Importance of long-term intensive monitoring programs for understanding multiple drivers influencing Lake Ontario zooplankton communities

Bowen, Kelly L.; Currie, Warren J. S.; Niblock, H.; Ward, Colette; Metcalfe, Brent W.; Cuddington, K.M.D.; Johnson, Terry B.; Koops, Marten A.

doi:10.1016/j.jglr.2022.03.016

Cited by 9 publications

(9 citation statements)

References 75 publications

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“…Broad restoration targets like an increase in warmwater native piscivore species were able to be checked intuitively and quickly both on a regional and site‐specific level before delving into species‐specific differences as needed. The community metric approach applied here and ease of its use could benefit future assessments, especially under changing management requirements and environmental conditions to allow us to gain more insights over the course of the restoration monitoring (Barnes et al, 2020; Bouwes et al, 2016; Bowen et al, 2022). Multi‐metric indices like index of biotic integrity (IBI) have been used within the Great Lakes context (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…This approach can be useful for highly abundant species that can inflate overall catch and for capturing community dominance changes (e.g. alewife; emerald shiner; Bowen et al, 2022). For instance, a specific species or type can have the exact same T A B L E 2 Traits and sub-traits included in the cluster analyses as well as proxies relating to community restoration goals.…”

Section: Community Traits and Habitat Associations Along The Toronto ...mentioning

confidence: 99%

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A multi‐metric index for assessing two decades of community responses to broad‐scale shoreline enhancement and restoration along the Toronto waterfront

Theis,

Cartwright,

Chreston

et al. 2024

Aquatic Conservation

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Biodiversity and habitat loss due to historical and continued urbanization and anthropogenic development require continuous efforts to abate ongoing environmental decline. Restoration and enhancement efforts that aim to address biodiversity and habitat loss, have shown some promise at providing suitable habitat for species in the more urbanized nearshore areas of Lake Ontario. Using 20 years of fish community data from the Toronto waterfront, this study examined ecosystem responses in a spatio‐temporal context across wetland and embayment ecotypes. The goals of this study were to (1) assess how fish communities have changed over time in restored, reference and more and less urbanized nearshore ecosystems and (2) determine if restored and enhanced habitats meet the defined fish community management targets. Fish communities were assessed through a newly developed multi‐metric index based on species life history traits and habitat associations like trophic and thermal guild. Fish communities along the waterfront have transitioned from cool and coldwater pelagic species to a higher proportion of native warmwater species, many of them piscivores, associated with cover and vegetation, that meet community targets. These changes are more pronounced at the largest restoration site ‘Tommy Thompson Park’, where community indices approach natural reference levels. This result indicates the benefits and effectiveness of the decade‐long restoration efforts and subsequent monitoring of responses. Our results underline that large‐scale restoration projects in urbanized settings can be of vital importance for freshwater conservation efforts, as well as application scenarios for multi‐metric community indices, and will play an even larger role when looking at Lake Ontario or the Great Lakes as a whole.

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Section: Discussionmentioning

confidence: 99%

Section: Community Traits and Habitat Associations Along The Toronto ...mentioning

confidence: 99%

A multi‐metric index for assessing two decades of community responses to broad‐scale shoreline enhancement and restoration along the Toronto waterfront

Theis,

Cartwright,

Chreston

et al. 2024

Aquatic Conservation

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“…Zooplankton available for larval coregonines, including cyclopoids, have declined in both the Bay of Quinte (Bowen et al, 2022;Hoyle et al, 2011) and Chaumont Bay (Figary et al, 2023), which could foster competition for zooplankton. Yet, species-specific differences in body length and gape size may act to partition consumable size classes of edible zooplankton between the two species when they co-occur.…”

Section: Discussionmentioning

confidence: 99%

“…Cyclopoid copepods are an important prey source for both species (Davis & Todd, 1998; Hoyle et al, 2011; Pothoven et al, 2014; Pothoven, 2020; Lucke et al, 2020), which is likely due to their large size relative to larval gape limitations and high abundances when larval coregonines begin exogenously feeding. Zooplankton available for larval coregonines, including cyclopoids, have declined in both the Bay of Quinte (Bowen et al, 2022; Hoyle et al, 2011) and Chaumont Bay (Figary et al, 2023), which could foster competition for zooplankton. Yet, species‐specific differences in body length and gape size may act to partition consumable size classes of edible zooplankton between the two species when they co‐occur.…”

