Tatiane Mary Gogola, Pedro Rogério Leandro da Silva, Anderson Luiz Maciel, Dirceu Baumgartner, Pitágoras Augusto Piana, Paulo Vanderlei Sanches
{"title":"Fish functional biotic simplification in a Neotropical reservoir: An approach from the ichthyoplankton","authors":"Tatiane Mary Gogola, Pedro Rogério Leandro da Silva, Anderson Luiz Maciel, Dirceu Baumgartner, Pitágoras Augusto Piana, Paulo Vanderlei Sanches","doi":"10.1111/eff.12729","DOIUrl":null,"url":null,"abstract":"<p>Ecosystem services provided by communities are related to the diversity of functional traits, and biotic functional simplification occurs when this diversity is reduced. Thus, we used the approach of functional indices, applied to the abundance of fish larvae and traits of the spawning stock, to evaluate the spatial and temporal variations in the functional diversity of the fish community of a Neotropical reservoir. The following hypotheses were tested: (i) different environmental conditions between reproductive periods lead to temporal variations in the functional diversity of the community, and (ii) the spatial heterogeneity (longitudinal and lateral) of the environmental conditions formed in the reservoir causes functional biotic simplification to occur from lotic towards lentic areas since the original community was formed by rheophilic species. Larval collections were carried out monthly, at night, between October and March, from 2009 to 2016, with plankton nets equipped with a flowmeter in nine sample areas categorised into three longitudinal zones (fluvial-FLU, transition-TRA and lacustrine-LAC) and three sides (upper-UPP, middle-MID and lower-LOW). Water samples were obtained to measure the temperature and turbidity. Precipitation and reservoir quotas were obtained from official agencies. After the identification of captured larvae, we determined which species were present and used the functional traits of the adults (parental stock), obtained from specialised literature, and functional richness (FRic) and its corresponding standardised effect size (SES.FRic) were computed. The spatiotemporal variations in these indices were evaluated through the two-way block factorial MANOVA/ANOVA. Their association with environmental variables was inferred through multiple linear regression models. Altogether, 51,995 larvae were captured with the highest abundance in the period V, longitudinally in LAC and TRA and laterally in LOW. Among these, the functional indices were higher in periods IV and V. The highest values of FRic occurred longitudinally in FLU and laterally in LOW. Among the abiotic conditions, rainfall and water temperature were the most influential variables over functional indices and total larvae abundance. The results indicate that fish reproduction is linked to spatiotemporal variations in abiotic conditions confirming our first hypothesis. The second hypothesis was partially supported because functional biotic simplification was observed in the longitudinal gradient, with reductions in FRic in LAC. However, this reduction was not observed in the lateral gradient. We showed that the temporal variability of abiotic conditions is important for the high functional diversity of reservoirs.</p>","PeriodicalId":11422,"journal":{"name":"Ecology of Freshwater Fish","volume":null,"pages":null},"PeriodicalIF":1.6000,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Ecology of Freshwater Fish","FirstCategoryId":"97","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1111/eff.12729","RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"FISHERIES","Score":null,"Total":0}
引用次数: 0
Abstract
Ecosystem services provided by communities are related to the diversity of functional traits, and biotic functional simplification occurs when this diversity is reduced. Thus, we used the approach of functional indices, applied to the abundance of fish larvae and traits of the spawning stock, to evaluate the spatial and temporal variations in the functional diversity of the fish community of a Neotropical reservoir. The following hypotheses were tested: (i) different environmental conditions between reproductive periods lead to temporal variations in the functional diversity of the community, and (ii) the spatial heterogeneity (longitudinal and lateral) of the environmental conditions formed in the reservoir causes functional biotic simplification to occur from lotic towards lentic areas since the original community was formed by rheophilic species. Larval collections were carried out monthly, at night, between October and March, from 2009 to 2016, with plankton nets equipped with a flowmeter in nine sample areas categorised into three longitudinal zones (fluvial-FLU, transition-TRA and lacustrine-LAC) and three sides (upper-UPP, middle-MID and lower-LOW). Water samples were obtained to measure the temperature and turbidity. Precipitation and reservoir quotas were obtained from official agencies. After the identification of captured larvae, we determined which species were present and used the functional traits of the adults (parental stock), obtained from specialised literature, and functional richness (FRic) and its corresponding standardised effect size (SES.FRic) were computed. The spatiotemporal variations in these indices were evaluated through the two-way block factorial MANOVA/ANOVA. Their association with environmental variables was inferred through multiple linear regression models. Altogether, 51,995 larvae were captured with the highest abundance in the period V, longitudinally in LAC and TRA and laterally in LOW. Among these, the functional indices were higher in periods IV and V. The highest values of FRic occurred longitudinally in FLU and laterally in LOW. Among the abiotic conditions, rainfall and water temperature were the most influential variables over functional indices and total larvae abundance. The results indicate that fish reproduction is linked to spatiotemporal variations in abiotic conditions confirming our first hypothesis. The second hypothesis was partially supported because functional biotic simplification was observed in the longitudinal gradient, with reductions in FRic in LAC. However, this reduction was not observed in the lateral gradient. We showed that the temporal variability of abiotic conditions is important for the high functional diversity of reservoirs.
期刊介绍:
Ecology of Freshwater Fish publishes original contributions on all aspects of fish ecology in freshwater environments, including lakes, reservoirs, rivers, and streams. Manuscripts involving ecologically-oriented studies of behavior, conservation, development, genetics, life history, physiology, and host-parasite interactions are welcomed. Studies involving population ecology and community ecology are also of interest, as are evolutionary approaches including studies of population biology, evolutionary ecology, behavioral ecology, and historical ecology. Papers addressing the life stages of anadromous and catadromous species in estuaries and inshore coastal zones are considered if they contribute to the general understanding of freshwater fish ecology. Theoretical and modeling studies are suitable if they generate testable hypotheses, as are those with implications for fisheries. Manuscripts presenting analyses of published data are considered if they produce novel conclusions or syntheses. The journal publishes articles, fresh perspectives, and reviews and, occasionally, the proceedings of conferences and symposia.