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Analysis of relationships between food conditions and reproductive parameters in the Japanese serow (Capricornis crispus) for its conservation

为保护日本羚羊 (Capricornis Cripus) 的食物条件与繁殖参数之间的关系分析

基本信息

批准号：
14580605
负责人：
OCHIAI Keiji
金额：
$ 1.86万
依托单位：
Natural History Museum and Institute, Chiba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2005
项目状态：
已结题

项目摘要

I conducted a survey to examine relationships among population density, territory size, winter food quantity and quality, and reproductive success for adult females in the Japanese serow, Capricornis crispus, in three study areas : Shimokita (0-240 m above sea level) in Aomori Prefecture, Asahi (500-1100 m) in Yamagata Prefecture, and Kamikochi (1500-2000 m) in Nagano Prefecture. Mean population densities were 14.2 individuals/km^2 at Shimokita, 7.4 /km^2 at Asahi, and 1.6 /km^2 at Kamikochi. Mean annual territory sizes for adult females were 10.5 ha at Shimokita, 29.8 ha at Asahi, and 49.8 ha at Kamikochi. I determined reproductive success by noting which adult females gave birth, and whose overwintering kids survived until May. Mean reproductive success was 38.1% at Shimokita, 29.6% at Asahi, and 15.8% at Kamikochi. To assess winter food quantity, I defined the total basal area (mm^2) at snow surface of trunks of edible trees along new serow traces per 10 m (× 1 m width) on the snow as the food availability index (FAI). The FAI was 1871.4 at Shimokita, 1236.2 at Asahi, and 869.8 at Kamikochi. I defined the number of fresh feeding signs by serow bites on trees found along new serow traces per 10 m (× 1 m width) on the snow as feeding efficiency (FE). The FE value was 59.1 at Shimokita, 38.2 at Asahi, and 10.4 at Kamikochi. I found correlations between territory size and population density, between FAI and FE, between FAI and territory size, and between FAI and reproductive success. These results suggest that a small range size and high reproductive success, which are supported by better food supply, result in a high population density at Shimokita, where the elevation is low and the climatic conditions milder, whereas Kamikochi is a subalpine area with severe winter climatic conditions.

笔者在青森县下田（海拔0-240米）、山形县Asahi（海拔500-1100米）和长野县kamikkochi（海拔1500-2000米）三个研究区域进行了一项调查，研究了人口密度、领土面积、冬季食物数量和质量以及成年雌性山羊的繁殖成功率之间的关系。平均种群密度分别为：下基多14.2只/km^2，朝日7.4只/km^2，上高知1.6只/km^2。雌成虫的年平均领地面积分别为下田10.5 ha、朝日29.8 ha和上高知49.8 ha。我通过观察哪些成年雌性生育，以及哪些越冬的孩子能活到5月来确定繁殖成功率。下田的平均繁殖成功率为38.1%，朝日为29.6%，上高知为15.8%。为了评估冬季食物量，我将雪上每10米（× 1米宽）新雪迹沿线可食树木树干在雪表面的总基底面积（mm^2）定义为食物可用性指数（FAI）。下田的FAI是1871.4，朝日是1236.2，上高知是869.8。我将积雪上每10米（× 1米宽）的新雪痕上发现的树木上的雪咬痕迹的数量定义为进食效率（FE）。下田的FE值为59.1，朝日为38.2，上高知为10.4。我发现领土大小与人口密度、FAI与FE、FAI与领土大小、FAI与繁殖成功率之间存在相关性。这些结果表明，下田地区海拔低，气候条件温和，种群密度高，繁殖成功率高，并有较好的食物供应支持，而上高地地区是亚高山地区，冬季气候条件恶劣。