Phenology of brown bear breeding season and related geographical cues
Phenology of brown bear breeding season and related geographical cues
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DOI：
10.1080/24750263.2020.1801866
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发表时间：
2020-01-01
影响因子：
1.8
通讯作者：
Selva, N.
中科院分区：
文献类型：
--
作者：
Garcia-Rodriguez, A.;Rigg, R.;Selva, N.
繁殖生物学的知识往往是不完整的物种复杂的生殖策略。棕熊北极熊是一种一夫多妻的季节性繁殖动物，栖息在各种各样的栖息地和环境条件下。我们收集了36个研究区域的棕熊繁殖季节的信息，这些区域分布在古北和新北地区，并调查了它们的繁殖物候与地理因素（纬度、光周期、海拔和地区）的关系。棕熊交配观察了8个月，从4月到11月，在5月至7月的高峰。我们发现，在研究地区之间，熊的繁殖季节开始的时间有59天的差异，向北每隔一个纬度，平均延迟2.3天。繁殖季节的开始与光周期和纬度有很强的关系，但与区域（即古北界与新北界）和海拔高度无关。首次观测到熊交配发生在低纬度地区。光周期范围在14和18小时之间的季节开始的大部分研究领域。繁殖季节的持续时间从25到138天不等的研究领域。没有一个调查的因素与繁殖季节的长短有关。我们的研究结果支持相关的光周期的发病繁殖，在其他熊类动物中发现，但不是一个较短的繁殖季节在高纬度地区，在其他哺乳动物中报告的模式。我们的研究结果表明，熊的繁殖行为有明显的季节性，但也有一定程度的可塑性。需要对繁殖行为进行系统的实地观察，以增加我们对决定复杂系统物种交配行为的因素以及这些物种如何适应气候变化的知识。
Knowledge about breeding biology is often incomplete in species with complex reproductive strategies. The brown bearUrsus arctosis a polygamous seasonal breeder inhabiting a wide variety of habitats and environmental conditions. We compiled information about brown bear breeding season dates from 36 study areas across their distribution range in the Palearctic and Nearctic regions and investigated how their breeding phenology relates to geographical factors (latitude, photoperiod, altitude and region). Brown bear matings were observed for 8 months, from April to November, with a peak in May-July. We found a 59-day difference in the onset of bear breeding season among study areas, with an average 2.3 days delay for each degree of latitude northwards. The onset of the breeding season showed a strong relationship with photoperiod and latitude, but not with region (i.e. Palearctic vs Nearctic) and altitude. First observations of bear mating occurred earlier in areas at lower latitudes. Photoperiod ranged between 14 and 18 hours at the beginning of the season for most of the study areas. The duration of the breeding season ranged from 25 to 138 days among study areas. None of the investigated factors was related to the length of the breeding season. Our results support the relevance of photoperiod to the onset of breeding, as found in other ursids, but not a shorter breeding season at higher latitudes, a pattern reported in other mammals. Our findings suggest a marked seasonality of bear reproductive behaviour, but also certain level of plasticity. Systematic field observations of breeding behaviour are needed to increase our knowledge on the factors determining mating behaviour in species with complex systems and how these species may adapt to climate change.