Chironomidae (Diptera: Insecta) in oceanic islands: New records for the Azores and biogeographic notes

Raposeiro, Pedro M.; Hughes, Samantha Jane; Costa, Ana C.

doi:10.1051/limn/2009012

Cited by 12 publications

(7 citation statements)

References 21 publications

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“…The enhanced hydrodynamic water currents, especially in Transect 3, suggested by the coarser sedimentary particles presence, would favour the occurrence of higher flow conditions. These hydrodynamic conditions were confirmed by the presence of several taxa associated to lotic systems and well represented in Azorean streams (Gonçalves et al 2015;Raposeiro et al 2011;Raposeiro et al 2009;Raposeiro et al 2013), such as Cocconeis euglypta, Eunotia exigua, Fragilaria capucina and Eolimna uthermoehlii, for the diatom assemblages, and Orthocladius sp. and Pseudosmitthia sp.…”

Section: Sedimentation and Taphonomic Processes Affects The Spatial Dmentioning

confidence: 61%

Causes of spatial distribution of subfossil diatom and chironomid assemblages in surface sediments of a remote deep island lake

et al. 2018

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Until recently, the distribution of diatom and chironomid species assemblages and their attributes (e.g. species richness and diversity) in relation to water depth and sedimentary environments have been identified but not quantified. The influence of environmental variables on assemblage distribution and taxa richness in a deep, monomitic lake in São Miguel Island is assessed. Attention is given to community variation along a depth gradient. Surface-sediment diatom and chironomid assemblages were collected along three transects from shoreline to the centre deep basin of the lake at a resolution of 1 m water depth. Linear and unimodal regressions were used to test taxon richness, taxon diversity and taxon evenness versus water depth of each transept. A hump-shaped relationship between species richness and water depth was noted, with a peak occurring at mid depth levels, meaning that samples located at that depth better represented the total subfossil assemblage of lake Azul. Also, diatom and chironomid assemblages in Lake Azul, and taphomomic effects, were influenced by sedimentary environmental processes depending on the lake morphology. Based on the present results, in order to determine ideal coring locations for lake studies combining diatom and chironomid analyses, an understanding of the spatial distribution of these biota is essential.

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Section: Sedimentation and Taphonomic Processes Affects The Spatial Dmentioning

confidence: 61%

Causes of spatial distribution of subfossil diatom and chironomid assemblages in surface sediments of a remote deep island lake

et al. 2018

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“…The low contribution of stream macroinvertebrates to litter decomposition in oceanic islands has been reported before, and is attributed to the low abundance and richness of shredders in these isolated systems (Larned, 2000;Benstead et al, 2009;MacKenzie et al, 2013;Raposeiro et al, 2014). Age, area and distance to the mainland are key factors ruling the colonisation of oceanic islands by organisms (Raposeiro, Hughes & Costa, 2009, and explain why remote islands have low diversity and abundance of shredders (Benstead et al, 2009;MacKenzie et al, 2013;Raposeiro et al, 2013). In Azorean streams, in particular, only a few shredder taxa have been identified: the iso- Fig.…”

Section: Discussionmentioning

confidence: 87%

Leaf litter decomposition in remote oceanic island streams is driven by microbes and depends on litter quality and environmental conditions

et al. 2016

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Summary Leaf litter decomposition is an important process in many streams. The flow of carbon and nutrients to higher trophic levels generally depends on litter characteristics and environmental conditions, and is driven by the activities of microbes and invertebrate shredders. However, little is known about what drives litter decomposition in oceanic islands, where invertebrate communities are species‐poor. In this study, we assessed the relative importance of litter quality and environmental conditions on the biological colonisation and decomposition of litter exposed to and protected from macroinvertebrates, in the Azores archipelago, North Atlantic Ocean. Three leaf litter species with distinct physical and chemical characteristics (Acacia melanoxylon, Clethra arborea and Pittosporum undulatum) were incubated in six streams with distinct water characteristics. Coarse and fine mesh bags were used to isolate the relative role of macroinvertebrates on litter decomposition. Incubation of litter took place in late spring – early summer and lasted for up to 56 days. No significant differences in litter decomposition rates were found between coarse and fine mesh bags suggesting that microbes, especially aquatic hyphomycetes, are the key players in litter decomposition in these island streams. Litter decomposition rates were inversely proportional to initial lignin concentration: A. melanoxylon 0.0080 day−1, C. arborea 0.0121 day−1, P. undulatum 0.0292 day−1, on average across streams. Litter decomposition rates and associated decomposers differed among streams, suggesting that environmental conditions (e.g. nutrient concentration) may be important moderators of biological activities in these streams, as found for continental streams. Species richness, fungal biomass and reproductive activity of aquatic hyphomycetes on decomposing litter were recorded in Atlantic islands for the first time and were at levels similar to those found for continental streams. High microbial activities in Atlantic island streams ensure litter decomposition when shredder abundance is low.

