecking rate of Cacklers was greatest in fields of young grass (200 pecks min-1), which may indicate that Cacklers had relatively high intake rates in this foraging habitat. Based on differences in foraging behavior among habitats, Cacklers may have the foraging strategy of energy intake maximizers, whereas the foraging strategy of Duskys is more towards time-energy expenditure minimizers, at least for part of the winter. Cacklers moved across the landscape very differently from Duskys, exhibiting less site fidelity and greater commuting distances to foraging areas. Cacklers showed a preference for young grass during all periods of the winter, reaffirming that Cacklers are specialized grazers on short green forage, whereas Duskys preferred young grass and pasture. Fields of young grass were the preferred foraging habitat of Cacklers, had less standing crop biomass, and may have enabled higher foraging efficiencies, which may have led to higher intake rates.;The ability of the landscape to support wintering geese changed across the winter because total available plant biomass fluctuated with the rate of grass regrowth. The estimated carrying capacity of the landscape for geese decline by almost one-half during mid-winter (mid-December to mid-February) compared to early winter or late winter periods. Although Cacklers have lower individual energy requirements compared to Duskys, due to a much larger target population size, Cacklers required 89% more foraging habitat than Duskys. Forage requirements encountered a bottleneck during mid-winter, when grass regrowth rates were low and day length was short. Commensurate with this pattern of forage availability, goose body condition declined during the mid-winter period. To support Pacific Flyway target populations for geese, approximately 18,000 ha of total grazing habitat in young and mature grass is needed in the Willamette Valley to support a total over-wintering population composed of 340,000 geese belonging to four subspecies.;The role of body size in influencing the foraging behavior and decisions of over-wintering geese has important implications for conservation planning of goose populations. Small-bodied Cacklers are selective in field choice, yet more likely to redistribute across the landscape. Disturbances ( e.g., hunting, hazing, or predation) will have a disproportionate effect on the movements of smaller-bodied geese compared to larger geese. These characteristics of Cacklers will make conservation planning to retain geese on public land more difficult. Coordinated management with private landowners and farming practices that maximize preferred goose foraging habitat on public lands may attract geese to utilize protected areas and minimize conflicts with agriculture in the Willamette Valley. Availability of resources during critical periods in winter is an important factor affecting the distribution of geese, but may affect small and large bodied geese differently. Management could be targeted during these critical time periods. By considering the role of body size in the context of life history characteristics, foraging behavior and habitat selection, appropriate management strategies can be developed and implemented to reduce the effects of agricultural depredation by geese, while promoting the future conservation of wintering geese in the Willamette Valley.
机译：体型可以解释鸟类生理，行为和形态的种间差异，例如新陈代谢率，饮食选择，摄入率，肠道大小和账单大小。基于特定于质量的代谢要求和活动的相对精力成本，确定的身材大小既有利又不利。尤其是，诸如鹅之类的鸟类食草动物具有相对简单的消化系统，食用消化率低且营养成分差的食物，并且与其他鸟类类群相比，其能量需求增加；因此，在这个觅食行会中，体重对觅食策略的任何影响都应该显而易见。体型对加拿大鹅（Branta canadensis）和and鹅（B. hutchinsii）作为食草动物的行为和管理的影响尚未得到很好的研究。；本论文探讨了体型在比较觅食行为，生境选择中的作用。 ，以及两只同类鹅的冬季保护计划，它们分别是Dusky加拿大鹅（B. c。occidentalis；以下称Duskys）和Cackling Goose（B。h。minima；以下称Cacklers）。在冬季，这两个分类单元在相同的受限地理区域（威拉米特谷）共享相同的冬季觅食环境（草种子田）。 Duskys和Cacklers的身材差异超过两倍，并且具有相对的账单尺寸和社会组织。由于体型较小，因此与Duskys相比，Cacklers具有相对较高的能量需求和较低的空腹耐力。然而，卡克勒在飞行和运输方面的能源成本相对较低。但是，昏暗的人比卡克勒斯拥有更高的总能量需求。另外，Ca虫形成大的高密度羊群，在研究区域内的总越冬种群数量约为200,000。昏暗的人发生在相对较小的家庭群体中，总的越冬人口总数约为13,000。我的研究表明，卡克勒和昏暗的人之间的体型差异与觅食行为，活动和生境选择的差异有关。与昏暗的天空相比，鸟在所有栖息地和整个冬季中觅食的时间比例更高（30％）。在所有觅食生境所期望的牧场中，鸟的啄食率更高（最多达100啄min-1）。 Cacklers的啄食率在幼草田中最大（200啄min-1），这可能表明Cacklers在该觅食生境中的采食率相对较高。基于栖息地之间觅食行为的差异，Cacklers可能具有能量摄入最大化的觅食策略，而Duskys的觅食策略则更倾向于时间能源消耗最小化，至少在冬季的一部分时间。 ckle鸟在整个地形上的移动与杜斯基斯截然不同，它们的场地保真度较低，到觅食区的通勤距离更大。整个冬季，Cacklers均偏爱幼草，这再次表明Cacklers是专门用短草料觅食的放牧者，而Duskys则偏爱幼草和牧场。幼草田是Cacklers的首选觅食生境，具有较低的作物生物量，并且可能提高了觅食效率，这可能导致更高的采食率。整个冬季，景观支持冬季鹅的能力有所变化，因为可用植物总生物量随草丛再生速率的变化而波动。与冬季初冬或冬季晚些时候相比，在冬季中旬（12月中旬至2月中旬），估计的鹅的景观承载力下降了近一半。尽管与Du斯基犬相比，Ca鼠具有较低的个体能量需求，但由于目标种群更大，,鼠需要比Du斯基鼠多89％的觅食栖息地。牧草的需求在冬季中旬遇到了瓶颈，当时草草的再生长率低，日长短。与这种饲料供应模式相对应的是，在冬季中期，鹅的身体状况有所下降。为了支持太平洋飞鹅的鹅群目标，威拉米特山谷需要大约18,000公顷的年轻人和成熟草的总放牧栖息地，以支持由4个亚种的340,000只鹅组成的总越冬种群。影响过冬鹅的觅食行为和决策对鹅种群的保护规划具有重要意义。小型钩钩虫在田间选择上具有选择性，但更有可能在整个景观中重新分布。干扰（例如打猎，阴霾）（或捕食）与大鹅相比，对小体鹅的运动会有不成比例的影响。卡勒克勒犬的这些特征将使保护计划难以将鹅保留在公共土地上。与私人土地所有者的协调管理和农业实践可以最大化鹅在公共土地上的觅食栖息地，这可能会吸引大雁利用保护区，并最大程度地减少与威拉米特山谷的农业冲突。冬季关键时期的资源可利用性是影响鹅的分布的重要因素，但对大体鹅和大体鹅的影响可能不同。在这些关键时期内可以有针对性地进行管理。通过考虑体型在生活史特征，觅食行为和栖息地选择方面的作用，可以制定和实施适当的管理策略来减少鹅对农业的掠夺，同时促进将来在威拉米特的越冬鹅的保护谷。

著录项

  • 作者

    Mini, Anne E.;

  • 作者单位

    Oregon State University.;

  • 授予单位 Oregon State University.;
  • 学科 Agriculture Wildlife Management.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 195 p.
  • 总页数 195
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
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