The Effects of Brown Trout on the Trophic Webs of New Zealand Streams

Jellyman, Phillip G.; McHugh, Peter A.; Simon, Kevin S.; McIntosh, Angus R.

doi:10.1002/9781119268352.ch22

Cited by 8 publications

(8 citation statements)

References 90 publications

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“…For example, while trout may generally be not as well adapted to flood disturbance as native fish species in New Zealand (Leprieur et al., 2006; Woodford & McIntosh, 2011), in some catchments they have high flood resilience (Jellyman et al 2017), possibly as a result of confluences providing access between stable and disturbed reaches for potential recolonists. Native non‐migratory galaxiids, by contrast, are severely affected by predatory trout (Townsend & Crowl, 1991; McDowall, 2006; McIntosh et al., 2010), so to a certain extent flood‐disturbed streams, where trout abundances tend to be lower, provide a refuge from competition and predation (Jellyman et al 2017). However, disturbed streams are also harsh environments, so proximity to more stable conditions via confluences probably provides access for post‐flood recolonists, resulting in higher and more temporally stable galaxiid abundance around confluences of these two flow regimes.…”

Section: Discussionmentioning

confidence: 99%

Could spatial heterogeneity in flow disturbance drive temporal stability of native–invasive species co‐occurrence in riverscapes?

Boddy

McIntosh

2021

Freshwater Biology

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Spatial heterogeneity of abiotic influences like disturbance in riverscapes could play an important role in dispersal‐aided community stability. We tested if higher spatial variability in conditions around river confluences caused by different flood disturbance regimes in branches could possibly influence the stability of a fish assemblage dominated by strong negative interactions between non‐native trout and native galaxiid fishes. We used field surveys to evaluate the effects of disturbance‐driven differences between river branches on fish densities and temporal variation in the relative abundance of galaxiids. Three repeated electrofishing surveys were conducted in two reaches of all branches of eight confluences in Canterbury, New Zealand. We found the differences in flood disturbance regimes between the two stream branches joining at a confluence were associated with higher mean fish abundance and more temporal stability in the relative abundance of native fish. Conversely, when flood disturbance conditions in the two streams joining were similar, resulting in a homogeneous confluence, fish abundance was lower and temporal variability was higher. For homogeneous confluences, strong interactions between native galaxiids and invasive trout probably produced lower fish densities where rivers with low flow disturbance met, whereas when two highly flow‐disturbed rivers met, environmental harshness probably lowered fish densities. By comparison, enhanced galaxiid temporal stability at confluences containing both disturbed and stable river branches probably reflected the combined effects of refugia from trout predation in disturbed branches and refugia from flooding in stable branches. Overall, these results are likely to reflect the combined effects of population‐specific responses to physical heterogeneity and spatially variable interspecific interactions. They may mean that river network configuration, and confluences especially, could influence community stability through a habitat portfolio effect. Furthermore, it will be worth investigating further whether preservation or restoration of differences in flow disturbance conditions in riverscapes encourages higher ecosystem resilience in the face of global change.

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Section: Discussionmentioning

confidence: 99%

Could spatial heterogeneity in flow disturbance drive temporal stability of native–invasive species co‐occurrence in riverscapes?

Boddy

McIntosh

2021

Freshwater Biology

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“…However, these salmonids have been introduced and/or stocked outside their native range virtually around the world, mainly as objects of recreational fishery. As a result, several countries report an adverse ecological impact after their introduction [43][44][45][46][47]. Although brown trout are of limited interest in production aquaculture [48] (except the commercially important Atlantic salmon), brown trout have been and still are objects of intense investigations in various types of studies [12].…”

Section: Discussionmentioning

confidence: 99%

Present and Future Salmonid Cytogenetics

Gaffaroğlu

Majtánová

Symonová

et al. 2020

Genes

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Salmonids are extremely important economically and scientifically; therefore, dynamic developments in their research have occurred and will continue occurring in the future. At the same time, their complex phylogeny and taxonomy are challenging for traditional approaches in research. Here, we first provide discoveries regarding the hitherto completely unknown cytogenetic characteristics of the Anatolian endemic flathead trout, Salmo platycephalus, and summarize the presently known, albeit highly complicated, situation in the genus Salmo. Secondly, by outlining future directions of salmonid cytogenomics, we have produced a prototypical virtual karyotype of Salmo trutta, the closest relative of S. platycephalus. This production is now possible thanks to the high-quality genome assembled to the chromosome level in S. trutta via soft-masking, including a direct labelling of repetitive sequences along the chromosome sequence. Repetitive sequences were crucial for traditional fish cytogenetics and hence should also be utilized in fish cytogenomics. As such virtual karyotypes become increasingly available in the very near future, it is necessary to integrate both present and future approaches to maximize their respective benefits. Finally, we show how the presumably repetitive sequences in salmonids can change the understanding of the overall relationship between genome size and G+C content, creating another outstanding question in salmonid cytogenomics waiting to be resolved.

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“…The fish fauna in New Zealand is strongly influenced by distance to the ocean, so sites in Westland and Banks Peninsula typically have higher fish species diversity than Canterbury high country streams. The native fish fauna has been strongly influenced by introduced salmonids, particularly brown trout (Jellyman, McHugh, Simon, Thompson, & McIntosh, ), which are present throughout the South Island. In contrast, benthic invertebrate communities have few introduced species present and in unmodified streams these faunas are often comprised of a remarkably similar suite of genera ( Deleatidium , Coloburiscus , Nesameletus [Ephemeroptera]; Stenoperla , Zelandoperla , Zelandobius [Plecoptera]; Hydrobiosis , Psilochorema , Pycnocentria , Olinga , Aoteopsyche [Trichoptera]; Archichauliodes [Megaloptera]; and Potamopyrgus [Gastropoda]; Winterbourn, Rounick, & Cowie, ).…”

Section: Methodsmentioning

confidence: 99%

“…The native fish fauna has been strongly influenced by introduced salmonids, particularly brown trout (Jellyman, McHugh, Simon, Thompson, & McIntosh, 2018), which are present throughout the South Island. In contrast, benthic invertebrate communities have few introduced species present and in unmodified streams these faunas are often comprised of a remarkably similar suite of genera…”

Section: Study Areamentioning

confidence: 99%

Disturbance‐mediated consumer assemblages determine fish community structure and moderate top‐down influences through bottom‐up constraints

Jellyman

McIntosh

2020

Journal of Animal Ecology

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1. Disturbance is a strong structuring force that can influence the strength of species interactions at all trophic levels, but controls on the contributions to community structure of top-down and bottom-up processes across such gradients remain poorly understood. Changes in the composition of predator and consumer assemblages, and their associated traits, across gradients of environmental harshness (e.g. flooding), are likely to be a particularly important influence on the strength of S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section. How to cite this article: Jellyman PG, McIntosh AR. Disturbance-mediated consumer assemblages determine fish community structure and moderate top-down influences through bottom-up constraints.

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The Effects of Brown Trout on the Trophic Webs of New Zealand Streams

Cited by 8 publications

References 90 publications

Could spatial heterogeneity in flow disturbance drive temporal stability of native–invasive species co‐occurrence in riverscapes?

Could spatial heterogeneity in flow disturbance drive temporal stability of native–invasive species co‐occurrence in riverscapes?

Present and Future Salmonid Cytogenetics

Disturbance‐mediated consumer assemblages determine fish community structure and moderate top‐down influences through bottom‐up constraints

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