物种适应季节变化的能力对于种群的长期生存至关重要。换毛是哺乳动物适应环境季节性变化的关键生活史事件，主要受到光周期的调控，但由于气候变化的影响，稳定的光周期与变化的温度之间的差异可能导致换毛物候与季节事件的不匹配，从而影响种群的生存。因此，评估物种换毛物候的可塑性，了解物种对于气候变化的适应能力，对于开展物种保护工作至关重要。梅花鹿(Cervus nippon)在东北亚森林生态系统功能和服务中起重要作用，但对野生梅花鹿换毛物候的研究相对较少。本研究使用2019 - 2022年的红外相机监测数据，评价了东北虎豹国家公园梅花鹿换毛的生物学特征和时间规律，并分析了性别对换毛物候的影响。此外，在研究区域内选择了具有温度差异的北部区域和南部区域，通过比较两区域内梅花鹿的换毛时间，探究了环境温度对换毛时间的影响。主要的研究结果如下：

(1) 2019 - 2022年，红外相机陷阱共拍摄到33,926条梅花鹿视频，经筛选后得到有效换毛事件4,904次，其中春季2,307次，秋季2,597次。

(2) 梅花鹿每年换两次毛，夏毛和冬毛在形态结构上具有很大差异。春季换毛的平均开始时间在5月上旬，个体换毛的持续时间为20 - 26天；梅花鹿种群完成春季换毛需要38 - 48天，到6月中旬种群中所有个体已完成换毛。秋季换毛的平均开始时间在8月末到9月初，部分雄性在8月中旬时开始秋季换毛，个体换毛的持续时间为12 - 18天；梅花鹿种群完成秋季换毛需要49 - 58天，到10月上旬种群中所有个体已完成换毛。

(3) 在春季，雌性梅花鹿的换毛开始时间与雄性基本一致，但换毛持续时间比雄性长6 - 8天；在秋季，雌性梅花鹿的换毛开始时间比雄性晚8 - 13天，换毛持续时间在部分年份比雄性更长。

(4) 相比于温度较高的南部区域，在温度较低的北部区域，梅花鹿春季换毛的持续时间缩短3天，秋季换毛提前3天开始，持续时间延长5天。

研究结果表明，梅花鹿的换毛时间在性别上存在差异。梅花鹿的换毛物候具有一定的可塑性，梅花鹿可以根据温度的变化调整换毛时间，以维持与季节变化的同步。本研究建议对梅花鹿种群进行长期观测，全方位地评估野生种群对于气候变化的适应能力，为该物种的保护和管理提供科学依据。

The ability of species to adapt to changes in seasonality is essential for long-term survival of populations. Moult is a key life-history event for mammals to adapt to seasonal changes of environment, primarily regulated by photoperiod. However, due to the influence of climate change, disparity between stable photoperiod and fluctuating temperatures may lead to mismatches between moult phenology and seasonal events, thereby affecting population survival. Therefore, assessing the plasticity of species' moult phenology and understanding their adaptive capacity to climate change are crucial for species conservation efforts. Sika deer (Cervus nippon) play an important role in the functioning and services of the forest ecosystems in Northeast Asia, but there has been relatively little research on the moult phenology of wild sika deer. This study utilized camera traps monitoring data from 2019 to 2022 to evaluate the biological characteristics and temporal patterns of moult in sika deer within the Northeast China Tiger and Leopard National Park and analyzed the influence of gender on moult phenology. Additionally, within the study area, we selected northern and southern areas with temperature variations. By comparing the moult time of sika deer in these two areas, we explored the impact of environmental temperature on moult time. The main results of study are as follows:

(1) From 2019 to 2022, a total of 33,926 videos of sika deer were captured by the camera traps. After screening, 4,904 valid moult events were identified, with 2,307 occurrences in spring and 2,597 in autumn.

(2) Sika deer moult twice a year, with significant differences in the morphology between summer coats and winter coats. The mean start day of spring moult is early May, and the duration of moult for individuals ranges from 20 to 26 days. The population of sika deer completes spring moult within 38 - 48 days, with all individuals in the population typically completing spring moult by mid-June. The mean start day of autumn moult is late August to early September, with some males starting as early as mid-August. The duration of autumn moult for individuals ranges from 12 to 18 days. The population of sika deer completes autumn moult within 49 - 58 days, with all individuals in the population typically completing autumn moult by early October.

(3) In spring, the start day of moult for female sika deer is generally similar to that of males, but the moult duration is 6 to 8 days longer than males. In autumn, the start day of moult for females is delayed by 8 to 13 days compared to males, and in some years, the moult duration is longer for females than males.

(4) Compared to the warmer southern regions, in the cooler northern areas, sika deer experience a reduction of 3 days in the duration of spring moult, while autumn moult starts 3 days earlier and lasts 5 days longer.

The results indicate that there are gender differences in the moult time of sika deer. The moult phenology of sika deer exhibits a certain degree of plasticity, as they can adjust their moult time according to temperature changes to maintain synchrony with seasonal changes. This study suggests conducting long-term observations on sika deer populations to comprehensively assess their adaptability to climate change and provide scientific grounds for the management of conservation areas.