麋鹿鹿角脱落、群主更替、产仔的年节律及其环境影响因子

本文在2014—2016年三个冬季(12月—翌年2月)收集了北京南海子麋鹿苑半散放麋鹿自然脱落的角，并观察和记录了2015—2017年发情期(5—9月)群主更替和2016—2018年产仔期(3—7月)麋鹿幼仔出生情况，结合2014—2018年年平均气温、季平均气温、月平均气温、年降雨量、雨季开始时间、种群密度等环境因子，对鹿角脱落、群主更替、产仔等繁殖特征的年节律及其环境影响因子进行了研究。结果表明：1)麋鹿鹿角脱落、群主更替、产仔的年节律均存在年际差异。2)鹿角脱落时间为12月开始，1月下旬或2月上旬结束。3)发情期为5月下旬或6月上旬开始，9月上旬结束；2015—2017年发情期时间有延长的趋势。4)产仔期为3月中旬或4月中旬开始，5月下旬或7月下旬结束。5)麋鹿鹿角脱落、群主更替、产仔的年节律存在明显的同步关系，其中鹿角脱落开始时间、鹿角脱落高峰期、鹿角脱落结束时间、第一次发情期开始时间、群主更替高峰期、产仔期开始时间、产仔高峰期、产仔期结束时间与前一年度比较均出现同步提前的现象。6)鹿角脱落年节律存在随着12月平均气温升高而提前的现象；产仔期开始时间和产仔高峰期存在随着前一年9月平均气温的升高而提前的现象。7)鹿角脱落年节律表现出随着年降雨量的增多而提前的现象；第一次发情期开始时间、群主更替高峰期的年节律表现出随着前一年度年降雨量的增多而提前的现象。8)麋鹿鹿角脱落、群主更替、产仔的年节律均不存在随着种群密度升高或降低而提前或延迟的现象。麋鹿繁殖特征的年节律是一个复杂的过程，受气候、营养、种群密度、纬度等环境因子的影响。

Circannual rhythms in antler casting, harem master alternation, calves birth of Pére David's deer (Elaphurus davidianus) and their environmental influencing factors

In order to study the circannual rhythm of reproductive characteristics in Pére David''s deer (Elaphurus davidianus) and its adaptability to the environment, the casted antler were collected during three annual winters (from December to February) of 2014 to 2016 in Beijing Milu Ecological Research Center (BMERC), Beijing, China. Then harem masters were observed and recorded during the rut time (from May to September) of 2015 to 2017. Offspring date of birth during the offspring period (from March to July) from 2016 to 2018 were also recorded. Combined with the environmental factors from 2014 to 2018 such as annual mean temperature, seasonal mean temperature, monthly mean temperature, annual precipitation, start and end of rainy season, and population density, we studied circannual rhythms in antler casting, harem master alternation, calves birth of Pére David''s deer and their environmental influencing factors. The results showed that: (1) there were annual differences in the circannual rhythms antler casting, harem master alternation, calves birth of Pére David''s deer. (2) Antler casting date started in December, ended in late January or early February. (3) There was a second estrus period in Pére David''s deer population. The estrus period started in late May or early June, and ended in early September. The estrus duration from 2015 to 2017 were 91d, 102d, and 110d respectively, which had a tendency to prolong. (4) The offspring period started in mid-March or mid-April, and ended in late May or late July. (5) There was synchronization relationship among circannual rhythms in antler casting, harem master alternation, calves birth. Antler casting start date, median antler casting date, antler casting end date, rut start date, rut median date, offspring start date, median calving date and offspring end date were synchronization advanced than last year respectively. (6) The circannual rhythms in harem master alternation did not show the phenomenon of advance or delay with the increase or decrease of the annual mean temperature, season mean temperature or monthly mean temperature, while circannual rhythms in antler casting increased with the mean temperature in December, and offspring start date, median calving date increased with the mean temperature in September of the previous year. (7) The circannual rhythm in calves birth did not show a corresponding synchronous change with the precipitation factors. While circannual rhythms in antler casting showed advancement with the increase of annual precipitation. Rut start date and rut median date appeared to advance with the increase of annual precipitation in the previous year. (8) There was no synchronization advanced or delayed of circannual rhythms in antler casting, harem master alternation, calves birth as the population when the density increased or decreased. The circannual rhythm of the reproductive characteristics of Pére David''s deer was a complex process, affected by the environmental factors such as climate, nutrition, population density, and latitude.