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Transferability of object-based rule sets for mapping coastal high marsh habitat among different regions in Georgian Bay, Canada
Full text linkCoastal wetlands of eastern and northern Georgian Bay, Canada provide critical habitat for a variety of biota yet few have been delineated and mapped because of their widespread distribution and remoteness. This is an impediment to conservation efforts aimed at identifying significant habitat in the Laurentian Great Lakes. We propose to address this deficiency by developing an approach that relies on use of high-resolution remote sensing imagery to map wetland habitat. In this study, we use IKONOS satellite imagery to classify coastal high marsh vegetation (seasonally inundated) and assess the transferability of object-based rule sets among different regions in eastern Georgian Bay. We classified 24 wetlands in three separate satellite scenes and developed an object-based approach to map four habitat classes: emergent, meadow/shrub, senescent vegetation and rock. Independent rule sets were created for each scene and applied to the other images to empirically examine transferability at broad spatial scales. For a given habitat feature, the internally derived rule sets based on field data collected from the same scene provided significantly greater accuracy than those derived from a different scene (80.0 and 74.3%, respectively). Although we present a significant effect of ruleset origin on accuracy, the difference in accuracy is minimal at 5.7%. We argue that this should not detract from its transferability on a regional scale. We conclude that locally derived and object-based rule sets developed from IKONOS imagery can successfully classify complex vegetation classes and be applied to different regions without much loss of accuracy. This indicates that large-scale mapping automation may be feasible with images with similar spectral, spatial, contextual, and textural properties. © 2011 Springer Science+Business Media B.V
Effects of landscape variables and season on reference water chemistry of coastal marshes in eastern Georgian Bay
Full text linkWe surveyed 34 marshes in relatively pristine Precambrian Shield catchments in Georgian Bay and related water chemistry to a suite of landscape-level variables, including characteristics of the marsh and its drainage basin. The first landscape principal component (explained 48% of variation) ordered marshes along a gradient with high values corresponding to marshes with large watersheds that contain extensive upstream wetland and that receive relatively high precipitation inputs. This axis was negatively related to specific conductivity, pH, nitrate nitrogen, and SO 42- concentrations and positively related to total phosphorus, colour, suspended solids, ammonia nitrogen, and summer dissolved organic carbon. Stepwise regression models built using catchment- and marsh-level variables explained up to 64% of the variation in water chemistry variables. Average precipitation and snowmelt inputs to the catchments were first to enter the majority of models, alone explaining up to 43% of the variation (in the case of water colour), while drainage area alone explained 44% of the variation in pH. Concentrations of catchment-derived constituents in marshes were highest in spring, reflecting greater loadings from the watersheds, while ionic strength was highest during summer, reflecting increased contributions form other sources (i.e., lake water)
Implications of the Species-Area Relationship on Sampling Effort for Marsh Birds in Southern Ontario
Full text linkCoastal wetlands of southern Ontario are highly fragmented and exist as islands within a primarily urbanized and agricultural matrix. Given the large variation in size of remaining fragments, it is important to determine if species-area relationships exist for wetland birds, so that sampling effort can be adjusted for different sizes of wetlands and to develop appropriate size criteria for conservation. We surveyed marsh birds in 21 coastal wetlands of southern Ontario and found a positive species-area relationship (z-value∈=∈0.076), and a positive relationship between an index of biotic integrity and wetland area. Only the Marsh Wren, Swamp Sparrow, and all obligate wetland bird species combined showed area-sensitive distribution patterns. The number of points required to reveal 80% or 90% of the cumulative species richness for a given wetland varied directly with its size, indicating that sampling effort must be increased to avoid underestimating species richness in large wetlands. For example, one would need to conduct 9 point counts using 50-m radius circular plots to survey 90% of the wetland bird species in a marsh of 50 ha. We recommend conservation of coastal wetlands, regardless of size, because both small and large marshes provide habitat for high-integrity, wetland-dependent bird species. © 2010 Society of Wetland Scientists
Seasonal, Interannual, and Spatial Variability in the Concentrations of Total Suspended Solids in a Degraded Coastal Wetland of Lake Ontario
Full text linkA 4-year (1993 through 1996) monitoring program examined the distribution of total suspended solids (TSS) in Cootes Paradise Marsh, a shallow (mean depth of 70 cm), degraded, drowned-rivermouth marsh of Lake Ontario. Monthly meteorological and hydrographical data from 1986 through 1996 revealed a hydrologically dynamic system that exhibited large seasonal and interannual variation with respect to precipitation amount, discharge volume, and water levels; the prevailing winds were shown to be oriented along the length of the marsh. Interannual variation in TSS concentrations was inversely related to mean seasonal water levels that fluctuated 45 cm over the 11 years. In a stepwise regression analysis, planktonic chlorophyll-a concentration only explained 2% of the variation in TSS, while inorganic and non-algal organic solids explained 70% and 18%, respectively. Mean seasonal water turbidity increased significantly with mean seasonal wind speed at 17 sampling stations during 1993 and 1994. Runoff from a summer rainstorm more than doubled water turbidities at the mouth of all three creeks over the first 36 hours. In enclosure experiments, water turbidity increased proportionately with biomass of benthivorous fish (especially common carp, Cyprinus carpio). When wind and carp disturbance were compared simultaneously in the field, wind speed accounted for 41% of the variation in turbidity while presence of carp explained an additional 21%. The overall temporal and spatial distribution of TSS in the marsh reflected changes in water level, wind activities, onset of rain events, and fish disturbance that acted in concert to keep Cootes Paradise Marsh extremely turbid throughout the summer
Modern Toolbox to address a decades-old problem in the conservation of freshwater turtles: Blanding's Turtles as a case study.
