Movement of an imperiled esocid fish in an agricultural drain

Animal movement is increasingly affected by human alterations to habitat and climate change. In wetland systems, widespread hydrologic alterations from agriculture have changed the shape, function, and stability of shallow streams and wetland habitats. These changes in habitat quality and quantity may be especially consequential for freshwater fishes such as Grass Pickerel (Esox americanus vermiculatus), a small predatory fish found in disjunct populations across southern Ontario and listed as Special Concern under Canada's Species at Risk Act. To characterize Grass Pickerel movement response to stream-channel alterations, Fisheries and Oceans Canada implemented a tracking study to monitor the movements of a Grass Pickerel population in an agricultural drain on the Niagara Peninsula (Ontario, Canada). From 2009 to 2013, 2007 Grass Pickerel were tagged and tracked in the 37.3 km2 Beaver Creek watershed using a combination of mark-recapture surveys and eight fully automated passive integrated transponder tag antennas. Most individuals moved within 500 m (i.e., stationary fish) while 16% of the fish moved > 500 m (i.e., mobile fish), with a maximum median movement distance of 1.89 km and a maximum movement distance of 13.5 km (a long-tail distribution). Most movements occurred near the largest confluence where only a few were long-distance upstream or downstream movements. Mobile fish were larger than their stationary counterparts. Grass Pickerel in sites with higher abundance had more mobile fish, implying potential density dependence. Our results highlight that, while a long-distance dispersal ability exists in extant Grass Pickerel populations, the current conditions of riverscapes may prevent these dispersals from occurring. For declining Grass Pickerel populations, limitations to their movement ecology may substantially increase the likelihood of local extirpations.

Public opinion on the conflict between the conservation of at-risk species and the extraction of natural resources: The case of caribou in boreal forest

Conflicts between economic development and conservation are increasingly hampering efforts to restore imperiled wildlife populations. Public opinion can influence how these conflicts translate into conservation actions, encouraging stakeholders to express their views through various public channels. The outcome of these campaigns typically remains unknown. Via an online survey, we collected to the opinion of 1000 citizens of Québec, Canada, regarding the ongoing conflict between logging and the conservation of at-risk caribou populations (Rangifer tarandus). We found that people expect conservation actions that are sufficient to recover caribou populations, even if millions of government investment are required and jobs are lost in the process. When respondents learned that academic caribou researchers indicated that the two management strategies being studied by government would be insufficient for population recovery, one-third withdrew their support for either strategy. Age, gender and education all explain variation in public opinion, but it was the region of residence that most consistently explained variation in opinion. Residents of caribou-inhabited regions were less concerned about caribou conservation and more supportive of forestry than residents of other regions, reflecting regional differences in expected economic impacts of conservation, not negative interactions with caribou. In fact, most people supported strong conservation actions for the recovery of caribou populations, regardless of their socio-demographics. Our analysis provides general insights into how public opinion on the trade-off between conservation and economy is influenced by socio-demographics and scientific conclusions. We found that current government conservation actions (or lack thereof) are not in line with mainstream public opinion. Moreover, we show that making species at-risk lists does not ensure that the species will benefit from strong conservation actions without lengthy delays, even for a high-profile, flagship species like caribou. This observation echoes concerns about the fate of less charismatic, at-risk species, and thus about future biodiversity conservation efforts.

Cryogenic storage increases the longevity of butternut (Juglans cinerea, L.) seed embryogenic axes

Butternut (Juglans cinerea L.), a species listed as endangered, is currently undergoing rapid decline due to habitat loss and the introduction of Ophiognomonia clavigignenti-juglandacearum, a non-native pathogen causing butternut canker. The decline of butternut has led to the development of cryobiological methods for the ex-situ conservation of the species since viability is not maintained using conventional methods. In this study, we assess the survivability and growth of butternut embryogenic axes into plantlets after 7 years of cryopreservation. Results show that cryopreservation is a highly effective method for the long-term storage of embryogenic axes since both survival and subsequent acclimatization into plantlets was successful with an average of 76% survival and 71% acclimatization, respectively. These results surpass the actual duration viability for non-cryogenic storage of butternut seed and we hope that future testing will result in longer term success of this cryobiological method and provide much needed germplasm for future restoration.

