滨海湿地退化区鸟类刨坑觅食行为促进植被的恢复

鸟类是滨海湿地生态系统中非常重要的组成部分,也是能够通过自身行为影响非生物环境以及生物过程的生态系统工程师。了解鸟类在滨海湿地生态系统中的生态系统工程效应,对于开展滨海湿地的生态修复具有重要作用。通过野外调查研究由灰鹤（Grus grus）和斑嘴鸭（Anas poecilorhyncha）主导的滨海鸟类的刨坑觅食行为对植被退化区的地形以及土壤环境理化指标的影响,进而促进盐地碱蓬（Suaeda salsa）植被的恢复。结果表明：鸟类在植被退化区的刨坑觅食行为改变了退化区的微地形及土壤环境,使得土壤硬度和土壤盐度显著降低,而土壤含水率和土壤碳氮营养指标则显著高于未经鸟类影响的退化平坦区域;另外,鸟类活动改善的凹坑微地形环境能够显著提高盐地碱蓬的种子保留量、幼苗定植量和成株存活量,有效促进盐地碱蓬在植被退化区域的恢复。通过鸟类改变微地形进而促进植被恢复的启发,提出可以尝试人为模拟改造退化区的微地形环境,以通过人为干预的方式促进滨海湿地退化区的植被恢复,对滨海湿地的生态修复具有重要指导意义。

Foraging-associated hollows of birds facilitate the vegetation resilience in a degraded coastal saltmarsh ecosystem

Birds are a key constituent of the coastal ecosystems. They have been identified as vital ecosystem engineers that modify both the abiotic and biotic factors through their behavior processes. Understanding the ecosystem engineering effect of birds is of importance to undergo restoration based on ecosystem process in coastal vegetation systems. Field surveys were conducted to investigate the effect mechanisms of the foraging-associated hollows of birds on the vegetation resilience in a degraded coastal saltmarsh vegetation ecosystem, in the Yellow River Delta, Northern China. Our results showed that the foraging-associated hollows of birds could play an important role in changing microtopography, improving edaphic environment and promoting vegetation establishment. Compared with the degraded flat microtopography areas without birds influence, the soil hardness and the soil salinity in the foraging-associated hollows of birds are significantly lower, while the soil moisture content, and the soil carbon and nitrogen nutrition content in the foraging-associated hollows of birds are significantly higher. Additionally, the foraging-associated hollows of birds could function as effective traps to improve the seed retention, seedling establishment and plant survival, which could effectively promote the recovery of Suaeda salsa. Our study highlights that foraging-associated engineering processes of birds modifying the microtopography should be considered as an important implication, for using artificial microtopography to increase the potentials of vegetation restoration in degraded coastal saltmarsh ecosystems.