Restoration of degraded freshwater ecosystems has gained considerable attention in the USA over the past decades. However, most projects focus almost entirely on the restoration of physical habitat or specific water quality parameters, while ignoring critical ecological processes related to food web re-establishment. In this study, we investigate the impact of riparian habitat in different stages of restoration on food availability for fish in four streams in Pennsylvania, USA. The riparian buffer habitats ranged from open meadow to mature forest and included new to long-term restoration sites. We quantified abundance and community composition of aquatic macroinvertebrates and riparian arthropods with aerial and ground-dwelling life history strategies. We found that riparian habitat and water temperature exert a strong influence over potential food resources for fish, with the open meadow habitat having highest abundance of terrestrial and aquatic insects, lowest taxa richness, and possible multivoltine aquatic insect life-history. Our results provide insight into the importance of riparian buffer habitat and water temperature on the composition of food availability for fish species of concern such as brook trout. The significant differences emphasize the need to include food web dynamics into riparian habitat restoration design to guide future rehabilitation projects focusing on fish conservation.

We assessed the food resource partitioning of three fish species (Arctic charr, Atlantic salmon and alpine bullhead) living in sympatry in a subarctic river. Fish were sampled monthly during the ice-free season (May–October), and dietary overlap among the species was calculated according to Schoener’s index. In October, the diet overlap among all three species was high (>70%). In contrast, large to modest food resource partitioning occurred among Arctic charr and the other two species from May to September (27–59% overlap), whereas there was a distinct diet overlap between Atlantic salmon and alpine bullhead in May, August and September (>64%), but not in July (53%). Surface prey (terrestrial and emerged aquatic insects), probably caught at the surface, were important for Arctic charr in August and September (24.9 and 46.6%, respectively), whereas the other fish species mainly fed on Apatania stigmatella, Mystrophora intermedia and Ephemerella aurivilli. Alpine bullhead seemed to feed close to the bottom, Atlantic salmon used both the bottom and water of various depths, whereas Arctic charr showed the greatest capacity to forage at the water surface. This vertical segregation may be important for fish assemblages in subarctic rivers, allowing food resource partitioning and coexistence of sympatric species.