Connect Knowledge with Action

CVC hosts an annual Research Colloquium, with the theme Connecting Knowledge with Action. We invite students, professors, and environmental professionals to join us to share and learn about the research that is being carried out in the Credit River Watershed.

Our aim is to facilitate

  • The incorporation of findings from research in our jurisdiction into CVC’s work
  • Enable networking and mentoring
  • Help to build and strengthen collaborations,
  • Provide an opportunity for direct feedback from applied practitioners to researchers

We welcome attendance from all members of our research community. The event is an opportunity to learn more about the watershed and what is happening in it. The program includes presentations from both external researchers and CVC staff, as well as opportunities for networking.

Previous Events

2019 Research Colloquium Program

Jim Bogart, University of Guelph

Unisexual Salamanders in Hilton Falls

Unisexual Ambystoma are the oldest known unisexual vertebrates and comprise a lineage of eastern North American all female salamanders that reproduce by stealing sperm from as many as five normally bisexual congeneric species. The sperm may be used to only stimulate egg development by gynogenesis but can be incorporated in the zygote to elevate the ploidy level or to replace one of the female’s haploid genomes. This flexible and unique reproductive system, termed kleptogenesis, is investigated using a microsatellite examination of 988 offspring from 14 unisexual mothers. All mothers produced clonal as well as ploidy-elevated offspring. Genome replacement and multiple paternity are confirmed for the first time in unisexual Ambystoma at Hilton Falls Conservation area. Microsatellite mutations were found in all five microsatellite loci and the estimated microsatellite mutation rate varied by locus and by genome. Clonal variation is attributed to the inclusion of sperm donors’ haploid genomes for ploidy elevation, genome replacement, mutations, and natural selection.

Junaid Khan & Chris Lovell, York University

Understanding the impacts of European Fire Ants (EFA’s; Myrmica rubra) on anuran populations in wetland habitats

There is a paucity of data on how invasive species may impact anuran populations (Beebee and Griffiths, 2005; Gibbon et al., 2000; Riley et al., 2005).  A prolific invasive species – a small (approx. 3mm) red ant native to the Palearctic regions of Europe – Myrmica rubra (GISD, 2018) is largely unstudied for its potential impacts on anurans. The species was first identified in the Credit River watershed in 2001. Our study created a framework based on anuran and M. rubra life history traits to identify any overlap in niche, and potential interspecies competition. We quantified M. rubra abundance at seven CVC wetlands that also had between 12 and 15 years of anuran trends from Frog Watch efforts. Using presence/absence trends for six anuran species, we predicted that wetlands with high M. rubra abundance would show fewer years of a species being present compared to wetlands with low M. rubra abundance. The presence of one of the seven tested anuran species, Spring Peeper (Pseudacris crucifer) was negatively associated with M. rubra abundance (p = 0.002).  A follow-up in 2018 attempted to find empirical evidence of interactions between American Toad (Bufo americanus) and M. rubra at Rattray Marsh. Although no direct interactions were found, more surveys are needed to determine the anuran-ant interspecies interactions within CVC wetlands.

Kirsten Burling, Bird Studies Canada

2016-2019 Great Lakes Marsh Monitoring Program Amphibian Survey of Rattray Marsh and Turtle Creek

In 2016 Kirsten Burling began Bird Studies Canada’s Great Lakes Marsh Monitoring Program’s amphibian survey which is night monitoring of calling frogs and toads. Three stations were set up:  Station A on Turtle Creek in Jack Darling Memorial Park, Stations B and C on the knoll in Rattray Marsh Conservation Area, with B facing southward and C facing northward. The monitoring protocol for the programme was followed, involving three visits through spring and early summer to record early, mid and late breeding anurans.  Credit Valley Conservation added Stonehaven Creek Bridge to the surveys, as Spring Peepers had been reported from this forested area. Over the four years of monitoring there was no evidence of Pickerel, Mink or Chorus Frog. A possible Wood Frog and possible Spring Peeper were heard the first year. Northern Leopard Frog was heard at all three marsh stations but not every year. American Toad and Green Frog were present at all three marsh stations every year. In the last two years, American Toad has been heard from the Stonehaven Creek Bridge. Finally, in 2919 a Gray Tree Frog was heard high on the hill between Turtle Creek and Rattray Marsh.  Recommendations are made with regard to controlling phragmites at Stations S & B; bringing a halt to park refuse dumping into Turtle Creek;  maintaining a corridor between Birchwood Park, Jack Darling & Rattray;  reducing trail toad mortality with signage and education;  maintaining access to the knoll lookout & boardwalk to Stations B & C for required monitoring April, May & June; and controlling water levels, especially after amphibian eggs are laid.