No full textResearch into freshwater turtles can be challenging because of their physiology, behavioural processes, and interaction with their environments. Traditional monitoring and survey methods such as radio telemetry and visual encounter surveys have many limitations and have experienced few advancements in the past decades. Limitations such as limited behavioural inference, high labour costs and long periods between tracking require the use of a new toolkit to explore novel questions in turtle ecology. Here we briefly summarize the emerging innovated technology including multi-sensor bio-loggers, eDNA, and pattern recognition software and then review questions related to turtle ecology and behaviours that can be addressed using these new tools. Our goals are to highlight the emerging methods for Blanding’s turtle conservation and encourage researchers to incorporate this new toolkit into their research programs
Using the Blanding's Turtle (Emydoidea blandingii) plastron as a 'fingerprint': photo identification of an endangered species
Full text linkThe ability to uniquely identify individuals is critical to estimating and monitoring trends in population sizes, one of the key metrics used to evaluate a species’ conservation status and success of mitigation strategies. For freshwater turtles, shell notching and/or passive integrated transponder (PIT) tags are commonly used to mark individuals. However, because notch codes and PIT tags can be lost over time and require more invasive procedures, we explored if photographs offer an effective method to reliably identify individuals. The Blanding’s turtle (Emydoidea blandingii) is a globally endangered species with distinct black and yellow markings on its plastron. We used the I3 S Pattern software with custom parameters to classify patterns on Blanding’s turtle plastrons and to identify individuals. We analyzed 826 plastron images from 707 individual Blanding’s turtles taken between 1998 and 2019 from 12 study areas distributed throughout their Canadian range. When plastron photos were pooled across the sampled range (i.e., all study areas), there was an 84% probability of correctly identifying an individual turtle within the top 3 suggested matches, whereas when identifying Blanding’s turtles within a specific study area, identification accuracy was 82% in Central Ontario and 97% in Nova Scotia. Individual identification from plastron markings did not work well in areas where iron staining obscured the plastron pattern or for hatchlings and juveniles whose patterns changed over time. For example, the only misclassification in the Nova Scotia study area was for a turtle with photos through various life stages. In areas without iron staining, plastron photo identification offers a cost-effective, non-invasive method to identify individual adult Blanding’s turtles to support population monitoring and community science initiatives, and has the potential to assist with range-wide coordination to counteract illegal wildlife trade
Effect of wetland quality on sampling bias associated with two fish survey methods for coastal wetlands of the lower Great Lakes
Full text linkMarcaccio and Chow-Fraser 2018 Final Report to MTO on treatment efficacy
No full textRoadside easements are a unique linear habitat that can be easily invaded by invasive Phragmites australis. While many North American jurisdictions have initiated control programs, few have established associated effectiveness monitoring programs. Here, we propose and apply three methods to determine effectiveness of a regional treatment program undertaken by the Ministry of Transportation of Ontario (MTO) in southwestern Ontario. We utilized 1) high-resolution spring orthophotography, 2) medium resolution multi-seasonal satellite image data and 3) high-resolution multispectral satellite image data to assess the effectiveness of MTO’s treatment program. Using digitization and image classification, we deduced effectiveness of treatment programs in over 3,900 km of roadside habitat between 2010-2015 (orthophotography) and 2016-2018 (satellite data). Net decreases in areal cover of Phragmites were over 95% for all road types other than for major expressways, which saw decreases between 80-95% between 2010 and 2015 but only 20-55% between 2016 and 2018. The areal cover of Phragmites also increased more rapidly within untreated expressway habitat compared with other road types over the same time period. Although orthophotography (20-cm resolution) acquired in spring yielded good results for identification of invasive Phragmites, it is only available once every five years on a provincial scale. By comparison, medium resolution satellite data (Sentinel-2) provided good results within large expressways (with larger and wider easements/habitat area) but was poor for all other road types (<2 lanes). These data miss small patches which are confirmed through high-resolution satellite data (Worldview 3; <1.5m). We advocate for use of medium-resolution satellite data for annual baseline information on expressways, and high-resolution satellite data before and after treatment programs to directly assess effectiveness at smaller spatial scales
Chow-Fraser et al. 2003 Frenchman's Bay
No full textWe conducted a two-year (2001-3) study to assess the impacts of urbanization on the water quality and fish habitat of Frenchman’s Bay, which is located in a highly urbanized watershed of Lake Ontario, Canada. During summer (end of May to mid-September) 2002, continuous monitoring devices were installed in two main tributaries, Amberlea Creek (below Hwy 401) and Pine Creek (above Hwy 401), and in two stations of the bay to measure a suite of physico-chemical parameters. Because of the low water levels, the monitoring was discontinued in the marsh, but was maintained in Amberlea and Pine Creeks from September 2002 to end of March 2003. We also carried out a parallel biweekly sampling program for nutrient and suspended solids at an open-water station during the summer of 2002 and one winter sampling trip in January 2003. Our investigation of the aquatic food-web included a survey of the aquatic plant community during the summer of 2001 and 2002, and a wetland-fish community survey that included nine sampling occasions between August 2001 and November 2002.
