Rapid climate change has increased post‐breeding and autumn bird density at the eastern limit of Europe

Habitat preferences of small fish species in rivers at the eastern edge of Europe

We studied the probability of occurrence, distribution and abundance of eight small fish species in 512 small rivers at the eastern edge of Europe in a region of high geographical and environmental heterogeneity. Stone loach, common minnow, and gudgeon were recorded in more than 50% of the study sites. Common minnow was the most abundant species, contributing 66% of all captures. Elevation, depth, and width of the river were the main environmental factors influencing the distribution of more than half of the studied fish species. Our research in the eastern edge of Europe shows that fish preferences in terms of probability of occurrence, abundance, and niche breadth for environmental factors can vary greatly, even among closely related species. depth.

Occurrence, Abundance and Distribution of Bleak, Common Spirlin, and Sunbleak in the Environmental Gradients of Small Rivers (Tatarstan)

The probability of occurrence, distribution, and abundance of bleak, common spirlin, and sunbleak in 316 small rivers of the Republic of Tatarstan were studied. The studied region has a high geographical and environmental heterogeneity. The impact of environmental factors on species occurrence was analyzed with generalized linear models. Among the selected fish, sunbleak had the highest probability of occurrence, and bleak had the highest abundance. Elevation was the only environmental variable significantly affecting the probability of occurrence of all three species. With an increase in elevation, the probability of occurrence of bleak, common spirlin, and sunbleak significantly decreased. Optimum values and niche breadth differed significantly between fish species for some of the environmental variables.