Mitchell Bonney, University of Toronto Mississauga

Insight on long-term forest change in the Credit Valley Watershed: Connecting satellites and field data.

In the Credit Valley Watershed, which has been under environmental pressure due to urbanization since the mid-1900s, protecting and maintaining the health of remaining forest communities is vitally important. To better understand what might influence these forests in the future, it is crucial to understand how past policies, actions and events may have influenced forests in the past. The Landsat satellite archive is uniquely positioned to monitor past changes across the entire watershed since 1972 at a spatial resolution capable of quantifying change even in small forest stands. However, changes observed by stacks of these satellite images through time are quantified as spectral reflectance variables. These variables are not ideal for conservation agencies and other organizations that make decisions and create policies based on information related to on-the-ground variables such as canopy cover and forest productivity. To combat this issue and through collaboration with Credit Valley Conservation, we have spent the last two summers collecting field data, including hemispherical photographs, forest inventories and tree cores, at dozens of forest sites across the watershed. These data are being compared with Landsat time-series data over the same locations to understand the relationship between on-the-ground variables and satellite reflectance. With these connections we can transform our Landsat time-series data from long-term change in reflectance to change in, for example, canopy cover. This transformation allows our dataset to be used with confidence in the decision and policymaking process.

Milena Rosenfield, University of Guelph

Estimates of ecosystem services in mosaic landscapes in Southern Ontario: influence of land cover and plant traits

Land use intensity and plant functional traits associated with ecosystem functions can influence the functioning of ecosystems and the potential to provide goods and services beneficial to humans. In mosaic landscapes, such as those encompassing agricultural, urban and natural areas, the potential of an ecosystem to provide a broad range of ecosystem services is vital to human well-being. The University of Guelph has been working with the CVC on several projects to explore the provision of multiple ecosystem services by natural ecosystems in the Credit River Watershed and evaluate the effect of landscape (land use) and plant characteristics (functional traits) on these services. A recently published study analyzed how landscape variables affect community assembly patterns, finding that landscape variables result in significant trait-divergence assembly patterns in different spatial scales. This study discusses the implications of trait divergence as well as the mechanisms through which landscape metrics might be responsible for these patterns. Our current project has two main objectives: the first is to assess the provision of multiple ecosystem services by different natural ecosystems (forests, riparian forests and wetlands) and to evaluate the impact of surrounding land cover on these ecosystem services. The second objective is to identify indicators for ecosystem services in forests using plant functional traits. This study highlights the importance of conserving natural ecosystems and preserving the provision of services that benefit human well-being, with implications for landscape management.

Hossam Abdel Moniem, University of Toronto Mississauga

Modeling and evaluating connectivity networks for the Credit valley watershed

The Provincial Policy Statement 2014 mandates planning and development of natural heritage systems in order to maintain, restore, or improve biodiversity and connectivity of natural heritage systems. Credit Valley Conservation authority (CVC) works with municipalities to develop and manage natural heritage systems within the Credit river watershed. Therefore, there is an important demand to modeling connectivity and evaluating the importance of natural heritage features within the CVC jurisdiction to optimize and prioritize their conservation efforts. In collaboration with the CVC, we used a Circuit Theory approach to model a wall-to-wall, high-resolution current density map to characterize the important connectivity pathways that facilitate the flow of biodiversity in the CVC landscape. We then analyzed the importance of each natural heritage feature for maintaining the connectivity network using a weighted least cost path, and four critical Euclidian dispersal thresholds identified by the CVC with insight into their biodiversity data. Our results illustrate the importance of natural heritage features within the CVC jurisdiction in maintaining the connectivity network within the Credit river watershed, which has been underestimated when modeled, previously, at the provincial scale. The implementation of this approach contributes to the CVC efforts towards prioritizing conservation decisions.

