Category Archives: Conservation of Freshwater Fishes

Freshwater fishes are among the most imperiled groups globally with rates of decline comparable to declines in tropical rainforest species. Research in the PoeschLab focuses on developing a better understanding of the mechanisms for the decline of freshwater organisms. This research has four main themes, including: 1) threats to freshwater species at risk, 2) stream augmentation and hydrologic alteration, 3) climate change impacts to freshwater fishes, and 4) the spread and impact of invasive species. To achieve our research goals we utilize a variety of expertise in the PoeschLab and the University of Alberta. This includes expertise in: movement ecology and telemetry, assessing foodwebs using stable isotope analysis, population genetics and environmental DNA (eDNA) and morphology and swim performance.

Theis, S.*, Ruppert, J. L. W. and M. S. Poesch. (2023) Coarse woody habitat use by local fish species and structural integrity of enhancements over time in a shallow northern boreal lake assessed in a Bayesian modeling approach. Ecological Solutions and Evidence 4(2): e12200.

Abstract:

  1. The introduction of coarse woody habitat has been a widely adopted management practice for restoring and enhancing freshwater aquatic ecosystems. Although responses of aquatic fish and invertebrate communities have largely been documented for lotic systems, benefits for lentic ecosystems have been mostly unevaluated.
  2. We tested the responses of fish populations to coarse woody habitat structures through a Bayesian modeling approach in a northern boreal lake in Alberta, Canada by enhancing a stretch of littoral zone with low structural complexity through introduction of coarse wood bundles and whole tree structures. The study site was split into three treatments, a Spaced treatment (structures 30 m apart), a Clustered treatment (structures 15 m apart), and an unaltered area (Control).
  3. Catch per unit effort and Catch per unit area data were collected over 2 years and posterior model predictions showed an increase in habitat use of the enhanced areas by spottail shiner – Notropis hudsonius; northern pike – Esox lucius; white sucker – Catostomus commersonii; brook stickleback – Culaea inconstans. No probable effect on overall fish condition, measured in Relative Weight, was linked to the enhancements.
  4. Across the two-year study, wood bundles degraded faster compared to the whole tree drops, coinciding with leveling off catch per unit effort and catch per unit area predictions near wood bundles, although catch predictions increased near the whole tree structures. Structural degradation set in as early as 1 week post construction for wood bundles and was mostly related to anchoring aspects.
  5. Results from our study provide evidence for the benefits provided by coarse woody habitat within northern boreal lake systems.  They furthermore highlight the short-lived nature of wood bundles built with biodegradable substances.  Methodologically our results offer evidence on the feasibility and utility of predictive modeling frameworks in addressing pseudoreplication and providing informative value for ecological studies.

Citation: Theis, S., Ruppert, J. L. W. and M. S. Poesch. (2023) Coarse woody habitat use by local fish species and structural integrity of enhancements over time in a shallow northern boreal lake assessed in a Bayesian modeling approach. Ecological Solutions and Evidence 4(2): e12200.

Also Read:

Theis, S.*, Ruppert, J.*, Shirton, J.* and M.S. Poesch (2022) Measuring beta diversity components and beneficial effects of coarse woody habitat introduction on invertebrate and macrophyte communities in a shallow northern boreal lake: implications for offsetting. Aquatic Ecology 56: 793-814.

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

Theis, S.*  Castellanos D.A., Hamann A. and M.S. Poesch. (2023) Small-bodied fish species from western United States will be under severe water stress by 2040. Conservation Science and Practice: e12856.

Abstract:

Human need to appropriate freshwater in combination with climate change has intensified the rapid decline in freshwater biodiversity. Based onUsing census data, threat assessments, life history traits, as well as projections for anticipated water stress, we carried out a risk assessment for 216 currently imperiled freshwater species in the United States. , the The results suggest that Southwestern, and the Rocky Mountains, regions willwere predicted to experience the highest increase in future water stress for 2040 in 41 minor watersheds. Resident-small species in the Southwest, found in single locations (21.6%) or on local level highly localized (62.2%), were listed as endangered (n = 37) and are predicted to experience severe water stress increases by Endangered species in the Rocky Mountains (n = 9), were found on a single basins or local level had localized distributions (33.3%), and had exhibiting predominantly potamodromous  behaviour (66.7%). Furthermore, many endangered species in key regions lack life-history data (41%). Our results highlight predict patterns of imperilment associated with life history traits and distributions, but that were unrelated to overall fish biodiversity or biodiversity hotspots. that assessing species using The research therefore highlights that biodiversity as an indicators may not be useful to prioritize conservation efforts for identifying future impacts to imperiled species, since many regions undergoing high water stress did not coincide with biodiversity hotspots. Keywords: Climate Change; Water Stress; Biodiversity; Preservation.

