Recent and subfossil diatom assemblages as indicators of environmental change (including fish introduction) in a high-mountain lake

We investigated modern-littoral and subfossil sediment-core diatoms in the shallow (max depth 6.4 m) high-mountain Lake Balma Orsiera Rocciavrè Nature Park (Italian Western Alps). Our study provided evidence that might be related to response of diatom assemblages fish introduction, particular decreasing nutrient-enrichment sensitive low-profile life-form/ecological guild increase species known react positively augmented nutrient availability due excretions (e.g., Fragilaria nanana, Pseudostaurosira brevistriata, Staurosirella neopinnata). are, however, aware some these effects could as well have been caused by pastures cattle watering, increased temperatures global warming, we acknowledge typical complex-interaction pattern among different stressors. High-mountain lakes are ‘‘early warning systems’’ for whole alpine system can contribute valuable information also on interactions between environmental changes anthropogenic impacts. Benthic diatoms, particular, provide useful indications deleterious non-native grazing, thus support an adaptive sustainable management sake nature conservation.