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Abstract Hurricanes are major disturbances with important consequences to stream ecosystems as they create major floods and remove riparian vegetation. Understanding their impacts is a priority, as hurricane intensity is expected to increase due to global climate change.Mayfly assemblages in streams fill a diversity of ecological roles and functions. They are important consumers of algae by scraping benthic biofilms and detritivores associated with fine particles and leaf litter. Other taxa are filterers and even predators. Mayflies are also important prey items in aquatic and terrestrial food webs.Here, we assessed the effects of two consecutive hurricanes that impacted Puerto Rico in 2017 to understand how hurricane‐induced changes in the environment alter mayfly composition, secondary production and emergence.The study was conducted in the Luquillo Experimental Forest, Puerto Rico. Mayflies were sampled as nymphs and emerging adults for 6 months before and 17 months after hurricanes Irma and María hit the island in September 2017. Leaf litter inputs, canopy cover and chlorophyllaconcentrations were monitored along with mayflies.Mayfly assemblages were dominated by two genera of Leptophlebiidae before the hurricane,Neohagenulus (two species: N. julioTraver, 1938,N. luteolusTraver, 1938) andBorinquena (one species: B. carmencitaTraver, 1938). Both genera decreased in density after the hurricanes and were replaced with the BaetidaeCloeodes maculipesTraver, 1938 as the dominant taxon. This pattern was observed in both nymph and emerging adult densities.The secondary production of Leptophlebiidae species was highest before hurricane disturbance, with the BaetidaeC. maculipesshowing the opposite pattern.Neohagenulushad an annual production of 445 mg m−2 year−1,C. maculipesof 153 mg m−2 year−1andB. carmencitaof 68 mg m−2 year−1.Overall, the mayfly assemblages in our studied stream are vulnerable to hurricane disturbances. Expected increases in hurricane impacts might result in assemblage shifts that could change assemblage composition and alter energy flows within the ecosystem.
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Contrasting responses of black fly species (Diptera: Simuliidae) to experimental whole‐stream warming
Abstract As global temperatures continue to rise, assessment of how species within ecological communities respond to shifts in temperature has become increasingly important. However, such assessments require detailed long‐term observations or ecosystem‐level manipulations that allow for interactions among species and the potential for species dispersal and exchange with the regional species pool.We examined the effects of experimental whole‐stream warming on a larval black fly assemblage in southwest Iceland. We used a paired‐catchment design, in which we studied the warmed stream and a nearby reference stream for 1 year prior to warming and 2 years during warming and estimated population abundance, biomass, secondary production, and growth rates for larvae of three black fly species.Experimental warming by 3.8°C had contrasting effects on the three black fly species in the assemblage. The abundance, biomass, growth, and production ofProsimulium ursinumdecreased in the experimental stream during the warming manipulation. Despite increasing in the reference stream, the abundance, biomass, and production of another species,Simulium vernum, decreased in the experimental stream during warming.In contrast, warming had an overall positive effect onSimulium vittatum. While warming had little effect on the growth of overwintering cohorts ofS. vittatum, warming led to an additional cohort during the summer months and increased its abundance, biomass, and production. Overall, family‐level production was enhanced by warming, despite variation in species‐level responses.Our study illustrates that the effects of climate warming are likely to differ even among closely related species. Moreover, our study highlights the need for further investigation into the uneven effects of warming on individual species and how those variable effects influence food web dynamics and ecosystem function.
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- Award ID(s):
- 1757351
- PAR ID:
- 10456645
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Freshwater Biology
- Volume:
- 65
- Issue:
- 10
- ISSN:
- 0046-5070
- Page Range / eLocation ID:
- p. 1793-1805
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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