Citation: Theis S., Castellanos-Acuna D., Hamman A. and M. S. Poesch. (2023) Small-bodied fish species from western United States will be under severe water stress by 2040. Conservation Science and Practice: e12856.

Also Read:

Miller, M., Stevens, C. and M. S. Poesch. (In Press). Effectiveness of Spawning Substrate Enhancement for Adfluvial Fish in a Regulated Sub-Arctic River. River Research and Applications.

*Lab members: Sebastian Theis and Mark Poesch. Check out opportunities in the lab!

Theis, S.*  Castellanos D.A., Hamann A. and M.S. Poesch. (2022) Exploring the potential role of habitat banks in preserving freshwater biodiversity and imperiled species in the United States. Biological Conservation 273: 109700.

Abstract:

Habitat banking, a conservation approach to offset habitat loss, has been widely accepted and implemented in the United States, especially for the protection of freshwater ecosystems. The potential adequacy of the habitat banking approach has, however, not yet been formally quantified in the context of its underlying framework and policies. Using a gap analysis approach, we test the current adequacy and future potential of habitat banking for 2313 approved and 552 pending banks in the United States. In the analysis, we consider water stress due to projected climate change, freshwater diversity, imperiled species, and human population growth, among other factors. The results show that the highest conservation urgency was assigned to states in the Southwest with high levels of species imperilment and large increases in anticipated water stress. The banking network covers most of the freshwater biodiversity hotspots in the East and Southeast. Land ownership is a potential driver for the low bank density in western states, with large proportions of land being owned and managed through federal agencies and only 58 banks situated on federal land. While the banking network in the United States is one of the most developed on a global level, gaps and priority areas can be clearly identified to strengthen the current network and its role in preserving freshwater habitat and diversity. Keywords: Offsetting; Conservation policy; Biodiversity market; Preservation.

Citation: Theis, S.  Castellanos D.A., Hamann A. and M.S. Poesch. (2022) Exploring the potential role of habitat banks in preserving freshwater biodiversity and imperiled species in the United States. Biological Conservation 273: 10970.

Also Read:

Theis, S.* and M. S. Poesch. (In Press).  Mitigation bank applications for freshwater systems: Control mechanisms, project complexity, and caveats PLOS One.

 

*Lab members: Sebastian Theis and Mark Poesch. Check out opportunities in the lab!

Three new articles on habitat banking and offsetting accepted! Check them out!

Citation: Theis, S.  and M.S. Poesch. (2022) Assessing conservation and mitigation banking practices and associated gains and losses in the United States. Sustainability.

Citation: Theis, S.  Castellanos D.A., Hamann A. and M.S. Poesch. (2022) Exploring the potential role of habitat banks in preserving freshwater biodiversity and imperiled species in the United States. Biological Conservation.

Citation: Theis, S.  Koops, M. and M.S. Poesch. (In Press) A meta-analysis on the effectiveness of offsetting strategies for harm to freshwater fishes. Environmental Management.

Theis, S.*  Koops, M. and M.S. Poesch. (2022) A meta-analysis on the effectiveness of offsetting strategies for harm to freshwater fishes. Environmental Management 70(5): 793-807.

Abstract:

Offsetting aims to compensate for negative impacts due to authorized anthropogenic impacts. While anchored into legislation through extensive frameworks across many countries, residual or chronic impacts can occur after offset establishment for example because of the ephemeral timescale of some projects. Advice and best practice on how to approach these impacts is rare. To address this, we reviewed 30 projects based on a systematic review and meta-analysis in freshwater ecosystems dealing with residual or long-term negative impacts to provide application advice for the three main identified approaches of: habitat creation, habitat restoration and biological and chemical manipulation. Project information was obtained from scientific databases and grey literature through Boolean search terms and web-scraping. Habitat creation projects, mainly targeting salmonids, had a pooled effect size of 0.8 and offsetting ratios of 1:5 with high biomass increases of over 1.4x compared to pre-establishment, associated with them. Habitat restoration projects targeted a wide range of species and communities with a pooled effect size of 0.66, offset ratios ranging from 1:1.2 to 1:4.6, and biomass increases generally > 1x compared to pre-restoration. Biological manipulation had the lowest effect size (0.51) with stocking efforts being highly variable both in terms of biomass benefits and project outcomes pointing towards stocking being mostly applicable in cases of direct fish harm not related to environmental degradation or habitat loss. Many projects targeted salmonid species and application for a wider range of species needs to be further assessed. We conclude that 1) all three assessed approaches have a potential application use for offsetting Residual or Chronic Harm with approach specific caveats. 2) time to record first benefits required one to two years with time lags needing to be accounted for in the implementation and monitoring process, 3) monitoring timeframes of more than four years and conducting pre-assessments increased projects success significantly. Keywords: Offsetting; Conservation policy; Biodiversity market; Preservation.