Freshwater mussels in an impacted watershed: Influences of pollution from point and non-point sources

The Grand River watershed in a densely populated region of Ontario supports one of the richest assemblages of freshwater mussels in Canada. However, water quality in this watershed is influenced by urban development, agriculture, and industry. Mussel populations and water chemistry in the lower Grand River and the Boston Creek tributary were evaluated to determine whether point sources of pollution such as discharges of domestic wastewater and industrial effluent, and non-point sources of pollution are affecting mussel distribution and population structure. Semi-quantitative population surveys conducted at 9 study sites identified 20 mussel species, including 3 Species at Risk. Mussel abundance (34-160 mussels/search hour) and species richness indicated that mussel populations in the lower Grand River watershed are continuing to recover from historical lows reported in the 1970s. However, changes in populations at some sites were consistent with altered water chemistry. Most notable was that the three most abundant mussel species in the Boston Creek tributary downstream of a gypsum plant discharge were significantly smaller in length than those upstream of this site. The water chemistry in this habitat was characterized by elevated conductivity (∼2000 μS/cm) and calcium (∼500 mg/L), as well as concentrations of sulfate (∼1000 mg/L) that can be toxic to freshwater mussels. In the Grand River downstream of the confluence with Boston Creek, there tended to be (p > 0.05) fewer mussels (mean 34 ± 20/search h) compared to upstream (mean 67 ± 15/search h) and this corresponded to altered water chemistry, including elevated sulfate (239 mg/L) downstream of the confluence relative to upstream (58 mg/L). These data indicate that chronic exposures to high levels of major ions is likely driving changes to mussel population structure. In addition, the discharges of wash water from a gypsum plant may be impacting sensitive biota in the main stem Grand River well beyond the immediate tributary receiving environment.

Agent-based modelling reveals a disproportionate exposure of females and calves to a local increase in shipping and associated noise in an endangered beluga population

Vessel underwater noise (VUN) is one of the main threats to the recovery of the endangered St. Lawrence Estuary Beluga population (SLEB). The 1% yearly population decline indicates that the cumulative threats are already beyond sustainable limits for the SLEB. However, a potential threefold increase in shipping traffic is expected within its critical habitat in the coming years resulting from proposed port-industrial projects in the Saguenay River. Current data indicate that SLEB typically use multiple sectors within their summer range, likely leading to differential VUN exposure among individuals. The degree of displacement and spatial mixing among habitats are not yet well understood but can be simulated under different assumptions about movement patterns at the individual and population levels. Here, we propose using an agent-based model (ABM) to explore the biases introduced when estimating exposure to stressors such as VUN, where individual-centric movement patterns and habitat use are derived from different spatial behaviour assumptions. Simulations of the ABM revealed that alternative behavioural assumptions for individual belugas can significantly alter the estimation of instantaneous and cumulative exposure of SLEB to VUN. Our simulations also predicted that with the projected traffic increase in the Saguenay River, the characteristics making it a quiet zone for SLEB within its critical habitat would be nullified. Whereas spending more time in the Saguenay than in the Estuary allows belugas to be exposed to less noise under the current traffic regime, this relationship is reversed under the increased traffic scenario. Considering the importance of the Saguenay for SLEB females and calves, our results support the need to understand its role as a possible acoustic refuge for this endangered population. This underlines the need to understand and describe individual and collective beluga behaviours using the best available data to conduct a thorough acoustic impact assessment concerning future increased traffic.

Prioritizing Beneficial Management Practices for Species at Risk in Agricultural Lands

