Conenna Irene, López-Baucells Adrià, Rocha Ricardo, Ripperger Simon, Cabeza Mar
1Global Change and Conservation Faculty of Biological and Environmental Sciences, University of Helsinki, PO Box 65, Viikinkaari 1, 00014 Helsinki, Finland.
2Helsinki Institute of Sustainability Science, University of Helsinki, Helsinki, Finland.
Mov Ecol. 2019 Aug 16;7:27. doi: 10.1186/s40462-019-0170-8. eCollection 2019.
Bats are among the most successful desert mammals. Yet, our understanding of their spatio-temporal dynamics in habitat use associated with the seasonal oscillation of resources is still limited. In this study, we have employed state-of-the-art lightweight GPS loggers to track the yellow-winged bat in a desert in northern Kenya to investigate how seasonality in a desert affects the a) spatial and b) temporal dimensions of movements in a low-mobility bat.
Bats were tracked during April-May 2017 (rainy season) and January-February 2018 (dry season) using 1-g GPS loggers. Spatial and temporal dimensions of movements were quantified, respectively, as the home range and nightly activity patterns. We tested for differences between seasons to assess responses to seasonal drought. In addition, we quantified home range overlap between neighbouring individuals to investigate whether tracking data will be in accordance with previous reports on territoriality and social monogamy in .
We obtained data for 22 bats, 13 during the rainy and 9 during the dry season. Home ranges averaged 5.46 ± 11.04 ha and bats travelled a minimum distance of 99.69 ± 123.42 m/hour. During the dry season, home ranges were larger than in the rainy season, and bats exhibited high activity during most of the night. No apparent association with free water was identified during the dry season. The observed spatial organisation of home ranges supports previous observations that partitions the space into territories throughout the year.
Our results suggest that, in low-mobility bats, a potential way to cope with seasonally harsh conditions and resource scarcity in deserts is to cover larger areas and increase time active, suggesting lower cost-efficiency of the foraging activity. Climate change may pose additional pressures on and other low-mobility species by further reducing food abundances.
蝙蝠是最成功的沙漠哺乳动物之一。然而，我们对其与资源季节性波动相关的栖息地利用时空动态的理解仍然有限。在本研究中，我们使用了最先进的轻型GPS记录仪，在肯尼亚北部的一片沙漠中追踪黄翅蝠，以研究沙漠中的季节性如何影响a）低移动性蝙蝠运动的空间维度和b）时间维度。
在2017年4月至5月（雨季）和2018年1月至2月（旱季）期间，使用1克重的GPS记录仪追踪蝙蝠。运动的空间和时间维度分别被量化为家域和夜间活动模式。我们测试了季节之间的差异，以评估对季节性干旱的反应。此外，我们量化了相邻个体之间的家域重叠，以调查追踪数据是否与之前关于其领地性和社会一夫一妻制的报告一致。
我们获得了22只蝙蝠的数据，其中13只在雨季，9只在旱季。家域平均为5.46±11.04公顷，蝙蝠每小时移动的最小距离为99.69±123.42米。在旱季，家域比雨季大，蝙蝠在夜间大部分时间表现出高活动水平。在旱季未发现与自由水有明显关联。观察到的家域空间组织支持了之前的观察结果，即全年将空间划分为领地。
我们的结果表明，在低移动性蝙蝠中，应对沙漠中季节性恶劣条件和资源稀缺的一种潜在方式是覆盖更大的区域并增加活动时间，这表明觅食活动的成本效益较低。气候变化可能通过进一步减少食物丰度对其和其他低移动性物种施加额外压力。