Citation: Theis, S.  Koops, M. and M.S. Poesch. (2022) A meta-analysis on the effectiveness of offsetting strategies for harm to freshwater fishes. Environmental Management 70(5): 793-807.

Also Read:

Theis S.*, and M.S. Poesch (2022) Current capacity, bottlenecks, and future projections for offsetting habitat loss using mitigation and conservation banking in the United States. Journal for Nature Conservation 67:126159.

*Lab members: Sebastian Theis and Mark Poesch. Check out opportunities in the lab!

Theis S.*, and M.S. Poesch (2022) Assessing conservation and mitigation banking practices and associated gains and losses in the United States. Sustainability 14: 6652.

Abstract:

Conservation and mitigation banks allow proponents to buy credits to offset negative residual impacts of development projects with the goal of No net loss (NNL) in ecosystem function and habitat area. However, little is known about the extend to which bank transactions achieve NNL. We synthesized and reviewed 12756 transactions in the United States as to meeting area and ecological equivalence (n = 4331) between approved negative impact and offset. While most transactions provided an offset equal or greater in area than the impacted area, approximately one quarter of transactions, especially targeting wetlands, did not meet ecological equivalence between impact and offset. Missing ecological equivalence was often due to the significantly increasing use of preservation, enhancement, and rehabilitation over creating new ecosystems through establishment and re-establishment. Stream transactions seldom added new ecosystem area through creation but mainly used rehabilitation to add offset benefits, in many cases leading to net loss of area. Our results suggest that best practice guidance on habitat creation as well as incentivization of habitat creation must increase in the future to avoid net loss trough bank transactions and meet the ever-accelerating global changes in land-use and the increase pressure of climate change. Keywords: Offsetting; Conservation policy; Biodiversity market; Preservation.

Citation: Theis, S.  and M.S. Poesch. (2022) Assessing conservation and mitigation banking practices and associated gains and losses in the United States. Sustainability 14: 6652.

Also Read:

Ruppert, J.L.W.*, Hogg, J., and M.S. Poesch. (2018) Community assembly and the sustainability of habitat offsetting targets in the first compensation lake in the oil sands region in Alberta, Canada. Biological Conservation 219: 138-146.

*Lab members: Sebastian Theis and Mark Poesch. Check out opportunities in the lab!

Theis, S. (2022) Offsetting approved harmful anthropogenic impacts in the 21st century – Insights into global offsetting practices, habitat banking as an alternative offsetting mechanism and application of habitat enhancement in northern boreal lake systems.

Thesis Title: Offsetting approved harmful anthropogenic impacts in the 21st century – Insights into global offsetting practices, habitat banking as an alternative offsetting mechanism and application of habitat enhancement in northern boreal lake systems.

Author: Sebastian Theis

Abstract

Land-use change via human development is a major driver of biodiversity and habitat area loss and ecosystem function impairment. To reduce these impacts, billions of dollars are spent on environmental offsets, aimed to compensate for authorized negative impacts. Studies evaluating offset project effectiveness and individual mechanisms, remain rare.

Chapter 2 aimed to address the persistent questions of whether high project compliance is synonymous with high functional success as well as how to address residual or chronic impacts in aquatic ecosystems which can occur after offset establishment, for example because of the ephemeral timescale of some projects through a systematic review process and meta-analysis. While compliance and function were related to each other, a high compliance score did not guarantee a higher degree of function. However, function did improve with larger projects, specifically when projects targeted productivity or specific habitat features, and when multiple complementary management targets were in place. Altogether these relationships highlight specific ecological processes that may help improve offsetting outcomes for the conservation of habitat and biodiversity. The meta-analysis for offsetting residual or chronic impacts yielded three main approaches; habitat creation; restoration and enhancement and biological manipulation. Habitat creation projects, mainly targeting salmonids, with a high pooled effect size (0.8) and biomass increase (x1.4) needs to be explored for other species had a pooled effect size. Habitat restoration projects targeted a wide range of species and communities with a pooled effect size of 0.66, and intermediate biomass increases (>1x). Biological manipulation had the lowest effect size (0.51) with effort outcomes being highly variable.

