Presentation Title

Georgia Coastal Plain Rivers: Leaf Litter Processing and Macroinvertebrate Assemblages

Location

Nessmith-Lane Atrium

Session Format

Poster Presentation

Research Area Topic:

Natural & Physical Sciences - Biology

Abstract

Leaf litter processing is an ecosystem-level process, connecting terrestrial vegetation, microbes, invertebrates, and physicochemical stream properties and is a fundamental component of the trophic dynamics of freshwater ecosystems. When combined with structural assessments (e.g., water chemistry and community structure), measures of leaf litter breakdown may serve as an indicator of overall system health. Leaf litter processing rates and the concomitant macroinvertebrate assemblages were studied in main-channel habitats of three Coastal Plain rivers in Southeast Georgia: Altamaha, Ogeechee, and Savannah. Study sites were chosen to assess the effects of flow regime, particularly the magnitude of discharge, on leaf litter breakdown and assemblage structure. Ninety-six single-species packs of water oak leaves were deployed in mid-September 2014 and retrieved at two-week intervals over an eight-week period. During the study period, a distinct gradient in discharge was observed (average Q = 150.8, 75.3, and 8.2 m3/s on the Savannah, Altamaha, and Ogeechee, respectively). Among basins, mean leaf litter processing coefficients (k) ranged from slow to medium (range: -0.0077 to -0.0129) with an average of 596 days to 95% loss. Overall, assemblage structure was similar between basins. Chironomidae was the most abundant taxon in all assemblages, with nearly half (48.2%) of the Ogeechee’s total abundance attributed to midges. In the Altamaha, hydrobiid snails were the second most common taxon (15.4%). Over one quarter (25.6%) of the Savannah’s assemblage was composed of caddisflies, with Hydropsychidae being the dominant family (14.1%).

Presentation Type and Release Option

Presentation (Open Access)

Start Date

4-16-2016 10:45 AM

End Date

4-16-2016 12:00 PM

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Apr 16th, 10:45 AM Apr 16th, 12:00 PM

Georgia Coastal Plain Rivers: Leaf Litter Processing and Macroinvertebrate Assemblages

Nessmith-Lane Atrium

Leaf litter processing is an ecosystem-level process, connecting terrestrial vegetation, microbes, invertebrates, and physicochemical stream properties and is a fundamental component of the trophic dynamics of freshwater ecosystems. When combined with structural assessments (e.g., water chemistry and community structure), measures of leaf litter breakdown may serve as an indicator of overall system health. Leaf litter processing rates and the concomitant macroinvertebrate assemblages were studied in main-channel habitats of three Coastal Plain rivers in Southeast Georgia: Altamaha, Ogeechee, and Savannah. Study sites were chosen to assess the effects of flow regime, particularly the magnitude of discharge, on leaf litter breakdown and assemblage structure. Ninety-six single-species packs of water oak leaves were deployed in mid-September 2014 and retrieved at two-week intervals over an eight-week period. During the study period, a distinct gradient in discharge was observed (average Q = 150.8, 75.3, and 8.2 m3/s on the Savannah, Altamaha, and Ogeechee, respectively). Among basins, mean leaf litter processing coefficients (k) ranged from slow to medium (range: -0.0077 to -0.0129) with an average of 596 days to 95% loss. Overall, assemblage structure was similar between basins. Chironomidae was the most abundant taxon in all assemblages, with nearly half (48.2%) of the Ogeechee’s total abundance attributed to midges. In the Altamaha, hydrobiid snails were the second most common taxon (15.4%). Over one quarter (25.6%) of the Savannah’s assemblage was composed of caddisflies, with Hydropsychidae being the dominant family (14.1%).