Zoe Bedford & Monique Dosanjh, University of Toronto Mississauga

Mapping Spatial and Temporal Trends in Lake Bathymetry in the Credit Valley Watershed Using Landsat Images

Bathymetry is the study and measurement of the depth of water bodies, and is an essential parameter to understand trends in the water volume and water variability in lakes. Accurate and detailed knowledge of lake depth in urban and suburban landscapes is important for a variety of applications including managing and maintaining aquatic ecosystem functioning in the context of rapid urbanization and climate change. Remote sensing technologies have been demonstrated to be time efficient and cost-effective in deriving lake bathymetry data and monitoring the spatial and temporal status of lake depth through their large geographical coverage and long history of image acquisition. One method is the SPEAR Relative Water Depth tool, an algorithm created to estimate the relative and absolute depth of water bodies from optical satellite imagery. Through the use of Landsat 8 imagery and the SPEAR Relative Water Depth tool in ENVI, this study derived the absolute depth for the lakes in the Credit Valley Watershed, and evaluated the accuracy of satellite-derived depth using ground depth data collected from three lakes. In addition, this study also investigated the ability of satellite-derived bathymetry to monitor spatial and temporal changes in lake depth between a wet and a dry year. Our work not only gains a comprehensive view of the current bathymetry of lakes in the Credit Valley Watershed, but also provides insights on how lakes have changed annually.

Meagan Kindree, University of Toronto Scarborough

Interactive Effects of Climate Change and Invasive Species

Climate change is a principal threat to freshwater biodiversity and to the structure and functioning of ecosystems. Freshwater fishes are particularly vulnerable to climate change due to their ectothermy and constrained dispersal ability within dendritic networks. Global climate change will alter thermal habitat availability for native and non-native invasive species, leading to changes in distribution and, potentially, negative impacts on ecosystem function. Synergies with invasive species, could amplify the effects of climate change on ecosystems and their communities. Native White Sucker (Catostomus commersonii) and invasive Round Goby (Neogobius melanostomus) were chosen as candidate species to examine how increases in temperature may influence native fish’s distribution and competition. This research completed in the Credit River has two main objectives. Firstly, to examine the response of these native and invasive fishes to increasing water temperature by measuring their agitation temperature and critical thermal maximum (CtMax) to predict their potential future interactions under a warming climate. Secondarily, to examine the trophic level and diet breadth of a native species when an invader of a similar fundamental niche is present. In collaboration with Credit Valley Conservation fish crews, I investigated the CtMAx of the two species to quantify differences in thermal tolerance in a natural system. Preliminary analysis suggests that CtMax and agitation temperature are significantly higher in Round Goby. In addition, the location along the river gradient is a significant driver of CtMax, suggesting some level of phenotypic plasticity in thermal tolerance of both species.

Lauren Lawson, University of Toronto

Road salt as a stressor to aquatic species at risk in Southern Ontario

The Golden Horseshoe region of southern Ontario is one of the most rapidly growing areas in North America, and with this growth comes an increase in impermeable surfaces including roads, parking lots, and sidewalks. In winter climates particularly, increases in road density leads to increases in the use of road salt. Road salt then enters waterbodies and groundwater through road runoff leading to increases in water salinity, with some locations having winter chloride concentrations comparable to brackish estuaries and even some concentrations similar to seawater. Our results show influxes of chloride in winter can persist year-round and lead to chronically high chloride concentrations, even in summertime when more natural background levels might be expected. Elevated chloride concentrations can be lethal for freshwater organisms and have been found to alter organismal behaviour and community dynamics at sublethal concentrations. As the distribution of many aquatic species at risk in Canada is concentrated in southern Ontario, an area with high application rates of road salt, increasingly elevated levels of chloride may represent a significant factor contributing to the decline of various species at risk. The initial phase of our research seeks to determine if chloride is contributing to the decline of Redside Dace. To accomplish this, we are studying exposure of Redside Dace to chloride in currently known sites as well as historic sites where extirpation is believed to have occurred.

