Impact of twenty‐first century climate change on diadromous fish spread over Europe, North Africa and the Middle East

Abstract

Climate change is expected to drive species ranges towards the poles and to have a strong influence on species distributions. In this study, we focused on diadromous species that are of economical and ecological importance in the whole of Europe. We investigated the potential distribution of all diadromous fish regularly encountered in Europe, North Africa and the Middle East (28 species) under conditions predicted for twenty-first century climate change. To do so, we investigated the 1900 distribution of each species in 196 basins spread across all of Europe, North Africa and the Middle East. Four levels were used to semiquantitatively describe the abundance of species, that is missing, rare, common and abundant. We then selected five variables describing the prevailing climate in the basins, the physical nature of the basins and reflecting historical events known to have affected freshwater fish distribution. Logistic regressions with a four-level ordinal response variable were used to develop species-specific models. These predictive models related the observed distribution of these species in 1900 to the most explanatory combination of variables. Finally, we selected the A2 SRES scenario and the HadCM3 (Hadley Centre Coupled Model version 3) global climate model (GCM) to obtain climate variables (temperature and precipitation) at the end of this century. We used these 2100 variables in our models and obtained maps of climatically suitable and unsuitable basins, percentages of contraction or expansion for each species. Twenty-two models were successfully built, that is there were five species for which no model could be established because their distribution range was too narrow and the Acipenser sturio model failed during calibration. All the models selected temperature or/and precipitation as explanatory variables. Responses to climate change were species-specific but could be classified into three categories: little or no change in the distribution (five species), expansion of the distribution range (three species gaining suitable basins mainly northward) and contraction of the distribution (14 species losing suitable basins). Shifting ranges were in accordance with those found in other studies and underlined the high sensitivity of diadromous fish to modifications in their environment.

Refugia of marine fish in the northeast Atlantic during the last glacial maximum: concordant assessment from archaeozoology and palaeotemperature reconstructions

“…Other studies present evidence of rapid range shifts on the order of several thousand kilometers over a few years for such pelagic species as sardines and anchovies, due to their nonterritorial behaviour and higher dispersal capabilities (McFarlane et al, 2000;Beare et al, 2004). Predictions of future temperature increases have been used to predict the extinction of migratory species from the southern parts of their ranges (e.g., Lassalle and Rochard, 2009), but the calibration of these models depends on how species responded to climatic temperature perturbations in the past. The results presented here capture the southern displacement of certain marine species during the LGM.…”

“…Hence, there is still a crucial gap in the understanding of the influence of oceanic conditions that governed the spatial distribution of the marine species during the LGM. The issue is important because future climate warming scenarios predict that the spatial ranges of important species are expected to shift northward (e.g., Perry et al, 2005) and important amphihaline species, like salmon, are predicted to become extinct in the southern parts of their range (Lassalle and Rochard, 2009).…”

Plasticity of European flounder life history patterns discloses alternatives to catadromy

“…For flounder, the interactive effects of temperature, food availability and substrate type are important factors driving life history patterns (Lassalle & Rochard 2009, Camp et al 2011. However, salinity and dissolved oxygen might not be the most important environmental cues since flounder is a euryhaline species (Summers 1979, Nissling et al 2002, Freitas et al 2009), even able to tolerate hypoxic conditions without compromising osmoregulation (Lundgreen et al 2008).…”

Waning habitats due to climate change: the effects of changes in streamflow and temperature at the rear edge of the distribution of a cold-water fish

“…In a study of the major basins of Europe, Lassalle and Rochard (2009) predicted that the brown trout would "lose all its suitable basins in the southern part of its distribution area ([the] Black Sea, the Mediterranean, the Iberian Peninsula and the South of France), but [would] likely to continue being abundant in [the] northern basins". Almodóvar et al (2011) estimated that the brown trout will be eradicated over almost the entire stream length of the studied basins in northern Spain, and Filipe et al (2013) estimated an expected loss of 57 % of the studied reaches in the Ebro Basin in north-eastern Spain.…”