DETERMINANTS OF SPATIAL DISTRIBUTION OF ROCKY MOUNTAIN BIGHORN SHEEP
DETERMINANTS OF SPATIAL DISTRIBUTION OF ROCKY MOUNTAIN BIGHORN SHEEP
复制标题
落基山大角羊空间分布的决定因素
DOI：
--
复制
发表时间：
1975
期刊：
影响因子：
--
通讯作者：
W. D. Kitts
中科院分区：
文献类型：
--
作者：
N. H. Shannon;R. Hudson;V. C. Brink;W. D. Kitts
研究了不列颠哥伦比亚省东南部落基山大角羊（Ovis canadensis）幼羊群的时空分布。通过简单和偏相关分析，发现季节分布与坡度、坡度变化、与逃逸地形的距离、高程、坡向、森林覆盖、灌木生产力、美味草生物量、美味草氮含量、离盐距离、雪深等11个环境变量相关。各个环境因素对分布的影响在全年有所不同。这些变量加起来约占观察到的大角羊数量面积变化的65%。多元回归方程的残差映射揭示了极端高估或低估的离散区域。LJ WILDL。管理。39(2):387-401生活在季节性变化环境中的动物经常分散或迁移，以避免或更好地忍受周期性的困难。这一点在落基山大角羊和其他山地有蹄类动物身上得到了很好的证明，它们的分布具有明显的季节性变化。虽然这些运动已经被记录下来，并在许多研究中进行了比较（Simmons 1961, Blood 1963），但很少有人尝试量化分布的可预测性以及影响分布的众多变量的相对重要性。这些信息是了解动物与环境关系的基础。栖息地选择是动物对构成动物“固有环境”或“相关环境”的大量往往相互依存的变量的复杂反应的一种表达。这些变量可能是内在的，取决于动物的生理和行为状态，也可能是外在的，取决于来自环境的非生物和生物特征的线索。本研究的目的是描述落基山大角羊种群空间分布的季节变化，确定这些变化与季节变化的环境的关系程度，并推断动物对每种环境变量的反应的偏差如何反映生理和行为特征的季节变化。由于变量之间存在复杂的相互联系，因此采用多重相关结合残差映射技术来分析面积变化（Berry and Marble 1968）。我们感谢鱼类和野生动物处、放牧司和不列颠哥伦比亚省政府农业部的财政支持。R. Orich和L. Mather提供了宝贵的技术援助。这项研究是资深作者的理学硕士论文的一部分。研究区域和人口研究区域，由Demarchi详细描述（未发表的数据，英国现在地址：阿尔伯塔大学农林学院动物科学系，埃德蒙顿，阿尔伯塔T6G 2E3）。j . Wildl。《管理》39(2):1975 387本内容下载自157.55.39.100,2016年8月25日周四06:31:31 UTC所有使用须遵守http://about.jstor.org/terms 388大角羊的空间分布Shannon等人的lumbia鱼类和野生动物分支，维多利亚)，集中在不列颠哥伦比亚省东南部落基山脉海沟地区一个重要的大型猎物冬季范围。它的南面和东面是落基山脉，西面是库特尼河谷。6000公顷的范围在南部和西部是由威格瓦姆河和埃尔克河形成的深深的峡谷（图1）。气候上，该地区被认为是大陆性的，年平均气温约为6摄氏度，海拔933米的最低和最高气温分别为-34摄氏度和+39摄氏度。该地区年降水量约为64厘米，全年分布相当均匀。研究期间（1971-72年冬季）的降雪量异常大，为209厘米（不列颠哥伦比亚省农业部，1972年）。该地区包括大型冰川沉积的冲积阶地，低起伏的岩石丘陵，崎岖的悬崖和冰碛。冬天的山脉在梯田（高地）上。1060米)和更低的斜坡；夏季山脉延伸至布洛德伍德山（Mount Broadwood）的高山地区。2500米)。冬季野生动物出没的大部分地区都是1931年的一场大火造成的。黄松(Pinus ponderosa) -花旗冷杉（Pseudotsuga menziesii）森林的移除导致了河岸上几个相对稳定的草地和南部和西部斜坡上几个灌木阶段的产生。优势灌木为沙木（Amelanchier alnifolia）、红杉（ceanothus sanguineus）、雪莓（Symphoricarpos albus）、杜鹃（Apocynum androsaemifolium）和羊莓（Shepherdia canadensis）。在这些斜坡上也有丰富的道格拉斯枫。重要的牧草包括无须小麦草（Agropyron inerme）、肯塔基蓝草（Poa pratensis）、六月草（Koeleria cristata）和爱达荷羊茅（Festuca idahoensis）。蓍草（Achillea millefolium）、夹竹桃（phlox caespitosa）和马属植物（Monarda menthaefolia）是主要草本植物。夏季山脉支持各种草的生长，其中最丰富的是高山蓝草（Poa alpina），羊茅（Festuca ovina）和细长的小麦草（Agropyron trachycaulum）。其中莎草（Carex spp.）、灯芯草（Juncus parryi）和蕨类植物（eriogonum umellatum）、白猫蹄草（Antennaria alpina）、白杉木（dryas octopetala）和蓍草丰富。野牛莓、雪莓和柳树在亚高山地区也很重要。研究区有大量的大角羊，特别是在冬季（约200年），麋鹿（Cervus canadensis）和骡鹿（Odocoileus hemionus）也很常见。自1954年以来，除了每年4月至2月有几匹马在该地区活动外，该地区没有家畜放牧。
Temporal and spatial distributions of ewe-juvenile groups of Rocky Mountain bighorn sheep (Ovis canadensis) in southeastern British Columbia were studied throughout one annual cycle. With simple and partial correlation analyses,, seasonal distribution was related to 11 environmental variables: slope, changes in slope, distance to escape terrain, elevation, aspect, forest cover, shrub productivity, biomass of palatable grasses, nitrogen content of palatable grasses, distance from salt, and snow depth. The influence of individual environmental factors on distribution varied throughout the year. Together the variables accounted for approximately 65 percent of the observed areal variation in counts of bighorn sheep. Mapping of the residuals of the multiple regression equations revealed discrete areas of extreme overor underestimation. LJ WILDL. MANAGE. 39(2):387-401 Animals living in a seasonally varying environment frequently disperse or migrate in order to avoid or better endure periodic hardships. This is well demonstrated by Rocky Mountain bighorn sheep and other mountain ungulates which show distinct seasonal changes in distribution. Although these movements have been documented and compared in a number of studies (Simmons 1961, Blood 1963), fewer attempts have been made to quantify the predictability of distribution and the relative importance of the numerous variables which affect it. Such information is basic to understanding the animal in relation to its environment. Habitat selection is an expression of a complex response of animals to a large number of often interdependent variables which make up the "Umwelt" or "relevant environment" of the animal. These variables may be intrinsic, dependent on the physiological and behavioral status of the animal, or