Anna Marie O’Brien, University of Toronto

Urban runoff and the evolutionary ecology of aquatic plant-microbiome interactions

Plant-microbiome interactions are ubiquitous and provide critical support of plant growth both in natural and agricultural systems. Urbanization of landscapes brings previously un-encountered stressors, from urban heat islands to chemical-laden surface runoff, and such novelty may perturb plant-microbe interactions. Runoff contaminants disproportionately affect freshwater species, so we focus on a floating plant Lemna minor (duckweed) and its microbiome. Duckweed is tiny (fronds 2-5 mm) and reproduces rapidly (clonal generations in 3 days), making it highly amenable to experimentation. Duckweed hosts a mutualistic and diverse microbiome, of which many species can be lab-cultured, facilitating microbiome manipulation. We found that contaminant stressors (metals, salt, and anti-corrosives), and the origin of duckweed and its microbiome from across the Greater Toronto Area (including the Credit Valley watershed) can interactively alter plant traits. In fact, microbes favor biotransformation of some runoff contaminants to less stressful or growth-promoting compounds, and urban duckweed better tolerate chemical inputs. In progress work will test whether global change stressors in concert (CO2, temperature, and road runoff) predictably affect plant microbial communities.

Rosalind Murray, University of Toronto Mississauga

The effect of deicing road salt on dragonfly growth, survival and performance

The salinization of freshwater habitats is causing decreases in aquatic biodiversity on a global scale.  Deicing road salt is a major contributor to increased salt pollution in cold climates, particularly in road-adjacent freshwater environments.  Using a mesocosm experimental set up, we investigated the effect of environmentally relevant levels of road salt exposure on larval dragonflies from a CVC stormwater pond.  Dragonfly larvae are important predators in freshwater environments and can shape aquatic communities. Moreover, adult dragonflies prey on human disease vectors (e.g. mosquitoes) and provide an important resource for higher predators such as birds and fish.  Determining how dragonflies persist in the increasing salinity they experience in urban environments can be broadly applied to understanding how increased application of deicing road salt will influence both aquatic and terrestrial communities as a whole. We did not see any difference in growth rate and survival across salt treatments; however, we did find several sub-lethal effects of salt pollution on dragonfly performance.  Salt-exposed dragonfly larvae decreased their foraging rate (consumed fewer mosquitoes) compared to control larvae.  We also observed carryover effects; dragonflies exposed to road salt as larvae were less able to mount an effective immune response as adults.  We suggest that road salt pollution in freshwater habitats is likely impacting organisms in subtle and sub-lethal ways that will accumulate quickly to influence community structure (e.g. more mosquitoes and vulnerable dragonflies) in both aquatic and terrestrial environments.

Chris MacQuarrie, Canadian Forest Service

Update on biological control of the emerald ash borer

A summary of the releases to date of the three species of parasitoids across eastern Canada and an update on research to assess establishment, impact and spread.

Amanda Liczner, York University

Using detection dogs to locate bumble bee nests: Lessons learned

Habitat loss is one of the main threats to bumble bees yet our understanding of bumble bee habitat is limited. This is especially true for the nesting habitat of bumble bees. The difficulty in locating bumble bee nests, which are often underground, may be contributing to our lack of knowledge of this critical resource. To address this important knowledge gap, we deployed detection dogs that were trained on the scent of bumble bee nests to three sites: Terra Cotta and Silver Creek Conservation Area and Scotsdale Farm. Although the dogs can detect the scent of bumble bee nests there were a number of challenges that may limit the applicability of this technique. These challenges include: humans are required to find confirmed wild nests, the search strategy, scent differences between nests, and site considerations.

Kayla Mundy-Heisz, University of Guelph

A comparison of bumble bees in farms and natural areas

Bumble bees (Bombus sp.) are generalist pollinators supporting a wide array of flora within the Northern Hemisphere. These bees also contribute to agricultural production of many fruits, berries and vegetables. Bumble bees are facing a myriad of risks which vary in intensity of interaction across space and time, including habitat loss, disease, invasive species, climate change, and pesticides. To understand the impact of farming on bumble bees, particularly queens, field studies comparing natural areas and farms in South Central Ontario were conducted over the past two years. Caught bumble bee queens were identified and marked before being released at the end of each sampling session. The abundance and diversity of bumble bee queens within natural areas and farms was compared. Further, the behaviour of the queen at the time of capture was recorded to examine any behavioural differences between natural areas and farms. If queens were foraging, the flower being used was recorded, allowing for comparison of foraging choice between natural areas and farms. This work is crucial to determine the number and diversity of bumble bee queens that may be exposed to pesticides from fields and if farms can also be used to promote the conservation of a wide range of bumble bee diversity.

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