Long-term monitoring of stream fish at Baixo Sabor LTsER site

Country: Portugal
eLTER site: Baixo Sabor LTER

The Baixo Sabor LTsER is located in Portugal, in the region of Trás-os-Montes, within the watershed of the Sabor river (3868 km2), which drains into the Douro river. It encompasses the lower reaches of the Sabor River and the catchment of its tributaries (1590 km2).
The research on site aims to understand the long-term consequences of river damming on freshwater and adjacent terrestrial ecosystems. As such, a thorough fish monitoring program has been established by CIBIO-InBIO, which started in 2012 with a large-scale survey to set the baseline for assessing future trends.

184 sampling sites were visited, from which we selected 30 representing the main ecological gradients in the basin, sampled through electrofishing since then. 2021 marks 10 years of continuous fish monitoring in Sabor, when, besides the regular monitoring, we intend to repeat the more comprehensive survey carried out in 2012.
This is a very consistent data set, with sampling performed by the same research team, ensuring consistency in effort and methods at each sampling site over the years. Using this dataset we have been able to show how the distribution of species changes in time and space, with important data collected for Iberian endemisms and threatened species.

While sampling fish we have also been able to track the progressive invasion of the watershed by two invasive crayfish. This information has already been used to produce three scientific papers, and the dataset on fish occurrences (2012-2020) is already available in DEIMS. Two of the papers modelled the distribution of crayfish (Filipe et al, 2017) and fish (Ferreira et al, 2016), while the other provides a detailed account of temporal changes (Mota-Ferreira et al, 2021). In particular, this last paper, models how temporal variability patterns change across the watershed, showing faster community changes in streams draining directly to the reservoir, possibly due to invasion by exotic species.
Photo: Mário Mota-Ferreira, Maçãs River 2013
Further reading:
Ferreira, M., Filipe, A. F., Bardos, D. C., Magalhães, M. F., & Beja, P. (2016). Modeling stream fish distributions using interval‐censored detection times. Ecology and Evolution, 6(15), 5530–5541. https://doi.org/10.1002/ece3.2295
Filipe, A. F., Quaglietta, L., Ferreira, M., Magalhães, M. F., & Beja, P. (2017). Geostatistical distribution modelling of two invasive crayfish across dendritic stream networks. Biological Invasions, 19(10), 2899–2912. https://doi.org/10.1007/s10530-017-1492-3

Mota-Ferreira, M., Filipe, A. F., Filomena Magalhães, M., Carona, S., & Beja, P. (2021). Spatial modelling of temporal dynamics in stream fish communities under anthropogenic change. Diversity and Distributions, 27(2), 313–326. https://doi.org/10.1111/ddi.13189