Agricultural expansion and intensification are major drivers of ecosystem degradation and loss of biodiversity around the world. Countries are relying on protected areas to conserve habitats and prevent species decline, but these are either too few, too small, or too disconnected to capture and protect the needs of species at risk (SAR). Privately owned and managed lands and agricultural producers are increasingly needed to assist with habitat conservation and SAR recovery. Uptake of environmentally beneficial management practices (BMPs) by producers is often hindered by the lack of awareness of the needs of SAR and of the contribution they can make to their habitats, an actual or perceived negative economic and operational impact of the necessary management changes, the fear of losing management control over their land, and mistrust toward public agencies. We present an eight-step model framework that allows agricultural producers to privately determine the potential SAR occurring in a land parcel of interest and to identify and prioritize mutually compatible and outcome-oriented BMPs relevant to these species. In Alberta, Canada, the framework resulted in the development of a confidential self-served online extension tool tailored to a typical farm-level management unit, and to the geographical and ecological context of the operation. We provide a case study using a land parcel from the agricultural region of Alberta to illustrate the model and the associated tool. This novel approach can alleviate producers concerns, promote uptake of BMPs, and foster voluntary stewardship of SAR habitats on privately owned or managed lands.

Mercury exposure to swallows breeding in Canada inferred from feathers grown on breeding and non-breeding grounds

Aerial insectivorous birds such as swallows have been the steepest declining groups of birds in North America over the last 50 years but whether such declines are linked to contaminants has not been examined. We sampled feathers from five species of swallow at multiple locations to assess total mercury [THg] exposure for adults during the non-breeding season, and for juveniles on the breeding grounds. We assessed Hg exposure to juvenile birds in crop- and grass-dominated landscapes to determine if land-use practices influenced feather [THg]. We assayed feathers for stable isotopes (δ²H, δ¹³C, δ¹⁵N) as proxies for relative habitat use and diet to determine their potential influence on feather [THg]. Feather [THg] was highest in adult bank swallows (Riparia riparia) and purple martins (Progne subis) from Saskatchewan and adult cliff swallows (Petrochelidon pyrrhonota) from western regions, indicating differential exposure to Hg on the non-breeding grounds. Juvenile bank, barn (Hirundo rustica) and tree (Tachycineta bicolor) swallows had lower feather [THg] in crop-dominated landscapes than grass-dominated landscapes in Saskatchewan, potentially resulting from lower use of wetland-derived insects due to wetland drainage and intensive agriculture. Feather [THg] was related to juvenile feather stable isotopes for several species, suggesting complex interactions with diet and environmental factors. Many individuals had feather [THg] values >2 µg/g, a threshold at which deleterious effects may occur. Our findings indicate differential Hg exposure among species of swallow, regions and land-uses and highlight the need for additional research to determine dietary and finer-scale land-use impacts on individual species and populations.

Impact of natural resource extraction on thermal properties of wood turtle (Glyptemys insculpta) habitat

One of the main threats to freshwater turtle populations is habitat destruction, which occurs as a result of human activities such as infrastructure development, forestry, aggregate extraction, and agriculture. However, the impacts of these activities on thermoregulatory opportunities for turtles are not well understood. We examined the impacts of forestry and aggregate extraction on thermal characteristics of wood turtle (Glyptemys insculpta) habitat in the Sudbury District, Ontario, by measuring the differences in absolute temperature, thermal landscape structure, and habitat thermal quality among relatively undisturbed sites (N = 2), harvested forestry sites (N = 2), and aggregate pits (N = 2) in 2015. We also tested the potential use of the thermal landscape concept as a predictor of habitat thermal quality. Undisturbed habitats were of higher thermal quality than impacted sites in terms of temperatures experienced in situ by wild wood turtles in their natural home ranges, and never reached temperatures that would be injurious to turtles (i.e., below CT_MIN or above CT_MAX). The undisturbed sites were of lower quality in terms of optimal temperatures (i.e., T_set), and were generally cooler and their temperatures less variable than those in impacted habitats. The thermal landscape concept provided a useful predictor of habitat thermal quality when the influence of time of day was factored into the predictive model. Our data are important to the conservation and management of wood turtles because they provide a preliminary quantification of the thermal impacts of natural resource extraction on the habitat of an endangered species, and can guide the development of mitigation and rehabilitation plans by providing measures of, and targets for, thermal habitat quality.

