Spatial and seasonal variability of emergent aquatic insects and nearshore spiders in a subtropical estuary.

Variability in the density and distribution of adult aquatic insects is an important factor mediating aquatic-to-terrestrial nutritional subsidies in freshwater ecosystems, yet less is understood about insect-facilitated subsidy dynamics in estuaries. We surveyed emergent (i.e. adult) aquatic insects and nearshore orb-weaving spiders of the families Tetragnathidae and Araneidae in a subtropical estuary of Florida (USA). Emergent insect community composition varied seasonally and spatially; densities were lower at high- than low-salinity sites. At high-salinity sites, emergent insects exhibited lower dispersal ability and a higher prevalence of univoltinism than low- and mid-salinity assemblages. Orb-weaving spider density most strongly tracked emergent insect density rates at low- and mid-salinity sites. Tetragnatha body condition was 96% higher at high-salinity sites than at low-salinity sites. Our findings contribute to our understanding of aquatic insect communities in estuarine ecosystems and indicate that aquatic insects may provide important nutritional subsidies to riparian consumers despite their depressed abundance and diversity compared with freshwater ecosystems. We investigated aquatic-to-terrestrial fluxes of emergent aquatic insects and shoreline orb-weaving spiders in a subtropical Florida estuary. Densities, community composition and functional traits of emergent insects varied seasonally and across low- to high-salinity sites. Spider densities were linked to emergent insect density at low- and mid-salinity sites, but this relationship was decoupled at high-salinity sites. Our findings contribute to our understanding of aquatic insect communities in estuarine ecosystems. [ABSTRACT FROM AUTHOR]

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