赤水桫椤自然保护区小灵猫及其潜在啮齿类猎物活动节律的季节适应格局

Seasonal variation patterns of daily activity rhythm of small Indian civets(Viverricula indica)and their potential rodent prey in Guizhou Chishui Alsophila National Nature Reserve,China

动物的日活动节律具有内源性且受外界生态因素(光周期、气候和食物等)影响,是动物生态适应性特征之一。阐明活动节律与气候和捕食者−猎物的关系,对于理解动物的生存策略、指导保护等至关重要。目前通过红外相机技术探究野生动物日活动节律日益受到学者们的关注。灵猫科动物是热带和亚热带生境中的重要次级消费者之一,但其野外相关研究甚少。本研究基于2016年12月至2022年7月在贵州赤水桫椤国家级自然保护区及其周边区域设置的60个红外相机位点监测影像资料,筛选小灵猫(Viverricula indica)及其相应监测位点的潜在啮齿类猎物数据。通过核密度函数比较分析了保护区内、外的小灵猫及其潜在啮齿类猎物在雨季、旱季的日活动节律特征。结果显示,小灵猫有明显的晨昏两个活动高峰,时间分别是03:00—06:00和19:00—24:00。季节比对发现,小灵猫雨季凌晨活动高峰(03:00—05:00)早于旱季(04:00—06:00),活动强度较旱季高且集中;黄昏后的活动较旱季有所延长。进一步分析其活动与潜在的啮齿类猎物的重叠度,结果发现小灵猫与赤腹松鼠(Callosciurus erythraeus)的重叠度整体较低(雨季,Δ=0.18;旱季,Δ=0.16);与夜行性鼠类的活动节律重叠度高达90%以上,其中旱季的重叠系数(Δ=0.93)高于雨季(Δ=0.90)。此外,在保护区内的小灵猫凌晨活动高峰结束较保护区外延迟约1 h;黄昏后高峰阶段的活动强度(核密度)峰值明显高于保护区外。少许日间活动也主要出现在保护区内。上述结果表明,小灵猫的昼夜节律既有保守性,也具有一定的季节可塑性。这些特征型表现与季节性猎物分布和环境变化关联,并受人类活动的影响。本研究结果对充分认识小灵猫生活史特征以及实现物种有效保护提供数据支持。

The daily activity rhythm of animals is an adaptive response with endogenous characteristics to environmental constraints(e.g.photoperiod,climate),food availability,and predation risk.Elucidating the driving factors of daily activity rhythms is crucial in understanding wildlife fitness and guiding conservation.Currently,more and more researchers are paying attention to the use of infrared camera technology to explore the daily activity rhythms of wild animals.This study was based on the monitoring data from 60 infrared-triggered cameras in three sample plots(two in the reserve and one outside the reserve)using continuous 1 km×1 km grids throughout the year in Guizhou Chishui Alsophila Reserve and its surrounding areas from December 2016 to July 2022.We selected the data of small Indian civets(Viverricula indica)and their potential rodent prey monitored in the corresponding sites of civets.We compared the daily activity rhythm characteristics of small Indian civets and their potential rodent prey by employing a kernel density estimation and using overlap coefficient to quantify the temporal overlap between the inside and outside of the reserve across wet and dry seasons.Our results showed that small Indian civets had two distinct peaks of activity:one in the early morning from 03:00–06:00 and the other in the evening from 19:00–24:00.When comparing the two seasons,we found small Indian civets had an earlier morning activity peak in the wet season(03:00–05:00)than that in the dry season(04:00–06:00),with higher and more concentrated morning activity intensity in the wet season;but with an extended activity after dusk in the wet season.The overlap analysis between the activity of small Indian civets and their potential rodent prey revealed a higher overlap coefficient(over 90%)with nocturnal rodents.There were higher overlap coefficients in the dry season(Δ=0.93)than in the rainy season(Δ=0.90),but not with Pallas squirrels(Callosciurus erythraeus)(wet season,Δ=0.18;dry season,Δ=0.16).The peak of the early morning activity of the small Indian civet ended about one hour later in the reserve sites than outside the reserve.Additionally,some daytime activity mainly occurred in the areas inside the reserve.Therefore,our results suggest that the daily activity rhythm of the small Indian civet is both conservative and seasonally plastic.These were affected by the seasonal distribution of prey and environmental changes but also affected by human activity.Our study contributes to a better understanding of small Indian civets’life history characteristics and their effective conservation.