The use of dead stand trees by birds: a prospective study in a Brazilian hydroelectric dam

Abstract: Hydropower constructions cause severe disturbances to biodiversity. Arboreal plants die after flooding; however, they expose their emerged branches (also called paliteiros) as a new habitat for animals and plants. Nothing is known about how paliteiros influence the presence of aquatic birds. This study verified which species of birds use the paliteiros, what are their behaviors and probably consequences to ecological processes. In November 2018, we sampled 5 km of paliteiros recording perched birds and their behaviors in the Três Marias dam, a 1040 km2 flooded area in southeastern Brazil. In total, 5.4% of paliteiros were used by 14 bird species. The Neotropic Cormorant Nannopterum brasilianus (Gmelin, 1789) was the most frequent species. Birds mainly preened feathers; they also rested (with no apparent activity), defecated, hunted, fed, vocalized and drank water. Attention must be focused to some behaviors such as resting and defecation, which may influence long-term ecological processes (e.g., incorporating additional organic matter and changing aquatic community) in the dam.

摘要：水利工程建设会对生物多样性造成严重干扰。被洪水淹没的木本植物会死亡，但其露出水面的枝条（paliteiros）会成为动植物新的栖息生境。目前尚不明确paliteiros会如何影响水鸟的栖息与分布。本研究旨在明确利用paliteiros的鸟类物种、鸟类的栖息行为，以及该生境可能对生态过程产生的影响。2018年11月，我们在巴西东南部面积达1040平方千米的特雷斯马里亚斯大坝（Três Marias dam）库区，对5千米长的paliteiros开展了采样调查，记录了停歇于此的鸟类及其行为。总计有5.4%的paliteiros被14种鸟类利用，其中新热带鸬鹚（Neotropic Cormorant，学名Nannopterum brasilianus，Gmelin, 1789）为最常见的物种。鸟类的主要行为为理羽；此外还包括休憩（无明显活动）、排便、捕猎、取食、鸣叫与饮水。需重点关注休憩与排便等行为，它们可能会对大坝库区的长期生态过程产生影响，例如输入额外有机物质、改变水生群落结构。