2023 Early Hearing Detection & Intervention Conference

March 5-7, 2023 • Cincinnati, OH

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5/20/2019 | 11:30 AM - 11:45 AM | ENERGY FLOW PATTERNS THROUGH FOOD WEBS IN NEOTROPICAL HEADWATER STREAMS OF THE BRAZILIAN SAVANNA | 250 DE

ENERGY FLOW PATTERNS THROUGH FOOD WEBS IN NEOTROPICAL HEADWATER STREAMS OF THE BRAZILIAN SAVANNA

Secondary production is an important element of ecosystem ecology because it quantifies the roles of consumers in energy and nutrient transfers. We estimated production and resource consumption of stream macroinvertebrates, along with stream metabolism and organic matter, in three relatively undisturbed Brazilian savanna headwater streams. We sampled benthic macroinvertebrates and measured reach-scale metabolism from October 2015 to September 2016. Net ecosystem production varied from 8.1 to 35.8 g AFDM m-2 y-1, reflecting heterotrophic conditions. Total secondary production ranged from 11.0 to 13.5 g AFDM m-2 y-1. The shredder and predator functional groups contributed most to production, ranging from 21 - 39% and 20-49% of total production, respectively, and detrital pathways accounted for most energy flow in all streams. Shredders had the greatest mean consumption rates among the collected functional feeding groups, but still only ingested 3.4 to 8.1% of available resources, suggesting that production in these streams is not limited by resource availability. Our study provides the first secondary production and stream metabolism estimates for streams in the Brazilian savanna. Net heterotrophy is not necessarily expected in grassland streams, but detrital pathways dominated energy flow in the systems we examined.

Tropics
Functional Feeding Groups
Organic Matter

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Presenters/Authors

José Mello (), University of São Paulo, josemello@sc.usp.br;