Number of White Stork Ciconia ciconia Nests in Latvia Between 1934 and 2014

Q4 Multidisciplinary
Māra Janaus, Andris Dekants
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引用次数: 0

Abstract

Abstract The article summarises the results obtained during the 7 th International White Stork Census 2014 in Latvia as well as analyses of changes since 1934. More than 2000 participants were involved in the census. About 14,000 pairs of white storks (WS) were found nesting in Latvia in 2014, i.e. about 52% more than in 1934, and about 25% more than in 1994 and 2004. The breeding density was one of the highest in the breeding area — on average, 21.7 occupied nests/100 km 2 territory and 60.8 nests/100 km 2 agricultural lands. The proportion of occupied nests in 2014 was 90.1%, and the proportion of successful ones — 95.7%. The average number of raised chicks decreased from 2.7 in occupied nests and 2.8 in successful nests in 1934 to 2.1 and 2.4 in 2014, correspondingly. The main reasons for this decrease were deterioration of feeding conditions (amount and availability of food, as well as the regionally growing use of agricultural chemicals). Since 1934, considerable changes in WS nest location and human aid in their construction have been observed. Eighty years ago, an absolute majority of nests (about 80%) were built with human aid (artificial nest support) on trees; whereas in 2014, only 3.5% such nests were registered. Most nests (64.8%) in 2014 were built on electric poles without artificial support. According to observations after 2014, the growth of the breeding population of WS in Latvia has come to an end, and even a slight regional decrease has been observed. Nevertheless, at present, there are no reasons to consider the local breeding population of the WS as being endangered and vanishing.
1934年至2014年间拉脱维亚白鹳巢的数量
摘要本文总结了2014年拉脱维亚第七次国际白鹳普查的结果,并分析了自1934年以来的变化。2000多名参与者参与了这次人口普查。2014年,拉脱维亚发现了大约14000对白鹳(WS)筑巢,比1934年增加了52%,比1994年和2004年增加了25%。孳生密度在孳生区内最高,平均每100 km2有21.7个巢,平均每100 km2有60.8个巢。2014年占巢率为90.1%,成功占巢率为95.7%。平均饲养雏鸡数量分别从1934年的占巢2.7只和成功巢2.8只下降到2014年的2.1只和2.4只。减少的主要原因是饲养条件的恶化(粮食的数量和可得性,以及区域内农用化学品的使用增加)。自1934年以来,观察到WS巢穴位置和人类帮助其建造的重大变化。80年前,绝大多数鸟巢(约80%)是在人类的帮助下(人工筑巢)在树上建造的;而在2014年,只有3.5%的此类巢穴被登记在案。2014年大多数鸟巢(64.8%)建在没有人工支撑的电线杆上。根据2014年之后的观察,拉脱维亚WS繁殖种群的增长已经结束,甚至出现了轻微的区域性下降。然而,现时并无理由认为本地的白鱀豚繁殖种群已濒临灭绝。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
CiteScore
0.70
自引率
0.00%
发文量
61
审稿时长
20 weeks
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