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“…Fish preferentially prey on large insects (Pope and Hannelly, 2013), such as Ephemeroptera, Trichoptera and Odonata, which are poorly represented in the Azores archipelago (Raposeiro et al, 2012(Raposeiro et al, , 2016. Chironomids, however, being the most abundant and diverse family of freshwater macroinvertebrates in the Azores archipelago (Raposeiro et al, 2009(Raposeiro et al, , 2012, are the available prey for introduced predators.…”

Section: Discussionmentioning

confidence: 99%

“…However, the ecological requirements of chironomid taxa have universal validity because even though the species might not be the same from one region to another, genera display comparable ecological requirements (Brundin, 1956;Mousavi et al, 2002;Oliver, 1971;Saether, 1975). Many of the chironomid genera present in Lake Azul have a Holarctic distribution (Raposeiro et al, 2009) and their ecology is well studied, and so we can infer tentative conclusions about their response to predator introductions in Azorean lakes.…”

Section: Discussionmentioning

confidence: 99%

“…Chironomids, one of the most abundant and diverse families of freshwater macroinvertebrates in the Azores archipelago (Raposeiro et al, 2011b;Raposeiro et al, 2009), are an important element in aquatic food webs, constituting approximately 50% of secondary production in lakes (Armitage et al, 1995). Consequently, chironomids play a crucial role in benthic food webs and in the trophic structure of ecosystems (Armitage et al, 1995).…”

Section: Accepted Manuscriptmentioning

confidence: 99%

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Impact of the historical introduction of exotic fishes on the chironomid community of Lake Azul (Azores Islands)

Raposeiro

Rubio

González

et al. 2017

Palaeogeography, Palaeoclimatology, Palaeoecology

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Little is known about the effect of top predator introduction in historically fishless communities, especially on remote islands. This issue is important because it might strongly affect climate reconstructions derived from biota assemblages such as chironomids. Head capsule larval remains of chironomids have been studied in a 660 years lacustrine sedimentary sequence from Lake Azul (Sao Miguel Island, Azores archipelago) to assess the extent and timescale of the effect of the predator introduction occurring in this historically fishless lake. Analysis of similarity showed that the chironomid assemblage was statistically different before and after predator introduction (R=0.78; p<0.001). Abundance of chironomids was about 40% greater in the fishless lake period compared to the period in the presence of predator. Results show major change in chironomid assemblage coinciding with the first time of goldfish introduction (around 1790 AD), followed by carp (1890 AD) and pike (1979 AD) introductions. The composition of feeding group guilds changed following a pattern characterized by a decrease in abundance of detritivorous and predaceous taxa and an increase in abundance of grazing chironomid taxa. This study suggests that predator introduction was the most important factor affecting the chironomid assemblages in this natural, Azorean fishless lake, but predators did not affect all chironomid species. Other external forcings like major climate oscillations, anthropogenic activities in the catchment basin, and volcanic eruptions seem to play an additional role. The latest stage of the warm and arid Medieval Climate Anomaly (1000-1300 AD) favoured the occurrence of some warm-adapted chironomid taxa, which were absent through the Little Ice Age (ca. 1450-1850 AD) cool period.

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Chironomidae (Diptera: Insecta) in oceanic islands: New records for the Azores and biogeographic notes

Cited by 12 publications

References 21 publications

Causes of spatial distribution of subfossil diatom and chironomid assemblages in surface sediments of a remote deep island lake

Causes of spatial distribution of subfossil diatom and chironomid assemblages in surface sediments of a remote deep island lake

Leaf litter decomposition in remote oceanic island streams is driven by microbes and depends on litter quality and environmental conditions

Impact of the historical introduction of exotic fishes on the chironomid community of Lake Azul (Azores Islands)

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