Can tortoises facilitate the germination of plants with dry fruits? A simulation of the effects of Chelonoidis carbonarius (Testudines: Testudinidae) on the germination of Leucaena leucocephala (Fabaceae)

Abstract Ingestion of seeds by vertebrates may influence seed germination and dispersion. However the mechanisms responsible by these effects and the importance of turtles in these interactions are still poorly understood. This study aims to evaluate how Chelonoidis carbonarius influences the germination process of Leucaena leucocephala using an experiment conducted at the Federal University of Ceará, Fortaleza-CE, Brazil, that simulates the passage of the seeds of this plant through the digestive tract of C. carbonarius: stomach acidic condition and seeds sown in feces. We demonstrated that sowing the seeds in feces of Chelonoidis carbonarius has a negative effect on the germination of Leucaena leucocephala, decreasing the germination speed index of the seeds, while the acidic conditions have a neutral one. This study is a first attempt to understand how turtles and tortoises may influence the seed germination, and the implications of these findings in natural environments deserve further investigations.

摘要
脊椎动物摄食种子可能对种子萌发与扩散产生影响。然而，介导此类效应的作用机制，以及龟类在这类种间互作中的重要性，目前仍未得到充分阐释。本研究依托巴西塞阿拉州福塔莱萨的塞阿拉联邦大学开展实验，通过模拟银合欢（Leucaena leucocephala）种子通过红腿陆龟（Chelonoidis carbonarius）消化道的两个关键过程——胃部酸性环境处理与粪便基质播种，探究红腿陆龟对该植物种子萌发过程的影响。研究结果显示，在红腿陆龟粪便中播种会抑制银合欢种子萌发，降低其萌发速率指数；而胃部酸性环境处理对种子萌发则无显著影响。本研究是首次探索龟类与陆龟对种子萌发影响的尝试，相关研究结果在自然环境中的生态学意义仍有待进一步研究。