Firth, B., Poesch, M.S., Koops, M., Power, M. and D.A.R. Drake. (2021) Diet overlap of common and at-risk riverine benthic fishes before and after Round Goby (Neogobius melanostomus) invasion. Biological Invasions 23(1): 1-14.

Citation: Firth, B., Poesch, M.S., Koops, M., Power, M. and D.A.R. Drake. (2021) Diet overlap of common and at-risk riverine benthic fishes before and after Round Goby (Neogobius melanostomus) invasion. Biological Invasions 23(1): 1-14. 

Abstract

Round Goby (Neogobius melanostomus) has invaded high diversity tributaries of the Laurentian Great Lakes, including those supporting multiple species of conservation concern. The extent and magnitude of ecological impacts on benthic riverine fishes is poorly understood, especially changes in dietary overlap and feeding strategy. We used a before-after study design to examine the impact of Round Goby on native benthic riverine fishes, including the Threatened Eastern Sand Darter (Ammocrypta pellucida) in the Sydenham River, Ontario, Canada. To evaluate shifts in diet overlap and feeding strategy, fishes were collected with multiple gears and the direct (diet overlap with the invader) and potential indirect (diet overlap among the native benthic fishes) impacts of Round Goby were assessed. Before the arrival of Round Goby, there were a total of 6 ecologically significant diet overlaps among the studied native benthic fishes. Following the arrival of Round Goby, there were 20 ecologically significant diet overlaps, with 6 out of 8 species, including Eastern Sand Darter, showing significant diet overlap with Round Goby. Fishes exhibiting significant dietary overlap with Round Goby shifted feeding strategies to become more specialized, a change in feeding consistent with potential competitive effects. Although the long-term consequences of invasion-induced dietary and feeding shifts remain poorly understood, increased competitive interactions suggested by dietary overlap may be occurring between Round Goby and native benthic riverine fishes and may exacerbate the observed declines of native species.

Hamilton, K. (2020) Streamflow is changing in rivers across Alberta: assessing regional variation in changing hydrologic indices.

Thesis Title: Streamflow is changing in rivers across Alberta: assessing regional variation in changing hydrologic indices.

Author: Kyle Hamilton

Abstract

The flow regime is a crucial factor in the well-being of aquatic and riparian ecosystems. Many components of those ecosystems, ranging for nutrient transport to morphology, are impacted by various hydrologic parameters. The parameters help define and quantify five important hydrologic regime characteristics: magnitude, duration, timing, frequency, and rate of change. Our study utilized the Indicators of Hydrologic Alteration (IHA) indices to (1) determine how various ecologically relevant components of streamflow are changing across Alberta’s various biomes; and (2) examine the similarities and differences between streamflow trends and climate trends. The overarching goal of these objectives is to create a foundation upon which water management practices can be created or modified.

Region-specific water management is required to balance the residential, commercial, and industrial water needs of a particular region with ecological concerns and conservation initiatives. Understanding the trends in hydrologic parameters is an important step in recognizing the vulnerabilities of each region. Streamflow at Water Survey of Canada stations was assessed for linear trends using a Mann-Kendall Trend Analysis. Our approach of assessing overall trends on a regional basis was validated when looking at trends in magnitude. The average daily flow rate for spring and summer months was found to be decreasing in the boreal region but increasing in the grassland region. Other hydrologic indices were found to exhibit significant trends on a province-wide level. Annual minimum and maximum flow conditions over a variety of durations were observed to be merging across the province. Similarly, the rate of change of streamflow between consecutive days is decreasing across Alberta.

To determine whether these results were the function of climate oscillation patterns, a composite analysis was performed to determine the effect of the El Niño–Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) on hydrologic indices. Only 8% of parameters were found to be significantly influenced by PDO patterns and 4% influenced by ENSO patterns.

Card, J.*, Hasler, C., Ruppert, J.*Donadt, C.* and M.S. Poesch. (2020) A three-pass electrofishing removal strategy is not effective for eradication of Prussian Carp in a North American stream network. Journal of Fish and Wildlife Management 11(2): 485-493.

Citation: Card, J., Hasler, C., Ruppert, J., Donadt, C.* and M.S. Poesch. (2020) A three-pass electrofishing removal strategy is not effective for eradication of Prussian Carp in a North American stream network. Journal of Fish and Wildlife Management 11(2): 485-493. 

Abstract

Prussian Carp Carassius gibelio, also referred to as Gibel Carp, is a destructive aquatic invasive species, recently, found in Alberta Canada. Three-pass electrofishing is a potential approach to control some aquatic invasive fish species in stream habitats. The objectives of this study were to: 1) determine the efficacy of this strategy to control Prussian Carp in connected streams; and, 2) assess whether removal success was influenced by population size or the distance to the introduction site. We sampled sites using electrofishing in tributaries of the Red Deer River in both the summer and fall. Prussian Carp were detected at all sites prior to removal, with > 90 % probability of detection of this species within the first 120 m of electroshocking efforts. Overall, removal was deemed unsuccessful. We found that abundances of Prussian Carp were significantly higher post-removal. Removal success was significantly related to distance to the introduction site, suggesting that removal may be useful in targeted situations close to the edge of the invasion front. Additional removal and control strategies are needed by managers.

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*Lab members:  Jamie Card, Jonathan Ruppert, Caitlyn Donadt and  Mark Poesch. Check out opportunities in the lab!