extrinsic, dependent on cues from abiotic and biotic features of the environment. The objective of the present study was to describe seasonal changes in the spatial distribution of a population of Rocky Mountain bighorn sheep, to determine the extent to which these were related to the seasonally changing environment, and to infer how seasonal changes in physiological and behavioral characteristics may be reflected in a biasing of the response of animals to each of the environmental variables. Since variables existed in complex inter-connection, multiple correlation coupled with residual mapping techniques were employed to analyze areal variations (Berry and Marble 1968). We thank the Fish and Wildlife Branch, the Grazing Division, and the Department of Agriculture of the Government of British Columbia for financial support. R. Orich and L. Mather provided valuable technical assistance. This study is part of a Master of Science thesis by the senior author. STUDY AREA AND POPULATION The study area, described in detail by Demarchi (Unpublished data, British CoPresent address: Department of Animal Science, Faculty of Agriculture and Forestry, University of Alberta, Edmonton, Alberta T6G 2E3. J. Wildl. Manage. 39(2):1975 387 This content downloaded from 157.55.39.100 on Thu, 25 Aug 2016 06:31:31 UTC All use subject to http://about.jstor.org/terms 388 SPATIAL DISTRIBUTION OF BIGHORN SHEEP Shannon et al. lumbia Fish and Wildlife Branch, Victoria), was centered on an important big game winter range in the Rocky Mountain Trench region of southeastern British Columbia. It was bounded on the south and east by the Rocky Mountains and on the west by the Kootenay River Valley. The range of 6,000 ha was bordered on the south and west by a deeply dissected canyon formed by the Wigwam and Elk Rivers (Fig. 1). Climatically, the region is considered continental with an annual mean temperature of about 6 C. Minimum and maximum temperatures recorded at 933 m elevation were -34 C and +39 C. The area receives about 64 cm precipitation annually, distributed rather uniformly throughout the year. Snowfall recorded during the study (winter of 1971-72) was unusually heavy, 209 cm (British Columbia Dept. Agric. 1972). The area included large glacierdeposited alluvial terraces, low rolling rocky knolls, and rugged cliffs and moraines. The winter range was on the terraces (elev. 1,060 m) and lower slopes; the summer range extended to the alpine areas of Mount Broadwood (elev. 2,500 m). Much of the area used by wildlife in winter was created by a large fire in 1931. Removal of ponderosa pine (Pinus ponderosa) -Douglas fir (Pseudotsuga menziesii) forests resulted in the production of relatively stable seral grasslands on the river benches and seral shrub stages on the south and westerly slopes. Saskatoon (Amelanchier alnifolia), redstem ceanothus (Ceanothus sanguineus), snowberry (Symphoricarpos albus), dogbane (Apocynum androsaemifolium), and buffaloberry (Shepherdia canadensis) were the dominant shrubs. Douglas maple (Acer glabrum) was also abundant on these slopes. Important grasses included beardless wheatgrass (Agropyron inerme), Kentucky bluegrass (Poa pratensis), junegrass (Koeleria cristata), and Idaho fescue (Festuca idahoensis). Yarrow (Achillea millefolium), phlox (Phlox caespitosa), and horsemint (Monarda menthaefolia) were the principal forbs. The summer range supported a varied growth of grasses, most abundant of which were alpine bluegrass (Poa alpina), sheep fescue (Festuca ovina), and slender wheatgrass (Agropyron trachycaulum). Sedges (Carex spp.), rushes (Juncus parryi), and the forbs, sulphur eriogonum (Eriogonum umbellatum), white pussytoes (Antennaria alpina), white dryas (Dryas octopetala), and yarrow, were abundant. Buffaloberry, snowberry, and willow (Salix spp.) were also important in the subalpine region. The study area supported large numbers of bighorn sheep, particularly in winter (ca. 200), and elk (Cervus canadensis) and mule deer (Odocoileus hemionus) were common. The range had not been grazed by domestic livestock since 1954 except for a few horses which occupied the area annually from April to February.