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同域物种的共存机制研究一直是群落生态学中的重要内容,开展同域物种的比较研究有助于进一步分析种间行为、生态适应与共存机制等[1]。根据生态位理论,同域分布且生态需求相近的物种,需要通过生态位分化才可有效减少或避免有限资源条件下的竞争[2],且必须通过一定的生态位分化才可达到稳定共存[3]。生态位分化往往涉及栖息地利用、食性、行为节律等多个维度[4],尤其对于同域分布的近缘物种上表现得更为明显,由于具有相似的身体结构、行为活动和资源需求等,往往成为潜在的竞争者[5-6]。因此,同域物种要想实现长期共存,往往需要调节各自的栖息地利用模式、食性选择与活动节律以促进生态位分化[7]。
动物的活动节律是行为生态学研究中的重要内容,其中日活动节律是动物应对昼夜更替(包括温度、湿度、光照强度等)长期适应而逐渐形成的在一天中不同时间段下的活动强度和变化规律[8]。目前,关于活动节律在同域物种共存机制中的作用研究已有不少文献报道,包括同域分布的地栖性雉类[4,9-10]、有蹄类[6,11]、食肉类[12,13]、啮齿类[14-15]等方面,研究表明同域分布且生态需求相近的物种可以通过调节活动节律来减少资源竞争从而达到共存。
作为一种新型的野生动物监测技术,红外相机技术自上世纪90年代应用以来,经过近三十年的发展,目前已广泛应用到野生动物生态学与保护学研究中[16-17]。近年来,利用该技术来探究野生动物活动节律和生态位分化的研究已有不少报道,相关应用也证实了该技术可以作为分析同域物种共存机制的有效技术途径[6,9-11,13-15]。
水鹿(Cervus equinus)隶属偶蹄目(Artiodactyla),鹿科(Cervidae),鹿属[18],在我国广泛分布于南部和西南部热带及亚热带地区,包括云南、四川、重庆、青海、贵州、广西、海南、湖南、广东、江西、台湾等地[19],被IUCN濒危物种红色名录列为易危(Vulnerable, VU)等级[20],属于国家二级重点保护野生动物[21]。毛冠鹿(Elaphodus cephalophus)隶属偶蹄目,鹿科,毛冠鹿属[18],广布于我国南部并延伸至缅甸,在我国的分布区包括湖南、浙江、安徽、福建、江西、湖北、广东、广西、四川、贵州、云南、西藏、陕西、甘肃、青海、重庆等地[19],被列为近危(Near Threatened, NT)等级[20],属于国家二级重点保护野生动物[21]。这2种鹿科动物在分布海拔上较为接近,均为植食性,生态位相近[22],很可能成为潜在竞争关系,因此可以作为研究同域分布有蹄类物种生态位分化的理想选择。在以往的研究中,欧善华等从食性角度比较了毛冠鹿和黑麂(Muntiacus crinifrons)的差异[23];孙佳欣等简单描述了同域分布水鹿和毛冠鹿在内的9种有蹄类动物日活动节律模式,但缺乏具体的(如季节间)差异性比较[24];邹启先等分析了麻阳河同域分布毛冠鹿和小麂(Muntiacus reevesi)的时空分布格局[6]。然而,关于同域分布水鹿和毛冠鹿针对性的活动节律比较研究尚未见报道,这2种鹿科动物在活动节律上究竟存在何种分化以实现共存?
为了回答以上问题,本研究于2017年5月—2018年4月,在四川贡嘎山国家级自然保护区内布设160个红外相机监测位点,利用红外相机数据来探究这2种鹿科动物在活动节律上的分化程度,以期为同域分布下近缘物种的共存机制研究和针对性保护管理策略的制定提供重要的数据参考。
Comparison Study on Activity Rhythms of Sambar (Cervus equinus) and Tufted Deer (Elaphodus cephalophus) in the Same Region Based on Infrared Camera Data
doi: 10.12172/202108030001
- Received Date: 2021-08-03
- Available Online: 2022-03-11
- Publish Date: 2022-04-26
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Key words:
- Cervus equinus /
- Elaphodus cephalophus /
- Gongga Mountain National Nature Reserve /
- Infrared camera traps /
- Daily activity pattern /
- Kernel density estimation /
- Coefficient of overlap /
- Temporal niche differentiation
Abstract: The comparative study of sympatric species is helpful for further analysis of interspecies behavior, ecological adaptation and co-existence mechanism. In order to explore the differences in daily activity pattern, temporal niche differentiation and coexisting mechanism of sympatric species, infrared camera were used to continuously monitor Sambar (Cervus equinus) and Tufted Deer (Elaphodus cephalophus) from May 2017 to April 2018 in Gongga Mountain National Nature Reserve, Sichuan province. The kernel density estimation and coefficient of overlap were used to analyze the daily activity rhythm of the two species. The results showed that both Sambar (Cervus equinus) and Tufted Deer (Elaphodus cephalophus) were more inclined to the morning and dusk activity, but the similarity of the daily activity rhythm between the two was lower (Δ=0.80, P<0.01). There were three activity peaks in the daily activity rhythm of Sambar, which were 03:30—04:00, 06:00—08:00 and 18:00—23:30, while there were only two activity peaks in the daily activity rhythm of Tufted Deer, which were 07:00—12:00 and 17:00—21:30. The morning activity peak of Sambar was significantly earlier than that of Tufted Deer, while the end time of dusk activity peak was 2 hours later. The daily activity rhythm of the two species was significantly different between seasons (Sambar: Δ=0.93, P=0.03; Tufted Deer: Δ=0.88, P<0.01). The morning activity peak of the two species appeared half an hour later in the dry season than that in the rainy season, while the dusk activity peak (19:00) of Tufted Deer was one hour earlier than that in the rainy season (20:00). Compared with the rainy season, the dusk activity peak values of both were larger and the activity peaks of both were longer in the dry season than that in the rainy season, however, in the rainy season, the activity peak values and activity peaks of the two species showed opposite trend. The overlap index of the daily activity rhythm between Sambar and Tufted Deer during the research period was lower (Δ=0.80), and the overlap index (Δ=0.83) and the maximum activity peak value (0.12) in the dry season were higher than those in the rainy season (Δ=0.74; the peak value was 0.10), but there were significant differences between the whole and the seasons (P<0.01). This study showed that sympatric species of Sambar and Tufted Deer could coexist through temporal niche differentiation to reduce competition for food, space and time resources. The results of this study can provide important data reference for further research on the co-existence mechanism of sympatric species and for the formulation of targeted conservation and management strategies.