River logjams cause frequent large-scale forest die-off events in Southwestern Amazonia

Umberto Lombardo
2017 Earth System Dynamics Discussions  
This paper investigates the dynamics of logjam-induced floods and alluvium deposition in the Bolivian Amazon and the effects these have on forest disturbance/recovery cycles. It expands on previous work by Gullison et al (1996) who reported a case of catastrophic floods triggered by logjams in the Chimane Forest on the Bolivian Amazon. No further studies have followed up on this observation and no research has been published on the effects of large wood in tropical lowland rivers. The study is
more » ... ased on the analysis of a time series of Landsat imagery (1984–2016) and field evidence. Results show that logjam-induced floods are a major driver of forest disturbance along the Andean piedmont in the Bolivian Amazon. Logjams form on an almost yearly basis and migrate upriver until an avulsion takes place. Logjam-induced floods are here characterized by a sudden deposition of a thick sand layer and the death of forest in a V-shaped area. The Bolivian Amazon offers a unique opportunity to further research on how large wood affects river behavior in lowland tropical settings and how large and frequent forest disturbance events resulting from river logjams affect forest biodiversity and community successions.
doi:10.5194/esd-2017-19 fatcat:2canp3wirnaodanvo7b42rhgqu