The negative impact of runoff from Hwy 401 on the water quality of Amberlea Creek was clear: elevated levels of suspended solids and dissolved nutrients in summer, and elevated water turbidity and conductivity during winter could be linked directly to the onset of precipitation events. By comparison, water quality of the Pine Creek station, which is located well above the highway, did not exhibit the same degree of degradation, although we suspect that similarly degraded conditions would be found in Pine Creek downstream of Hwy 401. The heavier than normal rainstorms in July 2002 gave an excellent opportunity to observe the effects of storm events on creeks, while drier and hotter than normal weather in August allowed us a glimpse into how the marsh may behave if similar conditions anticipated by global climate change models are realized. We suggest that the marsh will become less hospitable to fish in such a scenario because water levels will be lower, water will stay warmer through the night, and become poorly oxygenated.
Composite maps of physico-chemical conditions in Frenchman’s Bay, supplemented by information from a biweekly monitoring program revealed significant site-to-site differences in water quality. The three long-term sites we monitored during the summer of 2002 had very distinct characteristics. The Open station was deep (about 3.0 m), had warm surface water, lower conductivity, high DO content and low chlorophyll and turbidity. This description is consistent with the lower nutrient and suspended solids data reported for this station in a previous year. By comparison, the North station was shallow and warm, and seemed to be the most polluted of the three sites, with high conductivity, high chlorophyll and turbidity, and relatively low oxygen content. Like the North station, the South station was also shallow and warm, but was well- oxygented and had lower conductivity, chlorophyll and turbidity levels.
There are a number of indicators of ecosystem health that can be used to assess the quality of fish habitat in a coastal wetland such as Frenchman’s Bay. In this study, we use a number of recently developed indicators based on physico-chemical and biological information (Chow- Fraser, unpub. data, McMaster University). A Wetland Water Quality Index (WQI) has been developed that is based on the findings from Crosbie and Chow-Fraser (1999) and Lougheed et al. (2001) in which water- and sediment-quality of wetlands located along all of the Canadian Great Lakes have been related to altered land uses in their watershed. In addition, we use information on macrophyte diversity as discussed in Lougheed et al. (2001), the Wetland Zooplankton Index (WZI) developed by Lougheed and Chow-Fraser (2002), and the periphyton index developed by McNair and Chow-Fraser (2003), and an unpublished index based on the biomass of zoobnethos to assess the ecological status of Frenchman’s Bay. All of the bioindicators point to Frenchman’s Bay as being moderately degraded, although in better condition than other urban coastal marshes along the Lake Ontario shoreline. That may explain why it still attracts a surprisingly large number of spawning and nursery fish throughout the spring and summer.
Continuous water-quality monitoring should be continued for at least one more year in the creeks to supplement information in the current survey. We also recommend that the daily water samples taken in 2002 be processed and analyzed for nutrients and heavy metals (cadmium, copper, lead and zinc) to assess the degree and type of pollution from highway runoff. Water quality and the fish community in the marsh have already been well characterized in this study, although the fish community in the creeks will require further investigation. To improve habitat for the existing fish community, consideration should be given to enhancing and amalgamating the “islands” of emergent vegetation that currently exist in the north end of the lagoon. Since water quality in the north show obvious signs of pollution from the creeks, it would be desirable to redirect the highway runoff through a retention pond to remove the sediment and pollutants before the water is allowed to flow into the bay