Factors affecting the spatial distribution of San Joaquin kit foxes
Factors affecting the spatial distribution of San Joaquin kit foxes
复制标题
影响圣华金狐空间分布的因素
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
B. Cypher
中科院分区：
文献类型：
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作者：
G. Warrick;B. Cypher
确定影响或限制濒危物种分布的因素可能具有重要的保护意义。1988年至1995年，我们调查了海军石油储备在加州（NPRC）的31,400公顷的面积内的濒危圣华金赤狐（大耳狐）的空间分布与赤狐的捕获率栖息地因素，较大的捕食者的访问率，猎物计数。1981年至1995年，NPRC的一小部分（11，500公顷）的捕获率也与生境因素有关。在1981-82年，赤狐的分布相对均匀，因此回归模型只能解释捕获率的6%的空间变异。之后，赤狐的分布变得更加有限，模型解释了捕获率变化的36-60%。捕获率与地形的崎岖性呈负相关，围栏区域（限制公众进入和没有牲畜放牧; P < 0.001）内捕获率较低，而焚烧区捕获率往往较高（P < 0.001）。1987年以后，捕获率通常与油田开发呈负相关。草原狼（Canis latrans）是赤狐的主要捕食者，在围栏区域内的访问率较高（P ≤ 0.034）。捕获率呈负相关（r 132 =-0.22，P = 0.01）与郊狼访问率在1992-95年。山猫（猞猁rufus）的位置捕获和访问气味站重叠很少与工具箱狐狸的捕获位置。兔形动物（一个重要的猎物项目）计数与燃烧呈负相关，1992年至1995年，兔形动物计数与油田开发呈正相关。在1988- 1991年（r77 =-0.09，P = 0.44）或1992- 1995年（r77 = 0.15，P = 0.18），捕获率与兔形目动物计数不相关。我们的研究结果表明，锦鸡儿和栖息地的因素之间的关系是有点灵活的，和锦鸡儿的空间分布主要不是由猎物丰度。捕食者密度和地形的崎岖性似乎是重要的潜在因素，在NPRC的锦囊狐的空间分布。
Determining the factors that influence or limit the distribution of endangered species can have important conservation implications. We investigated the spatial distribution of endangered San Joaquin kit foxes (Vulpes macrotis mutica) within a 31,400-ha area of the Naval Petroleum Reserves in California (NPRC) from 1988 to 1995 by relating capture rates of kit foxes to habitat factors, visitation rates of larger predators, and prey counts. Capture rates also were related to habitat factors on a smaller portion (11,500 ha) of NPRC from 1981 to 1995. Kit foxes were relatively evenly distributed in 1981-82, and regression models consequently explained only 6% of the spatial variation in capture rates. Afterwards, the distribution of kit foxes became more restricted, and models explained 36-60% of the variation in rates of capture. Capture rates were negatively associated with topographic ruggedness, were lower within a fenced area (limited public access and no livestock grazing; P < 0.001), and were often higher within burned areas (P < 0.001). After 1987, capture rates were usually negatively associated with oil-field development. Visitation rates of coyotes (Canis latrans), a major predator of kit foxes, were higher within the fenced area (P ≤ 0.034). Capture rates were negatively correlated (r 132 = -0.22, P = 0.01) with coyote visitation rates during 1992-95. Locations of bobcat (Lynx rufus) captures and visits to scent stations overlapped very little with capture locations of kit foxes. Counts of lagomorphs (a significant prey item) were negatively associated with burning, and between 1992 and 1995, lagomorph counts were positively associated with oil-field development. Capture rates were not correlated with lagomorph counts during 1988-91 (r 77 = -0.09, P = 0.44) or 1992-95 (r 77 = 0.15, P = 0.18). Our findings indicated the relation between kit foxes and the habitat factors studied was somewhat flexible, and the spatial distribution of kit foxes was not determined primarily by prey abundance. Predator density and topographic ruggedness appear to be important underlying factors governing the spatial distribution of kit foxes at NPRC.