Parracciani Cecilia, Maiorano Luigi, Ciucci Paolo
Department of Biology and Biotechnologies "Charles Darwin" University of Rome La Sapienza Rome Italy.
Ecol Evol. 2024 Oct 7;14(10):e70225. doi: 10.1002/ece3.70225. eCollection 2024 Oct.
Interspecific interactions among species of the same guild play a critical role in shaping their realized niches, and their understanding may disclose mechanisms of coexistence. Investigating interactions among apex predators is of ecological and management interest, especially in human-dominated landscapes where type and intensity of their interspecific competition may be affected by human interference. During 2005-2010, we investigated, by means of GPS-telemetry, interactions between brown bears ( = 19) and wolves ( = 7) in a long-established national park in the central Apennines, Italy, where bears and wolves have always coexisted close to humans. Based on a K-select analysis and a randomization approach, we assessed the extent of overlap between the species' niches on a seasonal basis. Bears and wolves clearly segregated in fall but not during summer when overlap between their realized niches suggests a convergent adaptation to a seasonal peak of anthropogenic pressure. However, using multi-species resource selection functions (RSFs) at the home range level (i.e., third-order selection), we revealed that habitat selection by bears and wolves was reciprocally affected also when their niches overlapped, possibly disclosing mechanisms of fine-scale resource partitioning. In early summer, bears selected areas with a high probability of resource selection by wolves, but in late summer avoided areas positively selected by wolves. On the contrary, wolves avoided areas where the probability of resource selection by bears was high, both in late summer and fall. These results indicate that bears and wolves do interact in our study area and, although the actual behavioral mechanisms are unknown, they reciprocally and asymmetrically affect their realized niche and habitat selection patterns. Further research is needed to better understand how anthropogenic factors impact intraguild interactions and what are the effects at the population and community levels.
同一功能群物种之间的种间相互作用在塑造它们的实际生态位方面起着关键作用，对其的理解可能会揭示共存机制。研究顶级食肉动物之间的相互作用具有生态学和管理意义，尤其是在人类主导的景观中，它们种间竞争的类型和强度可能会受到人类干扰的影响。在2005年至2010年期间，我们通过GPS遥测技术，对意大利亚平宁山脉中部一个历史悠久的国家公园内的棕熊（n = 19）和狼（n = 7）之间的相互作用进行了调查，在该公园中，熊和狼一直与人类近距离共存。基于K选择分析和随机化方法，我们按季节评估了物种生态位之间的重叠程度。熊和狼在秋季明显分离，但在夏季没有，此时它们实际生态位之间的重叠表明它们对人为压力季节性峰值的趋同适应。然而，在栖息地范围水平上使用多物种资源选择函数（RSF）（即三阶选择），我们发现当熊和狼的生态位重叠时，它们的栖息地选择也会相互影响，这可能揭示了精细尺度资源分配的机制。在初夏，熊选择狼有高资源选择概率的区域，但在夏末避开狼积极选择的区域。相反，狼在夏末和秋季都避开熊有高资源选择概率的区域。这些结果表明，在我们的研究区域中熊和狼确实存在相互作用，尽管实际的行为机制尚不清楚，但它们相互且不对称地影响着它们的实际生态位和栖息地选择模式。需要进一步的研究来更好地理解人为因素如何影响功能群内的相互作用以及在种群和群落水平上的影响是什么。
