A century of limnological evolution and interactive threats in the Panama Canal: Long-term assessments from a shallow basin

Abstract

Multi-proxy records reveal the effects of impoundment across a shallow neotropical reservoir basin in the Panama Canal.  Records show that limnological conditions shifted from a swamp-type environment to a lake system.  Despite major human impacts, fluvial hydrology still governs the lake basin ecosystem functioning.  Management of the basin must focus on maintaining long-term river hydrodynamics.

Terrestrial protected areas maintain freshwater ecosystem resilience to costly aquatic invasive species in the Panama Canal

“…Thus, tNPAs are suggested to have a striking positive effect on their adjacent aquatic ecosystems by promoting diversity, increasing community heterogeneity, and potentially enhancing the ecosystem ability to resist the establishment of IAS. While recent simulations predict a positive impact of tNPAs on lowland tropical freshwater ecosystems 12 , our result is surprising because the Gatun Lake is a reservoir with a long history of human impacts and has been heavily invaded 17,18 .…”

“…1c). It has been invaded by a suite of species including a variety of fish (e.g., the peacock bass Cichla ocellaris), mollusc (e.g., the redrimmed melania snail Melanoides (Thiara) tuberculata, and the South American apple snail Pomacea bridgesii), mammals (e.g., the American manatee Trichechus manatus), and macrophytes (e.g., the water thyme Hydrilla verticillata and the water hyacinth Eichhornia crassipes), either accidentally or deliberately 17,18 . Furthermore, since the canal was completed in 1914, it came under the protection of the US government and extensive forest areas were safeguarded in the northern half of the lake by the creation of a nature reserve in Barro Colorado Island (BCI) in 1923 19 .…”

“…1c) to explore the role of tNPAs and the resilience of the aquatic ecosystems. To achieve this, we (1) defined a baseline, pre-dam community and ecosystem conditions, (2) surveyed the macrophyte composition of the tNPAs and other non-tNPAs, and (3) compared the macrophyte communities relative to predam species (for detailed methods see 17 and supplementary material).…”

Natural experiments and long-term monitoring are critical to understand and predict marine host–microbe ecology and evolution

“…For example, melting of ice is opening new pathways for the movement of animals, plants, and microbes through the Arctic, from the North Pacific to the North Atlantic, leading to one of the largest species invasions ever observed [ 83 ]. The gradual increase in salinity caused by the expansion of the Panama Canal, along with predicted increased runoff and evaporation, will likely result in greater movement of marine species between the tropical Western Atlantic and the TEP [ 84 ] ( Fig 4 ). Construction of the Suez Canal in 1869 caused an influx of saline water into the Mediterranean that was followed by the intrusion of invasive species from the subtropical Red Sea [ 85 ].…”

River connectivity and climate behind the long‐term evolution of tropical American floodplain lakes

“…However, natural hydrological dynamics of tropical floodplains can be affected by long-term (decades-centuries) human-derived modifications such as river damming, deforestation, land-use change, and climate change (Angarita et al, 2018;Salgado et al, 2020;Van Looy et al, 2019).…”