Conservation and mitigation banks are widely used alternative mechanisms to traditional offsetting to compensate for unavoidable negative environmental impacts from development. In Chapter 3 we utilized publicly available banking data from for the United States to test whether area ratio requirements were met as well as how well ecological equivalency was achieved and to model current and future bank reserves through a predictive modeling framework. We conclude that most bank transactions using Preservation, Enhancement, and Re-establishment targeting wetlands, species, or multiple Mitigation-Targets met No Net Loss requirements on a ratio base. Wetland transactions, making up most of all assessed transactions (n = 10628), still missed matching appropriate impact to offset types in 25% of all cases, mainly due to Preservation not leading to any additional habitat area gain.  While the Preservation of wetlands and the Rehabilitation of streams can provide a multitude of benefits, both practices need to be revised on an ecological level to bridge the gap between Not Net Loss based on credit and area yield ratios and ecological equivalence. Future predictions indicate a decrease in available reserves for banks targeting wetlands or multiple ecosystems, with potential bottlenecks relating to large reserves being limited to the Southeast and release schedules not catching up to the current and anticipated demand. Banks targeting species or streams are predicted to meet future demand, with species banks (conservation banks) following a different legislative and operational approach based on the listing of endangered species. Most current reserves for all four bank types are restricted to very few service areas with around one-third of all bank areas still awaiting release, limiting their availability on a broader scale.

Chapter 4 focussed on the introduction of coarse woody habitat in a northern boreal lake and responses of aquatic fish, invertebrate and macrophyte communities through a Bayesian modeling approach and the use of changes in beta diversity components over time. Catch data was collected over 2 years and posterior model predictions showed an increase in habitat use of the enhanced areas by resident fish (spottail shiner – Notropis hudsonius; northern pike – Esox lucius; white sucker – Catostomus commersonii; brook stickleback – Culaea inconstans), while no probable effect on overall fish health, measured in Relative Weight, was linked to the enhancements. Enhancement structures featured increased macrophyte and invertebrate richness and biomass compared to reference sites and pre-treatment assessments over the course of three years. Enhanced sites also retained improved richness (macrophytes), diversity (macroinvertebrates) and biomass (both), despite structural integrity loss of enhancements as early as 1 week post construction.

 

Pallard, J. (2022) Assessing the effects of non-native salmonids on Bull Trout (Salvelinus confluentus) in Alberta’s Rocky Mountain foothills.

Thesis Title:Assessing the effects of non-native salmonids on Bull Trout (Salvelinus confluentus) in Alberta’s Rocky Mountain foothills.

Author: Jacqueline Pallard

Abstract

The rapid decline in global biodiversity threatens the natural resources, food security, health, and livelihoods of current and future generations. Anthropogenic activities, including the introduction of non-native species, habitat fragmentation and alteration, and resource extraction, have exacerbated this decline. One such imperiled species are Bull Trout (Salvelinus confluentus), which have exhibited significant declines throughout their range and are expected to decline by >30% over the next 21 years in Alberta. While their decline is attributed to a myriad of threats, the degree to which non-native fishes contribute to their decline is uncertain. The objective of my thesis was to investigate the effects of Brook Trout (Salvelinus fontinalis) and Brown Trout (Salmo trutta), two non-native salmonids, on the habitat use and dietary niche of Bull Trout. To address the habitat component, I developed a multi-species N-mixture model using in-stream and land use derived characteristics to assess how Brook Trout and Brown Trout affect Bull Trout abundance in relation to habitat factors. I determined that Brook Trout negatively affect Bull Trout abundance when streams are <11°C and lack habitat complexity. Interactions between Brown Trout and Bull Trout are less certain, but larger, lower elevation streams are likely to see reductions in Bull Trout abundance where Brown Trout invasion is present and likely to occur. To address the dietary component, I employed stable isotope analysis to investigate how Brook Trout and Brown Trout interact with the dietary niche of Bull Trout. I determined that Bull Trout in sympatry with both Brook Trout and Brown Trout undergo a niche shift and are displaced from terrestrial-based resources. Furthermore, potential for competitive exclusion exists when resources are low given all species exhibit a high degree of niche overlap (>80%) when in sympatry and the amount of niche overlap does not decrease between allopatry and sympatry. The findings of my thesis suggest that both Brook Trout and Brown Trout interfere with the resource use of Bull Trout, on multiple levels, and provides practical guidelines for limiting future declines.