Economic analysis of threatened species conservation: The case of woodland caribou and oilsands development in Alberta, Canada

Tradeoffs between cost and recovery targets for boreal caribou herds, threatened species in Alberta, Canada, are examined using a dynamic cost minimization model. Unlike most approaches used for minimizing costs of achieving threatened species targets, we incorporate opportunity costs of surface (forests) and subsurface resources (energy) as well as direct costs of conservation (habitat restoration and direct predator control), into a forward looking model of species protection. Opportunity costs of conservation over time are minimized with an explicit target date for meeting species recovery targets; defined as the number of self-sustaining caribou herds, which requires that both habitat and population targets are met by a set date. The model was run under various scenarios including three species recovery criteria, two oil and gas price regimes, and targets for the number of herds to recover from 1 to 12. The derived cost curve follows a typical pattern as costs of recovery per herd increase as the number of herds targeted for recovery increases. The results also show that the opportunity costs for direct predator control are small compared to habitat restoration and protection costs. However, direct predator control is essential for meeting caribou population targets and reducing the risk of extirpation while habitat is recovered over time.

Municipal wastewater treatment plant effluent-induced effects on freshwater mussel populations and the role of mussel refugia in recolonizing an extirpated reach

Global human population and urbanization continually increase the volume of wastewater entering aquatic environments. Despite efforts to treat these effluents, they contribute a diverse suite of substances that enter watersheds at concentrations that have the potential to elicit adverse effects on aquatic organisms. The relationship between wastewater treatment plant (WWTP) effluent exposure and biological responses within aquatic ecosystems remains poorly understood, especially at the population level. To examine the effect of WWTP effluents on sentinel invertebrates, freshwater mussels were assessed in the Grand River, Ontario, in populations associated with the outfall of a major WWTP. This watershed, within the Laurentian Great Lakes basin, has a diverse community of twenty-five species of mussels, including nine Species at Risk, and is representative of many habitats that receive WWTP effluents regionally as well as globally. Surveys were conducted to assess the presence and species richness of freshwater mussels. In total, 55 sites downstream of the WWTP were examined using timed visual searches with one or 2 h of effort spent searching 100 m segments. Although seven species of mussels were found in moderate abundance (mean of 8 mussels per hour of searching across 2 sites) upstream of the WWTP outfall, no live mussels were observed for 7.0 km downstream of the WWTP. Long-term water quality monitoring data indicate that ammonia and nitrite concentrations along with large seasonal declines in diel dissolved oxygen were associated with the extirpation of mussels downstream of the WWTP. The first live mussels found downstream were below the confluence with a major tributary indicating that in addition to an improvement in water quality to a state that enables mussels (and/or their fish hosts) to survive, a nearby mussel refuge may have facilitated the recolonization of the depauperate WWTP-impacted zone.

Reference scenarios for exposure to plant protection products and invertebrate communities in stream mesocosms

Higher tier aquatic risk assessment for plant protection products (PPPs) is often based on pond-like mesocosm studies in which transient and dynamic PPP exposure scenarios as observed in lotic systems are hardly achievable. Thus, the present study presents dynamic PPP exposure scenarios at different time scales under flow-through conditions as typical for streams in agricultural landscapes. The stream mesocosm setup allows testing the influence of spatial gradients of exposure over the length of themesocosms. The use of the fluorescent tracer uranine revealed the hydraulic processes generally underlying peak- and hour-scale exposure scenarios and demonstrated an optimized application technique to achieve stable day-scale exposures. Furthermore, to account for potential reactions of invertebrates to PPP exposures in streams (e.g. avoidance behavior and drift), the present study thus aimed at a comprehensive evaluation on how PPP exposure and the establishment of invertebrates can be advanced within streammesocosm testing. For both, peak- and hour-scale exposure as well as the experiments considering the establishment of invertebrates, the presented compilation of experiments was able to highlight the influence of aquatic macrophyteswithin streammesocosms. Since the field relevance of the higher tier aquatic risk assessment for PPPs relies qualitatively on the presence of potentially sensitive or vulnerable species, those species were especially considered. Thus, the establishment of aquatic invertebrates in nondosed streams was evaluated with respect to (i) the presence of different aquatic macrophytes and (ii) the duration of the pre-experimental period. The present study highlights the beneficial influence of complex-structured macrophytes and prolonged pre-experimental periods on the abundance of invertebrate taxa. Furthermore, population dynamics were evaluated statistically by simulating PPP-related declines of 30, 50 and 70%. Thereby,