| 丁慧芳,陈青,王亚芳,朱仔伟,周海燕,王文娟.2024.鄱阳湖围垦区藕塘生境小天鹅与白鹤的种间关系.动物学杂志,59(2):161-171. |
| 鄱阳湖围垦区藕塘生境小天鹅与白鹤的种间关系 |
| Interspecific Relationships Between Tundra Swans Cygnus columbianus and Siberian Cranes Leucogeranus leucogeranus in the Lotus Ponds Reclamation Area Around Poyang Lake |
| 投稿时间：2022-08-01 |
| DOI：10.13859/j.cjz.202422191 |
| 中文关键词: 南昌五星白鹤保护小区 人工生境 觅食时间 行为节律 种间竞争 |
| 英文关键词:Nanchang Wuxing Siberian Crane Reserve Agricultural fields Foraging time The rhythms of behavior Interspecific competition |
| 基金项目:中央高校基本科研业务费专项(No. BLX202252，BH2022-06)，国家自然科学基金项目(No. 32160132)； |
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| 中文摘要: |
| 鄱阳湖是小天鹅(Cygnus columbianus)和白鹤(Leucogeranus leucogeranus)极为重要的越冬地，它们均主要以沉水植物苦草(Vallisneria spp.)冬芽为食，且通过觅食空间生态位分化减少种间竞争。近年来，鄱阳湖苦草冬芽锐减导致大量小天鹅和白鹤由自然生境转移到南昌五星白鹤保护小区的藕塘觅食。大量小天鹅和白鹤集中在小片藕塘觅食可能导致种间竞争强度增加。因此，本研究以五星白鹤保护小区藕塘为研究地点，于2021年11月10日至25日，采用瞬时扫描法和焦点动物法调查了藕塘与白鹤混群和不与白鹤混群时小天鹅的日间行为、单次取食时间和每分钟摄食成功频次，并采用单因素方差分析或Mann-Whitney U检验对数据进行统计分析。结果表明，小天鹅日间行为主要以觅食(45.59%)、运动(17.05%)和休息(15.92%)为主。小天鹅和白鹤混群时的觅食行为比例和单次觅食时间显著高于不混群时，表明小天鹅主要通过增加觅食时间以应对种间竞争的负面影响，满足能量需求。小天鹅混群时的每分钟摄食成功频次显著高于不混群时，这可能是由于小天鹅通过摆动脚蹼或者扁平喙啄食的方式较难取食到大块莲藕，而白鹤到达藕田后，通过长喙啄碎藕块后便于小天鹅取食，进而提高了小天鹅的摄食成功率。本研究结果表明，沉水植被退化引起的小天鹅和白鹤的食性改变和觅食空间变化导致了物种之间竞争强度增加，在藕塘觅食的小天鹅通过增加觅食时间的方式应对种间竞争。本研究有助于评估沉水植被退化对小天鹅等珍稀濒危鸟类的潜在影响，为鸟类保护政策的制定提供科学依据。 |
| 英文摘要: |
| [Objectives] Poyang Lake is the largest freshwater lake in China and one of the important wintering grounds for Tundra Swans Cygnus columbianus and Siberian Cranes Leucogeranus leucogeranus. They primarily feed on the tubers of the Vallisneria spp. in Poyang Lake, and reduce interspecific competition through spatial niche differentiation. In recent years, the quality of Poyang Lake wetland ecosystem has been deteriorating due to human activities and frequent flooding. The tubers of Vallisneria have been seriously degraded. A sharp decline of tubers of Vallisneria has led a large number of Tundra Swans and Siberian Cranes to shift their foraging habitats from natural wetlands to lotus ponds of the Nanchang Wuxing Siberian Cranes Reserve. Given the limited food resources in Lotus Ponds, the large numbers of Tundra Swans and Siberian Cranes at small lotus ponds may lead to an increase of interspecific competition, which may have a negative impact on the survival of one or both species. [Methods] In this study, we used the scan-sampling technique and focus animal method to investigate the diurnal behaviors, single feeding time, and foraging success frequency per minute of Tundra Swans in monospecific flocks and mixed-species flocks (i.e., flocks include Tundra Swans and Siberian Cranes) at lotus ponds of the Nanchang Wuxing Siberian Cranes Reserve. The investigations were conducted from November 10 to November 25, 2021. One-way ANOVA test or Mann-Whitney U test was used to analyze the data. [Results] The results indicated that foraging (45.59%), moving (17.05%), and resting (15.92%) were the main behaviors of Tundra Swans (Fig. 1). The peak foraging time of Tundra Swans was from 9:00 to 10:00 in the morning and from 16:00 to 17:00 in the evening, and the trough occurred from 11:00 to 12:00 in the noon (Fig. 2). These behavioral strategies may help Tundra Swans cope with the energy consumption at night. Tundra Swans in mixed-species flocks spent significantly higher proportion of time on foraging (47.62%) than that in monospecific flocks (43.34%) (Fig. 3). The average duration of feeding bouts of Tundra Swans in mixed-species flocks (10.90 ± 4.92 s) was significantly higher than that in monospecific flocks (9.96 ± 6.56 s) (Fig. 4). Interspecific competition might result in decreased food availability and lower foraging efficiency for Tundra Swans, hence Tundra Swans increased foraging time to compensate for the negative effects of interspecific competition and to satisfy the energy requirement. The foraging success frequency of Tundra Swans was significantly higher in mixed-species flocks (0.69 ± 0.55 times/min) than that in the monospecific flocks (0.52 ± 0.56 times/min) (Fig. 4). Tundra Swans can hardly get chunks of lotus root by swinging their flippers or pecking with flat beaks. After Siberian Cranes arrived at the lotus ponds, they pecked the lotus root to pieces with their long beaks, which might facilitate Tundra Swan foraging and hence improving their foraging success. [Conclusion] The results of this study indicate that the degradation of submerged vegetation in Poyang Lake has changed the foraging habitats and foraging space of Tundra Swans and Siberian Cranes. A large number of Tundra Swans and Siberian Cranes are competing for food at the same lotus ponds, and interspecific competition intensifying, which may have a negative impact on their survival. Tundra Swans coped with the negative impacts of interspecific competition by increasing foraging time. Our study contributes to the assessment of the potential impacts of submerged vegetation degradation on endangered birds such as Tundra Swans and provides a scientific basis for the formulation of bird conservation policies. |
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