Section: Discussionmentioning

confidence: 99%

Larval cisco and lake whitefish exhibit high distributional overlap within nursery areas

Brown,

Rudstam,

Holden

et al. 2023

Ecology of Freshwater Fish

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Coregonine fishes, including lake whitefish (Coregonus clupeaformis) and cisco (C. artedi), are socioecologically important in the Laurentian Great Lakes and of conservation concern, but the processes driving recruitment variability are unclear. In Lake Ontario, cisco and lake whitefish exhibit similar spawning behaviours and early life histories, but population trajectories are diverging. One hypothesis is that sympatric cisco and lake whitefish larvae occupy distinct habitats and experience dissimilar local environmental conditions, despite co‐occurrence within nursery areas. We described the spatiotemporal distributions of larval cisco and lake whitefish among multiple Lake Ontario embayment nursery areas, characterised physical habitat features associated with their distributions, determined the degree of spatial habitat partitioning between species and evaluated how habitat niche divergence occurred along an ontogenetic progression. Both species were widely distributed across larval nursery areas, though lake whitefish were less abundant and more narrowly distributed than cisco. Within the yolk sac stage, lake whitefish occupied more nearshore, shallower and colder waters than cisco, indicating potential habitat niche partitioning between congeners. However, distributional differences were subtle and likely driven by differential hatch timing and staggered ontogenetic habitat shifts. Combined, our results illustrate similar habitat use between cisco and lake whitefish through the larval stage and demonstrate that ontogeny and species‐specific phenology influence habitat use for these species. This study provides additional evidence that the early life histories of cisco and lake whitefish are highly similar and does not support the hypothesis that larval habitat use differences are a major driver of differential recruitment success for these species.

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“…We could then assess what the fish community looks like in an average electrofishing run at an ecotype and year. This can be helpful since increases or decreases in catch (for each sampling run) can mask proportionate changes and shifts in communities, especially with high catch differences among runs and with highly abundant species that can inflate overall catch (e.g., Alewife; [ 14 ]; S3 Fig ). For instance, a specific species or type can have the same abundance across two sites but very different relative abundance depending on the rest of the site community.…”

Section: Methodsmentioning

confidence: 99%

Nearshore fish community changes along the Toronto waterfront in accordance with management and restoration goals: Insights from two decades of monitoring

Theis,

Chreston,

Wallace

et al. 2024

PLoS ONE

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Aquatic habitat in the Greater Toronto Area has been subject to anthropogenic stressors. The subsequent aquatic habitat degradation that followed led to the Toronto and Region waterfront being listed as an Area of Concern in 1987. Thus, extensive shoreline and riparian habitat restoration have been implemented as part of the Toronto and Region Remedial Action Plan in conjunction with local stakeholders, ministries, and NGOs in an overall effort to increase fish, bird, and wildlife habitat. A key aspect of current fish habitat restoration efforts, monitored by Toronto and Region Conservation Authority, is to account for long-term community changes within the target ecosystem to better understand overall changes at a larger spatial scale. Here we use electrofishing data from the past 20 years with over 100,000 records and across 72km of coastline to show how declines and fluctuations in fish biomass and catch along the waterfront are driven by a few individual species across three main ecotypes, such as coastal wetlands, embayments, and open coast sites, with the remaining species showing a high level of stability. Using community traits and composition for resident species we demonstrate native warmwater species have become more dominant along the waterfront in recent years, suggesting that restoration efforts are functioning as intended. Additionally, piscivore and specialist species have increased in their relative biomass contribution, approaching existing restoration targets. Altogether this waterfront-wide evaluation allows us to detect overall changes along the waterfront and can be beneficial to understand community changes at an ecosystem level when implementing and monitoring restoration projects.

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Importance of long-term intensive monitoring programs for understanding multiple drivers influencing Lake Ontario zooplankton communities

Cited by 9 publications

References 75 publications

A multi‐metric index for assessing two decades of community responses to broad‐scale shoreline enhancement and restoration along the Toronto waterfront

A multi‐metric index for assessing two decades of community responses to broad‐scale shoreline enhancement and restoration along the Toronto waterfront

Larval cisco and lake whitefish exhibit high distributional overlap within nursery areas

Nearshore fish community changes along the Toronto waterfront in accordance with management and restoration goals: Insights from two decades of monitoring

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