McPherson, M. (2020) Habitat use by fluvial Arctic Grayling (Thymallus arcticus) across life stages in northern mountain streams.

Thesis Title: Habitat use by fluvial Arctic Grayling (Thymallus arcticus) across life stages in northern mountain streams.

Author: Morag McPherson 

Abstract

Northern aquatic ecosystems face increasing pressures from climate change and natural resource development, raising conservation concerns for species in these understudied regions.  The Arctic Grayling (Thymallus arcticus) is a widely distributed, but sensitive, northern freshwater fish that is a good indicator of general aquatic health. In the Northwest Territories (NWT), there has been little focus on studying riverine Arctic Grayling populations or their use of stream habitats within mountain river watersheds. The purpose of my research is to characterize fluvial Arctic Grayling distribution among mountain streams in the NWT, and to determine habitat characteristics and ecological factors that influence Arctic Grayling habitat use across life stages. Sampling sites (n=183) were selected in four sub-basins within the Little Nahanni River watershed in the southwest NWT. In the summer of 2015, each site (100 meters in length) was electrofished and stream habitat parameters were measured. Arctic Grayling were collected for biological analyses of age, size, weight, and reproductive development. Results showed shifts in Arctic Grayling development by size and age class that corresponded with shifts in distribution observed across the study streams. From these findings, four distinct post-emergence life stages for Arctic Grayling were identified: young-of-year (YOY), juvenile, sub-adult and adult. Step-wise logistic regression was used to explore the relationship between the occurrence of Arctic Grayling life stages and stream habitat characteristics. Multivariate regression tree (MRT) analysis was used to identify environmental thresholds and habitat-based life stage segregation, and redundancy analysis (RDA) was used to determine potential life stage-specific habitat correlations. Differences emerged in how Arctic Grayling life stages use habitat across a range of available stream conditions. YOY Arctic Grayling were found exclusively in low elevation, low gradient habitat dominated by silty-sand substrate with average water temperatures >10oC. Similarly, juvenile Arctic Grayling occupied low elevation, warm water stream habitat, but associated strongly with run habitats, as well as showing movement towards cooler water temperatures and more riffle dominated habitats. Sub-adult Arctic Grayling used the widest range of habitats across the study area, being found at a range of elevations and water temperatures, demonstrating the ability of this life stage to use a diversity of available habitats. Sub-adults showed a relationship to in-stream riffle, pool, and cascade-boulder habitats. Adults had a strong correlation to elevation and water temperature, using habitats with high elevation (>1200 m) and low temperature (7oC), and increased proportions of pool and boulder habitat. The four sub-watersheds studied provided distinct stream habitats and Arctic Grayling life stages separated across the habitat types, advancing our understanding of the life cycle habitat requirements for fluvial populations in mountain systems. It provides insight on the important and potential limiting factors, such as availability of warm water habitats, to population success in cold regions. The dynamic nature of Arctic Grayling habitat use in mountain streams highlights the need to consider habitat complexes at the watershed scale when defining species life stage requirements, managing habitats, monitoring populations, and assessing potential impacts into the future. Improved understanding of the distribution, habitat requirements and ecology of different life history types and life stages of Arctic Grayling is crucial for the effective management and monitoring of this species in northern environments

Theis, S.*, Ruppert, J.W.R*, Roberts, K.*, Koops, M., Minns, K. and M.S. Poesch. (2020) Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters. Conservation Biology 34(1) 41-53.

Citation: Theis, S.*, Ruppert, J.W.R*, Roberts, K.*, Koops, M., Minns, K. and M.S. Poesch. (2020) Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters. Conservation Biology 34(1) 41-53.

Abstract

Land‐use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland, creek), offsetting measure (e.g., enhancement, restoration, creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.

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*Lab members:  Sebastian Theis, Jonathan Ruppert, Karling Roberts and  Mark Poesch. Check out opportunities in the lab!

Nelson-Chorney, H.*, Carli, C.M., Davis, C.S., Vinebrooke, R.D., Poesch, M.S., and M.K. Taylor (2019) Environmental DNA in lake sediment reveals biogeography of native genetic diversity. Frontiers in Ecology and Evolution 17: 313-318.

Citation: Nelson-Chorney, H., Carli, C.M., Davis, C.S., Vinebrooke, R.D., Poesch, M.S., and M.K. Taylor (2019) Environmental DNA in lake sediment reveals biogeography of native genetic diversity. Frontiers in Ecology and Evolution 17: 313-318.

Abstract

Understanding the historical distributions of species is vital to the conservation and restoration of native species, yet such information is often qualitative. We show that the paleolimnological history of threatened freshwater fishes can be reconstructed using species‐diagnostic markers amplified from environmental DNA deposited in lake sediments (lake sedDNA). This method was validated through the detection of lake sedDNA from non‐native trout (Yellowstone cutthroat trout, Oncorhynchus clarkii bouvieri), which corroborated historical records of human‐mediated introductions. We also discovered native trout (westslope cutthroat trout, Oncorhynchus clarkii lewisi) lake sedDNA that predated human‐mediated introductions of freshwater fishes in a watershed with high topographical relief. This unexpected result revealed that the westslope population was of native origin and requires immediate conservation protection. Our findings demonstrate that lake sedDNA can be used to determine the colonization history of freshwater fishes and the structure of ecosystems, aiding in the identification of native ranges, novel native diversity, and introductions of non‐native species. 

*Lab members:   Hedin Nelson-Chorney, Mark Poesch. Check out opportunities in the lab!