Seasonality and interspecific competition shape individual niche variation in co-occurring tetra fish in Neotropical streams
Neves, Mayara; Costa-Pereira, Raul; Delariva, Rosilene Luciana; Fialho, Clarice Bernhardt (2020), Seasonality and interspecific competition shape individual niche variation in co-occurring tetra fish in Neotropical streams, Dryad, Dataset, https://doi.org/10.5061/dryad.tqjq2bvx5
We sampled six headwater streams (2nd and 3th orders – Figure S1, Table S1) and collected all small characids species found: Psalidodon aff. paranae (Eigenmann, 1914), Psalidodon bifasciatus (Garavello & Sampaio, 2010), Psalidodon aff. gymnodontus (Eigenmann, 1911) and Bryconamericus ikaa Casciotta, Almirón & Azpelicueta, 2004. We sampled fish in July (winter) and December (summer) 2017. According to the historical climate series of the region, 2017 represents a typical year with cold and dry winter, and hot and rainy summer . In each season, we realized one sampling event per stream. We conducted the fish sampling in reaches of 50 m using electrofishing with three passes of 40 min. After capture, specimens were anaesthetized, fixed in 10% formalin, and preserved in 70% alcohol. We collected fish with authorization from the Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio) (license number 25039-1) and approved by the Ethics Committee on Animal Use of the Universidade Federal do Rio Grande do Sul (CEUA – 32734) in accordance with protocols in their ethical and methodological aspects for the use of fish.
We identified specimens in the laboratory according to specific identification keys (Baumgartner et al., 2012; Ota, Deprá, Graça & Pavanelli, 2018). To avoid bias caused by ontogenetic variations, we selected 403 adult individuals (Table S2). Voucher specimens were deposited in the fish collection of the Departamento de Zoologia, Universidade Federal do Rio Grande do Sul. We analyzed the stomach contents under stereoscopic and optical microscope and feeding items were identified to the lowest possible taxonomic level, using specific literature for the algae (Bicudo & Bicudo, 1970) and invertebrates (Mugnai, Nessimian & Baptista, 2010). We quantified the proportion of feeding items in each individual’s diet following the volumetric method (Hyslop, 1980) using graduated test tubes and a glass counting plate (Hellawell & Abel, 1971).
Conselho Nacional de Desenvolvimento Científico e Tecnológico, Award: 152847/2016-2